mirror of
https://github.com/brain-hackers/u-boot-brain
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f9917454d5
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
1.1 KiB
C
63 lines
1.1 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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#include <common.h>
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#include <reset.h>
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#include <dm.h>
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#include <errno.h>
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#include <regmap.h>
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#include <dm/device-internal.h>
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#include <dm/lists.h>
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#include <dm/root.h>
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#include <linux/err.h>
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int reset_request(struct udevice *dev, enum reset_t type)
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{
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struct reset_ops *ops = reset_get_ops(dev);
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if (!ops->request)
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return -ENOSYS;
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return ops->request(dev, type);
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}
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void reset_walk(enum reset_t type)
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{
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struct udevice *dev;
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int ret = 0;
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while (ret != -EINPROGRESS && type < RESET_COUNT) {
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for (uclass_first_device(UCLASS_RESET, &dev);
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dev;
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uclass_next_device(&dev)) {
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ret = reset_request(dev, type);
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if (ret == -EINPROGRESS)
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break;
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}
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}
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/* Wait for the reset to take effect */
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mdelay(100);
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/* Still no reset? Give up */
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printf("Reset not supported on this platform\n");
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hang();
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}
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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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{
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reset_walk(RESET_WARM);
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}
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UCLASS_DRIVER(reset) = {
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.id = UCLASS_RESET,
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.name = "reset",
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};
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