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...
14 #include <reset-uclass.h>
15 #include <linux/err.h>
16 #include <linux/soc/ti/ti_sci_protocol.h>
19 * struct ti_sci_reset_data - reset controller information structure
20 * @sci: TI SCI handle used for communication with system controller
22 struct ti_sci_reset_data {
23 const struct ti_sci_handle *sci;
26 static int ti_sci_reset_probe(struct udevice *dev)
28 struct ti_sci_reset_data *data = dev_get_priv(dev);
30 debug("%s(dev=%p)\n", __func__, dev);
35 /* Store handle for communication with the system controller */
36 data->sci = ti_sci_get_handle(dev);
37 if (IS_ERR(data->sci))
38 return PTR_ERR(data->sci);
43 static int ti_sci_reset_of_xlate(struct reset_ctl *rst,
44 struct ofnode_phandle_args *args)
46 debug("%s(rst=%p, args_count=%d)\n", __func__, rst, args->args_count);
48 if (args->args_count != 2) {
49 debug("Invalid args_count: %d\n", args->args_count);
54 * On TI SCI-based devices, the reset provider id field is used as a
55 * device ID, and the data field is used as the associated reset mask.
57 rst->id = args->args[0];
58 rst->data = args->args[1];
63 static int ti_sci_reset_request(struct reset_ctl *rst)
65 debug("%s(rst=%p)\n", __func__, rst);
69 static int ti_sci_reset_free(struct reset_ctl *rst)
71 debug("%s(rst=%p)\n", __func__, rst);
76 * ti_sci_reset_set() - program a device's reset
77 * @rst: Handle to a single reset signal
78 * @assert: boolean flag to indicate assert or deassert
80 * This is a common internal function used to assert or deassert a device's
81 * reset using the TI SCI protocol. The device's reset is asserted if the
82 * @assert argument is true, or deasserted if @assert argument is false.
83 * The mechanism itself is a read-modify-write procedure, the current device
84 * reset register is read using a TI SCI device operation, the new value is
85 * set or un-set using the reset's mask, and the new reset value written by
86 * using another TI SCI device operation.
88 * Return: 0 for successful request, else a corresponding error value
90 static int ti_sci_reset_set(struct reset_ctl *rst, bool assert)
92 struct ti_sci_reset_data *data = dev_get_priv(rst->dev);
93 const struct ti_sci_handle *sci = data->sci;
94 const struct ti_sci_dev_ops *dops = &sci->ops.dev_ops;
98 ret = dops->get_device_resets(sci, rst->id, &reset_state);
100 dev_err(rst->dev, "%s: get_device_resets failed (%d)\n",
106 reset_state |= rst->data;
108 reset_state &= ~rst->data;
110 ret = dops->set_device_resets(sci, rst->id, reset_state);
112 dev_err(rst->dev, "%s: set_device_resets failed (%d)\n",
121 * ti_sci_reset_assert() - assert device reset
122 * @rst: Handle to a single reset signal
124 * This function implements the reset driver op to assert a device's reset
125 * using the TI SCI protocol. This invokes the function ti_sci_reset_set()
126 * with the corresponding parameters as passed in, but with the @assert
127 * argument set to true for asserting the reset.
129 * Return: 0 for successful request, else a corresponding error value
131 static int ti_sci_reset_assert(struct reset_ctl *rst)
133 debug("%s(rst=%p)\n", __func__, rst);
134 return ti_sci_reset_set(rst, true);
138 * ti_sci_reset_deassert() - deassert device reset
139 * @rst: Handle to a single reset signal
141 * This function implements the reset driver op to deassert a device's reset
142 * using the TI SCI protocol. This invokes the function ti_sci_reset_set()
143 * with the corresponding parameters as passed in, but with the @assert
144 * argument set to false for deasserting the reset.
146 * Return: 0 for successful request, else a corresponding error value
148 static int ti_sci_reset_deassert(struct reset_ctl *rst)
150 debug("%s(rst=%p)\n", __func__, rst);
151 return ti_sci_reset_set(rst, false);
155 * ti_sci_reset_status() - check device reset status
156 * @rst: Handle to a single reset signal
158 * This function implements the reset driver op to return the status of a
159 * device's reset using the TI SCI protocol. The reset register value is read
160 * by invoking the TI SCI device operation .get_device_resets(), and the
161 * status of the specific reset is extracted and returned using this reset's
164 * Return: 0 if reset is deasserted, or a non-zero value if reset is asserted
166 static int ti_sci_reset_status(struct reset_ctl *rst)
168 struct ti_sci_reset_data *data = dev_get_priv(rst->dev);
169 const struct ti_sci_handle *sci = data->sci;
170 const struct ti_sci_dev_ops *dops = &sci->ops.dev_ops;
174 debug("%s(rst=%p)\n", __func__, rst);
176 ret = dops->get_device_resets(sci, rst->id, &reset_state);
178 dev_err(rst->dev, "%s: get_device_resets failed (%d)\n",
183 return reset_state & rst->data;
186 static const struct udevice_id ti_sci_reset_of_match[] = {
187 { .compatible = "ti,sci-reset", },
191 static struct reset_ops ti_sci_reset_ops = {
192 .of_xlate = ti_sci_reset_of_xlate,
193 .request = ti_sci_reset_request,
194 .rfree = ti_sci_reset_free,
195 .rst_assert = ti_sci_reset_assert,
196 .rst_deassert = ti_sci_reset_deassert,
197 .rst_status = ti_sci_reset_status,
200 U_BOOT_DRIVER(ti_sci_reset) = {
201 .name = "ti-sci-reset",
203 .of_match = ti_sci_reset_of_match,
204 .probe = ti_sci_reset_probe,
205 .priv_auto_alloc_size = sizeof(struct ti_sci_reset_data),
206 .ops = &ti_sci_reset_ops,