[ARM/tegra] dma: add transfer count query, correct spelling of CONTINUOUS

add an API to return the completed transfer count of a pending, active
or finished DMA request

CONTINUOUS was misspelled CONTINOUS; fix this in the hsuart and dma drivers

Change-Id: I732396f60f876c92fe3b74ad1d2fc02d00868d24

3 files changed, 79 insertions, 33 deletions

diff --git a/arch/arm/mach-tegra/dma.c b/arch/arm/mach-tegra/dma.c
index 423db61998a2..43f8622ee12f 100644
--- a/arch/arm/mach-tegra/dma.c
+++ b/arch/arm/mach-tegra/dma.c
@@ -95,8 +95,9 @@
 #define APB_SEQ_WRAP_SHIFT			16
 #define APB_SEQ_WRAP_MASK			(0x7<<APB_SEQ_WRAP_SHIFT)
 
+#define TEGRA_SYSTEM_DMA_AVP_CH_NUM		3
 #define TEGRA_SYSTEM_DMA_CH_MIN			0
-#define TEGRA_SYSTEM_DMA_CH_MAX			15
+#define TEGRA_SYSTEM_DMA_CH_MAX			(15 - TEGRA_SYSTEM_DMA_AVP_CH_NUM)
 
 #define NV_DMA_MAX_TRASFER_SIZE 0x10000
 
@@ -193,18 +194,81 @@ int tegra_dma_cancel(struct tegra_dma_channel *ch)
 	return 0;
 }
 
+/* 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;
+
+	/* Get the transfer count */
+	status = readl(ch->addr + APB_DMA_CHAN_STA);
+	to_transfer = (status & STA_COUNT_MASK) >> STA_COUNT_SHIFT;
+	req_transfer_count = (ch->csr & CSR_WCOUNT_MASK) >> CSR_WCOUNT_SHIFT;
+	req_transfer_count += 1;
+	to_transfer += 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.
+	 *
+	 *	FIXME: There can be a race here. What if the req to
+	 *	dequue happens at the same time as the DMA just moved to
+	 *	the new buffer and SW didn't yet received the interrupt?
+	 */
+	if (ch->mode & TEGRA_DMA_MODE_CONTINUOUS)
+		if (req->buffer_status == TEGRA_DMA_REQ_BUF_STATUS_HALF_FULL)
+			bytes_transferred += req_transfer_count;
+
+	bytes_transferred *= 4;
+
+	return bytes_transferred;
+}
+
+unsigned int tegra_dma_transferred_req(struct tegra_dma_channel *ch,
+       struct tegra_dma_req *req)
+{
+	unsigned long irq_flags;
+	unsigned int bytes_transferred;
+
+	spin_lock_irqsave(&ch->lock, irq_flags);
+
+	if (list_entry(ch->list.next, struct tegra_dma_req, node)!=req) {
+		spin_unlock_irqrestore(&ch->lock, irq_flags);
+		return req->bytes_transferred;
+	}
+
+	bytes_transferred = dma_active_count(ch, req);
+
+	spin_unlock_irqrestore(&ch->lock, irq_flags);
+
+	return bytes_transferred;
+}
+EXPORT_SYMBOL(tegra_dma_transferred_req);
+
 int tegra_dma_dequeue_req(struct tegra_dma_channel *ch,
 	struct tegra_dma_req *_req)
 {
-	unsigned int csr;
-	unsigned int status;
 	struct tegra_dma_req *req = NULL;
 	int found = 0;
+	unsigned int csr;
 	unsigned long irq_flags;
-	int to_transfer;
-	int req_transfer_count;
+	int stop = 0;
 
 	spin_lock_irqsave(&ch->lock, irq_flags);
+
+	if (list_entry(ch->list.next, struct tegra_dma_req, node)==_req)
+		stop = 1;
+
 	list_for_each_entry(req, &ch->list, node) {
 		if (req == _req) {
 			list_del(&req->node);
@@ -217,6 +281,9 @@ int tegra_dma_dequeue_req(struct tegra_dma_channel *ch,
 		return 0;
 	}
 
+	if (!stop)
+		goto skip_status;
+
 	/* STOP the DMA and get the transfer count.
 	 * Getting the transfer count is tricky.
 	 *  - Change the source selector to invalid to stop the DMA from
@@ -234,31 +301,7 @@ int tegra_dma_dequeue_req(struct tegra_dma_channel *ch,
 	csr |= CSR_ENB;
 	writel(csr, ch->addr + APB_DMA_CHAN_CSR);
 
-	/* Get the transfer count */
-	status = readl(ch->addr + APB_DMA_CHAN_STA);
-	to_transfer = (status & STA_COUNT_MASK) >> STA_COUNT_SHIFT;
-	req_transfer_count = (ch->csr & CSR_WCOUNT_MASK) >> CSR_WCOUNT_SHIFT;
-	req_transfer_count += 1;
-	to_transfer += 1;
-
-	req->bytes_transferred = req_transfer_count;
-
-	if (status & STA_BUSY)
-		req->bytes_transferred -= to_transfer;
-
-	/* In continous 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.
-	 *
-	 *	FIXME: There can be a race here. What if the req to
-	 *	dequue happens at the same time as the DMA just moved to
-	 *	the new buffer and SW didn't yet received the interrupt?
-	 */
-	if (ch->mode & TEGRA_DMA_MODE_CONTINOUS)
-		if (req->buffer_status == TEGRA_DMA_REQ_BUF_STATUS_HALF_FULL)
-			req->bytes_transferred += req_transfer_count;
-
-	req->bytes_transferred *= 4;
+	req->bytes_transferred = dma_active_count(ch, req);
 
 	tegra_dma_stop(ch);
 	if (!list_empty(&ch->list)) {
@@ -268,6 +311,7 @@ int tegra_dma_dequeue_req(struct tegra_dma_channel *ch,
 			typeof(*next_req), node);
 		tegra_dma_update_hw(ch, next_req);
 	}
+skip_status:
 	req->status = -TEGRA_DMA_REQ_ERROR_ABORTED;
 
 	spin_unlock_irqrestore(&ch->lock, irq_flags);
diff --git a/arch/arm/mach-tegra/include/mach/dma.h b/arch/arm/mach-tegra/include/mach/dma.h
index 59f734038ea9..731b433812a9 100644
--- a/arch/arm/mach-tegra/include/mach/dma.h
+++ b/arch/arm/mach-tegra/include/mach/dma.h
@@ -58,7 +58,7 @@ struct tegra_dma_channel;
 
 enum tegra_dma_mode {
 	TEGRA_DMA_SHARED = 1,
-	TEGRA_DMA_MODE_CONTINOUS = 2,
+	TEGRA_DMA_MODE_CONTINUOUS = 2,
 	TEGRA_DMA_MODE_ONESHOT = 4,
 };
 
@@ -75,7 +75,6 @@ enum tegra_dma_req_buff_status {
 
 struct tegra_dma_req {
 	struct list_head node;
-	unsigned int modid;
 	int instance;
 
 	/* Called when the req is complete and from the DMA ISR context.
@@ -140,6 +139,9 @@ int tegra_dma_dequeue_req(struct tegra_dma_channel *ch,
 void tegra_dma_dequeue(struct tegra_dma_channel *ch);
 void tegra_dma_flush(struct tegra_dma_channel *ch);
 
+unsigned int tegra_dma_transferred_req(struct tegra_dma_channel *ch,
+	struct tegra_dma_req *req);
+
 bool tegra_dma_is_req_inflight(struct tegra_dma_channel *ch,
 	struct tegra_dma_req *req);
 bool tegra_dma_is_empty(struct tegra_dma_channel *ch);
diff --git a/drivers/serial/tegra_hsuart.c b/drivers/serial/tegra_hsuart.c
index f3a03e44947b..94c6ddb1bb1b 100644
--- a/drivers/serial/tegra_hsuart.c
+++ b/drivers/serial/tegra_hsuart.c
@@ -642,7 +642,7 @@ static int tegra_uart_init_rx_dma(struct tegra_uart_port *t)
 	dma_addr_t rx_dma_phys;
 	void *rx_dma_virt;
 
-	t->rx_dma = tegra_dma_allocate_channel(TEGRA_DMA_MODE_CONTINOUS);
+	t->rx_dma = tegra_dma_allocate_channel(TEGRA_DMA_MODE_CONTINUOUS);
 	if (IS_ERR_OR_NULL(t->rx_dma))
 		return -ENODEV;