[PATCH v6 13/14] spi: qup: Ensure done detection
From: Varadarajan Narayanan <hidden>
Date: 2017-07-28 06:54:11
Also in:
linux-arm-msm, linux-spi, lkml
Subsystem:
arm/qualcomm mailing list, spi subsystem, the rest · Maintainers:
Mark Brown, Linus Torvalds
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 <redacted> Signed-off-by: Abhishek Sahu <redacted> Signed-off-by: Varadarajan Narayanan <redacted> --- drivers/spi/spi-qup.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-)
diff --git a/drivers/spi/spi-qup.c b/drivers/spi/spi-qup.c
index 3c2c2c0..4c3c938 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);
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