Patchwork [v2] driver/FSL SATA:Fix wrong Device Error Register usage

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Submitter Prabhakar Kushwaha
Date Feb. 21, 2011, 9:57 a.m.
Message ID <1298282264-1222-1-git-send-email-prabhakar@freescale.com>
Download mbox | patch
Permalink /patch/83810/
State Not Applicable
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Comments

Prabhakar Kushwaha - Feb. 21, 2011, 9:57 a.m.
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: Prabhakar Kushwaha <prabhakar@freescale.com>
Signed-off-by: Ashish Kalra <B00888@freescale.com>
---
 git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6.git (branch master)

 Changes for v1: Incorporated David Laight's comment
 	- Single usage of ffs()

 Changes for v2: Incorporated David Laight's comment
 	- Changed type of dev_num to unsigned

 drivers/ata/sata_fsl.c |    6 ++++--
 1 files changed, 4 insertions(+), 2 deletions(-)
Benjamin Herrenschmidt - March 2, 2011, 3:25 a.m.
On Mon, 2011-02-21 at 15:27 +0530, 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.

It might help to send those patches to the linux-ide mailing list and
appropriate libata maintainers in addition to CC'ing linuxppc-dev.

Cheers,
Ben.

> 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: Prabhakar Kushwaha <prabhakar@freescale.com>
> Signed-off-by: Ashish Kalra <B00888@freescale.com>
> ---
>  git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6.git (branch master)
> 
>  Changes for v1: Incorporated David Laight's comment
>  	- Single usage of ffs()
> 
>  Changes for v2: Incorporated David Laight's comment
>  	- Changed type of dev_num to unsigned
> 
>  drivers/ata/sata_fsl.c |    6 ++++--
>  1 files changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/ata/sata_fsl.c b/drivers/ata/sata_fsl.c
> index b0214d0..895771c 100644
> --- a/drivers/ata/sata_fsl.c
> +++ b/drivers/ata/sata_fsl.c
> @@ -1040,12 +1040,14 @@ 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) {
> +				link = &ap->pmp_link[dev_num];
>  				ehi = &link->eh_info;
>  				qc = ata_qc_from_tag(ap, link->active_tag);
>  				/*
Prabhakar Kushwaha - March 2, 2011, 5:22 a.m.
> -----Original Message-----
> From: Benjamin Herrenschmidt [mailto:benh@kernel.crashing.org]
> Sent: Wednesday, March 02, 2011 8:56 AM
> To: Kushwaha Prabhakar-B32579
> Cc: linuxppc-dev@lists.ozlabs.org; meet2prabhu@gmail.com; Kalra Ashish-
> B00888
> Subject: Re: [PATCH][v2] driver/FSL SATA:Fix wrong Device Error Register
> usage
> 
> On Mon, 2011-02-21 at 15:27 +0530, 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.
> 
> It might help to send those patches to the linux-ide mailing list and
> appropriate libata maintainers in addition to CC'ing linuxppc-dev.
> 
Thanks Benjamin!!
I will take care your point in near future.

--Prabhakar

> > 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: Prabhakar Kushwaha <prabhakar@freescale.com>
> > Signed-off-by: Ashish Kalra <B00888@freescale.com>
> > ---
> >  git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6.git
> > (branch master)
> >
> >  Changes for v1: Incorporated David Laight's comment
> >  	- Single usage of ffs()
> >
> >  Changes for v2: Incorporated David Laight's comment
> >  	- Changed type of dev_num to unsigned
> >
> >  drivers/ata/sata_fsl.c |    6 ++++--
> >  1 files changed, 4 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/ata/sata_fsl.c b/drivers/ata/sata_fsl.c index
> > b0214d0..895771c 100644
> > --- a/drivers/ata/sata_fsl.c
> > +++ b/drivers/ata/sata_fsl.c
> > @@ -1040,12 +1040,14 @@ 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) {
> > +				link = &ap->pmp_link[dev_num];
> >  				ehi = &link->eh_info;
> >  				qc = ata_qc_from_tag(ap, link->active_tag);
> >  				/*
> 
>

Patch

diff --git a/drivers/ata/sata_fsl.c b/drivers/ata/sata_fsl.c
index b0214d0..895771c 100644
--- a/drivers/ata/sata_fsl.c
+++ b/drivers/ata/sata_fsl.c
@@ -1040,12 +1040,14 @@  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) {
+				link = &ap->pmp_link[dev_num];
 				ehi = &link->eh_info;
 				qc = ata_qc_from_tag(ap, link->active_tag);
 				/*