[v2,3/3] ahci_platform: add support for CNS3xxx SoC devices

From: Mac Lin <mkl0301@gmail.com>

CNS3xxx override the softreset function of ahci_platform ahci_softreset by
cns3xxx_ahci_softreset, which would retry ahci_do_softreset again with pmp=0 if
pmp=15 failed, for the controller has problem receiving D2H Reg FIS of the

On Wed, Jan 05, 2011 at 01:43:07PM +0800, mkl0301@gmail.com wrote:
> From: Mac Lin <mkl0301@gmail.com>
> 
> CNS3xxx override the softreset function of ahci_platform ahci_softreset by
> cns3xxx_ahci_softreset, which would retry ahci_do_softreset again with pmp=0 if
> pmp=15 failed, for the controller has problem receiving D2H Reg FIS of the
> different PMP setting of the previous sent H2D Reg FIS.
> 
> Following describe the isssue with original ahci_platform driver on
> linux-2.6.37-rc3, arm/cns3xxx.
> 
> If CONFIG_SATA_PMP is enabled, while not using multiplier and connect the disks
> directly to the board, the disk cannot be found due to software reset always
> failed.
> 
>     ahci ahci.0: forcing PORTS_IMPL to 0x3
>     ahci ahci.0: AHCI 0001.0100 32 slots 2 ports 3 Gbps 0x3 impl platform mode
>     ahci ahci.0: flags: ncq sntf pm led clo only pmp pio slum part ccc
>     scsi0 : ahci_platform
>     scsi1 : ahci_platform
>     ata1: SATA max UDMA/133 irq_stat 0x00400040, connection status changed irq 65
>     ata2: SATA max UDMA/133 mmio [mem 0x83000000-0x83ffffff] port 0x180 irq 65
>     ata2: SATA link down (SStatus 0 SControl 300)
>     ata1: link is slow to respond, please be patient (ready=0)
>     ata1: softreset failed (device not ready)
>     ata1: link is slow to respond, please be patient (ready=0)
>     ata1: softreset failed (device not ready)
>     ata1: link is slow to respond, please be patient (ready=0)
>     ata1: softreset failed (device not ready)
>     ata1: limiting SATA link speed to 1.5 Gbps
>     ata1: SATA link down (SStatus 1 SControl 310)
> 
> While using multiplier with CONFIG_SATA_PMP enabled, or using disks directly
> without CONFIG_SATA_PMP have no issue. It seems the device is sending D2H Reg
> FIS, but controller is not reflecting it on any known means.
> 
> Signed-off-by: Mac Lin <mkl0301@gmail.com>

I like this patch, thanks Mac! Few cosmetic comments below.

> ---
>  arch/arm/mach-cns3xxx/devices.c |    2 +-
>  drivers/ata/Kconfig             |   11 +++++++
>  drivers/ata/Makefile            |    1 +
>  drivers/ata/ahci_cns3xxx.c      |   62 +++++++++++++++++++++++++++++++++++++++
>  drivers/ata/ahci_pltfm.c        |    3 ++
>  drivers/ata/ahci_pltfm.h        |    2 +
>  6 files changed, 80 insertions(+), 1 deletions(-)
>  create mode 100644 drivers/ata/ahci_cns3xxx.c
> 
> diff --git a/arch/arm/mach-cns3xxx/devices.c b/arch/arm/mach-cns3xxx/devices.c
> index 50b4d31..b496f02 100644
> --- a/arch/arm/mach-cns3xxx/devices.c
> +++ b/arch/arm/mach-cns3xxx/devices.c
> @@ -40,7 +40,7 @@ static struct resource cns3xxx_ahci_resource[] = {
>  static u64 cns3xxx_ahci_dmamask = DMA_BIT_MASK(32);
>  
>  static struct platform_device cns3xxx_ahci_pdev = {
> -	.name		= "ahci",
> +	.name		= "ahci-cns3xxx",
>  	.id		= 0,
>  	.resource	= cns3xxx_ahci_resource,
>  	.num_resources	= ARRAY_SIZE(cns3xxx_ahci_resource),
> diff --git a/drivers/ata/Kconfig b/drivers/ata/Kconfig
> index 36e2319..5d8b1a3 100644
> --- a/drivers/ata/Kconfig
> +++ b/drivers/ata/Kconfig
> @@ -75,6 +75,17 @@ config SATA_AHCI_PLATFORM
>  
>  	  If unsure, say N.
>  
> +config SATA_AHCI_CNS3XXX
> +	bool "AHCI Support on the Cavium Networks CNS3xxx SOC"
> +	depends on ARCH_CNS3XXX
> +	depends on SATA_AHCI_PLATFORM
> +	help
> +	  This option enables AHCI platform driver to support CNS3xxx
> +	  System-on-Chip devices. This is only needed when using CNS3xxx AHCI
> +	  controller.
> +
> +	  If unsure, say N.
> +
>  config SATA_FSL
>  	tristate "Freescale 3.0Gbps SATA support"
>  	depends on FSL_SOC
> diff --git a/drivers/ata/Makefile b/drivers/ata/Makefile
> index 5b62be8..a0745e5 100644
> --- a/drivers/ata/Makefile
> +++ b/drivers/ata/Makefile
> @@ -100,6 +100,7 @@ obj-$(CONFIG_PATA_LEGACY)	+= pata_legacy.o
>  
>  obj-$(CONFIG_SATA_AHCI_PLATFORM) 		+= ahci_platform.o libahci.o
>  ahci_platform-y					:= ahci_pltfm.o
> +ahci_platform-$(CONFIG_SATA_AHCI_CNS3XXX) 	+= ahci_cns3xxx.o
>  
>  libata-y	:= libata-core.o libata-scsi.o libata-eh.o libata-transport.o
>  libata-$(CONFIG_ATA_SFF)	+= libata-sff.o
> diff --git a/drivers/ata/ahci_cns3xxx.c b/drivers/ata/ahci_cns3xxx.c
> new file mode 100644
> index 0000000..f7a238e
> --- /dev/null
> +++ b/drivers/ata/ahci_cns3xxx.c
> @@ -0,0 +1,62 @@
> +/*
> + * AHCI support for CNS3xxx SoC
> + *
> + * Copyright 2010 MontaVista Software, LLC.
> + * Copyright 2010 Cavium Networks
> + *
> + * Authors: Anton Vorontsov <avorontsov@mvista.com>
> + *	    Mac Lin <mkl0301@gmail.com>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + */
> +
> +#include <linux/libata.h>
> +#include <linux/ahci_platform.h>
> +#include "ahci.h"
> +
> +static int cns3xxx_ahci_softreset(struct ata_link *link, unsigned int *class,
> +			  unsigned long deadline)
> +{
> +	int pmp = sata_srst_pmp(link);
> +	int ret;
> +	DPRINTK("ENTER\n")

I'd remove this dprintk. Or at least, put an empty line after
'int ret;'

> +
> +	ret = ahci_do_softreset(link, class, pmp, deadline, ahci_check_ready);
> +	if (pmp && ret)
> +		return ahci_do_softreset(link, class, 0, deadline,
> +			ahci_check_ready);
> +	else
> +		return ret;

No need for 'else'

> +}
> +
> +static int cns3xxx_ahci_init(struct device *dev, void __iomem *addr)
> +{
> +	/*
> +	 * TODO: move cns3xxx_ahci_init to here after cns3xxx_pwr*() calls are
> +	 * thread-safe
> +	 */
> +
> +	return 0;
> +}

This is effectively no-op, just remove this function completely.
You may move the comment on top of the file, if you like.

> +static struct ata_port_operations cns3xxx_ahci_ops = {
> +	.inherits		= &ahci_ops,
> +	.softreset		= cns3xxx_ahci_softreset,
> +};
> +
> +static const struct ata_port_info cns3xxx_ata_port_info = {
> +	.flags		= AHCI_FLAG_COMMON,
> +	.pio_mask	= ATA_PIO4,
> +	.udma_mask	= ATA_UDMA6,
> +	.port_ops	= &cns3xxx_ahci_ops,
> +};
> +
> +struct ahci_platform_data cns3xxx_ahci_platform_data = {
> +	.init		= cns3xxx_ahci_init,
> +	.ata_port_info	= &cns3xxx_ata_port_info,
> +	.force_port_map = 0,
> +	.mask_port_map = 0,

You don't actually need to fill mask_port_map, as well as
force_port_map. cns3xxx_ahci_platform_data is global, thus will
initialize with zeroes.

> +};
> +

No need for this empty line (i.e. at the end of the file).

Thanks!