ARM: 8566/1: drivers: amba: properly handle devices with power domains (a41980f2) · Commits · 戴 / test

drivers/amba/bus.c

+90 −10

Original line number	Diff line number	Diff line
		@@ -336,16 +336,7 @@ static void amba_device_release(struct device *dev)
		kfree(d);
		}

		/**
		* amba_device_add - add a previously allocated AMBA device structure
		* @dev: AMBA device allocated by amba_device_alloc
		* @parent: resource parent for this devices resources
		*
		* Claim the resource, and read the device cell ID if not already
		* initialized. Register the AMBA device with the Linux device
		* manager.
		*/
		int amba_device_add(struct amba_device dev, struct resource parent)
		static int amba_device_try_add(struct amba_device dev, struct resource parent)
		{
		u32 size;
		void __iomem *tmp;
		@@ -373,6 +364,12 @@ int amba_device_add(struct amba_device dev, struct resource parent)
		goto err_release;
		}

		ret = dev_pm_domain_attach(&dev->dev, true);
		if (ret == -EPROBE_DEFER) {
		iounmap(tmp);
		goto err_release;
		}

		ret = amba_get_enable_pclk(dev);
		if (ret == 0) {
		u32 pid, cid;
		@@ -398,6 +395,7 @@ int amba_device_add(struct amba_device dev, struct resource parent)
		}

		iounmap(tmp);
		dev_pm_domain_detach(&dev->dev, true);

		if (ret)
		goto err_release;
		@@ -421,6 +419,88 @@ int amba_device_add(struct amba_device dev, struct resource parent)
		err_out:
		return ret;
		}

		/*
		* Registration of AMBA device require reading its pid and cid registers.
		* To do this, the device must be turned on (if it is a part of power domain)
		* and have clocks enabled. However in some cases those resources might not be
		* yet available. Returning EPROBE_DEFER is not a solution in such case,
		* because callers don't handle this special error code. Instead such devices
		* are added to the special list and their registration is retried from
		* periodic worker, until all resources are available and registration succeeds.
		*/
		struct deferred_device {
		struct amba_device *dev;
		struct resource *parent;
		struct list_head node;
		};

		static LIST_HEAD(deferred_devices);
		static DEFINE_MUTEX(deferred_devices_lock);

		static void amba_deferred_retry_func(struct work_struct *dummy);
		static DECLARE_DELAYED_WORK(deferred_retry_work, amba_deferred_retry_func);

		#define DEFERRED_DEVICE_TIMEOUT (msecs_to_jiffies(5 * 1000))

		static void amba_deferred_retry_func(struct work_struct *dummy)
		{
		struct deferred_device ddev, tmp;

		mutex_lock(&deferred_devices_lock);

		list_for_each_entry_safe(ddev, tmp, &deferred_devices, node) {
		int ret = amba_device_try_add(ddev->dev, ddev->parent);

		if (ret == -EPROBE_DEFER)
		continue;

		list_del_init(&ddev->node);
		kfree(ddev);
		}

		if (!list_empty(&deferred_devices))
		schedule_delayed_work(&deferred_retry_work,
		DEFERRED_DEVICE_TIMEOUT);

		mutex_unlock(&deferred_devices_lock);
		}

		/**
		* amba_device_add - add a previously allocated AMBA device structure
		* @dev: AMBA device allocated by amba_device_alloc
		* @parent: resource parent for this devices resources
		*
		* Claim the resource, and read the device cell ID if not already
		* initialized. Register the AMBA device with the Linux device
		* manager.
		*/
		int amba_device_add(struct amba_device dev, struct resource parent)
		{
		int ret = amba_device_try_add(dev, parent);

		if (ret == -EPROBE_DEFER) {
		struct deferred_device *ddev;

		ddev = kmalloc(sizeof(*ddev), GFP_KERNEL);
		if (!ddev)
		return -ENOMEM;

		ddev->dev = dev;
		ddev->parent = parent;
		ret = 0;

		mutex_lock(&deferred_devices_lock);

		if (list_empty(&deferred_devices))
		schedule_delayed_work(&deferred_retry_work,
		DEFERRED_DEVICE_TIMEOUT);
		list_add_tail(&ddev->node, &deferred_devices);

		mutex_unlock(&deferred_devices_lock);
		}
		return ret;
		}
		EXPORT_SYMBOL_GPL(amba_device_add);

		static struct amba_device *

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