[v3] driver/FSL SATA:Fix wrong Device Error Register usage

When a single device error is detected, the device under the error is indicated
by the error bit set in the DER. There is a one to one mapping between register
bit and devices on Port multiplier(PMP) i.e. bit 0 represents PMP device 0 and
bit 1 represents PMP device 1 etc.

Current implementation treats Device error register value as device number not
set of bits representing multiple device on PMP. It is changed to consider bit
level.
No need to check for each set bit as all command is going to be aborted.

Signed-off-by: Ashish Kalra <B00888@freescale.com>
Signed-off-by: Prabhakar Kushwaha <prabhakar@freescale.com>
---

 git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6.git (branch master)

 This patch is already gone through review of linuxppc-dev mail list.
 Making CC linuxppc-dev@lists.ozlabs.org

 Changes for v2: Incorporated Sergei Shtylyov's comment
	- Put space after -
	- added a line
 Changes for v3: Incorporated David Laight's comment
 	- Condition check for dereg 0 for hardware error

 drivers/ata/sata_fsl.c |    7 +++++--
 1 files changed, 5 insertions(+), 2 deletions(-)

Hi Jeff,

I am not finding any new comments on this.

Could you please ACK this patch so that it can be applied on external list. 

--Prabhakar


> -----Original Message-----
> From: Kushwaha Prabhakar-B32579
> Sent: Wednesday, March 09, 2011 12:47 PM
> To: linux-ide@vger.kernel.org
> Cc: linuxppc-dev@lists.ozlabs.org; jgarzik@pobox.com;
> meet2prabhu@gmail.com; Kushwaha Prabhakar-B32579; Kalra Ashish-B00888
> Subject: [PATCH][v3] driver/FSL SATA:Fix wrong Device Error Register
> usage
> 
> When a single device error is detected, the device under the error is
> indicated by the error bit set in the DER. There is a one to one mapping
> between register bit and devices on Port multiplier(PMP) i.e. bit 0
> represents PMP device 0 and bit 1 represents PMP device 1 etc.
> 
> Current implementation treats Device error register value as device
> number not set of bits representing multiple device on PMP. It is changed
> to consider bit level.
> No need to check for each set bit as all command is going to be aborted.
> 
> Signed-off-by: Ashish Kalra <B00888@freescale.com>
> Signed-off-by: Prabhakar Kushwaha <prabhakar@freescale.com>
> ---
> 
>  git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6.git
> (branch master)
> 
>  This patch is already gone through review of linuxppc-dev mail list.
>  Making CC linuxppc-dev@lists.ozlabs.org
> 
>  Changes for v2: Incorporated Sergei Shtylyov's comment
> 	- Put space after -
> 	- added a line
>  Changes for v3: Incorporated David Laight's comment
>  	- Condition check for dereg 0 for hardware error
> 
>  drivers/ata/sata_fsl.c |    7 +++++--
>  1 files changed, 5 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/ata/sata_fsl.c b/drivers/ata/sata_fsl.c index
> b0214d0..ad84ddc 100644
> --- a/drivers/ata/sata_fsl.c
> +++ b/drivers/ata/sata_fsl.c
> @@ -1040,12 +1040,15 @@ static void sata_fsl_error_intr(struct ata_port
> *ap)
> 
>  		/* find out the offending link and qc */
>  		if (ap->nr_pmp_links) {
> +			unsigned int dev_num;
> +
>  			dereg = ioread32(hcr_base + DE);
>  			iowrite32(dereg, hcr_base + DE);
>  			iowrite32(cereg, hcr_base + CE);
> 
> -			if (dereg < ap->nr_pmp_links) {
> -				link = &ap->pmp_link[dereg];
> +			dev_num = ffs(dereg) - 1;
> +			if (dev_num < ap->nr_pmp_links && dereg != 0) {
> +				link = &ap->pmp_link[dev_num];
>  				ehi = &link->eh_info;
>  				qc = ata_qc_from_tag(ap, link->active_tag);
>  				/*
> --
> 1.7.3

On 03/09/2011 02:17 AM, Prabhakar Kushwaha wrote:
> When a single device error is detected, the device under the error is indicated
> by the error bit set in the DER. There is a one to one mapping between register
> bit and devices on Port multiplier(PMP) i.e. bit 0 represents PMP device 0 and
> bit 1 represents PMP device 1 etc.
>
> Current implementation treats Device error register value as device number not
> set of bits representing multiple device on PMP. It is changed to consider bit
> level.
> No need to check for each set bit as all command is going to be aborted.
>
> Signed-off-by: Ashish Kalra<B00888@freescale.com>
> Signed-off-by: Prabhakar Kushwaha<prabhakar@freescale.com>
> ---
>
>   git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6.git (branch master)
>
>   This patch is already gone through review of linuxppc-dev mail list.
>   Making CC linuxppc-dev@lists.ozlabs.org
>
>   Changes for v2: Incorporated Sergei Shtylyov's comment
> 	- Put space after -
> 	- added a line
>   Changes for v3: Incorporated David Laight's comment
>   	- Condition check for dereg 0 for hardware error
>
>   drivers/ata/sata_fsl.c |    7 +++++--
>   1 files changed, 5 insertions(+), 2 deletions(-)

applied