sdhci: graceful handling of bad addresses

Be a bit more robust and fall back to PIO if someone is feeding us
bogus addresses.

Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>

1 files changed, 57 insertions, 20 deletions

diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index b802044ea940..d3e4a391e351 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -327,7 +327,7 @@ static void sdhci_kunmap_atomic(void *buffer, unsigned long *flags)
         local_irq_restore(*flags);
 }
 
-static void sdhci_adma_table_pre(struct sdhci_host *host,
+static int sdhci_adma_table_pre(struct sdhci_host *host,
         struct mmc_data *data)
 {
         int direction;
@@ -360,10 +360,14 @@ static void sdhci_adma_table_pre(struct sdhci_host *host,
 
         host->align_addr = dma_map_single(mmc_dev(host->mmc),
                 host->align_buffer, 128 * 4, direction);
+        if (dma_mapping_error(host->align_addr))
+                goto fail;
         BUG_ON(host->align_addr & 0x3);
 
         host->sg_count = dma_map_sg(mmc_dev(host->mmc),
                 data->sg, data->sg_len, direction);
+        if (host->sg_count == 0)
+                goto unmap_align;
 
         desc = host->adma_desc;
         align = host->align_buffer;
@@ -457,7 +461,20 @@ static void sdhci_adma_table_pre(struct sdhci_host *host,
 
         host->adma_addr = dma_map_single(mmc_dev(host->mmc),
                 host->adma_desc, (128 * 2 + 1) * 4, DMA_TO_DEVICE);
+        if (dma_mapping_error(host->align_addr))
+                goto unmap_entries;
         BUG_ON(host->adma_addr & 0x3);
+
+        return 0;
+
+unmap_entries:
+        dma_unmap_sg(mmc_dev(host->mmc), data->sg,
+                data->sg_len, direction);
+unmap_align:
+        dma_unmap_single(mmc_dev(host->mmc), host->align_addr,
+                128 * 4, direction);
+fail:
+        return -EINVAL;
 }
 
 static void sdhci_adma_table_post(struct sdhci_host *host,
@@ -555,6 +572,7 @@ static void sdhci_prepare_data(struct sdhci_host *host, struct mmc_data *data)
 {
         u8 count;
         u8 ctrl;
+        int ret;
 
         WARN_ON(host->data);
 
@@ -639,6 +657,43 @@ static void sdhci_prepare_data(struct sdhci_host *host, struct mmc_data *data)
                 }
         }
 
+        if (host->flags & SDHCI_REQ_USE_DMA) {
+                if (host->flags & SDHCI_USE_ADMA) {
+                        ret = sdhci_adma_table_pre(host, data);
+                        if (ret) {
+                                /*
+                                 * This only happens when someone fed
+                                 * us an invalid request.
+                                 */
+                                WARN_ON(1);
+                                host->flags &= ~SDHCI_USE_DMA;
+                        } else {
+                                writel(host->adma_addr,
+                                        host->ioaddr + SDHCI_ADMA_ADDRESS);
+                        }
+                } else {
+                        int count;
+
+                        count = dma_map_sg(mmc_dev(host->mmc),
+                                        data->sg, data->sg_len,
+                                        (data->flags & MMC_DATA_READ) ?
+                                                DMA_FROM_DEVICE :
+                                                DMA_TO_DEVICE);
+                        if (count == 0) {
+                                /*
+                                 * This only happens when someone fed
+                                 * us an invalid request.
+                                 */
+                                WARN_ON(1);
+                                host->flags &= ~SDHCI_USE_DMA;
+                        } else {
+                                WARN_ON(count != 1);
+                                writel(sg_dma_address(data->sg),
+                                        host->ioaddr + SDHCI_DMA_ADDRESS);
+                        }
+                }
+        }
+
         /*
          * Always adjust the DMA selection as some controllers
          * (e.g. JMicron) can't do PIO properly when the selection
@@ -655,25 +710,7 @@ static void sdhci_prepare_data(struct sdhci_host *host, struct mmc_data *data)
                 writeb(ctrl, host->ioaddr + SDHCI_HOST_CONTROL);
         }
 
-        if (host->flags & SDHCI_REQ_USE_DMA) {
-                if (host->flags & SDHCI_USE_ADMA) {
-                        sdhci_adma_table_pre(host, data);
-                        writel(host->adma_addr,
-                                host->ioaddr + SDHCI_ADMA_ADDRESS);
-                } else {
-                        int count;
-
-                        count = dma_map_sg(mmc_dev(host->mmc),
-                                        data->sg, data->sg_len,
-                                        (data->flags & MMC_DATA_READ) ?
-                                                DMA_FROM_DEVICE :
-                                                DMA_TO_DEVICE);
-                        WARN_ON(count != 1);
-
-                        writel(sg_dma_address(data->sg),
-                                host->ioaddr + SDHCI_DMA_ADDRESS);
-                }
-        } else {
+        if (!(host->flags & SDHCI_REQ_USE_DMA)) {
                 host->cur_sg = data->sg;
                 host->num_sg = data->sg_len;