[U-Boot] [PATCH v2 16/16] sf: Add Flag status register polling support

[Jagan Teki]

Hi Simon,

Please let know your comments.

I have changed the logic, but removed spi_flash_cmd_poll_bit() use
poll code on spi_flash_cmd_wait_ready()
as no other call for spi_flash_cmd_poll_bit() this.

And also for read_status the check_status i assigned as 0,earlier it
has direct 0 (w/o check_status variable).

To add the support for flag status on the same code, i define this check_status.
I don't see any coding functionality change for now, compared to before.

--
Thanks,
Jagan.

On Fri, May 31, 2013 at 6:22 PM, Jagannadha Sutradharudu Teki
<jagannadha.sutradharudu-teki at xilinx.com> wrote:
> Flag status register polling is required for micron 512Mb flash
> devices onwards, for performing erase/program operations.
>
> Like polling for WIP(Write-In-Progress) bit in read status register,
> spi_flash_cmd_wait_ready will poll for PEC(Program-Erase-Control)
> bit in flag status register.
>
> Signed-off-by: Jagannadha Sutradharudu Teki <jaganna at xilinx.com>
> ---
> Changes for v2:
>         - none
>
>  drivers/mtd/spi/spi_flash.c          | 15 ++++++++++++---
>  drivers/mtd/spi/spi_flash_internal.h |  3 +++
>  2 files changed, 15 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/mtd/spi/spi_flash.c b/drivers/mtd/spi/spi_flash.c
> index 527423d..8cd2988 100644
> --- a/drivers/mtd/spi/spi_flash.c
> +++ b/drivers/mtd/spi/spi_flash.c
> @@ -195,25 +195,34 @@ int spi_flash_cmd_wait_ready(struct spi_flash *flash, unsigned long timeout)
>         unsigned long timebase;
>         int ret;
>         u8 status;
> +       u8 check_status = 0x0;
>         u8 poll_bit = STATUS_WIP;
>         u8 cmd = CMD_READ_STATUS;
>
> +       if ((flash->idcode0 == 0x20) &&
> +                       (flash->size >= SPI_FLASH_512MB_STMIC)) {
> +               poll_bit = STATUS_PEC;
> +               check_status = poll_bit;
> +               cmd = CMD_FLAG_STATUS;
> +       }
> +
>         timebase = get_timer(0);
>         do {
>                 WATCHDOG_RESET();
>
>                 ret = spi_flash_read_common(flash, &cmd, 1, &status, 1);
>                 if (ret < 0) {
> -                       debug("SF: fail to read read status register\n");
> +                       debug("SF: fail to read %s status register\n",
> +                               cmd == CMD_READ_STATUS ? "read" : "flag");
>                         return ret;
>                 }
>
> -               if ((status & poll_bit) == 0)
> +               if ((status & poll_bit) == check_status)
>                         break;
>
>         } while (get_timer(timebase) < timeout);
>
> -       if ((status & poll_bit) == 0)
> +       if ((status & poll_bit) == check_status)
>                 return 0;
>
>         /* Timed out */
> diff --git a/drivers/mtd/spi/spi_flash_internal.h b/drivers/mtd/spi/spi_flash_internal.h
> index ac4530f..cb7a505 100644
> --- a/drivers/mtd/spi/spi_flash_internal.h
> +++ b/drivers/mtd/spi/spi_flash_internal.h
> @@ -13,6 +13,7 @@
>  #define SPI_FLASH_SECTOR_ERASE_TIMEOUT (10 * CONFIG_SYS_HZ)
>
>  #define SPI_FLASH_16MB_BOUN            0x1000000
> +#define SPI_FLASH_512MB_STMIC          0x4000000
>
>  /* Common commands */
>  #define CMD_READ_ID                    0x9f
> @@ -24,6 +25,7 @@
>  #define CMD_PAGE_PROGRAM               0x02
>  #define CMD_WRITE_DISABLE              0x04
>  #define CMD_READ_STATUS                        0x05
> +#define CMD_FLAG_STATUS                        0x70
>  #define CMD_WRITE_ENABLE               0x06
>  #define CMD_ERASE_4K                   0x20
>  #define CMD_ERASE_32K                  0x52
> @@ -38,6 +40,7 @@
>
>  /* Common status */
>  #define STATUS_WIP                     0x01
> +#define STATUS_PEC                     0x80
>
>  /* Send a single-byte command to the device and read the response */
>  int spi_flash_cmd(struct spi_slave *spi, u8 cmd, void *response, size_t len);
> --
> 1.8.3
>