net: sungem: fix rx checksum support
[linux/fpc-iii.git] / drivers / reset / reset-ti-sci.c
blobbf68729ab72925ea1df58cfb67130db4d151a0e4
1 /*
2 * Texas Instrument's System Control Interface (TI-SCI) reset driver
4 * Copyright (C) 2015-2017 Texas Instruments Incorporated - http://www.ti.com/
5 * Andrew F. Davis <afd@ti.com>
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
11 * This program is distributed "as is" WITHOUT ANY WARRANTY of any
12 * kind, whether express or implied; without even the implied warranty
13 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
17 #include <linux/idr.h>
18 #include <linux/module.h>
19 #include <linux/mutex.h>
20 #include <linux/of.h>
21 #include <linux/platform_device.h>
22 #include <linux/reset-controller.h>
23 #include <linux/soc/ti/ti_sci_protocol.h>
25 /**
26 * struct ti_sci_reset_control - reset control structure
27 * @dev_id: SoC-specific device identifier
28 * @reset_mask: reset mask to use for toggling reset
29 * @lock: synchronize reset_mask read-modify-writes
31 struct ti_sci_reset_control {
32 u32 dev_id;
33 u32 reset_mask;
34 struct mutex lock;
37 /**
38 * struct ti_sci_reset_data - reset controller information structure
39 * @rcdev: reset controller entity
40 * @dev: reset controller device pointer
41 * @sci: TI SCI handle used for communication with system controller
42 * @idr: idr structure for mapping ids to reset control structures
44 struct ti_sci_reset_data {
45 struct reset_controller_dev rcdev;
46 struct device *dev;
47 const struct ti_sci_handle *sci;
48 struct idr idr;
51 #define to_ti_sci_reset_data(p) \
52 container_of((p), struct ti_sci_reset_data, rcdev)
54 /**
55 * ti_sci_reset_set() - program a device's reset
56 * @rcdev: reset controller entity
57 * @id: ID of the reset to toggle
58 * @assert: boolean flag to indicate assert or deassert
60 * This is a common internal function used to assert or deassert a device's
61 * reset using the TI SCI protocol. The device's reset is asserted if the
62 * @assert argument is true, or deasserted if @assert argument is false.
63 * The mechanism itself is a read-modify-write procedure, the current device
64 * reset register is read using a TI SCI device operation, the new value is
65 * set or un-set using the reset's mask, and the new reset value written by
66 * using another TI SCI device operation.
68 * Return: 0 for successful request, else a corresponding error value
70 static int ti_sci_reset_set(struct reset_controller_dev *rcdev,
71 unsigned long id, bool assert)
73 struct ti_sci_reset_data *data = to_ti_sci_reset_data(rcdev);
74 const struct ti_sci_handle *sci = data->sci;
75 const struct ti_sci_dev_ops *dev_ops = &sci->ops.dev_ops;
76 struct ti_sci_reset_control *control;
77 u32 reset_state;
78 int ret;
80 control = idr_find(&data->idr, id);
81 if (!control)
82 return -EINVAL;
84 mutex_lock(&control->lock);
86 ret = dev_ops->get_device_resets(sci, control->dev_id, &reset_state);
87 if (ret)
88 goto out;
90 if (assert)
91 reset_state |= control->reset_mask;
92 else
93 reset_state &= ~control->reset_mask;
95 ret = dev_ops->set_device_resets(sci, control->dev_id, reset_state);
96 out:
97 mutex_unlock(&control->lock);
99 return ret;
103 * ti_sci_reset_assert() - assert device reset
104 * @rcdev: reset controller entity
105 * @id: ID of the reset to be asserted
107 * This function implements the reset driver op to assert a device's reset
108 * using the TI SCI protocol. This invokes the function ti_sci_reset_set()
109 * with the corresponding parameters as passed in, but with the @assert
110 * argument set to true for asserting the reset.
112 * Return: 0 for successful request, else a corresponding error value
114 static int ti_sci_reset_assert(struct reset_controller_dev *rcdev,
115 unsigned long id)
117 return ti_sci_reset_set(rcdev, id, true);
121 * ti_sci_reset_deassert() - deassert device reset
122 * @rcdev: reset controller entity
123 * @id: ID of the reset to be deasserted
125 * This function implements the reset driver op to deassert a device's reset
126 * using the TI SCI protocol. This invokes the function ti_sci_reset_set()
127 * with the corresponding parameters as passed in, but with the @assert
128 * argument set to false for deasserting the reset.
130 * Return: 0 for successful request, else a corresponding error value
132 static int ti_sci_reset_deassert(struct reset_controller_dev *rcdev,
133 unsigned long id)
135 return ti_sci_reset_set(rcdev, id, false);
139 * ti_sci_reset_status() - check device reset status
140 * @rcdev: reset controller entity
141 * @id: ID of reset to be checked
143 * This function implements the reset driver op to return the status of a
144 * device's reset using the TI SCI protocol. The reset register value is read
145 * by invoking the TI SCI device operation .get_device_resets(), and the
146 * status of the specific reset is extracted and returned using this reset's
147 * reset mask.
149 * Return: 0 if reset is deasserted, or a non-zero value if reset is asserted
151 static int ti_sci_reset_status(struct reset_controller_dev *rcdev,
152 unsigned long id)
154 struct ti_sci_reset_data *data = to_ti_sci_reset_data(rcdev);
155 const struct ti_sci_handle *sci = data->sci;
156 const struct ti_sci_dev_ops *dev_ops = &sci->ops.dev_ops;
157 struct ti_sci_reset_control *control;
158 u32 reset_state;
159 int ret;
161 control = idr_find(&data->idr, id);
162 if (!control)
163 return -EINVAL;
165 ret = dev_ops->get_device_resets(sci, control->dev_id, &reset_state);
166 if (ret)
167 return ret;
169 return reset_state & control->reset_mask;
172 static const struct reset_control_ops ti_sci_reset_ops = {
173 .assert = ti_sci_reset_assert,
174 .deassert = ti_sci_reset_deassert,
175 .status = ti_sci_reset_status,
179 * ti_sci_reset_of_xlate() - translate a set of OF arguments to a reset ID
180 * @rcdev: reset controller entity
181 * @reset_spec: OF reset argument specifier
183 * This function performs the translation of the reset argument specifier
184 * values defined in a reset consumer device node. The function allocates a
185 * reset control structure for that device reset, and will be used by the
186 * driver for performing any reset functions on that reset. An idr structure
187 * is allocated and used to map to the reset control structure. This idr
188 * is used by the driver to do reset lookups.
190 * Return: 0 for successful request, else a corresponding error value
192 static int ti_sci_reset_of_xlate(struct reset_controller_dev *rcdev,
193 const struct of_phandle_args *reset_spec)
195 struct ti_sci_reset_data *data = to_ti_sci_reset_data(rcdev);
196 struct ti_sci_reset_control *control;
198 if (WARN_ON(reset_spec->args_count != rcdev->of_reset_n_cells))
199 return -EINVAL;
201 control = devm_kzalloc(data->dev, sizeof(*control), GFP_KERNEL);
202 if (!control)
203 return -ENOMEM;
205 control->dev_id = reset_spec->args[0];
206 control->reset_mask = reset_spec->args[1];
207 mutex_init(&control->lock);
209 return idr_alloc(&data->idr, control, 0, 0, GFP_KERNEL);
212 static const struct of_device_id ti_sci_reset_of_match[] = {
213 { .compatible = "ti,sci-reset", },
214 { /* sentinel */ },
216 MODULE_DEVICE_TABLE(of, ti_sci_reset_of_match);
218 static int ti_sci_reset_probe(struct platform_device *pdev)
220 struct ti_sci_reset_data *data;
222 if (!pdev->dev.of_node)
223 return -ENODEV;
225 data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
226 if (!data)
227 return -ENOMEM;
229 data->sci = devm_ti_sci_get_handle(&pdev->dev);
230 if (IS_ERR(data->sci))
231 return PTR_ERR(data->sci);
233 data->rcdev.ops = &ti_sci_reset_ops;
234 data->rcdev.owner = THIS_MODULE;
235 data->rcdev.of_node = pdev->dev.of_node;
236 data->rcdev.of_reset_n_cells = 2;
237 data->rcdev.of_xlate = ti_sci_reset_of_xlate;
238 data->dev = &pdev->dev;
239 idr_init(&data->idr);
241 platform_set_drvdata(pdev, data);
243 return reset_controller_register(&data->rcdev);
246 static int ti_sci_reset_remove(struct platform_device *pdev)
248 struct ti_sci_reset_data *data = platform_get_drvdata(pdev);
250 reset_controller_unregister(&data->rcdev);
252 idr_destroy(&data->idr);
254 return 0;
257 static struct platform_driver ti_sci_reset_driver = {
258 .probe = ti_sci_reset_probe,
259 .remove = ti_sci_reset_remove,
260 .driver = {
261 .name = "ti-sci-reset",
262 .of_match_table = ti_sci_reset_of_match,
265 module_platform_driver(ti_sci_reset_driver);
267 MODULE_AUTHOR("Andrew F. Davis <afd@ti.com>");
268 MODULE_DESCRIPTION("TI System Control Interface (TI SCI) Reset driver");
269 MODULE_LICENSE("GPL v2");