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It is common for system reset to be available at multiple levels in modern hardware. For example, an SoC may provide a reset option, and a board may provide its own reset for reasons of security or thoroughness. It is useful to be able to model this hardware without hard-coding the behaviour in the SoC or board. Also there is a distinction sometimes between resetting just the CPU (leaving GPIO state alone) and resetting all the PMICs, just cutting power. To achieve this, add a simple system reset uclass. It allows multiple devices to provide reset functionality and provides a way to walk through them, requesting a particular reset type until is it provided. Signed-off-by: Simon Glass <sjg@chromium.org>
63 lines
1.5 KiB
C
63 lines
1.5 KiB
C
/*
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* Copyright (c) 2015 Google, Inc
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* Written by Simon Glass <sjg@chromium.org>
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*
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* SPDX-License-Identifier: GPL-2.0+
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*/
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#ifndef __RESET_H
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#define __RESET_H
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enum reset_t {
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RESET_WARM, /* Reset CPU, keep GPIOs active */
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RESET_COLD, /* Reset CPU and GPIOs */
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RESET_POWER, /* Reset PMIC (remove and restore power) */
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RESET_COUNT,
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};
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struct reset_ops {
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/**
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* request() - request a reset of the given type
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*
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* Note that this function may return before the reset takes effect.
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*
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* @type: Reset type to request
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* @return -EINPROGRESS if the reset has been started and
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* will complete soon, -EPROTONOSUPPORT if not supported
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* by this device, 0 if the reset has already happened
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* (in which case this method will not actually return)
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*/
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int (*request)(struct udevice *dev, enum reset_t type);
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};
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#define reset_get_ops(dev) ((struct reset_ops *)(dev)->driver->ops)
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/**
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* reset_request() - request a reset
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*
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* @type: Reset type to request
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* @return 0 if OK, -EPROTONOSUPPORT if not supported by this device
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*/
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int reset_request(struct udevice *dev, enum reset_t type);
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/**
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* reset_walk() - cause a reset
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*
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* This works through the available reset devices until it finds one that can
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* perform a reset. If the provided reset type is not available, the next one
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* will be tried.
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*
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* If this function fails to reset, it will display a message and halt
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*
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* @type: Reset type to request
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*/
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void reset_walk(enum reset_t type);
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/**
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* reset_cpu() - calls reset_walk(RESET_WARM)
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*/
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void reset_cpu(ulong addr);
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#endif
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