[U-Boot] [RFC PATCH v1 1/6] mtd: nand: pxa3xx_nand: Increase initial buffer size

[Chris Packham]

On Fri, Oct 21, 2016 at 1:58 AM, Ezequiel Garcia
<ezequiel at vanguardiasur.com.ar> wrote:
> On 20 October 2016 at 01:31, Chris Packham <judge.packham at gmail.com> wrote:
>> The initial buffer is used for the initial commands used to detect
>> a flash device (STATUS, READID and PARAM).
>>
>> ONFI param page is 256 bytes, and there are three redundant copies
>> to be read. JEDEC param page is 512 bytes, and there are also three
>> redundant copies to be read. Hence this buffer should be at least
>> 512 x 3. This commits rounds the buffer size to 2048.
>>
>
> Hey Chris,
>
> So you are basically picking the commit and commit log from Linux:
>
> http://lists.infradead.org/pipermail/linux-mtd/2015-August/060721.html
>
> Shouldn't you mention that somewhere?

Indeed. I mentioned it here
http://lists.denx.de/pipermail/u-boot/2016-October/270605.html and
that was the intent of the Cc line below.

I should probably set the From: line to the original author and call
out the Linux commit sha1. I wasn't sure of the usual u-boot practice,
I could equally squash these all together and say "sync with linux".

>
>> Cc: Ezequiel Garcia <ezequiel at vanguardiasur.com.ar>
>> Signed-off-by: Chris Packham <judge.packham at gmail.com>
>> ---
>>
>>  drivers/mtd/nand/pxa3xx_nand.c | 16 ++++++++++------
>>  1 file changed, 10 insertions(+), 6 deletions(-)
>>
>> diff --git a/drivers/mtd/nand/pxa3xx_nand.c b/drivers/mtd/nand/pxa3xx_nand.c
>> index dfe8966b56b6..ea0a6f3778bd 100644
>> --- a/drivers/mtd/nand/pxa3xx_nand.c
>> +++ b/drivers/mtd/nand/pxa3xx_nand.c
>> @@ -26,10 +26,13 @@
>>
>>  /*
>>   * Define a buffer size for the initial command that detects the flash device:
>> - * STATUS, READID and PARAM. The largest of these is the PARAM command,
>> - * needing 256 bytes.
>> + * STATUS, READID and PARAM.
>> + * ONFI param page is 256 bytes, and there are three redundant copies
>> + * to be read. JEDEC param page is 512 bytes, and there are also three
>> + * redundant copies to be read.
>> + * Hence this buffer should be at least 512 x 3. Let's pick 2048.
>>   */
>> -#define INIT_BUFFER_SIZE       256
>> +#define INIT_BUFFER_SIZE       2048
>>
>>  /* registers and bit definitions */
>>  #define NDCR           (0x00) /* Control register */
>> @@ -838,14 +841,14 @@ static int prepare_set_command(struct pxa3xx_nand_info *info, int command,
>>                 break;
>>
>>         case NAND_CMD_PARAM:
>> -               info->buf_count = 256;
>> +               info->buf_count = INIT_BUFFER_SIZE;
>>                 info->ndcb0 |= NDCB0_CMD_TYPE(0)
>>                                 | NDCB0_ADDR_CYC(1)
>>                                 | NDCB0_LEN_OVRD
>>                                 | command;
>>                 info->ndcb1 = (column & 0xFF);
>> -               info->ndcb3 = 256;
>> -               info->data_size = 256;
>> +               info->ndcb3 = INIT_BUFFER_SIZE;
>> +               info->data_size = INIT_BUFFER_SIZE;
>>                 break;
>>
>>         case NAND_CMD_READID:
>> @@ -1468,6 +1471,7 @@ KEEP_CONFIG:
>>                 host->row_addr_cycles = 3;
>>         else
>>                 host->row_addr_cycles = 2;
>> +
>
> Spurious change. I suggest to drop it.
>

Will do.

>>         return nand_scan_tail(mtd);
>>  }
>>
>> --
>> 2.10.0.479.g7c56b16
>>
>
>
>
> --
> Ezequiel García, VanguardiaSur
> www.vanguardiasur.com.ar