[PATCH v2 4/4] spi: amd: Don't wait for a write-only transfer to finish

From: Lucas Tanure
Date: Fri Sep 10 2021 - 07:15:52 EST


Return from a write-only transfer without waiting for
it to finish
But wait before a new transfer as the previous may
still happening and also wait before reading the data
from the FIFO

Signed-off-by: Lucas Tanure <tanureal@xxxxxxxxxxxxxxxxxxxxx>
---

Changes in v2:
Add wait before read data
New explanation

drivers/spi/spi-amd.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/spi/spi-amd.c b/drivers/spi/spi-amd.c
index 97838b57871c..4b3ac7aceaf6 100644
--- a/drivers/spi/spi-amd.c
+++ b/drivers/spi/spi-amd.c
@@ -115,11 +115,18 @@ static int amd_spi_busy_wait(struct amd_spi *amd_spi)
return 0;
}

-static void amd_spi_execute_opcode(struct amd_spi *amd_spi)
+static int amd_spi_execute_opcode(struct amd_spi *amd_spi)
{
+ int ret;
+
+ ret = amd_spi_busy_wait(amd_spi);
+ if (ret)
+ return ret;
+
/* Set ExecuteOpCode bit in the CTRL0 register */
amd_spi_setclear_reg32(amd_spi, AMD_SPI_CTRL0_REG, AMD_SPI_EXEC_CMD, AMD_SPI_EXEC_CMD);
- amd_spi_busy_wait(amd_spi);
+
+ return 0;
}

static int amd_spi_master_setup(struct spi_device *spi)
@@ -178,6 +185,7 @@ static inline int amd_spi_fifo_xfer(struct amd_spi *amd_spi,
amd_spi_clear_fifo_ptr(amd_spi);
/* Execute command */
amd_spi_execute_opcode(amd_spi);
+ amd_spi_busy_wait(amd_spi);
/* Read data from FIFO to receive buffer */
for (i = 0; i < rx_len; i++)
buf[i] = amd_spi_readreg8(amd_spi, AMD_SPI_FIFO_BASE + tx_len + i);
--
2.33.0