Make flash writes 32 bit aligned by using bounce buffers to deal with
non 32 bit aligned buffers. Allocate a 512 byte bounce buffer (max known
page size currently) for this case.
This is required because as per TI K2G TRM[1], the external master is
only permitted to issue 32-bit data interface writes until the last word
of an indirect transfer. Otherwise indirect writes is known to fail
sometimes.

[1] http://www.ti.com/lit/ug/spruhy8g/spruhy8g.pdf

Signed-off-by: Vignesh R <vigne...@ti.com>
---
 drivers/spi/cadence_qspi.c     | 13 ++++++++++++-
 drivers/spi/cadence_qspi.h     |  1 +
 drivers/spi/cadence_qspi_apb.c | 10 +++++-----
 3 files changed, 18 insertions(+), 6 deletions(-)

diff --git a/drivers/spi/cadence_qspi.c b/drivers/spi/cadence_qspi.c
index 991a7160bdb8..49c9b477e678 100644
--- a/drivers/spi/cadence_qspi.c
+++ b/drivers/spi/cadence_qspi.c
@@ -158,6 +158,10 @@ static int cadence_spi_probe(struct udevice *bus)
 
        priv->regbase = plat->regbase;
        priv->ahbbase = plat->ahbbase;
+       /* Bounce buf to handle unaligned writes. 512B is max pagesize */
+       priv->bounce_buf = malloc(512);
+       if (!priv->bounce_buf)
+               return -ENOMEM;
 
        if (!priv->qspi_is_init) {
                cadence_qspi_apb_controller_init(plat);
@@ -259,8 +263,15 @@ static int cadence_spi_xfer(struct udevice *dev, unsigned 
int bitlen,
                        err = cadence_qspi_apb_indirect_write_setup
                                (plat, priv->cmd_len, cmd_buf);
                        if (!err) {
+                               const u8 *txbuf = dout;
+
+                               if ((uintptr_t)txbuf % 4) {
+                                       memcpy(priv->bounce_buf, dout,
+                                              data_bytes);
+                                       txbuf = priv->bounce_buf;
+                               }
                                err = cadence_qspi_apb_indirect_write_execute
-                               (plat, data_bytes, dout);
+                               (plat, data_bytes, txbuf);
                        }
                break;
                default:
diff --git a/drivers/spi/cadence_qspi.h b/drivers/spi/cadence_qspi.h
index 83154210bd95..c97419af3de3 100644
--- a/drivers/spi/cadence_qspi.h
+++ b/drivers/spi/cadence_qspi.h
@@ -43,6 +43,7 @@ struct cadence_spi_priv {
        unsigned int    qspi_calibrated_hz;
        unsigned int    qspi_calibrated_cs;
        unsigned int    previous_hz;
+       void            *bounce_buf;
 };
 
 /* Functions call declaration */
diff --git a/drivers/spi/cadence_qspi_apb.c b/drivers/spi/cadence_qspi_apb.c
index fa8af33ae19b..fd3ece4cb129 100644
--- a/drivers/spi/cadence_qspi_apb.c
+++ b/drivers/spi/cadence_qspi_apb.c
@@ -727,11 +727,11 @@ int cadence_qspi_apb_indirect_write_execute(struct 
cadence_spi_platdata *plat,
 
        while (remaining > 0) {
                write_bytes = remaining > page_size ? page_size : remaining;
-               /* Handle non-4-byte aligned access to avoid data abort. */
-               if (((uintptr_t)txbuf % 4) || (write_bytes % 4))
-                       writesb(plat->ahbbase, txbuf, write_bytes);
-               else
-                       writesl(plat->ahbbase, txbuf, write_bytes >> 2);
+               writesl(plat->ahbbase, txbuf, write_bytes >> 2);
+               if (write_bytes % 4)
+                       writesb(plat->ahbbase,
+                               txbuf + rounddown(write_bytes, 4),
+                               write_bytes % 4);
 
                ret = wait_for_bit("QSPI", plat->regbase + CQSPI_REG_SDRAMLEVEL,
                                   CQSPI_REG_SDRAMLEVEL_WR_MASK <<
-- 
2.15.1

_______________________________________________
U-Boot mailing list
U-Boot@lists.denx.de
https://lists.denx.de/listinfo/u-boot

Reply via email to