Re: [PATCH] libertas: if_sdio: fix buffer alignment in struct if_sdio_card

[Marek Vasut <marek.vasut@gmail.com>]

Dne Ne 22. srpna 2010 15:22:08 Mike Rapoport napsal(a):
> Marek Vasut wrote:
> > Dne Ne 22. srpna 2010 13:22:40 Mike Rapoport napsal(a):
> >> The commit 886275ce41a9751117367fb387ed171049eb6148 (param: lock
> >> if_sdio's lbs_helper_name and lbs_fw_name against sysfs changes)
> >> introduced new fields into the if_sdio_card structure. It caused
> >> missalignment of the if_sdio_card.buffer field and failure at driver
> >> 
> >> load time:
> >>   ~# modprobe libertas_sdio
> >>   [   62.315124] libertas_sdio: Libertas SDIO driver
> >>   [   62.319976] libertas_sdio: Copyright Pierre Ossman
> >>   [   63.020629] DMA misaligned error with device 48
> >>   [   63.025207] mmci-omap-hs mmci-omap-hs.1: unexpected dma status 800
> >>   [   66.005035] libertas: command 0x0003 timed out
> >>   [   66.009826] libertas: Timeout submitting command 0x0003
> >>   [   66.016296] libertas: PREP_CMD: command 0x0003 failed: -110
> >> 
> >> Adding explicit alignment attribute for the if_sdio_card.buffer field
> >> fixes this problem.
> >> 
> >> Signed-off-by: Mike Rapoport <mike@compulab.co.il>
> >> ---
> >> 
> >>  drivers/net/wireless/libertas/if_sdio.c |    2 +-
> >>  1 files changed, 1 insertions(+), 1 deletions(-)
> >> 
> >> diff --git a/drivers/net/wireless/libertas/if_sdio.c
> >> b/drivers/net/wireless/libertas/if_sdio.c index ba854c7..87b6349 100644
> >> --- a/drivers/net/wireless/libertas/if_sdio.c
> >> +++ b/drivers/net/wireless/libertas/if_sdio.c
> >> @@ -128,7 +128,7 @@ struct if_sdio_card {
> >> 
> >>  	bool			helper_allocated;
> >>  	bool			firmware_allocated;
> >> 
> >> -	u8			buffer[65536];
> >> +	u8			buffer[65536] __attribute__((aligned(4)));
> >> 
> >>  	spinlock_t		lock;
> >>  	struct if_sdio_packet	*packets;
> > 
> > Will this work even on platforms that need some weird DMA destination
> > address alignment ? I might be totally off with this question though ;-)
> 
> I've tested it on PXA and OMAP and it works on both.
> I think that on platforms with weird DMA destination address alignment
> libertas_sdio will fail anyway because of if_sdio_packet alignment.

You're right ... thanks for clearing this.

Acked-by: Marek Vasut <marek.vasut@gmail.com>
> 
> > Cheers
> > --
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