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Message-Id: <1453492292-17279-1-git-send-email-shraddha.6596@gmail.com>
Date: Sat, 23 Jan 2016 01:21:32 +0530
From: Shraddha Barke <shraddha.6596@...il.com>
To: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Dan Carpenter <dan.carpenter@...cle.com>,
Joe Perches <joe@...ches.com>, linux-kernel@...r.kernel.org
Cc: Peter Senna Tschudin <peter.senna@...il.com>,
Julia Lawall <julia.lawall@...6.fr>,
Shraddha Barke <shraddha.6596@...il.com>
Subject: [PATCH] Platform: goldfish: goldfish_pipe.c: Add DMA support using managed version
Function setup_access_params_addr is called only from probe function, hence
managed version dmam_alloc_coherent is used.
setup_access_params_addr has 2 goals-
-Initialize the access_params field so that it can be used to send and read
commands from the device in access_with_param
-Get a bus address for the allocated memory to transfer to the device.
Replace the combination of devm_kzalloc and _pa() with dmam_alloc_coherent.
Coherent mapping guarantees that the device and CPU are in sync.
Signed-off-by: Shraddha Barke <shraddha.6596@...il.com>
---
drivers/platform/goldfish/goldfish_pipe.c | 19 +++++++++++--------
1 file changed, 11 insertions(+), 8 deletions(-)
diff --git a/drivers/platform/goldfish/goldfish_pipe.c b/drivers/platform/goldfish/goldfish_pipe.c
index e7a29e2..fb982ac 100644
--- a/drivers/platform/goldfish/goldfish_pipe.c
+++ b/drivers/platform/goldfish/goldfish_pipe.c
@@ -57,6 +57,7 @@
#include <linux/slab.h>
#include <linux/io.h>
#include <linux/goldfish.h>
+#include <linux/dma-mapping.h>
/*
* IMPORTANT: The following constants must match the ones used and defined
@@ -217,17 +218,19 @@ static int valid_batchbuffer_addr(struct goldfish_pipe_dev *dev,
static int setup_access_params_addr(struct platform_device *pdev,
struct goldfish_pipe_dev *dev)
{
- u64 paddr;
+ dma_addr_t dma_handle;
struct access_params *aps;
- aps = devm_kzalloc(&pdev->dev, sizeof(struct access_params), GFP_KERNEL);
- if (!aps)
- return -1;
+ aps = dmam_alloc_coherent(&pdev->dev, sizeof(struct access_params),
+ &dma_handle, GFP_KERNEL);
+ if (!aps) {
+ dev_err(&pdev->dev, "allocate buffer failed\n");
+ return -ENOMEM;
+ }
- /* FIXME */
- paddr = __pa(aps);
- writel((u32)(paddr >> 32), dev->base + PIPE_REG_PARAMS_ADDR_HIGH);
- writel((u32)paddr, dev->base + PIPE_REG_PARAMS_ADDR_LOW);
+ writel((u32)((u64)dma_handle >> 32), dev->base +
+ PIPE_REG_PARAMS_ADDR_HIGH);
+ writel((u32)dma_handle, dev->base + PIPE_REG_PARAMS_ADDR_LOW);
if (valid_batchbuffer_addr(dev, aps)) {
dev->aps = aps;
--
2.1.4
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