Patchwork ARM: OMAP: AM33XX: CAN: d_can: Add support for Bosch D_CAN controller

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Submitter AnilKumar Chimata
Date April 3, 2012, 12:32 p.m.
Message ID <1333456339-9372-1-git-send-email-anilkumar@ti.com>
Download mbox | patch
Permalink /patch/150424/
State Awaiting Upstream
Delegated to: David Miller
Headers show

Comments

AnilKumar Chimata - April 3, 2012, 12:32 p.m.
This patch adds the support for Bosch D_CAN controller.

Bosch D_CAN controller is a full-CAN implementation compliant to
CAN protocol version 2.0 part A and B. Bosch D_CAN user manual
can be obtained from: http://www.semiconductors.bosch.de/media/
en/pdf/ipmodules_1/can/d_can_users_manual_111.pdf

D_CAN device is used on many SoCs like AM335x, DM8148 and DM813x
EVMs from TI, D_CAN details on AM335x can be accessed from:
http://www.ti.com/lit/ug/spruh73c/spruh73c.pdf

D_CAN can be configurable for 16, 32, 64 and 128 message objects.
The driver implementation is based on 64 message objects.

Following are the design choices made while writing the controller
driver:
1. Interface Register set IF0 has be used for receive and IF1 is
   used for transmit message objects.
2. Out of the total Message objects available, half of it are kept
   aside for RX purposes and the rest for TX purposes.
3. NAPI implementation is such that both the TX and RX paths
   functions in polling mode.

Signed-off-by: AnilKumar Ch <anilkumar@ti.com>
---
 drivers/net/can/Kconfig            |   14 +
 drivers/net/can/Makefile           |    1 +
 drivers/net/can/d_can.c            | 1487 ++++++++++++++++++++++++++++++++++++
 include/linux/can/platform/d_can.h |   40 +
 4 files changed, 1542 insertions(+), 0 deletions(-)
 create mode 100644 drivers/net/can/d_can.c
 create mode 100644 include/linux/can/platform/d_can.h
AnilKumar Chimata - April 3, 2012, 12:39 p.m.
Hi All,

Subject line of this patch should be
"ARM: CAN: d_can: Add support for Bosch D_CAN controller"

Regards
AnilKumar
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Wolfgang Grandegger - April 3, 2012, 12:44 p.m.
On 04/03/2012 02:32 PM, AnilKumar Ch wrote:
> This patch adds the support for Bosch D_CAN controller.
> 
> Bosch D_CAN controller is a full-CAN implementation compliant to
> CAN protocol version 2.0 part A and B. Bosch D_CAN user manual
> can be obtained from: http://www.semiconductors.bosch.de/media/
> en/pdf/ipmodules_1/can/d_can_users_manual_111.pdf
> 
> D_CAN device is used on many SoCs like AM335x, DM8148 and DM813x
> EVMs from TI, D_CAN details on AM335x can be accessed from:
> http://www.ti.com/lit/ug/spruh73c/spruh73c.pdf
> 
> D_CAN can be configurable for 16, 32, 64 and 128 message objects.
> The driver implementation is based on 64 message objects.
> 
> Following are the design choices made while writing the controller
> driver:
> 1. Interface Register set IF0 has be used for receive and IF1 is
>    used for transmit message objects.
> 2. Out of the total Message objects available, half of it are kept
>    aside for RX purposes and the rest for TX purposes.
> 3. NAPI implementation is such that both the TX and RX paths
>    functions in polling mode.
> 
> Signed-off-by: AnilKumar Ch <anilkumar@ti.com>

Please explain why this CAN controller cannot be handled by the existing
C_CAN driver, eventually with some extensions. The register layout seems
almost identical, at least.

Wolfgang.




> ---
>  drivers/net/can/Kconfig            |   14 +
>  drivers/net/can/Makefile           |    1 +
>  drivers/net/can/d_can.c            | 1487 ++++++++++++++++++++++++++++++++++++
>  include/linux/can/platform/d_can.h |   40 +
>  4 files changed, 1542 insertions(+), 0 deletions(-)
>  create mode 100644 drivers/net/can/d_can.c
>  create mode 100644 include/linux/can/platform/d_can.h
> 
> diff --git a/drivers/net/can/Kconfig b/drivers/net/can/Kconfig
> index bb709fd..2529cba 100644
> --- a/drivers/net/can/Kconfig
> +++ b/drivers/net/can/Kconfig
> @@ -68,6 +68,20 @@ config CAN_TI_HECC
>  	  Driver for TI HECC (High End CAN Controller) module found on many
>  	  TI devices. The device specifications are available from www.ti.com
>  
> +config CAN_D_CAN
> +	tristate "Bosch D_CAN Controller"
> +	depends on CAN_DEV
> +	---help---
> +	  This driver adds support for the D_CAN device found in
> +	  many SoCs like am335x, dm814x and dm813x boards from TI.
> +
> +	  The device user guide can be accessed from
> +	  http://www.semiconductors.bosch.de/media/en/pdf/ipmodules_1/
> +	  can/d_can_users_manual_111.pdf
> +
> +	  To compile this driver as a module, choose M here: the
> +	  module will be called d_can.
> +
>  config CAN_MCP251X
>  	tristate "Microchip MCP251x SPI CAN controllers"
>  	depends on CAN_DEV && SPI && HAS_DMA
> diff --git a/drivers/net/can/Makefile b/drivers/net/can/Makefile
> index 938be37..4bd3a87 100644
> --- a/drivers/net/can/Makefile
> +++ b/drivers/net/can/Makefile
> @@ -17,6 +17,7 @@ obj-$(CONFIG_CAN_C_CAN)		+= c_can/
>  obj-$(CONFIG_CAN_CC770)		+= cc770/
>  obj-$(CONFIG_CAN_AT91)		+= at91_can.o
>  obj-$(CONFIG_CAN_TI_HECC)	+= ti_hecc.o
> +obj-$(CONFIG_CAN_D_CAN)		+= d_can.o
>  obj-$(CONFIG_CAN_MCP251X)	+= mcp251x.o
>  obj-$(CONFIG_CAN_BFIN)		+= bfin_can.o
>  obj-$(CONFIG_CAN_JANZ_ICAN3)	+= janz-ican3.o
> diff --git a/drivers/net/can/d_can.c b/drivers/net/can/d_can.c
> new file mode 100644
> index 0000000..51e2986
> --- /dev/null
> +++ b/drivers/net/can/d_can.c
> @@ -0,0 +1,1487 @@
> +/*
> + * CAN bus driver for Bosch D_CAN controller
> + *
> + * Copyright (C) 2012 Texas Instruments Incorporated - http://www.ti.com/
> + *
> + * Borrowed from C_CAN driver
> + * Copyright (C) 2010 ST Microelectronics
> + * - Bhupesh Sharma <bhupesh.sharma@st.com>
> + *
> + * Borrowed heavily from the C_CAN driver originally written by:
> + * Copyright (C) 2007
> + * - Sascha Hauer, Marc Kleine-Budde, Pengutronix <s.hauer@pengutronix.de>
> + * - Simon Kallweit, intefo AG <simon.kallweit@intefo.ch>
> + *
> + * Bosch D_CAN controller is compliant to CAN protocol version 2.0 part A and B.
> + * Bosch D_CAN user manual can be obtained from:
> + * http://www.semiconductors.bosch.de/media/en/pdf/ipmodules_1/can/
> + * d_can_users_manual_111.pdf
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public License as
> + * published by the Free Software Foundation version 2.
> + *
> + * This program is distributed "as is" WITHOUT ANY WARRANTY of any
> + * kind, whether express or implied; without even the implied warranty
> + * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + */
> +
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/interrupt.h>
> +#include <linux/netdevice.h>
> +#include <linux/errno.h>
> +#include <linux/skbuff.h>
> +#include <linux/jiffies.h>
> +#include <linux/pm_runtime.h>
> +#include <linux/platform_device.h>
> +#include <linux/clk.h>
> +#include <linux/io.h>
> +
> +#include <linux/can/dev.h>
> +#include <linux/can/error.h>
> +#include <linux/can/platform/d_can.h>
> +
> +#define D_CAN_DRV_NAME	"d_can"
> +#define D_CAN_VERSION	"1.0"
> +#define D_CAN_DRV_DESC	"CAN bus driver for Bosch D_CAN controller " \
> +			D_CAN_VERSION
> +
> +/* TI D_CAN module registers */
> +#define D_CAN_CTL		0x0	/* CAN control register */
> +#define D_CAN_ES		0x4	/* Error and status */
> +#define D_CAN_PARITYERR_EOI	0x4	/* Parity error EOI */
> +#define D_CAN_ERRC		0x8	/* Error counter */
> +#define D_CAN_BTR		0xC	/* Bit timing */
> +#define D_CAN_INT		0x10	/* Interrupt register */
> +#define D_CAN_TEST		0x14	/* Test register */
> +#define D_CAN_PERR		0x1C	/* Parity Error Code */
> +#define D_CAN_ABOTR		0x80	/* Auto-Bus-On Time */
> +#define D_CAN_TXRQ_X		0x84	/* Transmission Request X */
> +#define D_CAN_TXRQ(n)		(0x88 + ((n) * 4)) /* Transmission request */
> +#define D_CAN_NWDAT_X		0x98	/* New data X register */
> +#define D_CAN_NWDAT(n)		(0x9C + ((n) * 4)) /* New data */
> +#define D_CAN_INTPND_X		0xAC	/* Interrupt Pending X */
> +#define D_CAN_INTPND(n)		(0xB0 + ((n) * 4)) /* Interrupt Pending */
> +#define D_CAN_MSGVAL_X		0xC0		/* Message Valid X */
> +#define D_CAN_MSGVAL(n)		(0xC4 + ((n) * 4)) /* Message Valid */
> +#define D_CAN_INTMUX(n)		(0xD8 + ((n) * 4)) /* Interrupt Multiplexer */
> +#define D_CAN_IFCMD(n)		(0x100 + ((n) * 0x20)) /* Command */
> +#define D_CAN_IFMSK(n)		(0x104 + ((n) * 0x20)) /* Mask */
> +#define D_CAN_IFARB(n)		(0x108 + ((n) * 0x20)) /* Arbitration */
> +#define D_CAN_IFMCTL(n)		(0x10c + ((n) * 0x20)) /* Message ctl */
> +#define D_CAN_IFDATA(n)		(0x110 + ((n) * 0x20)) /* DATA A */
> +#define D_CAN_IFDATB(n)		(0x114 + ((n) * 0x20)) /* DATA B */
> +#define D_CAN_IF3OBS		0x140	/* IF3 Observation */
> +#define D_CAN_IF3UPD(n)		(0x160 + ((n) * 4)) /* Update enable */
> +#define D_CAN_TIOC		0x1E0	/* CAN TX IO Control */
> +#define D_CAN_RIOC		0x1E4	/* CAN RX IO Control */
> +
> +/* Control register Bit fields */
> +#define D_CAN_CTL_WUBA		BIT(26)	/* Automatic wake-up on bus activity */
> +#define D_CAN_CTL_PDR		BIT(24)	/* Request for local low power mode */
> +#define D_CAN_CTL_DE3		BIT(20)	/* Enable DMA request line for IF3 */
> +#define D_CAN_CTL_DE2		BIT(19)	/* Enable DMA request line for IF2 */
> +#define D_CAN_CTL_DE1		BIT(18)	/* Enable DMA request line for IF1 */
> +#define D_CAN_CTL_IE1		BIT(17)	/* Interrupt line 1 enable */
> +#define D_CAN_CTL_INITDBG	BIT(16)	/* Init state for debug access */
> +#define D_CAN_CTL_SWR		BIT(15)	/* S/W reset enable */
> +#define D_CAN_CTL_PMD		(0xF << 10)	/* Parity on/off */
> +#define D_CAN_CTL_ABO		BIT(9)	/* Auto bus on enable */
> +#define D_CAN_CTL_IDS		BIT(8)	/* Interruption debug support enable */
> +#define D_CAN_CTL_TEST		BIT(7)	/* Test mode enable */
> +#define D_CAN_CTL_CCE		BIT(6)	/* Configuration change enable */
> +#define D_CAN_CTL_DISABLE_AR	BIT(5)	/* Disable automatic retransmission */
> +#define D_CAN_CTL_EIE		BIT(3)	/* Error interrupt enable */
> +#define D_CAN_CTL_SIE		BIT(2)	/* Status change int enable */
> +#define D_CAN_CTL_IE0		BIT(1)	/* Interrupt line 0 enable */
> +#define D_CAN_CTL_INIT		BIT(0)	/* D_CAN initialization mode */
> +
> +/* D_CAN Error and Status and Parity Error EOI reg bit fields */
> +#define D_CAN_ES_PDA		BIT(10)	/* Local power-down ACK */
> +#define D_CAN_ES_WUP		BIT(9)	/* Wkae up pending */
> +#define D_CAN_ES_PER		BIT(8)	/* Parity error detected */
> +#define D_CAN_ES_BOFF		BIT(7)	/* Bus off state */
> +#define D_CAN_ES_EWARN		BIT(6)	/* Warning state */
> +#define D_CAN_ES_EPASS		BIT(5)	/* Error passive state */
> +#define D_CAN_ES_RXOK		BIT(4)	/* Received a msg successfully */
> +#define D_CAN_ES_TXOK		BIT(3)	/* Transmitted a msg successfully */
> +#define D_CAN_ES_LEC_MASK	0x7	/* Last error code */
> +
> +/* Error counter reg bit fields */
> +#define D_CAN_ERRC_RP_MASK	BIT(15)		/* Receive error passive */
> +#define D_CAN_ERRC_REC_SHIFT	8
> +#define D_CAN_ERRC_REC_MASK	(0x7F << 8)	/* Receive err counter */
> +#define D_CAN_ERRC_TEC_MASK	(0xFF << 0)	/* Transmit err counter */
> +
> +/* Bit timing reg bit fields */
> +#define D_CAN_BTR_BRPE_SHIFT	16		/* Baud rate prescaler ext */
> +#define D_CAN_BTR_TSEG2_SHIFT	12		/* Time seg after smpl point */
> +#define D_CAN_BTR_TSEG1_SHIFT	8		/* Time seg before smpl point */
> +#define D_CAN_BTR_SJW_SHIFT	6		/* Syncronization jump width */
> +#define D_CAN_BTR_BRP_SHIFT	0		/* Baud rate prescaler */
> +
> +/* D_CAN Test register bit fields */
> +#define D_CAN_TEST_RDA		BIT(9)	/* RAM direct access enable */
> +#define D_CAN_TEST_EXL		BIT(8)	/* External loopback mode */
> +#define D_CAN_TEST_RX		BIT(7)	/* Monitors the reveive pin */
> +#define D_CAN_TEST_TX		(0x3 << 5)	/* Control of CAN_TX pin */
> +#define D_CAN_TEST_LBACK	BIT(4)	/* Loopback mode */
> +#define D_CAN_TEST_SILENT	BIT(3)	/* Silent mdoe */
> +
> +/* D_CAN IF command reg bit fields */
> +#define D_CAN_IF_CMD_WR		BIT(23)	/* Write/read */
> +#define D_CAN_IF_CMD_MASK	BIT(22)	/* Access to mask bits */
> +#define D_CAN_IF_CMD_ARB	BIT(21)	/* Access to arbitration bits */
> +#define D_CAN_IF_CMD_CONTROL	BIT(20)	/* Acess to control bits */
> +#define D_CAN_IF_CMD_CIP	BIT(19)	/* Clear int pending */
> +#define D_CAN_IF_CMD_TXRQST	BIT(18)	/* Access transmission request */
> +#define D_CAN_IF_CMD_DATAA	BIT(17)	/* Access to Data Bytes 0-3 */
> +#define D_CAN_IF_CMD_DATAB	BIT(16)	/* Access to Data Bytes 4-7 */
> +#define D_CAN_IF_CMD_BUSY	BIT(15)	/* Busy flag */
> +#define D_CAN_IF_CMD_DAM	BIT(14)	/* Activation of DMA */
> +#define D_CAN_IF_CMD_MN_MASK	0xFF	/* No. of msg's used for DMA T/F */
> +#define D_CAN_IF_CMD_ALL	(D_CAN_IF_CMD_MASK | D_CAN_IF_CMD_ARB | \
> +				D_CAN_IF_CMD_CONTROL | D_CAN_IF_CMD_TXRQST | \
> +				D_CAN_IF_CMD_DATAA | D_CAN_IF_CMD_DATAB)
> +
> +/* D_CAN IF mask reg bit fields */
> +#define D_CAN_IF_MASK_MX	BIT(31)	/* Mask Extended Identifier */
> +#define D_CAN_IF_MASK_MD	BIT(30)	/* Mask Message direction */
> +
> +/* D_CAN IF Arbitration */
> +#define D_CAN_IF_ARB_MSGVAL	BIT(31)	/* Message Vaild */
> +#define D_CAN_IF_ARB_MSGXTD	BIT(30)	/* Extended Identifier 0-11 1-29 */
> +#define D_CAN_IF_ARB_DIR_XMIT	BIT(29) /* Message direction 0-R 1-T */
> +
> +/* D_CAN IF Message control */
> +#define D_CAN_IF_MCTL_NEWDAT	BIT(15)	/* New data available */
> +#define D_CAN_IF_MCTL_MSGLST	BIT(14)	/* Message lost, only for receive */
> +#define D_CAN_IF_MCTL_INTPND	BIT(13)	/* Interrupt pending */
> +#define D_CAN_IF_MCTL_UMASK	BIT(12)	/* Use acceptance mask */
> +#define D_CAN_IF_MCTL_TXIE	BIT(11)	/* Transmit int enable */
> +#define D_CAN_IF_MCTL_RXIE	BIT(10)	/* Receive int enable */
> +#define D_CAN_IF_MCTL_RMTEN	BIT(9)	/* Remote enable */
> +#define D_CAN_IF_MCTL_TXRQST	BIT(8)	/* Transmit request */
> +#define D_CAN_IF_MCTL_EOB	BIT(7)	/* Data frames */
> +#define D_CAN_IF_MCTL_DLC_MASK	0xF	/* Data length code */
> +
> +/* D_CAN IF3 Observation reg bit fields */
> +#define D_CAN_IF3OBS_UP		BIT(15)	/* Update data status */
> +#define D_CAN_IF3OBS_SDB	BIT(12)	/* DataB read out status */
> +#define D_CAN_IF3OBS_SDA	BIT(11)	/* DataA read out status */
> +#define D_CAN_IF3OBS_SC		BIT(10)	/* Contol bits read out status */
> +#define D_CAN_IF3OBS_SA		BIT(9)	/* Arbitration read out status */
> +#define D_CAN_IF3OBS_SM		BIT(8)	/* Mask bits read out status */
> +#define D_CAN_IF3OBS_DB		BIT(4)	/* Data B read observation */
> +#define D_CAN_IF3OBS_DA		BIT(3)	/* Data A read observation */
> +#define D_CAN_IF3OBS_CTL	BIT(2)	/* Control read observation */
> +#define D_CAN_IF3OBS_ARB	BIT(1)	/* Arbitration data read observation */
> +#define D_CAN_IF3OBS_MASK	BIT(0)	/* Mask data read observation */
> +
> +/* D_CAN TX I/O reg bit fields */
> +#define D_CAN_TIOC_PU		BIT(18)	/* CAN_TX pull up/down select */
> +#define D_CAN_TIOC_PD		BIT(17)	/* CAN_TX pull disable */
> +#define D_CAN_TIOC_OD		BIT(16)	/* CAN_TX open drain enable */
> +#define D_CAN_TIOC_FUNC		BIT(3)	/* CAN_TX function */
> +#define D_CAN_TIOC_DIR		BIT(2)	/* CAN_TX data direction */
> +#define D_CAN_TIOC_OUT		BIT(1)	/* CAN_TX data out write */
> +#define D_CAN_TIOC_IN		BIT(0)	/* CAN_TX data in */
> +
> +/* D_CAN RX I/O reg bit fields */
> +#define D_CAN_RIOC_PU		BIT(18)	/* CAN_RX pull up/down select */
> +#define D_CAN_RIOC_PD		BIT(17)	/* CAN_RX pull disable */
> +#define D_CAN_RIOC_OD		BIT(16)	/* CAN_RX open drain enable */
> +#define D_CAN_RIOC_FUNC		BIT(3)	/* CAN_RX function */
> +#define D_CAN_RIOC_DIR		BIT(2)	/* CAN_RX data direction */
> +#define D_CAN_RIOC_OUT		BIT(1)	/* CAN_RX data out write */
> +#define D_CAN_RIOC_IN		BIT(0)	/* CAN_RX data in */
> +
> +/* IF register masks */
> +#define IFX_WRITE_IDR(x)		((x) & 0x1FFFFFFF)
> +#define IFX_CMD_BITS(x)			((x) & 0xFFFFFF00)
> +#define IFX_CMD_MSG_NUMBER(x)		((x) & 0xFF)
> +
> +/* Message objects split */
> +#define D_CAN_NUM_MSG_OBJECTS		64
> +#define D_CAN_NUM_RX_MSG_OBJECTS	32
> +#define D_CAN_NUM_TX_MSG_OBJECTS	32
> +
> +#define D_CAN_MSG_OBJ_RX_FIRST		1
> +#define D_CAN_MSG_OBJ_RX_LAST		(D_CAN_MSG_OBJ_RX_FIRST + \
> +					D_CAN_NUM_RX_MSG_OBJECTS - 1)
> +
> +#define D_CAN_MSG_OBJ_TX_FIRST		(D_CAN_MSG_OBJ_RX_LAST + 1)
> +#define D_CAN_MSG_OBJ_TX_LAST		(D_CAN_MSG_OBJ_TX_FIRST + \
> +					D_CAN_NUM_TX_MSG_OBJECTS - 1)
> +
> +#define D_CAN_MSG_OBJ_RX_SPLIT		17
> +#define D_CAN_MSG_OBJ_RX_LOW_LAST	(D_CAN_MSG_OBJ_RX_SPLIT - 1)
> +
> +#define D_CAN_NEXT_MSG_OBJ_MASK		(D_CAN_NUM_TX_MSG_OBJECTS - 1)
> +
> +/* global interrupt masks */
> +#define D_CAN_ENABLE_ALL_INTERRUPTS	1
> +#define D_CAN_DISABLE_ALL_INTERRUPTS	0
> +
> +/* status interrupt */
> +#define D_CAN_STATUS_INTERRUPT		0x8000
> +
> +#define D_CAN_BUSY_TIMEOUT		14
> +#define D_CAN_TIMEOUT_MS		1000
> +
> +/* Interface register bank number */
> +#define D_CAN_IF_RX_NUM			0
> +#define D_CAN_IF_TX_NUM			1
> +
> +#define D_CAN_GET_XREG_NUM(priv, reg)	(__ffs(d_can_read(priv, reg)) >> 2)
> +
> +/* d_can private data structure */
> +struct d_can_priv {
> +	struct can_priv can;	/* must be the first member */
> +	struct napi_struct napi;
> +	struct net_device *dev;
> +	struct platform_device *pdev;
> +	unsigned int tx_next;
> +	unsigned int tx_echo;
> +	u32 current_status;
> +	u32 last_status;
> +	u32 irqstatus;
> +	bool is_opened;
> +	void __iomem *base;
> +	void (*ram_init) (unsigned int, unsigned int);
> +};
> +
> +/* CAN Bittiming constants as per D_CAN specs */
> +static struct can_bittiming_const d_can_bittiming_const = {
> +	.name		= D_CAN_DRV_NAME,
> +	.tseg1_min	= 1,	/* Time segment 1 = prop_seg + phase_seg1 */
> +	.tseg1_max	= 16,
> +	.tseg2_min	= 1,	/* Time segment 2 = phase_seg2 */
> +	.tseg2_max	= 8,
> +	.sjw_max	= 4,
> +	.brp_min	= 1,
> +	.brp_max	= 1024,	/* 6-bit BRP field + 4-bit BRPE field*/
> +	.brp_inc	= 1,
> +};
> +
> +/* d_can last error code (lec) values */
> +enum d_can_lec_type {
> +	LEC_NO_ERROR = 0,
> +	LEC_STUFF_ERROR,
> +	LEC_FORM_ERROR,
> +	LEC_ACK_ERROR,
> +	LEC_BIT1_ERROR,
> +	LEC_BIT0_ERROR,
> +	LEC_CRC_ERROR,
> +	LEC_UNUSED,
> +};
> +
> +/* d_can error types */
> +enum d_can_bus_error_types {
> +	NO_ERROR = 0,
> +	BUS_OFF,
> +	ERROR_WARNING,
> +	ERROR_PASSIVE,
> +};
> +
> +static inline void d_can_write(struct d_can_priv *priv, u32 reg, u32 val)
> +{
> +	writel(val, priv->base + reg);
> +}
> +
> +static inline u32 d_can_read(struct d_can_priv *priv, u32 reg)
> +{
> +	return readl(priv->base + reg);
> +}
> +
> +static inline void d_can_set_bit(struct d_can_priv *priv, u32 reg, u32 bitmask)
> +{
> +	d_can_write(priv, reg, d_can_read(priv, reg) | bitmask);
> +}
> +
> +static inline u32 d_can_get_bit(struct d_can_priv *priv, u32 reg, u32 bitmask)
> +{
> +	return (d_can_read(priv, reg) & bitmask) ? 1 : 0;
> +}
> +
> +static inline void d_can_clear_bit(struct d_can_priv *priv, u32 reg,
> +							u32 bitmask)
> +{
> +	d_can_write(priv, reg, d_can_read(priv, reg) & ~bitmask);
> +}
> +
> +static inline int get_tx_next_msg_obj(const struct d_can_priv *priv)
> +{
> +	return (priv->tx_next & D_CAN_NEXT_MSG_OBJ_MASK) +
> +			D_CAN_MSG_OBJ_TX_FIRST;
> +}
> +
> +static inline int get_tx_echo_msg_obj(const struct d_can_priv *priv)
> +{
> +	return (priv->tx_echo & D_CAN_NEXT_MSG_OBJ_MASK) +
> +			D_CAN_MSG_OBJ_TX_FIRST;
> +}
> +
> +static void d_can_interrupts(struct d_can_priv *priv, unsigned int enable)
> +{
> +	unsigned int cntrl_save = d_can_read(priv, D_CAN_CTL);
> +
> +	if (enable)
> +		cntrl_save |= (D_CAN_CTL_IE1 | D_CAN_CTL_EIE |
> +				D_CAN_CTL_SIE | D_CAN_CTL_IE0);
> +	else
> +		cntrl_save &= ~(D_CAN_CTL_IE1 | D_CAN_CTL_EIE |
> +				D_CAN_CTL_SIE | D_CAN_CTL_IE0);
> +
> +	d_can_write(priv, D_CAN_CTL, cntrl_save);
> +}
> +
> +static inline int d_can_msg_obj_is_busy(struct d_can_priv *priv, u32 iface)
> +{
> +	unsigned long time_out = jiffies + msecs_to_jiffies(D_CAN_BUSY_TIMEOUT);
> +
> +	/* Check the status of busy bit */
> +	while (d_can_get_bit(priv, D_CAN_IFCMD(iface), D_CAN_IF_CMD_BUSY) &&
> +					time_after(time_out, jiffies))
> +		cpu_relax();
> +
> +	if (time_after(jiffies, time_out))
> +		return -ETIMEDOUT;
> +
> +	return 0;
> +}
> +
> +static inline void d_can_object_get(struct net_device *dev,
> +				u32 iface, u32 objno, u32 mask)
> +{
> +	struct d_can_priv *priv = netdev_priv(dev);
> +
> +	d_can_write(priv, D_CAN_IFCMD(iface), IFX_CMD_BITS(mask) |
> +					IFX_CMD_MSG_NUMBER(objno));
> +
> +	/*
> +	 * As per specs, after writing the message object number in the
> +	 * IF command register the transfer b/w interface register and
> +	 * message RAM must be complete in 4 - 14 CAN-CLK period.
> +	 */
> +	if (d_can_msg_obj_is_busy(priv, iface))
> +		netdev_err(dev, "timed out in object get\n");
> +}
> +
> +static inline void d_can_object_put(struct net_device *dev,
> +				u32 iface, u32 objno, u32 mask)
> +{
> +	struct d_can_priv *priv = netdev_priv(dev);
> +
> +	d_can_write(priv, D_CAN_IFCMD(iface), D_CAN_IF_CMD_WR |
> +		IFX_CMD_BITS(mask) | IFX_CMD_MSG_NUMBER(objno));
> +
> +	/*
> +	 * As per specs, after writing the message object number in the
> +	 * IF command register the transfer b/w interface register and
> +	 * message RAM must be complete in 4 - 14 CAN-CLK period.
> +	 */
> +	if (d_can_msg_obj_is_busy(priv, iface))
> +		netdev_err(dev, "timed out in object put\n");
> +}
> +
> +static void d_can_write_msg_object(struct net_device *dev, u32 iface,
> +				struct can_frame *frame, u32 objno)
> +{
> +	struct d_can_priv *priv = netdev_priv(dev);
> +	unsigned int id;
> +	u32 flags = 0;
> +
> +	if (!(frame->can_id & CAN_RTR_FLAG))
> +		flags |= D_CAN_IF_ARB_DIR_XMIT;
> +
> +	if (frame->can_id & CAN_EFF_FLAG) {
> +		id = frame->can_id & CAN_EFF_MASK;
> +		flags |= D_CAN_IF_ARB_MSGXTD;
> +	} else
> +		id = ((frame->can_id & CAN_SFF_MASK) << 18);
> +
> +	flags |= D_CAN_IF_ARB_MSGVAL;
> +	d_can_write(priv, D_CAN_IFARB(iface), IFX_WRITE_IDR(id) | flags);
> +
> +	/* Writing lower 4bytes to DATAA IF register */
> +	d_can_write(priv, D_CAN_IFDATA(iface),
> +				le32_to_cpu(*(u32 *)(frame->data)));
> +
> +	/* Writing higher 4bytes to DATAB IF register */
> +	if (frame->can_dlc > 4)
> +		d_can_write(priv, D_CAN_IFDATB(iface),
> +				le32_to_cpu(*(u32 *)(frame->data + 4)));
> +
> +	/* enable TX interrupt for this message object */
> +	d_can_write(priv, D_CAN_IFMCTL(iface),
> +			D_CAN_IF_MCTL_TXIE | D_CAN_IF_MCTL_EOB |
> +			D_CAN_IF_MCTL_TXRQST | D_CAN_IF_MCTL_NEWDAT |
> +			frame->can_dlc);
> +
> +	/* Put message data into message RAM */
> +	d_can_object_put(dev, iface, objno, D_CAN_IF_CMD_ALL);
> +}
> +
> +/*
> + * Mark that this particular message object is received and clearing
> + * the interrupt pending register value.
> + */
> +static inline void d_can_mark_rx_msg_obj(struct net_device *dev,
> +			u32 iface, u32 ctrl_mask, u32 objno)
> +{
> +	struct d_can_priv *priv = netdev_priv(dev);
> +
> +	d_can_write(priv, D_CAN_IFMCTL(iface), ctrl_mask &
> +			~(D_CAN_IF_MCTL_MSGLST | D_CAN_IF_MCTL_INTPND));
> +	d_can_object_put(dev, iface, objno, D_CAN_IF_CMD_CONTROL);
> +}
> +
> +static inline void d_can_activate_all_lower_rx_msg_objs(struct net_device *dev,
> +						u32 iface, u32 ctrl_mask)
> +{
> +	unsigned int i;
> +	struct d_can_priv *priv = netdev_priv(dev);
> +
> +	for (i = D_CAN_MSG_OBJ_RX_FIRST; i <= D_CAN_MSG_OBJ_RX_LOW_LAST; i++) {
> +		d_can_write(priv, D_CAN_IFMCTL(iface), ctrl_mask &
> +				~(D_CAN_IF_MCTL_MSGLST | D_CAN_IF_MCTL_INTPND |
> +				D_CAN_IF_MCTL_NEWDAT));
> +		d_can_object_put(dev, iface, i, D_CAN_IF_CMD_CONTROL);
> +	}
> +}
> +
> +static inline void d_can_activate_rx_msg_obj(struct net_device *dev,
> +				u32 iface, u32 ctrl_mask, u32 objno)
> +{
> +	struct d_can_priv *priv = netdev_priv(dev);
> +
> +	d_can_write(priv, D_CAN_IFMCTL(iface), ctrl_mask &
> +			~(D_CAN_IF_MCTL_MSGLST | D_CAN_IF_MCTL_INTPND |
> +			D_CAN_IF_MCTL_NEWDAT));
> +	d_can_object_put(dev, iface, objno, D_CAN_IF_CMD_CONTROL);
> +}
> +
> +static void d_can_handle_lost_msg_obj(struct net_device *dev,
> +					u32 iface, u32 objno)
> +{
> +	struct d_can_priv *priv = netdev_priv(dev);
> +	struct net_device_stats *stats = &dev->stats;
> +	struct sk_buff *skb;
> +	struct can_frame *frame;
> +
> +	netdev_err(dev, "msg lost in buffer %d\n", objno);
> +	d_can_object_get(dev, iface, objno, D_CAN_IF_CMD_ALL &
> +					~D_CAN_IF_CMD_TXRQST);
> +	d_can_clear_bit(priv, D_CAN_IFMCTL(iface), D_CAN_IF_MCTL_MSGLST);
> +	d_can_object_put(dev, iface, objno, D_CAN_IF_CMD_CONTROL);
> +
> +	/* create an error msg */
> +	skb = alloc_can_err_skb(dev, &frame);
> +	if (unlikely(!skb))
> +		return;
> +
> +	frame->can_id |= CAN_ERR_CRTL;
> +	frame->data[1] = CAN_ERR_CRTL_RX_OVERFLOW;
> +	stats->rx_errors++;
> +	stats->rx_over_errors++;
> +
> +	netif_receive_skb(skb);
> +}
> +
> +static int d_can_read_msg_object(struct net_device *dev, u32 iface, u32 ctrl)
> +{
> +	unsigned int arb_val, mctl_val;
> +	struct d_can_priv *priv = netdev_priv(dev);
> +	struct net_device_stats *stats = &dev->stats;
> +	struct can_frame *frame;
> +	struct sk_buff *skb;
> +	u32 data = 0;
> +
> +	skb = alloc_can_skb(dev, &frame);
> +	if (!skb) {
> +		stats->rx_dropped++;
> +		return -ENOMEM;
> +	}
> +
> +	frame->can_dlc = get_can_dlc(ctrl & 0x0F);
> +	arb_val = d_can_read(priv, D_CAN_IFARB(iface));
> +	mctl_val = d_can_read(priv, D_CAN_IFMCTL(iface));
> +
> +	if (arb_val & D_CAN_IF_ARB_MSGXTD)
> +		frame->can_id = (arb_val & CAN_EFF_MASK) | CAN_EFF_FLAG;
> +	else
> +		frame->can_id = (arb_val >> 18) & CAN_SFF_MASK;
> +
> +	if (mctl_val & D_CAN_IF_MCTL_RMTEN)
> +		frame->can_id |= CAN_RTR_FLAG;
> +	else {
> +		data = d_can_read(priv, D_CAN_IFDATA(iface));
> +		/* Writing MO lower 4 data bytes to skb */
> +		*(u32 *)(frame->data) = cpu_to_le32(data);
> +
> +		/* Writing MO higher 4 data bytes to skb */
> +		if (frame->can_dlc > 4) {
> +			data = d_can_read(priv, D_CAN_IFDATB(iface));
> +			*(u32 *)(frame->data + 4) = cpu_to_le32(data);
> +		} else
> +			*(u32 *)(frame->data + 4) = 0;
> +	}
> +
> +	netif_receive_skb(skb);
> +	stats->rx_packets++;
> +	stats->rx_bytes += frame->can_dlc;
> +
> +	return 0;
> +}
> +
> +static void d_can_setup_receive_object(struct net_device *dev, u32 iface,
> +				u32 objno, u32 mask, u32 id, u32 mcont)
> +{
> +	struct d_can_priv *priv = netdev_priv(dev);
> +
> +	d_can_write(priv, D_CAN_IFMCTL(iface), mcont);
> +	d_can_write(priv, D_CAN_IFMSK(iface), IFX_WRITE_IDR(mask));
> +	d_can_write(priv, D_CAN_IFARB(iface), IFX_WRITE_IDR(id) |
> +						D_CAN_IF_ARB_MSGVAL);
> +	d_can_object_put(dev, iface, objno, D_CAN_IF_CMD_ALL &
> +					~D_CAN_IF_CMD_TXRQST);
> +
> +	netdev_dbg(dev, "obj no:%d, msgval:0x%08x\n", objno, d_can_read(priv,
> +		D_CAN_MSGVAL(D_CAN_GET_XREG_NUM(priv, D_CAN_MSGVAL_X))));
> +}
> +
> +static void d_can_inval_msg_object(struct net_device *dev, u32 iface, u32 objno)
> +{
> +	struct d_can_priv *priv = netdev_priv(dev);
> +
> +	d_can_write(priv, D_CAN_IFARB(iface), 0);
> +	d_can_write(priv, D_CAN_IFMCTL(iface), 0);
> +	d_can_object_put(dev, iface, objno, D_CAN_IF_CMD_ARB |
> +					D_CAN_IF_CMD_CONTROL);
> +
> +	netdev_dbg(dev, "obj no:%d, msgval:0x%08x\n", objno, d_can_read(priv,
> +		D_CAN_MSGVAL(D_CAN_GET_XREG_NUM(priv, D_CAN_MSGVAL_X))));
> +}
> +
> +static inline int d_can_is_next_tx_obj_busy(struct d_can_priv *priv, u32 objno)
> +{
> +	u32 txrq_x_reg_val = D_CAN_GET_XREG_NUM(priv, D_CAN_TXRQ_X);
> +
> +	/* Transmission request register's bit n-1 corresponds to
> +	 * message object n, we need to handle the same properly */
> +	if (d_can_read(priv, D_CAN_TXRQ(txrq_x_reg_val)) &
> +			(1 << (objno - D_CAN_MSG_OBJ_TX_FIRST)))
> +		return 1;
> +
> +	return 0;
> +}
> +
> +static netdev_tx_t d_can_start_xmit(struct sk_buff *skb, struct net_device *dev)
> +{
> +	u32 msg_obj_no;
> +	struct d_can_priv *priv = netdev_priv(dev);
> +	struct can_frame *frame = (struct can_frame *)skb->data;
> +
> +	if (can_dropped_invalid_skb(dev, skb))
> +		return NETDEV_TX_OK;
> +
> +	msg_obj_no = get_tx_next_msg_obj(priv);
> +
> +	/* prepare message object for transmission */
> +	d_can_write_msg_object(dev, D_CAN_IF_TX_NUM, frame, msg_obj_no);
> +	can_put_echo_skb(skb, dev, msg_obj_no - D_CAN_MSG_OBJ_TX_FIRST);
> +
> +	/*
> +	 * we have to stop the queue in case of a wrap around or
> +	 * if the next TX message object is still in use
> +	 */
> +	priv->tx_next++;
> +	if (d_can_is_next_tx_obj_busy(priv, get_tx_next_msg_obj(priv)) ||
> +		((priv->tx_next & D_CAN_NEXT_MSG_OBJ_MASK) == 0))
> +		netif_stop_queue(dev);
> +
> +	return NETDEV_TX_OK;
> +}
> +
> +static void d_can_set_bittiming(struct net_device *dev)
> +{
> +	struct d_can_priv *priv = netdev_priv(dev);
> +	const struct can_bittiming *bt = &priv->can.bittiming;
> +	u32 can_btc;
> +
> +	can_btc = ((bt->phase_seg2 - 1) & 0x7) << D_CAN_BTR_TSEG2_SHIFT;
> +	can_btc |= ((bt->phase_seg1 + bt->prop_seg - 1) & 0xF) <<
> +						D_CAN_BTR_TSEG1_SHIFT;
> +	can_btc |= ((bt->sjw - 1) & 0x3) << D_CAN_BTR_SJW_SHIFT;
> +	/* Ten bits contains the BRP, 6 bits for BRP and upper 4 bits for brpe*/
> +	can_btc |= ((bt->brp - 1) & 0x3F) << D_CAN_BTR_BRP_SHIFT;
> +	can_btc |= ((((bt->brp - 1) >> 6) & 0xF) << D_CAN_BTR_BRPE_SHIFT);
> +
> +	d_can_write(priv, D_CAN_BTR, can_btc);
> +	netdev_info(dev, "setting CAN BT = %#x\n", can_btc);
> +}
> +
> +/*
> + * Configure D_CAN message objects for Tx and Rx purposes:
> + * D_CAN provides a total of 64 message objects that can be configured
> + * either for Tx or Rx purposes. In this driver first 32 message objects
> + * are used as a reception FIFO and the reception FIFO is signified by the
> + * EoB bit being SET. The remaining 32 message objects are kept aside for
> + * Tx purposes. See user guide document for further details on configuring
> + * message objects.
> + */
> +static void d_can_configure_msg_objects(struct net_device *dev)
> +{
> +	unsigned int i;
> +
> +	/* first invalidate all message objects */
> +	for (i = D_CAN_MSG_OBJ_RX_FIRST; i <= D_CAN_NUM_MSG_OBJECTS; i++)
> +		d_can_inval_msg_object(dev, D_CAN_IF_RX_NUM, i);
> +
> +	/* setup receive message objects */
> +	for (i = D_CAN_MSG_OBJ_RX_FIRST; i < D_CAN_MSG_OBJ_RX_LAST; i++)
> +		d_can_setup_receive_object(dev, D_CAN_IF_RX_NUM, i, 0, 0,
> +			(D_CAN_IF_MCTL_RXIE | D_CAN_IF_MCTL_UMASK) &
> +			~D_CAN_IF_MCTL_EOB);
> +
> +	/* Last object EoB bit should be 1 for terminate */
> +	d_can_setup_receive_object(dev, D_CAN_IF_RX_NUM, D_CAN_MSG_OBJ_RX_LAST,
> +			0, 0, D_CAN_IF_MCTL_RXIE | D_CAN_IF_MCTL_UMASK |
> +			D_CAN_IF_MCTL_EOB);
> +}
> +
> +static void d_can_test_mode(struct net_device *dev)
> +{
> +	struct d_can_priv *priv = netdev_priv(dev);
> +
> +	/* Test mode is enabled in this step & the specific TEST bits
> +	 * are enabled accordingly */
> +	d_can_write(priv, D_CAN_CTL, D_CAN_CTL_EIE |
> +			D_CAN_CTL_IE1 |	D_CAN_CTL_IE0 | D_CAN_CTL_TEST);
> +
> +	if (priv->can.ctrlmode & CAN_CTRLMODE_LISTENONLY)
> +		/* silent mode : bus-monitoring mode */
> +		d_can_write(priv, D_CAN_TEST, D_CAN_TEST_SILENT);
> +	else if (priv->can.ctrlmode & CAN_CTRLMODE_LOOPBACK)
> +		/* loopback mode : useful for self-test function */
> +		d_can_write(priv, D_CAN_TEST, D_CAN_TEST_LBACK);
> +	else
> +		/* loopback + silent mode : useful for hot self-test */
> +		d_can_write(priv, D_CAN_TEST, D_CAN_TEST_LBACK |
> +				D_CAN_TEST_SILENT);
> +}
> +
> +/*
> + * Configure D_CAN chip:
> + * - enable/disable auto-retransmission
> + * - set operating mode
> + * - configure message objects
> + */
> +static void d_can_init(struct net_device *dev)
> +{
> +	struct d_can_priv *priv = netdev_priv(dev);
> +	unsigned long time_out;
> +
> +	netdev_dbg(dev, "resetting d_can ...\n");
> +	d_can_set_bit(priv, D_CAN_CTL, D_CAN_CTL_SWR);
> +
> +	/* Enter initialization mode by setting the Init bit */
> +	d_can_set_bit(priv, D_CAN_CTL, D_CAN_CTL_INIT);
> +
> +	/* enable automatic retransmission */
> +	d_can_clear_bit(priv, D_CAN_CTL, D_CAN_CTL_DISABLE_AR);
> +
> +	/* Set the Configure Change Enable ( CCE) bit */
> +	d_can_set_bit(priv, D_CAN_CTL, D_CAN_CTL_CCE);
> +
> +	/* Wait for the Init bit to get set */
> +	time_out = jiffies + msecs_to_jiffies(D_CAN_TIMEOUT_MS);
> +	while (!d_can_get_bit(priv, D_CAN_CTL, D_CAN_CTL_INIT) &&
> +					time_after(time_out, jiffies))
> +		cpu_relax();
> +
> +	if (time_after(jiffies, time_out)) {
> +		netdev_err(dev, "timedout, D_CAN INIT bit is not set\n");
> +		return;
> +	}
> +
> +	/* set bittiming params */
> +	d_can_set_bittiming(dev);
> +
> +	d_can_clear_bit(priv, D_CAN_CTL, D_CAN_CTL_INIT | D_CAN_CTL_CCE);
> +
> +	/* Wait for the Init bit to get clear */
> +	time_out = jiffies + msecs_to_jiffies(D_CAN_TIMEOUT_MS);
> +	while (d_can_get_bit(priv, D_CAN_CTL, D_CAN_CTL_INIT) &&
> +					time_after(time_out, jiffies))
> +		cpu_relax();
> +
> +	if (time_after(jiffies, time_out)) {
> +		netdev_err(dev, "timedout, D_CAN INIT bit is not cleared\n");
> +		return;
> +	}
> +
> +	if (priv->can.ctrlmode & (CAN_CTRLMODE_LOOPBACK |
> +				CAN_CTRLMODE_LISTENONLY))
> +		d_can_test_mode(dev);
> +	else
> +		d_can_write(priv, D_CAN_CTL, D_CAN_CTL_EIE | D_CAN_CTL_IE1 |
> +					D_CAN_CTL_SIE | D_CAN_CTL_IE0);
> +
> +	/* Enable TX and RX I/O Control pins */
> +	d_can_write(priv, D_CAN_TIOC, D_CAN_TIOC_FUNC);
> +	d_can_write(priv, D_CAN_RIOC, D_CAN_RIOC_FUNC);
> +
> +	/* configure message objects */
> +	d_can_configure_msg_objects(dev);
> +
> +	/* set a LEC value so that we can check for updates later */
> +	d_can_write(priv, D_CAN_ES, LEC_UNUSED);
> +}
> +
> +static void d_can_start(struct net_device *dev)
> +{
> +	struct d_can_priv *priv = netdev_priv(dev);
> +
> +	/* basic d_can initialization */
> +	d_can_init(dev);
> +
> +	priv->can.state = CAN_STATE_ERROR_ACTIVE;
> +
> +	/* reset tx helper pointers */
> +	priv->tx_next = priv->tx_echo = 0;
> +
> +	/* enable status change, error and module interrupts */
> +	d_can_interrupts(priv, D_CAN_ENABLE_ALL_INTERRUPTS);
> +}
> +
> +static void d_can_stop(struct net_device *dev)
> +{
> +	struct d_can_priv *priv = netdev_priv(dev);
> +
> +	d_can_interrupts(priv, D_CAN_DISABLE_ALL_INTERRUPTS);
> +
> +	/* set the state as STOPPED */
> +	priv->can.state = CAN_STATE_STOPPED;
> +}
> +
> +static int d_can_set_mode(struct net_device *dev, enum can_mode mode)
> +{
> +	switch (mode) {
> +	case CAN_MODE_START:
> +		d_can_start(dev);
> +		netif_wake_queue(dev);
> +		break;
> +	default:
> +		return -EOPNOTSUPP;
> +	}
> +
> +	return 0;
> +}
> +
> +static int d_can_get_berr_counter(const struct net_device *dev,
> +					struct can_berr_counter *bec)
> +{
> +	unsigned int err_cnt;
> +	struct d_can_priv *priv = netdev_priv(dev);
> +
> +	err_cnt = d_can_read(priv, D_CAN_ERRC);
> +	bec->rxerr = (err_cnt & D_CAN_ERRC_REC_MASK) >> D_CAN_ERRC_REC_SHIFT;
> +	bec->txerr = err_cnt & D_CAN_ERRC_TEC_MASK;
> +
> +	return 0;
> +}
> +
> +/*
> + * priv->tx_echo holds the number of the oldest can_frame put for
> + * transmission into the hardware, but not yet ACKed by the CAN tx
> + * complete IRQ.
> + * We iterate from priv->tx_echo to priv->tx_next and check if the
> + * packet has been transmitted, echo it back to the CAN framework.
> + * If we discover a not yet transmitted packet, stop looking for more.
> + */
> +static void d_can_do_tx(struct net_device *dev)
> +{
> +	u32 msg_obj_no;
> +	struct d_can_priv *priv = netdev_priv(dev);
> +	struct net_device_stats *stats = &dev->stats;
> +	u32 txrq_x_reg_val;
> +	u32 txrq_reg_val;
> +
> +	for (/* nix */; (priv->tx_next - priv->tx_echo) > 0; priv->tx_echo++) {
> +		msg_obj_no = get_tx_echo_msg_obj(priv);
> +		txrq_x_reg_val = D_CAN_GET_XREG_NUM(priv, D_CAN_TXRQ_X);
> +		txrq_reg_val = d_can_read(priv, D_CAN_TXRQ(txrq_x_reg_val));
> +		if (!(txrq_reg_val & (1 << (msg_obj_no -
> +						D_CAN_MSG_OBJ_TX_FIRST)))) {
> +			can_get_echo_skb(dev,
> +					msg_obj_no - D_CAN_MSG_OBJ_TX_FIRST);
> +			stats->tx_bytes += d_can_read(priv,
> +					D_CAN_IFMCTL(D_CAN_IF_TX_NUM)) &
> +					D_CAN_IF_MCTL_DLC_MASK;
> +			stats->tx_packets++;
> +			d_can_inval_msg_object(dev, D_CAN_IF_TX_NUM,
> +					msg_obj_no);
> +		} else
> +			break;
> +	}
> +
> +	/* restart queue if wrap-up or if queue stalled on last pkt */
> +	if (((priv->tx_next & D_CAN_NEXT_MSG_OBJ_MASK) != 0) ||
> +		((priv->tx_echo & D_CAN_NEXT_MSG_OBJ_MASK) == 0))
> +		netif_wake_queue(dev);
> +}
> +
> +/*
> + * d_can core saves a received CAN message into the first free message
> + * object it finds free (starting with the lowest). Bits NEWDAT and
> + * INTPND are set for this message object indicating that a new message
> + * has arrived. To work-around this issue, we keep two groups of message
> + * objects whose partitioning is defined by D_CAN_MSG_OBJ_RX_SPLIT.
> + *
> + * To ensure in-order frame reception we use the following
> + * approach while re-activating a message object to receive further
> + * frames:
> + * - if the current message object number is lower than
> + *   D_CAN_MSG_RX_LOW_LAST, do not clear the NEWDAT bit while clearing
> + *   the INTPND bit.
> + * - if the current message object number is equal to
> + *   D_CAN_MSG_RX_LOW_LAST then clear the NEWDAT bit of all lower
> + *   receive message objects.
> + * - if the current message object number is greater than
> + *   D_CAN_MSG_RX_LOW_LAST then clear the NEWDAT bit of
> + *   only this message object.
> + */
> +static int d_can_do_rx_poll(struct net_device *dev, int quota)
> +{
> +	struct d_can_priv *priv = netdev_priv(dev);
> +	unsigned int msg_obj, mctrl_reg_val;
> +	u32 num_rx_pkts = 0;
> +	u32 intpnd_x_reg_val;
> +	u32 intpnd_reg_val;
> +
> +	for (msg_obj = D_CAN_MSG_OBJ_RX_FIRST;
> +		msg_obj <= D_CAN_MSG_OBJ_RX_LAST && quota > 0; msg_obj++) {
> +
> +		intpnd_x_reg_val = D_CAN_GET_XREG_NUM(priv, D_CAN_INTPND_X);
> +		intpnd_reg_val = d_can_read(priv,
> +					D_CAN_INTPND(intpnd_x_reg_val));
> +
> +		/*
> +		 * as interrupt pending register's bit n-1 corresponds to
> +		 * message object n, we need to handle the same properly.
> +		 */
> +		if (intpnd_reg_val & (1 << (msg_obj - 1))) {
> +
> +			d_can_object_get(dev, D_CAN_IF_RX_NUM, msg_obj,
> +					D_CAN_IF_CMD_ALL &
> +					~D_CAN_IF_CMD_TXRQST);
> +
> +			mctrl_reg_val = d_can_read(priv,
> +					D_CAN_IFMCTL(D_CAN_IF_RX_NUM));
> +
> +			if (!(mctrl_reg_val & D_CAN_IF_MCTL_NEWDAT))
> +				continue;
> +
> +			/* read the data from the message object */
> +			d_can_read_msg_object(dev, D_CAN_IF_RX_NUM,
> +						mctrl_reg_val);
> +
> +			if (mctrl_reg_val & D_CAN_IF_MCTL_EOB)
> +				d_can_setup_receive_object(dev, D_CAN_IF_RX_NUM,
> +					D_CAN_MSG_OBJ_RX_LAST, 0, 0,
> +					D_CAN_IF_MCTL_RXIE |
> +					D_CAN_IF_MCTL_UMASK |
> +					D_CAN_IF_MCTL_EOB);
> +
> +			if (mctrl_reg_val & D_CAN_IF_MCTL_MSGLST) {
> +				d_can_handle_lost_msg_obj(dev, D_CAN_IF_RX_NUM,
> +					msg_obj);
> +				num_rx_pkts++;
> +				quota--;
> +				continue;
> +			}
> +
> +			if (msg_obj < D_CAN_MSG_OBJ_RX_LOW_LAST)
> +				d_can_mark_rx_msg_obj(dev, D_CAN_IF_RX_NUM,
> +						mctrl_reg_val, msg_obj);
> +			else if (msg_obj > D_CAN_MSG_OBJ_RX_LOW_LAST)
> +				/* activate this msg obj */
> +				d_can_activate_rx_msg_obj(dev, D_CAN_IF_RX_NUM,
> +						mctrl_reg_val, msg_obj);
> +			else if (msg_obj == D_CAN_MSG_OBJ_RX_LOW_LAST)
> +				/* activate all lower message objects */
> +				d_can_activate_all_lower_rx_msg_objs(dev,
> +						D_CAN_IF_RX_NUM, mctrl_reg_val);
> +
> +			num_rx_pkts++;
> +			quota--;
> +		}
> +	}
> +	return num_rx_pkts;
> +}
> +
> +static inline int d_can_has_handle_berr(struct d_can_priv *priv)
> +{
> +	return (priv->can.ctrlmode & CAN_CTRLMODE_BERR_REPORTING) &&
> +		(priv->current_status & LEC_UNUSED);
> +}
> +
> +static int d_can_handle_state_change(struct net_device *dev,
> +				enum d_can_bus_error_types error_type)
> +{
> +	unsigned int err_cnt;
> +	unsigned int rx_epass;
> +	struct d_can_priv *priv = netdev_priv(dev);
> +	struct net_device_stats *stats = &dev->stats;
> +	struct can_frame *cf;
> +	struct sk_buff *skb;
> +	struct can_berr_counter bec;
> +
> +	/* propagate the error condition to the CAN stack */
> +	skb = alloc_can_err_skb(dev, &cf);
> +	if (unlikely(!skb))
> +		return 0;
> +
> +	d_can_get_berr_counter(dev, &bec);
> +	err_cnt = d_can_read(priv, D_CAN_ERRC);
> +	rx_epass = err_cnt & D_CAN_ERRC_RP_MASK;
> +
> +	switch (error_type) {
> +	case ERROR_WARNING:
> +		/* error warning state */
> +		priv->can.can_stats.error_warning++;
> +		priv->can.state = CAN_STATE_ERROR_WARNING;
> +		cf->can_id |= CAN_ERR_CRTL;
> +		cf->data[1] = (bec.txerr > bec.rxerr) ?
> +			CAN_ERR_CRTL_TX_WARNING :
> +			CAN_ERR_CRTL_RX_WARNING;
> +		cf->data[6] = bec.txerr;
> +		cf->data[7] = bec.rxerr;
> +
> +		break;
> +	case ERROR_PASSIVE:
> +		/* error passive state */
> +		priv->can.can_stats.error_passive++;
> +		priv->can.state = CAN_STATE_ERROR_PASSIVE;
> +		cf->can_id |= CAN_ERR_CRTL;
> +		if (rx_epass)
> +			cf->data[1] |= CAN_ERR_CRTL_RX_PASSIVE;
> +		if (bec.txerr > 127)
> +			cf->data[1] |= CAN_ERR_CRTL_TX_PASSIVE;
> +
> +		cf->data[6] = bec.txerr;
> +		cf->data[7] = bec.rxerr;
> +		break;
> +	case BUS_OFF:
> +		/* bus-off state */
> +		priv->can.state = CAN_STATE_BUS_OFF;
> +		cf->can_id |= CAN_ERR_BUSOFF;
> +		/*
> +		 * disable all interrupts in bus-off mode to ensure that
> +		 * the CPU is not hogged down
> +		 */
> +		d_can_interrupts(priv, D_CAN_DISABLE_ALL_INTERRUPTS);
> +		can_bus_off(dev);
> +		break;
> +	default:
> +		break;
> +	}
> +	netif_receive_skb(skb);
> +	stats->rx_packets++;
> +	stats->rx_bytes += cf->can_dlc;
> +
> +	return 1;
> +}
> +
> +static int d_can_handle_bus_err(struct net_device *dev,
> +				enum d_can_lec_type lec_type)
> +{
> +	struct d_can_priv *priv = netdev_priv(dev);
> +	struct net_device_stats *stats = &dev->stats;
> +	struct can_frame *cf;
> +	struct sk_buff *skb;
> +
> +	/*
> +	 * early exit if no lec update or no error.
> +	 * no lec update means that no CAN bus event has been detected
> +	 * since CPU wrote 0x7 value to status reg.
> +	 */
> +	if (lec_type == LEC_UNUSED || lec_type == LEC_NO_ERROR)
> +		return 0;
> +
> +	/* propagate the error condition to the CAN stack */
> +	skb = alloc_can_err_skb(dev, &cf);
> +	if (unlikely(!skb))
> +		return 0;
> +
> +	/* common for all type of bus errors */
> +	priv->can.can_stats.bus_error++;
> +	stats->rx_errors++;
> +	cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;
> +	cf->data[2] |= CAN_ERR_PROT_UNSPEC;
> +
> +	switch (lec_type) {
> +	case LEC_STUFF_ERROR:
> +		netdev_dbg(dev, "stuff error\n");
> +		cf->data[2] |= CAN_ERR_PROT_STUFF;
> +		break;
> +	case LEC_FORM_ERROR:
> +		netdev_dbg(dev, "form error\n");
> +		cf->data[2] |= CAN_ERR_PROT_FORM;
> +		break;
> +	case LEC_ACK_ERROR:
> +		netdev_dbg(dev, "ack error\n");
> +		cf->data[2] |= (CAN_ERR_PROT_LOC_ACK |
> +				CAN_ERR_PROT_LOC_ACK_DEL);
> +		break;
> +	case LEC_BIT1_ERROR:
> +		netdev_dbg(dev, "bit1 error\n");
> +		cf->data[2] |= CAN_ERR_PROT_BIT1;
> +		break;
> +	case LEC_BIT0_ERROR:
> +		netdev_dbg(dev, "bit0 error\n");
> +		cf->data[2] |= CAN_ERR_PROT_BIT0;
> +		break;
> +	case LEC_CRC_ERROR:
> +		netdev_dbg(dev, "CRC error\n");
> +		cf->data[2] |= (CAN_ERR_PROT_LOC_CRC_SEQ |
> +				CAN_ERR_PROT_LOC_CRC_DEL);
> +		break;
> +	default:
> +		break;
> +	}
> +
> +	/* set a LEC value so that we can check for updates later */
> +	d_can_write(priv, D_CAN_ES, LEC_UNUSED);
> +
> +	netif_receive_skb(skb);
> +	stats->rx_packets++;
> +	stats->rx_bytes += cf->can_dlc;
> +
> +	return 1;
> +}
> +
> +static int d_can_poll(struct napi_struct *napi, int quota)
> +{
> +	int work_done = 0;
> +	int lec_type = 0;
> +	struct net_device *dev = napi->dev;
> +	struct d_can_priv *priv = netdev_priv(dev);
> +
> +	if (!priv->irqstatus)
> +		goto end;
> +
> +	/* status events have the highest priority */
> +	if (priv->irqstatus == D_CAN_STATUS_INTERRUPT) {
> +		priv->current_status = d_can_read(priv, D_CAN_ES);
> +
> +		/* handle Tx/Rx events */
> +		if (priv->current_status & D_CAN_ES_TXOK)
> +			d_can_write(priv, D_CAN_ES,
> +					priv->current_status & ~D_CAN_ES_TXOK);
> +
> +		if (priv->current_status & D_CAN_ES_RXOK)
> +			d_can_write(priv, D_CAN_ES,
> +					priv->current_status & ~D_CAN_ES_RXOK);
> +
> +		/* handle state changes */
> +		if ((priv->current_status & D_CAN_ES_EWARN) &&
> +				(!(priv->last_status & D_CAN_ES_EWARN))) {
> +			netdev_dbg(dev, "entered error warning state\n");
> +			work_done += d_can_handle_state_change(dev,
> +						ERROR_WARNING);
> +		}
> +		if ((priv->current_status & D_CAN_ES_EPASS) &&
> +				(!(priv->last_status & D_CAN_ES_EPASS))) {
> +			netdev_dbg(dev, "entered error passive state\n");
> +			work_done += d_can_handle_state_change(dev,
> +						ERROR_PASSIVE);
> +		}
> +		if ((priv->current_status & D_CAN_ES_BOFF) &&
> +				(!(priv->last_status & D_CAN_ES_BOFF))) {
> +			netdev_dbg(dev, "entered bus off state\n");
> +			work_done += d_can_handle_state_change(dev, BUS_OFF);
> +		}
> +
> +		/* handle bus recovery events */
> +		if ((!(priv->current_status & D_CAN_ES_BOFF)) &&
> +				(priv->last_status & D_CAN_ES_BOFF)) {
> +			netdev_dbg(dev, "left bus off state\n");
> +			priv->can.state = CAN_STATE_ERROR_ACTIVE;
> +		}
> +		if ((!(priv->current_status & D_CAN_ES_EPASS)) &&
> +				(priv->last_status & D_CAN_ES_EPASS)) {
> +			netdev_dbg(dev, "left error passive state\n");
> +			priv->can.state = CAN_STATE_ERROR_ACTIVE;
> +		}
> +		priv->last_status = priv->current_status;
> +
> +		/* handle lec errors on the bus */
> +		lec_type = d_can_has_handle_berr(priv);
> +		if (lec_type)
> +			work_done += d_can_handle_bus_err(dev, lec_type);
> +	} else if ((priv->irqstatus >= D_CAN_MSG_OBJ_RX_FIRST) &&
> +			(priv->irqstatus <= D_CAN_MSG_OBJ_RX_LAST)) {
> +		/* handle events corresponding to receive message objects */
> +		work_done += d_can_do_rx_poll(dev, (quota - work_done));
> +	} else if ((priv->irqstatus >= D_CAN_MSG_OBJ_TX_FIRST) &&
> +			(priv->irqstatus <= D_CAN_MSG_OBJ_TX_LAST)) {
> +		/* handle events corresponding to transmit message objects */
> +		d_can_do_tx(dev);
> +	}
> +end:
> +	if (work_done < quota) {
> +		napi_complete(napi);
> +		d_can_interrupts(priv, D_CAN_ENABLE_ALL_INTERRUPTS);
> +	}
> +	return work_done;
> +}
> +
> +static irqreturn_t d_can_isr(int irq, void *dev_id)
> +{
> +	struct net_device *dev = (struct net_device *)dev_id;
> +	struct d_can_priv *priv = netdev_priv(dev);
> +
> +	priv->irqstatus = d_can_read(priv, D_CAN_INT);
> +	if (!priv->irqstatus)
> +		return IRQ_NONE;
> +
> +	/* disable all interrupts and schedule the NAPI */
> +	d_can_interrupts(priv, D_CAN_DISABLE_ALL_INTERRUPTS);
> +	napi_schedule(&priv->napi);
> +
> +	return IRQ_HANDLED;
> +}
> +
> +static int d_can_open(struct net_device *ndev)
> +{
> +	int err;
> +	struct d_can_priv *priv = netdev_priv(ndev);
> +
> +	/* Open common can device */
> +	err = open_candev(ndev);
> +	if (err) {
> +		netdev_err(ndev, "open_candev() failed %d\n", err);
> +		return err;
> +	}
> +
> +	err = request_irq(ndev->irq, &d_can_isr, IRQF_SHARED, ndev->name,
> +				ndev);
> +	if (err) {
> +		netdev_err(ndev, "failed to request MO_ES interrupt\n");
> +		goto exit_close_candev;
> +	}
> +
> +	/* start the d_can controller */
> +	d_can_start(ndev);
> +	napi_enable(&priv->napi);
> +	netif_start_queue(ndev);
> +	priv->is_opened = true;
> +
> +	return 0;
> +exit_close_candev:
> +	close_candev(ndev);
> +	return err;
> +}
> +
> +static int d_can_close(struct net_device *ndev)
> +{
> +	struct d_can_priv *priv = netdev_priv(ndev);
> +
> +	netif_stop_queue(ndev);
> +	napi_disable(&priv->napi);
> +	d_can_stop(ndev);
> +	free_irq(ndev->irq, ndev);
> +	close_candev(ndev);
> +	priv->is_opened = false;
> +
> +	return 0;
> +}
> +
> +static void d_can_reset_ram(struct d_can_priv *d_can, unsigned int instance,
> +					unsigned int enable)
> +{
> +	if (d_can->ram_init)
> +		d_can->ram_init(instance, enable);
> +	/* Give some time delay for DCAN RAM initialization */
> +	udelay(1);
> +}
> +
> +static struct net_device *alloc_d_can_dev(unsigned int num_objs)
> +{
> +	struct net_device *dev;
> +	struct d_can_priv *priv;
> +
> +	dev = alloc_candev(sizeof(struct d_can_priv), num_objs/2);
> +	if (!dev)
> +		return NULL;
> +
> +	priv = netdev_priv(dev);
> +	netif_napi_add(dev, &priv->napi, d_can_poll, num_objs/2);
> +
> +	priv->dev = dev;
> +	priv->can.bittiming_const = &d_can_bittiming_const;
> +	priv->can.do_set_mode = d_can_set_mode;
> +	priv->can.do_get_berr_counter = d_can_get_berr_counter;
> +	priv->can.ctrlmode_supported = (CAN_CTRLMODE_LOOPBACK |
> +					CAN_CTRLMODE_LISTENONLY |
> +					CAN_CTRLMODE_BERR_REPORTING |
> +					CAN_CTRLMODE_3_SAMPLES);
> +	return dev;
> +}
> +
> +static void free_d_can_dev(struct net_device *dev)
> +{
> +	free_candev(dev);
> +}
> +
> +static const struct net_device_ops d_can_netdev_ops = {
> +	.ndo_open	= d_can_open,
> +	.ndo_stop	= d_can_close,
> +	.ndo_start_xmit	= d_can_start_xmit,
> +};
> +
> +static int register_d_can_dev(struct net_device *dev)
> +{
> +	/* we support local echo */
> +	dev->flags |= IFF_ECHO;
> +	dev->netdev_ops = &d_can_netdev_ops;
> +	return register_candev(dev);
> +}
> +
> +static void unregister_d_can_dev(struct net_device *dev)
> +{
> +	struct d_can_priv *priv = netdev_priv(dev);
> +
> +	d_can_interrupts(priv, D_CAN_DISABLE_ALL_INTERRUPTS);
> +	unregister_candev(dev);
> +}
> +
> +static int __devinit d_can_plat_probe(struct platform_device *pdev)
> +{
> +	int ret = 0;
> +	void __iomem *addr;
> +	struct net_device *ndev;
> +	struct d_can_priv *priv;
> +	struct resource *mem, *irq;
> +	struct d_can_platform_data *pdata;
> +	struct clk *fck;
> +
> +	pdata = pdev->dev.platform_data;
> +	if (!pdata) {
> +		dev_err(&pdev->dev, "No platform data\n");
> +		goto exit;
> +	}
> +
> +	/* get the platform data */
> +	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	if (!mem) {
> +		ret = -ENODEV;
> +		dev_err(&pdev->dev, "No mem resource\n");
> +		goto exit;
> +	}
> +	irq = platform_get_resource_byname(pdev, IORESOURCE_IRQ, "d_can_ms");
> +	if (!irq) {
> +		dev_err(&pdev->dev, "No irq resource\n");
> +		goto exit;
> +	}
> +	if (!request_mem_region(mem->start, resource_size(mem),
> +				D_CAN_DRV_NAME)) {
> +		dev_err(&pdev->dev, "resource unavailable\n");
> +		ret = -EBUSY;
> +		goto exit;
> +	}
> +	addr = ioremap(mem->start, resource_size(mem));
> +	if (!addr) {
> +		dev_err(&pdev->dev, "ioremap failed\n");
> +		ret = -ENOMEM;
> +		goto exit_release_mem;
> +	}
> +
> +	/* allocate the d_can device */
> +	ndev = alloc_d_can_dev(pdata->num_of_msg_objs);
> +	if (!ndev) {
> +		dev_err(&pdev->dev, "alloc_d_can_dev failed\n");
> +		ret = -ENOMEM;
> +		goto exit_iounmap;
> +	}
> +	fck = clk_get(&pdev->dev, "fck");
> +	if (IS_ERR(fck)) {
> +		dev_err(&pdev->dev, "fck is not found\n");
> +		ret = -ENODEV;
> +		goto exit_free_ndev;
> +	}
> +
> +	priv = netdev_priv(ndev);
> +	priv->base = addr;
> +	priv->can.clock.freq = clk_get_rate(fck);
> +	priv->ram_init = pdata->ram_init;
> +	priv->is_opened = false;
> +
> +	ndev->irq = irq->start;
> +	platform_set_drvdata(pdev, ndev);
> +	SET_NETDEV_DEV(ndev, &pdev->dev);
> +
> +	pm_runtime_enable(&pdev->dev);
> +	pm_runtime_get_sync(&pdev->dev);
> +
> +	ret = register_d_can_dev(ndev);
> +	if (ret) {
> +		dev_err(&pdev->dev, "registering %s failed (err = %d)\n",
> +				D_CAN_DRV_NAME, ret);
> +		goto exit_free_device;
> +	}
> +
> +	/* Initialize DCAN RAM */
> +	d_can_reset_ram(priv, pdev->id, 1);
> +
> +	dev_info(&pdev->dev, "device registered (irq = %d)\n", ndev->irq);
> +	return 0;
> +exit_free_device:
> +	platform_set_drvdata(pdev, NULL);
> +	pm_runtime_disable(&pdev->dev);
> +	clk_put(fck);
> +exit_free_ndev:
> +	free_d_can_dev(ndev);
> +exit_iounmap:
> +	iounmap(addr);
> +exit_release_mem:
> +	release_mem_region(mem->start, resource_size(mem));
> +exit:
> +	dev_err(&pdev->dev, "probe failed\n");
> +	return ret;
> +}
> +
> +static int __devexit d_can_plat_remove(struct platform_device *pdev)
> +{
> +	struct net_device *ndev = platform_get_drvdata(pdev);
> +	struct d_can_priv *priv = netdev_priv(ndev);
> +	struct resource *mem;
> +
> +	d_can_reset_ram(priv, pdev->id, 0);
> +
> +	unregister_d_can_dev(ndev);
> +	platform_set_drvdata(pdev, NULL);
> +
> +	free_d_can_dev(ndev);
> +	iounmap(priv->base);
> +
> +	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	release_mem_region(mem->start, resource_size(mem));
> +
> +	pm_runtime_put_sync(&pdev->dev);
> +	pm_runtime_disable(&pdev->dev);
> +
> +	return 0;
> +}
> +
> +#ifdef CONFIG_PM
> +static int d_can_suspend(struct platform_device *pdev, pm_message_t state)
> +{
> +	unsigned long time_out;
> +	struct net_device *ndev = platform_get_drvdata(pdev);
> +	struct d_can_priv *priv = netdev_priv(ndev);
> +
> +	if (netif_running(ndev)) {
> +		netif_stop_queue(ndev);
> +		netif_device_detach(ndev);
> +	}
> +
> +	d_can_set_bit(priv, D_CAN_CTL, D_CAN_CTL_PDR);
> +
> +	/* PDA bit will become high only when all the pending
> +	 * transfers are completed */
> +	time_out = jiffies + msecs_to_jiffies(D_CAN_TIMEOUT_MS);
> +	while (!d_can_get_bit(priv, D_CAN_ES, D_CAN_ES_PDA) &&
> +				time_after(time_out, jiffies))
> +		cpu_relax();
> +
> +	if (time_after(jiffies, time_out)) {
> +		netdev_err(ndev, "Not entered power down mode\n");
> +		return -ETIMEDOUT;
> +	}
> +
> +	if (priv->is_opened)
> +		d_can_stop(ndev);
> +
> +	priv->can.state = CAN_STATE_SLEEPING;
> +	/* De-initialize DCAN RAM */
> +	d_can_reset_ram(priv, pdev->id, 0);
> +	/* Disable the module */
> +	pm_runtime_put_sync(&pdev->dev);
> +	return 0;
> +}
> +
> +static int d_can_resume(struct platform_device *pdev)
> +{
> +	unsigned long time_out;
> +	struct net_device *ndev = platform_get_drvdata(pdev);
> +	struct d_can_priv *priv = netdev_priv(ndev);
> +
> +	/* Enable the module */
> +	pm_runtime_get_sync(&pdev->dev);
> +	/* Initialize DCAN RAM */
> +	d_can_reset_ram(priv, pdev->id, 1);
> +
> +	/* Brought back from power down mode */
> +	d_can_clear_bit(priv, D_CAN_CTL, D_CAN_CTL_PDR);
> +	d_can_clear_bit(priv, D_CAN_CTL, D_CAN_CTL_INIT);
> +
> +	/* Wait for the PDA bit to get clear */
> +	time_out = jiffies + msecs_to_jiffies(D_CAN_TIMEOUT_MS);
> +	while (d_can_get_bit(priv, D_CAN_ES, D_CAN_ES_PDA) &&
> +				time_after(time_out, jiffies))
> +		cpu_relax();
> +
> +	if (time_after(jiffies, time_out)) {
> +		netdev_err(ndev, "Not came out from power down mode\n");
> +		return -ETIMEDOUT;
> +	}
> +
> +	if (priv->is_opened)
> +		d_can_start(ndev);
> +
> +	priv->can.state = CAN_STATE_ERROR_ACTIVE;
> +
> +	if (netif_running(ndev)) {
> +		netif_device_attach(ndev);
> +		netif_start_queue(ndev);
> +	}
> +	return 0;
> +}
> +#else
> +#define d_can_suspend NULL
> +#define d_can_resume NULL
> +#endif
> +
> +static struct platform_driver d_can_plat_driver = {
> +	.driver = {
> +		.name	= D_CAN_DRV_NAME,
> +		.owner	= THIS_MODULE,
> +	},
> +	.probe		= d_can_plat_probe,
> +	.remove		= __devexit_p(d_can_plat_remove),
> +	.suspend	= d_can_suspend,
> +	.resume		= d_can_resume,
> +};
> +
> +static int __init d_can_plat_init(void)
> +{
> +	return platform_driver_register(&d_can_plat_driver);
> +}
> +module_init(d_can_plat_init);
> +
> +static void __exit d_can_plat_exit(void)
> +{
> +	platform_driver_unregister(&d_can_plat_driver);
> +}
> +module_exit(d_can_plat_exit);
> +
> +MODULE_AUTHOR("AnilKumar Ch <anilkumar@ti.com>");
> +MODULE_LICENSE("GPL v2");
> +MODULE_VERSION(D_CAN_VERSION);
> +MODULE_DESCRIPTION(D_CAN_DRV_DESC);
> diff --git a/include/linux/can/platform/d_can.h b/include/linux/can/platform/d_can.h
> new file mode 100644
> index 0000000..b6f2a3f
> --- /dev/null
> +++ b/include/linux/can/platform/d_can.h
> @@ -0,0 +1,40 @@
> +/*
> + * D_CAN controller driver platform header
> + *
> + * Copyright (C) 2012 Texas Instruments Incorporated - http://www.ti.com/
> + *
> + * Bosch D_CAN controller is compliant to CAN protocol version 2.0 part A and B.
> + * Bosch D_CAN user manual can be obtained from:
> + * http://www.semiconductors.bosch.de/media/en/pdf/ipmodules_1/can/
> + * d_can_users_manual_111.pdf
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public License as
> + * published by the Free Software Foundation version 2.
> + *
> + * This program is distributed "as is" WITHOUT ANY WARRANTY of any
> + * kind, whether express or implied; without even the implied warranty
> + * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + */
> +
> +#ifndef __CAN_PLATFORM_TI_D_CAN_H__
> +#define __CAN_PLATFORM_TI_D_CAN_H__
> +
> +/**
> + * struct d_can_platform_data - DCAN Platform Data
> + *
> + * @num_of_msg_objs:	Number of message objects
> + * @dma_support:	DMA support is required/not
> + * @ram_init:		DCAN RAM initialization
> + *
> + * Platform data structure to get all platform specific settings.
> + * this structure also accounts the fact that the IP may have different
> + * RAM and mailbox offsets for different SOC's
> + */
> +struct d_can_platform_data {
> +	unsigned int num_of_msg_objs;
> +	bool dma_support;
> +	void (*ram_init) (unsigned int instance, unsigned int eanble);
> +};
> +#endif

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Marc Kleine-Budde - April 3, 2012, 12:49 p.m.
On 04/03/2012 02:44 PM, Wolfgang Grandegger wrote:
> On 04/03/2012 02:32 PM, AnilKumar Ch wrote:
>> This patch adds the support for Bosch D_CAN controller.
>>
>> Bosch D_CAN controller is a full-CAN implementation compliant to
>> CAN protocol version 2.0 part A and B. Bosch D_CAN user manual
>> can be obtained from: http://www.semiconductors.bosch.de/media/
>> en/pdf/ipmodules_1/can/d_can_users_manual_111.pdf
>>
>> D_CAN device is used on many SoCs like AM335x, DM8148 and DM813x
>> EVMs from TI, D_CAN details on AM335x can be accessed from:
>> http://www.ti.com/lit/ug/spruh73c/spruh73c.pdf
>>
>> D_CAN can be configurable for 16, 32, 64 and 128 message objects.
>> The driver implementation is based on 64 message objects.
>>
>> Following are the design choices made while writing the controller
>> driver:
>> 1. Interface Register set IF0 has be used for receive and IF1 is
>>    used for transmit message objects.
>> 2. Out of the total Message objects available, half of it are kept
>>    aside for RX purposes and the rest for TX purposes.
>> 3. NAPI implementation is such that both the TX and RX paths
>>    functions in polling mode.
>>
>> Signed-off-by: AnilKumar Ch <anilkumar@ti.com>
> 
> Please explain why this CAN controller cannot be handled by the existing
> C_CAN driver, eventually with some extensions. The register layout seems
> almost identical, at least.

ACK.

Have a look at the recent at91_can driver. It has been improved to work
with a flexible number of message objects.

Marc
AnilKumar Chimata - April 3, 2012, 1:41 p.m.
Hi Wolfgang,

Thanks for reviewing the patch

On Tue, Apr 03, 2012 at 18:14:55, Wolfgang Grandegger wrote:
> On 04/03/2012 02:32 PM, AnilKumar Ch wrote:
> > This patch adds the support for Bosch D_CAN controller.
> > 
> > Bosch D_CAN controller is a full-CAN implementation compliant to
> > CAN protocol version 2.0 part A and B. Bosch D_CAN user manual
> > can be obtained from: http://www.semiconductors.bosch.de/media/
> > en/pdf/ipmodules_1/can/d_can_users_manual_111.pdf
> > 
> > D_CAN device is used on many SoCs like AM335x, DM8148 and DM813x
> > EVMs from TI, D_CAN details on AM335x can be accessed from:
> > http://www.ti.com/lit/ug/spruh73c/spruh73c.pdf
> > 
> > D_CAN can be configurable for 16, 32, 64 and 128 message objects.
> > The driver implementation is based on 64 message objects.
> > 
> > Following are the design choices made while writing the controller
> > driver:
> > 1. Interface Register set IF0 has be used for receive and IF1 is
> >    used for transmit message objects.
> > 2. Out of the total Message objects available, half of it are kept
> >    aside for RX purposes and the rest for TX purposes.
> > 3. NAPI implementation is such that both the TX and RX paths
> >    functions in polling mode.
> > 
> > Signed-off-by: AnilKumar Ch <anilkumar@ti.com>
> 
> Please explain why this CAN controller cannot be handled by the existing
> C_CAN driver, eventually with some extensions. The register layout seems
> almost identical, at least.
> 
> Wolfgang.
> 

These are the some of the pointers I can say, why I had gone for separate
file instead of existing driver:
* In case of D_CAN driver we can see all the registers are 32bit length
  but in case of C_CAN registers are in 16bit length.
* Some of the registers, bit masks are different, so we have to add
  checks on every API for differentiating the kind of device
* In case of D_CAN we have some extra features like direct message RAM
  access, DMA support, TX/RX pins can be used as GPIO lines (if applicable),
  more interrupt lines and three sets of interface registers.
* Wait timings while init bit set/reset during bit-timing initialization
  are different in both the cases
* bittiming configurations are different.

Thanks
AnilKumar
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Marc Kleine-Budde - April 3, 2012, 1:49 p.m.
On 04/03/2012 03:41 PM, AnilKumar, Chimata wrote:
> Hi Wolfgang,
> 
> Thanks for reviewing the patch
> 
> On Tue, Apr 03, 2012 at 18:14:55, Wolfgang Grandegger wrote:
>> On 04/03/2012 02:32 PM, AnilKumar Ch wrote:
>>> This patch adds the support for Bosch D_CAN controller.
>>>
>>> Bosch D_CAN controller is a full-CAN implementation compliant to
>>> CAN protocol version 2.0 part A and B. Bosch D_CAN user manual
>>> can be obtained from: http://www.semiconductors.bosch.de/media/
>>> en/pdf/ipmodules_1/can/d_can_users_manual_111.pdf
>>>
>>> D_CAN device is used on many SoCs like AM335x, DM8148 and DM813x
>>> EVMs from TI, D_CAN details on AM335x can be accessed from:
>>> http://www.ti.com/lit/ug/spruh73c/spruh73c.pdf
>>>
>>> D_CAN can be configurable for 16, 32, 64 and 128 message objects.
>>> The driver implementation is based on 64 message objects.
>>>
>>> Following are the design choices made while writing the controller
>>> driver:
>>> 1. Interface Register set IF0 has be used for receive and IF1 is
>>>    used for transmit message objects.
>>> 2. Out of the total Message objects available, half of it are kept
>>>    aside for RX purposes and the rest for TX purposes.
>>> 3. NAPI implementation is such that both the TX and RX paths
>>>    functions in polling mode.
>>>
>>> Signed-off-by: AnilKumar Ch <anilkumar@ti.com>
>>
>> Please explain why this CAN controller cannot be handled by the existing
>> C_CAN driver, eventually with some extensions. The register layout seems
>> almost identical, at least.
>>
>> Wolfgang.
>>
> 
> These are the some of the pointers I can say, why I had gone for separate
> file instead of existing driver:
> * In case of D_CAN driver we can see all the registers are 32bit length
>   but in case of C_CAN registers are in 16bit length.

How many bits in these 32 bit registers are used?

> * Some of the registers, bit masks are different, so we have to add
>   checks on every API for differentiating the kind of device

Which registers are this? Can you give us an example?

> * In case of D_CAN we have some extra features like direct message RAM
>   access, DMA support, TX/RX pins can be used as GPIO lines (if applicable),
>   more interrupt lines and three sets of interface registers.

Which of these features are used in you driver?

> * Wait timings while init bit set/reset during bit-timing initialization
>   are different in both the cases

That's not the hot code path, so some ifs shouldn't hurt.

> * bittiming configurations are different.

see above.

Marc
AnilKumar Chimata - April 3, 2012, 2:29 p.m.
On Tue, Apr 03, 2012 at 19:19:32, Marc Kleine-Budde wrote:
> On 04/03/2012 03:41 PM, AnilKumar, Chimata wrote:
> > Hi Wolfgang,
> > 
> > Thanks for reviewing the patch
> > 
> > On Tue, Apr 03, 2012 at 18:14:55, Wolfgang Grandegger wrote:
> >> On 04/03/2012 02:32 PM, AnilKumar Ch wrote:
> >>> This patch adds the support for Bosch D_CAN controller.
> >>>
> >>> Bosch D_CAN controller is a full-CAN implementation compliant to
> >>> CAN protocol version 2.0 part A and B. Bosch D_CAN user manual
> >>> can be obtained from: http://www.semiconductors.bosch.de/media/
> >>> en/pdf/ipmodules_1/can/d_can_users_manual_111.pdf
> >>>
> >>> D_CAN device is used on many SoCs like AM335x, DM8148 and DM813x
> >>> EVMs from TI, D_CAN details on AM335x can be accessed from:
> >>> http://www.ti.com/lit/ug/spruh73c/spruh73c.pdf
> >>>
> >>> D_CAN can be configurable for 16, 32, 64 and 128 message objects.
> >>> The driver implementation is based on 64 message objects.
> >>>
> >>> Following are the design choices made while writing the controller
> >>> driver:
> >>> 1. Interface Register set IF0 has be used for receive and IF1 is
> >>>    used for transmit message objects.
> >>> 2. Out of the total Message objects available, half of it are kept
> >>>    aside for RX purposes and the rest for TX purposes.
> >>> 3. NAPI implementation is such that both the TX and RX paths
> >>>    functions in polling mode.
> >>>
> >>> Signed-off-by: AnilKumar Ch <anilkumar@ti.com>
> >>
> >> Please explain why this CAN controller cannot be handled by the existing
> >> C_CAN driver, eventually with some extensions. The register layout seems
> >> almost identical, at least.
> >>
> >> Wolfgang.
> >>
> > 
> > These are the some of the pointers I can say, why I had gone for separate
> > file instead of existing driver:
> > * In case of D_CAN driver we can see all the registers are 32bit length
> >   but in case of C_CAN registers are in 16bit length.
> 
> How many bits in these 32 bit registers are used?

In some cases (D_CAN_TXRQ, D_CAN_INTPND, D_CAN_MSGVAL) I have used all the
bits, in some cases used few bits.

Roughly I can say that its (higher 16bits) % of usages is similar as compare
to 16bits 

While checking the status of TXRequest registers and INT pending register,
which is a hot code path, we have to put if checks for register access.

> 
> > * Some of the registers, bit masks are different, so we have to add
> >   checks on every API for differentiating the kind of device
> 
> Which registers are this? Can you give us an example?

I am pointing out some of the resisters
* Single registers in case of D_CAN but multiple register in case of C_CAN
  So masks will change MASK, ARB, INTPND
* D_CAN_IFCMD is the combination of COMM request and COMM mask registers

> 
> > * In case of D_CAN we have some extra features like direct message RAM
> >   access, DMA support, TX/RX pins can be used as GPIO lines (if applicable),
> >   more interrupt lines and three sets of interface registers.
> 
> Which of these features are used in you driver?

Right now I added only CAN functionality, in that I am using two set
of interface registers (0 and 1).

Based on other features status register are extended, we have to handle those
as well.

> 
> > * Wait timings while init bit set/reset during bit-timing initialization
> >   are different in both the cases
> 
> That's not the hot code path, so some ifs shouldn't hurt.
> 
> > * bittiming configurations are different.
> 
> see above.
> 
> Marc
> -- 
> Pengutronix e.K.                  | Marc Kleine-Budde           |
> Industrial Linux Solutions        | Phone: +49-231-2826-924     |
> Vertretung West/Dortmund          | Fax:   +49-5121-206917-5555 |
> Amtsgericht Hildesheim, HRA 2686  | http://www.pengutronix.de   |
> 
> 

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Marc Kleine-Budde - April 3, 2012, 3:33 p.m.
On 04/03/2012 04:29 PM, AnilKumar, Chimata wrote:
>>>> Please explain why this CAN controller cannot be handled by the existing
>>>> C_CAN driver, eventually with some extensions. The register layout seems
>>>> almost identical, at least.
>>>>
>>>> Wolfgang.
>>>>
>>>
>>> These are the some of the pointers I can say, why I had gone for separate
>>> file instead of existing driver:
>>> * In case of D_CAN driver we can see all the registers are 32bit length
>>>   but in case of C_CAN registers are in 16bit length.
>>
>> How many bits in these 32 bit registers are used?
> 
> In some cases (D_CAN_TXRQ, D_CAN_INTPND, D_CAN_MSGVAL) I have used all the
> bits, in some cases used few bits.
> 
> Roughly I can say that its (higher 16bits) % of usages is similar as compare
> to 16bits 
> 
> While checking the status of TXRequest registers and INT pending register,
> which is a hot code path, we have to put if checks for register access.

The c_can already has a c_can_read_reg32() function. It's for example
used in the rx_poll function. You can make it a function pointer (i.e.
pric->read_reg32()) for easy abstraction.

>>> * Some of the registers, bit masks are different, so we have to add
>>>   checks on every API for differentiating the kind of device
>>
>> Which registers are this? Can you give us an example?
> 
> I am pointing out some of the resisters
> * Single registers in case of D_CAN but multiple register in case of C_CAN
>   So masks will change MASK, ARB, INTPND
> * D_CAN_IFCMD is the combination of COMM request and COMM mask registers

Maybe you can use the read_reg32 function on both c_can and d_can.

regards, Marc
Oliver Hartkopp - April 3, 2012, 3:54 p.m.
On 03.04.2012 14:39, AnilKumar, Chimata wrote:

> Hi All,
> 
> Subject line of this patch should be
> "ARM: CAN: d_can: Add support for Bosch D_CAN controller"


No, the d_can IP core is generally not limited to ARM.

	"can: Add support for Bosch D_CAN controller"

would be perfectly fine.

The correct way is:

1. post your new CAN driver to linux-can ML
2. When the major reviews & style fixes are done and the driver is fit for
mainline you can post it on ti-omap ML too

But an initial cross-posting of this CAN driver to netdev ML and linux-kernel
ML does not help anyone - it only increases traffic & confusion.

See MAINTAINERS:

http://lxr.linux.no/#linux+v3.3.1/MAINTAINERS#L1710

Thanks for following these hints,
Oliver
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AnilKumar Chimata - April 3, 2012, 3:58 p.m.
On Tue, Apr 03, 2012 at 21:03:40, Marc Kleine-Budde wrote:
> On 04/03/2012 04:29 PM, AnilKumar, Chimata wrote:
> >>>> Please explain why this CAN controller cannot be handled by the existing
> >>>> C_CAN driver, eventually with some extensions. The register layout seems
> >>>> almost identical, at least.
> >>>>
> >>>> Wolfgang.
> >>>>
> >>>
> >>> These are the some of the pointers I can say, why I had gone for separate
> >>> file instead of existing driver:
> >>> * In case of D_CAN driver we can see all the registers are 32bit length
> >>>   but in case of C_CAN registers are in 16bit length.
> >>
> >> How many bits in these 32 bit registers are used?
> > 
> > In some cases (D_CAN_TXRQ, D_CAN_INTPND, D_CAN_MSGVAL) I have used all the
> > bits, in some cases used few bits.
> > 
> > Roughly I can say that its (higher 16bits) % of usages is similar as compare
> > to 16bits 
> > 
> > While checking the status of TXRequest registers and INT pending register,
> > which is a hot code path, we have to put if checks for register access.
> 
> The c_can already has a c_can_read_reg32() function. It's for example
> used in the rx_poll function. You can make it a function pointer (i.e.
> pric->read_reg32()) for easy abstraction.

This won't fit for D_CAN case because offsets are different in c_can compared
to d_can. For example if I read CONTROL_REG register (0x0) in case of d_can,
which will read only control register. In case of c_can it will read
CONTROL_REG + STATUS register values in single read

> 
> >>> * Some of the registers, bit masks are different, so we have to add
> >>>   checks on every API for differentiating the kind of device
> >>
> >> Which registers are this? Can you give us an example?
> > 
> > I am pointing out some of the resisters
> > * Single registers in case of D_CAN but multiple register in case of C_CAN
> >   So masks will change MASK, ARB, INTPND
> > * D_CAN_IFCMD is the combination of COMM request and COMM mask registers
> 
> Maybe you can use the read_reg32 function on both c_can and d_can.

Above comment applies here as well

> 
> regards, Marc
> 
> -- 
> Pengutronix e.K.                  | Marc Kleine-Budde           |
> Industrial Linux Solutions        | Phone: +49-231-2826-924     |
> Vertretung West/Dortmund          | Fax:   +49-5121-206917-5555 |
> Amtsgericht Hildesheim, HRA 2686  | http://www.pengutronix.de   |
> 
> 

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AnilKumar Chimata - April 3, 2012, 6:07 p.m.
Hi Oliver,

Thanks for the comments,

On Tue, Apr 03, 2012 at 21:24:23, Oliver Hartkopp wrote:
> On 03.04.2012 14:39, AnilKumar, Chimata wrote:
>
> > Hi All,
> >
> > Subject line of this patch should be
> > "ARM: CAN: d_can: Add support for Bosch D_CAN controller"
>
>
> No, the d_can IP core is generally not limited to ARM.
>
>       "can: Add support for Bosch D_CAN controller"
>
> would be perfectly fine.

Agree, I will change the subject line in my next version of patch

>
> The correct way is:
>
> 1. post your new CAN driver to linux-can ML
> 2. When the major reviews & style fixes are done and the driver is fit for
> mainline you can post it on ti-omap ML too
>
> But an initial cross-posting of this CAN driver to netdev ML and linux-kernel
> ML does not help anyone - it only increases traffic & confusion
>

It's true, I will take care from next time onwards

Thanks
AnilKumar
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Bhupesh Sharma - April 4, 2012, 3:43 a.m.
> -----Original Message-----
> From: linux-can-owner@vger.kernel.org [mailto:linux-can-
> owner@vger.kernel.org] On Behalf Of AnilKumar, Chimata
> Sent: Tuesday, April 03, 2012 9:28 PM
> To: Marc Kleine-Budde
> Cc: Wolfgang Grandegger; socketcan@hartkopp.net; m.kleine-
> budde@pengutronix.de; linux-can@vger.kernel.org;
> netdev@vger.kernel.org; linux-omap@vger.kernel.org; linux-
> kernel@vger.kernel.org; Gole, Anant; Nori, Sekhar
> Subject: RE: [PATCH] ARM: OMAP: AM33XX: CAN: d_can: Add support for
> Bosch D_CAN controller
> 
> On Tue, Apr 03, 2012 at 21:03:40, Marc Kleine-Budde wrote:
> > On 04/03/2012 04:29 PM, AnilKumar, Chimata wrote:
> > >>>> Please explain why this CAN controller cannot be handled by the
> existing
> > >>>> C_CAN driver, eventually with some extensions. The register
> layout seems
> > >>>> almost identical, at least.
> > >>>>
> > >>>> Wolfgang.
> > >>>>
> > >>>
> > >>> These are the some of the pointers I can say, why I had gone for
> separate
> > >>> file instead of existing driver:
> > >>> * In case of D_CAN driver we can see all the registers are 32bit
> length
> > >>>   but in case of C_CAN registers are in 16bit length.
> > >>
> > >> How many bits in these 32 bit registers are used?
> > >
> > > In some cases (D_CAN_TXRQ, D_CAN_INTPND, D_CAN_MSGVAL) I have used
> all the
> > > bits, in some cases used few bits.
> > >
> > > Roughly I can say that its (higher 16bits) % of usages is similar
> as compare
> > > to 16bits
> > >
> > > While checking the status of TXRequest registers and INT pending
> register,
> > > which is a hot code path, we have to put if checks for register
> access.
> >
> > The c_can already has a c_can_read_reg32() function. It's for example
> > used in the rx_poll function. You can make it a function pointer
> (i.e.
> > pric->read_reg32()) for easy abstraction.
> 
> This won't fit for D_CAN case because offsets are different in c_can
> compared
> to d_can. For example if I read CONTROL_REG register (0x0) in case of
> d_can,
> which will read only control register. In case of c_can it will read
> CONTROL_REG + STATUS register values in single read

C_CAN core has both 16-bit as well as 32-bit registers.
While the registers like NEWDATA and INTPND are 32-bit the others
like Control and Status are 16-bit.

These cases are handled by the present C_CAN driver already.
If you will see the C_CAN driver then you will see that the normal
read/write operations are 16-bit whereas a special variant is provided
for 32-bit access.

Are you sure you cannot use them as it is?

> >
> > >>> * Some of the registers, bit masks are different, so we have to
> add
> > >>>   checks on every API for differentiating the kind of device
> > >>
> > >> Which registers are this? Can you give us an example?
> > >
> > > I am pointing out some of the resisters
> > > * Single registers in case of D_CAN but multiple register in case
> of C_CAN
> > >   So masks will change MASK, ARB, INTPND
> > > * D_CAN_IFCMD is the combination of COMM request and COMM mask
> registers
> >
> > Maybe you can use the read_reg32 function on both c_can and d_can.
> 
> Above comment applies here as well
> 

This can be easily handled. I have worked on several drivers that do that.
See for example the STMPE multi-function device driver (MFD), here [1]

There are various variants of STMPE devices (like STMPE801 etc..) and they
can be handled by using a common driver and passing different platform data
intelligently that provides specific handling for a specific STMPE device.

Regards,
Bhupesh

[1] http://lxr.linux.no/linux+v3.3.1/drivers/mfd/stmpe.c

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Wolfgang Grandegger - April 4, 2012, 4:21 p.m.
On 04/03/2012 05:58 PM, AnilKumar, Chimata wrote:
> On Tue, Apr 03, 2012 at 21:03:40, Marc Kleine-Budde wrote:
>> On 04/03/2012 04:29 PM, AnilKumar, Chimata wrote:
>>>>>> Please explain why this CAN controller cannot be handled by the existing
>>>>>> C_CAN driver, eventually with some extensions. The register layout seems
>>>>>> almost identical, at least.
>>>>>>
>>>>>> Wolfgang.
>>>>>>
>>>>>
>>>>> These are the some of the pointers I can say, why I had gone for separate
>>>>> file instead of existing driver:
>>>>> * In case of D_CAN driver we can see all the registers are 32bit length
>>>>>   but in case of C_CAN registers are in 16bit length.
>>>>
>>>> How many bits in these 32 bit registers are used?
>>>
>>> In some cases (D_CAN_TXRQ, D_CAN_INTPND, D_CAN_MSGVAL) I have used all the
>>> bits, in some cases used few bits.
>>>
>>> Roughly I can say that its (higher 16bits) % of usages is similar as compare
>>> to 16bits 
>>>
>>> While checking the status of TXRequest registers and INT pending register,
>>> which is a hot code path, we have to put if checks for register access.
>>
>> The c_can already has a c_can_read_reg32() function. It's for example
>> used in the rx_poll function. You can make it a function pointer (i.e.
>> pric->read_reg32()) for easy abstraction.
> 
> This won't fit for D_CAN case because offsets are different in c_can compared
> to d_can. For example if I read CONTROL_REG register (0x0) in case of d_can,
> which will read only control register. In case of c_can it will read
> CONTROL_REG + STATUS register values in single read
> 
>>
>>>>> * Some of the registers, bit masks are different, so we have to add
>>>>>   checks on every API for differentiating the kind of device
>>>>
>>>> Which registers are this? Can you give us an example?
>>>
>>> I am pointing out some of the resisters
>>> * Single registers in case of D_CAN but multiple register in case of C_CAN
>>>   So masks will change MASK, ARB, INTPND
>>> * D_CAN_IFCMD is the combination of COMM request and COMM mask registers
>>
>> Maybe you can use the read_reg32 function on both c_can and d_can.
> 
> Above comment applies here as well

I did look into the manual. Unfortunately, a direct mapping of the C_CAN
to the D_CAN registers seems not possible. It's not just a different
alignment but sometimes two 16-bit C_CAN registers are folded into *one*
32-bit D_CAN register. Therefore we need something more clever, e.g.
using a separate struct or union or handling those register separately.
I still think, if feasible, we should avoid an extra driver for the
D_CAN controller, also because we sooner than later need the same
infrastructure (register_c_can_dev etc.).

Wolfgang.
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Patch

diff --git a/drivers/net/can/Kconfig b/drivers/net/can/Kconfig
index bb709fd..2529cba 100644
--- a/drivers/net/can/Kconfig
+++ b/drivers/net/can/Kconfig
@@ -68,6 +68,20 @@  config CAN_TI_HECC
 	  Driver for TI HECC (High End CAN Controller) module found on many
 	  TI devices. The device specifications are available from www.ti.com
 
+config CAN_D_CAN
+	tristate "Bosch D_CAN Controller"
+	depends on CAN_DEV
+	---help---
+	  This driver adds support for the D_CAN device found in
+	  many SoCs like am335x, dm814x and dm813x boards from TI.
+
+	  The device user guide can be accessed from
+	  http://www.semiconductors.bosch.de/media/en/pdf/ipmodules_1/
+	  can/d_can_users_manual_111.pdf
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called d_can.
+
 config CAN_MCP251X
 	tristate "Microchip MCP251x SPI CAN controllers"
 	depends on CAN_DEV && SPI && HAS_DMA
diff --git a/drivers/net/can/Makefile b/drivers/net/can/Makefile
index 938be37..4bd3a87 100644
--- a/drivers/net/can/Makefile
+++ b/drivers/net/can/Makefile
@@ -17,6 +17,7 @@  obj-$(CONFIG_CAN_C_CAN)		+= c_can/
 obj-$(CONFIG_CAN_CC770)		+= cc770/
 obj-$(CONFIG_CAN_AT91)		+= at91_can.o
 obj-$(CONFIG_CAN_TI_HECC)	+= ti_hecc.o
+obj-$(CONFIG_CAN_D_CAN)		+= d_can.o
 obj-$(CONFIG_CAN_MCP251X)	+= mcp251x.o
 obj-$(CONFIG_CAN_BFIN)		+= bfin_can.o
 obj-$(CONFIG_CAN_JANZ_ICAN3)	+= janz-ican3.o
diff --git a/drivers/net/can/d_can.c b/drivers/net/can/d_can.c
new file mode 100644
index 0000000..51e2986
--- /dev/null
+++ b/drivers/net/can/d_can.c
@@ -0,0 +1,1487 @@ 
+/*
+ * CAN bus driver for Bosch D_CAN controller
+ *
+ * Copyright (C) 2012 Texas Instruments Incorporated - http://www.ti.com/
+ *
+ * Borrowed from C_CAN driver
+ * Copyright (C) 2010 ST Microelectronics
+ * - Bhupesh Sharma <bhupesh.sharma@st.com>
+ *
+ * Borrowed heavily from the C_CAN driver originally written by:
+ * Copyright (C) 2007
+ * - Sascha Hauer, Marc Kleine-Budde, Pengutronix <s.hauer@pengutronix.de>
+ * - Simon Kallweit, intefo AG <simon.kallweit@intefo.ch>
+ *
+ * Bosch D_CAN controller is compliant to CAN protocol version 2.0 part A and B.
+ * Bosch D_CAN user manual can be obtained from:
+ * http://www.semiconductors.bosch.de/media/en/pdf/ipmodules_1/can/
+ * d_can_users_manual_111.pdf
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation version 2.
+ *
+ * This program is distributed "as is" WITHOUT ANY WARRANTY of any
+ * kind, whether express or implied; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/interrupt.h>
+#include <linux/netdevice.h>
+#include <linux/errno.h>
+#include <linux/skbuff.h>
+#include <linux/jiffies.h>
+#include <linux/pm_runtime.h>
+#include <linux/platform_device.h>
+#include <linux/clk.h>
+#include <linux/io.h>
+
+#include <linux/can/dev.h>
+#include <linux/can/error.h>
+#include <linux/can/platform/d_can.h>
+
+#define D_CAN_DRV_NAME	"d_can"
+#define D_CAN_VERSION	"1.0"
+#define D_CAN_DRV_DESC	"CAN bus driver for Bosch D_CAN controller " \
+			D_CAN_VERSION
+
+/* TI D_CAN module registers */
+#define D_CAN_CTL		0x0	/* CAN control register */
+#define D_CAN_ES		0x4	/* Error and status */
+#define D_CAN_PARITYERR_EOI	0x4	/* Parity error EOI */
+#define D_CAN_ERRC		0x8	/* Error counter */
+#define D_CAN_BTR		0xC	/* Bit timing */
+#define D_CAN_INT		0x10	/* Interrupt register */
+#define D_CAN_TEST		0x14	/* Test register */
+#define D_CAN_PERR		0x1C	/* Parity Error Code */
+#define D_CAN_ABOTR		0x80	/* Auto-Bus-On Time */
+#define D_CAN_TXRQ_X		0x84	/* Transmission Request X */
+#define D_CAN_TXRQ(n)		(0x88 + ((n) * 4)) /* Transmission request */
+#define D_CAN_NWDAT_X		0x98	/* New data X register */
+#define D_CAN_NWDAT(n)		(0x9C + ((n) * 4)) /* New data */
+#define D_CAN_INTPND_X		0xAC	/* Interrupt Pending X */
+#define D_CAN_INTPND(n)		(0xB0 + ((n) * 4)) /* Interrupt Pending */
+#define D_CAN_MSGVAL_X		0xC0		/* Message Valid X */
+#define D_CAN_MSGVAL(n)		(0xC4 + ((n) * 4)) /* Message Valid */
+#define D_CAN_INTMUX(n)		(0xD8 + ((n) * 4)) /* Interrupt Multiplexer */
+#define D_CAN_IFCMD(n)		(0x100 + ((n) * 0x20)) /* Command */
+#define D_CAN_IFMSK(n)		(0x104 + ((n) * 0x20)) /* Mask */
+#define D_CAN_IFARB(n)		(0x108 + ((n) * 0x20)) /* Arbitration */
+#define D_CAN_IFMCTL(n)		(0x10c + ((n) * 0x20)) /* Message ctl */
+#define D_CAN_IFDATA(n)		(0x110 + ((n) * 0x20)) /* DATA A */
+#define D_CAN_IFDATB(n)		(0x114 + ((n) * 0x20)) /* DATA B */
+#define D_CAN_IF3OBS		0x140	/* IF3 Observation */
+#define D_CAN_IF3UPD(n)		(0x160 + ((n) * 4)) /* Update enable */
+#define D_CAN_TIOC		0x1E0	/* CAN TX IO Control */
+#define D_CAN_RIOC		0x1E4	/* CAN RX IO Control */
+
+/* Control register Bit fields */
+#define D_CAN_CTL_WUBA		BIT(26)	/* Automatic wake-up on bus activity */
+#define D_CAN_CTL_PDR		BIT(24)	/* Request for local low power mode */
+#define D_CAN_CTL_DE3		BIT(20)	/* Enable DMA request line for IF3 */
+#define D_CAN_CTL_DE2		BIT(19)	/* Enable DMA request line for IF2 */
+#define D_CAN_CTL_DE1		BIT(18)	/* Enable DMA request line for IF1 */
+#define D_CAN_CTL_IE1		BIT(17)	/* Interrupt line 1 enable */
+#define D_CAN_CTL_INITDBG	BIT(16)	/* Init state for debug access */
+#define D_CAN_CTL_SWR		BIT(15)	/* S/W reset enable */
+#define D_CAN_CTL_PMD		(0xF << 10)	/* Parity on/off */
+#define D_CAN_CTL_ABO		BIT(9)	/* Auto bus on enable */
+#define D_CAN_CTL_IDS		BIT(8)	/* Interruption debug support enable */
+#define D_CAN_CTL_TEST		BIT(7)	/* Test mode enable */
+#define D_CAN_CTL_CCE		BIT(6)	/* Configuration change enable */
+#define D_CAN_CTL_DISABLE_AR	BIT(5)	/* Disable automatic retransmission */
+#define D_CAN_CTL_EIE		BIT(3)	/* Error interrupt enable */
+#define D_CAN_CTL_SIE		BIT(2)	/* Status change int enable */
+#define D_CAN_CTL_IE0		BIT(1)	/* Interrupt line 0 enable */
+#define D_CAN_CTL_INIT		BIT(0)	/* D_CAN initialization mode */
+
+/* D_CAN Error and Status and Parity Error EOI reg bit fields */
+#define D_CAN_ES_PDA		BIT(10)	/* Local power-down ACK */
+#define D_CAN_ES_WUP		BIT(9)	/* Wkae up pending */
+#define D_CAN_ES_PER		BIT(8)	/* Parity error detected */
+#define D_CAN_ES_BOFF		BIT(7)	/* Bus off state */
+#define D_CAN_ES_EWARN		BIT(6)	/* Warning state */
+#define D_CAN_ES_EPASS		BIT(5)	/* Error passive state */
+#define D_CAN_ES_RXOK		BIT(4)	/* Received a msg successfully */
+#define D_CAN_ES_TXOK		BIT(3)	/* Transmitted a msg successfully */
+#define D_CAN_ES_LEC_MASK	0x7	/* Last error code */
+
+/* Error counter reg bit fields */
+#define D_CAN_ERRC_RP_MASK	BIT(15)		/* Receive error passive */
+#define D_CAN_ERRC_REC_SHIFT	8
+#define D_CAN_ERRC_REC_MASK	(0x7F << 8)	/* Receive err counter */
+#define D_CAN_ERRC_TEC_MASK	(0xFF << 0)	/* Transmit err counter */
+
+/* Bit timing reg bit fields */
+#define D_CAN_BTR_BRPE_SHIFT	16		/* Baud rate prescaler ext */
+#define D_CAN_BTR_TSEG2_SHIFT	12		/* Time seg after smpl point */
+#define D_CAN_BTR_TSEG1_SHIFT	8		/* Time seg before smpl point */
+#define D_CAN_BTR_SJW_SHIFT	6		/* Syncronization jump width */
+#define D_CAN_BTR_BRP_SHIFT	0		/* Baud rate prescaler */
+
+/* D_CAN Test register bit fields */
+#define D_CAN_TEST_RDA		BIT(9)	/* RAM direct access enable */
+#define D_CAN_TEST_EXL		BIT(8)	/* External loopback mode */
+#define D_CAN_TEST_RX		BIT(7)	/* Monitors the reveive pin */
+#define D_CAN_TEST_TX		(0x3 << 5)	/* Control of CAN_TX pin */
+#define D_CAN_TEST_LBACK	BIT(4)	/* Loopback mode */
+#define D_CAN_TEST_SILENT	BIT(3)	/* Silent mdoe */
+
+/* D_CAN IF command reg bit fields */
+#define D_CAN_IF_CMD_WR		BIT(23)	/* Write/read */
+#define D_CAN_IF_CMD_MASK	BIT(22)	/* Access to mask bits */
+#define D_CAN_IF_CMD_ARB	BIT(21)	/* Access to arbitration bits */
+#define D_CAN_IF_CMD_CONTROL	BIT(20)	/* Acess to control bits */
+#define D_CAN_IF_CMD_CIP	BIT(19)	/* Clear int pending */
+#define D_CAN_IF_CMD_TXRQST	BIT(18)	/* Access transmission request */
+#define D_CAN_IF_CMD_DATAA	BIT(17)	/* Access to Data Bytes 0-3 */
+#define D_CAN_IF_CMD_DATAB	BIT(16)	/* Access to Data Bytes 4-7 */
+#define D_CAN_IF_CMD_BUSY	BIT(15)	/* Busy flag */
+#define D_CAN_IF_CMD_DAM	BIT(14)	/* Activation of DMA */
+#define D_CAN_IF_CMD_MN_MASK	0xFF	/* No. of msg's used for DMA T/F */
+#define D_CAN_IF_CMD_ALL	(D_CAN_IF_CMD_MASK | D_CAN_IF_CMD_ARB | \
+				D_CAN_IF_CMD_CONTROL | D_CAN_IF_CMD_TXRQST | \
+				D_CAN_IF_CMD_DATAA | D_CAN_IF_CMD_DATAB)
+
+/* D_CAN IF mask reg bit fields */
+#define D_CAN_IF_MASK_MX	BIT(31)	/* Mask Extended Identifier */
+#define D_CAN_IF_MASK_MD	BIT(30)	/* Mask Message direction */
+
+/* D_CAN IF Arbitration */
+#define D_CAN_IF_ARB_MSGVAL	BIT(31)	/* Message Vaild */
+#define D_CAN_IF_ARB_MSGXTD	BIT(30)	/* Extended Identifier 0-11 1-29 */
+#define D_CAN_IF_ARB_DIR_XMIT	BIT(29) /* Message direction 0-R 1-T */
+
+/* D_CAN IF Message control */
+#define D_CAN_IF_MCTL_NEWDAT	BIT(15)	/* New data available */
+#define D_CAN_IF_MCTL_MSGLST	BIT(14)	/* Message lost, only for receive */
+#define D_CAN_IF_MCTL_INTPND	BIT(13)	/* Interrupt pending */
+#define D_CAN_IF_MCTL_UMASK	BIT(12)	/* Use acceptance mask */
+#define D_CAN_IF_MCTL_TXIE	BIT(11)	/* Transmit int enable */
+#define D_CAN_IF_MCTL_RXIE	BIT(10)	/* Receive int enable */
+#define D_CAN_IF_MCTL_RMTEN	BIT(9)	/* Remote enable */
+#define D_CAN_IF_MCTL_TXRQST	BIT(8)	/* Transmit request */
+#define D_CAN_IF_MCTL_EOB	BIT(7)	/* Data frames */
+#define D_CAN_IF_MCTL_DLC_MASK	0xF	/* Data length code */
+
+/* D_CAN IF3 Observation reg bit fields */
+#define D_CAN_IF3OBS_UP		BIT(15)	/* Update data status */
+#define D_CAN_IF3OBS_SDB	BIT(12)	/* DataB read out status */
+#define D_CAN_IF3OBS_SDA	BIT(11)	/* DataA read out status */
+#define D_CAN_IF3OBS_SC		BIT(10)	/* Contol bits read out status */
+#define D_CAN_IF3OBS_SA		BIT(9)	/* Arbitration read out status */
+#define D_CAN_IF3OBS_SM		BIT(8)	/* Mask bits read out status */
+#define D_CAN_IF3OBS_DB		BIT(4)	/* Data B read observation */
+#define D_CAN_IF3OBS_DA		BIT(3)	/* Data A read observation */
+#define D_CAN_IF3OBS_CTL	BIT(2)	/* Control read observation */
+#define D_CAN_IF3OBS_ARB	BIT(1)	/* Arbitration data read observation */
+#define D_CAN_IF3OBS_MASK	BIT(0)	/* Mask data read observation */
+
+/* D_CAN TX I/O reg bit fields */
+#define D_CAN_TIOC_PU		BIT(18)	/* CAN_TX pull up/down select */
+#define D_CAN_TIOC_PD		BIT(17)	/* CAN_TX pull disable */
+#define D_CAN_TIOC_OD		BIT(16)	/* CAN_TX open drain enable */
+#define D_CAN_TIOC_FUNC		BIT(3)	/* CAN_TX function */
+#define D_CAN_TIOC_DIR		BIT(2)	/* CAN_TX data direction */
+#define D_CAN_TIOC_OUT		BIT(1)	/* CAN_TX data out write */
+#define D_CAN_TIOC_IN		BIT(0)	/* CAN_TX data in */
+
+/* D_CAN RX I/O reg bit fields */
+#define D_CAN_RIOC_PU		BIT(18)	/* CAN_RX pull up/down select */
+#define D_CAN_RIOC_PD		BIT(17)	/* CAN_RX pull disable */
+#define D_CAN_RIOC_OD		BIT(16)	/* CAN_RX open drain enable */
+#define D_CAN_RIOC_FUNC		BIT(3)	/* CAN_RX function */
+#define D_CAN_RIOC_DIR		BIT(2)	/* CAN_RX data direction */
+#define D_CAN_RIOC_OUT		BIT(1)	/* CAN_RX data out write */
+#define D_CAN_RIOC_IN		BIT(0)	/* CAN_RX data in */
+
+/* IF register masks */
+#define IFX_WRITE_IDR(x)		((x) & 0x1FFFFFFF)
+#define IFX_CMD_BITS(x)			((x) & 0xFFFFFF00)
+#define IFX_CMD_MSG_NUMBER(x)		((x) & 0xFF)
+
+/* Message objects split */
+#define D_CAN_NUM_MSG_OBJECTS		64
+#define D_CAN_NUM_RX_MSG_OBJECTS	32
+#define D_CAN_NUM_TX_MSG_OBJECTS	32
+
+#define D_CAN_MSG_OBJ_RX_FIRST		1
+#define D_CAN_MSG_OBJ_RX_LAST		(D_CAN_MSG_OBJ_RX_FIRST + \
+					D_CAN_NUM_RX_MSG_OBJECTS - 1)
+
+#define D_CAN_MSG_OBJ_TX_FIRST		(D_CAN_MSG_OBJ_RX_LAST + 1)
+#define D_CAN_MSG_OBJ_TX_LAST		(D_CAN_MSG_OBJ_TX_FIRST + \
+					D_CAN_NUM_TX_MSG_OBJECTS - 1)
+
+#define D_CAN_MSG_OBJ_RX_SPLIT		17
+#define D_CAN_MSG_OBJ_RX_LOW_LAST	(D_CAN_MSG_OBJ_RX_SPLIT - 1)
+
+#define D_CAN_NEXT_MSG_OBJ_MASK		(D_CAN_NUM_TX_MSG_OBJECTS - 1)
+
+/* global interrupt masks */
+#define D_CAN_ENABLE_ALL_INTERRUPTS	1
+#define D_CAN_DISABLE_ALL_INTERRUPTS	0
+
+/* status interrupt */
+#define D_CAN_STATUS_INTERRUPT		0x8000
+
+#define D_CAN_BUSY_TIMEOUT		14
+#define D_CAN_TIMEOUT_MS		1000
+
+/* Interface register bank number */
+#define D_CAN_IF_RX_NUM			0
+#define D_CAN_IF_TX_NUM			1
+
+#define D_CAN_GET_XREG_NUM(priv, reg)	(__ffs(d_can_read(priv, reg)) >> 2)
+
+/* d_can private data structure */
+struct d_can_priv {
+	struct can_priv can;	/* must be the first member */
+	struct napi_struct napi;
+	struct net_device *dev;
+	struct platform_device *pdev;
+	unsigned int tx_next;
+	unsigned int tx_echo;
+	u32 current_status;
+	u32 last_status;
+	u32 irqstatus;
+	bool is_opened;
+	void __iomem *base;
+	void (*ram_init) (unsigned int, unsigned int);
+};
+
+/* CAN Bittiming constants as per D_CAN specs */
+static struct can_bittiming_const d_can_bittiming_const = {
+	.name		= D_CAN_DRV_NAME,
+	.tseg1_min	= 1,	/* Time segment 1 = prop_seg + phase_seg1 */
+	.tseg1_max	= 16,
+	.tseg2_min	= 1,	/* Time segment 2 = phase_seg2 */
+	.tseg2_max	= 8,
+	.sjw_max	= 4,
+	.brp_min	= 1,
+	.brp_max	= 1024,	/* 6-bit BRP field + 4-bit BRPE field*/
+	.brp_inc	= 1,
+};
+
+/* d_can last error code (lec) values */
+enum d_can_lec_type {
+	LEC_NO_ERROR = 0,
+	LEC_STUFF_ERROR,
+	LEC_FORM_ERROR,
+	LEC_ACK_ERROR,
+	LEC_BIT1_ERROR,
+	LEC_BIT0_ERROR,
+	LEC_CRC_ERROR,
+	LEC_UNUSED,
+};
+
+/* d_can error types */
+enum d_can_bus_error_types {
+	NO_ERROR = 0,
+	BUS_OFF,
+	ERROR_WARNING,
+	ERROR_PASSIVE,
+};
+
+static inline void d_can_write(struct d_can_priv *priv, u32 reg, u32 val)
+{
+	writel(val, priv->base + reg);
+}
+
+static inline u32 d_can_read(struct d_can_priv *priv, u32 reg)
+{
+	return readl(priv->base + reg);
+}
+
+static inline void d_can_set_bit(struct d_can_priv *priv, u32 reg, u32 bitmask)
+{
+	d_can_write(priv, reg, d_can_read(priv, reg) | bitmask);
+}
+
+static inline u32 d_can_get_bit(struct d_can_priv *priv, u32 reg, u32 bitmask)
+{
+	return (d_can_read(priv, reg) & bitmask) ? 1 : 0;
+}
+
+static inline void d_can_clear_bit(struct d_can_priv *priv, u32 reg,
+							u32 bitmask)
+{
+	d_can_write(priv, reg, d_can_read(priv, reg) & ~bitmask);
+}
+
+static inline int get_tx_next_msg_obj(const struct d_can_priv *priv)
+{
+	return (priv->tx_next & D_CAN_NEXT_MSG_OBJ_MASK) +
+			D_CAN_MSG_OBJ_TX_FIRST;
+}
+
+static inline int get_tx_echo_msg_obj(const struct d_can_priv *priv)
+{
+	return (priv->tx_echo & D_CAN_NEXT_MSG_OBJ_MASK) +
+			D_CAN_MSG_OBJ_TX_FIRST;
+}
+
+static void d_can_interrupts(struct d_can_priv *priv, unsigned int enable)
+{
+	unsigned int cntrl_save = d_can_read(priv, D_CAN_CTL);
+
+	if (enable)
+		cntrl_save |= (D_CAN_CTL_IE1 | D_CAN_CTL_EIE |
+				D_CAN_CTL_SIE | D_CAN_CTL_IE0);
+	else
+		cntrl_save &= ~(D_CAN_CTL_IE1 | D_CAN_CTL_EIE |
+				D_CAN_CTL_SIE | D_CAN_CTL_IE0);
+
+	d_can_write(priv, D_CAN_CTL, cntrl_save);
+}
+
+static inline int d_can_msg_obj_is_busy(struct d_can_priv *priv, u32 iface)
+{
+	unsigned long time_out = jiffies + msecs_to_jiffies(D_CAN_BUSY_TIMEOUT);
+
+	/* Check the status of busy bit */
+	while (d_can_get_bit(priv, D_CAN_IFCMD(iface), D_CAN_IF_CMD_BUSY) &&
+					time_after(time_out, jiffies))
+		cpu_relax();
+
+	if (time_after(jiffies, time_out))
+		return -ETIMEDOUT;
+
+	return 0;
+}
+
+static inline void d_can_object_get(struct net_device *dev,
+				u32 iface, u32 objno, u32 mask)
+{
+	struct d_can_priv *priv = netdev_priv(dev);
+
+	d_can_write(priv, D_CAN_IFCMD(iface), IFX_CMD_BITS(mask) |
+					IFX_CMD_MSG_NUMBER(objno));
+
+	/*
+	 * As per specs, after writing the message object number in the
+	 * IF command register the transfer b/w interface register and
+	 * message RAM must be complete in 4 - 14 CAN-CLK period.
+	 */
+	if (d_can_msg_obj_is_busy(priv, iface))
+		netdev_err(dev, "timed out in object get\n");
+}
+
+static inline void d_can_object_put(struct net_device *dev,
+				u32 iface, u32 objno, u32 mask)
+{
+	struct d_can_priv *priv = netdev_priv(dev);
+
+	d_can_write(priv, D_CAN_IFCMD(iface), D_CAN_IF_CMD_WR |
+		IFX_CMD_BITS(mask) | IFX_CMD_MSG_NUMBER(objno));
+
+	/*
+	 * As per specs, after writing the message object number in the
+	 * IF command register the transfer b/w interface register and
+	 * message RAM must be complete in 4 - 14 CAN-CLK period.
+	 */
+	if (d_can_msg_obj_is_busy(priv, iface))
+		netdev_err(dev, "timed out in object put\n");
+}
+
+static void d_can_write_msg_object(struct net_device *dev, u32 iface,
+				struct can_frame *frame, u32 objno)
+{
+	struct d_can_priv *priv = netdev_priv(dev);
+	unsigned int id;
+	u32 flags = 0;
+
+	if (!(frame->can_id & CAN_RTR_FLAG))
+		flags |= D_CAN_IF_ARB_DIR_XMIT;
+
+	if (frame->can_id & CAN_EFF_FLAG) {
+		id = frame->can_id & CAN_EFF_MASK;
+		flags |= D_CAN_IF_ARB_MSGXTD;
+	} else
+		id = ((frame->can_id & CAN_SFF_MASK) << 18);
+
+	flags |= D_CAN_IF_ARB_MSGVAL;
+	d_can_write(priv, D_CAN_IFARB(iface), IFX_WRITE_IDR(id) | flags);
+
+	/* Writing lower 4bytes to DATAA IF register */
+	d_can_write(priv, D_CAN_IFDATA(iface),
+				le32_to_cpu(*(u32 *)(frame->data)));
+
+	/* Writing higher 4bytes to DATAB IF register */
+	if (frame->can_dlc > 4)
+		d_can_write(priv, D_CAN_IFDATB(iface),
+				le32_to_cpu(*(u32 *)(frame->data + 4)));
+
+	/* enable TX interrupt for this message object */
+	d_can_write(priv, D_CAN_IFMCTL(iface),
+			D_CAN_IF_MCTL_TXIE | D_CAN_IF_MCTL_EOB |
+			D_CAN_IF_MCTL_TXRQST | D_CAN_IF_MCTL_NEWDAT |
+			frame->can_dlc);
+
+	/* Put message data into message RAM */
+	d_can_object_put(dev, iface, objno, D_CAN_IF_CMD_ALL);
+}
+
+/*
+ * Mark that this particular message object is received and clearing
+ * the interrupt pending register value.
+ */
+static inline void d_can_mark_rx_msg_obj(struct net_device *dev,
+			u32 iface, u32 ctrl_mask, u32 objno)
+{
+	struct d_can_priv *priv = netdev_priv(dev);
+
+	d_can_write(priv, D_CAN_IFMCTL(iface), ctrl_mask &
+			~(D_CAN_IF_MCTL_MSGLST | D_CAN_IF_MCTL_INTPND));
+	d_can_object_put(dev, iface, objno, D_CAN_IF_CMD_CONTROL);
+}
+
+static inline void d_can_activate_all_lower_rx_msg_objs(struct net_device *dev,
+						u32 iface, u32 ctrl_mask)
+{
+	unsigned int i;
+	struct d_can_priv *priv = netdev_priv(dev);
+
+	for (i = D_CAN_MSG_OBJ_RX_FIRST; i <= D_CAN_MSG_OBJ_RX_LOW_LAST; i++) {
+		d_can_write(priv, D_CAN_IFMCTL(iface), ctrl_mask &
+				~(D_CAN_IF_MCTL_MSGLST | D_CAN_IF_MCTL_INTPND |
+				D_CAN_IF_MCTL_NEWDAT));
+		d_can_object_put(dev, iface, i, D_CAN_IF_CMD_CONTROL);
+	}
+}
+
+static inline void d_can_activate_rx_msg_obj(struct net_device *dev,
+				u32 iface, u32 ctrl_mask, u32 objno)
+{
+	struct d_can_priv *priv = netdev_priv(dev);
+
+	d_can_write(priv, D_CAN_IFMCTL(iface), ctrl_mask &
+			~(D_CAN_IF_MCTL_MSGLST | D_CAN_IF_MCTL_INTPND |
+			D_CAN_IF_MCTL_NEWDAT));
+	d_can_object_put(dev, iface, objno, D_CAN_IF_CMD_CONTROL);
+}
+
+static void d_can_handle_lost_msg_obj(struct net_device *dev,
+					u32 iface, u32 objno)
+{
+	struct d_can_priv *priv = netdev_priv(dev);
+	struct net_device_stats *stats = &dev->stats;
+	struct sk_buff *skb;
+	struct can_frame *frame;
+
+	netdev_err(dev, "msg lost in buffer %d\n", objno);
+	d_can_object_get(dev, iface, objno, D_CAN_IF_CMD_ALL &
+					~D_CAN_IF_CMD_TXRQST);
+	d_can_clear_bit(priv, D_CAN_IFMCTL(iface), D_CAN_IF_MCTL_MSGLST);
+	d_can_object_put(dev, iface, objno, D_CAN_IF_CMD_CONTROL);
+
+	/* create an error msg */
+	skb = alloc_can_err_skb(dev, &frame);
+	if (unlikely(!skb))
+		return;
+
+	frame->can_id |= CAN_ERR_CRTL;
+	frame->data[1] = CAN_ERR_CRTL_RX_OVERFLOW;
+	stats->rx_errors++;
+	stats->rx_over_errors++;
+
+	netif_receive_skb(skb);
+}
+
+static int d_can_read_msg_object(struct net_device *dev, u32 iface, u32 ctrl)
+{
+	unsigned int arb_val, mctl_val;
+	struct d_can_priv *priv = netdev_priv(dev);
+	struct net_device_stats *stats = &dev->stats;
+	struct can_frame *frame;
+	struct sk_buff *skb;
+	u32 data = 0;
+
+	skb = alloc_can_skb(dev, &frame);
+	if (!skb) {
+		stats->rx_dropped++;
+		return -ENOMEM;
+	}
+
+	frame->can_dlc = get_can_dlc(ctrl & 0x0F);
+	arb_val = d_can_read(priv, D_CAN_IFARB(iface));
+	mctl_val = d_can_read(priv, D_CAN_IFMCTL(iface));
+
+	if (arb_val & D_CAN_IF_ARB_MSGXTD)
+		frame->can_id = (arb_val & CAN_EFF_MASK) | CAN_EFF_FLAG;
+	else
+		frame->can_id = (arb_val >> 18) & CAN_SFF_MASK;
+
+	if (mctl_val & D_CAN_IF_MCTL_RMTEN)
+		frame->can_id |= CAN_RTR_FLAG;
+	else {
+		data = d_can_read(priv, D_CAN_IFDATA(iface));
+		/* Writing MO lower 4 data bytes to skb */
+		*(u32 *)(frame->data) = cpu_to_le32(data);
+
+		/* Writing MO higher 4 data bytes to skb */
+		if (frame->can_dlc > 4) {
+			data = d_can_read(priv, D_CAN_IFDATB(iface));
+			*(u32 *)(frame->data + 4) = cpu_to_le32(data);
+		} else
+			*(u32 *)(frame->data + 4) = 0;
+	}
+
+	netif_receive_skb(skb);
+	stats->rx_packets++;
+	stats->rx_bytes += frame->can_dlc;
+
+	return 0;
+}
+
+static void d_can_setup_receive_object(struct net_device *dev, u32 iface,
+				u32 objno, u32 mask, u32 id, u32 mcont)
+{
+	struct d_can_priv *priv = netdev_priv(dev);
+
+	d_can_write(priv, D_CAN_IFMCTL(iface), mcont);
+	d_can_write(priv, D_CAN_IFMSK(iface), IFX_WRITE_IDR(mask));
+	d_can_write(priv, D_CAN_IFARB(iface), IFX_WRITE_IDR(id) |
+						D_CAN_IF_ARB_MSGVAL);
+	d_can_object_put(dev, iface, objno, D_CAN_IF_CMD_ALL &
+					~D_CAN_IF_CMD_TXRQST);
+
+	netdev_dbg(dev, "obj no:%d, msgval:0x%08x\n", objno, d_can_read(priv,
+		D_CAN_MSGVAL(D_CAN_GET_XREG_NUM(priv, D_CAN_MSGVAL_X))));
+}
+
+static void d_can_inval_msg_object(struct net_device *dev, u32 iface, u32 objno)
+{
+	struct d_can_priv *priv = netdev_priv(dev);
+
+	d_can_write(priv, D_CAN_IFARB(iface), 0);
+	d_can_write(priv, D_CAN_IFMCTL(iface), 0);
+	d_can_object_put(dev, iface, objno, D_CAN_IF_CMD_ARB |
+					D_CAN_IF_CMD_CONTROL);
+
+	netdev_dbg(dev, "obj no:%d, msgval:0x%08x\n", objno, d_can_read(priv,
+		D_CAN_MSGVAL(D_CAN_GET_XREG_NUM(priv, D_CAN_MSGVAL_X))));
+}
+
+static inline int d_can_is_next_tx_obj_busy(struct d_can_priv *priv, u32 objno)
+{
+	u32 txrq_x_reg_val = D_CAN_GET_XREG_NUM(priv, D_CAN_TXRQ_X);
+
+	/* Transmission request register's bit n-1 corresponds to
+	 * message object n, we need to handle the same properly */
+	if (d_can_read(priv, D_CAN_TXRQ(txrq_x_reg_val)) &
+			(1 << (objno - D_CAN_MSG_OBJ_TX_FIRST)))
+		return 1;
+
+	return 0;
+}
+
+static netdev_tx_t d_can_start_xmit(struct sk_buff *skb, struct net_device *dev)
+{
+	u32 msg_obj_no;
+	struct d_can_priv *priv = netdev_priv(dev);
+	struct can_frame *frame = (struct can_frame *)skb->data;
+
+	if (can_dropped_invalid_skb(dev, skb))
+		return NETDEV_TX_OK;
+
+	msg_obj_no = get_tx_next_msg_obj(priv);
+
+	/* prepare message object for transmission */
+	d_can_write_msg_object(dev, D_CAN_IF_TX_NUM, frame, msg_obj_no);
+	can_put_echo_skb(skb, dev, msg_obj_no - D_CAN_MSG_OBJ_TX_FIRST);
+
+	/*
+	 * we have to stop the queue in case of a wrap around or
+	 * if the next TX message object is still in use
+	 */
+	priv->tx_next++;
+	if (d_can_is_next_tx_obj_busy(priv, get_tx_next_msg_obj(priv)) ||
+		((priv->tx_next & D_CAN_NEXT_MSG_OBJ_MASK) == 0))
+		netif_stop_queue(dev);
+
+	return NETDEV_TX_OK;
+}
+
+static void d_can_set_bittiming(struct net_device *dev)
+{
+	struct d_can_priv *priv = netdev_priv(dev);
+	const struct can_bittiming *bt = &priv->can.bittiming;
+	u32 can_btc;
+
+	can_btc = ((bt->phase_seg2 - 1) & 0x7) << D_CAN_BTR_TSEG2_SHIFT;
+	can_btc |= ((bt->phase_seg1 + bt->prop_seg - 1) & 0xF) <<
+						D_CAN_BTR_TSEG1_SHIFT;
+	can_btc |= ((bt->sjw - 1) & 0x3) << D_CAN_BTR_SJW_SHIFT;
+	/* Ten bits contains the BRP, 6 bits for BRP and upper 4 bits for brpe*/
+	can_btc |= ((bt->brp - 1) & 0x3F) << D_CAN_BTR_BRP_SHIFT;
+	can_btc |= ((((bt->brp - 1) >> 6) & 0xF) << D_CAN_BTR_BRPE_SHIFT);
+
+	d_can_write(priv, D_CAN_BTR, can_btc);
+	netdev_info(dev, "setting CAN BT = %#x\n", can_btc);
+}
+
+/*
+ * Configure D_CAN message objects for Tx and Rx purposes:
+ * D_CAN provides a total of 64 message objects that can be configured
+ * either for Tx or Rx purposes. In this driver first 32 message objects
+ * are used as a reception FIFO and the reception FIFO is signified by the
+ * EoB bit being SET. The remaining 32 message objects are kept aside for
+ * Tx purposes. See user guide document for further details on configuring
+ * message objects.
+ */
+static void d_can_configure_msg_objects(struct net_device *dev)
+{
+	unsigned int i;
+
+	/* first invalidate all message objects */
+	for (i = D_CAN_MSG_OBJ_RX_FIRST; i <= D_CAN_NUM_MSG_OBJECTS; i++)
+		d_can_inval_msg_object(dev, D_CAN_IF_RX_NUM, i);
+
+	/* setup receive message objects */
+	for (i = D_CAN_MSG_OBJ_RX_FIRST; i < D_CAN_MSG_OBJ_RX_LAST; i++)
+		d_can_setup_receive_object(dev, D_CAN_IF_RX_NUM, i, 0, 0,
+			(D_CAN_IF_MCTL_RXIE | D_CAN_IF_MCTL_UMASK) &
+			~D_CAN_IF_MCTL_EOB);
+
+	/* Last object EoB bit should be 1 for terminate */
+	d_can_setup_receive_object(dev, D_CAN_IF_RX_NUM, D_CAN_MSG_OBJ_RX_LAST,
+			0, 0, D_CAN_IF_MCTL_RXIE | D_CAN_IF_MCTL_UMASK |
+			D_CAN_IF_MCTL_EOB);
+}
+
+static void d_can_test_mode(struct net_device *dev)
+{
+	struct d_can_priv *priv = netdev_priv(dev);
+
+	/* Test mode is enabled in this step & the specific TEST bits
+	 * are enabled accordingly */
+	d_can_write(priv, D_CAN_CTL, D_CAN_CTL_EIE |
+			D_CAN_CTL_IE1 |	D_CAN_CTL_IE0 | D_CAN_CTL_TEST);
+
+	if (priv->can.ctrlmode & CAN_CTRLMODE_LISTENONLY)
+		/* silent mode : bus-monitoring mode */
+		d_can_write(priv, D_CAN_TEST, D_CAN_TEST_SILENT);
+	else if (priv->can.ctrlmode & CAN_CTRLMODE_LOOPBACK)
+		/* loopback mode : useful for self-test function */
+		d_can_write(priv, D_CAN_TEST, D_CAN_TEST_LBACK);
+	else
+		/* loopback + silent mode : useful for hot self-test */
+		d_can_write(priv, D_CAN_TEST, D_CAN_TEST_LBACK |
+				D_CAN_TEST_SILENT);
+}
+
+/*
+ * Configure D_CAN chip:
+ * - enable/disable auto-retransmission
+ * - set operating mode
+ * - configure message objects
+ */
+static void d_can_init(struct net_device *dev)
+{
+	struct d_can_priv *priv = netdev_priv(dev);
+	unsigned long time_out;
+
+	netdev_dbg(dev, "resetting d_can ...\n");
+	d_can_set_bit(priv, D_CAN_CTL, D_CAN_CTL_SWR);
+
+	/* Enter initialization mode by setting the Init bit */
+	d_can_set_bit(priv, D_CAN_CTL, D_CAN_CTL_INIT);
+
+	/* enable automatic retransmission */
+	d_can_clear_bit(priv, D_CAN_CTL, D_CAN_CTL_DISABLE_AR);
+
+	/* Set the Configure Change Enable ( CCE) bit */
+	d_can_set_bit(priv, D_CAN_CTL, D_CAN_CTL_CCE);
+
+	/* Wait for the Init bit to get set */
+	time_out = jiffies + msecs_to_jiffies(D_CAN_TIMEOUT_MS);
+	while (!d_can_get_bit(priv, D_CAN_CTL, D_CAN_CTL_INIT) &&
+					time_after(time_out, jiffies))
+		cpu_relax();
+
+	if (time_after(jiffies, time_out)) {
+		netdev_err(dev, "timedout, D_CAN INIT bit is not set\n");
+		return;
+	}
+
+	/* set bittiming params */
+	d_can_set_bittiming(dev);
+
+	d_can_clear_bit(priv, D_CAN_CTL, D_CAN_CTL_INIT | D_CAN_CTL_CCE);
+
+	/* Wait for the Init bit to get clear */
+	time_out = jiffies + msecs_to_jiffies(D_CAN_TIMEOUT_MS);
+	while (d_can_get_bit(priv, D_CAN_CTL, D_CAN_CTL_INIT) &&
+					time_after(time_out, jiffies))
+		cpu_relax();
+
+	if (time_after(jiffies, time_out)) {
+		netdev_err(dev, "timedout, D_CAN INIT bit is not cleared\n");
+		return;
+	}
+
+	if (priv->can.ctrlmode & (CAN_CTRLMODE_LOOPBACK |
+				CAN_CTRLMODE_LISTENONLY))
+		d_can_test_mode(dev);
+	else
+		d_can_write(priv, D_CAN_CTL, D_CAN_CTL_EIE | D_CAN_CTL_IE1 |
+					D_CAN_CTL_SIE | D_CAN_CTL_IE0);
+
+	/* Enable TX and RX I/O Control pins */
+	d_can_write(priv, D_CAN_TIOC, D_CAN_TIOC_FUNC);
+	d_can_write(priv, D_CAN_RIOC, D_CAN_RIOC_FUNC);
+
+	/* configure message objects */
+	d_can_configure_msg_objects(dev);
+
+	/* set a LEC value so that we can check for updates later */
+	d_can_write(priv, D_CAN_ES, LEC_UNUSED);
+}
+
+static void d_can_start(struct net_device *dev)
+{
+	struct d_can_priv *priv = netdev_priv(dev);
+
+	/* basic d_can initialization */
+	d_can_init(dev);
+
+	priv->can.state = CAN_STATE_ERROR_ACTIVE;
+
+	/* reset tx helper pointers */
+	priv->tx_next = priv->tx_echo = 0;
+
+	/* enable status change, error and module interrupts */
+	d_can_interrupts(priv, D_CAN_ENABLE_ALL_INTERRUPTS);
+}
+
+static void d_can_stop(struct net_device *dev)
+{
+	struct d_can_priv *priv = netdev_priv(dev);
+
+	d_can_interrupts(priv, D_CAN_DISABLE_ALL_INTERRUPTS);
+
+	/* set the state as STOPPED */
+	priv->can.state = CAN_STATE_STOPPED;
+}
+
+static int d_can_set_mode(struct net_device *dev, enum can_mode mode)
+{
+	switch (mode) {
+	case CAN_MODE_START:
+		d_can_start(dev);
+		netif_wake_queue(dev);
+		break;
+	default:
+		return -EOPNOTSUPP;
+	}
+
+	return 0;
+}
+
+static int d_can_get_berr_counter(const struct net_device *dev,
+					struct can_berr_counter *bec)
+{
+	unsigned int err_cnt;
+	struct d_can_priv *priv = netdev_priv(dev);
+
+	err_cnt = d_can_read(priv, D_CAN_ERRC);
+	bec->rxerr = (err_cnt & D_CAN_ERRC_REC_MASK) >> D_CAN_ERRC_REC_SHIFT;
+	bec->txerr = err_cnt & D_CAN_ERRC_TEC_MASK;
+
+	return 0;
+}
+
+/*
+ * priv->tx_echo holds the number of the oldest can_frame put for
+ * transmission into the hardware, but not yet ACKed by the CAN tx
+ * complete IRQ.
+ * We iterate from priv->tx_echo to priv->tx_next and check if the
+ * packet has been transmitted, echo it back to the CAN framework.
+ * If we discover a not yet transmitted packet, stop looking for more.
+ */
+static void d_can_do_tx(struct net_device *dev)
+{
+	u32 msg_obj_no;
+	struct d_can_priv *priv = netdev_priv(dev);
+	struct net_device_stats *stats = &dev->stats;
+	u32 txrq_x_reg_val;
+	u32 txrq_reg_val;
+
+	for (/* nix */; (priv->tx_next - priv->tx_echo) > 0; priv->tx_echo++) {
+		msg_obj_no = get_tx_echo_msg_obj(priv);
+		txrq_x_reg_val = D_CAN_GET_XREG_NUM(priv, D_CAN_TXRQ_X);
+		txrq_reg_val = d_can_read(priv, D_CAN_TXRQ(txrq_x_reg_val));
+		if (!(txrq_reg_val & (1 << (msg_obj_no -
+						D_CAN_MSG_OBJ_TX_FIRST)))) {
+			can_get_echo_skb(dev,
+					msg_obj_no - D_CAN_MSG_OBJ_TX_FIRST);
+			stats->tx_bytes += d_can_read(priv,
+					D_CAN_IFMCTL(D_CAN_IF_TX_NUM)) &
+					D_CAN_IF_MCTL_DLC_MASK;
+			stats->tx_packets++;
+			d_can_inval_msg_object(dev, D_CAN_IF_TX_NUM,
+					msg_obj_no);
+		} else
+			break;
+	}
+
+	/* restart queue if wrap-up or if queue stalled on last pkt */
+	if (((priv->tx_next & D_CAN_NEXT_MSG_OBJ_MASK) != 0) ||
+		((priv->tx_echo & D_CAN_NEXT_MSG_OBJ_MASK) == 0))
+		netif_wake_queue(dev);
+}
+
+/*
+ * d_can core saves a received CAN message into the first free message
+ * object it finds free (starting with the lowest). Bits NEWDAT and
+ * INTPND are set for this message object indicating that a new message
+ * has arrived. To work-around this issue, we keep two groups of message
+ * objects whose partitioning is defined by D_CAN_MSG_OBJ_RX_SPLIT.
+ *
+ * To ensure in-order frame reception we use the following
+ * approach while re-activating a message object to receive further
+ * frames:
+ * - if the current message object number is lower than
+ *   D_CAN_MSG_RX_LOW_LAST, do not clear the NEWDAT bit while clearing
+ *   the INTPND bit.
+ * - if the current message object number is equal to
+ *   D_CAN_MSG_RX_LOW_LAST then clear the NEWDAT bit of all lower
+ *   receive message objects.
+ * - if the current message object number is greater than
+ *   D_CAN_MSG_RX_LOW_LAST then clear the NEWDAT bit of
+ *   only this message object.
+ */
+static int d_can_do_rx_poll(struct net_device *dev, int quota)
+{
+	struct d_can_priv *priv = netdev_priv(dev);
+	unsigned int msg_obj, mctrl_reg_val;
+	u32 num_rx_pkts = 0;
+	u32 intpnd_x_reg_val;
+	u32 intpnd_reg_val;
+
+	for (msg_obj = D_CAN_MSG_OBJ_RX_FIRST;
+		msg_obj <= D_CAN_MSG_OBJ_RX_LAST && quota > 0; msg_obj++) {
+
+		intpnd_x_reg_val = D_CAN_GET_XREG_NUM(priv, D_CAN_INTPND_X);
+		intpnd_reg_val = d_can_read(priv,
+					D_CAN_INTPND(intpnd_x_reg_val));
+
+		/*
+		 * as interrupt pending register's bit n-1 corresponds to
+		 * message object n, we need to handle the same properly.
+		 */
+		if (intpnd_reg_val & (1 << (msg_obj - 1))) {
+
+			d_can_object_get(dev, D_CAN_IF_RX_NUM, msg_obj,
+					D_CAN_IF_CMD_ALL &
+					~D_CAN_IF_CMD_TXRQST);
+
+			mctrl_reg_val = d_can_read(priv,
+					D_CAN_IFMCTL(D_CAN_IF_RX_NUM));
+
+			if (!(mctrl_reg_val & D_CAN_IF_MCTL_NEWDAT))
+				continue;
+
+			/* read the data from the message object */
+			d_can_read_msg_object(dev, D_CAN_IF_RX_NUM,
+						mctrl_reg_val);
+
+			if (mctrl_reg_val & D_CAN_IF_MCTL_EOB)
+				d_can_setup_receive_object(dev, D_CAN_IF_RX_NUM,
+					D_CAN_MSG_OBJ_RX_LAST, 0, 0,
+					D_CAN_IF_MCTL_RXIE |
+					D_CAN_IF_MCTL_UMASK |
+					D_CAN_IF_MCTL_EOB);
+
+			if (mctrl_reg_val & D_CAN_IF_MCTL_MSGLST) {
+				d_can_handle_lost_msg_obj(dev, D_CAN_IF_RX_NUM,
+					msg_obj);
+				num_rx_pkts++;
+				quota--;
+				continue;
+			}
+
+			if (msg_obj < D_CAN_MSG_OBJ_RX_LOW_LAST)
+				d_can_mark_rx_msg_obj(dev, D_CAN_IF_RX_NUM,
+						mctrl_reg_val, msg_obj);
+			else if (msg_obj > D_CAN_MSG_OBJ_RX_LOW_LAST)
+				/* activate this msg obj */
+				d_can_activate_rx_msg_obj(dev, D_CAN_IF_RX_NUM,
+						mctrl_reg_val, msg_obj);
+			else if (msg_obj == D_CAN_MSG_OBJ_RX_LOW_LAST)
+				/* activate all lower message objects */
+				d_can_activate_all_lower_rx_msg_objs(dev,
+						D_CAN_IF_RX_NUM, mctrl_reg_val);
+
+			num_rx_pkts++;
+			quota--;
+		}
+	}
+	return num_rx_pkts;
+}
+
+static inline int d_can_has_handle_berr(struct d_can_priv *priv)
+{
+	return (priv->can.ctrlmode & CAN_CTRLMODE_BERR_REPORTING) &&
+		(priv->current_status & LEC_UNUSED);
+}
+
+static int d_can_handle_state_change(struct net_device *dev,
+				enum d_can_bus_error_types error_type)
+{
+	unsigned int err_cnt;
+	unsigned int rx_epass;
+	struct d_can_priv *priv = netdev_priv(dev);
+	struct net_device_stats *stats = &dev->stats;
+	struct can_frame *cf;
+	struct sk_buff *skb;
+	struct can_berr_counter bec;
+
+	/* propagate the error condition to the CAN stack */
+	skb = alloc_can_err_skb(dev, &cf);
+	if (unlikely(!skb))
+		return 0;
+
+	d_can_get_berr_counter(dev, &bec);
+	err_cnt = d_can_read(priv, D_CAN_ERRC);
+	rx_epass = err_cnt & D_CAN_ERRC_RP_MASK;
+
+	switch (error_type) {
+	case ERROR_WARNING:
+		/* error warning state */
+		priv->can.can_stats.error_warning++;
+		priv->can.state = CAN_STATE_ERROR_WARNING;
+		cf->can_id |= CAN_ERR_CRTL;
+		cf->data[1] = (bec.txerr > bec.rxerr) ?
+			CAN_ERR_CRTL_TX_WARNING :
+			CAN_ERR_CRTL_RX_WARNING;
+		cf->data[6] = bec.txerr;
+		cf->data[7] = bec.rxerr;
+
+		break;
+	case ERROR_PASSIVE:
+		/* error passive state */
+		priv->can.can_stats.error_passive++;
+		priv->can.state = CAN_STATE_ERROR_PASSIVE;
+		cf->can_id |= CAN_ERR_CRTL;
+		if (rx_epass)
+			cf->data[1] |= CAN_ERR_CRTL_RX_PASSIVE;
+		if (bec.txerr > 127)
+			cf->data[1] |= CAN_ERR_CRTL_TX_PASSIVE;
+
+		cf->data[6] = bec.txerr;
+		cf->data[7] = bec.rxerr;
+		break;
+	case BUS_OFF:
+		/* bus-off state */
+		priv->can.state = CAN_STATE_BUS_OFF;
+		cf->can_id |= CAN_ERR_BUSOFF;
+		/*
+		 * disable all interrupts in bus-off mode to ensure that
+		 * the CPU is not hogged down
+		 */
+		d_can_interrupts(priv, D_CAN_DISABLE_ALL_INTERRUPTS);
+		can_bus_off(dev);
+		break;
+	default:
+		break;
+	}
+	netif_receive_skb(skb);
+	stats->rx_packets++;
+	stats->rx_bytes += cf->can_dlc;
+
+	return 1;
+}
+
+static int d_can_handle_bus_err(struct net_device *dev,
+				enum d_can_lec_type lec_type)
+{
+	struct d_can_priv *priv = netdev_priv(dev);
+	struct net_device_stats *stats = &dev->stats;
+	struct can_frame *cf;
+	struct sk_buff *skb;
+
+	/*
+	 * early exit if no lec update or no error.
+	 * no lec update means that no CAN bus event has been detected
+	 * since CPU wrote 0x7 value to status reg.
+	 */
+	if (lec_type == LEC_UNUSED || lec_type == LEC_NO_ERROR)
+		return 0;
+
+	/* propagate the error condition to the CAN stack */
+	skb = alloc_can_err_skb(dev, &cf);
+	if (unlikely(!skb))
+		return 0;
+
+	/* common for all type of bus errors */
+	priv->can.can_stats.bus_error++;
+	stats->rx_errors++;
+	cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;
+	cf->data[2] |= CAN_ERR_PROT_UNSPEC;
+
+	switch (lec_type) {
+	case LEC_STUFF_ERROR:
+		netdev_dbg(dev, "stuff error\n");
+		cf->data[2] |= CAN_ERR_PROT_STUFF;
+		break;
+	case LEC_FORM_ERROR:
+		netdev_dbg(dev, "form error\n");
+		cf->data[2] |= CAN_ERR_PROT_FORM;
+		break;
+	case LEC_ACK_ERROR:
+		netdev_dbg(dev, "ack error\n");
+		cf->data[2] |= (CAN_ERR_PROT_LOC_ACK |
+				CAN_ERR_PROT_LOC_ACK_DEL);
+		break;
+	case LEC_BIT1_ERROR:
+		netdev_dbg(dev, "bit1 error\n");
+		cf->data[2] |= CAN_ERR_PROT_BIT1;
+		break;
+	case LEC_BIT0_ERROR:
+		netdev_dbg(dev, "bit0 error\n");
+		cf->data[2] |= CAN_ERR_PROT_BIT0;
+		break;
+	case LEC_CRC_ERROR:
+		netdev_dbg(dev, "CRC error\n");
+		cf->data[2] |= (CAN_ERR_PROT_LOC_CRC_SEQ |
+				CAN_ERR_PROT_LOC_CRC_DEL);
+		break;
+	default:
+		break;
+	}
+
+	/* set a LEC value so that we can check for updates later */
+	d_can_write(priv, D_CAN_ES, LEC_UNUSED);
+
+	netif_receive_skb(skb);
+	stats->rx_packets++;
+	stats->rx_bytes += cf->can_dlc;
+
+	return 1;
+}
+
+static int d_can_poll(struct napi_struct *napi, int quota)
+{
+	int work_done = 0;
+	int lec_type = 0;
+	struct net_device *dev = napi->dev;
+	struct d_can_priv *priv = netdev_priv(dev);
+
+	if (!priv->irqstatus)
+		goto end;
+
+	/* status events have the highest priority */
+	if (priv->irqstatus == D_CAN_STATUS_INTERRUPT) {
+		priv->current_status = d_can_read(priv, D_CAN_ES);
+
+		/* handle Tx/Rx events */
+		if (priv->current_status & D_CAN_ES_TXOK)
+			d_can_write(priv, D_CAN_ES,
+					priv->current_status & ~D_CAN_ES_TXOK);
+
+		if (priv->current_status & D_CAN_ES_RXOK)
+			d_can_write(priv, D_CAN_ES,
+					priv->current_status & ~D_CAN_ES_RXOK);
+
+		/* handle state changes */
+		if ((priv->current_status & D_CAN_ES_EWARN) &&
+				(!(priv->last_status & D_CAN_ES_EWARN))) {
+			netdev_dbg(dev, "entered error warning state\n");
+			work_done += d_can_handle_state_change(dev,
+						ERROR_WARNING);
+		}
+		if ((priv->current_status & D_CAN_ES_EPASS) &&
+				(!(priv->last_status & D_CAN_ES_EPASS))) {
+			netdev_dbg(dev, "entered error passive state\n");
+			work_done += d_can_handle_state_change(dev,
+						ERROR_PASSIVE);
+		}
+		if ((priv->current_status & D_CAN_ES_BOFF) &&
+				(!(priv->last_status & D_CAN_ES_BOFF))) {
+			netdev_dbg(dev, "entered bus off state\n");
+			work_done += d_can_handle_state_change(dev, BUS_OFF);
+		}
+
+		/* handle bus recovery events */
+		if ((!(priv->current_status & D_CAN_ES_BOFF)) &&
+				(priv->last_status & D_CAN_ES_BOFF)) {
+			netdev_dbg(dev, "left bus off state\n");
+			priv->can.state = CAN_STATE_ERROR_ACTIVE;
+		}
+		if ((!(priv->current_status & D_CAN_ES_EPASS)) &&
+				(priv->last_status & D_CAN_ES_EPASS)) {
+			netdev_dbg(dev, "left error passive state\n");
+			priv->can.state = CAN_STATE_ERROR_ACTIVE;
+		}
+		priv->last_status = priv->current_status;
+
+		/* handle lec errors on the bus */
+		lec_type = d_can_has_handle_berr(priv);
+		if (lec_type)
+			work_done += d_can_handle_bus_err(dev, lec_type);
+	} else if ((priv->irqstatus >= D_CAN_MSG_OBJ_RX_FIRST) &&
+			(priv->irqstatus <= D_CAN_MSG_OBJ_RX_LAST)) {
+		/* handle events corresponding to receive message objects */
+		work_done += d_can_do_rx_poll(dev, (quota - work_done));
+	} else if ((priv->irqstatus >= D_CAN_MSG_OBJ_TX_FIRST) &&
+			(priv->irqstatus <= D_CAN_MSG_OBJ_TX_LAST)) {
+		/* handle events corresponding to transmit message objects */
+		d_can_do_tx(dev);
+	}
+end:
+	if (work_done < quota) {
+		napi_complete(napi);
+		d_can_interrupts(priv, D_CAN_ENABLE_ALL_INTERRUPTS);
+	}
+	return work_done;
+}
+
+static irqreturn_t d_can_isr(int irq, void *dev_id)
+{
+	struct net_device *dev = (struct net_device *)dev_id;
+	struct d_can_priv *priv = netdev_priv(dev);
+
+	priv->irqstatus = d_can_read(priv, D_CAN_INT);
+	if (!priv->irqstatus)
+		return IRQ_NONE;
+
+	/* disable all interrupts and schedule the NAPI */
+	d_can_interrupts(priv, D_CAN_DISABLE_ALL_INTERRUPTS);
+	napi_schedule(&priv->napi);
+
+	return IRQ_HANDLED;
+}
+
+static int d_can_open(struct net_device *ndev)
+{
+	int err;
+	struct d_can_priv *priv = netdev_priv(ndev);
+
+	/* Open common can device */
+	err = open_candev(ndev);
+	if (err) {
+		netdev_err(ndev, "open_candev() failed %d\n", err);
+		return err;
+	}
+
+	err = request_irq(ndev->irq, &d_can_isr, IRQF_SHARED, ndev->name,
+				ndev);
+	if (err) {
+		netdev_err(ndev, "failed to request MO_ES interrupt\n");
+		goto exit_close_candev;
+	}
+
+	/* start the d_can controller */
+	d_can_start(ndev);
+	napi_enable(&priv->napi);
+	netif_start_queue(ndev);
+	priv->is_opened = true;
+
+	return 0;
+exit_close_candev:
+	close_candev(ndev);
+	return err;
+}
+
+static int d_can_close(struct net_device *ndev)
+{
+	struct d_can_priv *priv = netdev_priv(ndev);
+
+	netif_stop_queue(ndev);
+	napi_disable(&priv->napi);
+	d_can_stop(ndev);
+	free_irq(ndev->irq, ndev);
+	close_candev(ndev);
+	priv->is_opened = false;
+
+	return 0;
+}
+
+static void d_can_reset_ram(struct d_can_priv *d_can, unsigned int instance,
+					unsigned int enable)
+{
+	if (d_can->ram_init)
+		d_can->ram_init(instance, enable);
+	/* Give some time delay for DCAN RAM initialization */
+	udelay(1);
+}
+
+static struct net_device *alloc_d_can_dev(unsigned int num_objs)
+{
+	struct net_device *dev;
+	struct d_can_priv *priv;
+
+	dev = alloc_candev(sizeof(struct d_can_priv), num_objs/2);
+	if (!dev)
+		return NULL;
+
+	priv = netdev_priv(dev);
+	netif_napi_add(dev, &priv->napi, d_can_poll, num_objs/2);
+
+	priv->dev = dev;
+	priv->can.bittiming_const = &d_can_bittiming_const;
+	priv->can.do_set_mode = d_can_set_mode;
+	priv->can.do_get_berr_counter = d_can_get_berr_counter;
+	priv->can.ctrlmode_supported = (CAN_CTRLMODE_LOOPBACK |
+					CAN_CTRLMODE_LISTENONLY |
+					CAN_CTRLMODE_BERR_REPORTING |
+					CAN_CTRLMODE_3_SAMPLES);
+	return dev;
+}
+
+static void free_d_can_dev(struct net_device *dev)
+{
+	free_candev(dev);
+}
+
+static const struct net_device_ops d_can_netdev_ops = {
+	.ndo_open	= d_can_open,
+	.ndo_stop	= d_can_close,
+	.ndo_start_xmit	= d_can_start_xmit,
+};
+
+static int register_d_can_dev(struct net_device *dev)
+{
+	/* we support local echo */
+	dev->flags |= IFF_ECHO;
+	dev->netdev_ops = &d_can_netdev_ops;
+	return register_candev(dev);
+}
+
+static void unregister_d_can_dev(struct net_device *dev)
+{
+	struct d_can_priv *priv = netdev_priv(dev);
+
+	d_can_interrupts(priv, D_CAN_DISABLE_ALL_INTERRUPTS);
+	unregister_candev(dev);
+}
+
+static int __devinit d_can_plat_probe(struct platform_device *pdev)
+{
+	int ret = 0;
+	void __iomem *addr;
+	struct net_device *ndev;
+	struct d_can_priv *priv;
+	struct resource *mem, *irq;
+	struct d_can_platform_data *pdata;
+	struct clk *fck;
+
+	pdata = pdev->dev.platform_data;
+	if (!pdata) {
+		dev_err(&pdev->dev, "No platform data\n");
+		goto exit;
+	}
+
+	/* get the platform data */
+	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!mem) {
+		ret = -ENODEV;
+		dev_err(&pdev->dev, "No mem resource\n");
+		goto exit;
+	}
+	irq = platform_get_resource_byname(pdev, IORESOURCE_IRQ, "d_can_ms");
+	if (!irq) {
+		dev_err(&pdev->dev, "No irq resource\n");
+		goto exit;
+	}
+	if (!request_mem_region(mem->start, resource_size(mem),
+				D_CAN_DRV_NAME)) {
+		dev_err(&pdev->dev, "resource unavailable\n");
+		ret = -EBUSY;
+		goto exit;
+	}
+	addr = ioremap(mem->start, resource_size(mem));
+	if (!addr) {
+		dev_err(&pdev->dev, "ioremap failed\n");
+		ret = -ENOMEM;
+		goto exit_release_mem;
+	}
+
+	/* allocate the d_can device */
+	ndev = alloc_d_can_dev(pdata->num_of_msg_objs);
+	if (!ndev) {
+		dev_err(&pdev->dev, "alloc_d_can_dev failed\n");
+		ret = -ENOMEM;
+		goto exit_iounmap;
+	}
+	fck = clk_get(&pdev->dev, "fck");
+	if (IS_ERR(fck)) {
+		dev_err(&pdev->dev, "fck is not found\n");
+		ret = -ENODEV;
+		goto exit_free_ndev;
+	}
+
+	priv = netdev_priv(ndev);
+	priv->base = addr;
+	priv->can.clock.freq = clk_get_rate(fck);
+	priv->ram_init = pdata->ram_init;
+	priv->is_opened = false;
+
+	ndev->irq = irq->start;
+	platform_set_drvdata(pdev, ndev);
+	SET_NETDEV_DEV(ndev, &pdev->dev);
+
+	pm_runtime_enable(&pdev->dev);
+	pm_runtime_get_sync(&pdev->dev);
+
+	ret = register_d_can_dev(ndev);
+	if (ret) {
+		dev_err(&pdev->dev, "registering %s failed (err = %d)\n",
+				D_CAN_DRV_NAME, ret);
+		goto exit_free_device;
+	}
+
+	/* Initialize DCAN RAM */
+	d_can_reset_ram(priv, pdev->id, 1);
+
+	dev_info(&pdev->dev, "device registered (irq = %d)\n", ndev->irq);
+	return 0;
+exit_free_device:
+	platform_set_drvdata(pdev, NULL);
+	pm_runtime_disable(&pdev->dev);
+	clk_put(fck);
+exit_free_ndev:
+	free_d_can_dev(ndev);
+exit_iounmap:
+	iounmap(addr);
+exit_release_mem:
+	release_mem_region(mem->start, resource_size(mem));
+exit:
+	dev_err(&pdev->dev, "probe failed\n");
+	return ret;
+}
+
+static int __devexit d_can_plat_remove(struct platform_device *pdev)
+{
+	struct net_device *ndev = platform_get_drvdata(pdev);
+	struct d_can_priv *priv = netdev_priv(ndev);
+	struct resource *mem;
+
+	d_can_reset_ram(priv, pdev->id, 0);
+
+	unregister_d_can_dev(ndev);
+	platform_set_drvdata(pdev, NULL);
+
+	free_d_can_dev(ndev);
+	iounmap(priv->base);
+
+	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	release_mem_region(mem->start, resource_size(mem));
+
+	pm_runtime_put_sync(&pdev->dev);
+	pm_runtime_disable(&pdev->dev);
+
+	return 0;
+}
+
+#ifdef CONFIG_PM
+static int d_can_suspend(struct platform_device *pdev, pm_message_t state)
+{
+	unsigned long time_out;
+	struct net_device *ndev = platform_get_drvdata(pdev);
+	struct d_can_priv *priv = netdev_priv(ndev);
+
+	if (netif_running(ndev)) {
+		netif_stop_queue(ndev);
+		netif_device_detach(ndev);
+	}
+
+	d_can_set_bit(priv, D_CAN_CTL, D_CAN_CTL_PDR);
+
+	/* PDA bit will become high only when all the pending
+	 * transfers are completed */
+	time_out = jiffies + msecs_to_jiffies(D_CAN_TIMEOUT_MS);
+	while (!d_can_get_bit(priv, D_CAN_ES, D_CAN_ES_PDA) &&
+				time_after(time_out, jiffies))
+		cpu_relax();
+
+	if (time_after(jiffies, time_out)) {
+		netdev_err(ndev, "Not entered power down mode\n");
+		return -ETIMEDOUT;
+	}
+
+	if (priv->is_opened)
+		d_can_stop(ndev);
+
+	priv->can.state = CAN_STATE_SLEEPING;
+	/* De-initialize DCAN RAM */
+	d_can_reset_ram(priv, pdev->id, 0);
+	/* Disable the module */
+	pm_runtime_put_sync(&pdev->dev);
+	return 0;
+}
+
+static int d_can_resume(struct platform_device *pdev)
+{
+	unsigned long time_out;
+	struct net_device *ndev = platform_get_drvdata(pdev);
+	struct d_can_priv *priv = netdev_priv(ndev);
+
+	/* Enable the module */
+	pm_runtime_get_sync(&pdev->dev);
+	/* Initialize DCAN RAM */
+	d_can_reset_ram(priv, pdev->id, 1);
+
+	/* Brought back from power down mode */
+	d_can_clear_bit(priv, D_CAN_CTL, D_CAN_CTL_PDR);
+	d_can_clear_bit(priv, D_CAN_CTL, D_CAN_CTL_INIT);
+
+	/* Wait for the PDA bit to get clear */
+	time_out = jiffies + msecs_to_jiffies(D_CAN_TIMEOUT_MS);
+	while (d_can_get_bit(priv, D_CAN_ES, D_CAN_ES_PDA) &&
+				time_after(time_out, jiffies))
+		cpu_relax();
+
+	if (time_after(jiffies, time_out)) {
+		netdev_err(ndev, "Not came out from power down mode\n");
+		return -ETIMEDOUT;
+	}
+
+	if (priv->is_opened)
+		d_can_start(ndev);
+
+	priv->can.state = CAN_STATE_ERROR_ACTIVE;
+
+	if (netif_running(ndev)) {
+		netif_device_attach(ndev);
+		netif_start_queue(ndev);
+	}
+	return 0;
+}
+#else
+#define d_can_suspend NULL
+#define d_can_resume NULL
+#endif
+
+static struct platform_driver d_can_plat_driver = {
+	.driver = {
+		.name	= D_CAN_DRV_NAME,
+		.owner	= THIS_MODULE,
+	},
+	.probe		= d_can_plat_probe,
+	.remove		= __devexit_p(d_can_plat_remove),
+	.suspend	= d_can_suspend,
+	.resume		= d_can_resume,
+};
+
+static int __init d_can_plat_init(void)
+{
+	return platform_driver_register(&d_can_plat_driver);
+}
+module_init(d_can_plat_init);
+
+static void __exit d_can_plat_exit(void)
+{
+	platform_driver_unregister(&d_can_plat_driver);
+}
+module_exit(d_can_plat_exit);
+
+MODULE_AUTHOR("AnilKumar Ch <anilkumar@ti.com>");
+MODULE_LICENSE("GPL v2");
+MODULE_VERSION(D_CAN_VERSION);
+MODULE_DESCRIPTION(D_CAN_DRV_DESC);
diff --git a/include/linux/can/platform/d_can.h b/include/linux/can/platform/d_can.h
new file mode 100644
index 0000000..b6f2a3f
--- /dev/null
+++ b/include/linux/can/platform/d_can.h
@@ -0,0 +1,40 @@ 
+/*
+ * D_CAN controller driver platform header
+ *
+ * Copyright (C) 2012 Texas Instruments Incorporated - http://www.ti.com/
+ *
+ * Bosch D_CAN controller is compliant to CAN protocol version 2.0 part A and B.
+ * Bosch D_CAN user manual can be obtained from:
+ * http://www.semiconductors.bosch.de/media/en/pdf/ipmodules_1/can/
+ * d_can_users_manual_111.pdf
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation version 2.
+ *
+ * This program is distributed "as is" WITHOUT ANY WARRANTY of any
+ * kind, whether express or implied; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#ifndef __CAN_PLATFORM_TI_D_CAN_H__
+#define __CAN_PLATFORM_TI_D_CAN_H__
+
+/**
+ * struct d_can_platform_data - DCAN Platform Data
+ *
+ * @num_of_msg_objs:	Number of message objects
+ * @dma_support:	DMA support is required/not
+ * @ram_init:		DCAN RAM initialization
+ *
+ * Platform data structure to get all platform specific settings.
+ * this structure also accounts the fact that the IP may have different
+ * RAM and mailbox offsets for different SOC's
+ */
+struct d_can_platform_data {
+	unsigned int num_of_msg_objs;
+	bool dma_support;
+	void (*ram_init) (unsigned int instance, unsigned int eanble);
+};
+#endif