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sdhci: don't check block count for progress
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The specification is insufficiently strict when it comes to how the
hardware should update the block count register, making it useless
for checking transfer progress.

Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>
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Pierre Ossman committed Jul 15, 2008
1 parent 50515af commit c9b74c5
Showing 1 changed file with 9 additions and 14 deletions.
23 changes: 9 additions & 14 deletions drivers/mmc/host/sdhci.c
Original file line number Diff line number Diff line change
Expand Up @@ -567,7 +567,6 @@ static void sdhci_set_transfer_mode(struct sdhci_host *host,
static void sdhci_finish_data(struct sdhci_host *host)
{
struct mmc_data *data;
u16 blocks;

BUG_ON(!host->data);

Expand All @@ -580,20 +579,16 @@ static void sdhci_finish_data(struct sdhci_host *host)
}

/*
* Controller doesn't count down when in single block mode.
* The specification states that the block count register must
* be updated, but it does not specify at what point in the
* data flow. That makes the register entirely useless to read
* back so we have to assume that nothing made it to the card
* in the event of an error.
*/
if (data->blocks == 1)
blocks = (data->error == 0) ? 0 : 1;
if (data->error)
data->bytes_xfered = 0;
else
blocks = readw(host->ioaddr + SDHCI_BLOCK_COUNT);
data->bytes_xfered = data->blksz * (data->blocks - blocks);

if (!data->error && blocks) {
printk(KERN_ERR "%s: Controller signalled completion even "
"though there were blocks left.\n",
mmc_hostname(host->mmc));
data->error = -EIO;
}
data->bytes_xfered = data->blksz * data->blocks;

if (data->stop) {
/*
Expand Down Expand Up @@ -1466,7 +1461,7 @@ static int __devinit sdhci_probe_slot(struct pci_dev *pdev, int slot)
mmc->ops = &sdhci_ops;
mmc->f_min = host->max_clk / 256;
mmc->f_max = host->max_clk;
mmc->caps = MMC_CAP_4_BIT_DATA | MMC_CAP_MULTIWRITE | MMC_CAP_SDIO_IRQ;
mmc->caps = MMC_CAP_4_BIT_DATA | MMC_CAP_SDIO_IRQ;

if (caps & SDHCI_CAN_DO_HISPD)
mmc->caps |= MMC_CAP_SD_HIGHSPEED;
Expand Down

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