Hi Ashok
On 1/20/21 9:28 PM, Brandon Maier wrote:
If zynqmp_qspi_set_speed() is called multiple times with the same speed, then on the second call it will skip recalculating the baud_rate_val as it assumes the speed is already configured correctly. But it will still write the baud_rate_val to the configuration register and call zynqmp_gqspi_set_tapdelay(). Because it skipped recalculating the baud_rate_val, it will use the initial value of 0 . This causes the driver to run at maximum speed which for many spi flashes is too fast and causes data corruption.
Instead only write out a new baud_rate_val if we have calculated the correct baud_rate_val.
This opens up another issue with the "if (speed == 0)", we don't save off the new plat->speed_hz value when setting the baud rate on the speed=0 path. Instead mimic what the Linux zynqmp gqspi driver does, and have speed==0 just use the same calculation as a normal speed. That will cause the baud_rate_val to use the slowest speed possible, which is the safest option.
Signed-off-by: Brandon Maier brandon.maier@rockwellcollins.com CC: jagan@amarulasolutions.com CC: michal.simek@xilinx.com CC: Ashok Reddy Soma ashokred@xilinx.com
drivers/spi/zynqmp_gqspi.c | 23 +++++++++++------------ 1 file changed, 11 insertions(+), 12 deletions(-)
diff --git a/drivers/spi/zynqmp_gqspi.c b/drivers/spi/zynqmp_gqspi.c index c7db43a09a..6641c2e9d5 100644 --- a/drivers/spi/zynqmp_gqspi.c +++ b/drivers/spi/zynqmp_gqspi.c @@ -320,12 +320,9 @@ static int zynqmp_qspi_set_speed(struct udevice *bus, uint speed) if (speed > plat->frequency) speed = plat->frequency;
- /* Set the clock frequency */
- confr = readl(®s->confr);
- if (speed == 0) {
/* Set baudrate x8, if the freq is 0 */baud_rate_val = GQSPI_DFLT_BAUD_RATE_VAL;- } else if (plat->speed_hz != speed) {
- if (plat->speed_hz != speed) {
/* Set the clock frequency *//* If speed == 0, default to lowest speed */@@ -335,13 +332,15 @@ static int zynqmp_qspi_set_speed(struct udevice *bus, uint speed) baud_rate_val = GQSPI_DFLT_BAUD_RATE_VAL;
plat->speed_hz = plat->frequency / (2 << baud_rate_val);
}
confr &= ~GQSPI_BAUD_DIV_MASK;
confr |= (baud_rate_val << 3);
writel(confr, ®s->confr);
zynqmp_qspi_set_tapdelay(bus, baud_rate_val);
debug("regs=%p, speed=%d\n", priv->regs, plat->speed_hz);
confr = readl(®s->confr);confr &= ~GQSPI_BAUD_DIV_MASK;confr |= (baud_rate_val << 3);writel(confr, ®s->confr);zynqmp_qspi_set_tapdelay(bus, baud_rate_val);debug("regs=%p, speed=%d\n", priv->regs, plat->speed_hz);}
return 0;
}
Ashok: Can you please review this patch?
Thanks, Michal