From f9917454d55caf3dafa41b27d8d8274716433a4c Mon Sep 17 00:00:00 2001 From: Simon Glass Date: Tue, 23 Jun 2015 15:39:13 -0600 Subject: dm: Add a system reset uclass 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 --- include/reset.h | 62 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 62 insertions(+) create mode 100644 include/reset.h (limited to 'include/reset.h') diff --git a/include/reset.h b/include/reset.h new file mode 100644 index 0000000000..d29e108eec --- /dev/null +++ b/include/reset.h @@ -0,0 +1,62 @@ +/* + * Copyright (c) 2015 Google, Inc + * Written by Simon Glass + * + * SPDX-License-Identifier: GPL-2.0+ + */ + +#ifndef __RESET_H +#define __RESET_H + +enum reset_t { + RESET_WARM, /* Reset CPU, keep GPIOs active */ + RESET_COLD, /* Reset CPU and GPIOs */ + RESET_POWER, /* Reset PMIC (remove and restore power) */ + + RESET_COUNT, +}; + +struct reset_ops { + /** + * request() - request a reset of the given type + * + * Note that this function may return before the reset takes effect. + * + * @type: Reset type to request + * @return -EINPROGRESS if the reset has been started and + * will complete soon, -EPROTONOSUPPORT if not supported + * by this device, 0 if the reset has already happened + * (in which case this method will not actually return) + */ + int (*request)(struct udevice *dev, enum reset_t type); +}; + +#define reset_get_ops(dev) ((struct reset_ops *)(dev)->driver->ops) + +/** + * reset_request() - request a reset + * + * @type: Reset type to request + * @return 0 if OK, -EPROTONOSUPPORT if not supported by this device + */ +int reset_request(struct udevice *dev, enum reset_t type); + +/** + * reset_walk() - cause a reset + * + * This works through the available reset devices until it finds one that can + * perform a reset. If the provided reset type is not available, the next one + * will be tried. + * + * If this function fails to reset, it will display a message and halt + * + * @type: Reset type to request + */ +void reset_walk(enum reset_t type); + +/** + * reset_cpu() - calls reset_walk(RESET_WARM) + */ +void reset_cpu(ulong addr); + +#endif -- cgit v1.2.1