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authorSimon Glass <sjg@chromium.org>2015-06-23 15:39:13 -0600
committerSimon Glass <sjg@chromium.org>2015-07-21 17:39:29 -0600
commitf9917454d55caf3dafa41b27d8d8274716433a4c (patch)
tree81f7c0e4cb2a9c3e04eab94ef17da21f2de1192f /include/reset.h
parent92a655c326b22de58dcd5371ca1a62fdc57f8e04 (diff)
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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 <sjg@chromium.org>
Diffstat (limited to 'include/reset.h')
-rw-r--r--include/reset.h62
1 files changed, 62 insertions, 0 deletions
diff --git a/include/reset.h b/include/reset.h
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index 0000000000..d29e108eec
--- /dev/null
+++ b/include/reset.h
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+/*
+ * Copyright (c) 2015 Google, Inc
+ * Written by Simon Glass <sjg@chromium.org>
+ *
+ * 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
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