ARM: OMAP2+: UART: Add runtime pm support for omap-serial driver

Adapts omap-serial driver to use pm_runtime API's.
Use runtime runtime API's to handle uart clocks and obtain
device_usage statics. Set runtime API's usage to irq_safe so that
we can use get_sync from irq context. Auto-suspend for port specific
activities and put for reg access. Moving suspend/resume hooks
to dev_pm_ops structure and bind with config_suspend to avoid any
compilation warning if config_suspend is disabled.

By default uart autosuspend delay is set to -1 to avoid character loss
if uart's are autoidled and woken up on rx pin.

After boot up UART's can be autoidled by setting autosuspend delay from sysfs.

echo 3000 > /sys/devices/platform/omap/omap_uart.X/power/autosuspend_delay_ms
X=0,1,2,3 for UART1/2/3/4. Number of uarts available may vary across omap_soc.

Also if uart is not wakeup capable we can prevent runtime autosuspend by
forbiding runtime.

Signed-off-by: Govindraj.R <govindraj.raja@ti.com>
Acked-by: Alan Cox <alan@linux.intel.com>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Kevin Hilman <khilman@ti.com>

1 files changed, 109 insertions, 13 deletions

diff --git a/drivers/tty/serial/omap-serial.c b/drivers/tty/serial/omap-serial.c
index 31f0cbf73c18..f16ef4b9363d 100644
--- a/drivers/tty/serial/omap-serial.c
+++ b/drivers/tty/serial/omap-serial.c
@@ -37,11 +37,14 @@
 #include <linux/clk.h>
 #include <linux/serial_core.h>
 #include <linux/irq.h>
+#include <linux/pm_runtime.h>
 
 #include <plat/dma.h>
 #include <plat/dmtimer.h>
 #include <plat/omap-serial.h>
 
+#define OMAP_UART_AUTOSUSPEND_DELAY -1
+
 static struct uart_omap_port *ui[OMAP_MAX_HSUART_PORTS];
 
 /* Forward declaration of functions */
@@ -102,6 +105,8 @@ static void serial_omap_stop_rxdma(struct uart_omap_port *up)
                 omap_free_dma(up->uart_dma.rx_dma_channel);
                 up->uart_dma.rx_dma_channel = OMAP_UART_DMA_CH_FREE;
                 up->uart_dma.rx_dma_used = false;
+                pm_runtime_mark_last_busy(&up->pdev->dev);
+                pm_runtime_put_autosuspend(&up->pdev->dev);
         }
 }
 
@@ -110,8 +115,11 @@ static void serial_omap_enable_ms(struct uart_port *port)
         struct uart_omap_port *up = (struct uart_omap_port *)port;
 
         dev_dbg(up->port.dev, "serial_omap_enable_ms+%d\n", up->pdev->id);
+
+        pm_runtime_get_sync(&up->pdev->dev);
         up->ier |= UART_IER_MSI;
         serial_out(up, UART_IER, up->ier);
+        pm_runtime_put(&up->pdev->dev);
 }
 
 static void serial_omap_stop_tx(struct uart_port *port)
@@ -129,23 +137,32 @@ static void serial_omap_stop_tx(struct uart_port *port)
                 omap_stop_dma(up->uart_dma.tx_dma_channel);
                 omap_free_dma(up->uart_dma.tx_dma_channel);
                 up->uart_dma.tx_dma_channel = OMAP_UART_DMA_CH_FREE;
+                pm_runtime_mark_last_busy(&up->pdev->dev);
+                pm_runtime_put_autosuspend(&up->pdev->dev);
         }
 
+        pm_runtime_get_sync(&up->pdev->dev);
         if (up->ier & UART_IER_THRI) {
                 up->ier &= ~UART_IER_THRI;
                 serial_out(up, UART_IER, up->ier);
         }
+
+        pm_runtime_mark_last_busy(&up->pdev->dev);
+        pm_runtime_put_autosuspend(&up->pdev->dev);
 }
 
 static void serial_omap_stop_rx(struct uart_port *port)
 {
         struct uart_omap_port *up = (struct uart_omap_port *)port;
 
+        pm_runtime_get_sync(&up->pdev->dev);
         if (up->use_dma)
                 serial_omap_stop_rxdma(up);
         up->ier &= ~UART_IER_RLSI;
         up->port.read_status_mask &= ~UART_LSR_DR;
         serial_out(up, UART_IER, up->ier);
+        pm_runtime_mark_last_busy(&up->pdev->dev);
+        pm_runtime_put_autosuspend(&up->pdev->dev);
 }
 
 static inline void receive_chars(struct uart_omap_port *up, int *status)
@@ -262,7 +279,10 @@ static void serial_omap_start_tx(struct uart_port *port)
         int ret = 0;
 
         if (!up->use_dma) {
+                pm_runtime_get_sync(&up->pdev->dev);
                 serial_omap_enable_ier_thri(up);
+                pm_runtime_mark_last_busy(&up->pdev->dev);
+                pm_runtime_put_autosuspend(&up->pdev->dev);
                 return;
         }
 
@@ -272,6 +292,7 @@ static void serial_omap_start_tx(struct uart_port *port)
         xmit = &up->port.state->xmit;
 
         if (up->uart_dma.tx_dma_channel == OMAP_UART_DMA_CH_FREE) {
+                pm_runtime_get_sync(&up->pdev->dev);
                 ret = omap_request_dma(up->uart_dma.uart_dma_tx,
                                 "UART Tx DMA",
                                 (void *)uart_tx_dma_callback, up,
@@ -354,9 +375,13 @@ static inline irqreturn_t serial_omap_irq(int irq, void *dev_id)
         unsigned int iir, lsr;
         unsigned long flags;
 
+        pm_runtime_get_sync(&up->pdev->dev);
         iir = serial_in(up, UART_IIR);
-        if (iir & UART_IIR_NO_INT)
+        if (iir & UART_IIR_NO_INT) {
+                pm_runtime_mark_last_busy(&up->pdev->dev);
+                pm_runtime_put_autosuspend(&up->pdev->dev);
                 return IRQ_NONE;
+        }
 
         spin_lock_irqsave(&up->port.lock, flags);
         lsr = serial_in(up, UART_LSR);
@@ -378,6 +403,9 @@ static inline irqreturn_t serial_omap_irq(int irq, void *dev_id)
                 transmit_chars(up);
 
         spin_unlock_irqrestore(&up->port.lock, flags);
+        pm_runtime_mark_last_busy(&up->pdev->dev);
+        pm_runtime_put_autosuspend(&up->pdev->dev);
+
         up->port_activity = jiffies;
         return IRQ_HANDLED;
 }
@@ -388,11 +416,12 @@ static unsigned int serial_omap_tx_empty(struct uart_port *port)
         unsigned long flags = 0;
         unsigned int ret = 0;
 
+        pm_runtime_get_sync(&up->pdev->dev);
         dev_dbg(up->port.dev, "serial_omap_tx_empty+%d\n", up->pdev->id);
         spin_lock_irqsave(&up->port.lock, flags);
         ret = serial_in(up, UART_LSR) & UART_LSR_TEMT ? TIOCSER_TEMT : 0;
         spin_unlock_irqrestore(&up->port.lock, flags);
-
+        pm_runtime_put(&up->pdev->dev);
         return ret;
 }
 
@@ -402,7 +431,10 @@ static unsigned int serial_omap_get_mctrl(struct uart_port *port)
         unsigned char status;
         unsigned int ret = 0;
 
+        pm_runtime_get_sync(&up->pdev->dev);
         status = check_modem_status(up);
+        pm_runtime_put(&up->pdev->dev);
+
         dev_dbg(up->port.dev, "serial_omap_get_mctrl+%d\n", up->pdev->id);
 
         if (status & UART_MSR_DCD)
@@ -433,8 +465,10 @@ static void serial_omap_set_mctrl(struct uart_port *port, unsigned int mctrl)
         if (mctrl & TIOCM_LOOP)
                 mcr |= UART_MCR_LOOP;
 
+        pm_runtime_get_sync(&up->pdev->dev);
         mcr |= up->mcr;
         serial_out(up, UART_MCR, mcr);
+        pm_runtime_put(&up->pdev->dev);
 }
 
 static void serial_omap_break_ctl(struct uart_port *port, int break_state)
@@ -443,6 +477,7 @@ static void serial_omap_break_ctl(struct uart_port *port, int break_state)
         unsigned long flags = 0;
 
         dev_dbg(up->port.dev, "serial_omap_break_ctl+%d\n", up->pdev->id);
+        pm_runtime_get_sync(&up->pdev->dev);
         spin_lock_irqsave(&up->port.lock, flags);
         if (break_state == -1)
                 up->lcr |= UART_LCR_SBC;
@@ -450,6 +485,7 @@ static void serial_omap_break_ctl(struct uart_port *port, int break_state)
                 up->lcr &= ~UART_LCR_SBC;
         serial_out(up, UART_LCR, up->lcr);
         spin_unlock_irqrestore(&up->port.lock, flags);
+        pm_runtime_put(&up->pdev->dev);
 }
 
 static int serial_omap_startup(struct uart_port *port)
@@ -468,6 +504,7 @@ static int serial_omap_startup(struct uart_port *port)
 
         dev_dbg(up->port.dev, "serial_omap_startup+%d\n", up->pdev->id);
 
+        pm_runtime_get_sync(&up->pdev->dev);
         /*
          * Clear the FIFO buffers and disable them.
          * (they will be reenabled in set_termios())
@@ -523,6 +560,8 @@ static int serial_omap_startup(struct uart_port *port)
         /* Enable module level wake up */
         serial_out(up, UART_OMAP_WER, OMAP_UART_WER_MOD_WKUP);
 
+        pm_runtime_mark_last_busy(&up->pdev->dev);
+        pm_runtime_put_autosuspend(&up->pdev->dev);
         up->port_activity = jiffies;
         return 0;
 }
@@ -533,6 +572,8 @@ static void serial_omap_shutdown(struct uart_port *port)
         unsigned long flags = 0;
 
         dev_dbg(up->port.dev, "serial_omap_shutdown+%d\n", up->pdev->id);
+
+        pm_runtime_get_sync(&up->pdev->dev);
         /*
          * Disable interrupts from this port
          */
@@ -566,6 +607,8 @@ static void serial_omap_shutdown(struct uart_port *port)
                         up->uart_dma.rx_buf_dma_phys);
                 up->uart_dma.rx_buf = NULL;
         }
+
+        pm_runtime_put(&up->pdev->dev);
         free_irq(up->port.irq, up);
 }
 
@@ -680,6 +723,7 @@ serial_omap_set_termios(struct uart_port *port, struct ktermios *termios,
          * Ok, we're now changing the port state. Do it with
          * interrupts disabled.
          */
+        pm_runtime_get_sync(&up->pdev->dev);
         spin_lock_irqsave(&up->port.lock, flags);
 
         /*
@@ -809,6 +853,7 @@ serial_omap_set_termios(struct uart_port *port, struct ktermios *termios,
         serial_omap_configure_xonxoff(up, termios);
 
         spin_unlock_irqrestore(&up->port.lock, flags);
+        pm_runtime_put(&up->pdev->dev);
         dev_dbg(up->port.dev, "serial_omap_set_termios+%d\n", up->pdev->id);
 }
 
@@ -820,6 +865,8 @@ serial_omap_pm(struct uart_port *port, unsigned int state,
         unsigned char efr;
 
         dev_dbg(up->port.dev, "serial_omap_pm+%d\n", up->pdev->id);
+
+        pm_runtime_get_sync(&up->pdev->dev);
         serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
         efr = serial_in(up, UART_EFR);
         serial_out(up, UART_EFR, efr | UART_EFR_ECB);
@@ -829,6 +876,15 @@ serial_omap_pm(struct uart_port *port, unsigned int state,
         serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
         serial_out(up, UART_EFR, efr);
         serial_out(up, UART_LCR, 0);
+
+        if (!device_may_wakeup(&up->pdev->dev)) {
+                if (!state)
+                        pm_runtime_forbid(&up->pdev->dev);
+                else
+                        pm_runtime_allow(&up->pdev->dev);
+        }
+
+        pm_runtime_put(&up->pdev->dev);
 }
 
 static void serial_omap_release_port(struct uart_port *port)
@@ -906,19 +962,26 @@ static inline void wait_for_xmitr(struct uart_omap_port *up)
 static void serial_omap_poll_put_char(struct uart_port *port, unsigned char ch)
 {
         struct uart_omap_port *up = (struct uart_omap_port *)port;
+
+        pm_runtime_get_sync(&up->pdev->dev);
         wait_for_xmitr(up);
         serial_out(up, UART_TX, ch);
+        pm_runtime_put(&up->pdev->dev);
 }
 
 static int serial_omap_poll_get_char(struct uart_port *port)
 {
         struct uart_omap_port *up = (struct uart_omap_port *)port;
-        unsigned int status = serial_in(up, UART_LSR);
+        unsigned int status;
 
+        pm_runtime_get_sync(&up->pdev->dev);
+        status = serial_in(up, UART_LSR);
         if (!(status & UART_LSR_DR))
                 return NO_POLL_CHAR;
 
-        return serial_in(up, UART_RX);
+        status = serial_in(up, UART_RX);
+        pm_runtime_put(&up->pdev->dev);
+        return status;
 }
 
 #endif /* CONFIG_CONSOLE_POLL */
@@ -946,6 +1009,8 @@ serial_omap_console_write(struct console *co, const char *s,
         unsigned int ier;
         int locked = 1;
 
+        pm_runtime_get_sync(&up->pdev->dev);
+
         local_irq_save(flags);
         if (up->port.sysrq)
                 locked = 0;
@@ -978,6 +1043,8 @@ serial_omap_console_write(struct console *co, const char *s,
         if (up->msr_saved_flags)
                 check_modem_status(up);
 
+        pm_runtime_mark_last_busy(&up->pdev->dev);
+        pm_runtime_put_autosuspend(&up->pdev->dev);
         if (locked)
                 spin_unlock(&up->port.lock);
         local_irq_restore(flags);
@@ -1060,24 +1127,25 @@ static struct uart_driver serial_omap_reg = {
         .cons           = OMAP_CONSOLE,
 };
 
-static int
-serial_omap_suspend(struct platform_device *pdev, pm_message_t state)
+#ifdef CONFIG_SUSPEND
+static int serial_omap_suspend(struct device *dev)
 {
-        struct uart_omap_port *up = platform_get_drvdata(pdev);
+        struct uart_omap_port *up = dev_get_drvdata(dev);
 
         if (up)
                 uart_suspend_port(&serial_omap_reg, &up->port);
         return 0;
 }
 
-static int serial_omap_resume(struct platform_device *dev)
+static int serial_omap_resume(struct device *dev)
 {
-        struct uart_omap_port *up = platform_get_drvdata(dev);
+        struct uart_omap_port *up = dev_get_drvdata(dev);
 
         if (up)
                 uart_resume_port(&serial_omap_reg, &up->port);
         return 0;
 }
+#endif
 
 static void serial_omap_rx_timeout(unsigned long uart_no)
 {
@@ -1135,6 +1203,7 @@ static int serial_omap_start_rxdma(struct uart_omap_port *up)
         int ret = 0;
 
         if (up->uart_dma.rx_dma_channel == -1) {
+                pm_runtime_get_sync(&up->pdev->dev);
                 ret = omap_request_dma(up->uart_dma.uart_dma_rx,
                                 "UART Rx DMA",
                                 (void *)uart_rx_dma_callback, up,
@@ -1299,6 +1368,14 @@ static int serial_omap_probe(struct platform_device *pdev)
                 up->uart_dma.rx_dma_channel = OMAP_UART_DMA_CH_FREE;
         }
 
+        pm_runtime_use_autosuspend(&pdev->dev);
+        pm_runtime_set_autosuspend_delay(&pdev->dev,
+                        OMAP_UART_AUTOSUSPEND_DELAY);
+
+        pm_runtime_irq_safe(&pdev->dev);
+        pm_runtime_enable(&pdev->dev);
+        pm_runtime_get_sync(&pdev->dev);
+
         ui[pdev->id] = up;
         serial_omap_add_console_port(up);
 
@@ -1306,6 +1383,7 @@ static int serial_omap_probe(struct platform_device *pdev)
         if (ret != 0)
                 goto do_release_region;
 
+        pm_runtime_put(&pdev->dev);
         platform_set_drvdata(pdev, up);
         return 0;
 err:
@@ -1320,22 +1398,40 @@ static int serial_omap_remove(struct platform_device *dev)
 {
         struct uart_omap_port *up = platform_get_drvdata(dev);
 
-        platform_set_drvdata(dev, NULL);
         if (up) {
+                pm_runtime_disable(&up->pdev->dev);
                 uart_remove_one_port(&serial_omap_reg, &up->port);
                 kfree(up);
         }
+
+        platform_set_drvdata(dev, NULL);
+        return 0;
+}
+
+#ifdef CONFIG_PM_RUNTIME
+static int serial_omap_runtime_suspend(struct device *dev)
+{
         return 0;
 }
 
+static int serial_omap_runtime_resume(struct device *dev)
+{
+        return 0;
+}
+#endif
+
+static const struct dev_pm_ops serial_omap_dev_pm_ops = {
+        SET_SYSTEM_SLEEP_PM_OPS(serial_omap_suspend, serial_omap_resume)
+        SET_RUNTIME_PM_OPS(serial_omap_runtime_suspend,
+                                serial_omap_runtime_resume, NULL)
+};
+
 static struct platform_driver serial_omap_driver = {
         .probe          = serial_omap_probe,
         .remove         = serial_omap_remove,
-
-        .suspend        = serial_omap_suspend,
-        .resume         = serial_omap_resume,
         .driver         = {
                 .name   = DRIVER_NAME,
+                .pm     = &serial_omap_dev_pm_ops,
         },
 };