On Tue, 2015-09-01 at 11:19 +0200, [email protected] wrote: > On Tuesday, September 01, 2015 at 11:13:38 AM, Chin Liang See wrote: > > On Tue, 2015-09-01 at 11:01 +0200, [email protected] wrote: > > > On Tuesday, September 01, 2015 at 10:46:47 AM, Chin Liang See wrote: > > > > Ensuring spi_calibration is run when there is a change of sclk > > > > frequency. This will ensure the qspi flash access works for high > > > > sclk frequency > > > > > > > > Signed-off-by: Chin Liang See <[email protected]> > > > > Cc: Dinh Nguyen <[email protected]> > > > > Cc: Marek Vasut <[email protected]> > > > > Cc: Stefan Roese <[email protected]> > > > > Cc: Vikas Manocha <[email protected]> > > > > Cc: Jagannadh Teki <[email protected]> > > > > Cc: Pavel Machek <[email protected]> > > > > --- > > > > > > > > drivers/spi/cadence_qspi.c | 3 +++ > > > > 1 files changed, 3 insertions(+), 0 deletions(-) > > > > > > > > diff --git a/drivers/spi/cadence_qspi.c b/drivers/spi/cadence_qspi.c > > > > index 34a0f46..512bf2d 100644 > > > > --- a/drivers/spi/cadence_qspi.c > > > > +++ b/drivers/spi/cadence_qspi.c > > > > @@ -128,6 +128,9 @@ static int cadence_spi_set_speed(struct udevice > > > > *bus, uint hz) > > > > > > > > cadence_spi_write_speed(bus, hz); > > > > > > > > + /* to ensure spi_calibration is run when SCLK frequency change > > > > */ > > > > + plat->max_hz = hz; > > > > + > > > > > > This looks like a hack, doesn't this change just subvert the condition > > > below to enforce the calibration ? > > > > Nope. I checked through debugger where plat->max_hz is initialized once > > with the value from device tree. When you use sf probe to change > > frequency, the value is not reflected to plat->max_hz. Hence the > > calibration is not run when frequency change. That lead to the sf probe > > fail when running at 80MHz or higher. Note the priv->qspi_calibrated_hz > > is updated after calibration succeed. > > Isn't the purpose of ->max_hz to reflect the maximum frequency of the bus? > I don't think this should thus ever be updated, in particular not by the > user. I also think that setting ->max_hz once from DT is the correct behavior. >
Oh, in this case, there are more bug in the code. I saw there is mismatch of the usage of this variable. As example, the line "priv->qspi_calibrated_hz = plat->max_hz;" is wrong as it would be always static. Besides that, there is no check against the requested speed not to exceed the max_hz. Let me fix this all again. Thanks Chin Liang > Best regards, > Marek Vasut _______________________________________________ U-Boot mailing list [email protected] http://lists.denx.de/mailman/listinfo/u-boot
