From: Michael Buesch <mb@bu3sch.de>
To: Martin Fuzzey <mfuzzey@gmail.com>
Subject: Re: [PATCH] SSB: fix 32 bit PCMCIA access.
Date: Fri, 6 Nov 2009 18:10:35 +0100
Cc: linux-wireless@vger.kernel.org
References: <20091106155605.20585.15955.stgit@srv002.fuzzey.net>
In-Reply-To: <20091106155605.20585.15955.stgit@srv002.fuzzey.net>
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On Friday 06 November 2009 16:56:05 Martin Fuzzey wrote:
> The scan function was using 32 bit access which does not
> work on 16bit CF cards.
> 
> This patch corrects this by doing two 16 bit reads like
> ssb_pcmcia_read32 already does (unfortunately we don't
> have a struct ssb_device to use that directly).
> 
> Signed-off-by: Martin Fuzzey <mfuzzey@gmail.com>
> 
> ---
> 
>  drivers/ssb/scan.c |    9 ++++++++-
>  1 files changed, 8 insertions(+), 1 deletions(-)
> 
> diff --git a/drivers/ssb/scan.c b/drivers/ssb/scan.c
> index b74212d..6721fa8 100644
> --- a/drivers/ssb/scan.c
> +++ b/drivers/ssb/scan.c
> @@ -162,6 +162,9 @@ static u8 chipid_to_nrcores(u16 chipid)
>  static u32 scan_read32(struct ssb_bus *bus, u8 current_coreidx,
>  		       u16 offset)
>  {
> +	unsigned long flags;
> +	u32 lo, hi;
> +
>  	switch (bus->bustype) {
>  	case SSB_BUSTYPE_SSB:
>  		offset += current_coreidx * SSB_CORE_SIZE;
> @@ -174,7 +177,11 @@ static u32 scan_read32(struct ssb_bus *bus, u8 current_coreidx,
>  			offset -= 0x800;
>  		} else
>  			ssb_pcmcia_switch_segment(bus, 0);
> -		break;
> +		spin_lock_irqsave(&bus->bar_lock, flags);
> +		lo = readw(bus->mmio + offset);
> +		hi = readw(bus->mmio + offset + 2);
> +		spin_unlock_irqrestore(&bus->bar_lock, flags);
> +		return lo | (hi << 16);
>  	case SSB_BUSTYPE_SDIO:
>  		offset += current_coreidx * SSB_CORE_SIZE;
>  		return ssb_sdio_scan_read32(bus, offset);

Thanks for spotting this. This really looks like a bug.
I'll test this patch on my device and remove the unnecessary locks and then resubmit upstream.

Next time, please make sure to Cc maintainers. See the MAINTAINERS file.

-- 
Greetings, Michael.