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/*
* Copyright (C) 2010 NVIDIA Corporation.
* Copyright (C) 2010 Google, Inc.
*
* This software is licensed under the terms of the GNU General Public
* License version 2, as published by the Free Software Foundation, and
* may be copied, distributed, and modified under those terms.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
*/
#include <linux/kernel.h>
#include <linux/io.h>
#include <linux/dma-mapping.h>
#include <linux/spinlock.h>
#include <linux/completion.h>
#include <linux/sched.h>
#include <linux/mutex.h>
#include <mach/dma.h>
#include <mach/iomap.h>
#include "apbio.h"
static DEFINE_MUTEX(tegra_apb_dma_lock);
static struct tegra_dma_channel *tegra_apb_dma;
static u32 *tegra_apb_bb;
static dma_addr_t tegra_apb_bb_phys;
static DECLARE_COMPLETION(tegra_apb_wait);
bool tegra_apb_init(void)
{
struct tegra_dma_channel *ch;
mutex_lock(&tegra_apb_dma_lock);
/* Check to see if we raced to setup */
if (tegra_apb_dma)
goto out;
ch = tegra_dma_allocate_channel(TEGRA_DMA_MODE_ONESHOT |
TEGRA_DMA_SHARED);
if (!ch)
goto out_fail;
tegra_apb_bb = dma_alloc_coherent(NULL, sizeof(u32),
&tegra_apb_bb_phys, GFP_KERNEL);
if (!tegra_apb_bb) {
pr_err("%s: can not allocate bounce buffer\n", __func__);
tegra_dma_free_channel(ch);
goto out_fail;
}
tegra_apb_dma = ch;
out:
mutex_unlock(&tegra_apb_dma_lock);
return true;
out_fail:
mutex_unlock(&tegra_apb_dma_lock);
return false;
}
static void apb_dma_complete(struct tegra_dma_req *req)
{
complete(&tegra_apb_wait);
}
u32 tegra_apb_readl(unsigned long offset)
{
struct tegra_dma_req req;
int ret;
if (!tegra_apb_dma && !tegra_apb_init())
return readl(IO_TO_VIRT(offset));
mutex_lock(&tegra_apb_dma_lock);
req.complete = apb_dma_complete;
req.to_memory = 1;
req.dest_addr = tegra_apb_bb_phys;
req.dest_bus_width = 32;
req.dest_wrap = 1;
req.source_addr = offset;
req.source_bus_width = 32;
req.source_wrap = 4;
req.req_sel = TEGRA_DMA_REQ_SEL_CNTR;
req.size = 4;
INIT_COMPLETION(tegra_apb_wait);
tegra_dma_enqueue_req(tegra_apb_dma, &req);
ret = wait_for_completion_timeout(&tegra_apb_wait,
msecs_to_jiffies(50));
if (WARN(ret == 0, "apb read dma timed out")) {
tegra_dma_dequeue_req(tegra_apb_dma, &req);
*(u32 *)tegra_apb_bb = 0;
}
mutex_unlock(&tegra_apb_dma_lock);
return *((u32 *)tegra_apb_bb);
}
void tegra_apb_writel(u32 value, unsigned long offset)
{
struct tegra_dma_req req;
int ret;
if (!tegra_apb_dma && !tegra_apb_init()) {
writel(value, IO_TO_VIRT(offset));
return;
}
mutex_lock(&tegra_apb_dma_lock);
*((u32 *)tegra_apb_bb) = value;
req.complete = apb_dma_complete;
req.to_memory = 0;
req.dest_addr = offset;
req.dest_wrap = 4;
req.dest_bus_width = 32;
req.source_addr = tegra_apb_bb_phys;
req.source_bus_width = 32;
req.source_wrap = 1;
req.req_sel = TEGRA_DMA_REQ_SEL_CNTR;
req.size = 4;
INIT_COMPLETION(tegra_apb_wait);
tegra_dma_enqueue_req(tegra_apb_dma, &req);
ret = wait_for_completion_timeout(&tegra_apb_wait,
msecs_to_jiffies(50));
if (WARN(ret == 0, "apb write dma timed out"))
tegra_dma_dequeue_req(tegra_apb_dma, &req);
mutex_unlock(&tegra_apb_dma_lock);
}
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