From: stefan.xk.nilsson@stericsson•com (Stefan Nilsson XK)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH 1/4] mmc: mmci: Bugfix in pio read for small packets
Date: Fri, 14 Oct 2011 09:38:05 +0200 [thread overview]
Message-ID: <4E97E6DD.4030605@stericsson.com> (raw)
In-Reply-To: <20111007191128.GA25689@n2100.arm.linux.org.uk>
On 10/07/2011 09:11 PM, Russell King - ARM Linux wrote:
> But first, you need to fix your code so you're only reading 32-bit
> quantities from the FIFO register.
Hi Russel, what to you think of doing it this way instead:
/*
* SDIO especially may want to send something that is
* not divisible by 4 (as opposed to card sectors
* etc), and the FIFO only accept full 32-bit reads.
*/
if (count < 4) {
unsigned char buf[4];
readsl(base + MMCIFIFO, buf, 1);
memcpy(ptr, buf, count);
}
else
readsl(base + MMCIFIFO, ptr, count >> 2);
This makes sure we only access the FIFO in a 32 bit way, and the only
overhead for the "standard" case (count >= 4) is the "if" clause. I have
verified this to work with our WLAN driver.
Best Regards
Stefan Nilsson
next prev parent reply other threads:[~2011-10-14 7:38 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-09-27 7:46 [PATCH 1/4] mmc: mmci: Bugfix in pio read for small packets Ulf Hansson
2011-10-01 16:09 ` Russell King - ARM Linux
2011-10-03 7:08 ` Stefan Nilsson XK
2011-10-07 13:38 ` Ulf Hansson
2011-10-07 19:11 ` Russell King - ARM Linux
2011-10-14 7:38 ` Stefan Nilsson XK [this message]
2011-10-07 13:45 ` Ulf Hansson
2011-10-08 9:10 ` Russell King - ARM Linux
2011-10-09 6:59 ` Linus Walleij
2011-10-10 8:23 ` Ulf Hansson
2011-10-13 15:48 ` Russell King - ARM Linux
2011-10-14 8:07 ` Ulf Hansson
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