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include/reset.h
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/* * Copyright (c) 2016, NVIDIA CORPORATION. * * SPDX-License-Identifier: GPL-2.0 */ #ifndef _RESET_H #define _RESET_H |
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#include <linux/errno.h> |
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/** * A reset is a hardware signal indicating that a HW module (or IP block, or * sometimes an entire off-CPU chip) reset all of its internal state to some * known-good initial state. Drivers will often reset HW modules when they * begin execution to ensure that hardware correctly responds to all requests, * or in response to some error condition. Reset signals are often controlled * externally to the HW module being reset, by an entity this API calls a reset * controller. This API provides a standard means for drivers to request that * reset controllers set or clear reset signals. * * A driver that implements UCLASS_RESET is a reset controller or provider. A * controller will often implement multiple separate reset signals, since the * hardware it manages often has this capability. reset-uclass.h describes the * interface which reset controllers must implement. * * Reset consumers/clients are the HW modules affected by reset signals. This * header file describes the API used by drivers for those HW modules. */ struct udevice; /** * struct reset_ctl - A handle to (allowing control of) a single reset signal. * * Clients provide storage for reset control handles. The content of the * structure is managed solely by the reset API and reset drivers. A reset * control struct is initialized by "get"ing the reset control struct. The * reset control struct is passed to all other reset APIs to identify which * reset signal to operate upon. * * @dev: The device which implements the reset signal. * @id: The reset signal ID within the provider. * * Currently, the reset API assumes that a single integer ID is enough to * identify and configure any reset signal for any reset provider. If this * assumption becomes invalid in the future, the struct could be expanded to * either (a) add more fields to allow reset providers to store additional * information, or (b) replace the id field with an opaque pointer, which the * provider would dynamically allocated during its .of_xlate op, and process * during is .request op. This may require the addition of an extra op to clean * up the allocation. */ struct reset_ctl { struct udevice *dev; /* * Written by of_xlate. We assume a single id is enough for now. In the * future, we might add more fields here. */ unsigned long id; }; |
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#ifdef CONFIG_DM_RESET |
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/** * reset_get_by_index - Get/request a reset signal by integer index. * * This looks up and requests a reset signal. The index is relative to the * client device; each device is assumed to have n reset signals associated * with it somehow, and this function finds and requests one of them. The * mapping of client device reset signal indices to provider reset signals may * be via device-tree properties, board-provided mapping tables, or some other * mechanism. * * @dev: The client device. * @index: The index of the reset signal to request, within the client's * list of reset signals. * @reset_ctl A pointer to a reset control struct to initialize. * @return 0 if OK, or a negative error code. */ int reset_get_by_index(struct udevice *dev, int index, struct reset_ctl *reset_ctl); /** * reset_get_by_name - Get/request a reset signal by name. * * This looks up and requests a reset signal. The name is relative to the * client device; each device is assumed to have n reset signals associated * with it somehow, and this function finds and requests one of them. The * mapping of client device reset signal names to provider reset signal may be * via device-tree properties, board-provided mapping tables, or some other * mechanism. * * @dev: The client device. * @name: The name of the reset signal to request, within the client's * list of reset signals. * @reset_ctl: A pointer to a reset control struct to initialize. * @return 0 if OK, or a negative error code. */ int reset_get_by_name(struct udevice *dev, const char *name, struct reset_ctl *reset_ctl); /** |
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* reset_request - Request a reset signal. * * @reset_ctl: A reset control struct. * * @return 0 if OK, or a negative error code. */ int reset_request(struct reset_ctl *reset_ctl); /** |
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* reset_free - Free a previously requested reset signal. * * @reset_ctl: A reset control struct that was previously successfully * requested by reset_get_by_*(). * @return 0 if OK, or a negative error code. */ int reset_free(struct reset_ctl *reset_ctl); /** * reset_assert - Assert a reset signal. * * This function will assert the specified reset signal, thus resetting the * affected HW module(s). Depending on the reset controller hardware, the reset * signal will either stay asserted until reset_deassert() is called, or the * hardware may autonomously clear the reset signal itself. * * @reset_ctl: A reset control struct that was previously successfully * requested by reset_get_by_*(). * @return 0 if OK, or a negative error code. */ int reset_assert(struct reset_ctl *reset_ctl); /** * reset_deassert - Deassert a reset signal. * * This function will deassert the specified reset signal, thus releasing the * affected HW modules() from reset, and allowing them to continue normal * operation. * * @reset_ctl: A reset control struct that was previously successfully * requested by reset_get_by_*(). * @return 0 if OK, or a negative error code. */ int reset_deassert(struct reset_ctl *reset_ctl); |
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/** * reset_release_all - Assert/Free an array of previously requested resets. * * For each reset contained in the reset array, this function will check if * reset has been previously requested and then will assert and free it. * * @reset_ctl: A reset struct array that was previously successfully * requested by reset_get_by_*(). * @count Number of reset contained in the array * @return 0 if OK, or a negative error code. */ int reset_release_all(struct reset_ctl *reset_ctl, int count); |
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#else static inline int reset_get_by_index(struct udevice *dev, int index, struct reset_ctl *reset_ctl) { return -ENOTSUPP; } static inline int reset_get_by_name(struct udevice *dev, const char *name, struct reset_ctl *reset_ctl) { return -ENOTSUPP; } static inline int reset_free(struct reset_ctl *reset_ctl) { return 0; } static inline int reset_assert(struct reset_ctl *reset_ctl) { return 0; } static inline int reset_deassert(struct reset_ctl *reset_ctl) { return 0; } |
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static inline int reset_release_all(struct reset_ctl *reset_ctl, int count) { return 0; } |
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#endif |
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#endif |