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Subject[PATCH 08/11] spi: dw: update buffer for enhanced spi mode
Date
In enhanced spi mode we will be writing the address to a single FIFO
location instead of writing to multiple FIFOs in the standard SPI mode.
Save the cmd and address bytes in the buffer accordingly.

Signed-off-by: Sudip Mukherjee <sudip.mukherjee@sifive.com>
---
drivers/spi/spi-dw-core.c | 55 ++++++++++++++++++++++++++++++++++-----
1 file changed, 48 insertions(+), 7 deletions(-)

diff --git a/drivers/spi/spi-dw-core.c b/drivers/spi/spi-dw-core.c
index 8cb30540ad5b..2564a2276572 100644
--- a/drivers/spi/spi-dw-core.c
+++ b/drivers/spi/spi-dw-core.c
@@ -520,7 +520,8 @@ static bool dw_spi_supports_mem_op(struct spi_mem *mem,
return spi_mem_default_supports_op(mem, op);
}

-static int dw_spi_init_mem_buf(struct dw_spi *dws, const struct spi_mem_op *op)
+static int dw_spi_init_mem_buf(struct dw_spi *dws, const struct spi_mem_op *op,
+ bool enhanced_spi)
{
unsigned int i, j, len;
u8 *out;
@@ -548,17 +549,57 @@ static int dw_spi_init_mem_buf(struct dw_spi *dws, const struct spi_mem_op *op)
*/
for (i = 0; i < op->cmd.nbytes; ++i)
out[i] = DW_SPI_GET_BYTE(op->cmd.opcode, op->cmd.nbytes - i - 1);
- for (j = 0; j < op->addr.nbytes; ++i, ++j)
- out[i] = DW_SPI_GET_BYTE(op->addr.val, op->addr.nbytes - j - 1);
- for (j = 0; j < op->dummy.nbytes; ++i, ++j)
- out[i] = 0x0;
+
+ if (enhanced_spi) {
+ /*
+ * Fill the remaining spaces of dws->reg_io_width bytes
+ * size register with zero for cmd.
+ */
+ for (; i < dws->reg_io_width; ++i)
+ out[i] = 0;
+ /*
+ * Copy the address bytes in dws->reg_io_width bytes size
+ * register and fill remaining spaces with zero.
+ */
+ for (j = op->addr.nbytes; j > 0; ++i, --j)
+ out[i] = DW_SPI_GET_BYTE(op->addr.val, op->addr.nbytes - j);
+ for (j = op->addr.nbytes; j < dws->reg_io_width; ++i, ++j)
+ out[i] = 0;
+ } else {
+ for (j = 0; j < op->addr.nbytes; ++i, ++j)
+ out[i] = DW_SPI_GET_BYTE(op->addr.val, op->addr.nbytes - j - 1);
+ }
+
+ if (!enhanced_spi) {
+ /*
+ * dummy bytes are not needed in enhanced mode as
+ * wait_cycles specified as number of SPI clock cycles
+ * between control frames transmit and data reception
+ * will be mentioned in enhanced spi mode.
+ */
+ for (j = 0; j < op->dummy.nbytes; ++i, ++j)
+ out[i] = 0x0;
+ }

if (op->data.dir == SPI_MEM_DATA_OUT)
memcpy(&out[i], op->data.buf.out, op->data.nbytes);

dws->n_bytes = 1;
dws->tx = out;
- dws->tx_len = len;
+
+ if (enhanced_spi) {
+ /*
+ * In enhanced mode cmd will be one FIFO and address
+ * will be one more FIFO.
+ */
+ dws->tx_len = 1;
+ if (op->addr.nbytes)
+ dws->tx_len += 1;
+ if (op->data.dir == SPI_MEM_DATA_OUT)
+ dws->tx_len += op->data.nbytes;
+ } else {
+ dws->tx_len = len;
+ }
if (op->data.dir == SPI_MEM_DATA_IN) {
dws->rx = op->data.buf.in;
dws->rx_len = op->data.nbytes;
@@ -744,7 +785,7 @@ static int dw_spi_exec_mem_op(struct spi_mem *mem, const struct spi_mem_op *op)
* Collect the outbound data into a single buffer to speed the
* transmission up at least on the initial stage.
*/
- ret = dw_spi_init_mem_buf(dws, op);
+ ret = dw_spi_init_mem_buf(dws, op, enhanced_spi);
if (ret)
return ret;

--
2.30.2
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