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authorVladimir Oltean <olteanv@gmail.com>2019-12-27 03:24:17 +0200
committerMark Brown <broonie@kernel.org>2019-12-27 23:03:43 +0000
commit862dd2a946aa1417f013fb748e2aa0f4349b405b (patch)
tree8710c9f5a8d6899b3f0d9e931fa7a43b2898e2dd /drivers/spi
parent9cd34efbd3012171c102910ce17ee632a3cccb44 (diff)
spi: Don't look at TX buffer for PTP system timestamping
The API for PTP system timestamping (associating a SPI transaction with the system time at which it was transferred) is flawed: it assumes that the xfer->tx_buf pointer will always be present. This is, of course, not always the case. So introduce a "progress" variable that denotes how many word have been transferred. Fix the Freescale DSPI driver, the only user of the API so far, in the same patch. Fixes: b42faeee718c ("spi: Add a PTP system timestamp to the transfer structure") Fixes: d6b71dfaeeba ("spi: spi-fsl-dspi: Implement the PTP system timestamping for TCFQ mode") Signed-off-by: Vladimir Oltean <olteanv@gmail.com> Link: https://lore.kernel.org/r/20191227012417.1057-1-olteanv@gmail.com Signed-off-by: Mark Brown <broonie@kernel.org>
Diffstat (limited to 'drivers/spi')
-rw-r--r--drivers/spi/spi-fsl-dspi.c9
-rw-r--r--drivers/spi/spi.c22
2 files changed, 14 insertions, 17 deletions
diff --git a/drivers/spi/spi-fsl-dspi.c b/drivers/spi/spi-fsl-dspi.c
index 442cff71a0d2..9c3934efe2b1 100644
--- a/drivers/spi/spi-fsl-dspi.c
+++ b/drivers/spi/spi-fsl-dspi.c
@@ -185,6 +185,7 @@ struct fsl_dspi {
struct spi_transfer *cur_transfer;
struct spi_message *cur_msg;
struct chip_data *cur_chip;
+ size_t progress;
size_t len;
const void *tx;
void *rx;
@@ -658,7 +659,7 @@ static int dspi_rxtx(struct fsl_dspi *dspi)
u32 spi_tcr;
spi_take_timestamp_post(dspi->ctlr, dspi->cur_transfer,
- dspi->tx - dspi->bytes_per_word, !dspi->irq);
+ dspi->progress, !dspi->irq);
/* Get transfer counter (in number of SPI transfers). It was
* reset to 0 when transfer(s) were started.
@@ -667,6 +668,7 @@ static int dspi_rxtx(struct fsl_dspi *dspi)
spi_tcnt = SPI_TCR_GET_TCNT(spi_tcr);
/* Update total number of bytes that were transferred */
msg->actual_length += spi_tcnt * dspi->bytes_per_word;
+ dspi->progress += spi_tcnt;
trans_mode = dspi->devtype_data->trans_mode;
if (trans_mode == DSPI_EOQ_MODE)
@@ -679,7 +681,7 @@ static int dspi_rxtx(struct fsl_dspi *dspi)
return 0;
spi_take_timestamp_pre(dspi->ctlr, dspi->cur_transfer,
- dspi->tx, !dspi->irq);
+ dspi->progress, !dspi->irq);
if (trans_mode == DSPI_EOQ_MODE)
dspi_eoq_write(dspi);
@@ -768,6 +770,7 @@ static int dspi_transfer_one_message(struct spi_controller *ctlr,
dspi->rx = transfer->rx_buf;
dspi->rx_end = dspi->rx + transfer->len;
dspi->len = transfer->len;
+ dspi->progress = 0;
/* Validated transfer specific frame size (defaults applied) */
dspi->bits_per_word = transfer->bits_per_word;
if (transfer->bits_per_word <= 8)
@@ -789,7 +792,7 @@ static int dspi_transfer_one_message(struct spi_controller *ctlr,
SPI_CTARE_DTCP(1));
spi_take_timestamp_pre(dspi->ctlr, dspi->cur_transfer,
- dspi->tx, !dspi->irq);
+ dspi->progress, !dspi->irq);
trans_mode = dspi->devtype_data->trans_mode;
switch (trans_mode) {
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index 0d40953b463c..6b95cd957ba7 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -1499,8 +1499,7 @@ static void spi_pump_messages(struct kthread_work *work)
* advances its @tx buffer pointer monotonically.
* @ctlr: Pointer to the spi_controller structure of the driver
* @xfer: Pointer to the transfer being timestamped
- * @tx: Pointer to the current word within the xfer->tx_buf that the driver is
- * preparing to transmit right now.
+ * @progress: How many words (not bytes) have been transferred so far
* @irqs_off: If true, will disable IRQs and preemption for the duration of the
* transfer, for less jitter in time measurement. Only compatible
* with PIO drivers. If true, must follow up with
@@ -1510,21 +1509,19 @@ static void spi_pump_messages(struct kthread_work *work)
*/
void spi_take_timestamp_pre(struct spi_controller *ctlr,
struct spi_transfer *xfer,
- const void *tx, bool irqs_off)
+ size_t progress, bool irqs_off)
{
- u8 bytes_per_word = DIV_ROUND_UP(xfer->bits_per_word, 8);
-
if (!xfer->ptp_sts)
return;
if (xfer->timestamped_pre)
return;
- if (tx < (xfer->tx_buf + xfer->ptp_sts_word_pre * bytes_per_word))
+ if (progress < xfer->ptp_sts_word_pre)
return;
/* Capture the resolution of the timestamp */
- xfer->ptp_sts_word_pre = (tx - xfer->tx_buf) / bytes_per_word;
+ xfer->ptp_sts_word_pre = progress;
xfer->timestamped_pre = true;
@@ -1546,23 +1543,20 @@ EXPORT_SYMBOL_GPL(spi_take_timestamp_pre);
* timestamped.
* @ctlr: Pointer to the spi_controller structure of the driver
* @xfer: Pointer to the transfer being timestamped
- * @tx: Pointer to the current word within the xfer->tx_buf that the driver has
- * just transmitted.
+ * @progress: How many words (not bytes) have been transferred so far
* @irqs_off: If true, will re-enable IRQs and preemption for the local CPU.
*/
void spi_take_timestamp_post(struct spi_controller *ctlr,
struct spi_transfer *xfer,
- const void *tx, bool irqs_off)
+ size_t progress, bool irqs_off)
{
- u8 bytes_per_word = DIV_ROUND_UP(xfer->bits_per_word, 8);
-
if (!xfer->ptp_sts)
return;
if (xfer->timestamped_post)
return;
- if (tx < (xfer->tx_buf + xfer->ptp_sts_word_post * bytes_per_word))
+ if (progress < xfer->ptp_sts_word_post)
return;
ptp_read_system_postts(xfer->ptp_sts);
@@ -1573,7 +1567,7 @@ void spi_take_timestamp_post(struct spi_controller *ctlr,
}
/* Capture the resolution of the timestamp */
- xfer->ptp_sts_word_post = (tx - xfer->tx_buf) / bytes_per_word;
+ xfer->ptp_sts_word_post = progress;
xfer->timestamped_post = true;
}