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From: Bryan Wu <bryan.wu@analog.com>
To: linux-serial@vger.kernel.org
Cc: linux-kernel@vger.kernel.org,
	Sonic Zhang <sonic.zhang@analog.com>,
	Bryan Wu <bryan.wu@analog.com>
Subject: [PATCH 02/12] [Blackfin] Serial driver: Fix bug - serial driver in PIO mode cant handle input very quickly
Date: Wed, 30 Jan 2008 17:30:02 +0800	[thread overview]
Message-ID: <1201685412-29095-3-git-send-email-bryan.wu@analog.com> (raw)
In-Reply-To: <1201685412-29095-1-git-send-email-bryan.wu@analog.com>

From: Sonic Zhang <sonic.zhang@analog.com>

Output as many bytes as possible in PIO tx handler.
This reduce the number of tx interrupts and shorten the delay to handle
rx interrupt. So, rx overrun disappears.

Signed-off-by: Sonic Zhang <sonic.zhang@analog.com>
Signed-off-by: Bryan Wu <bryan.wu@analog.com>
---
 drivers/serial/bfin_5xx.c |   62 ++++++++++----------------------------------
 1 files changed, 14 insertions(+), 48 deletions(-)

diff --git a/drivers/serial/bfin_5xx.c b/drivers/serial/bfin_5xx.c
index ac2a3ef..e059475 100644
--- a/drivers/serial/bfin_5xx.c
+++ b/drivers/serial/bfin_5xx.c
@@ -74,7 +74,6 @@ static void bfin_serial_dma_tx_chars(struct bfin_serial_port *uart);
 #else
 static void bfin_serial_do_work(struct work_struct *work);
 static void bfin_serial_tx_chars(struct bfin_serial_port *uart);
-static void local_put_char(struct bfin_serial_port *uart, char ch);
 #endif
 
 static void bfin_serial_mctrl_check(struct bfin_serial_port *uart);
@@ -85,6 +84,9 @@ static void bfin_serial_mctrl_check(struct bfin_serial_port *uart);
 static void bfin_serial_stop_tx(struct uart_port *port)
 {
 	struct bfin_serial_port *uart = (struct bfin_serial_port *)port;
+#ifndef CONFIG_BF54x
+	unsigned short ier;
+#endif
 
 	while (!(UART_GET_LSR(uart) & TEMT))
 		continue;
@@ -100,8 +102,6 @@ static void bfin_serial_stop_tx(struct uart_port *port)
 	UART_PUT_LSR(uart, TFI);
 	UART_CLEAR_IER(uart, ETBEI);
 #else
-	unsigned short ier;
-
 	ier = UART_GET_IER(uart);
 	ier &= ~ETBEI;
 	UART_PUT_IER(uart, ier);
@@ -210,23 +210,6 @@ int kgdb_get_debug_char(void)
 #endif
 
 #ifdef CONFIG_SERIAL_BFIN_PIO
-static void local_put_char(struct bfin_serial_port *uart, char ch)
-{
-	unsigned short status;
-	int flags = 0;
-
-	spin_lock_irqsave(&uart->port.lock, flags);
-
-	do {
-		status = UART_GET_LSR(uart);
-	} while (!(status & THRE));
-
-	UART_PUT_CHAR(uart, ch);
-	SSYNC();
-
-	spin_unlock_irqrestore(&uart->port.lock, flags);
-}
-
 static void bfin_serial_rx_chars(struct bfin_serial_port *uart)
 {
 	struct tty_struct *tty = uart->port.info->tty;
@@ -236,8 +219,8 @@ static void bfin_serial_rx_chars(struct bfin_serial_port *uart)
 	struct pt_regs *regs = get_irq_regs();
 #endif
 
-	status = UART_GET_LSR(uart);
  	ch = UART_GET_CHAR(uart);
+	status = UART_GET_LSR(uart);
  	uart->port.icount.rx++;
 
 #ifdef CONFIG_KGDB_UART
@@ -337,9 +320,12 @@ static void bfin_serial_tx_chars(struct bfin_serial_port *uart)
 		return;
 	}
 
-	local_put_char(uart, xmit->buf[xmit->tail]);
-	xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
-	uart->port.icount.tx++;
+	while ((UART_GET_LSR(uart) & THRE) && xmit->tail != xmit->head) {
+		UART_PUT_CHAR(uart, xmit->buf[xmit->tail]);
+		xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
+		uart->port.icount.tx++;
+		SSYNC();
+	}
 
 	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
 		uart_write_wakeup(&uart->port);
@@ -352,21 +338,11 @@ static irqreturn_t bfin_serial_rx_int(int irq, void *dev_id)
 {
 	struct bfin_serial_port *uart = dev_id;
 
-#ifdef CONFIG_BF54x
-	unsigned short status;
 	spin_lock(&uart->port.lock);
-	status = UART_GET_LSR(uart);
-	while ((UART_GET_IER(uart) & ERBFI) && (status & DR)) {
+	while ((UART_GET_IER(uart) & ERBFI) && (UART_GET_LSR(uart) & DR))
 		bfin_serial_rx_chars(uart);
-		status = UART_GET_LSR(uart);
-	}
 	spin_unlock(&uart->port.lock);
-#else
-	spin_lock(&uart->port.lock);
-	while ((UART_GET_IIR(uart) & IIR_STATUS) == IIR_RX_READY)
-		bfin_serial_rx_chars(uart);
-	spin_unlock(&uart->port.lock);
-#endif
+
 	return IRQ_HANDLED;
 }
 
@@ -374,21 +350,11 @@ static irqreturn_t bfin_serial_tx_int(int irq, void *dev_id)
 {
 	struct bfin_serial_port *uart = dev_id;
 
-#ifdef CONFIG_BF54x
-	unsigned short status;
 	spin_lock(&uart->port.lock);
-	status = UART_GET_LSR(uart);
-	while ((UART_GET_IER(uart) & ETBEI) && (status & THRE)) {
+	if ((UART_GET_IER(uart) & ETBEI) && (UART_GET_LSR(uart) & THRE))
 		bfin_serial_tx_chars(uart);
-		status = UART_GET_LSR(uart);
-	}
 	spin_unlock(&uart->port.lock);
-#else
-	spin_lock(&uart->port.lock);
-	while ((UART_GET_IIR(uart) & IIR_STATUS) == IIR_TX_READY)
-		bfin_serial_tx_chars(uart);
-	spin_unlock(&uart->port.lock);
-#endif
+
 	return IRQ_HANDLED;
 }
 
-- 
1.5.3.4

  parent reply	other threads:[~2008-01-30  9:31 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-01-30  9:30 [PATCH 00/12] Blackfin serial driver updates Bryan Wu
2008-01-30  9:30 ` [PATCH 01/12] [8250 Serial Driver]: Added support for 8250-class UARTs in HV Sistemas H8606 board Bryan Wu
2008-01-30  9:30 ` Bryan Wu [this message]
2008-01-30  9:30 ` [PATCH 03/12] [Blackfin] serial driver: Clean up UART DMA code Bryan Wu
2008-01-30  9:30 ` [PATCH 04/12] [Blackfin] serial driver: Fix bug Free rx dma buffer in shutdown Bryan Wu
2008-01-30  9:30 ` [PATCH 05/12] [Blackfin] serial driver: Fix bug serial driver in DMA mode spams history to console on shell restart Bryan Wu
2008-01-30  9:30 ` [PATCH 06/12] [Blackfin] serial driver: fix bug - should not wait for the TFI bit, just clear it when tx stop Bryan Wu
2008-01-30  9:30 ` [PATCH 07/12] [Blackfin] serial driver: add extra IRQ flag for 8250 serial driver Bryan Wu
2008-01-30  9:30 ` [PATCH 08/12] [Blackfin] serial driver: fix bug - cache the bits of the LSR on systems where the LSR is read-to-clear Bryan Wu
2008-01-30  9:30 ` [PATCH 09/12] [Blackfin] serial driver: rework break flood anomaly handling to be more robust/realistic about what we can actually work around Bryan Wu
2008-01-30  9:30 ` [PATCH 10/12] [Blackfin] serial driver: use simpler comment headers and strip out information that is maintained in the scm's log Bryan Wu
2008-01-30  9:30 ` [PATCH 11/12] [Blackfin] serial driver: ADSP-BF52x arch/mach support Bryan Wu
2008-01-30 21:01   ` Mike Frysinger
2008-01-31  6:47     ` [PATCH 11/12 try #2] " Bryan Wu
2008-01-30  9:30 ` [PATCH 12/12] [Blackfin] serial driver: Fix bug Poll RTS/CTS status in DMA mode as well Bryan Wu

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