[U-Boot] [PATCH v2 16/16] sf: Add Flag status register polling support
Simon Glass
sjg at chromium.org
Sat Jun 8 16:32:47 CEST 2013
Hi Jagan,
On Sat, Jun 8, 2013 at 1:32 AM, Jagan Teki <jagannadh.teki at gmail.com> wrote:
> 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.
>
This is not the right patch, but in one of them you remove
spi_flash_cmd_poll_bit(),
so that it no longer works the same way. You will get lots of individual
SPI transactions on the bus instead of a single one that reads the status
byte continuously.
Do we need to change this?
Regards,
Simon
>
> --
> 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
> >
>
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