[U-Boot,V2,3/4] ARM: mx6: Add PCI express driver

Add PCIe driver for the Freescale i.MX6 SoC . This driver operates the
PCIe block in RC mode only, the EP mode is NOT supported. The driver is
tested with the Intel e1000 NIC driver.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Albert Aribaud <albert.u.boot@aribaud.net>
Cc: Eric Nelson <eric.nelson@boundarydevices.com>
Cc: Fabio Estevam <fabio.estevam@freescale.com>
Cc: Stefano Babic <sbabic@denx.de>
---
 arch/arm/include/asm/arch-mx6/iomux.h |  27 ++
 drivers/pci/Makefile                  |   1 +
 drivers/pci/pcie_imx.c                | 565 ++++++++++++++++++++++++++++++++++
 3 files changed, 593 insertions(+)
 create mode 100644 drivers/pci/pcie_imx.c

V2: - Check for link_in_training bit while waiting for LTSSM to finish.
    - Replace udelay(30000) with mdelay(30) in the core reset end seq.
    - Check if the link-up failed and don't probe the bus in such case
      to prevent a hang.
    - Do not assert LTSSM while the DWC core is in reset (thanks for finding
      this, Richard Zhu)

On Sat, Dec 14, 2013 at 10:25 AM, Marek Vasut <marex@denx.de> wrote:
> Add PCIe driver for the Freescale i.MX6 SoC . This driver operates the
> PCIe block in RC mode only, the EP mode is NOT supported. The driver is
> tested with the Intel e1000 NIC driver.
>
> Signed-off-by: Marek Vasut <marex@denx.de>
> Cc: Albert Aribaud <albert.u.boot@aribaud.net>
> Cc: Eric Nelson <eric.nelson@boundarydevices.com>
> Cc: Fabio Estevam <fabio.estevam@freescale.com>
> Cc: Stefano Babic <sbabic@denx.de>
> ---
>  arch/arm/include/asm/arch-mx6/iomux.h |  27 ++
>  drivers/pci/Makefile                  |   1 +
>  drivers/pci/pcie_imx.c                | 565 ++++++++++++++++++++++++++++++++++
>  3 files changed, 593 insertions(+)
>  create mode 100644 drivers/pci/pcie_imx.c
>
> V2: - Check for link_in_training bit while waiting for LTSSM to finish.
>     - Replace udelay(30000) with mdelay(30) in the core reset end seq.
>     - Check if the link-up failed and don't probe the bus in such case
>       to prevent a hang.
>     - Do not assert LTSSM while the DWC core is in reset (thanks for finding
>       this, Richard Zhu)
>
> diff --git a/arch/arm/include/asm/arch-mx6/iomux.h b/arch/arm/include/asm/arch-mx6/iomux.h
> index fe4675e..f9ee0d9 100644
> --- a/arch/arm/include/asm/arch-mx6/iomux.h
> +++ b/arch/arm/include/asm/arch-mx6/iomux.h
> @@ -15,6 +15,33 @@
>  #define IOMUXC_GPR1_OTG_ID_ENET_RX_ERR (0<<13)
>  #define IOMUXC_GPR1_OTG_ID_GPIO1       (1<<13)
>  #define IOMUXC_GPR1_OTG_ID_MASK                (1<<13)
> +#define IOMUXC_GPR1_REF_SSP_EN                 (1 << 16)
> +#define IOMUXC_GPR1_TEST_POWERDOWN             (1 << 18)
> +
> +/*
> + * IOMUXC_GPR8 bit fields
> + */
> +#define IOMUXC_GPR8_PCS_TX_DEEMPH_GEN1_MASK            (0x3f << 0)
> +#define IOMUXC_GPR8_PCS_TX_DEEMPH_GEN1_OFFSET          0
> +#define IOMUXC_GPR8_PCS_TX_DEEMPH_GEN2_3P5DB_MASK      (0x3f << 6)
> +#define IOMUXC_GPR8_PCS_TX_DEEMPH_GEN2_3P5DB_OFFSET    6
> +#define IOMUXC_GPR8_PCS_TX_DEEMPH_GEN2_6DB_MASK                (0x3f << 12)
> +#define IOMUXC_GPR8_PCS_TX_DEEMPH_GEN2_6DB_OFFSET      12
> +#define IOMUXC_GPR8_PCS_TX_SWING_FULL_MASK             (0x7f << 18)
> +#define IOMUXC_GPR8_PCS_TX_SWING_FULL_OFFSET           18
> +#define IOMUXC_GPR8_PCS_TX_SWING_LOW_MASK              (0x7f << 25)
> +#define IOMUXC_GPR8_PCS_TX_SWING_LOW_OFFSET            25
> +
> +/*
> + * IOMUXC_GPR12 bit fields
> + */
> +#define IOMUXC_GPR12_LOS_LEVEL_9               (0x9 << 4)
> +#define IOMUXC_GPR12_LOS_LEVEL_MASK            (0x1f << 4)
> +#define IOMUXC_GPR12_APPS_LTSSM_ENABLE         (1 << 10)
> +#define IOMUXC_GPR12_DEVICE_TYPE_EP            (0x0 << 12)
> +#define IOMUXC_GPR12_DEVICE_TYPE_RC            (0x2 << 12)
> +#define IOMUXC_GPR12_DEVICE_TYPE_MASK          (0xf << 12)
> +
>  /*
>   * IOMUXC_GPR13 bit fields
>   */
> diff --git a/drivers/pci/Makefile b/drivers/pci/Makefile
> index 99d51a6..565ff37 100644
> --- a/drivers/pci/Makefile
> +++ b/drivers/pci/Makefile
> @@ -9,6 +9,7 @@ obj-$(CONFIG_FSL_PCI_INIT) += fsl_pci_init.o
>  obj-$(CONFIG_PCI) += pci.o pci_auto.o
>  obj-$(CONFIG_PCI_INDIRECT_BRIDGE) += pci_indirect.o
>  obj-$(CONFIG_PCI_GT64120) += pci_gt64120.o
> +obj-$(CONFIG_PCIE_IMX) += pcie_imx.o
>  obj-$(CONFIG_FTPCI100) += pci_ftpci100.o
>  obj-$(CONFIG_IXP_PCI) += pci_ixp.o
>  obj-$(CONFIG_SH4_PCI) += pci_sh4.o
> diff --git a/drivers/pci/pcie_imx.c b/drivers/pci/pcie_imx.c
> new file mode 100644
> index 0000000..0a74867
> --- /dev/null
> +++ b/drivers/pci/pcie_imx.c
> @@ -0,0 +1,565 @@
> +/*
> + * Freescale i.MX6 PCI Express Root-Complex driver
> + *
> + * Copyright (C) 2013 Marek Vasut <marex@denx.de>
> + *
> + * Based on upstream Linux kernel driver:
> + * pci-imx6.c:         Sean Cross <xobs@kosagi.com>
> + * pcie-designware.c:  Jingoo Han <jg1.han@samsung.com>
> + *
> + * SPDX-License-Identifier:    GPL-2.0
> + */
> +
> +#include <common.h>
> +#include <pci.h>
> +#include <asm/arch/clock.h>
> +#include <asm/arch/iomux.h>
> +#include <asm/arch/crm_regs.h>
> +#include <asm/io.h>
> +#include <asm/sizes.h>
> +#include <errno.h>
> +
> +#define PCI_ACCESS_READ  0
> +#define PCI_ACCESS_WRITE 1
> +
> +#define MX6_DBI_ADDR   0x01ffc000
> +#define MX6_DBI_SIZE   0x4000
> +#define MX6_IO_ADDR    0x01000000
> +#define MX6_IO_SIZE    0x100000
> +#define MX6_MEM_ADDR   0x01100000
> +#define MX6_MEM_SIZE   0xe00000
> +#define MX6_ROOT_ADDR  0x01f00000
> +#define MX6_ROOT_SIZE  0xfc000
> +
> +/* PCIe Port Logic registers (memory-mapped) */
> +#define PL_OFFSET 0x700
> +#define PCIE_PHY_DEBUG_R0 (PL_OFFSET + 0x28)
> +#define PCIE_PHY_DEBUG_R1 (PL_OFFSET + 0x2c)
> +#define PCIE_PHY_DEBUG_R1_LINK_UP              (1 << 4)
> +#define PCIE_PHY_DEBUG_R1_LINK_IN_TRAINING     (1 << 29)
> +
> +#define PCIE_PHY_CTRL (PL_OFFSET + 0x114)
> +#define PCIE_PHY_CTRL_DATA_LOC 0
> +#define PCIE_PHY_CTRL_CAP_ADR_LOC 16
> +#define PCIE_PHY_CTRL_CAP_DAT_LOC 17
> +#define PCIE_PHY_CTRL_WR_LOC 18
> +#define PCIE_PHY_CTRL_RD_LOC 19
> +
> +#define PCIE_PHY_STAT (PL_OFFSET + 0x110)
> +#define PCIE_PHY_STAT_DATA_LOC 0
> +#define PCIE_PHY_STAT_ACK_LOC 16
> +
> +/* PHY registers (not memory-mapped) */
> +#define PCIE_PHY_RX_ASIC_OUT 0x100D
> +
> +#define PHY_RX_OVRD_IN_LO 0x1005
> +#define PHY_RX_OVRD_IN_LO_RX_DATA_EN (1 << 5)
> +#define PHY_RX_OVRD_IN_LO_RX_PLL_EN (1 << 3)
> +
> +/* iATU registers */
> +#define PCIE_ATU_VIEWPORT              0x900
> +#define PCIE_ATU_REGION_INBOUND                (0x1 << 31)
> +#define PCIE_ATU_REGION_OUTBOUND       (0x0 << 31)
> +#define PCIE_ATU_REGION_INDEX1         (0x1 << 0)
> +#define PCIE_ATU_REGION_INDEX0         (0x0 << 0)
> +#define PCIE_ATU_CR1                   0x904
> +#define PCIE_ATU_TYPE_MEM              (0x0 << 0)
> +#define PCIE_ATU_TYPE_IO               (0x2 << 0)
> +#define PCIE_ATU_TYPE_CFG0             (0x4 << 0)
> +#define PCIE_ATU_TYPE_CFG1             (0x5 << 0)
> +#define PCIE_ATU_CR2                   0x908
> +#define PCIE_ATU_ENABLE                        (0x1 << 31)
> +#define PCIE_ATU_BAR_MODE_ENABLE       (0x1 << 30)
> +#define PCIE_ATU_LOWER_BASE            0x90C
> +#define PCIE_ATU_UPPER_BASE            0x910
> +#define PCIE_ATU_LIMIT                 0x914
> +#define PCIE_ATU_LOWER_TARGET          0x918
> +#define PCIE_ATU_BUS(x)                        (((x) & 0xff) << 24)
> +#define PCIE_ATU_DEV(x)                        (((x) & 0x1f) << 19)
> +#define PCIE_ATU_FUNC(x)               (((x) & 0x7) << 16)
> +#define PCIE_ATU_UPPER_TARGET          0x91C
> +
> +/*
> + * PHY access functions
> + */
> +static int pcie_phy_poll_ack(void __iomem *dbi_base, int exp_val)
> +{
> +       u32 val;
> +       u32 max_iterations = 10;
> +       u32 wait_counter = 0;
> +
> +       do {
> +               val = readl(dbi_base + PCIE_PHY_STAT);
> +               val = (val >> PCIE_PHY_STAT_ACK_LOC) & 0x1;
> +               wait_counter++;
> +
> +               if (val == exp_val)
> +                       return 0;
> +
> +               udelay(1);
> +       } while (wait_counter < max_iterations);
> +
> +       return -ETIMEDOUT;
> +}
> +
> +static int pcie_phy_wait_ack(void __iomem *dbi_base, int addr)
> +{
> +       u32 val;
> +       int ret;
> +
> +       val = addr << PCIE_PHY_CTRL_DATA_LOC;
> +       writel(val, dbi_base + PCIE_PHY_CTRL);
> +
> +       val |= (0x1 << PCIE_PHY_CTRL_CAP_ADR_LOC);
> +       writel(val, dbi_base + PCIE_PHY_CTRL);
> +
> +       ret = pcie_phy_poll_ack(dbi_base, 1);
> +       if (ret)
> +               return ret;
> +
> +       val = addr << PCIE_PHY_CTRL_DATA_LOC;
> +       writel(val, dbi_base + PCIE_PHY_CTRL);
> +
> +       ret = pcie_phy_poll_ack(dbi_base, 0);
> +       if (ret)
> +               return ret;
> +
> +       return 0;
> +}
> +
> +/* Read from the 16-bit PCIe PHY control registers (not memory-mapped) */
> +static int pcie_phy_read(void __iomem *dbi_base, int addr , int *data)
> +{
> +       u32 val, phy_ctl;
> +       int ret;
> +
> +       ret = pcie_phy_wait_ack(dbi_base, addr);
> +       if (ret)
> +               return ret;
> +
> +       /* assert Read signal */
> +       phy_ctl = 0x1 << PCIE_PHY_CTRL_RD_LOC;
> +       writel(phy_ctl, dbi_base + PCIE_PHY_CTRL);
> +
> +       ret = pcie_phy_poll_ack(dbi_base, 1);
> +       if (ret)
> +               return ret;
> +
> +       val = readl(dbi_base + PCIE_PHY_STAT);
> +       *data = val & 0xffff;
> +
> +       /* deassert Read signal */
> +       writel(0x00, dbi_base + PCIE_PHY_CTRL);
> +
> +       ret = pcie_phy_poll_ack(dbi_base, 0);
> +       if (ret)
> +               return ret;
> +
> +       return 0;
> +}
> +
> +static int pcie_phy_write(void __iomem *dbi_base, int addr, int data)
> +{
> +       u32 var;
> +       int ret;
> +
> +       /* write addr */
> +       /* cap addr */
> +       ret = pcie_phy_wait_ack(dbi_base, addr);
> +       if (ret)
> +               return ret;
> +
> +       var = data << PCIE_PHY_CTRL_DATA_LOC;
> +       writel(var, dbi_base + PCIE_PHY_CTRL);
> +
> +       /* capture data */
> +       var |= (0x1 << PCIE_PHY_CTRL_CAP_DAT_LOC);
> +       writel(var, dbi_base + PCIE_PHY_CTRL);
> +
> +       ret = pcie_phy_poll_ack(dbi_base, 1);
> +       if (ret)
> +               return ret;
> +
> +       /* deassert cap data */
> +       var = data << PCIE_PHY_CTRL_DATA_LOC;
> +       writel(var, dbi_base + PCIE_PHY_CTRL);
> +
> +       /* wait for ack de-assertion */
> +       ret = pcie_phy_poll_ack(dbi_base, 0);
> +       if (ret)
> +               return ret;
> +
> +       /* assert wr signal */
> +       var = 0x1 << PCIE_PHY_CTRL_WR_LOC;
> +       writel(var, dbi_base + PCIE_PHY_CTRL);
> +
> +       /* wait for ack */
> +       ret = pcie_phy_poll_ack(dbi_base, 1);
> +       if (ret)
> +               return ret;
> +
> +       /* deassert wr signal */
> +       var = data << PCIE_PHY_CTRL_DATA_LOC;
> +       writel(var, dbi_base + PCIE_PHY_CTRL);
> +
> +       /* wait for ack de-assertion */
> +       ret = pcie_phy_poll_ack(dbi_base, 0);
> +       if (ret)
> +               return ret;
> +
> +       writel(0x0, dbi_base + PCIE_PHY_CTRL);
> +
> +       return 0;
> +}
> +
> +static int imx6_pcie_link_up(void)
> +{
> +       u32 rc, ltssm;
> +       int rx_valid, temp;
> +
> +       /* link is debug bit 36, debug register 1 starts at bit 32 */
> +       rc = readl(MX6_DBI_ADDR + PCIE_PHY_DEBUG_R1);
> +       if ((rc & PCIE_PHY_DEBUG_R1_LINK_UP) &&
> +           !(rc & PCIE_PHY_DEBUG_R1_LINK_IN_TRAINING))
> +               return -EAGAIN;
> +
> +       /*
> +        * From L0, initiate MAC entry to gen2 if EP/RC supports gen2.
> +        * Wait 2ms (LTSSM timeout is 24ms, PHY lock is ~5us in gen2).
> +        * If (MAC/LTSSM.state == Recovery.RcvrLock)
> +        * && (PHY/rx_valid==0) then pulse PHY/rx_reset. Transition
> +        * to gen2 is stuck
> +        */
> +       pcie_phy_read((void *)MX6_DBI_ADDR, PCIE_PHY_RX_ASIC_OUT, &rx_valid);
> +       ltssm = readl(MX6_DBI_ADDR + PCIE_PHY_DEBUG_R0) & 0x3F;
> +
> +       if (rx_valid & 0x01)
> +               return 0;
> +
> +       if (ltssm != 0x0d)
> +               return 0;
> +
> +       printf("transition to gen2 is stuck, reset PHY!\n");
> +
> +       pcie_phy_read((void *)MX6_DBI_ADDR, PHY_RX_OVRD_IN_LO, &temp);
> +       temp |= (PHY_RX_OVRD_IN_LO_RX_DATA_EN | PHY_RX_OVRD_IN_LO_RX_PLL_EN);
> +       pcie_phy_write((void *)MX6_DBI_ADDR, PHY_RX_OVRD_IN_LO, temp);
> +
> +       udelay(3000);
> +
> +       pcie_phy_read((void *)MX6_DBI_ADDR, PHY_RX_OVRD_IN_LO, &temp);
> +       temp &= ~(PHY_RX_OVRD_IN_LO_RX_DATA_EN | PHY_RX_OVRD_IN_LO_RX_PLL_EN);
> +       pcie_phy_write((void *)MX6_DBI_ADDR, PHY_RX_OVRD_IN_LO, temp);
> +
> +       return 0;
> +}
> +
> +/*
> + * iATU region setup
> + */
> +static int imx_pcie_regions_setup(void)
> +{
> +       /*
> +        * i.MX6 defines 16MB in the AXI address map for PCIe.
> +        *
> +        * That address space excepted the pcie registers is
> +        * split and defined into different regions by iATU,
> +        * with sizes and offsets as follows:
> +        *
> +        * 0x0100_0000 --- 0x010F_FFFF 1MB IORESOURCE_IO
> +        * 0x0110_0000 --- 0x01EF_FFFF 14MB IORESOURCE_MEM
> +        * 0x01F0_0000 --- 0x01FF_FFFF 1MB Cfg + Registers
> +        */
> +
> +       /* CMD reg:I/O space, MEM space, and Bus Master Enable */
> +       setbits_le32(MX6_DBI_ADDR | PCI_COMMAND,
> +                    PCI_COMMAND_IO | PCI_COMMAND_MEMORY | PCI_COMMAND_MASTER);
> +
> +       /* Set the CLASS_REV of RC CFG header to PCI_CLASS_BRIDGE_PCI */
> +       setbits_le32(MX6_DBI_ADDR + PCI_CLASS_REVISION,
> +                    PCI_CLASS_BRIDGE_PCI << 16);
> +
> +       /* Region #0 is used for Outbound CFG space access. */
> +       writel(0, MX6_DBI_ADDR + PCIE_ATU_VIEWPORT);
> +
> +       writel(MX6_ROOT_ADDR, MX6_DBI_ADDR + PCIE_ATU_LOWER_BASE);
> +       writel(0, MX6_DBI_ADDR + PCIE_ATU_UPPER_BASE);
> +       writel(MX6_ROOT_ADDR + MX6_ROOT_SIZE, MX6_DBI_ADDR + PCIE_ATU_LIMIT);
> +
> +       writel(0, MX6_DBI_ADDR + PCIE_ATU_LOWER_TARGET);
> +       writel(0, MX6_DBI_ADDR + PCIE_ATU_UPPER_TARGET);
> +       writel(PCIE_ATU_TYPE_CFG0, MX6_DBI_ADDR + PCIE_ATU_CR1);
> +       writel(PCIE_ATU_ENABLE, MX6_DBI_ADDR + PCIE_ATU_CR2);
> +
> +       return 0;
> +}
> +
> +/*
> + * PCI Express accessors
> + */
> +static uint32_t get_bus_address(pci_dev_t d, int where)
> +{
> +       uint32_t va_address;
> +
> +       /* Reconfigure Region #0 */
> +       writel(0, MX6_DBI_ADDR + PCIE_ATU_VIEWPORT);
> +
> +       if (PCI_BUS(d) < 2)
> +               writel(PCIE_ATU_TYPE_CFG0, MX6_DBI_ADDR + PCIE_ATU_CR1);
> +       else
> +               writel(PCIE_ATU_TYPE_CFG1, MX6_DBI_ADDR + PCIE_ATU_CR1);
> +
> +       if (PCI_BUS(d) == 0) {
> +               va_address = MX6_DBI_ADDR;
> +       } else {
> +               writel(d << 8, MX6_DBI_ADDR + PCIE_ATU_LOWER_TARGET);
> +               va_address = MX6_IO_ADDR + SZ_16M - SZ_1M;
> +       }
> +
> +       va_address += (where & ~0x3);
> +
> +       return va_address;
> +}
> +
> +static int imx_pcie_addr_valid(pci_dev_t d)
> +{
> +       if ((PCI_BUS(d) == 0) && (PCI_DEV(d) > 1))
> +               return -EINVAL;
> +       if ((PCI_BUS(d) == 1) && (PCI_DEV(d) > 0))
> +               return -EINVAL;
> +       return 0;
> +}
> +
> +/*
> + * Replace the original ARM DABT handler with a simple jump-back one.
> + *
> + * The problem here is that if we have a PCIe bridge attached to this PCIe
> + * controller, but no PCIe device is connected to the bridges' downstream
> + * port, the attempt to read/write from/to the config space will produce
> + * a DABT. This is a behavior of the controller and can not be disabled
> + * unfortuatelly.
> + *
> + * To work around the problem, we backup the current DABT handler address
> + * and replace it with our own DABT handler, which only bounces right back
> + * into the code.
> + */
> +static void imx_pcie_fix_dabt_handler(bool set)
> +{
> +       extern uint32_t *_data_abort;

Not a good idea to use extern in .c - any comments?

On Saturday, December 14, 2013 at 06:23:30 AM, Jagan Teki wrote:
[...]
> > +/*
> > + * Replace the original ARM DABT handler with a simple jump-back one.
> > + *
> > + * The problem here is that if we have a PCIe bridge attached to this
> > PCIe + * controller, but no PCIe device is connected to the bridges'
> > downstream + * port, the attempt to read/write from/to the config space
> > will produce + * a DABT. This is a behavior of the controller and can
> > not be disabled + * unfortuatelly.
> > + *
> > + * To work around the problem, we backup the current DABT handler
> > address + * and replace it with our own DABT handler, which only bounces
> > right back + * into the code.
> > + */
> > +static void imx_pcie_fix_dabt_handler(bool set)
> > +{
> > +       extern uint32_t *_data_abort;
> 
> Not a good idea to use extern in .c - any comments?

Why is half of the CC dropped from this email? (restored by hand)

As for the extern, there is no better way to replace the DABT handler (see patch 
0001) for this purpose . This will be changed later though, once Alberts' 
patches land , but that's a post-2014.01 matter.

Best regards,
Marek Vasut

On Sat, Dec 14, 2013 at 11:03 AM, Marek Vasut <marex@denx.de> wrote:
> On Saturday, December 14, 2013 at 06:23:30 AM, Jagan Teki wrote:
> [...]
>> > +/*
>> > + * Replace the original ARM DABT handler with a simple jump-back one.
>> > + *
>> > + * The problem here is that if we have a PCIe bridge attached to this
>> > PCIe + * controller, but no PCIe device is connected to the bridges'
>> > downstream + * port, the attempt to read/write from/to the config space
>> > will produce + * a DABT. This is a behavior of the controller and can
>> > not be disabled + * unfortuatelly.
>> > + *
>> > + * To work around the problem, we backup the current DABT handler
>> > address + * and replace it with our own DABT handler, which only bounces
>> > right back + * into the code.
>> > + */
>> > +static void imx_pcie_fix_dabt_handler(bool set)
>> > +{
>> > +       extern uint32_t *_data_abort;
>>
>> Not a good idea to use extern in .c - any comments?
>
> Why is half of the CC dropped from this email? (restored by hand)
Sorry, some accident.

>
> As for the extern, there is no better way to replace the DABT handler (see patch
> 0001) for this purpose . This will be changed later though, once Alberts'
> patches land , but that's a post-2014.01 matter.

OK.

And one more thing, where is the patch V2, 1/4 - I couldn't find it.

On Saturday, December 14, 2013 at 09:52:21 AM, Jagan Teki wrote:
> On Sat, Dec 14, 2013 at 11:03 AM, Marek Vasut <marex@denx.de> wrote:
> > On Saturday, December 14, 2013 at 06:23:30 AM, Jagan Teki wrote:
> > [...]
> > 
> >> > +/*
> >> > + * Replace the original ARM DABT handler with a simple jump-back one.
> >> > + *
> >> > + * The problem here is that if we have a PCIe bridge attached to this
> >> > PCIe + * controller, but no PCIe device is connected to the bridges'
> >> > downstream + * port, the attempt to read/write from/to the config
> >> > space will produce + * a DABT. This is a behavior of the controller
> >> > and can not be disabled + * unfortuatelly.
> >> > + *
> >> > + * To work around the problem, we backup the current DABT handler
> >> > address + * and replace it with our own DABT handler, which only
> >> > bounces right back + * into the code.
> >> > + */
> >> > +static void imx_pcie_fix_dabt_handler(bool set)
> >> > +{
> >> > +       extern uint32_t *_data_abort;
> >> 
> >> Not a good idea to use extern in .c - any comments?
> > 
> > Why is half of the CC dropped from this email? (restored by hand)
> 
> Sorry, some accident.
> 
> > As for the extern, there is no better way to replace the DABT handler
> > (see patch 0001) for this purpose . This will be changed later though,
> > once Alberts' patches land , but that's a post-2014.01 matter.
> 
> OK.
> 
> And one more thing, where is the patch V2, 1/4 - I couldn't find it.

Nowhere, 1/4 didn't change.

Best regards,
Marek Vasut

Hi Marek,

On 14/12/2013 05:55, Marek Vasut wrote:
> Add PCIe driver for the Freescale i.MX6 SoC . This driver operates the
> PCIe block in RC mode only, the EP mode is NOT supported. The driver is
> tested with the Intel e1000 NIC driver.
>
> Signed-off-by: Marek Vasut <marex@denx.de>
> Cc: Albert Aribaud <albert.u.boot@aribaud.net>
> Cc: Eric Nelson <eric.nelson@boundarydevices.com>
> Cc: Fabio Estevam <fabio.estevam@freescale.com>
> Cc: Stefano Babic <sbabic@denx.de>
>

Applied to u-boot-imx, thanks !

Best regards,
Stefano Babic



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