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In order to retry adding the constraints at a later point of time (after the resource is added and before any of its users come up), this patch proposes two things: - Each constraint is represented by a virtual platform device, so that it is re-probed again until the time all the dependencies aren't met. The platform device is removed along with the constraint, with help of the free_resources() callback. - Enable early defer probing support by calling driver_enable_deferred_probe(), so that the core retries probing deferred devices every time any device is bound to a driver. This makes sure that the constraint is set before any of the users of the resources come up. This is tested on ARM64 Hikey board where probe was deferred for a device. Tested-by: Rajendra Nayak Signed-off-by: Viresh Kumar --- drivers/base/dd.c | 12 ++ drivers/boot_constraint/Makefile | 2 +- drivers/boot_constraint/deferrable_dev.c | 241 +++++++++++++++++++++++++++++++ include/linux/boot_constraint.h | 27 ++++ 4 files changed, 281 insertions(+), 1 deletion(-) create mode 100644 drivers/boot_constraint/deferrable_dev.c diff --git a/drivers/base/dd.c b/drivers/base/dd.c index dc89f98a2487..48a9945ff206 100644 --- a/drivers/base/dd.c +++ b/drivers/base/dd.c @@ -227,6 +227,18 @@ void device_unblock_probing(void) driver_deferred_probe_trigger(); } +/** + * driver_enable_deferred_probe() - Enable probing of deferred devices + * + * We don't want to get in the way when the bulk of drivers are getting probed + * and so deferred probe is disabled in the beginning. Enable it now because we + * need it. + */ +void driver_enable_deferred_probe(void) +{ + driver_deferred_probe_enable = true; +} + /** * deferred_probe_initcall() - Enable probing of deferred devices * diff --git a/drivers/boot_constraint/Makefile b/drivers/boot_constraint/Makefile index b7ade1a7afb5..a765094623a3 100644 --- a/drivers/boot_constraint/Makefile +++ b/drivers/boot_constraint/Makefile @@ -1,3 +1,3 @@ # Makefile for device boot constraints -obj-y := clk.o core.o pm.o supply.o +obj-y := clk.o deferrable_dev.o core.o pm.o supply.o diff --git a/drivers/boot_constraint/deferrable_dev.c b/drivers/boot_constraint/deferrable_dev.c new file mode 100644 index 000000000000..158c04d41e09 --- /dev/null +++ b/drivers/boot_constraint/deferrable_dev.c @@ -0,0 +1,241 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2017 Linaro. + * Viresh Kumar + */ + +#include +#include +#include +#include +#include +#include + +#include "core.h" + +static DEFINE_IDA(pdev_index); + +void driver_enable_deferred_probe(void); + +struct boot_constraint_pdata { + struct device *dev; + struct dev_boot_constraint constraint; + int probe_failed; + int index; +}; + +static void boot_constraint_remove(void *data) +{ + struct platform_device *pdev = data; + struct boot_constraint_pdata *pdata = dev_get_platdata(&pdev->dev); + + ida_simple_remove(&pdev_index, pdata->index); + kfree(pdata->constraint.data); + platform_device_unregister(pdev); +} + +/* + * A platform device is added for each and every constraint, to handle + * -EPROBE_DEFER properly. + */ +static int boot_constraint_probe(struct platform_device *pdev) +{ + struct boot_constraint_pdata *pdata = dev_get_platdata(&pdev->dev); + struct dev_boot_constraint_info info; + int ret; + + if (WARN_ON(!pdata)) + return -EINVAL; + + info.constraint = pdata->constraint; + info.free_resources = boot_constraint_remove; + info.free_resources_data = pdev; + + ret = dev_boot_constraint_add(pdata->dev, &info); + if (ret) { + if (ret == -EPROBE_DEFER) + driver_enable_deferred_probe(); + else + pdata->probe_failed = ret; + } + + return ret; +} + +static struct platform_driver boot_constraint_driver = { + .driver = { + .name = "boot-constraints-dev", + }, + .probe = boot_constraint_probe, +}; + +static int __init boot_constraint_init(void) +{ + return platform_driver_register(&boot_constraint_driver); +} +core_initcall(boot_constraint_init); + +static int boot_constraint_add_dev(struct device *dev, + struct dev_boot_constraint *constraint) +{ + struct boot_constraint_pdata pdata = { + .dev = dev, + .constraint.type = constraint->type, + }; + struct platform_device *pdev; + struct boot_constraint_pdata *pdev_pdata; + int size, ret; + + switch (constraint->type) { + case DEV_BOOT_CONSTRAINT_CLK: + size = sizeof(struct dev_boot_constraint_clk_info); + break; + case DEV_BOOT_CONSTRAINT_PM: + size = 0; + break; + case DEV_BOOT_CONSTRAINT_SUPPLY: + size = sizeof(struct dev_boot_constraint_supply_info); + break; + default: + dev_err(dev, "%s: Constraint type (%d) not supported\n", + __func__, constraint->type); + return -EINVAL; + } + + /* Will be freed from boot_constraint_remove() */ + pdata.constraint.data = kmemdup(constraint->data, size, GFP_KERNEL); + if (!pdata.constraint.data) + return -ENOMEM; + + ret = ida_simple_get(&pdev_index, 0, 256, GFP_KERNEL); + if (ret < 0) { + dev_err(dev, "failed to allocate index (%d)\n", ret); + goto free; + } + + pdata.index = ret; + + pdev = platform_device_register_data(NULL, "boot-constraints-dev", ret, + &pdata, sizeof(pdata)); + if (IS_ERR(pdev)) { + dev_err(dev, "%s: Failed to create pdev (%ld)\n", __func__, + PTR_ERR(pdev)); + ret = PTR_ERR(pdev); + goto ida_remove; + } + + /* Release resources if probe has failed */ + pdev_pdata = dev_get_platdata(&pdev->dev); + if (pdev_pdata->probe_failed) { + ret = pdev_pdata->probe_failed; + goto remove_pdev; + } + + return 0; + +remove_pdev: + platform_device_unregister(pdev); +ida_remove: + ida_simple_remove(&pdev_index, pdata.index); +free: + kfree(pdata.constraint.data); + + return ret; +} + +static int dev_boot_constraint_add_deferrable(struct device *dev, + struct dev_boot_constraint *constraints, int count) +{ + int ret, i; + + for (i = 0; i < count; i++) { + ret = boot_constraint_add_dev(dev, &constraints[i]); + if (ret) + return ret; + } + + return 0; +} + +/* This only creates platform devices for now */ +static void add_deferrable_of_single(struct device_node *np, + struct dev_boot_constraint *constraints, + int count) +{ + struct device *dev; + int ret; + + if (!of_device_is_available(np)) + return; + + ret = of_platform_bus_create(np, NULL, NULL, NULL, false); + if (ret) + return; + + dev = of_find_any_device_by_node(np); + if (!dev) { + pr_err("Boot Constraints: Failed to find dev: %pOF\n", np); + return; + } + + ret = dev_boot_constraint_add_deferrable(dev, constraints, count); + if (ret) + dev_err(dev, "Failed to add boot constraint (%d)\n", ret); +} + +/* Not all compatible device nodes may have boot constraints */ +static bool node_has_boot_constraints(struct device_node *np, + struct dev_boot_constraint_of *oconst) +{ + int i; + + if (!oconst->dev_names) + return true; + + for (i = 0; i < oconst->dev_names_count; i++) { + if (!strcmp(oconst->dev_names[i], kbasename(np->full_name))) + return true; + } + + return false; +} + +/** + * dev_boot_constraint_add_deferrable_of: Adds all constraints for a platform. + * + * @oconst: This is an array of 'struct dev_boot_constraint_of', where each + * entry of the array is used to add one or more boot constraints across one or + * more devices having the same compatibility in the device tree. + * @count: Size of the 'oconst' array. + * + * This helper routine provides an easy way to add all boot constraints for a + * machine or platform. Just like dev_boot_constraint_add(), this must be called + * before the devices (to which we want to add constraints) are probed by their + * drivers, otherwise the boot constraint will never get removed for those + * devices and may result in unwanted behavior of the hardware. The boot + * constraints are removed by the driver core automatically after the devices + * are probed (successfully or unsuccessfully). + * + * This adds the boot constraints in a deferrable way and the caller need not + * worry about the availability of the resources required by the constraint. + * This routine will return successfully and the constraint will be added by the + * boot constraint core as soon as the resource is available at a later point in + * time. + */ +void dev_boot_constraint_add_deferrable_of(struct dev_boot_constraint_of *oconst, + int count) +{ + struct device_node *np; + int i; + + for (i = 0; i < count; i++) { + for_each_compatible_node(np, NULL, oconst[i].compat) { + if (!node_has_boot_constraints(np, &oconst[i])) + continue; + + add_deferrable_of_single(np, oconst[i].constraints, + oconst[i].count); + } + } +} +EXPORT_SYMBOL_GPL(dev_boot_constraint_add_deferrable_of); diff --git a/include/linux/boot_constraint.h b/include/linux/boot_constraint.h index 12fac0d565b0..ab752e19bfd0 100644 --- a/include/linux/boot_constraint.h +++ b/include/linux/boot_constraint.h @@ -79,16 +79,43 @@ struct dev_boot_constraint_info { void *free_resources_data; }; +/** + * struct dev_boot_constraint_of - This is used to add one or more boot + * constraints across one or more devices having the same compatibility in the + * device tree. + * + * @compat: This must match the compatible string of the devices to which we + * want to apply constraints. + * @constraints: This points to one or more boot constraints. + * @count: This contains the number of boot constraints pointed by the + * 'constraints' field. + * @dev_names: This is used to limit the application of boot constraints to only + * a subset of devices with matching compatibility. + * @dev_names_count: This is the number of devices pointed by the 'dev_names' + * array. + */ +struct dev_boot_constraint_of { + const char *compat; + struct dev_boot_constraint *constraints; + unsigned int count; + + const char * const *dev_names; + unsigned int dev_names_count; +}; + #ifdef CONFIG_DEV_BOOT_CONSTRAINT int dev_boot_constraint_add(struct device *dev, struct dev_boot_constraint_info *info); void dev_boot_constraints_remove(struct device *dev); +void dev_boot_constraint_add_deferrable_of(struct dev_boot_constraint_of *oconst, + int count); #else static inline int dev_boot_constraint_add(struct device *dev, struct dev_boot_constraint_info *info) { return 0; } static inline void dev_boot_constraints_remove(struct device *dev) {} +static inline void dev_boot_constraint_add_deferrable_of(struct dev_boot_constraint_of *oconst, int count) {} #endif /* CONFIG_DEV_BOOT_CONSTRAINT */ #endif /* _LINUX_BOOT_CONSTRAINT_H */