[PATCH] nfit, nd_blk: BLK status register is only 32 bits

[PATCH] nfit, nd_blk: BLK status register is only 32 bits

[Ross Zwisler]

Only read 32 bits for the BLK status register in read_blk_stat().

The format and size of this register is defined in the
"NVDIMM Driver Writer's guide":

http://pmem.io/documents/NVDIMM_Driver_Writers_Guide.pdf

Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Reported-by: Nicholas Moulin <nicholas.w.moulin@linux.intel.com>
---
 drivers/acpi/nfit.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/acpi/nfit.c b/drivers/acpi/nfit.c
index 7c2638f..8689ee1 100644
--- a/drivers/acpi/nfit.c
+++ b/drivers/acpi/nfit.c
@@ -1009,7 +1009,7 @@ static void wmb_blk(struct nfit_blk *nfit_blk)
 		wmb_pmem();
 }
 
-static u64 read_blk_stat(struct nfit_blk *nfit_blk, unsigned int bw)
+static u32 read_blk_stat(struct nfit_blk *nfit_blk, unsigned int bw)
 {
 	struct nfit_blk_mmio *mmio = &nfit_blk->mmio[DCR];
 	u64 offset = nfit_blk->stat_offset + mmio->size * bw;
@@ -1017,7 +1017,7 @@ static u64 read_blk_stat(struct nfit_blk *nfit_blk, unsigned int bw)
 	if (mmio->num_lines)
 		offset = to_interleave_offset(offset, mmio);
 
-	return readq(mmio->base + offset);
+	return readl(mmio->base + offset);
 }
 
 static void write_blk_ctl(struct nfit_blk *nfit_blk, unsigned int bw,
-- 
2.1.0

Re: [PATCH] nfit, nd_blk: BLK status register is only 32 bits

[Jeff Moyer]

Ross Zwisler <ross.zwisler@linux.intel.com> writes:

> Only read 32 bits for the BLK status register in read_blk_stat().
>
> The format and size of this register is defined in the
> "NVDIMM Driver Writer's guide":
>
> http://pmem.io/documents/NVDIMM_Driver_Writers_Guide.pdf
>
> Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
> Reported-by: Nicholas Moulin <nicholas.w.moulin@linux.intel.com>

Looks fine,

Reviewed-by: Jeff Moyer <jmoyer@redhat.com>

However, now that you've drawn attention to that code, I'll note that
there is no checking of the pending or retry bits.  In fact,
ACPI_NFIT_CONTROL_BUFFERED isn't even checked upon loading the tables.
Is this on a todo list somewhere?

Cheers,
Jeff

> ---
>  drivers/acpi/nfit.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/acpi/nfit.c b/drivers/acpi/nfit.c
> index 7c2638f..8689ee1 100644
> --- a/drivers/acpi/nfit.c
> +++ b/drivers/acpi/nfit.c
> @@ -1009,7 +1009,7 @@ static void wmb_blk(struct nfit_blk *nfit_blk)
>  		wmb_pmem();
>  }
>  
> -static u64 read_blk_stat(struct nfit_blk *nfit_blk, unsigned int bw)
> +static u32 read_blk_stat(struct nfit_blk *nfit_blk, unsigned int bw)
>  {
>  	struct nfit_blk_mmio *mmio = &nfit_blk->mmio[DCR];
>  	u64 offset = nfit_blk->stat_offset + mmio->size * bw;
> @@ -1017,7 +1017,7 @@ static u64 read_blk_stat(struct nfit_blk *nfit_blk, unsigned int bw)
>  	if (mmio->num_lines)
>  		offset = to_interleave_offset(offset, mmio);
>  
> -	return readq(mmio->base + offset);
> +	return readl(mmio->base + offset);
>  }
>  
>  static void write_blk_ctl(struct nfit_blk *nfit_blk, unsigned int bw,

Re: [PATCH] nfit, nd_blk: BLK status register is only 32 bits

[Ross Zwisler]

On Mon, Aug 24, 2015 at 01:02:17PM -0400, Jeff Moyer wrote:
> Ross Zwisler <ross.zwisler@linux.intel.com> writes:
> 
> > Only read 32 bits for the BLK status register in read_blk_stat().
> >
> > The format and size of this register is defined in the
> > "NVDIMM Driver Writer's guide":
> >
> > http://pmem.io/documents/NVDIMM_Driver_Writers_Guide.pdf
> >
> > Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
> > Reported-by: Nicholas Moulin <nicholas.w.moulin@linux.intel.com>
> 
> Looks fine,
> 
> Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
> 
> However, now that you've drawn attention to that code, I'll note that
> there is no checking of the pending or retry bits.  In fact,
> ACPI_NFIT_CONTROL_BUFFERED isn't even checked upon loading the tables.
> Is this on a todo list somewhere?

Yep, you're right, we do need to add support for each of these.  I'm planning
on doing it unless someone else gets to it first.