[PATCH] Platform: goldfish: goldfish_pipe.c: Add DMA support using managed version

[Shraddha Barke]

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.6...@gmail.com>
---
 drivers/platform/goldfish/goldfish_pipe.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/drivers/platform/goldfish/goldfish_pipe.c 
b/drivers/platform/goldfish/goldfish_pipe.c
index e7a29e2..4b0babb 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 +218,16 @@ 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);
+       aps = dmam_alloc_coherent(&pdev->dev, sizeof(struct access_params),
+             &dma_handle, GFP_KERNEL);
        if (!aps)
-               return -1;
+               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(upper_32_bits(dma_handle), dev->base + 
PIPE_REG_PARAMS_ADDR_HIGH);
+       writel(lower_32_bits(dma_handle), dev->base + PIPE_REG_PARAMS_ADDR_LOW);
 
        if (valid_batchbuffer_addr(dev, aps)) {
                dev->aps = aps;
-- 
2.1.4