X-Git-Url: https://gerrit.opnfv.org/gerrit/gitweb?a=blobdiff_plain;f=kernel%2Fdrivers%2Freset%2Fcore.c;fp=kernel%2Fdrivers%2Freset%2Fcore.c;h=7955e00d04d49fca9f16d78f1fa50835c038bf46;hb=9ca8dbcc65cfc63d6f5ef3312a33184e1d726e00;hp=0000000000000000000000000000000000000000;hpb=98260f3884f4a202f9ca5eabed40b1354c489b29;p=kvmfornfv.git diff --git a/kernel/drivers/reset/core.c b/kernel/drivers/reset/core.c new file mode 100644 index 000000000..7955e00d0 --- /dev/null +++ b/kernel/drivers/reset/core.c @@ -0,0 +1,305 @@ +/* + * Reset Controller framework + * + * Copyright 2013 Philipp Zabel, Pengutronix + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + */ +#include +#include +#include +#include +#include +#include +#include +#include +#include + +static DEFINE_MUTEX(reset_controller_list_mutex); +static LIST_HEAD(reset_controller_list); + +/** + * struct reset_control - a reset control + * @rcdev: a pointer to the reset controller device + * this reset control belongs to + * @id: ID of the reset controller in the reset + * controller device + */ +struct reset_control { + struct reset_controller_dev *rcdev; + struct device *dev; + unsigned int id; +}; + +/** + * of_reset_simple_xlate - translate reset_spec to the reset line number + * @rcdev: a pointer to the reset controller device + * @reset_spec: reset line specifier as found in the device tree + * @flags: a flags pointer to fill in (optional) + * + * This simple translation function should be used for reset controllers + * with 1:1 mapping, where reset lines can be indexed by number without gaps. + */ +static int of_reset_simple_xlate(struct reset_controller_dev *rcdev, + const struct of_phandle_args *reset_spec) +{ + if (WARN_ON(reset_spec->args_count != rcdev->of_reset_n_cells)) + return -EINVAL; + + if (reset_spec->args[0] >= rcdev->nr_resets) + return -EINVAL; + + return reset_spec->args[0]; +} + +/** + * reset_controller_register - register a reset controller device + * @rcdev: a pointer to the initialized reset controller device + */ +int reset_controller_register(struct reset_controller_dev *rcdev) +{ + if (!rcdev->of_xlate) { + rcdev->of_reset_n_cells = 1; + rcdev->of_xlate = of_reset_simple_xlate; + } + + mutex_lock(&reset_controller_list_mutex); + list_add(&rcdev->list, &reset_controller_list); + mutex_unlock(&reset_controller_list_mutex); + + return 0; +} +EXPORT_SYMBOL_GPL(reset_controller_register); + +/** + * reset_controller_unregister - unregister a reset controller device + * @rcdev: a pointer to the reset controller device + */ +void reset_controller_unregister(struct reset_controller_dev *rcdev) +{ + mutex_lock(&reset_controller_list_mutex); + list_del(&rcdev->list); + mutex_unlock(&reset_controller_list_mutex); +} +EXPORT_SYMBOL_GPL(reset_controller_unregister); + +/** + * reset_control_reset - reset the controlled device + * @rstc: reset controller + */ +int reset_control_reset(struct reset_control *rstc) +{ + if (rstc->rcdev->ops->reset) + return rstc->rcdev->ops->reset(rstc->rcdev, rstc->id); + + return -ENOSYS; +} +EXPORT_SYMBOL_GPL(reset_control_reset); + +/** + * reset_control_assert - asserts the reset line + * @rstc: reset controller + */ +int reset_control_assert(struct reset_control *rstc) +{ + if (rstc->rcdev->ops->assert) + return rstc->rcdev->ops->assert(rstc->rcdev, rstc->id); + + return -ENOSYS; +} +EXPORT_SYMBOL_GPL(reset_control_assert); + +/** + * reset_control_deassert - deasserts the reset line + * @rstc: reset controller + */ +int reset_control_deassert(struct reset_control *rstc) +{ + if (rstc->rcdev->ops->deassert) + return rstc->rcdev->ops->deassert(rstc->rcdev, rstc->id); + + return -ENOSYS; +} +EXPORT_SYMBOL_GPL(reset_control_deassert); + +/** + * reset_control_status - returns a negative errno if not supported, a + * positive value if the reset line is asserted, or zero if the reset + * line is not asserted. + * @rstc: reset controller + */ +int reset_control_status(struct reset_control *rstc) +{ + if (rstc->rcdev->ops->status) + return rstc->rcdev->ops->status(rstc->rcdev, rstc->id); + + return -ENOSYS; +} +EXPORT_SYMBOL_GPL(reset_control_status); + +/** + * of_reset_control_get - Lookup and obtain a reference to a reset controller. + * @node: device to be reset by the controller + * @id: reset line name + * + * Returns a struct reset_control or IS_ERR() condition containing errno. + * + * Use of id names is optional. + */ +struct reset_control *of_reset_control_get(struct device_node *node, + const char *id) +{ + struct reset_control *rstc = ERR_PTR(-EPROBE_DEFER); + struct reset_controller_dev *r, *rcdev; + struct of_phandle_args args; + int index = 0; + int rstc_id; + int ret; + + if (id) + index = of_property_match_string(node, + "reset-names", id); + ret = of_parse_phandle_with_args(node, "resets", "#reset-cells", + index, &args); + if (ret) + return ERR_PTR(ret); + + mutex_lock(&reset_controller_list_mutex); + rcdev = NULL; + list_for_each_entry(r, &reset_controller_list, list) { + if (args.np == r->of_node) { + rcdev = r; + break; + } + } + of_node_put(args.np); + + if (!rcdev) { + mutex_unlock(&reset_controller_list_mutex); + return ERR_PTR(-EPROBE_DEFER); + } + + rstc_id = rcdev->of_xlate(rcdev, &args); + if (rstc_id < 0) { + mutex_unlock(&reset_controller_list_mutex); + return ERR_PTR(rstc_id); + } + + try_module_get(rcdev->owner); + mutex_unlock(&reset_controller_list_mutex); + + rstc = kzalloc(sizeof(*rstc), GFP_KERNEL); + if (!rstc) { + module_put(rcdev->owner); + return ERR_PTR(-ENOMEM); + } + + rstc->rcdev = rcdev; + rstc->id = rstc_id; + + return rstc; +} +EXPORT_SYMBOL_GPL(of_reset_control_get); + +/** + * reset_control_get - Lookup and obtain a reference to a reset controller. + * @dev: device to be reset by the controller + * @id: reset line name + * + * Returns a struct reset_control or IS_ERR() condition containing errno. + * + * Use of id names is optional. + */ +struct reset_control *reset_control_get(struct device *dev, const char *id) +{ + struct reset_control *rstc; + + if (!dev) + return ERR_PTR(-EINVAL); + + rstc = of_reset_control_get(dev->of_node, id); + if (!IS_ERR(rstc)) + rstc->dev = dev; + + return rstc; +} +EXPORT_SYMBOL_GPL(reset_control_get); + +/** + * reset_control_put - free the reset controller + * @rstc: reset controller + */ + +void reset_control_put(struct reset_control *rstc) +{ + if (IS_ERR(rstc)) + return; + + module_put(rstc->rcdev->owner); + kfree(rstc); +} +EXPORT_SYMBOL_GPL(reset_control_put); + +static void devm_reset_control_release(struct device *dev, void *res) +{ + reset_control_put(*(struct reset_control **)res); +} + +/** + * devm_reset_control_get - resource managed reset_control_get() + * @dev: device to be reset by the controller + * @id: reset line name + * + * Managed reset_control_get(). For reset controllers returned from this + * function, reset_control_put() is called automatically on driver detach. + * See reset_control_get() for more information. + */ +struct reset_control *devm_reset_control_get(struct device *dev, const char *id) +{ + struct reset_control **ptr, *rstc; + + ptr = devres_alloc(devm_reset_control_release, sizeof(*ptr), + GFP_KERNEL); + if (!ptr) + return ERR_PTR(-ENOMEM); + + rstc = reset_control_get(dev, id); + if (!IS_ERR(rstc)) { + *ptr = rstc; + devres_add(dev, ptr); + } else { + devres_free(ptr); + } + + return rstc; +} +EXPORT_SYMBOL_GPL(devm_reset_control_get); + +/** + * device_reset - find reset controller associated with the device + * and perform reset + * @dev: device to be reset by the controller + * + * Convenience wrapper for reset_control_get() and reset_control_reset(). + * This is useful for the common case of devices with single, dedicated reset + * lines. + */ +int device_reset(struct device *dev) +{ + struct reset_control *rstc; + int ret; + + rstc = reset_control_get(dev, NULL); + if (IS_ERR(rstc)) + return PTR_ERR(rstc); + + ret = reset_control_reset(rstc); + + reset_control_put(rstc); + + return ret; +} +EXPORT_SYMBOL_GPL(device_reset);