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spi: qup: allow multiple DMA transactions per spi xfer 

Much like the block mode changes, we are breaking up DMA transactions
into 64K chunks so we can reset the QUP engine.

Signed-off-by: Matthew McClintock <mmcclint@codeaurora.org>
Signed-off-by: Varadarajan Narayanan <varada@codeaurora.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Varadarajan Narayanan 2017-07-28 12:22:59 +05:30 committed by Mark Brown
parent a841b24e62
commit 5884e17ef3
1 changed files with 66 additions and 26 deletions
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92
drivers/spi/spi-qup.c
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@ -418,12 +418,35 @@ static void spi_qup_dma_terminate(struct spi_master *master,
dmaengine_terminate_all(master->dma_rx);
}
static u32 spi_qup_sgl_get_nents_len(struct scatterlist *sgl, u32 max,
u32 *nents)
{
struct scatterlist *sg;
u32 total = 0;
*nents = 0;
for (sg = sgl; sg; sg = sg_next(sg)) {
unsigned int len = sg_dma_len(sg);
/* check for overflow as well as limit */
if (((total + len) < total) || ((total + len) > max))
break;
total += len;
(*nents)++;
}
return total;
}
static int spi_qup_do_dma(struct spi_device *spi, struct spi_transfer *xfer,
unsigned long timeout)
{
dma_async_tx_callback rx_done = NULL, tx_done = NULL;
struct spi_master *master = spi->master;
struct spi_qup *qup = spi_master_get_devdata(master);
struct scatterlist *tx_sgl, *rx_sgl;
int ret;
if (xfer->rx_buf)
@ -431,40 +454,57 @@ static int spi_qup_do_dma(struct spi_device *spi, struct spi_transfer *xfer,
else if (xfer->tx_buf)
tx_done = spi_qup_dma_done;
ret = spi_qup_io_config(spi, xfer);
if (ret)
return ret;
rx_sgl = xfer->rx_sg.sgl;
tx_sgl = xfer->tx_sg.sgl;
/* before issuing the descriptors, set the QUP to run */
ret = spi_qup_set_state(qup, QUP_STATE_RUN);
if (ret) {
dev_warn(qup->dev, "%s(%d): cannot set RUN state\n",
__func__, __LINE__);
return ret;
}
do {
u32 rx_nents, tx_nents;
if (xfer->rx_buf) {
ret = spi_qup_prep_sg(master, xfer->rx_sg.sgl,
xfer->rx_sg.nents, DMA_DEV_TO_MEM,
rx_done);
if (rx_sgl)
qup->n_words = spi_qup_sgl_get_nents_len(rx_sgl,
SPI_MAX_XFER, &rx_nents) / qup->w_size;
if (tx_sgl)
qup->n_words = spi_qup_sgl_get_nents_len(tx_sgl,
SPI_MAX_XFER, &tx_nents) / qup->w_size;
if (!qup->n_words)
return -EIO;
ret = spi_qup_io_config(spi, xfer);
if (ret)
return ret;
dma_async_issue_pending(master->dma_rx);
}
if (xfer->tx_buf) {
ret = spi_qup_prep_sg(master, xfer->tx_sg.sgl,
xfer->tx_sg.nents, DMA_MEM_TO_DEV,
tx_done);
if (ret)
/* before issuing the descriptors, set the QUP to run */
ret = spi_qup_set_state(qup, QUP_STATE_RUN);
if (ret) {
dev_warn(qup->dev, "cannot set RUN state\n");
return ret;
}
if (rx_sgl) {
ret = spi_qup_prep_sg(master, rx_sgl, rx_nents,
DMA_DEV_TO_MEM, rx_done);
if (ret)
return ret;
dma_async_issue_pending(master->dma_rx);
}
dma_async_issue_pending(master->dma_tx);
}
if (tx_sgl) {
ret = spi_qup_prep_sg(master, tx_sgl, tx_nents,
DMA_MEM_TO_DEV, tx_done);
if (ret)
return ret;
if (!wait_for_completion_timeout(&qup->done, timeout))
return -ETIMEDOUT;
dma_async_issue_pending(master->dma_tx);
}
if (!wait_for_completion_timeout(&qup->done, timeout))
return -ETIMEDOUT;
for (; rx_sgl && rx_nents--; rx_sgl = sg_next(rx_sgl))
;
for (; tx_sgl && tx_nents--; tx_sgl = sg_next(tx_sgl))
;
} while (rx_sgl || tx_sgl);
return 0;
}