On Wed, 2015-02-25 at 12:53 +0800, Axel Lin wrote: > 2015-02-25 2:43 GMT+08:00 Andy Shevchenko <[email protected]>: > > The commit d297933cc7fc (spi: dw: Fix detecting FIFO depth) tries to fix the > > logic of the FIFO detection based on the description on the comments. > > However, > > there is a slight difference between numbers in TX Level and TX FIFO size. > > > > So, by specification the FIFO size would be in a range 2-256 bytes. From TX > > Level prospective it means we can set threshold in the range 0-(FIFO size - > > 1) > > bytes. Hence there are currently two issues: > > a) FIFO size 2 bytes is actually skipped since TX Level is 1 bit and > > could be > > either 0 or 1 byte; > > b) FIFO size is incorrectly decreased by 1 which already done by meaning > > of > > TX Level register. > > > > This patch fixes it eventually right. > > > > Fixes: d297933cc7fc (spi: dw: Fix detecting FIFO depth) > > Cc: Axel Lin <[email protected]> > > Cc: [email protected] > > Signed-off-by: Andy Shevchenko <[email protected]> > > --- > > > > Shame on me I somehow missed this when tested mentioned patch. > > > > drivers/spi/spi-dw.c | 4 ++-- > > 1 file changed, 2 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/spi/spi-dw.c b/drivers/spi/spi-dw.c > > index 0257dd1..ba9773d 100644 > > --- a/drivers/spi/spi-dw.c > > +++ b/drivers/spi/spi-dw.c > > @@ -494,14 +494,14 @@ static void spi_hw_init(struct device *dev, struct > > dw_spi *dws) > > if (!dws->fifo_len) { > > u32 fifo; > > > > - for (fifo = 2; fifo <= 256; fifo++) { > > + for (fifo = 1; fifo <= 256; fifo++) { > > I think the upper bound of the for loop should be 255 (FIFO size - 1) > for (fifo = 1; fifo <= 255; fifo++) { > so if writting 255 to DW_SPI_TXFLTR success, fifo_len is 256. > > no need to test writing 256 to DW_SPI_TXFLTR.
Yes, I even just retested carefully. I will change to < 256 and keep your Reviewed-by tag in v2, hope it's okay. -- Andy Shevchenko <[email protected]> Intel Finland Oy -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
