ppc/sata-fsl: orphan config value: CONFIG_MPC8315_DS

[Li Yang-R58472]

> -----Original Message-----
> From: Anthony Foiani [mailto:tkil at scrye.com]
> Sent: Friday, May 18, 2012 1:08 AM
> To: linuxppc-dev at lists.ozlabs.org
> Cc: ashish kalra; Li Yang-R58472; Jeff Garzik; Robert P.J.Day; Adrian
> Bunk
> Subject: ppc/sata-fsl: orphan config value: CONFIG_MPC8315_DS
> 
> 
> Greetings.
> 
> I was occasionally running into problems at boot time on an MPC8315-based
> board (derived from the MPC831xRDB, apparently), using SATA to talk to an
> SSD.  My vendor suggested that I enable CONFIG_MPC8315_DS.
> 
> That symbol is only found once in the entire kernel codebase:
> 
>   $ git checkout v3.4-rc7
>   HEAD is now at 36be505... Linux 3.4-rc7
> 
>   $ git grep -nH CONFIG_MPC8315_DS
>   drivers/ata/sata_fsl.c:729:#ifdef CONFIG_MPC8315_DS
> 
> There is no kconfig support for it at all.
> 
> It was added in 2007; further, this is the only commit in the entire git
> history that contains this string:
> 
>    commit e7eac96e8f0e57a6e9f94943557bc2b23be31471
>    Author: ashish kalra <ashish.kalra at freescale.com>
>    Date:   Wed Oct 31 19:28:02 2007 +0800
> 
>        ata/sata_fsl: Move MPC8315DS link speed limit workaround to
> specific ifdef
> 
>        Signed-off-by: ashish kalra <ashish.kalra at freescale.com>
>        Signed-off-by: Li Yang <leoli at freescale.com>
>        Signed-off-by: Jeff Garzik <jeff at garzik.org>
> 
>    diff --git a/drivers/ata/sata_fsl.c b/drivers/ata/sata_fsl.c
>    index 5892472..e076e1f 100644
>    --- a/drivers/ata/sata_fsl.c
>    +++ b/drivers/ata/sata_fsl.c
>    @@ -652,6 +652,7 @@ static int sata_fsl_port_start(struct ata_port *ap)
>            VPRINTK("HControl = 0x%x\n", ioread32(hcr_base + HCONTROL));
>            VPRINTK("CHBA  = 0x%x\n", ioread32(hcr_base + CHBA));
> 
>    +#ifdef CONFIG_MPC8315_DS
>            /*
>             * Workaround for 8315DS board 3gbps link-up issue,
>             * currently limit SATA port to GEN1 speed
>    @@ -664,6 +665,7 @@ static int sata_fsl_port_start(struct ata_port *ap)
>            sata_fsl_scr_read(ap, SCR_CONTROL, &temp);
>            dev_printk(KERN_WARNING, dev, "scr_control, speed limited
> to %x\n",
>                            temp);
>    +#endif
> 
>            return 0;
>     }
> 
> This otherwise-unsupported variable was noted by Robert Day in 2008;
> Adrian Bunk suggested a patch, but the Freescale folks said that it was
> for a not-yet-mainlined board, so the patch was dropped:
> 
>    http://marc.info/?l=linux-ide&m=121783965216004&w=2
> 
> As Robert notied again in 2010, it still wasn't mainlined:
> 
>    http://marc.info/?l=linux-ide&m=121783965216004&w=2
> 
> And, obviously, it still isn't today.
> 
> Can the Freescale people tell us exactly what we should be testing to
> determine when to enforce this restriction?  A config variable that
> points to a non-existent board doesn't seem much help.

Thanks for bringing it up again.  Looks like we do have a problem here.

Btw, did it help with your problem by enabling it?

Leo