Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 4b47d9aa authored by Soren Brinkmann's avatar Soren Brinkmann Committed by Greg Kroah-Hartman
Browse files

tty: xuartps: Implement suspend/resume callbacks 



Implement suspend and resume callbacks in order to support system
suspend/hibernation.

Signed-off-by: default avatarSoren Brinkmann <soren.brinkmann@xilinx.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent c4b0510c

drivers/tty/serial/xilinx_uartps.c

+114 −0
Original line number Diff line number Diff line
@@ -1198,6 +1198,119 @@ console_initcall(xuartps_console_init); 


#endif /* CONFIG_SERIAL_XILINX_PS_UART_CONSOLE */



#ifdef CONFIG_PM_SLEEP

/**

 * xuartps_suspend - suspend event

 * @device: Pointer to the device structure

 *

 * Returns 0

 */

static int xuartps_suspend(struct device *device)

{

	struct uart_port *port = dev_get_drvdata(device);

	struct tty_struct *tty;

	struct device *tty_dev;

	int may_wake = 0;



	/* Get the tty which could be NULL so don't assume it's valid */

	tty = tty_port_tty_get(&port->state->port);

	if (tty) {

		tty_dev = tty->dev;

		may_wake = device_may_wakeup(tty_dev);

		tty_kref_put(tty);

	}



	/*

	 * Call the API provided in serial_core.c file which handles

	 * the suspend.

	 */

	uart_suspend_port(&xuartps_uart_driver, port);

	if (console_suspend_enabled && !may_wake) {

		struct xuartps *xuartps = port->private_data;



		clk_disable(xuartps->refclk);

		clk_disable(xuartps->aperclk);

	} else {

		unsigned long flags = 0;



		spin_lock_irqsave(&port->lock, flags);

		/* Empty the receive FIFO 1st before making changes */

		while (!(xuartps_readl(XUARTPS_SR_OFFSET) & XUARTPS_SR_RXEMPTY))

			xuartps_readl(XUARTPS_FIFO_OFFSET);

		/* set RX trigger level to 1 */

		xuartps_writel(1, XUARTPS_RXWM_OFFSET);

		/* disable RX timeout interrups */

		xuartps_writel(XUARTPS_IXR_TOUT, XUARTPS_IDR_OFFSET);

		spin_unlock_irqrestore(&port->lock, flags);

	}



	return 0;

}



/**

 * xuartps_resume - Resume after a previous suspend

 * @device: Pointer to the device structure

 *

 * Returns 0

 */

static int xuartps_resume(struct device *device)

{

	struct uart_port *port = dev_get_drvdata(device);

	unsigned long flags = 0;

	u32 ctrl_reg;

	struct tty_struct *tty;

	struct device *tty_dev;

	int may_wake = 0;



	/* Get the tty which could be NULL so don't assume it's valid */

	tty = tty_port_tty_get(&port->state->port);

	if (tty) {

		tty_dev = tty->dev;

		may_wake = device_may_wakeup(tty_dev);

		tty_kref_put(tty);

	}



	if (console_suspend_enabled && !may_wake) {

		struct xuartps *xuartps = port->private_data;



		clk_enable(xuartps->aperclk);

		clk_enable(xuartps->refclk);



		spin_lock_irqsave(&port->lock, flags);



		/* Set TX/RX Reset */

		xuartps_writel(xuartps_readl(XUARTPS_CR_OFFSET) |

				(XUARTPS_CR_TXRST | XUARTPS_CR_RXRST),

				XUARTPS_CR_OFFSET);

		while (xuartps_readl(XUARTPS_CR_OFFSET) &

				(XUARTPS_CR_TXRST | XUARTPS_CR_RXRST))

			cpu_relax();



		/* restore rx timeout value */

		xuartps_writel(rx_timeout, XUARTPS_RXTOUT_OFFSET);

		/* Enable Tx/Rx */

		ctrl_reg = xuartps_readl(XUARTPS_CR_OFFSET);

		xuartps_writel(

			(ctrl_reg & ~(XUARTPS_CR_TX_DIS | XUARTPS_CR_RX_DIS)) |

			(XUARTPS_CR_TX_EN | XUARTPS_CR_RX_EN),

			XUARTPS_CR_OFFSET);



		spin_unlock_irqrestore(&port->lock, flags);

	} else {

		spin_lock_irqsave(&port->lock, flags);

		/* restore original rx trigger level */

		xuartps_writel(rx_trigger_level, XUARTPS_RXWM_OFFSET);

		/* enable RX timeout interrupt */

		xuartps_writel(XUARTPS_IXR_TOUT, XUARTPS_IER_OFFSET);

		spin_unlock_irqrestore(&port->lock, flags);

	}



	return uart_resume_port(&xuartps_uart_driver, port);

}

#endif /* ! CONFIG_PM_SLEEP */



static SIMPLE_DEV_PM_OPS(xuartps_dev_pm_ops, xuartps_suspend, xuartps_resume);



/** Structure Definitions

 */

static struct uart_driver xuartps_uart_driver = {
@@ -1348,6 +1461,7 @@ static struct platform_driver xuartps_platform_driver = { 
		.owner = THIS_MODULE,

		.name = XUARTPS_NAME,		/* Driver name */

		.of_match_table = xuartps_of_match,

		.pm = &xuartps_dev_pm_ops,

		},

};