From: Brian Niebuhr Date: Tue, 5 Oct 2010 06:08:41 +0000 (+0530) Subject: spi: davinci: handle DMA completion errors correctly X-Git-Tag: v2.6.38-rc1~454^2~6^2~10 X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=9b189fd7584a1d8c68334dd1bc47b363877b314e;p=karo-tx-linux.git spi: davinci: handle DMA completion errors correctly Do not simply clean the DMA channel on a DMA completion error. Instead, use wcount and rcount members of davinci_spi to detecion non-completion of DMA and signal EIO to the application. Signed-off-by: Brian Niebuhr Tested-By: Michael Williamson Signed-off-by: Sekhar Nori --- diff --git a/drivers/spi/davinci_spi.c b/drivers/spi/davinci_spi.c index 975c2a228d0a..a47947da17a3 100644 --- a/drivers/spi/davinci_spi.c +++ b/drivers/spi/davinci_spi.c @@ -388,24 +388,26 @@ static int davinci_spi_setup_transfer(struct spi_device *spi, static void davinci_spi_dma_rx_callback(unsigned lch, u16 ch_status, void *data) { - struct davinci_spi_dma *davinci_spi_dma = data; + struct davinci_spi *davinci_spi = data; + struct davinci_spi_dma *davinci_spi_dma = &davinci_spi->dma_channels; + + edma_stop(davinci_spi_dma->dma_rx_channel); if (ch_status == DMA_COMPLETE) - edma_stop(davinci_spi_dma->dma_rx_channel); - else - edma_clean_channel(davinci_spi_dma->dma_rx_channel); + davinci_spi->rcount = 0; complete(&davinci_spi_dma->dma_rx_completion); } static void davinci_spi_dma_tx_callback(unsigned lch, u16 ch_status, void *data) { - struct davinci_spi_dma *davinci_spi_dma = data; + struct davinci_spi *davinci_spi = data; + struct davinci_spi_dma *davinci_spi_dma = &davinci_spi->dma_channels; + + edma_stop(davinci_spi_dma->dma_tx_channel); if (ch_status == DMA_COMPLETE) - edma_stop(davinci_spi_dma->dma_tx_channel); - else - edma_clean_channel(davinci_spi_dma->dma_tx_channel); + davinci_spi->wcount = 0; complete(&davinci_spi_dma->dma_tx_completion); } @@ -632,7 +634,6 @@ 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; unsigned rx_buf_count; struct davinci_spi_dma *davinci_spi_dma; int data_type, ret; @@ -648,20 +649,20 @@ static int davinci_spi_bufs_dma(struct spi_device *spi, struct spi_transfer *t) davinci_spi_dma = &davinci_spi->dma_channels; + /* convert len to words based on bits_per_word */ + data_type = davinci_spi->bytes_per_word[spi->chip_select]; + tx_reg = (unsigned long)davinci_spi->pbase + SPIDAT1; rx_reg = (unsigned long)davinci_spi->pbase + SPIBUF; davinci_spi->tx = t->tx_buf; davinci_spi->rx = t->rx_buf; - - /* convert len to words based on bits_per_word */ - data_type = davinci_spi->bytes_per_word[spi->chip_select]; + davinci_spi->wcount = t->len / data_type; + davinci_spi->rcount = davinci_spi->wcount; init_completion(&davinci_spi_dma->dma_rx_completion); init_completion(&davinci_spi_dma->dma_tx_completion); - count = t->len / data_type; /* the number of elements */ - /* disable all interrupts for dma transfers */ clear_io_bits(davinci_spi->base + SPIINT, SPIINT_MASKALL); /* Enable SPI */ @@ -680,18 +681,18 @@ static int davinci_spi_bufs_dma(struct spi_device *spi, struct spi_transfer *t) */ if (t->tx_buf) { - t->tx_dma = dma_map_single(&spi->dev, (void *)t->tx_buf, count, - DMA_TO_DEVICE); + t->tx_dma = dma_map_single(&spi->dev, (void *)t->tx_buf, + davinci_spi->wcount, DMA_TO_DEVICE); if (dma_mapping_error(&spi->dev, t->tx_dma)) { - dev_dbg(sdev, "Unable to DMA map a %d bytes" - " TX buffer\n", count); + dev_dbg(sdev, "Unable to DMA map %d bytes TX buffer\n", + davinci_spi->wcount); return -ENOMEM; } } param.opt = TCINTEN | EDMA_TCC(davinci_spi_dma->dma_tx_channel); param.src = t->tx_buf ? t->tx_dma : tx_reg; - param.a_b_cnt = count << 16 | data_type; + param.a_b_cnt = davinci_spi->wcount << 16 | data_type; param.dst = tx_reg; param.src_dst_bidx = t->tx_buf ? data_type : 0; param.link_bcntrld = 0xffff; @@ -715,7 +716,7 @@ static int davinci_spi_bufs_dma(struct spi_device *spi, struct spi_transfer *t) if (t->rx_buf) { rx_buf = t->rx_buf; - rx_buf_count = count; + rx_buf_count = davinci_spi->rcount; } else { rx_buf = davinci_spi->rx_tmp_buf; rx_buf_count = sizeof(davinci_spi->rx_tmp_buf); @@ -727,13 +728,14 @@ static int davinci_spi_bufs_dma(struct spi_device *spi, struct spi_transfer *t) dev_dbg(sdev, "Couldn't DMA map a %d bytes RX buffer\n", rx_buf_count); if (t->tx_buf) - dma_unmap_single(NULL, t->tx_dma, count, DMA_TO_DEVICE); + dma_unmap_single(NULL, t->tx_dma, davinci_spi->wcount, + DMA_TO_DEVICE); return -ENOMEM; } param.opt = TCINTEN | EDMA_TCC(davinci_spi_dma->dma_rx_channel); param.src = rx_reg; - param.a_b_cnt = count << 16 | data_type; + param.a_b_cnt = davinci_spi->rcount << 16 | data_type; param.dst = t->rx_dma; param.src_dst_bidx = (t->rx_buf ? data_type : 0) << 16; param.link_bcntrld = 0xffff; @@ -754,7 +756,8 @@ static int davinci_spi_bufs_dma(struct spi_device *spi, struct spi_transfer *t) wait_for_completion_interruptible(&davinci_spi_dma->dma_rx_completion); if (t->tx_buf) - dma_unmap_single(NULL, t->tx_dma, count, DMA_TO_DEVICE); + dma_unmap_single(NULL, t->tx_dma, davinci_spi->wcount, + DMA_TO_DEVICE); dma_unmap_single(NULL, t->rx_dma, rx_buf_count, DMA_FROM_DEVICE); @@ -770,15 +773,21 @@ static int davinci_spi_bufs_dma(struct spi_device *spi, struct spi_transfer *t) if (ret != 0) return ret; + if (davinci_spi->rcount != 0 || davinci_spi->wcount != 0) { + dev_err(sdev, "SPI data transfer error\n"); + return -EIO; + } + return t->len; } -static int davinci_spi_request_dma(struct davinci_spi_dma *davinci_spi_dma) +static int davinci_spi_request_dma(struct davinci_spi *davinci_spi) { int r; + struct davinci_spi_dma *davinci_spi_dma = &davinci_spi->dma_channels; r = edma_alloc_channel(davinci_spi_dma->dma_rx_channel, - davinci_spi_dma_rx_callback, davinci_spi_dma, + davinci_spi_dma_rx_callback, davinci_spi, davinci_spi_dma->eventq); if (r < 0) { pr_err("Unable to request DMA channel for SPI RX\n"); @@ -787,7 +796,7 @@ static int davinci_spi_request_dma(struct davinci_spi_dma *davinci_spi_dma) } r = edma_alloc_channel(davinci_spi_dma->dma_tx_channel, - davinci_spi_dma_tx_callback, davinci_spi_dma, + davinci_spi_dma_tx_callback, davinci_spi, davinci_spi_dma->eventq); if (r < 0) { pr_err("Unable to request DMA channel for SPI TX\n"); @@ -929,7 +938,7 @@ static int davinci_spi_probe(struct platform_device *pdev) davinci_spi->dma_channels.dma_tx_channel = dma_tx_chan; davinci_spi->dma_channels.eventq = dma_eventq; - ret = davinci_spi_request_dma(&davinci_spi->dma_channels); + ret = davinci_spi_request_dma(davinci_spi); if (ret) goto free_clk;