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473 lines
15 KiB
473 lines
15 KiB
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* Copyright (c) 2016, NVIDIA CORPORATION.
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*/
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#ifndef _RESET_H
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#define _RESET_H
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#include <dm/ofnode.h>
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#include <linux/err.h>
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/**
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* A reset is a hardware signal indicating that a HW module (or IP block, or
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* sometimes an entire off-CPU chip) reset all of its internal state to some
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* known-good initial state. Drivers will often reset HW modules when they
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* begin execution to ensure that hardware correctly responds to all requests,
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* or in response to some error condition. Reset signals are often controlled
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* externally to the HW module being reset, by an entity this API calls a reset
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* controller. This API provides a standard means for drivers to request that
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* reset controllers set or clear reset signals.
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*
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* A driver that implements UCLASS_RESET is a reset controller or provider. A
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* controller will often implement multiple separate reset signals, since the
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* hardware it manages often has this capability. reset-uclass.h describes the
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* interface which reset controllers must implement.
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*
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* Reset consumers/clients are the HW modules affected by reset signals. This
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* header file describes the API used by drivers for those HW modules.
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*/
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struct udevice;
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/**
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* struct reset_ctl - A handle to (allowing control of) a single reset signal.
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*
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* Clients provide storage for reset control handles. The content of the
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* structure is managed solely by the reset API and reset drivers. A reset
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* control struct is initialized by "get"ing the reset control struct. The
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* reset control struct is passed to all other reset APIs to identify which
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* reset signal to operate upon.
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*
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* @dev: The device which implements the reset signal.
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* @id: The reset signal ID within the provider.
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* @data: An optional data field for scenarios where a single integer ID is not
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* sufficient. If used, it can be populated through an .of_xlate op and
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* processed during the various reset ops.
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* @polarity: An optional polarity field for drivers that support
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* different reset polarities.
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*
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* Should additional information to identify and configure any reset signal
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* for any provider be required in the future, the struct could be expanded to
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* either (a) add more fields to allow reset providers to store additional
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* information, or (b) replace the id field with an opaque pointer, which the
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* provider would dynamically allocated during its .of_xlate op, and process
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* during is .request op. This may require the addition of an extra op to clean
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* up the allocation.
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*/
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struct reset_ctl {
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struct udevice *dev;
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/*
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* Written by of_xlate. In the future, we might add more fields here.
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*/
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unsigned long id;
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unsigned long data;
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unsigned long polarity;
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};
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/**
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* struct reset_ctl_bulk - A handle to (allowing control of) a bulk of reset
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* signals.
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*
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* Clients provide storage for the reset control bulk. The content of the
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* structure is managed solely by the reset API. A reset control bulk struct is
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* initialized by "get"ing the reset control bulk struct.
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* The reset control bulk struct is passed to all other bulk reset APIs to apply
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* the API to all the reset signals in the bulk struct.
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*
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* @resets: An array of reset signal handles handles.
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* @count: The number of reset signal handles in the reset array.
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*/
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struct reset_ctl_bulk {
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struct reset_ctl *resets;
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unsigned int count;
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};
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#if CONFIG_IS_ENABLED(DM_RESET)
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/**
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* devm_reset_control_get - resource managed reset_get_by_name()
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* @dev: device to be reset by the controller
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* @id: reset line name
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*
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* Managed reset_get_by_name(). For reset controllers returned
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* from this function, reset_free() is called automatically on driver
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* detach.
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*
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* Returns a struct reset_ctl or IS_ERR() condition containing errno.
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*/
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struct reset_ctl *devm_reset_control_get(struct udevice *dev, const char *id);
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/**
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* devm_reset_control_get_optional - resource managed reset_get_by_name() that
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* can fail
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* @dev: The client device.
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* @id: reset line name
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*
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* Managed reset_get_by_name(). For reset controllers returned
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* from this function, reset_free() is called automatically on driver
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* detach.
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*
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* Returns a struct reset_ctl or a dummy reset controller if it failed.
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*/
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struct reset_ctl *devm_reset_control_get_optional(struct udevice *dev,
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const char *id);
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/**
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* devm_reset_control_get - resource managed reset_get_by_index()
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* @dev: The client device.
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* @index: The index of the reset signal to request, within the client's
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* list of reset signals.
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*
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* Managed reset_get_by_index(). For reset controllers returned
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* from this function, reset_free() is called automatically on driver
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* detach.
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*
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* Returns a struct reset_ctl or IS_ERR() condition containing errno.
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*/
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struct reset_ctl *devm_reset_control_get_by_index(struct udevice *dev,
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int index);
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/**
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* devm_reset_bulk_get - resource managed reset_get_bulk()
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* @dev: device to be reset by the controller
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*
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* Managed reset_get_bulk(). For reset controllers returned
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* from this function, reset_free() is called automatically on driver
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* detach.
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*
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* Returns a struct reset_ctl or IS_ERR() condition containing errno.
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*/
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struct reset_ctl_bulk *devm_reset_bulk_get(struct udevice *dev);
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/**
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* devm_reset_bulk_get_optional - resource managed reset_get_bulk() that
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* can fail
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* @dev: The client device.
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*
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* Managed reset_get_bulk(). For reset controllers returned
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* from this function, reset_free() is called automatically on driver
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* detach.
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*
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* Returns a struct reset_ctl or NULL if it failed.
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*/
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struct reset_ctl_bulk *devm_reset_bulk_get_optional(struct udevice *dev);
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/**
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* devm_reset_bulk_get_by_node - resource managed reset_get_bulk()
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* @dev: device to be reset by the controller
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* @node: ofnode where the "resets" property is. Usually a sub-node of
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* the dev's node.
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*
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* see devm_reset_bulk_get()
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*/
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struct reset_ctl_bulk *devm_reset_bulk_get_by_node(struct udevice *dev,
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ofnode node);
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/**
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* devm_reset_bulk_get_optional_by_node - resource managed reset_get_bulk()
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* that can fail
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* @dev: device to be reset by the controller
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* @node: ofnode where the "resets" property is. Usually a sub-node of
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* the dev's node.
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*
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* see devm_reset_bulk_get_optional()
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*/
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struct reset_ctl_bulk *devm_reset_bulk_get_optional_by_node(struct udevice *dev,
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ofnode node);
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/**
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* reset_get_by_index - Get/request a reset signal by integer index.
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*
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* This looks up and requests a reset signal. The index is relative to the
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* client device; each device is assumed to have n reset signals associated
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* with it somehow, and this function finds and requests one of them. The
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* mapping of client device reset signal indices to provider reset signals may
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* be via device-tree properties, board-provided mapping tables, or some other
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* mechanism.
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*
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* @dev: The client device.
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* @index: The index of the reset signal to request, within the client's
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* list of reset signals.
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* @reset_ctl A pointer to a reset control struct to initialize.
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* Return: 0 if OK, or a negative error code.
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*/
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int reset_get_by_index(struct udevice *dev, int index,
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struct reset_ctl *reset_ctl);
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/**
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* reset_get_by_index_nodev - Get/request a reset signal by integer index
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* without a device.
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*
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* This is a version of reset_get_by_index() that does not use a device.
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*
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* @node: The client ofnode.
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* @index: The index of the reset signal to request, within the client's
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* list of reset signals.
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* @reset_ctl A pointer to a reset control struct to initialize.
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* Return: 0 if OK, or a negative error code.
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*/
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int reset_get_by_index_nodev(ofnode node, int index,
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struct reset_ctl *reset_ctl);
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/**
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* reset_get_bulk - Get/request all reset signals of a device.
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*
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* This looks up and requests all reset signals of the client device; each
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* device is assumed to have n reset signals associated with it somehow,
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* and this function finds and requests all of them in a separate structure.
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* The mapping of client device reset signals indices to provider reset signals
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* may be via device-tree properties, board-provided mapping tables, or some
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* other mechanism.
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*
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* @dev: The client device.
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* @bulk A pointer to a reset control bulk struct to initialize.
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* Return: 0 if OK, or a negative error code.
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*/
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int reset_get_bulk(struct udevice *dev, struct reset_ctl_bulk *bulk);
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/**
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* reset_get_by_name - Get/request a reset signal by name.
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*
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* This looks up and requests a reset signal. The name is relative to the
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* client device; each device is assumed to have n reset signals associated
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* with it somehow, and this function finds and requests one of them. The
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* mapping of client device reset signal names to provider reset signal may be
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* via device-tree properties, board-provided mapping tables, or some other
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* mechanism.
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*
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* @dev: The client device.
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* @name: The name of the reset signal to request, within the client's
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* list of reset signals.
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* @reset_ctl: A pointer to a reset control struct to initialize.
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* Return: 0 if OK, or a negative error code.
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*/
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int reset_get_by_name(struct udevice *dev, const char *name,
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struct reset_ctl *reset_ctl);
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/**
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* reset_request - Request a reset signal.
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*
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* @reset_ctl: A reset control struct.
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*
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* Return: 0 if OK, or a negative error code.
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*/
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int reset_request(struct reset_ctl *reset_ctl);
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/**
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* reset_free - Free a previously requested reset signal.
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*
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* @reset_ctl: A reset control struct that was previously successfully
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* requested by reset_get_by_*().
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* Return: 0 if OK, or a negative error code.
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*/
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int reset_free(struct reset_ctl *reset_ctl);
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/**
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* reset_assert - Assert a reset signal.
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*
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* This function will assert the specified reset signal, thus resetting the
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* affected HW module(s). Depending on the reset controller hardware, the reset
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* signal will either stay asserted until reset_deassert() is called, or the
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* hardware may autonomously clear the reset signal itself.
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*
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* @reset_ctl: A reset control struct that was previously successfully
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* requested by reset_get_by_*().
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* Return: 0 if OK, or a negative error code.
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*/
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int reset_assert(struct reset_ctl *reset_ctl);
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/**
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* reset_assert_bulk - Assert all reset signals in a reset control bulk struct.
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*
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* This function will assert the specified reset signals in a reset control
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* bulk struct, thus resetting the affected HW module(s). Depending on the
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* reset controller hardware, the reset signals will either stay asserted
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* until reset_deassert_bulk() is called, or the hardware may autonomously
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* clear the reset signals itself.
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*
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* @bulk: A reset control bulk struct that was previously successfully
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* requested by reset_get_bulk().
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* Return: 0 if OK, or a negative error code.
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*/
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int reset_assert_bulk(struct reset_ctl_bulk *bulk);
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/**
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* reset_deassert - Deassert a reset signal.
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*
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* This function will deassert the specified reset signal, thus releasing the
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* affected HW modules() from reset, and allowing them to continue normal
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* operation.
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*
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* @reset_ctl: A reset control struct that was previously successfully
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* requested by reset_get_by_*().
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* Return: 0 if OK, or a negative error code.
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*/
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int reset_deassert(struct reset_ctl *reset_ctl);
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/**
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* reset_deassert_bulk - Deassert all reset signals in a reset control bulk
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* struct.
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*
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* This function will deassert the specified reset signals in a reset control
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* bulk struct, thus releasing the affected HW modules() from reset, and
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* allowing them to continue normal operation.
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*
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* @bulk: A reset control bulk struct that was previously successfully
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* requested by reset_get_bulk().
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* Return: 0 if OK, or a negative error code.
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*/
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int reset_deassert_bulk(struct reset_ctl_bulk *bulk);
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/**
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* rst_status - Check reset signal status.
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*
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* @reset_ctl: The reset signal to check.
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* Return: 0 if deasserted, positive if asserted, or a negative
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* error code.
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*/
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int reset_status(struct reset_ctl *reset_ctl);
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/**
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* reset_release_all - Assert/Free an array of previously requested resets.
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*
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* For each reset contained in the reset array, this function will check if
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* reset has been previously requested and then will assert and free it.
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*
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* @reset_ctl: A reset struct array that was previously successfully
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* requested by reset_get_by_*().
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* @count Number of reset contained in the array
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* Return: 0 if OK, or a negative error code.
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*/
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int reset_release_all(struct reset_ctl *reset_ctl, int count);
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/**
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* reset_release_bulk - Assert/Free an array of previously requested reset
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* signals in a reset control bulk struct.
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*
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* For each reset contained in the reset control bulk struct, this function
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* will check if reset has been previously requested and then will assert
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* and free it.
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*
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* @bulk: A reset control bulk struct that was previously successfully
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* requested by reset_get_bulk().
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* Return: 0 if OK, or a negative error code.
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*/
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static inline int reset_release_bulk(struct reset_ctl_bulk *bulk)
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{
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return reset_release_all(bulk->resets, bulk->count);
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}
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#else
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static inline struct reset_ctl *devm_reset_control_get(struct udevice *dev,
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const char *id)
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{
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return ERR_PTR(-ENOTSUPP);
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}
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static inline struct reset_ctl *devm_reset_control_get_optional(struct udevice *dev,
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const char *id)
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{
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return NULL;
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}
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static inline struct reset_ctl *devm_reset_control_get_by_index(struct udevice *dev,
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int index)
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{
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return ERR_PTR(-ENOTSUPP);
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}
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static inline struct reset_ctl_bulk *devm_reset_bulk_get(struct udevice *dev)
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{
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return ERR_PTR(-ENOTSUPP);
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}
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static inline struct reset_ctl_bulk *devm_reset_bulk_get_optional(struct udevice *dev)
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{
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return NULL;
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}
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static inline struct reset_ctl_bulk *devm_reset_bulk_get_by_node(struct udevice *dev,
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ofnode node)
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{
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return ERR_PTR(-ENOTSUPP);
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}
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static inline struct reset_ctl_bulk *devm_reset_bulk_get_optional_by_node(struct udevice *dev,
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ofnode node)
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{
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return NULL;
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}
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static inline int reset_get_by_index(struct udevice *dev, int index,
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struct reset_ctl *reset_ctl)
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{
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return -ENOTSUPP;
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}
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static inline int reset_get_bulk(struct udevice *dev,
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struct reset_ctl_bulk *bulk)
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{
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return -ENOTSUPP;
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}
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static inline int reset_get_by_name(struct udevice *dev, const char *name,
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struct reset_ctl *reset_ctl)
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{
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return -ENOTSUPP;
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}
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static inline int reset_free(struct reset_ctl *reset_ctl)
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{
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return 0;
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}
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static inline int reset_assert(struct reset_ctl *reset_ctl)
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{
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return 0;
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}
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static inline int reset_assert_bulk(struct reset_ctl_bulk *bulk)
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{
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return 0;
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}
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static inline int reset_deassert(struct reset_ctl *reset_ctl)
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{
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return 0;
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}
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static inline int reset_deassert_bulk(struct reset_ctl_bulk *bulk)
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{
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return 0;
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}
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static inline int reset_status(struct reset_ctl *reset_ctl)
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{
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return -ENOTSUPP;
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}
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static inline int reset_release_all(struct reset_ctl *reset_ctl, int count)
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{
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return 0;
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}
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static inline int reset_release_bulk(struct reset_ctl_bulk *bulk)
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{
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return 0;
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}
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#endif
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/**
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* reset_valid() - check if reset is valid
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*
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* @reset_ctl: the reset to check
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* Return: TRUE if valid, or FALSE
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*/
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static inline bool reset_valid(struct reset_ctl *reset_ctl)
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{
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return !!reset_ctl->dev;
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}
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#endif
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