From d9aa19efa8a6c20d51b7884de0a7f8dae3f835d2 Mon Sep 17 00:00:00 2001 From: Brandon Maier Date: Wed, 20 Jan 2021 14:28:30 -0600 Subject: [PATCH] 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 CC: jagan@amarulasolutions.com CC: michal.simek@xilinx.com CC: Ashok Reddy Soma Signed-off-by: Michal Simek --- 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 bd25511aae..116319526f 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 */ 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, ®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; } -- GitLab