cadence_qspi: fix odd byte read issue in STIG mode

In DDR mode, even bytes are read using DMA, while the remaining odd
bytes are read using STIG mode. However, the data is not correctly
transferred into the flash read data lower register because the
supplementary byte of the STIG opcode is not being written to the
opcode extension register, resulting in incorrect data being read.

To resolve this issue, when using STIG transactions, the corresponding
supplementary byte of any STIG opcode must be defined in the Opcode
Extension Register (Lower). Issue has been observed on the Macronix
MX66UM2G45G flashes.

Signed-off-by: Prasad Kummari <prasad.kummari@amd.com>
Signed-off-by: Venkatesh Yadav Abbarapu <venkatesh.abbarapu@amd.com>
Link: https://lore.kernel.org/r/20250702053953.640046-1-venkatesh.abbarapu@amd.com
Signed-off-by: Michal Simek <michal.simek@amd.com>

diff --git a/drivers/spi/cadence_ospi_versal.c b/drivers/spi/cadence_ospi_versal.c
index fbeb0c6..6dc6fbe 100644 (file)
--- a/drivers/spi/cadence_ospi_versal.c
+++ b/drivers/spi/cadence_ospi_versal.c
@@ -20,7 +20,7 @@
 int cadence_qspi_apb_dma_read(struct cadence_spi_priv *priv,
                              const struct spi_mem_op *op)
 {
-       u32 reg, ret, rx_rem, n_rx, bytes_to_dma, data;
+       u32 reg, ret, rx_rem, n_rx, bytes_to_dma, data, status;
        u8 opcode, addr_bytes, *rxbuf, dummy_cycles;
 
        n_rx = op->data.nbytes;
@@ -87,6 +87,16 @@ int cadence_qspi_apb_dma_read(struct cadence_spi_priv *priv,
                                   CQSPI_REG_SIZE_ADDRESS_MASK;
 
                opcode = CMD_4BYTE_FAST_READ;
+
+               /* Set up command opcode extension. */
+               status = readl(priv->regbase + CQSPI_REG_CONFIG);
+               if (status & CQSPI_REG_CONFIG_DTR_PROTO) {
+                       ret = cadence_qspi_setup_opcode_ext(priv, op,
+                                                           CQSPI_REG_OP_EXT_STIG_LSB);
+                       if (ret)
+                               return ret;
+               }
+
                dummy_cycles = 8;
                writel((dummy_cycles << CQSPI_REG_RD_INSTR_DUMMY_LSB) | opcode,
                       priv->regbase + CQSPI_REG_RD_INSTR);

diff --git a/drivers/spi/cadence_qspi.h b/drivers/spi/cadence_qspi.h
index 80510f2..879e7f8 100644 (file)
--- a/drivers/spi/cadence_qspi.h
+++ b/drivers/spi/cadence_qspi.h
@@ -320,5 +320,7 @@ int cadence_qspi_flash_reset(struct udevice *dev);
 ofnode cadence_qspi_get_subnode(struct udevice *dev);
 void cadence_qspi_apb_enable_linear_mode(bool enable);
 int cadence_device_reset(struct udevice *dev);
-
+int cadence_qspi_setup_opcode_ext(struct cadence_spi_priv *priv,
+                                 const struct spi_mem_op *op,
+                                 unsigned int shift);
 #endif /* __CADENCE_QSPI_H__ */

diff --git a/drivers/spi/cadence_qspi_apb.c b/drivers/spi/cadence_qspi_apb.c
index ebfcae9..6f89d3a 100644 (file)
--- a/drivers/spi/cadence_qspi_apb.c
+++ b/drivers/spi/cadence_qspi_apb.c
@@ -384,9 +384,9 @@ int cadence_qspi_apb_exec_flash_cmd(void *reg_base, unsigned int reg)
        return 0;
 }
 
-static int cadence_qspi_setup_opcode_ext(struct cadence_spi_priv *priv,
-                                        const struct spi_mem_op *op,
-                                        unsigned int shift)
+int cadence_qspi_setup_opcode_ext(struct cadence_spi_priv *priv,
+                                 const struct spi_mem_op *op,
+                                 unsigned int shift)
 {
        unsigned int reg;
        u8 ext;