serial: combined uart: add pm ops

Add support for suspend/resume. This is necessary to ensure that RX interrupts
are received after resuming from suspend.

Bug 1527617
Bug 1817040

Change-Id: Ic54af7a916fb99fc0017524a11cad9acf0424008
Signed-off-by: Mustafa Yigit Bilgen <mbilgen@nvidia.com>
Reviewed-on: http://git-master/r/1503302
Reviewed-by: Liang Cheng (SW) <licheng@nvidia.com>
Reviewed-by: Akhilesh Khumbum <akhumbum@nvidia.com>
Reviewed-by: Robert Collins <rcollins@nvidia.com>
GVS: Gerrit_Virtual_Submit

1 files changed, 47 insertions, 10 deletions

diff --git a/drivers/tty/serial/tegra-combined-uart.c b/drivers/tty/serial/tegra-combined-uart.c
index 76435e150..3f19319ed 100644
--- a/drivers/tty/serial/tegra-combined-uart.c
+++ b/drivers/tty/serial/tegra-combined-uart.c
@@ -59,16 +59,45 @@ static int uart_null_func(struct uart_port *port)
         return 0;
 }
 
-static int uart_shutdown(struct uart_port *port)
+static void tegra_combined_uart_disable_sm_irq(void)
 {
         u32 reg_val;
         /*
-         * disable interrupt
          * WARNING: HSP_INT_IE_0 is not protected for RMW.
          */
         reg_val = readl(top0_cmn_base + HSP_INT_IE_0);
         reg_val &= ~(1 << MBOX0_FULL_BIT);
         writel(reg_val, top0_cmn_base + HSP_INT_IE_0);
+}
+
+static void tegra_combined_uart_enable_sm_irq(void)
+{
+        u32 reg_val;
+        /*
+         * WARNING: HSP_INT_IE_0 is not protected for RMW.
+         */
+        reg_val = readl(top0_cmn_base + HSP_INT_IE_0);
+        reg_val |= (1 << MBOX0_FULL_BIT);
+        writel(reg_val, top0_cmn_base + HSP_INT_IE_0);
+}
+
+static int tegra_combined_uart_suspend(struct device *dev)
+{
+        tegra_combined_uart_disable_sm_irq();
+
+        return 0;
+}
+
+static int tegra_combined_uart_resume(struct device *dev)
+{
+        tegra_combined_uart_enable_sm_irq();
+
+        return 0;
+}
+
+static int uart_shutdown(struct uart_port *port)
+{
+        tegra_combined_uart_disable_sm_irq();
         /* free IRQ */
         free_irq(tegra_combined_uart_port.irq, port);
 
@@ -222,13 +251,13 @@ static irqreturn_t tegra_combined_uart_rx(int irq, void *dev_id)
 
         tegra_combined_uart_handle_rx_msg(reg_val);
         spin_unlock_irqrestore(&mbox_lock, flags);
+
         return IRQ_HANDLED;
 }
 
 static int tegra_combined_uart_startup(struct uart_port *port)
 {
         int ret;
-        u32 reg_val;
         /* allocate IRQ */
         ret = request_irq(tegra_combined_uart_port.irq, tegra_combined_uart_rx,
                 0, "combined_uart rx", port);
@@ -236,13 +265,9 @@ static int tegra_combined_uart_startup(struct uart_port *port)
                 pr_err("%s: request_irq error\n", __func__);
                 return ret;
         }
-        /*
-         * enable interrupt
-         * WARNING: HSP_INT_IE_0 is not protected for RMW.
-         */
-        reg_val = readl(top0_cmn_base + HSP_INT_IE_0);
-        reg_val |= (1 << MBOX0_FULL_BIT);
-        writel(reg_val, top0_cmn_base + HSP_INT_IE_0);
+
+        tegra_combined_uart_enable_sm_irq();
+
         return ret;
 }
 
@@ -306,6 +331,7 @@ err_mapping:
                 iounmap(top0_mbox01_base);
         if (top0_cmn_base != NULL && !IS_ERR(top0_cmn_base))
                 iounmap(top0_cmn_base);
+
         return ret;
 }
 
@@ -317,6 +343,7 @@ static int tegra_combined_uart_remove(struct platform_device *pdev)
         iounmap(spe_mbox_reg);
         iounmap(top0_mbox01_base);
         iounmap(top0_cmn_base);
+
         return 0;
 }
 
@@ -398,12 +425,22 @@ static struct uart_driver tegra_combined_uart_driver = {
         .nr             = 1,
 };
 
+#ifdef CONFIG_PM
+static const struct dev_pm_ops tegra_combined_uart_pm_ops = {
+        .suspend = tegra_combined_uart_suspend,
+        .resume = tegra_combined_uart_resume,
+};
+#endif
+
 static struct platform_driver tegra_combined_uart_platform_driver = {
         .probe          = tegra_combined_uart_probe,
         .remove         = tegra_combined_uart_remove,
         .driver         = {
                 .name   = "tegra-combined-uart",
                 .of_match_table = of_match_ptr(tegra_combined_uart_of_match),
+#ifdef CONFIG_PM
+                .pm = &tegra_combined_uart_pm_ops,
+#endif
         },
 };