u5500:USB: prevent sleep while usb host audio

While playing audio in usb host mode noise is observed,
The system wake up latency from sleep adds an extra
overhead when transferring ISO packets in host mode. Prevent
CPU from going to idle state when when there is high usb
activity in host mode.

ST-Ericsson ID: 373230
ST-Ericsson Linux next: NA
ST-Ericsson FOSS-OUT ID: Trivial

Change-Id: Ie60e21e58cdffce0e83b10ac50b4fbb5890c19cd
Signed-off-by: supriya karanth <supriya.karanth@stericsson.com>
Reviewed-on: http://gerrit.lud.stericsson.com/gerrit/44999
Reviewed-by: QATOOLS
Reviewed-by: Praveena NADAHALLY <praveen.nadahally@stericsson.com>
Reviewed-by: QABUILD
Reviewed-by: Rabin VINCENT <rabin.vincent@stericsson.com>

1 files changed, 58 insertions, 0 deletions

diff --git a/drivers/usb/otg/ab5500-usb.c b/drivers/usb/otg/ab5500-usb.c
index c57234d92be..1d38576a8f4 100644
--- a/drivers/usb/otg/ab5500-usb.c
+++ b/drivers/usb/otg/ab5500-usb.c
@@ -21,6 +21,7 @@
 #include <linux/kernel_stat.h>
 #include <mach/gpio.h>
 #include <mach/reboot_reasons.h>
+#include <linux/pm_qos_params.h>
 
 /* AB5500 USB macros
  */
@@ -46,6 +47,10 @@
 #define AB5500_USB_LINK_STATUS_MASK_V2		0xF8
 
 #define USB_PROBE_DELAY 1000 /* 1 seconds */
+#define USB_LIMIT (200) /* If we have more than 200 irqs per second */
+
+static struct pm_qos_request_list usb_pm_qos_latency;
+static bool usb_pm_qos_is_latency_0;
 
 #define PUBLIC_ID_BACKUPRAM1 (U5500_BACKUPRAM1_BASE + 0x0FC0)
 #define MAX_USB_SERIAL_NUMBER_LEN 31
@@ -145,6 +150,42 @@ static void ab5500_usb_wd_workaround(struct ab5500_usb *ab)
 		udelay(AB5500_WATCHDOG_DELAY_US);
 }
 
+static void ab5500_usb_load(struct work_struct *work)
+{
+	int cpu;
+	unsigned int num_irqs = 0;
+	static unsigned int old_num_irqs = UINT_MAX;
+	struct delayed_work *work_usb_workaround = to_delayed_work(work);
+	struct ab5500_usb *ab = container_of(work_usb_workaround,
+				struct ab5500_usb, work_usb_workaround);
+
+	for_each_online_cpu(cpu)
+	num_irqs += kstat_irqs_cpu(IRQ_DB5500_USBOTG, cpu);
+
+	if ((num_irqs > old_num_irqs) &&
+		(num_irqs - old_num_irqs) > USB_LIMIT) {
+
+		if (!usb_pm_qos_is_latency_0) {
+
+			pm_qos_add_request(&usb_pm_qos_latency,
+						PM_QOS_CPU_DMA_LATENCY, 0);
+			usb_pm_qos_is_latency_0 = true;
+		}
+	} else {
+
+		if (usb_pm_qos_is_latency_0) {
+
+				pm_qos_remove_request(&usb_pm_qos_latency);
+				usb_pm_qos_is_latency_0 = false;
+		}
+	}
+	old_num_irqs = num_irqs;
+
+	schedule_delayed_work_on(0,
+				&ab->work_usb_workaround,
+				msecs_to_jiffies(USB_PROBE_DELAY));
+}
+
 static void ab5500_usb_phy_enable(struct ab5500_usb *ab, bool sel_host)
 {
 	u8 bit;
@@ -166,6 +207,11 @@ static void ab5500_usb_phy_enable(struct ab5500_usb *ab, bool sel_host)
 	}
 
 	ux500_restore_context();
+	if (sel_host) {
+		schedule_delayed_work_on(0,
+					&ab->work_usb_workaround,
+					msecs_to_jiffies(USB_PROBE_DELAY));
+	}
 	abx500_mask_and_set_register_interruptible(ab->dev,
 			AB5500_BANK_USB,
 			AB5500_USB_PHY_CTRL_REG,
@@ -191,6 +237,15 @@ static void ab5500_usb_phy_disable(struct ab5500_usb *ab, bool sel_host)
 	clk_disable(ab->sysclk);
 	regulator_disable(ab->v_ape);
 	ab->usb_gpio->disable();
+
+	if (sel_host) {
+		if (usb_pm_qos_is_latency_0) {
+
+				pm_qos_remove_request(&usb_pm_qos_latency);
+				usb_pm_qos_is_latency_0 = false;
+		}
+		cancel_delayed_work_sync(&ab->work_usb_workaround);
+	}
 }
 
 #define ab5500_usb_peri_phy_en(ab)	ab5500_usb_phy_enable(ab, false)
@@ -724,6 +779,9 @@ static int __devinit ab5500_usb_probe(struct platform_device *pdev)
 	 */
 	INIT_DELAYED_WORK(&ab->dwork, ab5500_usb_delayed_work);
 
+	INIT_DELAYED_WORK_DEFERRABLE(&ab->work_usb_workaround,
+							ab5500_usb_load);
+
 	err = otg_set_transceiver(&ab->otg);
 	if (err)
 		dev_err(&pdev->dev, "Can't register transceiver\n");