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Diffstat (limited to 'drivers/spi/spi-qcom-qspi.c')
| -rw-r--r-- | drivers/spi/spi-qcom-qspi.c | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/drivers/spi/spi-qcom-qspi.c b/drivers/spi/spi-qcom-qspi.c index 9b3092e22942..db1dd133762e 100644 --- a/drivers/spi/spi-qcom-qspi.c +++ b/drivers/spi/spi-qcom-qspi.c @@ -357,10 +357,22 @@ static int qcom_qspi_setup_dma_desc(struct qcom_qspi *ctrl, for (i = 0; i < sgt->nents; i++) { dma_ptr_sg = sg_dma_address(sgt->sgl + i); + dma_len_sg = sg_dma_len(sgt->sgl + i); if (!IS_ALIGNED(dma_ptr_sg, QSPI_ALIGN_REQ)) { dev_warn_once(ctrl->dev, "dma_address not aligned to %d\n", QSPI_ALIGN_REQ); return -EAGAIN; } + /* + * When reading with DMA the controller writes to memory 1 word + * at a time. If the length isn't a multiple of 4 bytes then + * the controller can clobber the things later in memory. + * Fallback to PIO to be safe. + */ + if (ctrl->xfer.dir == QSPI_READ && (dma_len_sg & 0x03)) { + dev_warn_once(ctrl->dev, "fallback to PIO for read of size %#010x\n", + dma_len_sg); + return -EAGAIN; + } } for (i = 0; i < sgt->nents; i++) { |