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-rw-r--r--arch/arm/mach-tegra/apbio.c145
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 0000000..e75451e
--- /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);
+}