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authorBrandon Maier <brandon.maier@rockwellcollins.com>2021-01-20 14:28:30 -0600
committerMichal Simek <michal.simek@xilinx.com>2021-02-23 14:56:59 +0100
commitd9aa19efa8a6c20d51b7884de0a7f8dae3f835d2 (patch)
treebc9a2aad017b6c45c3fcb0c852bd3dc7debc6c9b
parent3600d47b734129c9cb9772c587d0bf1fbc458cc6 (diff)
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spi: zynqmp_gqspi: fix set_speed bug on multiple runs
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> Signed-off-by: Michal Simek <michal.simek@xilinx.com>
-rw-r--r--drivers/spi/zynqmp_gqspi.c23
1 files changed, 11 insertions, 12 deletions
diff --git a/drivers/spi/zynqmp_gqspi.c b/drivers/spi/zynqmp_gqspi.c
index bd25511..1163195 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(&regs->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 */
while ((baud_rate_val < 8) &&
((plat->frequency /
(2 << baud_rate_val)) > 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, &regs->confr);
- zynqmp_qspi_set_tapdelay(bus, baud_rate_val);
- debug("regs=%p, speed=%d\n", priv->regs, plat->speed_hz);
+ confr = readl(&regs->confr);
+ confr &= ~GQSPI_BAUD_DIV_MASK;
+ confr |= (baud_rate_val << 3);
+ writel(confr, &regs->confr);
+ zynqmp_qspi_set_tapdelay(bus, baud_rate_val);
+
+ debug("regs=%p, speed=%d\n", priv->regs, plat->speed_hz);
+ }
return 0;
}