Messages in this thread Patch in this message | | | From | Viresh Kumar <> | Subject | [PATCH V4 08/12] boot_constraint: Manage deferrable constraints | Date | Sun, 29 Oct 2017 19:18:56 +0530 |
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It is possible that some of the resources aren't available at the time constraints are getting set and the boot constraints core will return -EPROBE_DEFER for them. 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 <rnayak@codeaurora.org> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> --- drivers/base/dd.c | 12 ++ drivers/boot_constraints/Makefile | 2 +- drivers/boot_constraints/deferrable_dev.c | 235 ++++++++++++++++++++++++++++++ include/linux/boot_constraint.h | 14 ++ 4 files changed, 262 insertions(+), 1 deletion(-) create mode 100644 drivers/boot_constraints/deferrable_dev.c
diff --git a/drivers/base/dd.c b/drivers/base/dd.c index 4eec27fe2b2b..19eff5d08b9a 100644 --- a/drivers/base/dd.c +++ b/drivers/base/dd.c @@ -228,6 +228,18 @@ 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_constraints/Makefile b/drivers/boot_constraints/Makefile index b7ade1a7afb5..a765094623a3 100644 --- a/drivers/boot_constraints/Makefile +++ b/drivers/boot_constraints/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_constraints/deferrable_dev.c b/drivers/boot_constraints/deferrable_dev.c new file mode 100644 index 000000000000..04056f317aff --- /dev/null +++ b/drivers/boot_constraints/deferrable_dev.c @@ -0,0 +1,235 @@ +/* + * Copyright (C) 2017 Linaro. + * Viresh Kumar <viresh.kumar@linaro.org> + * + * This file is released under the GPLv2. + */ + +#define pr_fmt(fmt) "Boot Constraints: " fmt + +#include <linux/amba/bus.h> +#include <linux/err.h> +#include <linux/idr.h> +#include <linux/of.h> +#include <linux/of_platform.h> +#include <linux/platform_device.h> +#include <linux/slab.h> + +#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; + + if (of_device_is_compatible(np, "arm,primecell")) { + struct amba_device *adev = of_find_amba_device_by_node(np); + + if (!adev) { + pr_err("Failed to find amba dev: %s\n", np->full_name); + return; + } + dev = &adev->dev; + } else { + struct platform_device *pdev = of_find_device_by_node(np); + + if (!pdev) { + pr_err("Failed to find pdev: %s\n", np->full_name); + return; + } + dev = &pdev->dev; + } + + 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; +} + +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 637fe9d65536..c110b36e490f 100644 --- a/include/linux/boot_constraint.h +++ b/include/linux/boot_constraint.h @@ -35,6 +35,15 @@ struct dev_boot_constraint { void *data; }; +struct dev_boot_constraint_of { + const char *compat; + struct dev_boot_constraint *constraints; + unsigned int count; + + const char **dev_names; + unsigned int dev_names_count; +}; + struct dev_boot_constraint_info { struct dev_boot_constraint constraint; @@ -47,12 +56,17 @@ struct dev_boot_constraint_info { 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 -EINVAL; } static inline void dev_boot_constraints_remove(struct device *dev) {} +void dev_boot_constraint_add_deferrable_of(struct dev_boot_constraint_of *oconst, + int count) +{ } #endif /* CONFIG_DEV_BOOT_CONSTRAINTS */ #endif /* _LINUX_BOOT_CONSTRAINT_H */ -- 2.15.0.rc1.236.g92ea95045093
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