ARM: 6632/3: mmci: stop using the blockend interrupts

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>

2 files changed, 21 insertions, 82 deletions

diff --git a/drivers/mmc/host/mmci.c b/drivers/mmc/host/mmci.c
index 563022825667..2de12fe155da 100644
--- a/drivers/mmc/host/mmci.c
+++ b/drivers/mmc/host/mmci.c
@@ -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
  */
@@ -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;
 };
@@ -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,
 };
 
@@ -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,
 };
@@ -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);
 
@@ -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
@@ -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) {
@@ -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 */
@@ -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);
 
diff --git a/drivers/mmc/host/mmci.h b/drivers/mmc/host/mmci.h
index df06f01aac89..c1df7b82d36c 100644
--- a/drivers/mmc/host/mmci.h
+++ b/drivers/mmc/host/mmci.h
@@ -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 \
@@ -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;