[U-Boot] [PATCH 3/4] sf: Add configuration register writing

[Simon Glass]

Hi Jagan,

On Wed, Dec 12, 2012 at 8:21 AM, Jagan Teki <jagannadh.teki at gmail.com> wrote:
> Hi Simon,
>
> On Wed, Dec 12, 2012 at 8:53 PM, Simon Glass <sjg at chromium.org> wrote:
>> Hi Jagan,
>>
>> On Wed, Dec 12, 2012 at 7:20 AM, Jagan Teki <jagannadh.teki at gmail.com> wrote:
>>> Hi Simon,
>>>
>>> On Wed, Dec 12, 2012 at 12:05 PM, Simon Glass <sjg at chromium.org> wrote:
>>>> Hi,
>>>>
>>>> On Mon, Dec 10, 2012 at 6:42 AM, Jagannadha Sutradharudu Teki
>>>> <jagannadh.teki at gmail.com> wrote:
>>>>> This patch provides support to program a flash config register.
>>>>>
>>>>> Configuration register contains the control bits used to configure
>>>>> the different configurations and security features of a device.
>>>>>
>>>>> User need to set these bits through spi_flash_cmd_write_config()
>>>>> based on their usage.
>>>>>
>>>>> Signed-off-by: Jagannadha Sutradharudu Teki <jagannadh.teki at gmail.com>
>>>>> ---
>>>>>  drivers/mtd/spi/spi_flash.c          |   27 +++++++++++++++++++++++++++
>>>>>  drivers/mtd/spi/spi_flash_internal.h |    3 +++
>>>>>  2 files changed, 30 insertions(+), 0 deletions(-)
>>>>>
>>>>> diff --git a/drivers/mtd/spi/spi_flash.c b/drivers/mtd/spi/spi_flash.c
>>>>> index 800ed8b..a8f0af0 100644
>>>>> --- a/drivers/mtd/spi/spi_flash.c
>>>>> +++ b/drivers/mtd/spi/spi_flash.c
>>>>> @@ -274,6 +274,33 @@ int spi_flash_cmd_write_status(struct spi_flash *flash, u8 sr)
>>>>>         return 0;
>>>>>  }
>>>>>
>>>>> +int spi_flash_cmd_write_config(struct spi_flash *flash, u16 cr)
>>>>> +{
>>>>> +       u8 cmd;
>>>>> +       int ret;
>>>>> +
>>>>> +       ret = spi_flash_cmd_write_enable(flash);
>>>>> +       if (ret < 0) {
>>>>> +               debug("SF: enabling write failed\n");
>>>>> +               return ret;
>>>>> +       }
>>>>> +
>>>>> +       cmd = CMD_WRITE_STATUS;
>>>>> +       ret = spi_flash_cmd_write(flash->spi, &cmd, 1, &cr, 2);
>>>>
>>>> Does this assume a particular endianness? Perhaps should put the
>>>> values into a byte array instead?
>>>
>>> Yes it follows the endianness.
>>
>> My concern was more that u16 is being used to send two bytes. How about:
>>
>> u8 data[2];
>
> Means I need to send status on data[1] and config on data[0].?
>
>>
>> put_unaligned_le16(cr, data)
>
> I couldn't understand this, may be for endianness.?

Yes that's right. Just checking that your code will work correctly on
a big-endian machine. Will it? It is normally not a good idea to cast
a short into a char[2].

Regards,
Simon

>
> Thanks,
> Jagan.
>
>>
>>>
>>> On my QPP patch,
>>> ret = spi_flash_cmd_write_config(flash, 0x0200);
>>>
>>> where 02 is config and 00 is status register
>>> WRR have CMD+status+config => for CMD+16 data format.
>>>
>>> Let me know if you need any info.
>>
>> OK.
>>
>> Regards,
>> Simon
>>
>>>
>>> Thanks,
>>> Jagan.
>>>
>>>>
>>>>> +       if (ret) {
>>>>> +               debug("SF: fail to write config register\n");
>>>>> +               return ret;
>>>>> +       }
>>>>> +
>>>>> +       ret = spi_flash_cmd_wait_ready(flash, SPI_FLASH_PROG_TIMEOUT);
>>>>> +       if (ret < 0) {
>>>>> +               debug("SF: write config register timed out\n");
>>>>> +               return ret;
>>>>> +       }
>>>>> +
>>>>> +       return 0;
>>>>> +}
>>>>> +
>>>>>  /*
>>>>>   * The following table holds all device probe functions
>>>>>   *
>>>>> diff --git a/drivers/mtd/spi/spi_flash_internal.h b/drivers/mtd/spi/spi_flash_internal.h
>>>>> index 141cfa8..9287778 100644
>>>>> --- a/drivers/mtd/spi/spi_flash_internal.h
>>>>> +++ b/drivers/mtd/spi/spi_flash_internal.h
>>>>> @@ -77,6 +77,9 @@ static inline int spi_flash_cmd_write_disable(struct spi_flash *flash)
>>>>>  /* Program the status register. */
>>>>>  int spi_flash_cmd_write_status(struct spi_flash *flash, u8 sr);
>>>>>
>>>>> +/* Program the config register. */
>>>>> +int spi_flash_cmd_write_config(struct spi_flash *flash, u16 cr);
>>>>> +
>>>>>  /*
>>>>>   * Same as spi_flash_cmd_read() except it also claims/releases the SPI
>>>>>   * bus. Used as common part of the ->read() operation.
>>>>> --
>>>>> 1.7.0.4
>>>>>
>>>>> _______________________________________________
>>>>> U-Boot mailing list
>>>>> U-Boot at lists.denx.de
>>>>> http://lists.denx.de/mailman/listinfo/u-boot
>>>>
>>>> Regards,
>>>> Simon