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Subject[PATCH v6 02/14] spi: qup: Setup DMA mode correctly
Date
To operate in DMA mode, the buffer should be aligned and
the size of the transfer should be a multiple of block size
(for v1). And the no. of words being transferred should
be programmed in the count registers appropriately.

Signed-off-by: Andy Gross <andy.gross@linaro.org>
Signed-off-by: Varadarajan Narayanan <varada@codeaurora.org>
---
drivers/spi/spi-qup.c | 118 +++++++++++++++++++++++---------------------------
1 file changed, 55 insertions(+), 63 deletions(-)

diff --git a/drivers/spi/spi-qup.c b/drivers/spi/spi-qup.c
index c0d4def..abe799b 100644
--- a/drivers/spi/spi-qup.c
+++ b/drivers/spi/spi-qup.c
@@ -149,11 +149,18 @@ struct spi_qup {
int rx_bytes;
int qup_v1;

- int use_dma;
+ int mode;
struct dma_slave_config rx_conf;
struct dma_slave_config tx_conf;
};

+static inline bool spi_qup_is_dma_xfer(int mode)
+{
+ if (mode == QUP_IO_M_MODE_DMOV || mode == QUP_IO_M_MODE_BAM)
+ return true;
+
+ return false;
+}

static inline bool spi_qup_is_valid_state(struct spi_qup *controller)
{
@@ -424,7 +431,7 @@ static irqreturn_t spi_qup_qup_irq(int irq, void *dev_id)
error = -EIO;
}

- if (!controller->use_dma) {
+ if (!spi_qup_is_dma_xfer(controller->mode)) {
if (opflags & QUP_OP_IN_SERVICE_FLAG)
spi_qup_fifo_read(controller, xfer);

@@ -443,34 +450,11 @@ static irqreturn_t spi_qup_qup_irq(int irq, void *dev_id)
return IRQ_HANDLED;
}

-static u32
-spi_qup_get_mode(struct spi_master *master, struct spi_transfer *xfer)
-{
- struct spi_qup *qup = spi_master_get_devdata(master);
- u32 mode;
-
- qup->w_size = 4;
-
- if (xfer->bits_per_word <= 8)
- qup->w_size = 1;
- else if (xfer->bits_per_word <= 16)
- qup->w_size = 2;
-
- qup->n_words = xfer->len / qup->w_size;
-
- if (qup->n_words <= (qup->in_fifo_sz / sizeof(u32)))
- mode = QUP_IO_M_MODE_FIFO;
- else
- mode = QUP_IO_M_MODE_BLOCK;
-
- return mode;
-}
-
/* set clock freq ... bits per word */
static int spi_qup_io_config(struct spi_device *spi, struct spi_transfer *xfer)
{
struct spi_qup *controller = spi_master_get_devdata(spi->master);
- u32 config, iomode, mode, control;
+ u32 config, iomode, control;
int ret, n_words;

if (spi->mode & SPI_LOOP && xfer->len > controller->in_fifo_sz) {
@@ -491,25 +475,30 @@ static int spi_qup_io_config(struct spi_device *spi, struct spi_transfer *xfer)
return -EIO;
}

- mode = spi_qup_get_mode(spi->master, xfer);
+ controller->w_size = DIV_ROUND_UP(xfer->bits_per_word, 8);
+ controller->n_words = xfer->len / controller->w_size;
n_words = controller->n_words;

- if (mode == QUP_IO_M_MODE_FIFO) {
+ if (n_words <= (controller->in_fifo_sz / sizeof(u32))) {
+
+ controller->mode = QUP_IO_M_MODE_FIFO;
+
writel_relaxed(n_words, controller->base + QUP_MX_READ_CNT);
writel_relaxed(n_words, controller->base + QUP_MX_WRITE_CNT);
/* must be zero for FIFO */
writel_relaxed(0, controller->base + QUP_MX_INPUT_CNT);
writel_relaxed(0, controller->base + QUP_MX_OUTPUT_CNT);
- } else if (!controller->use_dma) {
+ } else if (spi->master->can_dma &&
+ spi->master->can_dma(spi->master, spi, xfer) &&
+ spi->master->cur_msg_mapped) {
+
+ controller->mode = QUP_IO_M_MODE_BAM;
+
writel_relaxed(n_words, controller->base + QUP_MX_INPUT_CNT);
writel_relaxed(n_words, controller->base + QUP_MX_OUTPUT_CNT);
/* must be zero for BLOCK and BAM */
writel_relaxed(0, controller->base + QUP_MX_READ_CNT);
writel_relaxed(0, controller->base + QUP_MX_WRITE_CNT);
- } else {
- mode = QUP_IO_M_MODE_BAM;
- writel_relaxed(0, controller->base + QUP_MX_READ_CNT);
- writel_relaxed(0, controller->base + QUP_MX_WRITE_CNT);

if (!controller->qup_v1) {
void __iomem *input_cnt;
@@ -528,19 +517,28 @@ static int spi_qup_io_config(struct spi_device *spi, struct spi_transfer *xfer)

writel_relaxed(0, controller->base + QUP_MX_OUTPUT_CNT);
}
+ } else {
+
+ controller->mode = QUP_IO_M_MODE_BLOCK;
+
+ writel_relaxed(n_words, controller->base + QUP_MX_INPUT_CNT);
+ writel_relaxed(n_words, controller->base + QUP_MX_OUTPUT_CNT);
+ /* must be zero for BLOCK and BAM */
+ writel_relaxed(0, controller->base + QUP_MX_READ_CNT);
+ writel_relaxed(0, controller->base + QUP_MX_WRITE_CNT);
}

iomode = readl_relaxed(controller->base + QUP_IO_M_MODES);
/* Set input and output transfer mode */
iomode &= ~(QUP_IO_M_INPUT_MODE_MASK | QUP_IO_M_OUTPUT_MODE_MASK);

- if (!controller->use_dma)
+ if (!spi_qup_is_dma_xfer(controller->mode))
iomode &= ~(QUP_IO_M_PACK_EN | QUP_IO_M_UNPACK_EN);
else
iomode |= QUP_IO_M_PACK_EN | QUP_IO_M_UNPACK_EN;

- iomode |= (mode << QUP_IO_M_OUTPUT_MODE_MASK_SHIFT);
- iomode |= (mode << QUP_IO_M_INPUT_MODE_MASK_SHIFT);
+ iomode |= (controller->mode << QUP_IO_M_OUTPUT_MODE_MASK_SHIFT);
+ iomode |= (controller->mode << QUP_IO_M_INPUT_MODE_MASK_SHIFT);

writel_relaxed(iomode, controller->base + QUP_IO_M_MODES);

@@ -581,7 +579,7 @@ static int spi_qup_io_config(struct spi_device *spi, struct spi_transfer *xfer)
config |= xfer->bits_per_word - 1;
config |= QUP_CONFIG_SPI_MODE;

- if (controller->use_dma) {
+ if (spi_qup_is_dma_xfer(controller->mode)) {
if (!xfer->tx_buf)
config |= QUP_CONFIG_NO_OUTPUT;
if (!xfer->rx_buf)
@@ -599,7 +597,7 @@ static int spi_qup_io_config(struct spi_device *spi, struct spi_transfer *xfer)
* status change in BAM mode
*/

- if (mode == QUP_IO_M_MODE_BAM)
+ if (spi_qup_is_dma_xfer(controller->mode))
mask = QUP_OP_IN_SERVICE_FLAG | QUP_OP_OUT_SERVICE_FLAG;

writel_relaxed(mask, controller->base + QUP_OPERATIONAL_MASK);
@@ -633,7 +631,7 @@ static int spi_qup_transfer_one(struct spi_master *master,
controller->tx_bytes = 0;
spin_unlock_irqrestore(&controller->lock, flags);

- if (controller->use_dma)
+ if (spi_qup_is_dma_xfer(controller->mode))
ret = spi_qup_do_dma(master, xfer);
else
ret = spi_qup_do_pio(master, xfer);
@@ -641,14 +639,6 @@ static int spi_qup_transfer_one(struct spi_master *master,
if (ret)
goto exit;

- if (spi_qup_set_state(controller, QUP_STATE_RUN)) {
- dev_warn(controller->dev, "cannot set EXECUTE state\n");
- goto exit;
- }
-
- if (!wait_for_completion_timeout(&controller->done, timeout))
- ret = -ETIMEDOUT;
-
exit:
spi_qup_set_state(controller, QUP_STATE_RESET);
spin_lock_irqsave(&controller->lock, flags);
@@ -657,7 +647,7 @@ static int spi_qup_transfer_one(struct spi_master *master,
ret = controller->error;
spin_unlock_irqrestore(&controller->lock, flags);

- if (ret && controller->use_dma)
+ if (ret && spi_qup_is_dma_xfer(controller->mode))
spi_qup_dma_terminate(master, xfer);

return ret;
@@ -668,26 +658,28 @@ static bool spi_qup_can_dma(struct spi_master *master, struct spi_device *spi,
{
struct spi_qup *qup = spi_master_get_devdata(master);
size_t dma_align = dma_get_cache_alignment();
- u32 mode;
-
- qup->use_dma = 0;
+ int n_words;

- if (xfer->rx_buf && (xfer->len % qup->in_blk_sz ||
- IS_ERR_OR_NULL(master->dma_rx) ||
- !IS_ALIGNED((size_t)xfer->rx_buf, dma_align)))
- return false;
+ if (xfer->rx_buf) {
+ if (!IS_ALIGNED((size_t)xfer->rx_buf, dma_align) ||
+ IS_ERR_OR_NULL(master->dma_rx))
+ return false;
+ if (qup->qup_v1 && (xfer->len % qup->in_blk_sz))
+ return false;
+ }

- if (xfer->tx_buf && (xfer->len % qup->out_blk_sz ||
- IS_ERR_OR_NULL(master->dma_tx) ||
- !IS_ALIGNED((size_t)xfer->tx_buf, dma_align)))
- return false;
+ if (xfer->tx_buf) {
+ if (!IS_ALIGNED((size_t)xfer->tx_buf, dma_align) ||
+ IS_ERR_OR_NULL(master->dma_tx))
+ return false;
+ if (qup->qup_v1 && (xfer->len % qup->out_blk_sz))
+ return false;
+ }

- mode = spi_qup_get_mode(master, xfer);
- if (mode == QUP_IO_M_MODE_FIFO)
+ n_words = xfer->len / DIV_ROUND_UP(xfer->bits_per_word, 8);
+ if (n_words <= (qup->in_fifo_sz / sizeof(u32)))
return false;

- qup->use_dma = 1;
-
return true;
}

--
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation
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