1 files changed, 145 insertions, 0 deletions
diff --git a/arch/arm/mach-tegra/apbio.c b/arch/arm/mach-tegra/apbio.c
new file mode 100644
index 000000000000..e75451e517bd
--- /dev/null
+++ b/arch/arm/mach-tegra/apbio.c
@@ -0,0 +1,145 @@
+/*
+ * 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);
+}