diff options
Diffstat (limited to 'drivers/spi/spi.c')
| -rw-r--r-- | drivers/spi/spi.c | 31 |
1 files changed, 26 insertions, 5 deletions
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index 289feccca376..9bc9fd10d538 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -1220,6 +1220,11 @@ void spi_unmap_buf(struct spi_controller *ctlr, struct device *dev, spi_unmap_buf_attrs(ctlr, dev, sgt, dir, 0); } +/* Dummy SG for unidirect transfers */ +static struct scatterlist dummy_sg = { + .page_link = SG_END, +}; + static int __spi_map_msg(struct spi_controller *ctlr, struct spi_message *msg) { struct device *tx_dev, *rx_dev; @@ -1243,6 +1248,7 @@ static int __spi_map_msg(struct spi_controller *ctlr, struct spi_message *msg) else rx_dev = ctlr->dev.parent; + ret = -ENOMSG; list_for_each_entry(xfer, &msg->transfers, transfer_list) { /* The sync is done before each transfer. */ unsigned long attrs = DMA_ATTR_SKIP_CPU_SYNC; @@ -1257,6 +1263,8 @@ static int __spi_map_msg(struct spi_controller *ctlr, struct spi_message *msg) attrs); if (ret != 0) return ret; + } else { + xfer->tx_sg.sgl = &dummy_sg; } if (xfer->rx_buf != NULL) { @@ -1270,8 +1278,13 @@ static int __spi_map_msg(struct spi_controller *ctlr, struct spi_message *msg) return ret; } + } else { + xfer->rx_sg.sgl = &dummy_sg; } } + /* No transfer has been mapped, bail out with success */ + if (ret) + return 0; ctlr->cur_rx_dma_dev = rx_dev; ctlr->cur_tx_dma_dev = tx_dev; @@ -1307,7 +1320,7 @@ static int __spi_unmap_msg(struct spi_controller *ctlr, struct spi_message *msg) return 0; } -static void spi_dma_sync_for_device(struct spi_controller *ctlr, +static void spi_dma_sync_for_device(struct spi_controller *ctlr, struct spi_message *msg, struct spi_transfer *xfer) { struct device *rx_dev = ctlr->cur_rx_dma_dev; @@ -1316,11 +1329,14 @@ static void spi_dma_sync_for_device(struct spi_controller *ctlr, if (!ctlr->cur_msg_mapped) return; + if (!ctlr->can_dma(ctlr, msg->spi, xfer)) + return; + dma_sync_sgtable_for_device(tx_dev, &xfer->tx_sg, DMA_TO_DEVICE); dma_sync_sgtable_for_device(rx_dev, &xfer->rx_sg, DMA_FROM_DEVICE); } -static void spi_dma_sync_for_cpu(struct spi_controller *ctlr, +static void spi_dma_sync_for_cpu(struct spi_controller *ctlr, struct spi_message *msg, struct spi_transfer *xfer) { struct device *rx_dev = ctlr->cur_rx_dma_dev; @@ -1329,6 +1345,9 @@ static void spi_dma_sync_for_cpu(struct spi_controller *ctlr, if (!ctlr->cur_msg_mapped) return; + if (!ctlr->can_dma(ctlr, msg->spi, xfer)) + return; + dma_sync_sgtable_for_cpu(rx_dev, &xfer->rx_sg, DMA_FROM_DEVICE); dma_sync_sgtable_for_cpu(tx_dev, &xfer->tx_sg, DMA_TO_DEVICE); } @@ -1346,11 +1365,13 @@ static inline int __spi_unmap_msg(struct spi_controller *ctlr, } static void spi_dma_sync_for_device(struct spi_controller *ctrl, + struct spi_message *msg, struct spi_transfer *xfer) { } static void spi_dma_sync_for_cpu(struct spi_controller *ctrl, + struct spi_message *msg, struct spi_transfer *xfer) { } @@ -1622,10 +1643,10 @@ static int spi_transfer_one_message(struct spi_controller *ctlr, reinit_completion(&ctlr->xfer_completion); fallback_pio: - spi_dma_sync_for_device(ctlr, xfer); + spi_dma_sync_for_device(ctlr, msg, xfer); ret = ctlr->transfer_one(ctlr, msg->spi, xfer); if (ret < 0) { - spi_dma_sync_for_cpu(ctlr, xfer); + spi_dma_sync_for_cpu(ctlr, msg, xfer); if (ctlr->cur_msg_mapped && (xfer->error & SPI_TRANS_FAIL_NO_START)) { @@ -1650,7 +1671,7 @@ fallback_pio: msg->status = ret; } - spi_dma_sync_for_cpu(ctlr, xfer); + spi_dma_sync_for_cpu(ctlr, msg, xfer); } else { if (xfer->len) dev_err(&msg->spi->dev, |