1 files changed, 339 insertions, 0 deletions
diff --git a/include/reset.h b/include/reset.h
new file mode 100644
index 0000000..4fac4e6
--- /dev/null
+++ b/include/reset.h
@@ -0,0 +1,339 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2016, NVIDIA CORPORATION.
+ */
+
+#ifndef _RESET_H
+#define _RESET_H
+
+#include <dm/ofnode.h>
+#include <linux/errno.h>
+
+/**
+ * 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 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.
+ * @data: An optional data field for scenarios where a single integer ID is not
+ *	  sufficient. If used, it can be populated through an .of_xlate op and
+ *	  processed during the various reset ops.
+ * @polarity: An optional polarity field for drivers that support
+ *	  different reset polarities.
+ *
+ * Should additional information to identify and configure any reset signal
+ * for any provider be required 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. In the future, we might add more fields here.
+	 */
+	unsigned long id;
+	unsigned long data;
+	unsigned long polarity;
+};
+
+/**
+ * struct reset_ctl_bulk - A handle to (allowing control of) a bulk of reset
+ * signals.
+ *
+ * Clients provide storage for the reset control bulk. The content of the
+ * structure is managed solely by the reset API. A reset control bulk struct is
+ * initialized by "get"ing the reset control bulk struct.
+ * The reset control bulk struct is passed to all other bulk reset APIs to apply
+ * the API to all the reset signals in the bulk struct.
+ *
+ * @resets: An array of reset signal handles handles.
+ * @count: The number of reset signal handles in the reset array.
+ */
+struct reset_ctl_bulk {
+	struct reset_ctl *resets;
+	unsigned int count;
+};
+
+#if CONFIG_IS_ENABLED(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_index_nodev - Get/request a reset signal by integer index
+ * without a device.
+ *
+ * This is a version of reset_get_by_index() that does not use a device.
+ *
+ * @node:	The client ofnode.
+ * @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_nodev(ofnode node, int index,
+			     struct reset_ctl *reset_ctl);
+
+/**
+ * reset_get_bulk - Get/request all reset signals of a device.
+ *
+ * This looks up and requests all reset signals of the client device; each
+ * device is assumed to have n reset signals associated with it somehow,
+ * and this function finds and requests all of them in a separate structure.
+ * The mapping of client device reset signals indices to provider reset signals
+ * may be via device-tree properties, board-provided mapping tables, or some
+ * other mechanism.
+ *
+ * @dev:	The client device.
+ * @bulk	A pointer to a reset control bulk struct to initialize.
+ * @return 0 if OK, or a negative error code.
+ */
+int reset_get_bulk(struct udevice *dev, struct reset_ctl_bulk *bulk);
+
+/**
+ * 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 signal.
+ *
+ * @reset_ctl:	A reset control struct.
+ *
+ * @return 0 if OK, or a negative error code.
+ */
+int reset_request(struct reset_ctl *reset_ctl);
+
+/**
+ * reset_free - Free a previously requested reset signal.
+ *
+ * @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.
+ *
+ * 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.
+ *
+ * @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_assert(struct reset_ctl *reset_ctl);
+
+/**
+ * reset_assert_bulk - Assert all reset signals in a reset control bulk struct.
+ *
+ * This function will assert the specified reset signals in a reset control
+ * bulk struct, thus resetting the affected HW module(s). Depending on the
+ * reset controller hardware, the reset signals will either stay asserted
+ * until reset_deassert_bulk() is called, or the hardware may autonomously
+ * clear the reset signals itself.
+ *
+ * @bulk:	A reset control bulk struct that was previously successfully
+ *		requested by reset_get_bulk().
+ * @return 0 if OK, or a negative error code.
+ */
+int reset_assert_bulk(struct reset_ctl_bulk *bulk);
+
+/**
+ * reset_deassert - Deassert a reset signal.
+ *
+ * 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.
+ */
+int reset_deassert(struct reset_ctl *reset_ctl);
+
+/**
+ * reset_deassert_bulk - Deassert all reset signals in a reset control bulk
+ * struct.
+ *
+ * This function will deassert the specified reset signals in a reset control
+ * bulk struct, thus releasing the affected HW modules() from reset, and
+ * allowing them to continue normal operation.
+ *
+ * @bulk:	A reset control bulk struct that was previously successfully
+ *		requested by reset_get_bulk().
+ * @return 0 if OK, or a negative error code.
+ */
+int reset_deassert_bulk(struct reset_ctl_bulk *bulk);
+
+/**
+ * rst_status - Check reset signal status.
+ *
+ * @reset_ctl:	The reset signal to check.
+ * @return 0 if deasserted, positive if asserted, or a negative
+ *           error code.
+ */
+int reset_status(struct reset_ctl *reset_ctl);
+
+/**
+ * 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.
+ */
+int reset_release_all(struct reset_ctl *reset_ctl, int count);
+
+/**
+ * reset_release_bulk - Assert/Free an array of previously requested reset
+ * signals in a reset control bulk struct.
+ *
+ * For each reset contained in the reset control bulk struct, this function
+ * will check if reset has been previously requested and then will assert
+ * and free it.
+ *
+ * @bulk:	A reset control bulk struct that was previously successfully
+ *		requested by reset_get_bulk().
+ * @return 0 if OK, or a negative error code.
+ */
+static inline int reset_release_bulk(struct reset_ctl_bulk *bulk)
+{
+	return reset_release_all(bulk->resets, bulk->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_bulk(struct udevice *dev,
+				 struct reset_ctl_bulk *bulk)
+{
+	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_assert_bulk(struct reset_ctl_bulk *bulk)
+{
+	return 0;
+}
+
+static inline int reset_deassert(struct reset_ctl *reset_ctl)
+{
+	return 0;
+}
+
+static inline int reset_deassert_bulk(struct reset_ctl_bulk *bulk)
+{
+	return 0;
+}
+
+static inline int reset_status(struct reset_ctl *reset_ctl)
+{
+	return -ENOTSUPP;
+}
+
+static inline int reset_release_all(struct reset_ctl *reset_ctl, int count)
+{
+	return 0;
+}
+
+static inline int reset_release_bulk(struct reset_ctl_bulk *bulk)
+{
+	return 0;
+}
+#endif
+
+/**
+ * reset_valid() - check if reset is valid
+ *
+ * @reset_ctl:		the reset to check
+ * @return TRUE if valid, or FALSE
+ */
+static inline bool reset_valid(struct reset_ctl *reset_ctl)
+{
+	return !!reset_ctl->dev;
+}
+
+#endif