diff options
| author | Pierre Ossman <drzeus@drzeus.cx> | 2007-12-02 19:52:11 +0100 |
|---|---|---|
| committer | Pierre Ossman <drzeus@drzeus.cx> | 2007-12-12 20:01:00 +0100 |
| commit | c9fddbc4f844f5a16b5957c61fe2cfcb5c12f990 (patch) | |
| tree | 0bc8f857acfb7c47ab4c7231ffab5c8628b714c3 | |
| parent | c6573c94670882079174e2ea0da4abf1a0da51fe (diff) | |
| download | linux-c9fddbc4f844f5a16b5957c61fe2cfcb5c12f990.tar.bz2 | |
sdhci: use PIO when DMA can't satisfy the request
Some controllers have been designed on the assumption that all transfers
will be 32-bit aligned, both in start address and in size. This is not a
guarantee the SDHCI specification provides and not one we can provide.
Revert back to PIO for individual requests in order to work around the
hardware bug.
Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>
| -rw-r--r-- | drivers/mmc/host/sdhci.c | 32 | ||||
| -rw-r--r-- | drivers/mmc/host/sdhci.h | 3 |
2 files changed, 31 insertions, 4 deletions
diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c index 758a7417eb50..a5300f238d98 100644 --- a/drivers/mmc/host/sdhci.c +++ b/drivers/mmc/host/sdhci.c @@ -43,6 +43,10 @@ static unsigned int debug_quirks = 0; #define SDHCI_QUIRK_RESET_CMD_DATA_ON_IOS (1<<4) /* Controller has an unusable DMA engine */ #define SDHCI_QUIRK_BROKEN_DMA (1<<5) +/* Controller can only DMA from 32-bit aligned addresses */ +#define SDHCI_QUIRK_32BIT_DMA_ADDR (1<<6) +/* Controller can only DMA chunk sizes that are a multiple of 32 bits */ +#define SDHCI_QUIRK_32BIT_DMA_SIZE (1<<7) static const struct pci_device_id pci_ids[] __devinitdata = { { @@ -429,7 +433,29 @@ static void sdhci_prepare_data(struct sdhci_host *host, struct mmc_data *data) writeb(count, host->ioaddr + SDHCI_TIMEOUT_CONTROL); - if (host->flags & SDHCI_USE_DMA) { + if (host->flags & SDHCI_USE_DMA) + host->flags |= SDHCI_REQ_USE_DMA; + + if (unlikely((host->flags & SDHCI_REQ_USE_DMA) && + (host->chip->quirks & SDHCI_QUIRK_32BIT_DMA_SIZE) && + ((data->blksz * data->blocks) & 0x3))) { + DBG("Reverting to PIO because of transfer size (%d)\n", + data->blksz * data->blocks); + host->flags &= ~SDHCI_REQ_USE_DMA; + } + + /* + * The assumption here being that alignment is the same after + * translation to device address space. + */ + if (unlikely((host->flags & SDHCI_REQ_USE_DMA) && + (host->chip->quirks & SDHCI_QUIRK_32BIT_DMA_ADDR) && + (data->sg->offset & 0x3))) { + DBG("Reverting to PIO because of bad alignment\n"); + host->flags &= ~SDHCI_REQ_USE_DMA; + } + + if (host->flags & SDHCI_REQ_USE_DMA) { int count; count = pci_map_sg(host->chip->pdev, data->sg, data->sg_len, @@ -466,7 +492,7 @@ static void sdhci_set_transfer_mode(struct sdhci_host *host, mode |= SDHCI_TRNS_MULTI; if (data->flags & MMC_DATA_READ) mode |= SDHCI_TRNS_READ; - if (host->flags & SDHCI_USE_DMA) + if (host->flags & SDHCI_REQ_USE_DMA) mode |= SDHCI_TRNS_DMA; writew(mode, host->ioaddr + SDHCI_TRANSFER_MODE); @@ -482,7 +508,7 @@ static void sdhci_finish_data(struct sdhci_host *host) data = host->data; host->data = NULL; - if (host->flags & SDHCI_USE_DMA) { + if (host->flags & SDHCI_REQ_USE_DMA) { pci_unmap_sg(host->chip->pdev, data->sg, data->sg_len, (data->flags & MMC_DATA_READ)?PCI_DMA_FROMDEVICE:PCI_DMA_TODEVICE); } diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h index 05195ea900f4..e4d77b038bfa 100644 --- a/drivers/mmc/host/sdhci.h +++ b/drivers/mmc/host/sdhci.h @@ -171,7 +171,8 @@ struct sdhci_host { spinlock_t lock; /* Mutex */ int flags; /* Host attributes */ -#define SDHCI_USE_DMA (1<<0) +#define SDHCI_USE_DMA (1<<0) /* Host is DMA capable */ +#define SDHCI_REQ_USE_DMA (1<<1) /* Use DMA for this req. */ unsigned int max_clk; /* Max possible freq (MHz) */ unsigned int timeout_clk; /* Timeout freq (KHz) */ |