From mboxrd@z Thu Jan 1 00:00:00 1970 From: boris.brezillon@free-electrons.com (Boris Brezillon) Date: Fri, 27 Feb 2015 16:09:58 +0100 Subject: [PATCH 6/6] tty: serial: atmel: rework interrupt and wakeup handling In-Reply-To: <1425049798-5891-1-git-send-email-boris.brezillon@free-electrons.com> References: <1425049798-5891-1-git-send-email-boris.brezillon@free-electrons.com> Message-ID: <1425049798-5891-7-git-send-email-boris.brezillon@free-electrons.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org The IRQ line connected to the DBGU UART is often shared with a timer device which request the IRQ with IRQF_NO_SUSPEND. Since the UART driver is correctly disabling IRQs when entering suspend we can safely request the IRQ with IRQF_COND_SUSPEND so that irq core will not complain about mixing IRQF_NO_SUSPEND and !IRQF_NO_SUSPEND. Rework the interrupt handler to wake the system up when an interrupt happens on the DEBUG_UART while the system is suspended. Signed-off-by: Boris Brezillon --- drivers/tty/serial/atmel_serial.c | 49 +++++++++++++++++++++++++++++++++++---- 1 file changed, 45 insertions(+), 4 deletions(-) diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c index 846552b..4e959c4 100644 --- a/drivers/tty/serial/atmel_serial.c +++ b/drivers/tty/serial/atmel_serial.c @@ -47,6 +47,7 @@ #include #include #include +#include #include #include @@ -173,6 +174,12 @@ struct atmel_uart_port { bool ms_irq_enabled; bool is_usart; /* usart or uart */ struct timer_list uart_timer; /* uart timer */ + + bool suspended; + unsigned int pending; + unsigned int pending_status; + spinlock_t lock_suspended; + int (*prepare_rx)(struct uart_port *port); int (*prepare_tx)(struct uart_port *port); void (*schedule_rx)(struct uart_port *port); @@ -1179,12 +1186,15 @@ static irqreturn_t atmel_interrupt(int irq, void *dev_id) { struct uart_port *port = dev_id; struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); - unsigned int status, pending, pass_counter = 0; + unsigned int status, pending, mask, pass_counter = 0; bool gpio_handled = false; + spin_lock(&atmel_port->lock_suspended); + do { status = atmel_get_lines_status(port); - pending = status & UART_GET_IMR(port); + mask = UART_GET_IMR(port); + pending = status & mask; if (!gpio_handled) { /* * Dealing with GPIO interrupt @@ -1206,11 +1216,21 @@ static irqreturn_t atmel_interrupt(int irq, void *dev_id) if (!pending) break; + if (atmel_port->suspended) { + atmel_port->pending |= pending; + atmel_port->pending_status = status; + UART_PUT_IDR(port, mask); + pm_system_wakeup(); + break; + } + atmel_handle_receive(port, pending); atmel_handle_status(port, pending, status); atmel_handle_transmit(port, pending); } while (pass_counter++ < ATMEL_ISR_PASS_LIMIT); + spin_unlock(&atmel_port->lock_suspended); + return pass_counter ? IRQ_HANDLED : IRQ_NONE; } @@ -1742,7 +1762,8 @@ static int atmel_startup(struct uart_port *port) /* * Allocate the IRQ */ - retval = request_irq(port->irq, atmel_interrupt, IRQF_SHARED, + retval = request_irq(port->irq, atmel_interrupt, + IRQF_SHARED | IRQF_COND_SUSPEND, tty ? tty->name : "atmel_serial", port); if (retval) { dev_err(port->dev, "atmel_startup - Can't get irq\n"); @@ -2513,8 +2534,14 @@ static int atmel_serial_suspend(struct platform_device *pdev, /* we can not wake up if we're running on slow clock */ atmel_port->may_wakeup = device_may_wakeup(&pdev->dev); - if (atmel_serial_clk_will_stop()) + if (atmel_serial_clk_will_stop()) { + unsigned long flags; + + spin_lock_irqsave(&atmel_port->lock_suspended, flags); + atmel_port->suspended = true; + spin_unlock_irqrestore(&atmel_port->lock_suspended, flags); device_set_wakeup_enable(&pdev->dev, 0); + } uart_suspend_port(&atmel_uart, port); @@ -2525,6 +2552,18 @@ static int atmel_serial_resume(struct platform_device *pdev) { struct uart_port *port = platform_get_drvdata(pdev); struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); + unsigned long flags; + + spin_lock_irqsave(&atmel_port->lock_suspended, flags); + if (atmel_port->pending) { + atmel_handle_receive(port, atmel_port->pending); + atmel_handle_status(port, atmel_port->pending, + atmel_port->pending_status); + atmel_handle_transmit(port, atmel_port->pending); + atmel_port->pending = 0; + } + atmel_port->suspended = false; + spin_unlock_irqrestore(&atmel_port->lock_suspended, flags); uart_resume_port(&atmel_uart, port); device_set_wakeup_enable(&pdev->dev, atmel_port->may_wakeup); @@ -2593,6 +2632,8 @@ static int atmel_serial_probe(struct platform_device *pdev) port->backup_imr = 0; port->uart.line = ret; + spin_lock_init(&port->lock_suspended); + ret = atmel_init_gpios(port, &pdev->dev); if (ret < 0) dev_err(&pdev->dev, "%s", -- 1.9.1