Linux-ARM-Kernel Archive on lore.kernel.org

* [PATCH v2 2/3] firmware: raspberrypi: Use correct device for DMA mappings
From: Laurent Pinchart @ 2024-03-26 19:58 UTC (permalink / raw)
  To: devicetree, linux-rpi-kernel, linux-arm-kernel
  Cc: Dave Stevenson, Naushir Patuck,
	Broadcom internal kernel review list, Conor Dooley,
	Florian Fainelli, Krzysztof Kozlowski, Nicolas Saenz Julienne,
	Ray Jui, Rob Herring, Scott Branden, Stefan Wahren
In-Reply-To: <20240326195807.15163-1-laurent.pinchart@ideasonboard.com>

The buffer used to transfer data over the mailbox interface is mapped
using the client's device. This is incorrect, as the device performing
the DMA transfer is the mailbox itself. Fix it by using the mailbox
controller device instead.

This requires including the mailbox_controller.h header to dereference
the mbox_chan and mbox_controller structures. The header is not meant to
be included by clients. This could be fixed by extending the client API
with a function to access the controller's device.

Fixes: 4e3d60656a72 ("ARM: bcm2835: Add the Raspberry Pi firmware driver")
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
---
 drivers/firmware/raspberrypi.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/firmware/raspberrypi.c b/drivers/firmware/raspberrypi.c
index 322aada20f74..ac34876a97f8 100644
--- a/drivers/firmware/raspberrypi.c
+++ b/drivers/firmware/raspberrypi.c
@@ -9,6 +9,7 @@
 #include <linux/dma-mapping.h>
 #include <linux/kref.h>
 #include <linux/mailbox_client.h>
+#include <linux/mailbox_controller.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_platform.h>
@@ -97,8 +98,8 @@ int rpi_firmware_property_list(struct rpi_firmware *fw,
 	if (size & 3)
 		return -EINVAL;
 
-	buf = dma_alloc_coherent(fw->cl.dev, PAGE_ALIGN(size), &bus_addr,
-				 GFP_ATOMIC);
+	buf = dma_alloc_coherent(fw->chan->mbox->dev, PAGE_ALIGN(size),
+				 &bus_addr, GFP_ATOMIC);
 	if (!buf)
 		return -ENOMEM;
 
@@ -126,7 +127,7 @@ int rpi_firmware_property_list(struct rpi_firmware *fw,
 		ret = -EINVAL;
 	}
 
-	dma_free_coherent(fw->cl.dev, PAGE_ALIGN(size), buf, bus_addr);
+	dma_free_coherent(fw->chan->mbox->dev, PAGE_ALIGN(size), buf, bus_addr);
 
 	return ret;
 }
-- 
Regards,

Laurent Pinchart


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