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 <g.liakhovetski@xxxxxx>
---
Since this is a bug-fix and it only touches the DMA case, only present on
sh-mobile platforms, this should be good for 2.6.37, Ian?
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 9034414..10416c3 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 0fedc78..0b7d916 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
};
--
1.7.2.3
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