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Staging: goldfish: goldfish_nand: Add DMA Support using dmam_alloc_coherent 

Function nand_setup_cmd_params has 2 goals-

-Initialize the cmd_params field so that it can be used to send and read
commands from the device.
-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@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Shraddha Barke 2016-01-21 02:38:53 +05:30 committed by Greg Kroah-Hartman
parent d62f324b0a
commit 3e2fbc7fee
1 changed files with 11 additions and 9 deletions
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20
drivers/staging/goldfish/goldfish_nand.c
View File

@ -27,6 +27,7 @@
#include <linux/mutex.h>
#include <linux/goldfish.h>
#include <asm/div64.h>
#include <linux/dma-mapping.h>
#include "goldfish_nand_reg.h"
@ -284,17 +285,18 @@ invalid_arg:
static int nand_setup_cmd_params(struct platform_device *pdev,
struct goldfish_nand *nand)
{
u64 paddr;
dma_addr_t dma_handle;
unsigned char __iomem *base = nand->base;
nand->cmd_params = devm_kzalloc(&pdev->dev,
sizeof(struct cmd_params), GFP_KERNEL);
if (!nand->cmd_params)
return -1;
paddr = __pa(nand->cmd_params);
writel((u32)(paddr >> 32), base + NAND_CMD_PARAMS_ADDR_HIGH);
writel((u32)paddr, base + NAND_CMD_PARAMS_ADDR_LOW);
nand->cmd_params = dmam_alloc_coherent(&pdev->dev,
sizeof(struct cmd_params),
&dma_handle, GFP_KERNEL);
if (!nand->cmd_params) {
dev_err(&pdev->dev, "allocate buffer failed\n");
return -ENOMEM;
}
writel((u32)((u64)dma_handle >> 32), base + NAND_CMD_PARAMS_ADDR_HIGH);
writel((u32)dma_handle, base + NAND_CMD_PARAMS_ADDR_LOW);
return 0;
}