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 clsee@altera.com Cc: Dinh Nguyen dinguyen@opensource.altera.com Cc: Dinh Nguyen dinh.linux@gmail.com Cc: Marek Vasut marex@denx.de Cc: Stefan Roese sr@denx.de Cc: Vikas Manocha vikas.manocha@st.com Cc: Jagannadh Teki jteki@openedev.com Cc: Pavel Machek pavel@denx.de --- Changes for v2 - remove frequency set before calibration - introducing previous_hz to store requested frequency - prevent calibration run when request same frequency --- drivers/spi/cadence_qspi.c | 19 ++++++++++++------- drivers/spi/cadence_qspi.h | 1 + 2 files changed, 13 insertions(+), 7 deletions(-)

diff --git a/drivers/spi/cadence_qspi.c b/drivers/spi/cadence_qspi.c index 34a0f46..23c88d5 100644 --- a/drivers/spi/cadence_qspi.c +++ b/drivers/spi/cadence_qspi.c @@ -37,7 +37,7 @@ static int cadence_spi_write_speed(struct udevice *bus, uint hz) }

/* Calibration sequence to determine the read data capture delay register */ -static int spi_calibration(struct udevice *bus) +static int spi_calibration(struct udevice *bus, uint hz) { struct cadence_spi_platdata *plat = bus->platdata; struct cadence_spi_priv *priv = dev_get_priv(bus); @@ -46,6 +46,10 @@ static int spi_calibration(struct udevice *bus) unsigned int idcode = 0, temp = 0; int err = 0, i, range_lo = -1, range_hi = -1;

+ /* if calibrated frequency same as reqeusted, skip it */ + if (priv->qspi_calibrated_hz == hz) + return 0; + /* start with slowest clock (1 MHz) */ cadence_spi_write_speed(bus, 1000000);

@@ -64,7 +68,7 @@ static int spi_calibration(struct udevice *bus) }

/* use back the intended clock and find low range */ - cadence_spi_write_speed(bus, plat->max_hz); + cadence_spi_write_speed(bus, hz); for (i = 0; i < CQSPI_READ_CAPTURE_MAX_DELAY; i++) { /* Disable QSPI */ cadence_qspi_apb_controller_disable(base); @@ -111,7 +115,7 @@ static int spi_calibration(struct udevice *bus) (range_hi + range_lo) / 2, range_lo, range_hi);

/* just to ensure we do once only when speed or chip select change */ - priv->qspi_calibrated_hz = plat->max_hz; + priv->qspi_calibrated_hz = hz; priv->qspi_calibrated_cs = spi_chip_select(bus);

return 0; @@ -126,14 +130,15 @@ static int cadence_spi_set_speed(struct udevice *bus, uint hz) /* Disable QSPI */ cadence_qspi_apb_controller_disable(priv->regbase);

- cadence_spi_write_speed(bus, hz); - /* Calibration required for different SCLK speed or chip select */ - if (priv->qspi_calibrated_hz != plat->max_hz || + if (priv->previous_hz != hz || priv->qspi_calibrated_cs != spi_chip_select(bus)) { - err = spi_calibration(bus); + err = spi_calibration(bus, hz); if (err) return err; + + /* prevent calibration run when same as previous request */ + priv->previous_hz = hz; }

/* Enable QSPI */ diff --git a/drivers/spi/cadence_qspi.h b/drivers/spi/cadence_qspi.h index 98e57aa..2912e36 100644 --- a/drivers/spi/cadence_qspi.h +++ b/drivers/spi/cadence_qspi.h @@ -38,6 +38,7 @@ struct cadence_spi_priv { int qspi_is_init; unsigned int qspi_calibrated_hz; unsigned int qspi_calibrated_cs; + unsigned int previous_hz; };

/* Functions call declaration */