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[3/3] of/platform: initialise AMBA default DMA masks

Message ID 20180829062401.8701-4-hch@lst.de
State Accepted
Commit 8c89ef7b6b64ba093239305f77a485905d03f7bf
Headers show
Series None | expand

Commit Message

Christoph Hellwig Aug. 29, 2018, 6:24 a.m. UTC 
From: Linus Walleij <linus.walleij@linaro.org>


commit a5516219b102 ("of/platform: Initialise default DMA masks") sets up
the coherent_dma_mask of platform devices created from the device tree,
but fails to do the same for AMBA (PrimeCell) devices.

This leads to a regression in kernel v4.19-rc1 triggering the
WARN_ON_ONCE(dev && !dev->coherent_dma_mask) in dma_alloc_attrs().

This regresses the PL111 DRM driver in drivers/gpu/drm/pl111 that uses
the AMBA PrimeCell to instantiate the frame buffer device, as it cannot
allocate a chunk of coherent memory anymore due to the missing mask.

Fixes: a5516219b102 ("of/platform: Initialise default DMA masks")
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

[hch: added a comment, and droped a conditional that can't be true]
Signed-off-by: Christoph Hellwig <hch@lst.de>

---
 drivers/of/platform.c | 4 ++++
 1 file changed, 4 insertions(+)

-- 
2.18.0
diff mbox series

Patch

diff --git a/drivers/of/platform.c b/drivers/of/platform.c
index 7ba90c290a42..6c59673933e9 100644
--- a/drivers/of/platform.c
+++ b/drivers/of/platform.c
@@ -241,6 +241,10 @@  static struct amba_device *of_amba_device_create(struct device_node *node,
 	if (!dev)
 		goto err_clear_flag;
 
+	/* AMBA devices only support a single DMA mask */
+	dev->dev.coherent_dma_mask = DMA_BIT_MASK(32);
+	dev->dev.dma_mask = &dev->dev.coherent_dma_mask;
+
 	/* setup generic device info */
 	dev->dev.of_node = of_node_get(node);
 	dev->dev.fwnode = &node->fwnode;