1 // SPDX-License-Identifier: GPL-2.0+
3 * Texas Instruments System Control Interface (TI SCI) reset driver
5 * Copyright (C) 2018 Texas Instruments Incorporated - http://www.ti.com/
6 * Andreas Dannenberg <dannenberg@ti.com>
8 * Loosely based on Linux kernel reset-ti-sci.c...
15 #include <reset-uclass.h>
16 #include <dm/device_compat.h>
17 #include <linux/err.h>
18 #include <linux/soc/ti/ti_sci_protocol.h>
21 * struct ti_sci_reset_data - reset controller information structure
22 * @sci: TI SCI handle used for communication with system controller
24 struct ti_sci_reset_data {
25 const struct ti_sci_handle *sci;
28 static int ti_sci_reset_probe(struct udevice *dev)
30 struct ti_sci_reset_data *data = dev_get_priv(dev);
32 debug("%s(dev=%p)\n", __func__, dev);
37 /* Store handle for communication with the system controller */
38 data->sci = ti_sci_get_handle(dev);
39 if (IS_ERR(data->sci))
40 return PTR_ERR(data->sci);
45 static int ti_sci_reset_of_xlate(struct reset_ctl *rst,
46 struct ofnode_phandle_args *args)
48 debug("%s(rst=%p, args_count=%d)\n", __func__, rst, args->args_count);
50 if (args->args_count != 2) {
51 debug("Invalid args_count: %d\n", args->args_count);
56 * On TI SCI-based devices, the reset provider id field is used as a
57 * device ID, and the data field is used as the associated reset mask.
59 rst->id = args->args[0];
60 rst->data = args->args[1];
65 static int ti_sci_reset_request(struct reset_ctl *rst)
67 debug("%s(rst=%p)\n", __func__, rst);
71 static int ti_sci_reset_free(struct reset_ctl *rst)
73 debug("%s(rst=%p)\n", __func__, rst);
78 * ti_sci_reset_set() - program a device's reset
79 * @rst: Handle to a single reset signal
80 * @assert: boolean flag to indicate assert or deassert
82 * This is a common internal function used to assert or deassert a device's
83 * reset using the TI SCI protocol. The device's reset is asserted if the
84 * @assert argument is true, or deasserted if @assert argument is false.
85 * The mechanism itself is a read-modify-write procedure, the current device
86 * reset register is read using a TI SCI device operation, the new value is
87 * set or un-set using the reset's mask, and the new reset value written by
88 * using another TI SCI device operation.
90 * Return: 0 for successful request, else a corresponding error value
92 static int ti_sci_reset_set(struct reset_ctl *rst, bool assert)
94 struct ti_sci_reset_data *data = dev_get_priv(rst->dev);
95 const struct ti_sci_handle *sci = data->sci;
96 const struct ti_sci_dev_ops *dops = &sci->ops.dev_ops;
100 ret = dops->get_device_resets(sci, rst->id, &reset_state);
102 dev_err(rst->dev, "%s: get_device_resets failed (%d)\n",
108 reset_state |= rst->data;
110 reset_state &= ~rst->data;
112 ret = dops->set_device_resets(sci, rst->id, reset_state);
114 dev_err(rst->dev, "%s: set_device_resets failed (%d)\n",
123 * ti_sci_reset_assert() - assert device reset
124 * @rst: Handle to a single reset signal
126 * This function implements the reset driver op to assert a device's reset
127 * using the TI SCI protocol. This invokes the function ti_sci_reset_set()
128 * with the corresponding parameters as passed in, but with the @assert
129 * argument set to true for asserting the reset.
131 * Return: 0 for successful request, else a corresponding error value
133 static int ti_sci_reset_assert(struct reset_ctl *rst)
135 debug("%s(rst=%p)\n", __func__, rst);
136 return ti_sci_reset_set(rst, true);
140 * ti_sci_reset_deassert() - deassert device reset
141 * @rst: Handle to a single reset signal
143 * This function implements the reset driver op to deassert a device's reset
144 * using the TI SCI protocol. This invokes the function ti_sci_reset_set()
145 * with the corresponding parameters as passed in, but with the @assert
146 * argument set to false for deasserting the reset.
148 * Return: 0 for successful request, else a corresponding error value
150 static int ti_sci_reset_deassert(struct reset_ctl *rst)
152 debug("%s(rst=%p)\n", __func__, rst);
153 return ti_sci_reset_set(rst, false);
157 * ti_sci_reset_status() - check device reset status
158 * @rst: Handle to a single reset signal
160 * This function implements the reset driver op to return the status of a
161 * device's reset using the TI SCI protocol. The reset register value is read
162 * by invoking the TI SCI device operation .get_device_resets(), and the
163 * status of the specific reset is extracted and returned using this reset's
166 * Return: 0 if reset is deasserted, or a non-zero value if reset is asserted
168 static int ti_sci_reset_status(struct reset_ctl *rst)
170 struct ti_sci_reset_data *data = dev_get_priv(rst->dev);
171 const struct ti_sci_handle *sci = data->sci;
172 const struct ti_sci_dev_ops *dops = &sci->ops.dev_ops;
176 debug("%s(rst=%p)\n", __func__, rst);
178 ret = dops->get_device_resets(sci, rst->id, &reset_state);
180 dev_err(rst->dev, "%s: get_device_resets failed (%d)\n",
185 return reset_state & rst->data;
188 static const struct udevice_id ti_sci_reset_of_match[] = {
189 { .compatible = "ti,sci-reset", },
193 static struct reset_ops ti_sci_reset_ops = {
194 .of_xlate = ti_sci_reset_of_xlate,
195 .request = ti_sci_reset_request,
196 .rfree = ti_sci_reset_free,
197 .rst_assert = ti_sci_reset_assert,
198 .rst_deassert = ti_sci_reset_deassert,
199 .rst_status = ti_sci_reset_status,
202 U_BOOT_DRIVER(ti_sci_reset) = {
203 .name = "ti-sci-reset",
205 .of_match = ti_sci_reset_of_match,
206 .probe = ti_sci_reset_probe,
207 .priv_auto_alloc_size = sizeof(struct ti_sci_reset_data),
208 .ops = &ti_sci_reset_ops,