/*
- * Copyright (c) 2015 Google, Inc
- * Written by Simon Glass <sjg@chromium.org>
+ * Copyright (c) 2016, NVIDIA CORPORATION.
*
- * SPDX-License-Identifier: GPL-2.0+
+ * SPDX-License-Identifier: GPL-2.0
*/
-#ifndef __RESET_H
-#define __RESET_H
+#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) */
+#include <linux/errno.h>
- RESET_COUNT,
-};
+/**
+ * A reset is a hardware signal indicating that a HW module (or IP block, or
+ * sometimes an entire off-CPU chip) reset all of its internal state to some
+ * known-good initial state. Drivers will often reset HW modules when they
+ * begin execution to ensure that hardware correctly responds to all requests,
+ * or in response to some error condition. Reset signals are often controlled
+ * externally to the HW module being reset, by an entity this API calls a reset
+ * controller. This API provides a standard means for drivers to request that
+ * reset controllers set or clear reset signals.
+ *
+ * A driver that implements UCLASS_RESET is a reset controller or provider. A
+ * controller will often implement multiple separate reset signals, since the
+ * hardware it manages often has this capability. reset-uclass.h describes the
+ * interface which reset controllers must implement.
+ *
+ * Reset consumers/clients are the HW modules affected by reset signals. This
+ * header file describes the API used by drivers for those HW modules.
+ */
-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)
+struct udevice;
+
+/**
+ * struct reset_ctl - A handle to (allowing control of) a single reset signal.
+ *
+ * Clients provide storage for reset control handles. The content of the
+ * structure is managed solely by the reset API and reset drivers. A reset
+ * control struct is initialized by "get"ing the reset control struct. The
+ * reset control struct is passed to all other reset APIs to identify which
+ * reset signal to operate upon.
+ *
+ * @dev: The device which implements the reset signal.
+ * @id: The reset signal ID within the provider.
+ *
+ * Currently, the reset API assumes that a single integer ID is enough to
+ * identify and configure any reset signal for any reset provider. If this
+ * assumption becomes invalid in the future, the struct could be expanded to
+ * either (a) add more fields to allow reset providers to store additional
+ * information, or (b) replace the id field with an opaque pointer, which the
+ * provider would dynamically allocated during its .of_xlate op, and process
+ * during is .request op. This may require the addition of an extra op to clean
+ * up the allocation.
+ */
+struct reset_ctl {
+ struct udevice *dev;
+ /*
+ * Written by of_xlate. We assume a single id is enough for now. In the
+ * future, we might add more fields here.
*/
- int (*request)(struct udevice *dev, enum reset_t type);
+ unsigned long id;
};
-#define reset_get_ops(dev) ((struct reset_ops *)(dev)->driver->ops)
+#ifdef CONFIG_DM_RESET
+/**
+ * reset_get_by_index - Get/request a reset signal by integer index.
+ *
+ * This looks up and requests a reset signal. The index is relative to the
+ * client device; each device is assumed to have n reset signals associated
+ * with it somehow, and this function finds and requests one of them. The
+ * mapping of client device reset signal indices to provider reset signals may
+ * be via device-tree properties, board-provided mapping tables, or some other
+ * mechanism.
+ *
+ * @dev: The client device.
+ * @index: The index of the reset signal to request, within the client's
+ * list of reset signals.
+ * @reset_ctl A pointer to a reset control struct to initialize.
+ * @return 0 if OK, or a negative error code.
+ */
+int reset_get_by_index(struct udevice *dev, int index,
+ struct reset_ctl *reset_ctl);
+
+/**
+ * reset_get_by_name - Get/request a reset signal by name.
+ *
+ * This looks up and requests a reset signal. The name is relative to the
+ * client device; each device is assumed to have n reset signals associated
+ * with it somehow, and this function finds and requests one of them. The
+ * mapping of client device reset signal names to provider reset signal may be
+ * via device-tree properties, board-provided mapping tables, or some other
+ * mechanism.
+ *
+ * @dev: The client device.
+ * @name: The name of the reset signal to request, within the client's
+ * list of reset signals.
+ * @reset_ctl: A pointer to a reset control struct to initialize.
+ * @return 0 if OK, or a negative error code.
+ */
+int reset_get_by_name(struct udevice *dev, const char *name,
+ struct reset_ctl *reset_ctl);
/**
- * reset_request() - request a reset
+ * reset_request - Request a reset signal.
*
- * @type: Reset type to request
- * @return 0 if OK, -EPROTONOSUPPORT if not supported by this device
+ * @reset_ctl: A reset control struct.
+ *
+ * @return 0 if OK, or a negative error code.
*/
-int reset_request(struct udevice *dev, enum reset_t type);
+int reset_request(struct reset_ctl *reset_ctl);
/**
- * reset_walk() - cause a reset
+ * reset_free - Free a previously requested reset signal.
*
- * 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.
+ * @reset_ctl: A reset control struct that was previously successfully
+ * requested by reset_get_by_*().
+ * @return 0 if OK, or a negative error code.
+ */
+int reset_free(struct reset_ctl *reset_ctl);
+
+/**
+ * reset_assert - Assert a reset signal.
*
- * If this function fails to reset, it will display a message and halt
+ * This function will assert the specified reset signal, thus resetting the
+ * affected HW module(s). Depending on the reset controller hardware, the reset
+ * signal will either stay asserted until reset_deassert() is called, or the
+ * hardware may autonomously clear the reset signal itself.
*
- * @type: Reset type to request
- * @return -EINPROGRESS if a reset is in progress, -ENOSYS if not available
+ * @reset_ctl: A reset control struct that was previously successfully
+ * requested by reset_get_by_*().
+ * @return 0 if OK, or a negative error code.
*/
-int reset_walk(enum reset_t type);
+int reset_assert(struct reset_ctl *reset_ctl);
/**
- * reset_walk_halt() - try to reset, otherwise halt
+ * reset_deassert - Deassert a reset signal.
*
- * This calls reset_walk(). If it returns, indicating that reset is not
- * supported, it prints a message and halts.
+ * This function will deassert the specified reset signal, thus releasing the
+ * affected HW modules() from reset, and allowing them to continue normal
+ * operation.
+ *
+ * @reset_ctl: A reset control struct that was previously successfully
+ * requested by reset_get_by_*().
+ * @return 0 if OK, or a negative error code.
*/
-void reset_walk_halt(enum reset_t type);
+int reset_deassert(struct reset_ctl *reset_ctl);
/**
- * reset_cpu() - calls reset_walk(RESET_WARM)
+ * reset_release_all - Assert/Free an array of previously requested resets.
+ *
+ * For each reset contained in the reset array, this function will check if
+ * reset has been previously requested and then will assert and free it.
+ *
+ * @reset_ctl: A reset struct array that was previously successfully
+ * requested by reset_get_by_*().
+ * @count Number of reset contained in the array
+ * @return 0 if OK, or a negative error code.
*/
-void reset_cpu(ulong addr);
+int reset_release_all(struct reset_ctl *reset_ctl, int count);
+#else
+static inline int reset_get_by_index(struct udevice *dev, int index,
+ struct reset_ctl *reset_ctl)
+{
+ return -ENOTSUPP;
+}
+
+static inline int reset_get_by_name(struct udevice *dev, const char *name,
+ struct reset_ctl *reset_ctl)
+{
+ return -ENOTSUPP;
+}
+
+static inline int reset_free(struct reset_ctl *reset_ctl)
+{
+ return 0;
+}
+
+static inline int reset_assert(struct reset_ctl *reset_ctl)
+{
+ return 0;
+}
+
+static inline int reset_deassert(struct reset_ctl *reset_ctl)
+{
+ return 0;
+}
+
+static inline int reset_release_all(struct reset_ctl *reset_ctl, int count)
+{
+ return 0;
+}
+
+#endif
#endif
projects / people / ms / u-boot.git / blobdiff