diff options
| author | Daniel Kurtz <djkurtz@chromium.org> | 2017-01-27 00:21:53 +0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-07-05 14:40:28 +0200 |
| commit | c52829f60f5f6e228a70162717df199e874898a8 (patch) | |
| tree | 04c7807564c4dfdb7763c3459626651b6a48fc0f | |
| parent | 478273e11521915b7a0fd977b4d43587997ec7b2 (diff) | |
spi: When no dma_chan map buffers with spi_master's parent
commit 88b0aa544af58ce3be125a1845a227264ec9ab89 upstream.
Back before commit 1dccb598df54 ("arm64: simplify dma_get_ops"), for
arm64, devices for which dma_ops were not explicitly set were automatically
configured to use swiotlb_dma_ops, since this was hard-coded as the
global "dma_ops" in arm64_dma_init().
Now that global "dma_ops" has been removed, all devices much have their
dma_ops explicitly set by a call to arch_setup_dma_ops(), otherwise the
device is assigned dummy_dma_ops, and thus calls to map_sg for such a
device will fail (return 0).
Mediatek SPI uses DMA but does not use a dma channel. Support for this
was added by commit c37f45b5f1cd ("spi: support spi without dma channel
to use can_dma()"), which uses the master_spi dev to DMA map buffers.
The master_spi device is not a platform device, rather it is created
in spi_alloc_device(), and therefore its dma_ops are never set.
Therefore, when the mediatek SPI driver when it does DMA (for large SPI
transactions > 32 bytes), SPI will use spi_map_buf()->dma_map_sg() to
map the buffer for use in DMA. But dma_map_sg()->dma_map_sg_attrs() returns
0, because ops->map_sg is dummy_dma_ops->__dummy_map_sg, and hence
spi_map_buf() returns -ENOMEM (-12).
Fix this by using the real spi_master's parent device which should be a
real physical device with DMA properties.
Signed-off-by: Daniel Kurtz <djkurtz@chromium.org>
Fixes: c37f45b5f1cd ("spi: support spi without dma channel to use can_dma()")
Cc: Leilk Liu <leilk.liu@mediatek.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/spi/spi.c | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index 24d4492d0168..ddc39b4fe3d8 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -797,12 +797,12 @@ static int __spi_map_msg(struct spi_master *master, struct spi_message *msg) if (master->dma_tx) tx_dev = master->dma_tx->device->dev; else - tx_dev = &master->dev; + tx_dev = master->dev.parent; if (master->dma_rx) rx_dev = master->dma_rx->device->dev; else - rx_dev = &master->dev; + rx_dev = master->dev.parent; list_for_each_entry(xfer, &msg->transfers, transfer_list) { if (!master->can_dma(master, msg->spi, xfer)) @@ -844,12 +844,12 @@ static int __spi_unmap_msg(struct spi_master *master, struct spi_message *msg) if (master->dma_tx) tx_dev = master->dma_tx->device->dev; else - tx_dev = &master->dev; + tx_dev = master->dev.parent; if (master->dma_rx) rx_dev = master->dma_rx->device->dev; else - rx_dev = &master->dev; + rx_dev = master->dev.parent; list_for_each_entry(xfer, &msg->transfers, transfer_list) { if (!master->can_dma(master, msg->spi, xfer)) |