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authorJean Pihet <jean.pihet@newoldbits.com>2020-01-14 13:41:25 +0100
committerMark Brown <broonie@kernel.org>2020-01-14 15:26:05 +0000
commite7cc5cfbea4c9bd2c452cb81d0829e9259dd84d8 (patch)
treeac6522d791303c61165a16920fde5e00e011274b /drivers/spi/spi-ti-qspi.c
parente97f491450805fe6cbfd482b97b5427b21dec575 (diff)
downloadlinux-e7cc5cfbea4c9bd2c452cb81d0829e9259dd84d8.tar.bz2
spi: spi-ti-qspi: optimize byte-transfers
Optimize the 8-bit based transfers, as used by the SPI flash devices, by reading the data registers by 32 and 128 bits when possible and copy the contents to the receive buffer. The speed improvement is 4.9x using quad read. Signed-off-by: Jean Pihet <jean.pihet@newoldbits.com> Cc: Ryan Barnett <ryan.barnett@rockwellcollins.com> Cc: Conrad Ratschan <conrad.ratschan@rockwellcollins.com> Cc: Arnout Vandecappelle <arnout.vandecappelle@essensium.com> Link: https://lore.kernel.org/r/20200114124125.361429-3-jean.pihet@newoldbits.com Signed-off-by: Mark Brown <broonie@kernel.org>
Diffstat (limited to 'drivers/spi/spi-ti-qspi.c')
-rw-r--r--drivers/spi/spi-ti-qspi.c54
1 files changed, 51 insertions, 3 deletions
diff --git a/drivers/spi/spi-ti-qspi.c b/drivers/spi/spi-ti-qspi.c
index 0334e2926998..858fda8ac73e 100644
--- a/drivers/spi/spi-ti-qspi.c
+++ b/drivers/spi/spi-ti-qspi.c
@@ -314,6 +314,8 @@ static int qspi_read_msg(struct ti_qspi *qspi, struct spi_transfer *t,
{
int wlen;
unsigned int cmd;
+ u32 rx;
+ u8 rxlen, rx_wlen;
u8 *rxbuf;
rxbuf = t->rx_buf;
@@ -336,14 +338,60 @@ static int qspi_read_msg(struct ti_qspi *qspi, struct spi_transfer *t,
if (qspi_is_busy(qspi))
return -EBUSY;
+ switch (wlen) {
+ case 1:
+ /*
+ * Optimize the 8-bit words transfers, as used by
+ * the SPI flash devices.
+ */
+ if (count >= QSPI_WLEN_MAX_BYTES) {
+ rxlen = QSPI_WLEN_MAX_BYTES;
+ } else {
+ rxlen = min(count, 4);
+ }
+ rx_wlen = rxlen << 3;
+ cmd &= ~QSPI_WLEN_MASK;
+ cmd |= QSPI_WLEN(rx_wlen);
+ break;
+ default:
+ rxlen = wlen;
+ break;
+ }
+
ti_qspi_write(qspi, cmd, QSPI_SPI_CMD_REG);
if (ti_qspi_poll_wc(qspi)) {
dev_err(qspi->dev, "read timed out\n");
return -ETIMEDOUT;
}
+
switch (wlen) {
case 1:
- *rxbuf = readb(qspi->base + QSPI_SPI_DATA_REG);
+ /*
+ * Optimize the 8-bit words transfers, as used by
+ * the SPI flash devices.
+ */
+ if (count >= QSPI_WLEN_MAX_BYTES) {
+ u32 *rxp = (u32 *) rxbuf;
+ rx = readl(qspi->base + QSPI_SPI_DATA_REG_3);
+ *rxp++ = be32_to_cpu(rx);
+ rx = readl(qspi->base + QSPI_SPI_DATA_REG_2);
+ *rxp++ = be32_to_cpu(rx);
+ rx = readl(qspi->base + QSPI_SPI_DATA_REG_1);
+ *rxp++ = be32_to_cpu(rx);
+ rx = readl(qspi->base + QSPI_SPI_DATA_REG);
+ *rxp++ = be32_to_cpu(rx);
+ } else {
+ u8 *rxp = rxbuf;
+ rx = readl(qspi->base + QSPI_SPI_DATA_REG);
+ if (rx_wlen >= 8)
+ *rxp++ = rx >> (rx_wlen - 8);
+ if (rx_wlen >= 16)
+ *rxp++ = rx >> (rx_wlen - 16);
+ if (rx_wlen >= 24)
+ *rxp++ = rx >> (rx_wlen - 24);
+ if (rx_wlen >= 32)
+ *rxp++ = rx;
+ }
break;
case 2:
*((u16 *)rxbuf) = readw(qspi->base + QSPI_SPI_DATA_REG);
@@ -352,8 +400,8 @@ static int qspi_read_msg(struct ti_qspi *qspi, struct spi_transfer *t,
*((u32 *)rxbuf) = readl(qspi->base + QSPI_SPI_DATA_REG);
break;
}
- rxbuf += wlen;
- count -= wlen;
+ rxbuf += rxlen;
+ count -= rxlen;
}
return 0;