By reading the 32 bits data register and copy the contents to the
receive buffer, according to the single/dual/quad read mode and
the data length to read.
The speed improvement is 3.5x using quad read.
---
drivers/spi/spi-ti-qspi.c | 48 ++++++++++++++++++++++++++-------------
1 file changed, 32 insertions(+), 16 deletions(-)
diff --git a/drivers/spi/spi-ti-qspi.c b/drivers/spi/spi-ti-qspi.c
index 13916232a959..65ec3bcb25ae 100644
--- a/drivers/spi/spi-ti-qspi.c
+++ b/drivers/spi/spi-ti-qspi.c
@@ -313,24 +313,25 @@ static int qspi_write_msg(struct ti_qspi *qspi, struct spi_transfer *t,
static int qspi_read_msg(struct ti_qspi *qspi, struct spi_transfer *t,
int count)
{
- int wlen;
unsigned int cmd;
+ u32 rx;
u8 *rxbuf;
+ u8 xfer_len;
rxbuf = t->rx_buf;
cmd = qspi->cmd;
+ /* Optimize the transfers for dual and quad read */
switch (t->rx_nbits) {
- case SPI_NBITS_DUAL:
- cmd |= QSPI_RD_DUAL;
- break;
case SPI_NBITS_QUAD:
- cmd |= QSPI_RD_QUAD;
+ cmd |= QSPI_RD_QUAD | QSPI_WLEN(32);
+ break;
+ case SPI_NBITS_DUAL:
+ cmd |= QSPI_RD_DUAL | QSPI_WLEN(16);
break;
default:
- cmd |= QSPI_RD_SNGL;
+ cmd |= QSPI_RD_SNGL | QSPI_WLEN(8);
break;
}
- wlen = t->bits_per_word >> 3; /* in bytes */
while (count) {
dev_dbg(qspi->dev, "rx cmd %08x dc %08x\n", cmd, qspi->dc);
@@ -342,19 +343,34 @@ static int qspi_read_msg(struct ti_qspi *qspi, struct spi_transfer *t,
dev_err(qspi->dev, "read timed out\n");
return -ETIMEDOUT;
}
- switch (wlen) {
- case 1:
- *rxbuf = readb(qspi->base + QSPI_SPI_DATA_REG);
+
+ /* Optimize the transfers for dual and quad read */
+ rx = readl(qspi->base + QSPI_SPI_DATA_REG);
+ switch (t->rx_nbits) {
+ case SPI_NBITS_QUAD:
+ if (count >= 1)
+ *rxbuf++ = rx >> 24;
+ if (count >= 2)
+ *rxbuf++ = rx >> 16;
+ if (count >= 3)
+ *rxbuf++ = rx >> 8;
+ if (count >= 4)
+ *rxbuf++ = rx;
+ xfer_len = min(count, 4);
break;
- case 2:
- *((u16 *)rxbuf) = readw(qspi->base + QSPI_SPI_DATA_REG);
+ case SPI_NBITS_DUAL:
+ if (count >= 1)
+ *rxbuf++ = rx >> 8;
+ if (count >= 2)
+ *rxbuf++ = rx;
+ xfer_len = min(count, 2);
break;
- case 4:
- *((u32 *)rxbuf) = readl(qspi->base + QSPI_SPI_DATA_REG);
+ default:
+ *rxbuf++ = rx;
+ xfer_len = 1;
break;
}
- rxbuf += wlen;
- count -= wlen;
+ count -= xfer_len;
}
return 0;
--
2.23.0
