[PATCH v2 2/4] dmaengine: sh: rcar-dmac: SMMU doesn't need IPMMU workaround
From: Wolfram Sang <wsa+renesas@sang-engineering.com>
Date: 2026-09-09 09:40:53
Also in:
dmaengine
Subsystem:
dma generic offload engine subsystem, the rest · Maintainers:
Vinod Koul, Linus Torvalds
R-Car Gen5 doesn't use an IPMMU anymore, but a SMMU. So, the workaround for the IPMMU becomes optional. Add a flag to distinguish. No functional change. Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com> Reviewed-by: Frank Li <Frank.Li@nxp.com> --- Changes since v1: * tags added (Thanks Frank) * renamed the flag-variable (Thanks Geert) * added a comment that Gen4 might not be affected drivers/dma/sh/rcar-dmac.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/drivers/dma/sh/rcar-dmac.c b/drivers/dma/sh/rcar-dmac.c
index cf07c17847d0..4eca52aeec02 100644
--- a/drivers/dma/sh/rcar-dmac.c
+++ b/drivers/dma/sh/rcar-dmac.c@@ -219,10 +219,12 @@ struct rcar_dmac { * struct rcar_dmac_of_data - This driver's OF data * @chan_offset_base: DMAC channels base offset * @chan_offset_stride: DMAC channels offset stride + * @broken_ipmmu_microTLB0: flag if the connected IPMMU has microTLB0 issues */ struct rcar_dmac_of_data { u32 chan_offset_base; u32 chan_offset_stride; + unsigned int broken_ipmmu_microTLB0:1; }; /* -----------------------------------------------------------------------------
@@ -1877,8 +1879,9 @@ static int rcar_dmac_probe(struct platform_device *pdev) * 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. + * Not applicable if system uses something else than IPMMU like SMMU. */ - if (device_iommu_mapped(&pdev->dev)) + if (data->broken_ipmmu_microTLB0 && device_iommu_mapped(&pdev->dev)) dmac->channels_mask &= ~BIT(0); dmac->channels = devm_kcalloc(&pdev->dev, dmac->n_channels,
@@ -2000,11 +2003,14 @@ static void rcar_dmac_shutdown(struct platform_device *pdev) static const struct rcar_dmac_of_data rcar_dmac_data = { .chan_offset_base = 0x8000, .chan_offset_stride = 0x80, + .broken_ipmmu_microTLB0 = 1, }; static const struct rcar_dmac_of_data rcar_gen4_dmac_data = { .chan_offset_base = 0x0, .chan_offset_stride = 0x1000, + /* Set to play safe. Needs testing if Gen4 is really affected */ + .broken_ipmmu_microTLB0 = 1, }; static const struct of_device_id rcar_dmac_of_ids[] = {
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2.53.0