greybus: arche-platform: Fix boot, poweroff and fw_flashing seq with APBs

Now SVC driver has an access to APBs operational functions
(coldboot, standby_boot, fw_flashing and poweroff), SVC driver
can control APB's as per below rules,

 - If SVC goes down (poweroff state), it will also power off APBs
   and vice a versa for all operational states.
 - On boot, SVC will probe/populate APB device, but will not coldboot
   it. APBs will coldboot only after handshaking with SVC over
   wake/detect line.
   Note that, both APBs share same wake/detect line.

So from user/developer perspective, it is highly recommended that
they should use arche-platform interfaces, instead of individual
apb interface,

 # echo [off/active/standby/fw_flashing] > /sys/devices/arche_platform.*/state

Note: 'standby' mode is not supported as of now.

Testing Done: Testd on EVT1.2 and DB3.5 platform.

Signed-off-by: Vaibhav Hiremath <vaibhav.hiremath@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>

diff --git a/drivers/staging/greybus/arche-platform.c b/drivers/staging/greybus/arche-platform.c
index 3e6432f0f1bc029be7473cdf68eb58820f5baf42..037e1420605961b1c28c2d78788c0ca84f9d6de0 100644 (file)
--- a/drivers/staging/greybus/arche-platform.c
+++ b/drivers/staging/greybus/arche-platform.c
@@ -45,6 +45,37 @@ static inline void svc_reset_onoff(unsigned int gpio, bool onoff)
        gpio_set_value(gpio, onoff);
 }
 
+static int apb_cold_boot(struct device *dev, void *data)
+{
+       int ret;
+
+       ret = apb_ctrl_coldboot(dev);
+       if (ret)
+               dev_warn(dev, "failed to coldboot\n");
+
+       /*Child nodes are independent, so do not exit coldboot operation */
+       return 0;
+}
+
+static int apb_fw_flashing_state(struct device *dev, void *data)
+{
+       int ret;
+
+       ret = apb_ctrl_fw_flashing(dev);
+       if (ret)
+               dev_warn(dev, "failed to switch to fw flashing state\n");
+
+       /*Child nodes are independent, so do not exit coldboot operation */
+       return 0;
+}
+
+static int apb_poweroff(struct device *dev, void *data)
+{
+       apb_ctrl_poweroff(dev);
+
+       return 0;
+}
+
 /**
  * svc_delayed_work - Time to give SVC to boot.
  */
@@ -52,10 +83,7 @@ static void svc_delayed_work(struct work_struct *work)
 {
        struct arche_platform_drvdata *arche_pdata =
                container_of(work, struct arche_platform_drvdata, delayed_work.work);
-       struct device *dev = arche_pdata->dev;
-       struct device_node *np = dev->of_node;
        int timeout = 50;
-       int ret;
 
        /*
         * 1.   SVC and AP boot independently, with AP<-->SVC wake/detect pin
@@ -79,18 +107,20 @@ static void svc_delayed_work(struct work_struct *work)
                msleep(100);
        } while(timeout--);
 
-       if (timeout >= 0) {
-               ret = of_platform_populate(np, NULL, NULL, dev);
-               if (!ret) {
-                       /* re-assert wake_detect to confirm SVC WAKE_OUT */
-                       gpio_direction_output(arche_pdata->wake_detect_gpio, 1);
-                       return;
-               }
+       if (timeout < 0) {
+               /* FIXME: We may want to limit retries here */
+               dev_warn(arche_pdata->dev,
+                       "Timed out on wake/detect, rescheduling handshake\n");
+               gpio_direction_output(arche_pdata->wake_detect_gpio, 0);
+               schedule_delayed_work(&arche_pdata->delayed_work, msecs_to_jiffies(2000));
+               return;
        }
 
-       /* FIXME: We may want to limit retries here */
-       gpio_direction_output(arche_pdata->wake_detect_gpio, 0);
-       schedule_delayed_work(&arche_pdata->delayed_work, msecs_to_jiffies(2000));
+       /* Bring APB out of reset: cold boot sequence */
+       device_for_each_child(arche_pdata->dev, NULL, apb_cold_boot);
+
+       /* re-assert wake_detect to confirm SVC WAKE_OUT */
+       gpio_direction_output(arche_pdata->wake_detect_gpio, 1);
 }
 
 /* Export gpio's to user space */
@@ -176,12 +206,17 @@ static ssize_t state_store(struct device *dev,
                if (arche_pdata->state == ARCHE_PLATFORM_STATE_OFF)
                        return count;
 
+               /*  If SVC goes down, bring down APB's as well */
+               device_for_each_child(arche_pdata->dev, NULL, apb_poweroff);
+
                arche_platform_poweroff_seq(arche_pdata);
        } else if (sysfs_streq(buf, "active")) {
                if (arche_pdata->state == ARCHE_PLATFORM_STATE_ACTIVE)
                        return count;
 
                ret = arche_platform_coldboot_seq(arche_pdata);
+               /* Give enough time for SVC to boot and then handshake with SVC */
+               schedule_delayed_work(&arche_pdata->delayed_work, msecs_to_jiffies(2000));
        } else if (sysfs_streq(buf, "standby")) {
                if (arche_pdata->state == ARCHE_PLATFORM_STATE_STANDBY)
                        return count;
@@ -193,8 +228,13 @@ static ssize_t state_store(struct device *dev,
 
                /* First we want to make sure we power off everything
                 * and then enter FW flashing state */
+               device_for_each_child(arche_pdata->dev, NULL, apb_poweroff);
+
                arche_platform_poweroff_seq(arche_pdata);
+
                arche_platform_fw_flashing_seq(arche_pdata);
+
+               device_for_each_child(arche_pdata->dev, NULL, apb_fw_flashing_state);
        } else {
                dev_err(arche_pdata->dev, "unknown state\n");
                ret = -EINVAL;
@@ -321,8 +361,6 @@ static int arche_platform_probe(struct platform_device *pdev)
        gpio_direction_output(arche_pdata->wake_detect_gpio, 0);
 
        arche_pdata->dev = &pdev->dev;
-       INIT_DELAYED_WORK(&arche_pdata->delayed_work, svc_delayed_work);
-       schedule_delayed_work(&arche_pdata->delayed_work, msecs_to_jiffies(2000));
 
        ret = device_create_file(dev, &dev_attr_state);
        if (ret) {
@@ -336,6 +374,15 @@ static int arche_platform_probe(struct platform_device *pdev)
                return ret;
        }
 
+       ret = of_platform_populate(np, NULL, NULL, dev);
+       if (ret) {
+               dev_err(dev, "failed to populate child nodes %d\n", ret);
+               return ret;
+       }
+
+       INIT_DELAYED_WORK(&arche_pdata->delayed_work, svc_delayed_work);
+       schedule_delayed_work(&arche_pdata->delayed_work, msecs_to_jiffies(2000));
+
        export_gpios(arche_pdata);
 
        dev_info(dev, "Device registered successfully\n");