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Subject[PATCH 09/10] tty: xuartps: Implement suspend/resume callbacks
Date
Implement suspend and resume callbacks in order to support system
suspend/hibernation.

Signed-off-by: Soren Brinkmann <soren.brinkmann@xilinx.com>
---
drivers/tty/serial/xilinx_uartps.c | 114 +++++++++++++++++++++++++++++++++++++
1 file changed, 114 insertions(+)

diff --git a/drivers/tty/serial/xilinx_uartps.c b/drivers/tty/serial/xilinx_uartps.c
index 82195040e906..9ecd8ea4f3ae 100644
--- a/drivers/tty/serial/xilinx_uartps.c
+++ b/drivers/tty/serial/xilinx_uartps.c
@@ -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,
},
};

--
1.8.4.1


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