From c6e126de43e7d4abfd6cf796b40589db3a046167 Mon Sep 17 00:00:00 2001 From: Pawel Moll Date: Thu, 15 May 2014 16:55:24 +0100 Subject: of: Keep track of populated platform devices In "Device Tree powered" systems, platform devices are usually massively populated with of_platform_populate() call, executed at some level of initcalls, either by generic architecture or by platform-specific code. There are situations though where certain devices must be created (and bound with drivers) before all the others. This presents a challenge, as devices created explicitly would be created again by of_platform_populate(). This patch tries to solve that issue in a generic way, adding a "populated" flag for a DT node description. Subsequent of_platform_populate() will skip such nodes (and its children) in a similar way to the non-available ones. This patch also adds of_platform_depopulate() as an operation complementary to the _populate() one. It removes a platform or an amba device populated from the Device Tree, together with its all children (leaving, however, devices without associated of_node untouched) clearing the "populated" flag on the way. Signed-off-by: Pawel Moll Reviewed-by: Rob Herring Acked-by: Grant Likely --- drivers/of/platform.c | 74 +++++++++++++++++++++++++++++++++++++++++++++++---- 1 file changed, 69 insertions(+), 5 deletions(-) (limited to 'drivers/of') diff --git a/drivers/of/platform.c b/drivers/of/platform.c index bd47fbc53dc9..e8376d646d98 100644 --- a/drivers/of/platform.c +++ b/drivers/of/platform.c @@ -206,12 +206,13 @@ static struct platform_device *of_platform_device_create_pdata( { struct platform_device *dev; - if (!of_device_is_available(np)) + if (!of_device_is_available(np) || + of_node_test_and_set_flag(np, OF_POPULATED)) return NULL; dev = of_device_alloc(np, bus_id, parent); if (!dev) - return NULL; + goto err_clear_flag; #if defined(CONFIG_MICROBLAZE) dev->archdata.dma_mask = 0xffffffffUL; @@ -229,10 +230,14 @@ static struct platform_device *of_platform_device_create_pdata( if (of_device_add(dev) != 0) { platform_device_put(dev); - return NULL; + goto err_clear_flag; } return dev; + +err_clear_flag: + of_node_clear_flag(np, OF_POPULATED); + return NULL; } /** @@ -264,14 +269,15 @@ static struct amba_device *of_amba_device_create(struct device_node *node, pr_debug("Creating amba device %s\n", node->full_name); - if (!of_device_is_available(node)) + if (!of_device_is_available(node) || + of_node_test_and_set_flag(node, OF_POPULATED)) return NULL; dev = amba_device_alloc(NULL, 0, 0); if (!dev) { pr_err("%s(): amba_device_alloc() failed for %s\n", __func__, node->full_name); - return NULL; + goto err_clear_flag; } /* setup generic device info */ @@ -311,6 +317,8 @@ static struct amba_device *of_amba_device_create(struct device_node *node, err_free: amba_device_put(dev); +err_clear_flag: + of_node_clear_flag(node, OF_POPULATED); return NULL; } #else /* CONFIG_ARM_AMBA */ @@ -487,4 +495,60 @@ int of_platform_populate(struct device_node *root, return rc; } EXPORT_SYMBOL_GPL(of_platform_populate); + +static int of_platform_device_destroy(struct device *dev, void *data) +{ + bool *children_left = data; + + /* Do not touch devices not populated from the device tree */ + if (!dev->of_node || !of_node_check_flag(dev->of_node, OF_POPULATED)) { + *children_left = true; + return 0; + } + + /* Recurse, but don't touch this device if it has any children left */ + if (of_platform_depopulate(dev) != 0) { + *children_left = true; + return 0; + } + + if (dev->bus == &platform_bus_type) + platform_device_unregister(to_platform_device(dev)); +#ifdef CONFIG_ARM_AMBA + else if (dev->bus == &amba_bustype) + amba_device_unregister(to_amba_device(dev)); +#endif + else { + *children_left = true; + return 0; + } + + of_node_clear_flag(dev->of_node, OF_POPULATED); + + return 0; +} + +/** + * of_platform_depopulate() - Remove devices populated from device tree + * @parent: device which childred will be removed + * + * Complementary to of_platform_populate(), this function removes children + * of the given device (and, recurrently, their children) that have been + * created from their respective device tree nodes (and only those, + * leaving others - eg. manually created - unharmed). + * + * Returns 0 when all children devices have been removed or + * -EBUSY when some children remained. + */ +int of_platform_depopulate(struct device *parent) +{ + bool children_left = false; + + device_for_each_child(parent, &children_left, + of_platform_device_destroy); + + return children_left ? -EBUSY : 0; +} +EXPORT_SYMBOL_GPL(of_platform_depopulate); + #endif /* CONFIG_OF_ADDRESS */ -- cgit v1.2.3