From ef17fee1e559b3faeb6f89963e78ad47731d18a1 Mon Sep 17 00:00:00 2001 From: Guennadi Liakhovetski Date: Thu, 11 Nov 2010 12:19:47 +0100 Subject: [PATCH] mmc: tmio_mmc: fix PIO fallback on DMA descriptor allocation failure The easiest way to fall back to PIO, when a DMA descriptor allocation fails is to disable DMA on the controller but continue with the current request in PIO mode. This way tmio_mmc_start_dma() can become void, since it cannot be failing any more. The current version is also broken: it is testing a wrong pointer and thus failing to recognise, that a descriptor allocation wasn't successful. Signed-off-by: Guennadi Liakhovetski Signed-off-by: Chris Ball --- drivers/mmc/host/tmio_mmc.c | 69 ++++++++++++++----------------------- drivers/mmc/host/tmio_mmc.h | 2 -- 2 files changed, 25 insertions(+), 46 deletions(-) diff --git a/drivers/mmc/host/tmio_mmc.c b/drivers/mmc/host/tmio_mmc.c index 4e75799291ca..63115a6de935 100644 --- a/drivers/mmc/host/tmio_mmc.c +++ b/drivers/mmc/host/tmio_mmc.c @@ -427,11 +427,12 @@ static void tmio_dma_complete(void *arg) enable_mmc_irqs(host, TMIO_STAT_DATAEND); } -static int tmio_mmc_start_dma_rx(struct tmio_mmc_host *host) +static void tmio_mmc_start_dma_rx(struct tmio_mmc_host *host) { struct scatterlist *sg = host->sg_ptr; struct dma_async_tx_descriptor *desc = NULL; struct dma_chan *chan = host->chan_rx; + dma_cookie_t cookie; int ret; ret = dma_map_sg(&host->pdev->dev, sg, host->sg_len, DMA_FROM_DEVICE); @@ -442,21 +443,20 @@ static int tmio_mmc_start_dma_rx(struct tmio_mmc_host *host) } if (desc) { - host->desc = desc; desc->callback = tmio_dma_complete; desc->callback_param = host; - host->cookie = desc->tx_submit(desc); - if (host->cookie < 0) { - host->desc = NULL; - ret = host->cookie; + cookie = desc->tx_submit(desc); + if (cookie < 0) { + desc = NULL; + ret = cookie; } else { chan->device->device_issue_pending(chan); } } dev_dbg(&host->pdev->dev, "%s(): mapped %d -> %d, cookie %d, rq %p\n", - __func__, host->sg_len, ret, host->cookie, host->mrq); + __func__, host->sg_len, ret, cookie, host->mrq); - if (!host->desc) { + if (!desc) { /* DMA failed, fall back to PIO */ if (ret >= 0) ret = -EIO; @@ -471,23 +471,18 @@ static int tmio_mmc_start_dma_rx(struct tmio_mmc_host *host) dev_warn(&host->pdev->dev, "DMA failed: %d, falling back to PIO\n", ret); tmio_mmc_enable_dma(host, false); - reset(host); - /* Fail this request, let above layers recover */ - host->mrq->cmd->error = ret; - tmio_mmc_finish_request(host); } dev_dbg(&host->pdev->dev, "%s(): desc %p, cookie %d, sg[%d]\n", __func__, - desc, host->cookie, host->sg_len); - - return ret > 0 ? 0 : ret; + desc, cookie, host->sg_len); } -static int tmio_mmc_start_dma_tx(struct tmio_mmc_host *host) +static void tmio_mmc_start_dma_tx(struct tmio_mmc_host *host) { struct scatterlist *sg = host->sg_ptr; struct dma_async_tx_descriptor *desc = NULL; struct dma_chan *chan = host->chan_tx; + dma_cookie_t cookie; int ret; ret = dma_map_sg(&host->pdev->dev, sg, host->sg_len, DMA_TO_DEVICE); @@ -498,19 +493,18 @@ static int tmio_mmc_start_dma_tx(struct tmio_mmc_host *host) } if (desc) { - host->desc = desc; desc->callback = tmio_dma_complete; desc->callback_param = host; - host->cookie = desc->tx_submit(desc); - if (host->cookie < 0) { - host->desc = NULL; - ret = host->cookie; + cookie = desc->tx_submit(desc); + if (cookie < 0) { + desc = NULL; + ret = cookie; } } dev_dbg(&host->pdev->dev, "%s(): mapped %d -> %d, cookie %d, rq %p\n", - __func__, host->sg_len, ret, host->cookie, host->mrq); + __func__, host->sg_len, ret, cookie, host->mrq); - if (!host->desc) { + if (!desc) { /* DMA failed, fall back to PIO */ if (ret >= 0) ret = -EIO; @@ -525,30 +519,22 @@ static int tmio_mmc_start_dma_tx(struct tmio_mmc_host *host) dev_warn(&host->pdev->dev, "DMA failed: %d, falling back to PIO\n", ret); tmio_mmc_enable_dma(host, false); - reset(host); - /* Fail this request, let above layers recover */ - host->mrq->cmd->error = ret; - tmio_mmc_finish_request(host); } dev_dbg(&host->pdev->dev, "%s(): desc %p, cookie %d\n", __func__, - desc, host->cookie); - - return ret > 0 ? 0 : ret; + desc, cookie); } -static int tmio_mmc_start_dma(struct tmio_mmc_host *host, +static void tmio_mmc_start_dma(struct tmio_mmc_host *host, struct mmc_data *data) { if (data->flags & MMC_DATA_READ) { if (host->chan_rx) - return tmio_mmc_start_dma_rx(host); + tmio_mmc_start_dma_rx(host); } else { if (host->chan_tx) - return tmio_mmc_start_dma_tx(host); + tmio_mmc_start_dma_tx(host); } - - return 0; } static void tmio_issue_tasklet_fn(unsigned long priv) @@ -584,9 +570,6 @@ static bool tmio_mmc_filter(struct dma_chan *chan, void *arg) static void tmio_mmc_request_dma(struct tmio_mmc_host *host, struct tmio_mmc_data *pdata) { - host->cookie = -EINVAL; - host->desc = NULL; - /* We can only either use DMA for both Tx and Rx or not use it at all */ if (pdata->dma) { dma_cap_mask_t mask; @@ -632,15 +615,11 @@ static void tmio_mmc_release_dma(struct tmio_mmc_host *host) host->chan_rx = NULL; dma_release_channel(chan); } - - host->cookie = -EINVAL; - host->desc = NULL; } #else -static int tmio_mmc_start_dma(struct tmio_mmc_host *host, +static void tmio_mmc_start_dma(struct tmio_mmc_host *host, struct mmc_data *data) { - return 0; } static void tmio_mmc_request_dma(struct tmio_mmc_host *host, @@ -682,7 +661,9 @@ static int tmio_mmc_start_data(struct tmio_mmc_host *host, sd_ctrl_write16(host, CTL_SD_XFER_LEN, data->blksz); sd_ctrl_write16(host, CTL_XFER_BLK_COUNT, data->blocks); - return tmio_mmc_start_dma(host, data); + tmio_mmc_start_dma(host, data); + + return 0; } /* Process requests from the MMC layer */ diff --git a/drivers/mmc/host/tmio_mmc.h b/drivers/mmc/host/tmio_mmc.h index 0fedc78e3ea5..0b7d9162c1b5 100644 --- a/drivers/mmc/host/tmio_mmc.h +++ b/drivers/mmc/host/tmio_mmc.h @@ -112,9 +112,7 @@ struct tmio_mmc_host { struct tasklet_struct dma_complete; struct tasklet_struct dma_issue; #ifdef CONFIG_TMIO_MMC_DMA - struct dma_async_tx_descriptor *desc; unsigned int dma_sglen; - dma_cookie_t cookie; #endif }; -- 2.30.2