[U-Boot] U-boot: Erase/read/write issue with S25fl256S flash device

[Jagan Teki]

On 14-06-2013 20:03, Sourav Poddar wrote:
>
> Hi,
>
> On Wednesday 12 June 2013 01:00 PM, Sourav Poddar wrote:
>> Hi,
>>
>> I am working on qspi flash device S25FL256S at u-boot level. I am
>> trying to
>> make use of the existing spi_flash.c framework available at u-boot for
>> erasing/reading/writing
>> into the flash device.
>>
>> There are several issues(mentioned below), which I faced while using
>> S25FL256s flash device
>> with my dra7xx board which has a qspi controller to which the above
>> mentioned flash device is attached.
>>
>> 1. Erase (spi_flash_cmd_erase)
>>
>> Issuing a command something like this..
>>
>> sf erase 0x0 0x50000
>>  - erases only first 0x20000 bytes of flash device, anything above
>> that is not erase. I need to
>>    issue separate commands after 0x20000 for every 0x10000 bytes.
>>
>> Am i missing anything here?
>>
>> 2. read
>>
>> sf read 81000000 0 0x10000
>>
>> Read is not happening properly. The last few byte along the 4k
>> boundary always shows zero.
>> Above 4k bytes, read is not happening.
>>
>> For ex:
>>  DRA752 EVM # md 81000f00
>> 81000f00: ffffffff ffffffff ffffffff ffffffff    ................
>> 81000f10: ffffffff ffffffff ffffffff ffffffff    ................
>> 81000f20: ffffffff ffffffff ffffffff ffffffff    ................
>> 81000f30: ffffffff ffffffff ffffffff ffffffff    ................
>> 81000f40: ffffffff ffffffff ffffffff ffffffff    ................
>> 81000f50: ffffffff ffffffff ffffffff ffffffff    ................
>> 81000f60: ffffffff ffffffff ffffffff ffffffff    ................
>> 81000f70: ffffffff ffffffff ffffffff ffffffff    ................
>> 81000f80: ffffffff ffffffff ffffffff ffffffff    ................
>> 81000f90: ffffffff ffffffff ffffffff ffffffff    ................
>> 81000fa0: ffffffff ffffffff ffffffff ffffffff    ................
>> 81000fb0: ffffffff ffffffff ffffffff ffffffff    ................
>> 81000fc0: ffffffff ffffffff ffffffff ffffffff    ................
>> 81000fd0: ffffffff ffffffff ffffffff ffffffff    ................
>> 81000fe0: ffffffff ffffffff ffffffff ffffffff    ................
>> 81000ff0: ffffffff ffffffff 00ffffff 00000000    ................
>>
>> In this dump, if you see 81000ff0 the last column shows 000000 which is
>> not expected. and it happens along every 4k bytes.
>>
>>
>> So, to get rid of the above issue, I switched to page read with the
>> below patch[1],
>> which is giving me the correct result.
>> [1]:
>> @@ -147,17 +153,40 @@ int spi_flash_read_common(struct spi_flash
>> *flash, const u8 *cmd,
>>  int spi_flash_cmd_read_fast(struct spi_flash *flash, u32 offset,
>>                 size_t len, void *data)
>>  {
>> -       u8 cmd[5];
>> +       unsigned long page_addr, byte_addr, page_size;
>> +       size_t chunk_len, actual;
>> +       int ret = 0;
>> +       u8 cmd[4];
>>
>>         /* Handle memory-mapped SPI */
>>         if (flash->memory_map)
>>                 memcpy(data, flash->memory_map + offset, len);
>> +       page_size = flash->page_size;
>> +       page_addr = offset / page_size;
>> +       byte_addr = offset % page_size;
>> +
>> +       cmd[0] = CMD_READ_ARRAY_SLOW;
>> +       for (actual = 0; actual < len; actual += chunk_len) {
>> +               chunk_len = min(len - actual, page_size - byte_addr);
>> +
>> +               cmd[1] = page_addr >> 8;
>> +               cmd[2] = page_addr;
>> +               cmd[3] = byte_addr;
>> +
>> +               ret = spi_flash_read_common(flash, cmd, sizeof(cmd),
>> data + actual, chunk_len);
>> +               if (ret < 0) {
>> +                       debug("SF: read failed");
>> +                       break;
>> +               }
>>
>> -       cmd[0] = CMD_READ_ARRAY_FAST;
>> -       spi_flash_addr(offset, cmd);
>> -       cmd[4] = 0x00;
>> +               byte_addr += chunk_len;
>> +               if (byte_addr == page_size) {
>> +                       page_addr++;
>> +                       byte_addr = 0;
>> +               }
>> +       }
>>
>> -       return spi_flash_read_common(flash, cmd, sizeof(cmd), data, len);
>> +       return ret;
>>  }
>>
>> Any idea about this?
>>
>> 3.  write (spi_flash_cmd_write_multi)
>>   write not happening properly.
>>
>> observations: only able to write single page, anything after a page is
>> not getting
>>         written.
>> Workaround:
>> I did a write disable latch at the end of every write cycle(page
>> program) and enable it
>> again for the next loop. With this, I see I get rid of the above issue.
>>
>>  @@ -117,6 +117,12 @@ int spi_flash_cmd_write_multi(struct spi_flash
>> *flash, u32 offset,
>>                 if (ret)
>>                         break;
>>
>> +               ret = spi_flash_cmd_write_disable(flash);
>> +               if (ret < 0) {
>> +                       printf("SF: disabling write failed\n");
>> +                       break;
>> +               }
>> +
>>
>>
>> Have anyone seen the above mentioned issues regarding
>> read/write/erase? OR is there any
>> configurations that I might be missing ?
>>
> Any Input on this?

Please wait, I am pushing some changes tonight or so.

We will continue this thread, after testing your part with these new 
changes.

I will intimate you once the push done.

--
Thanks,
Jagan.