diff options
Diffstat (limited to 'drivers/spi')
| -rw-r--r-- | drivers/spi/davinci_spi.c | 52 |
1 files changed, 21 insertions, 31 deletions
diff --git a/drivers/spi/davinci_spi.c b/drivers/spi/davinci_spi.c index a5f03dd..f512939 100644 --- a/drivers/spi/davinci_spi.c +++ b/drivers/spi/davinci_spi.c @@ -38,8 +38,6 @@ #define CS_DEFAULT 0xFF -#define SPI_BUFSIZ (SMP_CACHE_BYTES + 1) - #define SPIFMT_PHASE_MASK BIT(16) #define SPIFMT_POLARITY_MASK BIT(17) #define SPIFMT_DISTIMER_MASK BIT(18) @@ -140,7 +138,6 @@ struct davinci_spi { const void *tx; void *rx; - u8 *tmp_buf; int rcount; int wcount; struct davinci_spi_dma dma_channels; @@ -718,7 +715,7 @@ static int davinci_spi_bufs_dma(struct spi_device *spi, struct spi_transfer *t) { struct davinci_spi *davinci_spi; int int_status = 0; - int count, temp_count; + int count; struct davinci_spi_dma *davinci_spi_dma; int data_type, ret; unsigned long tx_reg, rx_reg; @@ -750,6 +747,18 @@ static int davinci_spi_bufs_dma(struct spi_device *spi, struct spi_transfer *t) /* Enable SPI */ set_io_bits(davinci_spi->base + SPIGCR1, SPIGCR1_SPIENA_MASK); + /* + * Transmit DMA setup + * + * If there is transmit data, map the transmit buffer, set it as the + * source of data and set the source B index to data size. + * If there is no transmit data, set the transmit register as the + * source of data, and set the source B index to zero. + * + * The destination is always the transmit register itself. And the + * destination never increments. + */ + if (t->tx_buf) { t->tx_dma = dma_map_single(&spi->dev, (void *)t->tx_buf, count, DMA_TO_DEVICE); @@ -758,25 +767,15 @@ static int davinci_spi_bufs_dma(struct spi_device *spi, struct spi_transfer *t) " TX buffer\n", count); return -ENOMEM; } - temp_count = count; - } else { - /* We need TX clocking for RX transaction */ - t->tx_dma = dma_map_single(&spi->dev, - (void *)davinci_spi->tmp_buf, count + 1, - DMA_TO_DEVICE); - if (dma_mapping_error(&spi->dev, t->tx_dma)) { - dev_dbg(sdev, "Unable to DMA map a %d bytes" - " TX tmp buffer\n", count); - return -ENOMEM; - } - temp_count = count + 1; } edma_set_transfer_params(davinci_spi_dma->dma_tx_channel, - data_type, temp_count, 1, 0, ASYNC); + data_type, count, 1, 0, ASYNC); edma_set_dest(davinci_spi_dma->dma_tx_channel, tx_reg, INCR, W8BIT); - edma_set_src(davinci_spi_dma->dma_tx_channel, t->tx_dma, INCR, W8BIT); - edma_set_src_index(davinci_spi_dma->dma_tx_channel, data_type, 0); + edma_set_src(davinci_spi_dma->dma_tx_channel, + t->tx_buf ? t->tx_dma : tx_reg, INCR, W8BIT); + edma_set_src_index(davinci_spi_dma->dma_tx_channel, + t->tx_buf ? data_type : 0, 0); edma_set_dest_index(davinci_spi_dma->dma_tx_channel, 0, 0); if (t->rx_buf) { @@ -818,7 +817,8 @@ static int davinci_spi_bufs_dma(struct spi_device *spi, struct spi_transfer *t) wait_for_completion_interruptible( &davinci_spi_dma->dma_rx_completion); - dma_unmap_single(NULL, t->tx_dma, temp_count, DMA_TO_DEVICE); + if (t->tx_buf) + dma_unmap_single(NULL, t->tx_dma, count, DMA_TO_DEVICE); if (t->rx_buf) dma_unmap_single(NULL, t->rx_dma, count, DMA_FROM_DEVICE); @@ -906,17 +906,10 @@ static int davinci_spi_probe(struct platform_device *pdev) if (ret) goto unmap_io; - /* Allocate tmp_buf for tx_buf */ - davinci_spi->tmp_buf = kzalloc(SPI_BUFSIZ, GFP_KERNEL); - if (davinci_spi->tmp_buf == NULL) { - ret = -ENOMEM; - goto irq_free; - } - davinci_spi->bitbang.master = spi_master_get(master); if (davinci_spi->bitbang.master == NULL) { ret = -ENODEV; - goto free_tmp_buf; + goto irq_free; } davinci_spi->clk = clk_get(&pdev->dev, NULL); @@ -1027,8 +1020,6 @@ free_clk: clk_put(davinci_spi->clk); put_master: spi_master_put(master); -free_tmp_buf: - kfree(davinci_spi->tmp_buf); irq_free: free_irq(davinci_spi->irq, davinci_spi); unmap_io: @@ -1063,7 +1054,6 @@ static int __exit davinci_spi_remove(struct platform_device *pdev) clk_disable(davinci_spi->clk); clk_put(davinci_spi->clk); spi_master_put(master); - kfree(davinci_spi->tmp_buf); free_irq(davinci_spi->irq, davinci_spi); iounmap(davinci_spi->base); release_mem_region(davinci_spi->pbase, davinci_spi->region_size); |