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Commit ef17fee1 authored by Guennadi Liakhovetski's avatar Guennadi Liakhovetski Committed by Chris Ball
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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: default avatarGuennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: default avatarChris Ball <cjb@laptop.org>
parent 729b0c79

drivers/mmc/host/tmio_mmc.c

+25 −44
Original line number Original line Diff line number Diff line
@@ -427,11 +427,12 @@ static void tmio_dma_complete(void *arg) 
		enable_mmc_irqs(host, TMIO_STAT_DATAEND);

		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 scatterlist *sg = host->sg_ptr;

	struct dma_async_tx_descriptor *desc = NULL;

	struct dma_async_tx_descriptor *desc = NULL;

	struct dma_chan *chan = host->chan_rx;

	struct dma_chan *chan = host->chan_rx;

	dma_cookie_t cookie;

	int ret;

	int ret;





	ret = dma_map_sg(&host->pdev->dev, sg, host->sg_len, DMA_FROM_DEVICE);

	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) {

	if (desc) {

		host->desc = desc;

		desc->callback = tmio_dma_complete;

		desc->callback = tmio_dma_complete;

		desc->callback_param = host;

		desc->callback_param = host;

		host->cookie = desc->tx_submit(desc);

		cookie = desc->tx_submit(desc);

		if (host->cookie < 0) {

		if (cookie < 0) {

			host->desc = NULL;

			desc = NULL;

			ret = host->cookie;

			ret = cookie;

		} else {

		} else {

			chan->device->device_issue_pending(chan);

			chan->device->device_issue_pending(chan);

		}

		}

	}

	}

	dev_dbg(&host->pdev->dev, "%s(): mapped %d -> %d, cookie %d, rq %p\n",

	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 */

		/* DMA failed, fall back to PIO */

		if (ret >= 0)

		if (ret >= 0)

			ret = -EIO;

			ret = -EIO;
@@ -471,23 +471,18 @@ static int tmio_mmc_start_dma_rx(struct tmio_mmc_host *host) 
		dev_warn(&host->pdev->dev,

		dev_warn(&host->pdev->dev,

			 "DMA failed: %d, falling back to PIO\n", ret);

			 "DMA failed: %d, falling back to PIO\n", ret);

		tmio_mmc_enable_dma(host, false);

		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__,

	dev_dbg(&host->pdev->dev, "%s(): desc %p, cookie %d, sg[%d]\n", __func__,

		desc, host->cookie, host->sg_len);

		desc, cookie, host->sg_len);



	return ret > 0 ? 0 : ret;

}

}





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 scatterlist *sg = host->sg_ptr;

	struct dma_async_tx_descriptor *desc = NULL;

	struct dma_async_tx_descriptor *desc = NULL;

	struct dma_chan *chan = host->chan_tx;

	struct dma_chan *chan = host->chan_tx;

	dma_cookie_t cookie;

	int ret;

	int ret;





	ret = dma_map_sg(&host->pdev->dev, sg, host->sg_len, DMA_TO_DEVICE);

	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) {

	if (desc) {

		host->desc = desc;

		desc->callback = tmio_dma_complete;

		desc->callback = tmio_dma_complete;

		desc->callback_param = host;

		desc->callback_param = host;

		host->cookie = desc->tx_submit(desc);

		cookie = desc->tx_submit(desc);

		if (host->cookie < 0) {

		if (cookie < 0) {

			host->desc = NULL;

			desc = NULL;

			ret = host->cookie;

			ret = cookie;

		}

		}

	}

	}

	dev_dbg(&host->pdev->dev, "%s(): mapped %d -> %d, cookie %d, rq %p\n",

	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 */

		/* DMA failed, fall back to PIO */

		if (ret >= 0)

		if (ret >= 0)

			ret = -EIO;

			ret = -EIO;
@@ -525,30 +519,22 @@ static int tmio_mmc_start_dma_tx(struct tmio_mmc_host *host) 
		dev_warn(&host->pdev->dev,

		dev_warn(&host->pdev->dev,

			 "DMA failed: %d, falling back to PIO\n", ret);

			 "DMA failed: %d, falling back to PIO\n", ret);

		tmio_mmc_enable_dma(host, false);

		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__,

	dev_dbg(&host->pdev->dev, "%s(): desc %p, cookie %d\n", __func__,

		desc, host->cookie);

		desc, cookie);



	return ret > 0 ? 0 : ret;

}

}





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)

			       struct mmc_data *data)

{

{

	if (data->flags & MMC_DATA_READ) {

	if (data->flags & MMC_DATA_READ) {

		if (host->chan_rx)

		if (host->chan_rx)

			return tmio_mmc_start_dma_rx(host);

			tmio_mmc_start_dma_rx(host);

	} else {

	} else {

		if (host->chan_tx)

		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)

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,

static void tmio_mmc_request_dma(struct tmio_mmc_host *host,

				 struct tmio_mmc_data *pdata)

				 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 */

	/* We can only either use DMA for both Tx and Rx or not use it at all */

	if (pdata->dma) {

	if (pdata->dma) {

		dma_cap_mask_t mask;

		dma_cap_mask_t mask;
@@ -632,15 +615,11 @@ static void tmio_mmc_release_dma(struct tmio_mmc_host *host) 
		host->chan_rx = NULL;

		host->chan_rx = NULL;

		dma_release_channel(chan);

		dma_release_channel(chan);

	}

	}



	host->cookie = -EINVAL;

	host->desc = NULL;

}

}

#else

#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)

			       struct mmc_data *data)

{

{

	return 0;

}

}





static void tmio_mmc_request_dma(struct tmio_mmc_host *host,

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_SD_XFER_LEN, data->blksz);

	sd_ctrl_write16(host, CTL_XFER_BLK_COUNT, data->blocks);

	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 */

/* Process requests from the MMC layer */

drivers/mmc/host/tmio_mmc.h

+0 −2
Original line number Original line Diff line number Diff line
@@ -112,9 +112,7 @@ struct tmio_mmc_host { 
	struct tasklet_struct	dma_complete;

	struct tasklet_struct	dma_complete;

	struct tasklet_struct	dma_issue;

	struct tasklet_struct	dma_issue;

#ifdef CONFIG_TMIO_MMC_DMA

#ifdef CONFIG_TMIO_MMC_DMA

	struct dma_async_tx_descriptor *desc;

	unsigned int            dma_sglen;

	unsigned int            dma_sglen;

	dma_cookie_t		cookie;

#endif

#endif

};

};