diff options
| -rw-r--r-- | drivers/amba/bus.c | 100 |
1 files changed, 90 insertions, 10 deletions
diff --git a/drivers/amba/bus.c b/drivers/amba/bus.c index f0099360039e..a5b5c87e2114 100644 --- a/drivers/amba/bus.c +++ b/drivers/amba/bus.c @@ -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 * |