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authorVaradarajan Narayanan <varada@codeaurora.org>2017-07-28 09:53:00 +0300
committerMark Brown <broonie@kernel.org>2017-08-08 14:15:50 +0300
commitcd595b99af24b8efa4a6a8889ad65f4d270fd644 (patch)
tree65f2b3f6ce01b103f492055d6607351789bff5fa /drivers/spi
parent5884e17ef3cb3dac2e83e466246cf033bfba0e2f (diff)
downloadlinux-cd595b99af24b8efa4a6a8889ad65f4d270fd644.tar.xz
spi: qup: Ensure done detection
This patch fixes an issue where a SPI transaction has completed, but the done condition is missed. This occurs because at the time of interrupt the MAX_INPUT_DONE_FLAG is not asserted. However, in the process of reading blocks of data from the FIFO, the last portion of data comes in. The opflags read at the beginning of the irq handler no longer matches the current opflag state. To get around this condition, the block read function should update the opflags so that done detection is correct after the return. Signed-off-by: Andy Gross <agross@codeaurora.org> Signed-off-by: Abhishek Sahu <absahu@codeaurora.org> Signed-off-by: Varadarajan Narayanan <varada@codeaurora.org> Signed-off-by: Mark Brown <broonie@kernel.org>
Diffstat (limited to 'drivers/spi')
-rw-r--r--drivers/spi/spi-qup.c12
1 files changed, 7 insertions, 5 deletions
diff --git a/drivers/spi/spi-qup.c b/drivers/spi/spi-qup.c
index 3c2c2c0ed9ab..4c3c938360f4 100644
--- a/drivers/spi/spi-qup.c
+++ b/drivers/spi/spi-qup.c
@@ -266,7 +266,7 @@ static void spi_qup_read_from_fifo(struct spi_qup *controller, u32 num_words)
}
}
-static void spi_qup_read(struct spi_qup *controller)
+static void spi_qup_read(struct spi_qup *controller, u32 *opflags)
{
u32 remainder, words_per_block, num_words;
bool is_block_mode = controller->mode == QUP_IO_M_MODE_BLOCK;
@@ -305,10 +305,12 @@ static void spi_qup_read(struct spi_qup *controller)
/*
* Due to extra stickiness of the QUP_OP_IN_SERVICE_FLAG during block
- * mode reads, it has to be cleared again at the very end
+ * reads, it has to be cleared again at the very end. However, be sure
+ * to refresh opflags value because MAX_INPUT_DONE_FLAG may now be
+ * present and this is used to determine if transaction is complete
*/
- if (is_block_mode && spi_qup_is_flag_set(controller,
- QUP_OP_MAX_INPUT_DONE_FLAG))
+ *opflags = readl_relaxed(controller->base + QUP_OPERATIONAL);
+ if (is_block_mode && *opflags & QUP_OP_MAX_INPUT_DONE_FLAG)
writel_relaxed(QUP_OP_IN_SERVICE_FLAG,
controller->base + QUP_OPERATIONAL);
@@ -613,7 +615,7 @@ static irqreturn_t spi_qup_qup_irq(int irq, void *dev_id)
writel_relaxed(opflags, controller->base + QUP_OPERATIONAL);
} else {
if (opflags & QUP_OP_IN_SERVICE_FLAG)
- spi_qup_read(controller);
+ spi_qup_read(controller, &opflags);
if (opflags & QUP_OP_OUT_SERVICE_FLAG)
spi_qup_write(controller);