[U-Boot] [PATCH] sata: fix reset_sata for dwc_ahsata

[Nikita Kiryanov]

Hi Soeren,

On 11/26/2014 01:40 PM, Soeren Moch wrote:
> - fix crash when sata device is not initialized
> - remove disable_sata_clock() since it is not clear which clock for which
>    device should be disabled here
> - call disable_sata_clock() for mx6 in preboot_os instead
>
> Signed-off-by: Soeren Moch <smoch at web.de>
> ---
> Cc: Tom Rini <trini at ti.com>
> Cc: Nikita Kiryanov <nikita at compulab.co.il>
> Cc: Simon Glass <sjg at chromium.org>
> Cc: guillaume.gardet at free.fr
> Cc: Stefano Babic <sbabic at denx.de>
> ---
>   arch/arm/imx-common/cpu.c  |  3 +++
>   drivers/block/dwc_ahsata.c | 14 ++++++++------
>   2 files changed, 11 insertions(+), 6 deletions(-)
>
> diff --git a/arch/arm/imx-common/cpu.c b/arch/arm/imx-common/cpu.c
> index b58df7d..28ccd29 100644
> --- a/arch/arm/imx-common/cpu.c
> +++ b/arch/arm/imx-common/cpu.c
> @@ -206,6 +206,9 @@ void arch_preboot_os(void)
>   {
>   #if defined(CONFIG_CMD_SATA)
>   	sata_stop();
> +#if defined(CONFIG_MX6)
> +	disable_sata_clock();
> +#endif

I think a more proper way to do this might be to mirror the
init sequence completely. The simplest init sequence calls
setup_sata() somewhere before sata_initialize() is invoked,
and the distribution of labor is:
- arch/arm/imx-common/sata.c:setup_sata() Turns on clocks
- common/cmd_sata.c: sata_initialize() Calls driver init

The inverse would be:
- common/cmd_sata.c: sata_stop() Calls driver reset
- arch/arm/imx-common/sata.c:disable_sata() Turns off clocks

Thus disable_sata() would need to be defined in
arch/arm/imx-common/sata.c; it will call disable_sata_clock(),
and be used in cm_fx6's version of stop_sata().

It's a little convoluted, but consistent with the existing code
flow, and it also fixes the MX53 problems because
arch/arm/imx-common/sata.c is not compiled for this platform.

>   #endif
>   #if defined(CONFIG_VIDEO_IPUV3)
>   	/* disable video before launching O/S */
> diff --git a/drivers/block/dwc_ahsata.c b/drivers/block/dwc_ahsata.c
> index 9a2b547..9e925d1 100644
> --- a/drivers/block/dwc_ahsata.c
> +++ b/drivers/block/dwc_ahsata.c
> @@ -594,22 +594,24 @@ int init_sata(int dev)
>
>   int reset_sata(int dev)
>   {
> -	struct ahci_probe_ent *probe_ent =
> -			(struct ahci_probe_ent *)sata_dev_desc[dev].priv;
> -	struct sata_host_regs *host_mmio =
> -			(struct sata_host_regs *)probe_ent->mmio_base;
> +	struct ahci_probe_ent *probe_ent;
> +	struct sata_host_regs *host_mmio;
>
>   	if (dev < 0 || dev > (CONFIG_SYS_SATA_MAX_DEVICE - 1)) {
>   		printf("The sata index %d is out of ranges\n\r", dev);
>   		return -1;
>   	}
>
> +	probe_ent = (struct ahci_probe_ent *)sata_dev_desc[dev].priv;
> +	if (NULL == probe_ent)
> +		/* not initialized, so nothing to reset */
> +		return 0;
> +
> +	host_mmio = probe_ent->mmio_base;

The lack of casting generates a warning during compilation:
drivers/block/dwc_ahsata.c:610:12: warning: assignment makes pointer 
from integer without a cast [enabled by default]
   host_mmio = probe_ent->mmio_base;
             ^

>   	setbits_le32(&host_mmio->ghc, SATA_HOST_GHC_HR);
>   	while (readl(&host_mmio->ghc) & SATA_HOST_GHC_HR)
>   		udelay(100);
>
> -	disable_sata_clock();
> -
>   	return 0;
>   }
>
>

-- 
Regards,
Nikita Kiryanov