[PATCH v9 06/28] spi: cadence-qspi: Add a small delay before indirect writes
Pratyush Yadav
p.yadav at ti.com
Wed May 5 11:41:16 CEST 2021
Once the start bit is toggled it takes a small amount of time before it
is internally synchronized. This means we can't start writing during
that part. So add a small delay to allow the bit to be synchronized.
Signed-off-by: Pratyush Yadav <p.yadav at ti.com>
---
drivers/spi/cadence_qspi.c | 4 ++++
drivers/spi/cadence_qspi.h | 1 +
drivers/spi/cadence_qspi_apb.c | 6 ++++++
3 files changed, 11 insertions(+)
diff --git a/drivers/spi/cadence_qspi.c b/drivers/spi/cadence_qspi.c
index de7628de27..a961193cdc 100644
--- a/drivers/spi/cadence_qspi.c
+++ b/drivers/spi/cadence_qspi.c
@@ -20,6 +20,8 @@
#include <linux/sizes.h>
#include "cadence_qspi.h"
+#define NSEC_PER_SEC 1000000000L
+
#define CQSPI_STIG_READ 0
#define CQSPI_STIG_WRITE 1
#define CQSPI_READ 2
@@ -208,6 +210,8 @@ static int cadence_spi_probe(struct udevice *bus)
priv->qspi_is_init = 1;
}
+ plat->wr_delay = 50 * DIV_ROUND_UP(NSEC_PER_SEC, plat->ref_clk_hz);
+
return 0;
}
diff --git a/drivers/spi/cadence_qspi.h b/drivers/spi/cadence_qspi.h
index b06d7750e2..5c745541a6 100644
--- a/drivers/spi/cadence_qspi.h
+++ b/drivers/spi/cadence_qspi.h
@@ -27,6 +27,7 @@ struct cadence_spi_plat {
fdt_addr_t ahbsize;
bool use_dac_mode;
int read_delay;
+ u32 wr_delay;
/* Flash parameters */
u32 page_size;
diff --git a/drivers/spi/cadence_qspi_apb.c b/drivers/spi/cadence_qspi_apb.c
index b051f462ed..92e57730bd 100644
--- a/drivers/spi/cadence_qspi_apb.c
+++ b/drivers/spi/cadence_qspi_apb.c
@@ -730,6 +730,12 @@ cadence_qspi_apb_indirect_write_execute(struct cadence_spi_plat *plat,
writel(CQSPI_REG_INDIRECTWR_START,
plat->regbase + CQSPI_REG_INDIRECTWR);
+ /*
+ * Some delay is required for the above bit to be internally
+ * synchronized by the QSPI module.
+ */
+ ndelay(plat->wr_delay);
+
while (remaining > 0) {
write_bytes = remaining > page_size ? page_size : remaining;
writesl(plat->ahbbase, bb_txbuf, write_bytes >> 2);
--
2.30.0
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