[PATCH] mtd: spi-nor: cadence-quadspi: write upto 8-bytes data in STIG mode

[Purna Chandra Mandal]

cadence-quadspi controller allows upto eight bytes of data to
be written in software Triggered Instruction generator (STIG) mode
of operation. Lower 4 bytes are written through writedatalower and
upper 4 bytes by writedataupper register.

This patch allows all the 8 bytes to be written.

Signed-off-by: Purna Chandra Mandal <purna.chandra.man...@intel.com>
---

 drivers/mtd/spi-nor/cadence-quadspi.c | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/drivers/mtd/spi-nor/cadence-quadspi.c 
b/drivers/mtd/spi-nor/cadence-quadspi.c
index 04cedd3a2bf6..7f78f9409ddd 100644
--- a/drivers/mtd/spi-nor/cadence-quadspi.c
+++ b/drivers/mtd/spi-nor/cadence-quadspi.c
@@ -418,9 +418,10 @@ static int cqspi_command_write(struct spi_nor *nor, const 
u8 opcode,
        void __iomem *reg_base = cqspi->iobase;
        unsigned int reg;
        unsigned int data;
+       u32 write_len;
        int ret;
 
-       if (n_tx > 4 || (n_tx && !txbuf)) {
+       if (n_tx > CQSPI_STIG_DATA_LEN_MAX || (n_tx && !txbuf)) {
                dev_err(nor->dev,
                        "Invalid input argument, cmdlen %d txbuf 0x%p\n",
                        n_tx, txbuf);
@@ -433,10 +434,18 @@ static int cqspi_command_write(struct spi_nor *nor, const 
u8 opcode,
                reg |= ((n_tx - 1) & CQSPI_REG_CMDCTRL_WR_BYTES_MASK)
                        << CQSPI_REG_CMDCTRL_WR_BYTES_LSB;
                data = 0;
-               memcpy(&data, txbuf, n_tx);
+               write_len = (n_tx > 4) ? 4 : n_tx;
+               memcpy(&data, txbuf, write_len);
+               txbuf += write_len;
                writel(data, reg_base + CQSPI_REG_CMDWRITEDATALOWER);
-       }
 
+               if (n_tx > 4) {
+                       data = 0;
+                       write_len = n_tx - 4;
+                       memcpy(&data, txbuf, write_len);
+                       writel(data, reg_base + CQSPI_REG_CMDWRITEDATAUPPER);
+               }
+       }
        ret = cqspi_exec_flash_cmd(cqspi, reg);
        return ret;
 }
-- 
2.13.0