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| author | Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com> | 2015-01-27 19:04:10 +0200 |
|---|---|---|
| committer | Vinod Koul <vinod.koul@intel.com> | 2015-02-16 09:33:35 +0530 |
| commit | be6893e1958035cbeff281b833777c5cd3fb36ad (patch) | |
| tree | 093195bbad635531be5814a8d3403aef0d557865 /drivers | |
| parent | 3f46306127bb7d8a69078ff9ef8a5827677c2159 (diff) | |
| download | linux-rpi3-be6893e1958035cbeff281b833777c5cd3fb36ad.tar.gz linux-rpi3-be6893e1958035cbeff281b833777c5cd3fb36ad.tar.bz2 linux-rpi3-be6893e1958035cbeff281b833777c5cd3fb36ad.zip | |
dmaengine: rcar-dmac: Disable channel 0 when using IOMMU
A still unconfirmed hardware bug prevents the IPMMU microTLB 0 to be
flushed correctly, resulting in memory corruption. DMAC 0 channel 0 is
connected to microTLB 0 on currently supported platforms, so we can't
use it with the IPMMU. As the IOMMU API operates at the device level we
can't disable it selectively, so ignore channel 0 for now if the device
is part of an IOMMU group.
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Acked-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/dma/sh/rcar-dmac.c | 17 |
1 files changed, 16 insertions, 1 deletions
diff --git a/drivers/dma/sh/rcar-dmac.c b/drivers/dma/sh/rcar-dmac.c index 711da01a200b..a18d16cc4795 100644 --- a/drivers/dma/sh/rcar-dmac.c +++ b/drivers/dma/sh/rcar-dmac.c @@ -1593,6 +1593,7 @@ static int rcar_dmac_probe(struct platform_device *pdev) DMA_SLAVE_BUSWIDTH_2_BYTES | DMA_SLAVE_BUSWIDTH_4_BYTES | DMA_SLAVE_BUSWIDTH_8_BYTES | DMA_SLAVE_BUSWIDTH_16_BYTES | DMA_SLAVE_BUSWIDTH_32_BYTES | DMA_SLAVE_BUSWIDTH_64_BYTES; + unsigned int channels_offset = 0; struct dma_device *engine; struct rcar_dmac *dmac; struct resource *mem; @@ -1612,6 +1613,19 @@ static int rcar_dmac_probe(struct platform_device *pdev) if (ret < 0) return ret; + /* + * A still unconfirmed hardware bug prevents the IPMMU microTLB 0 to be + * flushed correctly, resulting in memory corruption. DMAC 0 channel 0 + * is connected to microTLB 0 on currently supported platforms, so we + * can't use it with the IPMMU. As the IOMMU API operates at the device + * level we can't disable it selectively, so ignore channel 0 for now if + * the device is part of an IOMMU group. + */ + if (pdev->dev.iommu_group) { + dmac->n_channels--; + channels_offset = 1; + } + dmac->channels = devm_kcalloc(&pdev->dev, dmac->n_channels, sizeof(*dmac->channels), GFP_KERNEL); if (!dmac->channels) @@ -1662,7 +1676,8 @@ static int rcar_dmac_probe(struct platform_device *pdev) INIT_LIST_HEAD(&dmac->engine.channels); for (i = 0; i < dmac->n_channels; ++i) { - ret = rcar_dmac_chan_probe(dmac, &dmac->channels[i], i); + ret = rcar_dmac_chan_probe(dmac, &dmac->channels[i], + i + channels_offset); if (ret < 0) goto error; } |