[U-Boot] [PATCH v6 08/12] sf: Discover read dummy_cycles

[Jagan Teki]

On Mon, Jan 6, 2014 at 3:51 PM, Sourav Poddar <sourav.poddar at ti.com> wrote:
> On Monday 06 January 2014 03:48 PM, Jagan Teki wrote:
>>
>> Hi Sourav,
>>
>> On Mon, Jan 6, 2014 at 12:34 PM, Sourav Poddar<sourav.poddar at ti.com>
>> wrote:
>>>
>>> On Saturday 04 January 2014 08:34 PM, Jagannadha Sutradharudu Teki wrote:
>>>>
>>>> Discovered the read dummy_cycles based on the configured
>>>> read command.
>>>>
>>>> Signed-off-by: Jagannadha Sutradharudu Teki<jaganna at xilinx.com>
>>>> ---
>>>>    drivers/mtd/spi/sf_internal.h |  2 ++
>>>>    drivers/mtd/spi/sf_ops.c      | 10 ++++++----
>>>>    drivers/mtd/spi/sf_probe.c    | 12 ++++++++++++
>>>>    include/spi_flash.h           |  2 ++
>>>>    4 files changed, 22 insertions(+), 4 deletions(-)
>>>>
>>>> diff --git a/drivers/mtd/spi/sf_internal.h
>>>> b/drivers/mtd/spi/sf_internal.h
>>>> index 7be0292..a9f5a81 100644
>>>> --- a/drivers/mtd/spi/sf_internal.h
>>>> +++ b/drivers/mtd/spi/sf_internal.h
>>>> @@ -10,6 +10,8 @@
>>>>    #ifndef _SF_INTERNAL_H_
>>>>    #define _SF_INTERNAL_H_
>>>>
>>>> +#define SPI_FLASH_3B_ADDR_LEN          3
>>>> +#define SPI_FLASH_CMD_LEN              (1 + SPI_FLASH_3B_ADDR_LEN)
>>>>    #define SPI_FLASH_16MB_BOUN           0x1000000
>>>>
>>>>    /* CFI Manufacture ID's */
>>>> diff --git a/drivers/mtd/spi/sf_ops.c b/drivers/mtd/spi/sf_ops.c
>>>> index 827f719..dda75b1 100644
>>>> --- a/drivers/mtd/spi/sf_ops.c
>>>> +++ b/drivers/mtd/spi/sf_ops.c
>>>> @@ -9,6 +9,7 @@
>>>>     */
>>>>
>>>>    #include<common.h>
>>>> +#include<malloc.h>
>>>>    #include<spi.h>
>>>>    #include<spi_flash.h>
>>>>    #include<watchdog.h>
>>>> @@ -216,7 +217,7 @@ int spi_flash_write_common(struct spi_flash *flash,
>>>> const u8 *cmd,
>>>>    int spi_flash_cmd_erase_ops(struct spi_flash *flash, u32 offset,
>>>> size_t
>>>> len)
>>>>    {
>>>>          u32 erase_size;
>>>> -       u8 cmd[4];
>>>> +       u8 cmd[SPI_FLASH_CMD_LEN];
>>>>          int ret = -1;
>>>>
>>>>          erase_size = flash->erase_size;
>>>> @@ -255,7 +256,7 @@ int spi_flash_cmd_write_ops(struct spi_flash *flash,
>>>> u32 offset,
>>>>    {
>>>>          unsigned long byte_addr, page_size;
>>>>          size_t chunk_len, actual;
>>>> -       u8 cmd[4];
>>>> +       u8 cmd[SPI_FLASH_CMD_LEN];
>>>>          int ret = -1;
>>>>
>>>>          page_size = flash->page_size;
>>>> @@ -317,7 +318,7 @@ int spi_flash_read_common(struct spi_flash *flash,
>>>> const u8 *cmd,
>>>>    int spi_flash_cmd_read_ops(struct spi_flash *flash, u32 offset,
>>>>                  size_t len, void *data)
>>>>    {
>>>> -       u8 cmd[5], bank_sel = 0;
>>>> +       u8 *cmd, bank_sel = 0;
>>>>          u32 remain_len, read_len;
>>>>          int ret = -1;
>>>>
>>>> @@ -335,8 +336,9 @@ int spi_flash_cmd_read_ops(struct spi_flash *flash,
>>>> u32 offset,
>>>>                  return 0;
>>>>          }
>>>>
>>>> +       cmd = malloc(SPI_FLASH_CMD_LEN + flash->dummy_cycles);
>>>> +       memset(cmd, 0, SPI_FLASH_CMD_LEN + flash->dummy_cycles);
>>>>          cmd[0] = flash->read_cmd;
>>>> -       cmd[4] = 0x00;
>>>>
>>>>          while (len) {
>>>>    #ifdef CONFIG_SPI_FLASH_BAR
>>>> diff --git a/drivers/mtd/spi/sf_probe.c b/drivers/mtd/spi/sf_probe.c
>>>> index a049e72..b070adc 100644
>>>> --- a/drivers/mtd/spi/sf_probe.c
>>>> +++ b/drivers/mtd/spi/sf_probe.c
>>>> @@ -140,6 +140,18 @@ static struct spi_flash
>>>> *spi_flash_validate_params(struct spi_slave *spi,
>>>>                  }
>>>>          }
>>>>
>>>> +       /* Read dummy cycles */
>>>> +       switch (flash->read_cmd) {
>>>> +       case CMD_READ_QUAD_IO_FAST:
>>>> +               flash->dummy_cycles = 2;
>>>> +               break;
>>>> +       case CMD_READ_ARRAY_SLOW:
>>>> +               flash->dummy_cycles = 0;
>>>> +               break;
>>>> +       default:
>>>> +               flash->dummy_cycles = 1;
>>>> +       }
>>>> +
>>>
>>> what about dummy cycles for dual i/o(0xbb), it has 4 clock bit dummy
>>> cycles(macronix), so
>>> by your code you keep it to 1(8 bit) dummy cycle. ?
>>
>> Yes- Actually i miss used the names here.
>> These are dummy_byte_count
>>
>> Ex: Except fast reads (array, dual and quad fast)
>> dummy_byte_count = dummy_cycles * no.of lines
>> dual i/o (4 dummy_cycles) - 4 * 2 = 1 dummy_byte
>> quad i/o (4 dummy_cycles) - 4 * 4 = 2 dummy_byte
>>
> is this calculation documented in any of the flash sheet?

I haven't see the exact calculation but ie. how the I/O operation usually works.
quad read - cmd, 3byte_inst, 1 dummy_byte(8 dummy_cycles) goes on
single line and data goes in 4 lines
quad i/o - except cmd(1 lines) remaining goes in 4 lines.

>
>> fast, dual and quad fast have 8 dummy_cycles means 1 byte dummy the
>> reason why I am not including
>> no.of lines here is irrespective of fast(1 line), dual(2 lines) and
>> quad(4 lines) only data can travel among the difference lines
>> but the cmd,inst, dummy can travel only on single line. this can be
>> opposite in i/o commands.
>>
>> Hope you understand - I just said based on my knowledge.
>> I will change the dummy_cycles into dummy_bytes - nevertheless everything
>> same.
>>
>

-- 
Thanks,
Jagan.