spi: omap2-mcspi: Undo broken fix for dma transfer of vmalloced buffer
authorAkinobu Mita <akinobu.mita@gmail.com>
Fri, 8 Apr 2016 18:43:15 +0000 (03:43 +0900)
committerMark Brown <broonie@kernel.org>
Tue, 12 Apr 2016 01:21:14 +0000 (02:21 +0100)
This reverts commit 3525e0aac91c4de5d20b1f22a6c6e2b39db3cc96.

The DMA transfer for RX buffer was not handled correctly in this change.

The actual transfer length for DMA RX can be less than xfer->len in the
specific condition and the last words will be filled after the DMA
completion, but the commit doesn't consider it and the dmaengine is
started with rx_sg mapped by spi core.

The solution for this at least requires more lines than this commit
has inserted.  So revert it for now.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
drivers/spi/spi-omap2-mcspi.c

index 43a02e3..0caa3c8 100644 (file)
@@ -423,12 +423,16 @@ static void omap2_mcspi_tx_dma(struct spi_device *spi,
 
        if (mcspi_dma->dma_tx) {
                struct dma_async_tx_descriptor *tx;
+               struct scatterlist sg;
 
                dmaengine_slave_config(mcspi_dma->dma_tx, &cfg);
 
-               tx = dmaengine_prep_slave_sg(mcspi_dma->dma_tx, xfer->tx_sg.sgl,
-                                            xfer->tx_sg.nents, DMA_MEM_TO_DEV,
-                                            DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
+               sg_init_table(&sg, 1);
+               sg_dma_address(&sg) = xfer->tx_dma;
+               sg_dma_len(&sg) = xfer->len;
+
+               tx = dmaengine_prep_slave_sg(mcspi_dma->dma_tx, &sg, 1,
+               DMA_MEM_TO_DEV, DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
                if (tx) {
                        tx->callback = omap2_mcspi_tx_callback;
                        tx->callback_param = spi;
@@ -474,15 +478,20 @@ omap2_mcspi_rx_dma(struct spi_device *spi, struct spi_transfer *xfer,
 
        if (mcspi_dma->dma_rx) {
                struct dma_async_tx_descriptor *tx;
+               struct scatterlist sg;
 
                dmaengine_slave_config(mcspi_dma->dma_rx, &cfg);
 
                if ((l & OMAP2_MCSPI_CHCONF_TURBO) && mcspi->fifo_depth == 0)
                        dma_count -= es;
 
-               tx = dmaengine_prep_slave_sg(mcspi_dma->dma_rx, xfer->rx_sg.sgl,
-                                            xfer->rx_sg.nents, DMA_DEV_TO_MEM,
-                                            DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
+               sg_init_table(&sg, 1);
+               sg_dma_address(&sg) = xfer->rx_dma;
+               sg_dma_len(&sg) = dma_count;
+
+               tx = dmaengine_prep_slave_sg(mcspi_dma->dma_rx, &sg, 1,
+                               DMA_DEV_TO_MEM, DMA_PREP_INTERRUPT |
+                               DMA_CTRL_ACK);
                if (tx) {
                        tx->callback = omap2_mcspi_rx_callback;
                        tx->callback_param = spi;
@@ -496,6 +505,8 @@ omap2_mcspi_rx_dma(struct spi_device *spi, struct spi_transfer *xfer,
        omap2_mcspi_set_dma_req(spi, 1, 1);
 
        wait_for_completion(&mcspi_dma->dma_rx_completion);
+       dma_unmap_single(mcspi->dev, xfer->rx_dma, count,
+                        DMA_FROM_DEVICE);
 
        if (mcspi->fifo_depth > 0)
                return count;
@@ -608,6 +619,8 @@ omap2_mcspi_txrx_dma(struct spi_device *spi, struct spi_transfer *xfer)
 
        if (tx != NULL) {
                wait_for_completion(&mcspi_dma->dma_tx_completion);
+               dma_unmap_single(mcspi->dev, xfer->tx_dma, xfer->len,
+                                DMA_TO_DEVICE);
 
                if (mcspi->fifo_depth > 0) {
                        irqstat_reg = mcspi->base + OMAP2_MCSPI_IRQSTATUS;
@@ -1074,16 +1087,6 @@ static void omap2_mcspi_cleanup(struct spi_device *spi)
                gpio_free(spi->cs_gpio);
 }
 
-static bool omap2_mcspi_can_dma(struct spi_master *master,
-                               struct spi_device *spi,
-                               struct spi_transfer *xfer)
-{
-       if (xfer->len < DMA_MIN_BYTES)
-               return false;
-
-       return true;
-}
-
 static int omap2_mcspi_work_one(struct omap2_mcspi *mcspi,
                struct spi_device *spi, struct spi_transfer *t)
 {
@@ -1265,6 +1268,32 @@ static int omap2_mcspi_transfer_one(struct spi_master *master,
                return -EINVAL;
        }
 
+       if (len < DMA_MIN_BYTES)
+               goto skip_dma_map;
+
+       if (mcspi_dma->dma_tx && tx_buf != NULL) {
+               t->tx_dma = dma_map_single(mcspi->dev, (void *) tx_buf,
+                               len, DMA_TO_DEVICE);
+               if (dma_mapping_error(mcspi->dev, t->tx_dma)) {
+                       dev_dbg(mcspi->dev, "dma %cX %d bytes error\n",
+                                       'T', len);
+                       return -EINVAL;
+               }
+       }
+       if (mcspi_dma->dma_rx && rx_buf != NULL) {
+               t->rx_dma = dma_map_single(mcspi->dev, rx_buf, t->len,
+                               DMA_FROM_DEVICE);
+               if (dma_mapping_error(mcspi->dev, t->rx_dma)) {
+                       dev_dbg(mcspi->dev, "dma %cX %d bytes error\n",
+                                       'R', len);
+                       if (tx_buf != NULL)
+                               dma_unmap_single(mcspi->dev, t->tx_dma,
+                                               len, DMA_TO_DEVICE);
+                       return -EINVAL;
+               }
+       }
+
+skip_dma_map:
        return omap2_mcspi_work_one(mcspi, spi, t);
 }
 
@@ -1348,7 +1377,6 @@ static int omap2_mcspi_probe(struct platform_device *pdev)
        master->transfer_one = omap2_mcspi_transfer_one;
        master->set_cs = omap2_mcspi_set_cs;
        master->cleanup = omap2_mcspi_cleanup;
-       master->can_dma = omap2_mcspi_can_dma;
        master->dev.of_node = node;
        master->max_speed_hz = OMAP2_MCSPI_MAX_FREQ;
        master->min_speed_hz = OMAP2_MCSPI_MAX_FREQ >> 15;