spi/omap2_mcspi: add turbo mode support
Turbo mode allows to read data to shift register when rx-buffer
is full thus improving the perfomance. This feature is available
for RX-only mode.
In PIO turbo mode when the penultimate word is available
in RX-buffer the controller should be disabled before reading data
to prevent the next transaction triggering. The controller itself
handles the last word to be correctly loaded to shift-register and
then transferred to RX-buffer.
The turbo mode is enabled by setting turbo_mode parameter to 1.
This parameter is a part of omap2_mcspi_device_config structure
which is passed through the spi_device controller_data pointer.
Signed-off-by: Roman Tereshonkov <roman.tereshonkov@nokia.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
diff --git a/drivers/spi/omap2_mcspi.c b/drivers/spi/omap2_mcspi.c
index e6d08b8..6df8553 100644
--- a/drivers/spi/omap2_mcspi.c
+++ b/drivers/spi/omap2_mcspi.c
@@ -38,7 +38,7 @@
#include <plat/dma.h>
#include <plat/clock.h>
-
+#include <plat/mcspi.h>
#define OMAP2_MCSPI_MAX_FREQ 48000000
@@ -229,6 +229,8 @@
l = enable ? OMAP2_MCSPI_CHCTRL_EN : 0;
mcspi_write_cs_reg(spi, OMAP2_MCSPI_CHCTRL0, l);
+ /* Flash post-writes */
+ mcspi_read_cs_reg(spi, OMAP2_MCSPI_CHCTRL0);
}
static void omap2_mcspi_force_cs(struct spi_device *spi, int cs_active)
@@ -303,11 +305,14 @@
unsigned int count, c;
unsigned long base, tx_reg, rx_reg;
int word_len, data_type, element_count;
+ int elements;
+ u32 l;
u8 * rx;
const u8 * tx;
mcspi = spi_master_get_devdata(spi->master);
mcspi_dma = &mcspi->dma_channels[spi->chip_select];
+ l = mcspi_cached_chconf0(spi);
count = xfer->len;
c = count;
@@ -346,8 +351,12 @@
}
if (rx != NULL) {
+ elements = element_count - 1;
+ if (l & OMAP2_MCSPI_CHCONF_TURBO)
+ elements--;
+
omap_set_dma_transfer_params(mcspi_dma->dma_rx_channel,
- data_type, element_count - 1, 1,
+ data_type, elements, 1,
OMAP_DMA_SYNC_ELEMENT,
mcspi_dma->dma_rx_sync_dev, 1);
@@ -379,17 +388,42 @@
wait_for_completion(&mcspi_dma->dma_rx_completion);
dma_unmap_single(NULL, xfer->rx_dma, count, DMA_FROM_DEVICE);
omap2_mcspi_set_enable(spi, 0);
+
+ if (l & OMAP2_MCSPI_CHCONF_TURBO) {
+
+ if (likely(mcspi_read_cs_reg(spi, OMAP2_MCSPI_CHSTAT0)
+ & OMAP2_MCSPI_CHSTAT_RXS)) {
+ u32 w;
+
+ w = mcspi_read_cs_reg(spi, OMAP2_MCSPI_RX0);
+ if (word_len <= 8)
+ ((u8 *)xfer->rx_buf)[elements++] = w;
+ else if (word_len <= 16)
+ ((u16 *)xfer->rx_buf)[elements++] = w;
+ else /* word_len <= 32 */
+ ((u32 *)xfer->rx_buf)[elements++] = w;
+ } else {
+ dev_err(&spi->dev,
+ "DMA RX penultimate word empty");
+ count -= (word_len <= 8) ? 2 :
+ (word_len <= 16) ? 4 :
+ /* word_len <= 32 */ 8;
+ omap2_mcspi_set_enable(spi, 1);
+ return count;
+ }
+ }
+
if (likely(mcspi_read_cs_reg(spi, OMAP2_MCSPI_CHSTAT0)
& OMAP2_MCSPI_CHSTAT_RXS)) {
u32 w;
w = mcspi_read_cs_reg(spi, OMAP2_MCSPI_RX0);
if (word_len <= 8)
- ((u8 *)xfer->rx_buf)[element_count - 1] = w;
+ ((u8 *)xfer->rx_buf)[elements] = w;
else if (word_len <= 16)
- ((u16 *)xfer->rx_buf)[element_count - 1] = w;
+ ((u16 *)xfer->rx_buf)[elements] = w;
else /* word_len <= 32 */
- ((u32 *)xfer->rx_buf)[element_count - 1] = w;
+ ((u32 *)xfer->rx_buf)[elements] = w;
} else {
dev_err(&spi->dev, "DMA RX last word empty");
count -= (word_len <= 8) ? 1 :
@@ -433,7 +467,6 @@
word_len = cs->word_len;
l = mcspi_cached_chconf0(spi);
- l &= ~OMAP2_MCSPI_CHCONF_TRM_MASK;
/* We store the pre-calculated register addresses on stack to speed
* up the transfer loop. */
@@ -468,11 +501,26 @@
dev_err(&spi->dev, "RXS timed out\n");
goto out;
}
- /* prevent last RX_ONLY read from triggering
- * more word i/o: switch to rx+tx
- */
- if (c == 0 && tx == NULL)
- mcspi_write_chconf0(spi, l);
+
+ if (c == 1 && tx == NULL &&
+ (l & OMAP2_MCSPI_CHCONF_TURBO)) {
+ omap2_mcspi_set_enable(spi, 0);
+ *rx++ = __raw_readl(rx_reg);
+#ifdef VERBOSE
+ dev_dbg(&spi->dev, "read-%d %02x\n",
+ word_len, *(rx - 1));
+#endif
+ if (mcspi_wait_for_reg_bit(chstat_reg,
+ OMAP2_MCSPI_CHSTAT_RXS) < 0) {
+ dev_err(&spi->dev,
+ "RXS timed out\n");
+ goto out;
+ }
+ c = 0;
+ } else if (c == 0 && tx == NULL) {
+ omap2_mcspi_set_enable(spi, 0);
+ }
+
*rx++ = __raw_readl(rx_reg);
#ifdef VERBOSE
dev_dbg(&spi->dev, "read-%d %02x\n",
@@ -506,11 +554,26 @@
dev_err(&spi->dev, "RXS timed out\n");
goto out;
}
- /* prevent last RX_ONLY read from triggering
- * more word i/o: switch to rx+tx
- */
- if (c == 0 && tx == NULL)
- mcspi_write_chconf0(spi, l);
+
+ if (c == 2 && tx == NULL &&
+ (l & OMAP2_MCSPI_CHCONF_TURBO)) {
+ omap2_mcspi_set_enable(spi, 0);
+ *rx++ = __raw_readl(rx_reg);
+#ifdef VERBOSE
+ dev_dbg(&spi->dev, "read-%d %04x\n",
+ word_len, *(rx - 1));
+#endif
+ if (mcspi_wait_for_reg_bit(chstat_reg,
+ OMAP2_MCSPI_CHSTAT_RXS) < 0) {
+ dev_err(&spi->dev,
+ "RXS timed out\n");
+ goto out;
+ }
+ c = 0;
+ } else if (c == 0 && tx == NULL) {
+ omap2_mcspi_set_enable(spi, 0);
+ }
+
*rx++ = __raw_readl(rx_reg);
#ifdef VERBOSE
dev_dbg(&spi->dev, "read-%d %04x\n",
@@ -544,11 +607,26 @@
dev_err(&spi->dev, "RXS timed out\n");
goto out;
}
- /* prevent last RX_ONLY read from triggering
- * more word i/o: switch to rx+tx
- */
- if (c == 0 && tx == NULL)
- mcspi_write_chconf0(spi, l);
+
+ if (c == 4 && tx == NULL &&
+ (l & OMAP2_MCSPI_CHCONF_TURBO)) {
+ omap2_mcspi_set_enable(spi, 0);
+ *rx++ = __raw_readl(rx_reg);
+#ifdef VERBOSE
+ dev_dbg(&spi->dev, "read-%d %08x\n",
+ word_len, *(rx - 1));
+#endif
+ if (mcspi_wait_for_reg_bit(chstat_reg,
+ OMAP2_MCSPI_CHSTAT_RXS) < 0) {
+ dev_err(&spi->dev,
+ "RXS timed out\n");
+ goto out;
+ }
+ c = 0;
+ } else if (c == 0 && tx == NULL) {
+ omap2_mcspi_set_enable(spi, 0);
+ }
+
*rx++ = __raw_readl(rx_reg);
#ifdef VERBOSE
dev_dbg(&spi->dev, "read-%d %08x\n",
@@ -568,6 +646,7 @@
dev_err(&spi->dev, "EOT timed out\n");
}
out:
+ omap2_mcspi_set_enable(spi, 1);
return count - c;
}
@@ -797,6 +876,7 @@
struct spi_transfer *t = NULL;
int cs_active = 0;
struct omap2_mcspi_cs *cs;
+ struct omap2_mcspi_device_config *cd;
int par_override = 0;
int status = 0;
u32 chconf;
@@ -809,6 +889,7 @@
spi = m->spi;
cs = spi->controller_state;
+ cd = spi->controller_data;
omap2_mcspi_set_enable(spi, 1);
list_for_each_entry(t, &m->transfers, transfer_list) {
@@ -832,10 +913,19 @@
chconf = mcspi_cached_chconf0(spi);
chconf &= ~OMAP2_MCSPI_CHCONF_TRM_MASK;
+ chconf &= ~OMAP2_MCSPI_CHCONF_TURBO;
+
if (t->tx_buf == NULL)
chconf |= OMAP2_MCSPI_CHCONF_TRM_RX_ONLY;
else if (t->rx_buf == NULL)
chconf |= OMAP2_MCSPI_CHCONF_TRM_TX_ONLY;
+
+ if (cd && cd->turbo_mode && t->tx_buf == NULL) {
+ /* Turbo mode is for more than one word */
+ if (t->len > ((cs->word_len + 7) >> 3))
+ chconf |= OMAP2_MCSPI_CHCONF_TURBO;
+ }
+
mcspi_write_chconf0(spi, chconf);
if (t->len) {