Hi Jagan, On Sat, Jun 8, 2013 at 7:44 AM, Jagan Teki <[email protected]> wrote:
> Hi Simon, > > On Sat, Jun 8, 2013 at 8:02 PM, Simon Glass <[email protected]> wrote: > > Hi Jagan, > > > > On Sat, Jun 8, 2013 at 1:32 AM, Jagan Teki <[email protected]> > 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. > > I couldn't understand you clearly. > > Earlier all erase/write they were calling spi_flash_cmd_wait_ready > with flash, timeout values. > spi_flash_cmd_wait_ready() is intern call to spi_flash_cmd_poll_bit() > with CMD_READ_STATUS and STATUS_WIP. > > In my changes I have removed spi_flash_cmd_poll_bit() as there is no > other caller except spi_flash_cmd_wait_ready() > so all polling stuff on spi_flash_cmd_wait_ready() means, still > erase/program can call spi_flash_cmd_wait_ready() with > flash, timeout and CMD_READ_STATUS and STAUS_WIP were use directly > used on spi_flash_cmd_wait_ready() instead > of passing through spi_flash_cmd_poll_bit(). > > Any wrong here, please comment. > You have changed the implementation of spi_flash_cmd_wait_ready() so that instead of polling for the bit within a single SPI transaction (CS staying asserted) you are now doing multiple transactions. The old code for spi_flash_cmd_wait_ready() ended up with an algorithm like this, when you look inside the nested functions: spi_claim_bus(spi); ret = spi_xfer(spi, cmd_len * 8, cmd, NULL, SPI_XFER_BEGIN); do { ret = spi_xfer(spi, 8, NULL, &status, 0); ... } spi_xfer(spi, 0, NULL, NULL, SPI_XFER_END); spi_release_bus(spi); The new code is: do { spi_claim_bus(spi); ret = spi_xfer(spi, cmd_len * 8, cmd, NULL, SPI_XFER_BEGIN); ret = spi_xfer(spi, data_len * 8, data_out, data_in, SPI_XFER_END); spi_release_bus(spi); ... } while (...) Can you see the difference? The bus clain and SPI_XFER_BEGIN/END is now inside the loop. Is there a reason why this change is needed? Does updating the bank address not work with the old code? It is find to move the spi_flash_cmd_poll_bit() function into spi_flash_cmd_wait_ready() - I am not worried about that. I am only worried about your change of algorithm as above. Regards, Simon > > Thanks, > Jagan. > > > > > Do we need to change this? > > > > > >> > >> > >> -- > >> Thanks, > >> Jagan. > >> > >> On Fri, May 31, 2013 at 6:22 PM, Jagannadha Sutradharudu Teki > >> <[email protected]> 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 <[email protected]> > >> > --- > >> > 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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