cpufreq: brcmstb-avs-cpufreq: Support polling AVS firmware

In case the interrupt towards the host is never raised, yet the AVS
firmware responds correctly within the alloted time, allow supporting a
polling mode.

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Markus Mayer <mmayer@broadcom.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

diff --git a/drivers/cpufreq/brcmstb-avs-cpufreq.c b/drivers/cpufreq/brcmstb-avs-cpufreq.c
index c8b7546..79a0538 100644 (file)
--- a/drivers/cpufreq/brcmstb-avs-cpufreq.c
+++ b/drivers/cpufreq/brcmstb-avs-cpufreq.c
@@ -42,6 +42,7 @@
  */
 
 #include <linux/cpufreq.h>
+#include <linux/delay.h>
 #include <linux/interrupt.h>
 #include <linux/io.h>
 #include <linux/module.h>
@@ -178,6 +179,7 @@ struct private_data {
        struct completion done;
        struct semaphore sem;
        struct pmap pmap;
+       int host_irq;
 };
 
 static void __iomem *__map_region(const char *name)
@@ -195,12 +197,36 @@ static void __iomem *__map_region(const char *name)
        return ptr;
 }
 
+static unsigned long wait_for_avs_command(struct private_data *priv,
+                                         unsigned long timeout)
+{
+       unsigned long time_left = 0;
+       u32 val;
+
+       /* Event driven, wait for the command interrupt */
+       if (priv->host_irq >= 0)
+               return wait_for_completion_timeout(&priv->done,
+                                                  msecs_to_jiffies(timeout));
+
+       /* Polling for command completion */
+       do {
+               time_left = timeout;
+               val = readl(priv->base + AVS_MBOX_STATUS);
+               if (val)
+                       break;
+
+               usleep_range(1000, 2000);
+       } while (--timeout);
+
+       return time_left;
+}
+
 static int __issue_avs_command(struct private_data *priv, unsigned int cmd,
                               unsigned int num_in, unsigned int num_out,
                               u32 args[])
 {
-       unsigned long time_left = msecs_to_jiffies(AVS_TIMEOUT);
        void __iomem *base = priv->base;
+       unsigned long time_left;
        unsigned int i;
        int ret;
        u32 val;
@@ -238,7 +264,7 @@ static int __issue_avs_command(struct private_data *priv, unsigned int cmd,
        writel(AVS_CPU_L2_INT_MASK, priv->avs_intr_base + AVS_CPU_L2_SET0);
 
        /* Wait for AVS co-processor to finish processing the command. */
-       time_left = wait_for_completion_timeout(&priv->done, time_left);
+       time_left = wait_for_avs_command(priv, AVS_TIMEOUT);
 
        /*
         * If the AVS status is not in the expected range, it means AVS didn't
@@ -509,7 +535,7 @@ static int brcm_avs_prepare_init(struct platform_device *pdev)
 {
        struct private_data *priv;
        struct device *dev;
-       int host_irq, ret;
+       int ret;
 
        dev = &pdev->dev;
        priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
@@ -536,19 +562,14 @@ static int brcm_avs_prepare_init(struct platform_device *pdev)
                goto unmap_base;
        }
 
-       host_irq = platform_get_irq_byname(pdev, BRCM_AVS_HOST_INTR);
-       if (host_irq < 0) {
-               dev_err(dev, "Couldn't find interrupt %s -- %d\n",
-                       BRCM_AVS_HOST_INTR, host_irq);
-               ret = host_irq;
-               goto unmap_intr_base;
-       }
+       priv->host_irq = platform_get_irq_byname(pdev, BRCM_AVS_HOST_INTR);
 
-       ret = devm_request_irq(dev, host_irq, irq_handler, IRQF_TRIGGER_RISING,
+       ret = devm_request_irq(dev, priv->host_irq, irq_handler,
+                              IRQF_TRIGGER_RISING,
                               BRCM_AVS_HOST_INTR, priv);
-       if (ret) {
+       if (ret && priv->host_irq >= 0) {
                dev_err(dev, "IRQ request failed: %s (%d) -- %d\n",
-                       BRCM_AVS_HOST_INTR, host_irq, ret);
+                       BRCM_AVS_HOST_INTR, priv->host_irq, ret);
                goto unmap_intr_base;
        }