Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1243391 > unrolled thread

[PATCH 0/4] serial: tegra: One fix and a few clean-ups

Back to article view | Back to linux.kernel

Contents

  [PATCH 0/4] serial: tegra: One fix and a few clean-ups Jon Hunter <jonathanh@nvidia.com> - 2015-10-09 16:00 +0200
    [PATCH 4/4] serial: tegra: Add helper function for handling RX buffer Jon Hunter <jonathanh@nvidia.com> - 2015-10-09 16:00 +0200

#1243391 — [PATCH 0/4] serial: tegra: One fix and a few clean-ups

Fix a race condition in the receive path and simplify/clean-up the
serial-tegra driver.

This has been tested on a tegra124 by using zmodem protocol to transfer a
file from PC to the tegra device and verifying the downloaded file matches
the original.

Jon Hunter (4):
  serial: tegra: Handle another RX race condition
  serial: tegra: Remove unnecessary return statements
  serial: tegra: Remove redundant code and check in tegra_uart_stop_rx()
  serial: tegra: Add helper function for handling RX buffer

 drivers/tty/serial/serial-tegra.c | 94 ++++++++++++---------------------------
 1 file changed, 28 insertions(+), 66 deletions(-)

-- 
2.1.4

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[toc] | [next] | [standalone]

#1243395 — [PATCH 4/4] serial: tegra: Add helper function for handling RX buffer

In the tegra UART driver there are three places where the RX DMA buffer
is handled and pushed up to the tty layer. In all three instances the
same functions are called and so instead of duplicating the code in three
places, move this code to a new helper function and use this new function.

Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
---
 drivers/tty/serial/serial-tegra.c | 66 ++++++++++++++-------------------------
 1 file changed, 24 insertions(+), 42 deletions(-)

diff --git a/drivers/tty/serial/serial-tegra.c b/drivers/tty/serial/serial-tegra.c
index 11aa5e1e3705..1d6fc60ed013 100644
--- a/drivers/tty/serial/serial-tegra.c
+++ b/drivers/tty/serial/serial-tegra.c
@@ -569,13 +569,30 @@ static void tegra_uart_copy_rx_to_tty(struct tegra_uart_port *tup,
 				TEGRA_UART_RX_DMA_BUFFER_SIZE, DMA_TO_DEVICE);
 }
 
+static void tegra_uart_rx_buffer_push(struct tegra_uart_port *tup,
+				      unsigned int residue)
+{
+	struct tty_port *port = &tup->uport.state->port;
+	struct tty_struct *tty = tty_port_tty_get(port);
+	unsigned int count;
+
+	async_tx_ack(tup->rx_dma_desc);
+	count = tup->rx_bytes_requested - residue;
+
+	/* If we are here, DMA is stopped */
+	tegra_uart_copy_rx_to_tty(tup, port, count);
+
+	tegra_uart_handle_rx_pio(tup, port);
+	if (tty) {
+		tty_flip_buffer_push(port);
+		tty_kref_put(tty);
+	}
+}
+
 static void tegra_uart_rx_dma_complete(void *args)
 {
 	struct tegra_uart_port *tup = args;
 	struct uart_port *u = &tup->uport;
-	unsigned int count = tup->rx_bytes_requested;
-	struct tty_struct *tty = tty_port_tty_get(&tup->uport.state->port);
-	struct tty_port *port = &u->state->port;
 	unsigned long flags;
 	struct dma_tx_state state;
 	enum dma_status status;
@@ -589,20 +606,11 @@ static void tegra_uart_rx_dma_complete(void *args)
 		goto done;
 	}
 
-	async_tx_ack(tup->rx_dma_desc);
-
 	/* Deactivate flow control to stop sender */
 	if (tup->rts_active)
 		set_rts(tup, false);
 
-	/* If we are here, DMA is stopped */
-	tegra_uart_copy_rx_to_tty(tup, port, count);
-
-	tegra_uart_handle_rx_pio(tup, port);
-	if (tty) {
-		tty_flip_buffer_push(port);
-		tty_kref_put(tty);
-	}
+	tegra_uart_rx_buffer_push(tup, 0);
 	tegra_uart_start_rx_dma(tup);
 
 	/* Activate flow control to start transfer */
@@ -616,27 +624,14 @@ done:
 static void tegra_uart_handle_rx_dma(struct tegra_uart_port *tup)
 {
 	struct dma_tx_state state;
-	struct tty_struct *tty = tty_port_tty_get(&tup->uport.state->port);
-	struct tty_port *port = &tup->uport.state->port;
-	unsigned int count;
 
 	/* Deactivate flow control to stop sender */
 	if (tup->rts_active)
 		set_rts(tup, false);
 
 	dmaengine_terminate_all(tup->rx_dma_chan);
-	dmaengine_tx_status(tup->rx_dma_chan,  tup->rx_cookie, &state);
-	async_tx_ack(tup->rx_dma_desc);
-	count = tup->rx_bytes_requested - state.residue;
-
-	/* If we are here, DMA is stopped */
-	tegra_uart_copy_rx_to_tty(tup, port, count);
-
-	tegra_uart_handle_rx_pio(tup, port);
-	if (tty) {
-		tty_flip_buffer_push(port);
-		tty_kref_put(tty);
-	}
+	dmaengine_tx_status(tup->rx_dma_chan, tup->rx_cookie, &state);
+	tegra_uart_rx_buffer_push(tup, state.residue);
 	tegra_uart_start_rx_dma(tup);
 
 	if (tup->rts_active)
@@ -755,11 +750,8 @@ static irqreturn_t tegra_uart_isr(int irq, void *data)
 static void tegra_uart_stop_rx(struct uart_port *u)
 {
 	struct tegra_uart_port *tup = to_tegra_uport(u);
-	struct tty_struct *tty;
-	struct tty_port *port = &u->state->port;
 	struct dma_tx_state state;
 	unsigned long ier;
-	int count;
 
 	if (tup->rts_active)
 		set_rts(tup, false);
@@ -767,8 +759,6 @@ static void tegra_uart_stop_rx(struct uart_port *u)
 	if (!tup->rx_in_progress)
 		return;
 
-	tty = tty_port_tty_get(&tup->uport.state->port);
-
 	tegra_uart_wait_sym_time(tup, 1); /* wait a character interval */
 
 	ier = tup->ier_shadow;
@@ -779,15 +769,7 @@ static void tegra_uart_stop_rx(struct uart_port *u)
 	tup->rx_in_progress = 0;
 	dmaengine_terminate_all(tup->rx_dma_chan);
 	dmaengine_tx_status(tup->rx_dma_chan, tup->rx_cookie, &state);
-	async_tx_ack(tup->rx_dma_desc);
-	count = tup->rx_bytes_requested - state.residue;
-	tegra_uart_copy_rx_to_tty(tup, port, count);
-	tegra_uart_handle_rx_pio(tup, port);
-
-	if (tty) {
-		tty_flip_buffer_push(port);
-		tty_kref_put(tty);
-	}
+	tegra_uart_rx_buffer_push(tup, state.residue);
 }
 
 static void tegra_uart_hw_deinit(struct tegra_uart_port *tup)
-- 
2.1.4

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[toc] | [prev] | [standalone]

Back to top | Article view | linux.kernel

csiph-web