1 files changed, 68 insertions, 3 deletions

diff --git a/arch/arm/mach-tegra/dma.c b/arch/arm/mach-tegra/dma.c
index 35499916e2bd..374d428b8779 100644
--- a/arch/arm/mach-tegra/dma.c
+++ b/arch/arm/mach-tegra/dma.c
@@ -34,6 +34,8 @@
 #include <mach/iomap.h>
 #include <mach/clk.h>
 
+#include "apbio.h"
+
 #define APB_DMA_GEN				0x000
 #define GEN_ENABLE				(1<<31)
 
@@ -355,6 +357,68 @@ static unsigned int dma_active_count(struct tegra_dma_channel *ch,
 	return bytes_transferred;
 }
 
+static unsigned int get_channel_status(struct tegra_dma_channel *ch,
+			struct tegra_dma_req *req, bool is_stop_dma)
+{
+	void __iomem *addr = IO_ADDRESS(TEGRA_APB_DMA_BASE);
+	unsigned int status;
+
+	if (is_stop_dma) {
+		/*
+		 * STOP the DMA and get the transfer count.
+		 * Getting the transfer count is tricky.
+		 *  - Globally disable DMA on all channels
+		 *  - Read the channel's status register to know the number
+		 *    of pending bytes to be transfered.
+		 *  - Stop the dma channel
+		 *  - Globally re-enable DMA to resume other transfers
+		 */
+		spin_lock(&enable_lock);
+		writel(0, addr + APB_DMA_GEN);
+		udelay(20);
+		status = readl(ch->addr + APB_DMA_CHAN_STA);
+		tegra_dma_stop(ch);
+		writel(GEN_ENABLE, addr + APB_DMA_GEN);
+		spin_unlock(&enable_lock);
+		if (status & STA_ISE_EOC) {
+			pr_err("Got Dma Int here clearing");
+			writel(status, ch->addr + APB_DMA_CHAN_STA);
+		}
+		req->status = TEGRA_DMA_REQ_ERROR_ABORTED;
+	} else {
+		status = readl(ch->addr + APB_DMA_CHAN_STA);
+	}
+	return status;
+}
+
+/* should be called with the channel lock held */
+static unsigned int dma_active_count(struct tegra_dma_channel *ch,
+	struct tegra_dma_req *req, unsigned int status)
+{
+	unsigned int to_transfer;
+	unsigned int req_transfer_count;
+	unsigned int bytes_transferred;
+
+	to_transfer = ((status & STA_COUNT_MASK) >> STA_COUNT_SHIFT) + 1;
+	req_transfer_count = ch->req_transfer_count + 1;
+	bytes_transferred = req_transfer_count;
+	if (status & STA_BUSY)
+		bytes_transferred -= to_transfer;
+	/*
+	 * In continuous transfer mode, DMA only tracks the count of the
+	 * half DMA buffer. So, if the DMA already finished half the DMA
+	 * then add the half buffer to the completed count.
+	 */
+	if (ch->mode & TEGRA_DMA_MODE_CONTINOUS) {
+		if (req->buffer_status == TEGRA_DMA_REQ_BUF_STATUS_HALF_FULL)
+			bytes_transferred += req_transfer_count;
+		if (status & STA_ISE_EOC)
+			bytes_transferred += req_transfer_count;
+	}
+	bytes_transferred *= 4;
+	return bytes_transferred;
+}
+
 int tegra_dma_dequeue_req(struct tegra_dma_channel *ch,
 	struct tegra_dma_req *_req)
 {
@@ -382,7 +446,7 @@ int tegra_dma_dequeue_req(struct tegra_dma_channel *ch,
 	}
 
 	if (!stop)
-		goto skip_status;
+		goto skip_stop_dma;
 
 	status = get_channel_status(ch, req, true);
 	req->bytes_transferred = dma_active_count(ch, req, status);
@@ -394,7 +458,8 @@ int tegra_dma_dequeue_req(struct tegra_dma_channel *ch,
 			typeof(*next_req), node);
 		tegra_dma_update_hw(ch, next_req);
 	}
-skip_status:
+
+skip_stop_dma:
 	req->status = -TEGRA_DMA_REQ_ERROR_ABORTED;
 
 	spin_unlock_irqrestore(&ch->lock, irq_flags);
@@ -557,7 +622,7 @@ struct tegra_dma_channel *tegra_dma_allocate_channel(int mode,
 	va_list args;
 	dma_isr_handler isr_handler = NULL;
 
-	if (WARN_ON(!tegra_dma_initialized))
+	if (!tegra_dma_initialized)
 		return NULL;
 
 	mutex_lock(&tegra_dma_lock);