Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759466AbYA3Jbh (ORCPT ); Wed, 30 Jan 2008 04:31:37 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756375AbYA3JaV (ORCPT ); Wed, 30 Jan 2008 04:30:21 -0500 Received: from nwd2mail10.analog.com ([137.71.25.55]:40869 "EHLO nwd2mail10.analog.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754444AbYA3JaQ (ORCPT ); Wed, 30 Jan 2008 04:30:16 -0500 X-IronPort-AV: E=Sophos;i="4.25,276,1199682000"; d="scan'208";a="61204641" From: Bryan Wu To: linux-serial@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Sonic Zhang , Bryan Wu 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 Message-Id: <1201685412-29095-3-git-send-email-bryan.wu@analog.com> X-Mailer: git-send-email 1.5.3.4 In-Reply-To: <1201685412-29095-1-git-send-email-bryan.wu@analog.com> References: <1201685412-29095-1-git-send-email-bryan.wu@analog.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4467 Lines: 148 From: Sonic Zhang 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 Signed-off-by: Bryan Wu --- 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 -- 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/