From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vladimir Oltean Subject: [PATCH v3 4/7] spi: spi-fsl-dspi: Fix bits-per-word acceleration in DMA mode Date: Tue, 10 Mar 2020 14:55:39 +0200 Message-ID: <20200310125542.5939-5-olteanv@gmail.com> References: <20200310125542.5939-1-olteanv@gmail.com> Cc: linux-spi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, shawnguo-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, robh+dt-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, mark.rutland-5wv7dgnIgG8@public.gmane.org, devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, eha-/iRVSOupHO4@public.gmane.org, angelo-BIYBQhTR83Y@public.gmane.org, andrew.smirnov-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, gustavo-L1vi/lXTdts+Va1GwOuvDg@public.gmane.org, weic-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org, mhosny-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org, michael-QKn5cuLxLXY@public.gmane.org, peng.ma-3arQi8VN3Tc@public.gmane.org To: broonie-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org Return-path: In-Reply-To: <20200310125542.5939-1-olteanv-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-spi.vger.kernel.org From: Vladimir Oltean In DMA mode, dspi_setup_accel does not get called, which results in the dspi->oper_word_size variable (which is used by dspi_dma_xfer) to not be initialized properly. Because oper_word_size is zero, a few calculations end up being incorrect, and the DMA transfer eventually times out instead of sending anything on the wire. Set up native transfers (or 8-on-16 acceleration) using dspi_setup_accel for DMA mode too. Also take the opportunity and simplify the DMA buffer handling a little bit. Fixes: 6c1c26ecd9a3 ("spi: spi-fsl-dspi: Accelerate transfers using larger word size if possible") Signed-off-by: Vladimir Oltean --- Changes in v3: Pretty much re-did the patch. Before, dspi_setup_accel was called just once at the beginning of dspi_dma_xfer. Now it is called in the while loop. Everything else is just refactoring that follows along. Changes in v2: None. drivers/spi/spi-fsl-dspi.c | 7 +++++-- drivers/spi/spi-fsl-dspi.c | 83 +++++++++++++++++++------------------- 1 file changed, 42 insertions(+), 41 deletions(-) diff --git a/drivers/spi/spi-fsl-dspi.c b/drivers/spi/spi-fsl-dspi.c index c59b68592283..8f5d18dc78d5 100644 --- a/drivers/spi/spi-fsl-dspi.c +++ b/drivers/spi/spi-fsl-dspi.c @@ -119,7 +119,6 @@ struct fsl_dspi_devtype_data { enum dspi_trans_mode trans_mode; u8 max_clock_factor; int fifo_size; - int dma_bufsize; }; enum { @@ -138,7 +137,6 @@ static const struct fsl_dspi_devtype_data devtype_data[] = { [VF610] = { .trans_mode = DSPI_DMA_MODE, .max_clock_factor = 2, - .dma_bufsize = 4096, .fifo_size = 4, }, [LS1021A] = { @@ -167,19 +165,16 @@ static const struct fsl_dspi_devtype_data devtype_data[] = { }, [LS2080A] = { .trans_mode = DSPI_DMA_MODE, - .dma_bufsize = 8, .max_clock_factor = 8, .fifo_size = 4, }, [LS2085A] = { .trans_mode = DSPI_DMA_MODE, - .dma_bufsize = 8, .max_clock_factor = 8, .fifo_size = 4, }, [LX2160A] = { .trans_mode = DSPI_DMA_MODE, - .dma_bufsize = 8, .max_clock_factor = 8, .fifo_size = 4, }, @@ -191,9 +186,6 @@ static const struct fsl_dspi_devtype_data devtype_data[] = { }; struct fsl_dspi_dma { - /* Length of transfer in words of dspi->fifo_size */ - u32 curr_xfer_len; - u32 *tx_dma_buf; struct dma_chan *chan_tx; dma_addr_t tx_dma_phys; @@ -352,7 +344,7 @@ static void dspi_rx_dma_callback(void *arg) int i; if (dspi->rx) { - for (i = 0; i < dma->curr_xfer_len; i++) + for (i = 0; i < dspi->words_in_flight; i++) dspi_push_rx(dspi, dspi->dma->rx_dma_buf[i]); } @@ -366,12 +358,12 @@ static int dspi_next_xfer_dma_submit(struct fsl_dspi *dspi) int time_left; int i; - for (i = 0; i < dma->curr_xfer_len; i++) + for (i = 0; i < dspi->words_in_flight; i++) dspi->dma->tx_dma_buf[i] = dspi_pop_tx_pushr(dspi); dma->tx_desc = dmaengine_prep_slave_single(dma->chan_tx, dma->tx_dma_phys, - dma->curr_xfer_len * + dspi->words_in_flight * DMA_SLAVE_BUSWIDTH_4_BYTES, DMA_MEM_TO_DEV, DMA_PREP_INTERRUPT | DMA_CTRL_ACK); @@ -389,7 +381,7 @@ static int dspi_next_xfer_dma_submit(struct fsl_dspi *dspi) dma->rx_desc = dmaengine_prep_slave_single(dma->chan_rx, dma->rx_dma_phys, - dma->curr_xfer_len * + dspi->words_in_flight * DMA_SLAVE_BUSWIDTH_4_BYTES, DMA_DEV_TO_MEM, DMA_PREP_INTERRUPT | DMA_CTRL_ACK); @@ -437,46 +429,56 @@ static int dspi_next_xfer_dma_submit(struct fsl_dspi *dspi) return 0; } +static void dspi_setup_accel(struct fsl_dspi *dspi); + static int dspi_dma_xfer(struct fsl_dspi *dspi) { struct spi_message *message = dspi->cur_msg; struct device *dev = &dspi->pdev->dev; - struct fsl_dspi_dma *dma = dspi->dma; - int curr_remaining_bytes; - int bytes_per_buffer; + int bytes_in_flight = dspi->len; + int chunk_size; int ret = 0; - curr_remaining_bytes = dspi->len; - bytes_per_buffer = dspi->devtype_data->dma_bufsize / - dspi->devtype_data->fifo_size; - while (curr_remaining_bytes) { + /* + * dspi->len gets decremented by dspi_pop_tx_pushr in + * dspi_next_xfer_dma_submit + */ + while (dspi->len) { + /* Figure out operational bits-per-word for this chunk */ + dspi_setup_accel(dspi); + + /* + * If the 16-bit TXDATA of the PUSHR is underutilized, then + * each DMA buffer will be able to hold only up to fifo_size + * useful bytes. + */ + if (dspi->oper_word_size == 1) + chunk_size = dspi->devtype_data->fifo_size; + else + chunk_size = dspi->devtype_data->fifo_size * 2; + /* Check if current transfer fits the DMA buffer */ - dma->curr_xfer_len = curr_remaining_bytes / - dspi->oper_word_size; - if (dma->curr_xfer_len > bytes_per_buffer) - dma->curr_xfer_len = bytes_per_buffer; + bytes_in_flight = dspi->len; + if (bytes_in_flight > chunk_size) + bytes_in_flight = chunk_size; + + dspi->words_in_flight = bytes_in_flight / dspi->oper_word_size; ret = dspi_next_xfer_dma_submit(dspi); if (ret) { dev_err(dev, "DMA transfer failed\n"); - goto exit; - - } else { - const int len = dma->curr_xfer_len * - dspi->oper_word_size; - curr_remaining_bytes -= len; - message->actual_length += len; - if (curr_remaining_bytes < 0) - curr_remaining_bytes = 0; + break; } + + message->actual_length += bytes_in_flight; } -exit: return ret; } static int dspi_request_dma(struct fsl_dspi *dspi, phys_addr_t phy_addr) { + int dma_bufsize = dspi->devtype_data->fifo_size * 2; struct device *dev = &dspi->pdev->dev; struct dma_slave_config cfg; struct fsl_dspi_dma *dma; @@ -500,14 +502,14 @@ static int dspi_request_dma(struct fsl_dspi *dspi, phys_addr_t phy_addr) goto err_tx_channel; } - dma->tx_dma_buf = dma_alloc_coherent(dev, dspi->devtype_data->dma_bufsize, + dma->tx_dma_buf = dma_alloc_coherent(dev, dma_bufsize, &dma->tx_dma_phys, GFP_KERNEL); if (!dma->tx_dma_buf) { ret = -ENOMEM; goto err_tx_dma_buf; } - dma->rx_dma_buf = dma_alloc_coherent(dev, dspi->devtype_data->dma_bufsize, + dma->rx_dma_buf = dma_alloc_coherent(dev, dma_bufsize, &dma->rx_dma_phys, GFP_KERNEL); if (!dma->rx_dma_buf) { ret = -ENOMEM; @@ -544,10 +546,10 @@ static int dspi_request_dma(struct fsl_dspi *dspi, phys_addr_t phy_addr) return 0; err_slave_config: - dma_free_coherent(dev, dspi->devtype_data->dma_bufsize, + dma_free_coherent(dev, dma_bufsize, dma->rx_dma_buf, dma->rx_dma_phys); err_rx_dma_buf: - dma_free_coherent(dev, dspi->devtype_data->dma_bufsize, + dma_free_coherent(dev, dma_bufsize, dma->tx_dma_buf, dma->tx_dma_phys); err_tx_dma_buf: dma_release_channel(dma->chan_tx); @@ -562,6 +564,7 @@ static int dspi_request_dma(struct fsl_dspi *dspi, phys_addr_t phy_addr) static void dspi_release_dma(struct fsl_dspi *dspi) { + int dma_bufsize = dspi->devtype_data->fifo_size * 2; struct fsl_dspi_dma *dma = dspi->dma; struct device *dev = &dspi->pdev->dev; @@ -570,15 +573,13 @@ static void dspi_release_dma(struct fsl_dspi *dspi) if (dma->chan_tx) { dma_unmap_single(dev, dma->tx_dma_phys, - dspi->devtype_data->dma_bufsize, - DMA_TO_DEVICE); + dma_bufsize, DMA_TO_DEVICE); dma_release_channel(dma->chan_tx); } if (dma->chan_rx) { dma_unmap_single(dev, dma->rx_dma_phys, - dspi->devtype_data->dma_bufsize, - DMA_FROM_DEVICE); + dma_bufsize, DMA_FROM_DEVICE); dma_release_channel(dma->chan_rx); } } -- 2.17.1