Patchwork [U-Boot] ARM: fix write*() I/O accessors

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Submitter Wolfgang Denk
Date Feb. 11, 2011, 10:25 p.m.
Message ID <1297463148-6612-1-git-send-email-wd@denx.de>
Download mbox | patch
Permalink /patch/82841/
State Accepted
Commit 495df3bad9f250a36470cce15f14c36c616172b6
Delegated to: Albert ARIBAUD
Headers show

Comments

Wolfgang Denk - Feb. 11, 2011, 10:25 p.m.
Commit 3c0659b "ARM: Avoid compiler optimization for readb, writeb
and friends." introduced I/O accessors with memory barriers.
Unfortunately the new write*() accessors introduced a bug:

The problem is that the argument "v" gets evaluated twice.  This
breaks code like used here (from "drivers/net/dnet.c"):

	for (i = 0; i < wrsz; i++)
		writel(*bufp++, &dnet->regs->TX_DATA_FIFO);

Use auxiliary variables to avoid such problems.

Signed-off-by: Wolfgang Denk <wd@denx.de>
Cc: Albert Aribaud <albert.aribaud@free.fr>
Cc: Alexander Holler <holler@ahsoftware.de>
Cc: Dirk Behme <dirk.behme@googlemail.com>
---

This patch fixes a pretty nasty problem.  Everybody who has
experienced strange failures on ARM lately should apply it ASAP and
re-test.  As far as I can tell at least the following drivers are
affected:

drivers/net/dnet.c:		writel(*bufp++, &dnet->regs->TX_DATA_FIFO);
drivers/usb/musb/musb_core.c:	writeb(*data++, &musbr->fifox[ep]);
drivers/mmc/pxa_mmc.c:		writel(*src++, MMC_TXFIFO);
drivers/mmc/mxcmmc.c:		writel(*buf++, &host->base->buffer_access);
drivers/spi/davinci_spi.c:	writel(data1_reg_val | *txp++, &ds->regs->dat1);

Albert, please apply ASAP!


 arch/arm/include/asm/io.h |    6 +++---
 1 files changed, 3 insertions(+), 3 deletions(-)
Albert ARIBAUD - Feb. 11, 2011, 10:31 p.m.
Le 11/02/2011 23:25, Wolfgang Denk a écrit :
> Commit 3c0659b "ARM: Avoid compiler optimization for readb, writeb
> and friends." introduced I/O accessors with memory barriers.
> Unfortunately the new write*() accessors introduced a bug:
>
> The problem is that the argument "v" gets evaluated twice.  This
> breaks code like used here (from "drivers/net/dnet.c"):
>
> 	for (i = 0; i<  wrsz; i++)
> 		writel(*bufp++,&dnet->regs->TX_DATA_FIFO);
>
> Use auxiliary variables to avoid such problems.
>
> Signed-off-by: Wolfgang Denk<wd@denx.de>
> Cc: Albert Aribaud<albert.aribaud@free.fr>
> Cc: Alexander Holler<holler@ahsoftware.de>
> Cc: Dirk Behme<dirk.behme@googlemail.com>
> ---
>
> This patch fixes a pretty nasty problem.  Everybody who has
> experienced strange failures on ARM lately should apply it ASAP and
> re-test.  As far as I can tell at least the following drivers are
> affected:
>
> drivers/net/dnet.c:		writel(*bufp++,&dnet->regs->TX_DATA_FIFO);
> drivers/usb/musb/musb_core.c:	writeb(*data++,&musbr->fifox[ep]);
> drivers/mmc/pxa_mmc.c:		writel(*src++, MMC_TXFIFO);
> drivers/mmc/mxcmmc.c:		writel(*buf++,&host->base->buffer_access);
> drivers/spi/davinci_spi.c:	writel(data1_reg_val | *txp++,&ds->regs->dat1);
>
> Albert, please apply ASAP!

Applied, available on u-boot-arm/master.

Amicalement,
Wolfgang Denk - Feb. 11, 2011, 10:40 p.m.
Dear Albert ARIBAUD,

In message <4D55B8C9.8070605@free.fr> you wrote:
>
> > This patch fixes a pretty nasty problem.  Everybody who has
> > experienced strange failures on ARM lately should apply it ASAP and
> > re-test.  As far as I can tell at least the following drivers are
> > affected:
> >
> > drivers/net/dnet.c:		writel(*bufp++,&dnet->regs->TX_DATA_FIFO);
> > drivers/usb/musb/musb_core.c:	writeb(*data++,&musbr->fifox[ep]);
> > drivers/mmc/pxa_mmc.c:		writel(*src++, MMC_TXFIFO);
> > drivers/mmc/mxcmmc.c:		writel(*buf++,&host->base->buffer_access);
> > drivers/spi/davinci_spi.c:	writel(data1_reg_val | *txp++,&ds->regs->dat1);
> >
> > Albert, please apply ASAP!
> 
> Applied, available on u-boot-arm/master.

Thanks, highly appreciated.

Best regards,

Wolfgang Denk
Alexander Holler - Feb. 11, 2011, 10:51 p.m.
Hello,

Am 11.02.2011 23:25, schrieb Wolfgang Denk:
> +#define writeb(v,c)	({ u8  __v = v; __iowmb(); __arch_putb(__v,c); __v; })
> +#define writew(v,c)	({ u16 __v = v; __iowmb(); __arch_putw(__v,c); __v; })
> +#define writel(v,c)	({ u32 __v = v; __iowmb(); __arch_putl(__v,c); __v; })


Thanks a lot, can I have the do {} while() back? I still don't like such 
macro-making-sense-only constructs. (Just kidding). ;)

Regards,

Alexander

Patch

diff --git a/arch/arm/include/asm/io.h b/arch/arm/include/asm/io.h
index 3886f15..1fbc531 100644
--- a/arch/arm/include/asm/io.h
+++ b/arch/arm/include/asm/io.h
@@ -133,9 +133,9 @@  extern inline void __raw_readsl(unsigned int addr, void *data, int longlen)
 #define __iormb()	dmb()
 #define __iowmb()	dmb()
 
-#define writeb(v,c)	({ __iowmb(); __arch_putb(v,c); v; })
-#define writew(v,c)	({ __iowmb(); __arch_putw(v,c); v; })
-#define writel(v,c)	({ __iowmb(); __arch_putl(v,c); v; })
+#define writeb(v,c)	({ u8  __v = v; __iowmb(); __arch_putb(__v,c); __v; })
+#define writew(v,c)	({ u16 __v = v; __iowmb(); __arch_putw(__v,c); __v; })
+#define writel(v,c)	({ u32 __v = v; __iowmb(); __arch_putl(__v,c); __v; })
 
 #define readb(c)	({ u8  __v = __arch_getb(c); __iormb(); __v; })
 #define readw(c)	({ u16 __v = __arch_getw(c); __iormb(); __v; })