1/*
  2 * ST's Remote Processor Control Driver
  3 *
  4 * Copyright (C) 2015 STMicroelectronics - All Rights Reserved
  5 *
  6 * Author: Ludovic Barre <ludovic.barre@st.com>
  7 *
  8 * This program is free software; you can redistribute it and/or modify
  9 * it under the terms of the GNU General Public License version 2 as
 10 * published by the Free Software Foundation.
 11 */
 12
 13#include <linux/clk.h>
 14#include <linux/dma-mapping.h>
 15#include <linux/err.h>
 16#include <linux/interrupt.h>
 17#include <linux/kernel.h>
 18#include <linux/mfd/syscon.h>
 19#include <linux/module.h>
 20#include <linux/of.h>
 21#include <linux/of_device.h>
 22#include <linux/of_reserved_mem.h>
 23#include <linux/platform_device.h>
 24#include <linux/regmap.h>
 25#include <linux/remoteproc.h>
 26#include <linux/reset.h>
 27
 28struct st_rproc_config {
 29	bool			sw_reset;
 30	bool			pwr_reset;
 31	unsigned long		bootaddr_mask;
 32};
 33
 34struct st_rproc {
 35	struct st_rproc_config	*config;
 36	struct reset_control	*sw_reset;
 37	struct reset_control	*pwr_reset;
 38	struct clk		*clk;
 39	u32			clk_rate;
 40	struct regmap		*boot_base;
 41	u32			boot_offset;
 42};
 43
 44static int st_rproc_start(struct rproc *rproc)
 45{
 46	struct st_rproc *ddata = rproc->priv;
 47	int err;
 48
 49	regmap_update_bits(ddata->boot_base, ddata->boot_offset,
 50			   ddata->config->bootaddr_mask, rproc->bootaddr);
 51
 52	err = clk_enable(ddata->clk);
 53	if (err) {
 54		dev_err(&rproc->dev, "Failed to enable clock\n");
 55		return err;
 56	}
 57
 58	if (ddata->config->sw_reset) {
 59		err = reset_control_deassert(ddata->sw_reset);
 60		if (err) {
 61			dev_err(&rproc->dev, "Failed to deassert S/W Reset\n");
 62			goto sw_reset_fail;
 63		}
 64	}
 65
 66	if (ddata->config->pwr_reset) {
 67		err = reset_control_deassert(ddata->pwr_reset);
 68		if (err) {
 69			dev_err(&rproc->dev, "Failed to deassert Power Reset\n");
 70			goto pwr_reset_fail;
 71		}
 72	}
 73
 74	dev_info(&rproc->dev, "Started from 0x%x\n", rproc->bootaddr);
 75
 76	return 0;
 77
 78
 79pwr_reset_fail:
 80	if (ddata->config->pwr_reset)
 81		reset_control_assert(ddata->sw_reset);
 82sw_reset_fail:
 83	clk_disable(ddata->clk);
 84
 85	return err;
 86}
 87
 88static int st_rproc_stop(struct rproc *rproc)
 89{
 90	struct st_rproc *ddata = rproc->priv;
 91	int sw_err = 0, pwr_err = 0;
 92
 93	if (ddata->config->sw_reset) {
 94		sw_err = reset_control_assert(ddata->sw_reset);
 95		if (sw_err)
 96			dev_err(&rproc->dev, "Failed to assert S/W Reset\n");
 97	}
 98
 99	if (ddata->config->pwr_reset) {
100		pwr_err = reset_control_assert(ddata->pwr_reset);
101		if (pwr_err)
102			dev_err(&rproc->dev, "Failed to assert Power Reset\n");
103	}
104
105	clk_disable(ddata->clk);
106
107	return sw_err ?: pwr_err;
108}
109
110static struct rproc_ops st_rproc_ops = {
111	.start		= st_rproc_start,
112	.stop		= st_rproc_stop,
113};
114
115/*
116 * Fetch state of the processor: 0 is off, 1 is on.
117 */
118static int st_rproc_state(struct platform_device *pdev)
119{
120	struct rproc *rproc = platform_get_drvdata(pdev);
121	struct st_rproc *ddata = rproc->priv;
122	int reset_sw = 0, reset_pwr = 0;
123
124	if (ddata->config->sw_reset)
125		reset_sw = reset_control_status(ddata->sw_reset);
126
127	if (ddata->config->pwr_reset)
128		reset_pwr = reset_control_status(ddata->pwr_reset);
129
130	if (reset_sw < 0 || reset_pwr < 0)
131		return -EINVAL;
132
133	return !reset_sw && !reset_pwr;
134}
135
136static const struct st_rproc_config st40_rproc_cfg = {
137	.sw_reset = true,
138	.pwr_reset = true,
139	.bootaddr_mask = GENMASK(28, 1),
140};
141
142static const struct st_rproc_config st231_rproc_cfg = {
143	.sw_reset = true,
144	.pwr_reset = false,
145	.bootaddr_mask = GENMASK(31, 6),
146};
147
148static const struct of_device_id st_rproc_match[] = {
149	{ .compatible = "st,st40-rproc", .data = &st40_rproc_cfg },
150	{ .compatible = "st,st231-rproc", .data = &st231_rproc_cfg },
151	{},
152};
153MODULE_DEVICE_TABLE(of, st_rproc_match);
154
155static int st_rproc_parse_dt(struct platform_device *pdev)
156{
157	struct device *dev = &pdev->dev;
158	struct rproc *rproc = platform_get_drvdata(pdev);
159	struct st_rproc *ddata = rproc->priv;
160	struct device_node *np = dev->of_node;
161	int err;
162
163	if (ddata->config->sw_reset) {
164		ddata->sw_reset = devm_reset_control_get(dev, "sw_reset");
165		if (IS_ERR(ddata->sw_reset)) {
166			dev_err(dev, "Failed to get S/W Reset\n");
167			return PTR_ERR(ddata->sw_reset);
168		}
169	}
170
171	if (ddata->config->pwr_reset) {
172		ddata->pwr_reset = devm_reset_control_get(dev, "pwr_reset");
173		if (IS_ERR(ddata->pwr_reset)) {
174			dev_err(dev, "Failed to get Power Reset\n");
175			return PTR_ERR(ddata->pwr_reset);
176		}
177	}
178
179	ddata->clk = devm_clk_get(dev, NULL);
180	if (IS_ERR(ddata->clk)) {
181		dev_err(dev, "Failed to get clock\n");
182		return PTR_ERR(ddata->clk);
183	}
184
185	err = of_property_read_u32(np, "clock-frequency", &ddata->clk_rate);
186	if (err) {
187		dev_err(dev, "failed to get clock frequency\n");
188		return err;
189	}
190
191	ddata->boot_base = syscon_regmap_lookup_by_phandle(np, "st,syscfg");
192	if (IS_ERR(ddata->boot_base)) {
193		dev_err(dev, "Boot base not found\n");
194		return PTR_ERR(ddata->boot_base);
195	}
196
197	err = of_property_read_u32_index(np, "st,syscfg", 1,
198					 &ddata->boot_offset);
199	if (err) {
200		dev_err(dev, "Boot offset not found\n");
201		return -EINVAL;
202	}
203
204	err = of_reserved_mem_device_init(dev);
205	if (err) {
206		dev_err(dev, "Failed to obtain shared memory\n");
207		return err;
208	}
209
210	err = clk_prepare(ddata->clk);
211	if (err)
212		dev_err(dev, "failed to get clock\n");
213
214	return err;
215}
216
217static int st_rproc_probe(struct platform_device *pdev)
218{
219	struct device *dev = &pdev->dev;
220	const struct of_device_id *match;
221	struct st_rproc *ddata;
222	struct device_node *np = dev->of_node;
223	struct rproc *rproc;
224	int enabled;
225	int ret;
226
227	match = of_match_device(st_rproc_match, dev);
228	if (!match || !match->data) {
229		dev_err(dev, "No device match found\n");
230		return -ENODEV;
231	}
232
233	rproc = rproc_alloc(dev, np->name, &st_rproc_ops, NULL, sizeof(*ddata));
234	if (!rproc)
235		return -ENOMEM;
236
237	rproc->has_iommu = false;
238	ddata = rproc->priv;
239	ddata->config = (struct st_rproc_config *)match->data;
240
241	platform_set_drvdata(pdev, rproc);
242
243	ret = st_rproc_parse_dt(pdev);
244	if (ret)
245		goto free_rproc;
246
247	enabled = st_rproc_state(pdev);
248	if (enabled < 0) {
249		ret = enabled;
250		goto free_rproc;
251	}
252
253	if (enabled) {
254		atomic_inc(&rproc->power);
255		rproc->state = RPROC_RUNNING;
256	} else {
257		clk_set_rate(ddata->clk, ddata->clk_rate);
258	}
259
260	ret = rproc_add(rproc);
261	if (ret)
262		goto free_rproc;
263
264	return 0;
265
266free_rproc:
267	rproc_free(rproc);
268	return ret;
269}
270
271static int st_rproc_remove(struct platform_device *pdev)
272{
273	struct rproc *rproc = platform_get_drvdata(pdev);
274	struct st_rproc *ddata = rproc->priv;
275
276	rproc_del(rproc);
277
278	clk_disable_unprepare(ddata->clk);
279
280	of_reserved_mem_device_release(&pdev->dev);
281
282	rproc_free(rproc);
283
284	return 0;
285}
286
287static struct platform_driver st_rproc_driver = {
288	.probe = st_rproc_probe,
289	.remove = st_rproc_remove,
290	.driver = {
291		.name = "st-rproc",
292		.of_match_table = of_match_ptr(st_rproc_match),
293	},
294};
295module_platform_driver(st_rproc_driver);
296
297MODULE_DESCRIPTION("ST Remote Processor Control Driver");
298MODULE_AUTHOR("Ludovic Barre <ludovic.barre@st.com>");
299MODULE_LICENSE("GPL v2");