X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=drivers%2Fmmc%2Fcard%2Fsdio_uart.c;h=78ad48718ab028e61b1d77d83e29de8efbe9930c;hb=1ff8419871ea757ae0298aa296bcff9b2ca48561;hp=190120d1449a5eddc9a7c6c2badaa44aad7f237d;hpb=5ed334a1f8caaae98806d572f78c5802975ea20f;p=linux-2.6

diff --git a/drivers/mmc/card/sdio_uart.c b/drivers/mmc/card/sdio_uart.c
index 190120d144..78ad48718a 100644
--- a/drivers/mmc/card/sdio_uart.c
+++ b/drivers/mmc/card/sdio_uart.c
@@ -79,6 +79,7 @@ struct sdio_uart_port {
 	struct mutex		open_lock;
 	struct sdio_func	*func;
 	struct mutex		func_lock;
+	struct task_struct	*in_sdio_uart_irq;
 	unsigned int		regs_offset;
 	struct circ_buf		xmit;
 	spinlock_t		write_lock;
@@ -186,14 +187,16 @@ static int sdio_uart_claim_func(struct sdio_uart_port *port)
 		mutex_unlock(&port->func_lock);
 		return -ENODEV;
 	}
-	sdio_claim_host(port->func);
+	if (likely(port->in_sdio_uart_irq != current))
+		sdio_claim_host(port->func);
 	mutex_unlock(&port->func_lock);
 	return 0;
 }
 
 static inline void sdio_uart_release_func(struct sdio_uart_port *port)
 {
-	sdio_release_host(port->func);
+	if (likely(port->in_sdio_uart_irq != current))
+		sdio_release_host(port->func);
 }
 
 static inline unsigned int sdio_in(struct sdio_uart_port *port, int offset)
@@ -383,7 +386,7 @@ static void sdio_uart_stop_rx(struct sdio_uart_port *port)
 	sdio_out(port, UART_IER, port->ier);
 }
 
-static void sdio_uart_receive_chars(struct sdio_uart_port *port, int *status)
+static void sdio_uart_receive_chars(struct sdio_uart_port *port, unsigned int *status)
 {
 	struct tty_struct *tty = port->tty;
 	unsigned int ch, flag;
@@ -511,15 +514,29 @@ static void sdio_uart_irq(struct sdio_func *func)
 	struct sdio_uart_port *port = sdio_get_drvdata(func);
 	unsigned int iir, lsr;
 
+	/*
+	 * In a few places sdio_uart_irq() is called directly instead of
+	 * waiting for the actual interrupt to be raised and the SDIO IRQ
+	 * thread scheduled in order to reduce latency.  However, some
+	 * interaction with the tty core may end up calling us back
+	 * (serial echo, flow control, etc.) through those same places
+	 * causing undesirable effects.  Let's stop the recursion here.
+	 */
+	if (unlikely(port->in_sdio_uart_irq == current))
+		return;
+
 	iir = sdio_in(port, UART_IIR);
 	if (iir & UART_IIR_NO_INT)
 		return;
+
+	port->in_sdio_uart_irq = current;
 	lsr = sdio_in(port, UART_LSR);
 	if (lsr & UART_LSR_DR)
 		sdio_uart_receive_chars(port, &lsr);
 	sdio_uart_check_modem_status(port);
 	if (lsr & UART_LSR_THRE)
 		sdio_uart_transmit_chars(port);
+	port->in_sdio_uart_irq = NULL;
 }
 
 static int sdio_uart_startup(struct sdio_uart_port *port)
@@ -868,12 +885,14 @@ static void sdio_uart_set_termios(struct tty_struct *tty, struct ktermios *old_t
 	sdio_uart_release_func(port);
 }
 
-static void sdio_uart_break_ctl(struct tty_struct *tty, int break_state)
+static int sdio_uart_break_ctl(struct tty_struct *tty, int break_state)
 {
 	struct sdio_uart_port *port = tty->driver_data;
+	int result;
 
-	if (sdio_uart_claim_func(port) != 0)
-		return;
+	result = sdio_uart_claim_func(port);
+	if (result != 0)
+		return result;
 
 	if (break_state == -1)
 		port->lcr |= UART_LCR_SBC;
@@ -882,6 +901,7 @@ static void sdio_uart_break_ctl(struct tty_struct *tty, int break_state)
 	sdio_out(port, UART_LCR, port->lcr);
 
 	sdio_uart_release_func(port);
+	return 0;
 }
 
 static int sdio_uart_tiocmget(struct tty_struct *tty, struct file *file)
@@ -1106,6 +1126,8 @@ static int __init sdio_uart_init(void)
 	tty_drv->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV;
 	tty_drv->init_termios = tty_std_termios;
 	tty_drv->init_termios.c_cflag = B4800 | CS8 | CREAD | HUPCL | CLOCAL;
+	tty_drv->init_termios.c_ispeed = 4800;
+	tty_drv->init_termios.c_ospeed = 4800;
 	tty_set_operations(tty_drv, &sdio_uart_ops);
 
 	ret = tty_register_driver(tty_drv);