On Tue, Dec 21, 2010 at 1:35 AM, Dirk Behme <dirk.be...@googlemail.com> wrote:
>
> (Resend with corrected broken example)
>
> On 21.12.2010 08:21, Albert ARIBAUD wrote:
>> Hi Dirk,
>>
>> Le 21/12/2010 08:11, Dirk Behme a écrit :
>>
>>> But the issue with drivers/mtd/nand/omap_gpmc.c (i.e. the additional
>>> ldrb r3, [r3]) is still open? Has anybody tried to replace it with
>>> a nop in the binary to be sure this is the root cause?
>>
>> Can you try and preprocess the C file for both the broken and working
>> cases, then post the preprocessed C extract? Differences at the C level
>> may help understanding differences at the asm level.
>
> gcc version 4.5.1 (Sourcery G++ Lite 2010.09-50)
>
> Work:
> ====
>
> static void omap_nand_hwcontrol(struct mtd_info *mtd, int32_t cmd,
> uint32_t ctrl)
> {
> register struct nand_chip *this = mtd->priv;
> ...
> if (cmd != -1)
>
> (*(volatile unsigned char *)(this->IO_ADDR_W) = (cmd));
> }
>
> if (cmd != NAND_CMD_NONE)
> 84: e3710001 cmn r1, #1
> origwriteb(cmd, this->IO_ADDR_W);
> 88: 15933004 ldrne r3, [r3, #4]
> 8c: 120110ff andne r1, r1, #255 ; 0xff
> 90: 15c31000 strbne r1, [r3]
> 94: e12fff1e bx lr
> ...
>
>
> Broken:
> ======
>
> static void omap_nand_hwcontrol(struct mtd_info *mtd, int32_t cmd,
> uint32_t ctrl)
> {
> register struct nand_chip *this = mtd->priv;
>
> ...
>
> if (cmd != -1)
> ({ __asm__ __volatile__ ("" : : : "memory"); (*(volatile unsigned
> char *)(this->IO_ADDR_W) = (cmd)); });
> }
>
> if (cmd != NAND_CMD_NONE)
> 84: e3710001 cmn r1, #1
> 88: 012fff1e bxeq lr
> writeb(cmd, this->IO_ADDR_W);
> 8c: e5933004 ldr r3, [r3, #4]
> 90: e20110ff and r1, r1, #255 ; 0xff
> 94: e5c31000 strb r1, [r3]
> 98: e5d33000 ldrb r3, [r3]
> 9c: e12fff1e bx lr
>
>
> The issue seems to be the additional 'ldrb r3, [r3]' added by the
> compiler in the broken version.
>
And I at your suggestion tried modifying the binary changing the extra
ldrb to a nop and it works.
_______________________________________________
U-Boot mailing list
U-Boot@lists.denx.de
http://lists.denx.de/mailman/listinfo/u-boot
