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[RFC,5.10.y-cip,08/39] of: also handle dma-noncoherent in of_dma_is_coherent()

Message ID 20240130203346.94488-9-prabhakar.mahadev-lad.rj@bp.renesas.com (mailing list archive)
State New
Headers show
Series Add support for Renesas RZ/Five RISC-V SoC | expand

Commit Message

Lad Prabhakar Jan. 30, 2024, 8:33 p.m. UTC 
From: Heiko Stuebner <heiko@sntech.de>

commit 12b827758f51d4b614a677dd453b0e854e46aa65 upstream.

of_dma_is_coherent() currently expects the architecture to be
non-coherent and some devices being coherent getting marked
as such with the dma-coherent devicetree property.

For PowerPC CONFIG_OF_DMA_DEFAULT_COHERENT was added which currently
makes of_dma_is_coherent() always return true but doesn't handle
the case of the architecture being coherent but some devices not.

So modify the function to also check for dma-noncoherent and
set a suitable default return value. If CONFIG_OF_DMA_DEFAULT_COHERENT
is set the value starts with true and finding dma-noncoherent will
set it to false and without CONFIG_OF_DMA_DEFAULT_COHERENT, the
behaviour is reversed.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Rob Herring <robh@kernel.org>
Reviewed-by: Guo Ren <guoren@kernel.org>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Link: https://lore.kernel.org/r/20220706231536.2041855-2-heiko@sntech.de
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
---
 drivers/of/address.c | 17 ++++++++++-------
 1 file changed, 10 insertions(+), 7 deletions(-)
diff mbox series

Patch

diff --git a/drivers/of/address.c b/drivers/of/address.c
index f686fb5011b87..557a4be011034 100644
--- a/drivers/of/address.c
+++ b/drivers/of/address.c
@@ -1081,25 +1081,28 @@  phys_addr_t __init of_dma_get_max_cpu_address(struct device_node *np)
  *
  * It returns true if "dma-coherent" property was found
  * for this device in the DT, or if DMA is coherent by
- * default for OF devices on the current platform.
+ * default for OF devices on the current platform and no
+ * "dma-noncoherent" property was found for this device.
  */
 bool of_dma_is_coherent(struct device_node *np)
 {
 	struct device_node *node;
-
-	if (IS_ENABLED(CONFIG_OF_DMA_DEFAULT_COHERENT))
-		return true;
+	bool is_coherent = IS_ENABLED(CONFIG_OF_DMA_DEFAULT_COHERENT);
 
 	node = of_node_get(np);
 
 	while (node) {
 		if (of_property_read_bool(node, "dma-coherent")) {
-			of_node_put(node);
-			return true;
+			is_coherent = true;
+			break;
+		}
+		if (of_property_read_bool(node, "dma-noncoherent")) {
+			is_coherent = false;
+			break;
 		}
 		node = of_get_next_dma_parent(node);
 	}
 	of_node_put(node);
-	return false;
+	return is_coherent;
 }
 EXPORT_SYMBOL_GPL(of_dma_is_coherent);