atmel_spi: fix hang due to missed interrupt

[pandora-kernel.git] / drivers / spi / atmel_spi.c

diff --git a/drivers/spi/atmel_spi.c b/drivers/spi/atmel_spi.c
index 1749a27..95190c6 100644 (file)
--- a/drivers/spi/atmel_spi.c
+++ b/drivers/spi/atmel_spi.c
@@ -184,7 +184,8 @@ static void atmel_spi_next_xfer(struct spi_master *master,
 {
        struct atmel_spi        *as = spi_master_get_devdata(master);
        struct spi_transfer     *xfer;
-       u32                     len, remaining, total;
+       u32                     len, remaining;
+       u32                     ieval;
        dma_addr_t              tx_dma, rx_dma;
 
        if (!as->current_transfer)
@@ -197,6 +198,8 @@ static void atmel_spi_next_xfer(struct spi_master *master,
                xfer = NULL;
 
        if (xfer) {
+               spi_writel(as, PTCR, SPI_BIT(RXTDIS) | SPI_BIT(TXTDIS));
+
                len = xfer->len;
                atmel_spi_next_xfer_data(master, xfer, &tx_dma, &rx_dma, &len);
                remaining = xfer->len - len;
@@ -234,6 +237,8 @@ static void atmel_spi_next_xfer(struct spi_master *master,
        as->next_transfer = xfer;
 
        if (xfer) {
+               u32     total;
+
                total = len;
                atmel_spi_next_xfer_data(master, xfer, &tx_dma, &rx_dma, &len);
                as->next_remaining_bytes = total - len;
@@ -250,9 +255,11 @@ static void atmel_spi_next_xfer(struct spi_master *master,
                        "  next xfer %p: len %u tx %p/%08x rx %p/%08x\n",
                        xfer, xfer->len, xfer->tx_buf, xfer->tx_dma,
                        xfer->rx_buf, xfer->rx_dma);
+               ieval = SPI_BIT(ENDRX) | SPI_BIT(OVRES);
        } else {
                spi_writel(as, RNCR, 0);
                spi_writel(as, TNCR, 0);
+               ieval = SPI_BIT(RXBUFF) | SPI_BIT(ENDRX) | SPI_BIT(OVRES);
        }
 
        /* REVISIT: We're waiting for ENDRX before we start the next
@@ -265,7 +272,7 @@ static void atmel_spi_next_xfer(struct spi_master *master,
         *
         * It should be doable, though. Just not now...
         */
-       spi_writel(as, IER, SPI_BIT(ENDRX) | SPI_BIT(OVRES));
+       spi_writel(as, IER, ieval);
        spi_writel(as, PTCR, SPI_BIT(TXTEN) | SPI_BIT(RXTEN));
 }
 
@@ -313,14 +320,14 @@ atmel_spi_dma_map_xfer(struct atmel_spi *as, struct spi_transfer *xfer)
                xfer->tx_dma = dma_map_single(dev,
                                (void *) xfer->tx_buf, xfer->len,
                                DMA_TO_DEVICE);
-               if (dma_mapping_error(xfer->tx_dma))
+               if (dma_mapping_error(dev, xfer->tx_dma))
                        return -ENOMEM;
        }
        if (xfer->rx_buf) {
                xfer->rx_dma = dma_map_single(dev,
                                xfer->rx_buf, xfer->len,
                                DMA_FROM_DEVICE);
-               if (dma_mapping_error(xfer->rx_dma)) {
+               if (dma_mapping_error(dev, xfer->rx_dma)) {
                        if (xfer->tx_buf)
                                dma_unmap_single(dev,
                                                xfer->tx_dma, xfer->len,
@@ -396,7 +403,7 @@ atmel_spi_interrupt(int irq, void *dev_id)
 
                ret = IRQ_HANDLED;
 
-               spi_writel(as, IDR, (SPI_BIT(ENDTX) | SPI_BIT(ENDRX)
+               spi_writel(as, IDR, (SPI_BIT(RXBUFF) | SPI_BIT(ENDRX)
                                     | SPI_BIT(OVRES)));
 
                /*
@@ -418,7 +425,7 @@ atmel_spi_interrupt(int irq, void *dev_id)
                if (xfer->delay_usecs)
                        udelay(xfer->delay_usecs);
 
-               dev_warn(master->dev.parent, "fifo overrun (%u/%u remaining)\n",
+               dev_warn(master->dev.parent, "overrun (%u/%u remaining)\n",
                         spi_readl(as, TCR), spi_readl(as, RCR));
 
                /*
@@ -442,7 +449,7 @@ atmel_spi_interrupt(int irq, void *dev_id)
                spi_readl(as, SR);
 
                atmel_spi_msg_done(master, as, msg, -EIO, 0);
-       } else if (pending & SPI_BIT(ENDRX)) {
+       } else if (pending & (SPI_BIT(RXBUFF) | SPI_BIT(ENDRX))) {
                ret = IRQ_HANDLED;
 
                spi_writel(as, IDR, pending);
@@ -497,7 +504,7 @@ static int atmel_spi_setup(struct spi_device *spi)
        struct atmel_spi        *as;
        u32                     scbr, csr;
        unsigned int            bits = spi->bits_per_word;
-       unsigned long           bus_hz, sck_hz;
+       unsigned long           bus_hz;
        unsigned int            npcs_pin;
        int                     ret;
 
@@ -536,14 +543,25 @@ static int atmel_spi_setup(struct spi_device *spi)
                return -EINVAL;
        }
 
-       /* speed zero convention is used by some upper layers */
+       /*
+        * Pre-new_1 chips start out at half the peripheral
+        * bus speed.
+        */
        bus_hz = clk_get_rate(as->clk);
+       if (!as->new_1)
+               bus_hz /= 2;
+
        if (spi->max_speed_hz) {
-               /* assume div32/fdiv/mbz == 0 */
-               if (!as->new_1)
-                       bus_hz /= 2;
-               scbr = ((bus_hz + spi->max_speed_hz - 1)
-                       / spi->max_speed_hz);
+               /*
+                * Calculate the lowest divider that satisfies the
+                * constraint, assuming div32/fdiv/mbz == 0.
+                */
+               scbr = DIV_ROUND_UP(bus_hz, spi->max_speed_hz);
+
+               /*
+                * If the resulting divider doesn't fit into the
+                * register bitfield, we can't satisfy the constraint.
+                */
                if (scbr >= (1 << SPI_SCBR_SIZE)) {
                        dev_dbg(&spi->dev,
                                "setup: %d Hz too slow, scbr %u; min %ld Hz\n",
@@ -551,8 +569,8 @@ static int atmel_spi_setup(struct spi_device *spi)
                        return -EINVAL;
                }
        } else
+               /* speed zero means "as slow as possible" */
                scbr = 0xff;
-       sck_hz = bus_hz / scbr;
 
        csr = SPI_BF(SCBR, scbr) | SPI_BF(BITS, bits - 8);
        if (spi->mode & SPI_CPOL)
@@ -589,7 +607,7 @@ static int atmel_spi_setup(struct spi_device *spi)
 
        dev_dbg(&spi->dev,
                "setup: %lu Hz bpw %u mode 0x%x -> csr%d %08x\n",
-               sck_hz, bits, spi->mode, spi->chip_select, csr);
+               bus_hz / scbr, bits, spi->mode, spi->chip_select, csr);
 
        spi_writel(as, CSR0 + 4 * spi->chip_select, csr);
 
@@ -616,7 +634,7 @@ static int atmel_spi_transfer(struct spi_device *spi, struct spi_message *msg)
                return -ESHUTDOWN;
 
        list_for_each_entry(xfer, &msg->transfers, transfer_list) {
-               if (!(xfer->tx_buf || xfer->rx_buf)) {
+               if (!(xfer->tx_buf || xfer->rx_buf) && xfer->len) {
                        dev_dbg(&spi->dev, "missing rx or tx buf\n");
                        return -EINVAL;
                }