[U-Boot] [PATCH 4/6] S5PC100: onenand driver for SMDKC100 support

[Kyungmin Park]

Hi,

On Sat, Jun 27, 2009 at 2:54 AM, Scott Wood<scottwood at freescale.com> wrote:
> On Thu, Jun 25, 2009 at 05:10:37PM +0900, HeungJun Kim wrote:
>> This patch includes the onenand driver for SMDKC100 Board.
>>
>> Signed-off-by: HeungJun, Kim <riverful.kim at samsung.com>
>>
>> ---
>>
>>  drivers/mtd/onenand/Makefile      |    8 +-
>>  drivers/mtd/onenand/s5p_onenand.c | 2034 +++++++++++++++++++++++++++++++++++++
>>  include/linux/mtd/onenand_regs.h  |    5 +
>>  include/linux/mtd/s5p_onenand.h   |  425 ++++++++
>
> Please try to refactor the existing onenand code to support controller
> variations, rather than duplicating parts of it.
>
> Or if you can find absolutely no common ground (but I hope you can), at
> least change the names so they don't conflict.  Are you planning on
> supporting this in Linux?  What is it going to look like there?
>
> Kyungmin, any thoughts?  Why do we have a specific controller
> implementation in something generically named "onenand_base.c"?  Or is
> this different because of a different type of onenand chip?

Right, I wrote the OneNAND drivers for s3c64xx/s5pc100 but now only
interface part are release at mtd & arm list.

The current status of this patch only *working* version. So I NAKed
this patch. next time Mr Kim will post the new OneNAND drivers

Thank you,
Kyungmin Park

>
> I don't understand OneNAND very well (and google doesn't turn up much but
> marketing), which makes including it under the same custodianship as NAND
> somewhat awkward. :-(
>
>> diff --git a/drivers/mtd/onenand/Makefile b/drivers/mtd/onenand/Makefile
>> index 1d35a57..aad1362 100644
>> --- a/drivers/mtd/onenand/Makefile
>> +++ b/drivers/mtd/onenand/Makefile
>> @@ -25,7 +25,13 @@ include $(TOPDIR)/config.mk
>>
>>  LIB  := $(obj)libonenand.a
>>
>> -COBJS-$(CONFIG_CMD_ONENAND)  := onenand_uboot.o onenand_base.o onenand_bbt.o
>> +COBJS-$(CONFIG_CMD_ONENAND)  := onenand_uboot.o
>> +
>> +ifdef CONFIG_S5PC1XX
>> +COBJS-$(CONFIG_CMD_ONENAND)  += s5p_onenand.o
>> +else
>> +COBJS-$(CONFIG_CMD_ONENAND)  += onenand_base.o onenand_bbt.o
>> +endif
>
> Why no bbt?

This driver checks the bad block at runtime at every access. :)

>
>> +/**
>> + * onenand_read_burst
>> + *
>> + * 16 Burst read: performance is improved up to 40%.
>> + */
>> +static void onenand_read_burst(void *dest, const void *src, size_t len)
>> +{
>> +     int count;
>> +
>> +     if (len % 16 != 0)
>> +             return;
>> +
>> +     count = len / 16;
>> +
>> +     __asm__ __volatile__(
>> +             "       stmdb   r13!, {r0-r3,r9-r12}\n"
>> +             "       mov     r2, %0\n"
>> +             "1:\n"
>> +             "       ldmia   r1, {r9-r12}\n"
>> +             "       stmia   r0!, {r9-r12}\n"
>> +             "       subs    r2, r2, #0x1\n"
>> +             "       bne     1b\n"
>> +             "       ldmia   r13!, {r0-r3,r9-r12}\n"::"r" (count));
>> +}
>
> What is this doing that we couldn't generically make memcpy do?

Even though It looks some strange. it has some performance gain. but
not general.

>
> -Scott
> _______________________________________________
> U-Boot mailing list
> U-Boot at lists.denx.de
> http://lists.denx.de/mailman/listinfo/u-boot
>