From 9295f238a52a566f45f9b1752bebd93b4c2d83a2 Mon Sep 17 00:00:00 2001 From: Akhil R Date: Mon, 18 May 2026 17:10:10 +0530 Subject: [PATCH] i2c: tegra: use dmaengine_get_dma_device() for DMA buffer allocation Use dmaengine_get_dma_device() to obtain the correct struct device pointer for dma_alloc_coherent() instead of directly dereferencing chan->device->dev. The dmaengine_get_dma_device() helper checks whether the DMA channel has a per-channel DMA device (chan->dev->chan_dma_dev) and returns it when available, falling back to the controller device otherwise. On platforms where the DMA controller sits behind an IOMMU with per-channel IOVA spaces (e.g. Tegra264 GPC DMA), the per-channel device carries the correct DMA mapping context. Using the controller device directly would allocate DMA buffers against the wrong IOMMU domain, leading to SMMU faults at runtime. On platforms without per-channel DMA devices the helper returns the same pointer as before, so there is no change in behavior for existing hardware. Assisted-by: Cursor:claude-4.6-opus Signed-off-by: Akhil R Reviewed-by: Jon Hunter Signed-off-by: Andi Shyti Link: https://lore.kernel.org/r/20260518114013.62065-2-akhilrajeev@nvidia.com --- drivers/i2c/busses/i2c-tegra.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c index 3e9327e3750a..a6859059a2e8 100644 --- a/drivers/i2c/busses/i2c-tegra.c +++ b/drivers/i2c/busses/i2c-tegra.c @@ -712,7 +712,7 @@ static int tegra_i2c_init_dma(struct tegra_i2c_dev *i2c_dev) goto err_out; } - i2c_dev->dma_dev = i2c_dev->dma_chan->device->dev; + i2c_dev->dma_dev = dmaengine_get_dma_device(i2c_dev->dma_chan); i2c_dev->dma_buf_size = i2c_dev->hw->quirks->max_write_len + I2C_PACKET_HEADER_SIZE;