From 5884e17ef3cb3dac2e83e466246cf033bfba0e2f Mon Sep 17 00:00:00 2001 From: Varadarajan Narayanan Date: Fri, 28 Jul 2017 12:22:59 +0530 Subject: 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 Signed-off-by: Varadarajan Narayanan Signed-off-by: Mark Brown --- drivers/spi/spi-qup.c | 92 ++++++++++++++++++++++++++++++++++++--------------- 1 file changed, 66 insertions(+), 26 deletions(-) diff --git a/drivers/spi/spi-qup.c b/drivers/spi/spi-qup.c index 1af3b41ac12d..3c2c2c0ed9ab 100644 --- a/drivers/spi/spi-qup.c +++ b/drivers/spi/spi-qup.c @@ -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 (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; - if (xfer->rx_buf) { - ret = spi_qup_prep_sg(master, xfer->rx_sg.sgl, - xfer->rx_sg.nents, DMA_DEV_TO_MEM, - rx_done); + 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; + + 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)) + ; - if (!wait_for_completion_timeout(&qup->done, timeout)) - return -ETIMEDOUT; + } while (rx_sgl || tx_sgl); return 0; } -- cgit