From 608f26c51bebc68db7f2edc7590ee513d2bc5465 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Sat, 25 Jul 2015 21:52:35 +0900 Subject: devres: introduce Devres (Managed Device Resource) framework In U-Boot's driver model, memory is basically allocated and freed in the core framework. So, low level drivers generally only have to specify the size of needed memory with .priv_auto_alloc_size, .platdata_auto_alloc_size, etc. Nevertheless, some drivers still need to allocate/free memory on their own in case they cannot statically know the necessary memory size. So, I believe it is reasonable enough to port Devres into U-boot. Devres, which originates in Linux, manages device resources for each device and automatically releases them on driver detach. With devres, device resources are guaranteed to be freed whether initialization fails half-way or the device gets detached. The basic idea is totally the same to that of Linux, but I tweaked it a bit so that it fits in U-Boot's driver model. In U-Boot, drivers are activated in two steps: binding and probing. Binding puts a driver and a device together. It is just data manipulation on the system memory, so nothing has happened on the hardware device at this moment. When the device is really used, it is probed. Probing initializes the real hardware device to make it really ready for use. So, the resources acquired during the probing process must be freed when the device is removed. Likewise, what has been allocated in binding should be released when the device is unbound. The struct devres has a member "probe" to remember when the resource was allocated. CONFIG_DEBUG_DEVRES is also supported for easier debugging. If enabled, debug messages are printed each time a resource is allocated/freed. Signed-off-by: Masahiro Yamada Acked-by: Simon Glass --- drivers/core/Kconfig | 10 +++ drivers/core/Makefile | 2 +- drivers/core/device-remove.c | 5 ++ drivers/core/device.c | 3 + drivers/core/devres.c | 196 +++++++++++++++++++++++++++++++++++++++++++ 5 files changed, 215 insertions(+), 1 deletion(-) create mode 100644 drivers/core/devres.c (limited to 'drivers/core') diff --git a/drivers/core/Kconfig b/drivers/core/Kconfig index 5d0e949..a002d69 100644 --- a/drivers/core/Kconfig +++ b/drivers/core/Kconfig @@ -78,3 +78,13 @@ config SYSCON as a group by a single driver. Some common functionality is provided by this uclass, including accessing registers via regmap and assigning a unique number to each. + +config DEBUG_DEVRES + bool "Managed device resources verbose debug messages" + depends on DM + help + If this option is enabled, devres debug messages are printed. + Select this if you are having a problem with devres or want to + debug resource management for a managed device. + + If you are unsure about this, Say N here. diff --git a/drivers/core/Makefile b/drivers/core/Makefile index ce3027a..260833e 100644 --- a/drivers/core/Makefile +++ b/drivers/core/Makefile @@ -4,7 +4,7 @@ # SPDX-License-Identifier: GPL-2.0+ # -obj-y += device.o lists.o root.o uclass.o util.o +obj-y += device.o lists.o root.o uclass.o util.o devres.o ifndef CONFIG_SPL_BUILD obj-$(CONFIG_OF_CONTROL) += simple-bus.o endif diff --git a/drivers/core/device-remove.c b/drivers/core/device-remove.c index 45d6543..bd6d406 100644 --- a/drivers/core/device-remove.c +++ b/drivers/core/device-remove.c @@ -95,6 +95,9 @@ int device_unbind(struct udevice *dev) if (dev->parent) list_del(&dev->sibling_node); + + devres_release_all(dev); + free(dev); return 0; @@ -128,6 +131,8 @@ void device_free(struct udevice *dev) dev->parent_priv = NULL; } } + + devres_release_probe(dev); } int device_remove(struct udevice *dev) diff --git a/drivers/core/device.c b/drivers/core/device.c index bf6f271..e3a42dc 100644 --- a/drivers/core/device.c +++ b/drivers/core/device.c @@ -47,6 +47,7 @@ int device_bind(struct udevice *parent, const struct driver *drv, INIT_LIST_HEAD(&dev->sibling_node); INIT_LIST_HEAD(&dev->child_head); INIT_LIST_HEAD(&dev->uclass_node); + INIT_LIST_HEAD(&dev->devres_head); dev->platdata = platdata; dev->name = name; dev->of_offset = of_offset; @@ -170,6 +171,8 @@ fail_alloc2: dev->platdata = NULL; } fail_alloc1: + devres_release_all(dev); + free(dev); return ret; diff --git a/drivers/core/devres.c b/drivers/core/devres.c new file mode 100644 index 0000000..49c270c --- /dev/null +++ b/drivers/core/devres.c @@ -0,0 +1,196 @@ +/* + * Copyright (C) 2015 Masahiro Yamada + * + * Based on the original work in Linux by + * Copyright (c) 2006 SUSE Linux Products GmbH + * Copyright (c) 2006 Tejun Heo + * + * SPDX-License-Identifier: GPL-2.0+ + */ + +#include +#include +#include +#include +#include + +/** + * struct devres - Bookkeeping info for managed device resource + * @entry: List to associate this structure with a device + * @release: Callback invoked when this resource is released + * @probe: Flag to show when this resource was allocated + (true = probe, false = bind) + * @name: Name of release function + * @size: Size of resource data + * @data: Resource data + */ +struct devres { + struct list_head entry; + dr_release_t release; + bool probe; +#ifdef CONFIG_DEBUG_DEVRES + const char *name; + size_t size; +#endif + unsigned long long data[]; +}; + +#ifdef CONFIG_DEBUG_DEVRES +static void set_node_dbginfo(struct devres *dr, const char *name, size_t size) +{ + dr->name = name; + dr->size = size; +} + +static void devres_log(struct udevice *dev, struct devres *dr, + const char *op) +{ + printf("%s: DEVRES %3s %p %s (%lu bytes)\n", + dev->name, op, dr, dr->name, (unsigned long)dr->size); +} +#else /* CONFIG_DEBUG_DEVRES */ +#define set_node_dbginfo(dr, n, s) do {} while (0) +#define devres_log(dev, dr, op) do {} while (0) +#endif + +#if CONFIG_DEBUG_DEVRES +void *__devres_alloc(dr_release_t release, size_t size, gfp_t gfp, + const char *name) +#else +void *_devres_alloc(dr_release_t release, size_t size, gfp_t gfp) +#endif +{ + size_t tot_size = sizeof(struct devres) + size; + struct devres *dr; + + dr = kmalloc(tot_size, gfp); + if (unlikely(!dr)) + return NULL; + + INIT_LIST_HEAD(&dr->entry); + dr->release = release; + set_node_dbginfo(dr, name, size); + + return dr->data; +} + +void devres_free(void *res) +{ + if (res) { + struct devres *dr = container_of(res, struct devres, data); + + BUG_ON(!list_empty(&dr->entry)); + kfree(dr); + } +} + +void devres_add(struct udevice *dev, void *res) +{ + struct devres *dr = container_of(res, struct devres, data); + + devres_log(dev, dr, "ADD"); + BUG_ON(!list_empty(&dr->entry)); + dr->probe = dev->flags & DM_FLAG_BOUND ? true : false; + list_add_tail(&dr->entry, &dev->devres_head); +} + +void *devres_find(struct udevice *dev, dr_release_t release, + dr_match_t match, void *match_data) +{ + struct devres *dr; + + list_for_each_entry_reverse(dr, &dev->devres_head, entry) { + if (dr->release != release) + continue; + if (match && !match(dev, dr->data, match_data)) + continue; + return dr->data; + } + + return NULL; +} + +void *devres_get(struct udevice *dev, void *new_res, + dr_match_t match, void *match_data) +{ + struct devres *new_dr = container_of(new_res, struct devres, data); + void *res; + + res = devres_find(dev, new_dr->release, match, match_data); + if (!res) { + devres_add(dev, new_res); + res = new_res; + new_res = NULL; + } + devres_free(new_res); + + return res; +} + +void *devres_remove(struct udevice *dev, dr_release_t release, + dr_match_t match, void *match_data) +{ + void *res; + + res = devres_find(dev, release, match, match_data); + if (res) { + struct devres *dr = container_of(res, struct devres, data); + + list_del_init(&dr->entry); + devres_log(dev, dr, "REM"); + } + + return res; +} + +int devres_destroy(struct udevice *dev, dr_release_t release, + dr_match_t match, void *match_data) +{ + void *res; + + res = devres_remove(dev, release, match, match_data); + if (unlikely(!res)) + return -ENOENT; + + devres_free(res); + return 0; +} + +int devres_release(struct udevice *dev, dr_release_t release, + dr_match_t match, void *match_data) +{ + void *res; + + res = devres_remove(dev, release, match, match_data); + if (unlikely(!res)) + return -ENOENT; + + (*release)(dev, res); + devres_free(res); + return 0; +} + +static void release_nodes(struct udevice *dev, struct list_head *head, + bool probe_only) +{ + struct devres *dr, *tmp; + + list_for_each_entry_safe_reverse(dr, tmp, head, entry) { + if (probe_only && !dr->probe) + break; + devres_log(dev, dr, "REL"); + dr->release(dev, dr->data); + list_del(&dr->entry); + kfree(dr); + } +} + +void devres_release_probe(struct udevice *dev) +{ + release_nodes(dev, &dev->devres_head, true); +} + +void devres_release_all(struct udevice *dev) +{ + release_nodes(dev, &dev->devres_head, false); +} -- cgit v1.1