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ARM: 6632/3: mmci: stop using the blockend interrupts
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Implement a suggestion from Russell to drop the use of blockend
interrupts altogether and instead rely on the data counter.

Tested with error-free cards on U300, U8500 and RealView PB1176.

Signed-off-by: Ulf Hansson <ulf.hansson@stericsson.com>
Signed-off-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
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Linus Walleij authored and Russell King committed Jan 24, 2011
1 parent 1bae4ce commit 8cb2815
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Showing 2 changed files with 21 additions and 82 deletions.
98 changes: 20 additions & 78 deletions drivers/mmc/host/mmci.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -46,10 +46,6 @@ static unsigned int fmax = 515633;
* is asserted (likewise for RX)
* @fifohalfsize: number of bytes that can be written when MCI_TXFIFOHALFEMPTY
* is asserted (likewise for RX)
* @broken_blockend: the MCI_DATABLOCKEND is broken on the hardware
* and will not work at all.
* @broken_blockend_dma: the MCI_DATABLOCKEND is broken on the hardware when
* using DMA.
* @sdio: variant supports SDIO
* @st_clkdiv: true if using a ST-specific clock divider algorithm
*/
Expand All @@ -59,8 +55,6 @@ struct variant_data {
unsigned int datalength_bits;
unsigned int fifosize;
unsigned int fifohalfsize;
bool broken_blockend;
bool broken_blockend_dma;
bool sdio;
bool st_clkdiv;
};
Expand All @@ -76,7 +70,6 @@ static struct variant_data variant_u300 = {
.fifohalfsize = 8 * 4,
.clkreg_enable = 1 << 13, /* HWFCEN */
.datalength_bits = 16,
.broken_blockend_dma = true,
.sdio = true,
};

Expand All @@ -86,7 +79,6 @@ static struct variant_data variant_ux500 = {
.clkreg = MCI_CLK_ENABLE,
.clkreg_enable = 1 << 14, /* HWFCEN */
.datalength_bits = 24,
.broken_blockend = true,
.sdio = true,
.st_clkdiv = true,
};
Expand Down Expand Up @@ -210,8 +202,6 @@ static void mmci_start_data(struct mmci_host *host, struct mmc_data *data)
host->data = data;
host->size = data->blksz * data->blocks;
host->data_xfered = 0;
host->blockend = false;
host->dataend = false;

mmci_init_sg(host, data);

Expand Down Expand Up @@ -288,21 +278,26 @@ static void
mmci_data_irq(struct mmci_host *host, struct mmc_data *data,
unsigned int status)
{
struct variant_data *variant = host->variant;

/* First check for errors */
if (status & (MCI_DATACRCFAIL|MCI_DATATIMEOUT|MCI_TXUNDERRUN|MCI_RXOVERRUN)) {
u32 remain, success;

/* Calculate how far we are into the transfer */
remain = readl(host->base + MMCIDATACNT) << 2;
success = data->blksz * data->blocks - remain;

dev_dbg(mmc_dev(host->mmc), "MCI ERROR IRQ (status %08x)\n", status);
if (status & MCI_DATACRCFAIL)
if (status & MCI_DATACRCFAIL) {
/* Last block was not successful */
host->data_xfered = ((success / data->blksz) - 1 * data->blksz);
data->error = -EILSEQ;
else if (status & MCI_DATATIMEOUT)
} else if (status & MCI_DATATIMEOUT) {
host->data_xfered = success;
data->error = -ETIMEDOUT;
else if (status & (MCI_TXUNDERRUN|MCI_RXOVERRUN))
} else if (status & (MCI_TXUNDERRUN|MCI_RXOVERRUN)) {
host->data_xfered = success;
data->error = -EIO;

/* Force-complete the transaction */
host->blockend = true;
host->dataend = true;
}

/*
* We hit an error condition. Ensure that any data
Expand All @@ -321,61 +316,14 @@ mmci_data_irq(struct mmci_host *host, struct mmc_data *data,
}
}

/*
* On ARM variants in PIO mode, MCI_DATABLOCKEND
* is always sent first, and we increase the
* transfered number of bytes for that IRQ. Then
* MCI_DATAEND follows and we conclude the transaction.
*
* On the Ux500 single-IRQ variant MCI_DATABLOCKEND
* doesn't seem to immediately clear from the status,
* so we can't use it keep count when only one irq is
* used because the irq will hit for other reasons, and
* then the flag is still up. So we use the MCI_DATAEND
* IRQ at the end of the entire transfer because
* MCI_DATABLOCKEND is broken.
*
* In the U300, the IRQs can arrive out-of-order,
* e.g. MCI_DATABLOCKEND sometimes arrives after MCI_DATAEND,
* so for this case we use the flags "blockend" and
* "dataend" to make sure both IRQs have arrived before
* concluding the transaction. (This does not apply
* to the Ux500 which doesn't fire MCI_DATABLOCKEND
* at all.) In DMA mode it suffers from the same problem
* as the Ux500.
*/
if (status & MCI_DATABLOCKEND) {
/*
* Just being a little over-cautious, we do not
* use this progressive update if the hardware blockend
* flag is unreliable: since it can stay high between
* IRQs it will corrupt the transfer counter.
*/
if (!variant->broken_blockend)
host->data_xfered += data->blksz;
host->blockend = true;
}

if (status & MCI_DATAEND)
host->dataend = true;
if (status & MCI_DATABLOCKEND)
dev_err(mmc_dev(host->mmc), "stray MCI_DATABLOCKEND interrupt\n");

/*
* On variants with broken blockend we shall only wait for dataend,
* on others we must sync with the blockend signal since they can
* appear out-of-order.
*/
if (host->dataend && (host->blockend || variant->broken_blockend)) {
if (status & MCI_DATAEND) {
mmci_stop_data(host);

/* Reset these flags */
host->blockend = false;
host->dataend = false;

/*
* Variants with broken blockend flags need to handle the
* end of the entire transfer here.
*/
if (variant->broken_blockend && !data->error)
if (!data->error)
/* The error clause is handled above, success! */
host->data_xfered += data->blksz * data->blocks;

if (!data->stop) {
Expand Down Expand Up @@ -770,7 +718,6 @@ static int __devinit mmci_probe(struct amba_device *dev, struct amba_id *id)
struct variant_data *variant = id->data;
struct mmci_host *host;
struct mmc_host *mmc;
unsigned int mask;
int ret;

/* must have platform data */
Expand Down Expand Up @@ -951,12 +898,7 @@ static int __devinit mmci_probe(struct amba_device *dev, struct amba_id *id)
goto irq0_free;
}

mask = MCI_IRQENABLE;
/* Don't use the datablockend flag if it's broken */
if (variant->broken_blockend)
mask &= ~MCI_DATABLOCKEND;

writel(mask, host->base + MMCIMASK0);
writel(MCI_IRQENABLE, host->base + MMCIMASK0);

amba_set_drvdata(dev, mmc);

Expand Down
5 changes: 1 addition & 4 deletions drivers/mmc/host/mmci.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -137,7 +137,7 @@
#define MCI_IRQENABLE \
(MCI_CMDCRCFAILMASK|MCI_DATACRCFAILMASK|MCI_CMDTIMEOUTMASK| \
MCI_DATATIMEOUTMASK|MCI_TXUNDERRUNMASK|MCI_RXOVERRUNMASK| \
MCI_CMDRESPENDMASK|MCI_CMDSENTMASK|MCI_DATABLOCKENDMASK)
MCI_CMDRESPENDMASK|MCI_CMDSENTMASK)

/* These interrupts are directed to IRQ1 when two IRQ lines are available */
#define MCI_IRQ1MASK \
Expand Down Expand Up @@ -177,9 +177,6 @@ struct mmci_host {
struct timer_list timer;
unsigned int oldstat;

bool blockend;
bool dataend;

/* pio stuff */
struct sg_mapping_iter sg_miter;
unsigned int size;
Expand Down

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