ARM: OMAP2+: UART: Remove omap_uart_can_sleep and add pm_qos

Omap_uart_can_sleep function blocks system wide low power state until
uart is active remove this func and add qos requests to prevent
MPU from transitioning.

Keep qos request to default value which will allow MPU to transition
and while uart baud rate is available calculate the latency value
from the baudrate and use the same to hold constraint while uart clocks
are enabled, and if uart is auto-idled the constraint is updated with
default constraint value allowing MPU to transition.

Qos requests are blocking notifier calls so put these requests to
work queue, also the driver uses irq_safe version of runtime API's
and callbacks can be called in interrupt disabled context.
So to avoid warn on slow path warning while using qos update
API's from runtime callbacks use the qos_work_queue.

During bootup the runtime_resume call backs might not be called and runtime
callback gets called only after uart is idled by setting the autosuspend
timeout. So qos_request from runtime resume callback might not activated during
boot if uart baudrate is calculated during bootup for console uart, so schedule
the qos_work queue once we calc_latency while configuring the uart port.

Flush and complete any pending qos jobs in work queue while suspending.

Signed-off-by: Govindraj.R <govindraj.raja@ti.com>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de> (for drivers/tty changes)
Signed-off-by: Kevin Hilman <khilman@ti.com>

diff --git a/arch/arm/mach-omap2/cpuidle34xx.c b/arch/arm/mach-omap2/cpuidle34xx.c
index e20332f4abdc57e891231bb39503b4dcb4d1aa18..3a9d2b883b345a9f3e5355b6ab7877517a91da90 100644 (file)
--- a/arch/arm/mach-omap2/cpuidle34xx.c
+++ b/arch/arm/mach-omap2/cpuidle34xx.c
@@ -30,7 +30,6 @@
 #include <plat/irqs.h>
 #include "powerdomain.h"
 #include "clockdomain.h"
-#include <plat/serial.h>
 
 #include "pm.h"
 #include "control.h"
@@ -245,11 +244,6 @@ static int omap3_enter_idle_bm(struct cpuidle_device *dev,
        struct omap3_idle_statedata *cx;
        int ret;
 
-       if (!omap3_can_sleep()) {
-               new_state_idx = drv->safe_state_index;
-               goto select_state;
-       }
-
        /*
         * Prevent idle completely if CAM is active.
         * CAM does not have wakeup capability in OMAP3.

diff --git a/arch/arm/mach-omap2/pm24xx.c b/arch/arm/mach-omap2/pm24xx.c
index 22af2f2fdbf92dbc5e670563859d18a22fe38c96..b8822f8b289184c46332732bc20ebe2ea5605cb3 100644 (file)
--- a/arch/arm/mach-omap2/pm24xx.c
+++ b/arch/arm/mach-omap2/pm24xx.c
@@ -222,8 +222,6 @@ static int omap2_can_sleep(void)
 {
        if (omap2_fclks_active())
                return 0;
-       if (!omap_uart_can_sleep())
-               return 0;
        if (osc_ck->usecount > 1)
                return 0;
        if (omap_dma_running())

diff --git a/arch/arm/mach-omap2/pm34xx.c b/arch/arm/mach-omap2/pm34xx.c
index 4feee45ef0692074e03303aa5ab6dcce5468c587..4ee5f4eb04e47656fd1793ed9f198d5ad44ccb37 100644 (file)
--- a/arch/arm/mach-omap2/pm34xx.c
+++ b/arch/arm/mach-omap2/pm34xx.c
@@ -35,7 +35,6 @@
 #include <plat/sram.h>
 #include "clockdomain.h"
 #include "powerdomain.h"
-#include <plat/serial.h>
 #include <plat/sdrc.h>
 #include <plat/prcm.h>
 #include <plat/gpmc.h>
@@ -456,21 +455,11 @@ void omap_sram_idle(void)
        clkdm_allow_idle(mpu_pwrdm->pwrdm_clkdms[0]);
 }
 
-int omap3_can_sleep(void)
-{
-       if (!omap_uart_can_sleep())
-               return 0;
-       return 1;
-}
-
 static void omap3_pm_idle(void)
 {
        local_irq_disable();
        local_fiq_disable();
 
-       if (!omap3_can_sleep())
-               goto out;
-
        if (omap_irq_pending() || need_resched())
                goto out;
 

diff --git a/arch/arm/mach-omap2/serial.c b/arch/arm/mach-omap2/serial.c
index c909770eacd12ae2db2dbe08cc7e960a8b34f7e4..247d89478f2439010c741045518d455e78e73d17 100644 (file)
--- a/arch/arm/mach-omap2/serial.c
+++ b/arch/arm/mach-omap2/serial.c
@@ -82,28 +82,6 @@ static struct omap_uart_port_info omap_serial_default_info[] __initdata = {
 };
 
 #ifdef CONFIG_PM
-
-int omap_uart_can_sleep(void)
-{
-       struct omap_uart_state *uart;
-       int can_sleep = 1;
-
-       list_for_each_entry(uart, &uart_list, node) {
-               if (!uart->clocked)
-                       continue;
-
-               if (!uart->can_sleep) {
-                       can_sleep = 0;
-                       continue;
-               }
-
-               /* This UART can now safely sleep. */
-               omap_uart_allow_sleep(uart);
-       }
-
-       return can_sleep;
-}
-
 static void omap_uart_enable_wakeup(struct platform_device *pdev, bool enable)
 {
        struct omap_device *od = to_omap_device(pdev);

diff --git a/arch/arm/plat-omap/include/plat/omap-serial.h b/arch/arm/plat-omap/include/plat/omap-serial.h
index ea63b2bc761c4014ca71ca75a1024e9cdd353388..9ff444469f3d9a1add04cda94c4b7d9247b5ea4a 100644 (file)
--- a/arch/arm/plat-omap/include/plat/omap-serial.h
+++ b/arch/arm/plat-omap/include/plat/omap-serial.h
@@ -19,6 +19,7 @@
 
 #include <linux/serial_core.h>
 #include <linux/platform_device.h>
+#include <linux/pm_qos.h>
 
 #include <plat/mux.h>
 
@@ -130,6 +131,11 @@ struct uart_omap_port {
        u32                     context_loss_cnt;
        u32                     errata;
        u8                      wakeups_enabled;
+
+       struct pm_qos_request   pm_qos_request;
+       u32                     latency;
+       u32                     calc_latency;
+       struct work_struct      qos_work;
 };
 
 #endif /* __OMAP_SERIAL_H__ */

diff --git a/drivers/tty/serial/omap-serial.c b/drivers/tty/serial/omap-serial.c
index e1eaa66c047b9bea6f03c7b4ca156a4e7fe89137..f3ff0ca377c585c6975f9eb3509d74905341d52f 100644 (file)
--- a/drivers/tty/serial/omap-serial.c
+++ b/drivers/tty/serial/omap-serial.c
@@ -51,6 +51,8 @@ static void serial_omap_rxdma_poll(unsigned long uart_no);
 static int serial_omap_start_rxdma(struct uart_omap_port *up);
 static void serial_omap_mdr1_errataset(struct uart_omap_port *up, u8 mdr1);
 
+static struct workqueue_struct *serial_omap_uart_wq;
+
 static inline unsigned int serial_in(struct uart_omap_port *up, int offset)
 {
        offset <<= up->port.regshift;
@@ -671,6 +673,14 @@ serial_omap_configure_xonxoff
        serial_out(up, UART_LCR, up->lcr);
 }
 
+static void serial_omap_uart_qos_work(struct work_struct *work)
+{
+       struct uart_omap_port *up = container_of(work, struct uart_omap_port,
+                                               qos_work);
+
+       pm_qos_update_request(&up->pm_qos_request, up->latency);
+}
+
 static void
 serial_omap_set_termios(struct uart_port *port, struct ktermios *termios,
                        struct ktermios *old)
@@ -711,6 +721,12 @@ serial_omap_set_termios(struct uart_port *port, struct ktermios *termios,
        baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk/13);
        quot = serial_omap_get_divisor(port, baud);
 
+       /* calculate wakeup latency constraint */
+       up->calc_latency = (1000000 * up->port.fifosize) /
+                               (1000 * baud / 8);
+       up->latency = up->calc_latency;
+       schedule_work(&up->qos_work);
+
        up->dll = quot & 0xff;
        up->dlh = quot >> 8;
        up->mdr1 = UART_OMAP_MDR1_DISABLE;
@@ -1145,8 +1161,11 @@ static int serial_omap_suspend(struct device *dev)
 {
        struct uart_omap_port *up = dev_get_drvdata(dev);
 
-       if (up)
+       if (up) {
                uart_suspend_port(&serial_omap_reg, &up->port);
+               flush_work_sync(&up->qos_work);
+       }
+
        return 0;
 }
 
@@ -1383,6 +1402,13 @@ static int serial_omap_probe(struct platform_device *pdev)
                up->uart_dma.rx_dma_channel = OMAP_UART_DMA_CH_FREE;
        }
 
+       up->latency = PM_QOS_CPU_DMA_LAT_DEFAULT_VALUE;
+       up->calc_latency = PM_QOS_CPU_DMA_LAT_DEFAULT_VALUE;
+       pm_qos_add_request(&up->pm_qos_request,
+               PM_QOS_CPU_DMA_LATENCY, up->latency);
+       serial_omap_uart_wq = create_singlethread_workqueue(up->name);
+       INIT_WORK(&up->qos_work, serial_omap_uart_qos_work);
+
        pm_runtime_use_autosuspend(&pdev->dev);
        pm_runtime_set_autosuspend_delay(&pdev->dev,
                        omap_up_info->autosuspend_timeout);
@@ -1416,6 +1442,8 @@ static int serial_omap_remove(struct platform_device *dev)
        if (up) {
                pm_runtime_disable(&up->pdev->dev);
                uart_remove_one_port(&serial_omap_reg, &up->port);
+               pm_qos_remove_request(&up->pm_qos_request);
+
                kfree(up);
        }
 
@@ -1518,6 +1546,9 @@ static int serial_omap_runtime_suspend(struct device *dev)
                        (up->errata & UART_ERRATA_i291_DMA_FORCEIDLE))
                pdata->set_forceidle(up->pdev);
 
+       up->latency = PM_QOS_CPU_DMA_LAT_DEFAULT_VALUE;
+       schedule_work(&up->qos_work);
+
        return 0;
 }
 
@@ -1538,6 +1569,9 @@ static int serial_omap_runtime_resume(struct device *dev)
                if (up->use_dma && pdata->set_noidle &&
                                (up->errata & UART_ERRATA_i291_DMA_FORCEIDLE))
                        pdata->set_noidle(up->pdev);
+
+               up->latency = up->calc_latency;
+               schedule_work(&up->qos_work);
        }
 
        return 0;