[U-Boot] [PATCH 02/10] drivers: spi: add config to consider command bytes when writting to flash

Álvaro Fernández Rojas
2017-05-20T08:06:06Z

Hi Simon,

El 20/05/2017 a las 4:29, Simon Glass escribió:
> Hi Alvaro,
>
> On 18 May 2017 at 13:29, Álvaro Fernández Rojas <noltari@gmail.com> wrote:
>> Command bytes are part of the written bytes and they should be taken into
>> account when sending a spi transfer.
>>
>> Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
>> ---
>> drivers/mtd/spi/spi_flash.c | 2 +-
>> drivers/spi/Kconfig | 3 +++
>> include/spi.h | 8 +++++++-
>> 3 files changed, 11 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/mtd/spi/spi_flash.c b/drivers/mtd/spi/spi_flash.c
>> index e44c10f..748cc32 100644
>> --- a/drivers/mtd/spi/spi_flash.c
>> +++ b/drivers/mtd/spi/spi_flash.c
>> @@ -380,7 +380,7 @@ int spi_flash_cmd_write_ops(struct spi_flash *flash, u32 offset,
>>
>> if (spi->max_write_size)
>> chunk_len = min(chunk_len,
>> - (size_t)spi->max_write_size);
>> + spi_max_write(spi, sizeof(cmd)));
>>
>> spi_flash_addr(write_addr, cmd);
>>
>> diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
>> index f3f7dbe..a00d401 100644
>> --- a/drivers/spi/Kconfig
>> +++ b/drivers/spi/Kconfig
>> @@ -13,6 +13,9 @@ config DM_SPI
>> typically use driver-private data instead of extending the
>> spi_slave structure.
>>
>> +config SPI_MAX_WRITE_CMD_BYTES
>> + bool "Include command bytes when determining max write size"
>
> Do you really need this, or can you just always do this? If you need
> it, please add detailed help.
Actually we don't need this at all and we could do it always from a BCM63xx point of view, but there are drivers that are hacking this at a lower level, like the ich one:
https://github.com/Noltari/u-boot/blob/master/drivers/spi/ich.c#L355

In my opinion this is wrong, but I added that new kconfig because I didn't want to break other SPI drivers...

Maybe I should reverse it and make this the default, adding a kconfig option option which doesn't include command bytes for those drivers (fsl_qspi also uses max_write_size, but it's quite complex and didn't check if it would break it...).

>
>> +
>> if DM_SPI
>>
>> config ALTERA_SPI
>> diff --git a/include/spi.h b/include/spi.h
>> index 75a994c..310fa4d 100644
>> --- a/include/spi.h
>> +++ b/include/spi.h
>> @@ -63,6 +63,12 @@ struct dm_spi_slave_platdata {
>>
>> #endif /* CONFIG_DM_SPI */
>>
>> +#ifdef CONFIG_SPI_MAX_WRITE_CMD_BYTES
>> +#define spi_max_write(spi, len) (spi->max_write_size - len)
>> +#else
>> +#define spi_max_write(spi, len) (spi->max_write_size)
>> +#endif
>> +
>> /**
>> * struct spi_slave - Representation of a SPI slave
>> *
>> @@ -89,7 +95,7 @@ struct dm_spi_slave_platdata {
>> * @max_read_size: If non-zero, the maximum number of bytes which can
>> * be read at once.
>> * @max_write_size: If non-zero, the maximum number of bytes which can
>> - * be written at once, excluding command bytes.
>> + * be written at once.
>> * @memory_map: Address of read-only SPI flash access.
>> * @flags: Indication of SPI flags.
>> */
>> --
>> 2.1.4
>>
>
> Regards,
> Simon
>

Regards,
Álvaro.