1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 *
4 * Copyright (C) STMicroelectronics SA 2017
5 * Author(s): M'boumba Cedric Madianga <cedric.madianga@gmail.com>
6 * Pierre-Yves Mordret <pierre-yves.mordret@st.com>
7 *
8 * DMA Router driver for STM32 DMA MUX
9 *
10 * Based on TI DMA Crossbar driver
11 */
12
13 #include <linux/clk.h>
14 #include <linux/delay.h>
15 #include <linux/err.h>
16 #include <linux/init.h>
17 #include <linux/module.h>
18 #include <linux/of.h>
19 #include <linux/of_dma.h>
20 #include <linux/of_platform.h>
21 #include <linux/platform_device.h>
22 #include <linux/pm_runtime.h>
23 #include <linux/reset.h>
24 #include <linux/slab.h>
25 #include <linux/spinlock.h>
26
27 #define STM32_DMAMUX_CCR(x) (0x4 * (x))
28 #define STM32_DMAMUX_MAX_DMA_REQUESTS 32
29 #define STM32_DMAMUX_MAX_REQUESTS 255
30
31 struct stm32_dmamux {
32 u32 master;
33 u32 request;
34 u32 chan_id;
35 };
36
37 struct stm32_dmamux_data {
38 struct dma_router dmarouter;
39 struct clk *clk;
40 void __iomem *iomem;
41 u32 dma_requests; /* Number of DMA requests connected to DMAMUX */
42 u32 dmamux_requests; /* Number of DMA requests routed toward DMAs */
43 spinlock_t lock; /* Protects register access */
44 DECLARE_BITMAP(dma_inuse, STM32_DMAMUX_MAX_DMA_REQUESTS); /* Used DMA channel */
45 u32 ccr[STM32_DMAMUX_MAX_DMA_REQUESTS]; /* Used to backup CCR register
46 * in suspend
47 */
48 u32 dma_reqs[]; /* Number of DMA Request per DMA masters.
49 * [0] holds number of DMA Masters.
50 * To be kept at very end of this structure
51 */
52 };
53
stm32_dmamux_read(void __iomem * iomem,u32 reg)54 static inline u32 stm32_dmamux_read(void __iomem *iomem, u32 reg)
55 {
56 return readl_relaxed(iomem + reg);
57 }
58
stm32_dmamux_write(void __iomem * iomem,u32 reg,u32 val)59 static inline void stm32_dmamux_write(void __iomem *iomem, u32 reg, u32 val)
60 {
61 writel_relaxed(val, iomem + reg);
62 }
63
stm32_dmamux_free(struct device * dev,void * route_data)64 static void stm32_dmamux_free(struct device *dev, void *route_data)
65 {
66 struct stm32_dmamux_data *dmamux = dev_get_drvdata(dev);
67 struct stm32_dmamux *mux = route_data;
68 unsigned long flags;
69
70 /* Clear dma request */
71 spin_lock_irqsave(&dmamux->lock, flags);
72
73 stm32_dmamux_write(dmamux->iomem, STM32_DMAMUX_CCR(mux->chan_id), 0);
74 clear_bit(mux->chan_id, dmamux->dma_inuse);
75
76 pm_runtime_put_sync(dev);
77
78 spin_unlock_irqrestore(&dmamux->lock, flags);
79
80 dev_dbg(dev, "Unmapping DMAMUX(%u) to DMA%u(%u)\n",
81 mux->request, mux->master, mux->chan_id);
82
83 kfree(mux);
84 }
85
stm32_dmamux_route_allocate(struct of_phandle_args * dma_spec,struct of_dma * ofdma)86 static void *stm32_dmamux_route_allocate(struct of_phandle_args *dma_spec,
87 struct of_dma *ofdma)
88 {
89 struct platform_device *pdev = of_find_device_by_node(ofdma->of_node);
90 struct stm32_dmamux_data *dmamux = platform_get_drvdata(pdev);
91 struct stm32_dmamux *mux;
92 u32 i, min, max;
93 int ret;
94 unsigned long flags;
95
96 if (dma_spec->args_count != 3) {
97 dev_err(&pdev->dev, "invalid number of dma mux args\n");
98 return ERR_PTR(-EINVAL);
99 }
100
101 if (dma_spec->args[0] > dmamux->dmamux_requests) {
102 dev_err(&pdev->dev, "invalid mux request number: %d\n",
103 dma_spec->args[0]);
104 return ERR_PTR(-EINVAL);
105 }
106
107 mux = kzalloc(sizeof(*mux), GFP_KERNEL);
108 if (!mux)
109 return ERR_PTR(-ENOMEM);
110
111 spin_lock_irqsave(&dmamux->lock, flags);
112 mux->chan_id = find_first_zero_bit(dmamux->dma_inuse,
113 dmamux->dma_requests);
114
115 if (mux->chan_id == dmamux->dma_requests) {
116 spin_unlock_irqrestore(&dmamux->lock, flags);
117 dev_err(&pdev->dev, "Run out of free DMA requests\n");
118 ret = -ENOMEM;
119 goto error_chan_id;
120 }
121 set_bit(mux->chan_id, dmamux->dma_inuse);
122 spin_unlock_irqrestore(&dmamux->lock, flags);
123
124 /* Look for DMA Master */
125 for (i = 1, min = 0, max = dmamux->dma_reqs[i];
126 i <= dmamux->dma_reqs[0];
127 min += dmamux->dma_reqs[i], max += dmamux->dma_reqs[++i])
128 if (mux->chan_id < max)
129 break;
130 mux->master = i - 1;
131
132 /* The of_node_put() will be done in of_dma_router_xlate function */
133 dma_spec->np = of_parse_phandle(ofdma->of_node, "dma-masters", i - 1);
134 if (!dma_spec->np) {
135 dev_err(&pdev->dev, "can't get dma master\n");
136 ret = -EINVAL;
137 goto error;
138 }
139
140 /* Set dma request */
141 spin_lock_irqsave(&dmamux->lock, flags);
142 ret = pm_runtime_resume_and_get(&pdev->dev);
143 if (ret < 0) {
144 spin_unlock_irqrestore(&dmamux->lock, flags);
145 goto error;
146 }
147 spin_unlock_irqrestore(&dmamux->lock, flags);
148
149 mux->request = dma_spec->args[0];
150
151 /* craft DMA spec */
152 dma_spec->args[3] = dma_spec->args[2] | mux->chan_id << 16;
153 dma_spec->args[2] = dma_spec->args[1];
154 dma_spec->args[1] = 0;
155 dma_spec->args[0] = mux->chan_id - min;
156 dma_spec->args_count = 4;
157
158 stm32_dmamux_write(dmamux->iomem, STM32_DMAMUX_CCR(mux->chan_id),
159 mux->request);
160 dev_dbg(&pdev->dev, "Mapping DMAMUX(%u) to DMA%u(%u)\n",
161 mux->request, mux->master, mux->chan_id);
162
163 return mux;
164
165 error:
166 clear_bit(mux->chan_id, dmamux->dma_inuse);
167
168 error_chan_id:
169 kfree(mux);
170 return ERR_PTR(ret);
171 }
172
173 static const struct of_device_id stm32_stm32dma_master_match[] __maybe_unused = {
174 { .compatible = "st,stm32-dma", },
175 {},
176 };
177
stm32_dmamux_probe(struct platform_device * pdev)178 static int stm32_dmamux_probe(struct platform_device *pdev)
179 {
180 struct device_node *node = pdev->dev.of_node;
181 const struct of_device_id *match;
182 struct device_node *dma_node;
183 struct stm32_dmamux_data *stm32_dmamux;
184 void __iomem *iomem;
185 struct reset_control *rst;
186 int i, count, ret;
187 u32 dma_req;
188
189 if (!node)
190 return -ENODEV;
191
192 count = device_property_count_u32(&pdev->dev, "dma-masters");
193 if (count < 0) {
194 dev_err(&pdev->dev, "Can't get DMA master(s) node\n");
195 return -ENODEV;
196 }
197
198 stm32_dmamux = devm_kzalloc(&pdev->dev, sizeof(*stm32_dmamux) +
199 sizeof(u32) * (count + 1), GFP_KERNEL);
200 if (!stm32_dmamux)
201 return -ENOMEM;
202
203 dma_req = 0;
204 for (i = 1; i <= count; i++) {
205 dma_node = of_parse_phandle(node, "dma-masters", i - 1);
206
207 match = of_match_node(stm32_stm32dma_master_match, dma_node);
208 if (!match) {
209 dev_err(&pdev->dev, "DMA master is not supported\n");
210 of_node_put(dma_node);
211 return -EINVAL;
212 }
213
214 if (of_property_read_u32(dma_node, "dma-requests",
215 &stm32_dmamux->dma_reqs[i])) {
216 dev_info(&pdev->dev,
217 "Missing MUX output information, using %u.\n",
218 STM32_DMAMUX_MAX_DMA_REQUESTS);
219 stm32_dmamux->dma_reqs[i] =
220 STM32_DMAMUX_MAX_DMA_REQUESTS;
221 }
222 dma_req += stm32_dmamux->dma_reqs[i];
223 of_node_put(dma_node);
224 }
225
226 if (dma_req > STM32_DMAMUX_MAX_DMA_REQUESTS) {
227 dev_err(&pdev->dev, "Too many DMA Master Requests to manage\n");
228 return -ENODEV;
229 }
230
231 stm32_dmamux->dma_requests = dma_req;
232 stm32_dmamux->dma_reqs[0] = count;
233
234 if (device_property_read_u32(&pdev->dev, "dma-requests",
235 &stm32_dmamux->dmamux_requests)) {
236 stm32_dmamux->dmamux_requests = STM32_DMAMUX_MAX_REQUESTS;
237 dev_warn(&pdev->dev, "DMAMUX defaulting on %u requests\n",
238 stm32_dmamux->dmamux_requests);
239 }
240 pm_runtime_get_noresume(&pdev->dev);
241
242 iomem = devm_platform_ioremap_resource(pdev, 0);
243 if (IS_ERR(iomem))
244 return PTR_ERR(iomem);
245
246 spin_lock_init(&stm32_dmamux->lock);
247
248 stm32_dmamux->clk = devm_clk_get(&pdev->dev, NULL);
249 if (IS_ERR(stm32_dmamux->clk))
250 return dev_err_probe(&pdev->dev, PTR_ERR(stm32_dmamux->clk),
251 "Missing clock controller\n");
252
253 ret = clk_prepare_enable(stm32_dmamux->clk);
254 if (ret < 0) {
255 dev_err(&pdev->dev, "clk_prep_enable error: %d\n", ret);
256 return ret;
257 }
258
259 rst = devm_reset_control_get(&pdev->dev, NULL);
260 if (IS_ERR(rst)) {
261 ret = PTR_ERR(rst);
262 if (ret == -EPROBE_DEFER)
263 goto err_clk;
264 } else if (count > 1) { /* Don't reset if there is only one dma-master */
265 reset_control_assert(rst);
266 udelay(2);
267 reset_control_deassert(rst);
268 }
269
270 stm32_dmamux->iomem = iomem;
271 stm32_dmamux->dmarouter.dev = &pdev->dev;
272 stm32_dmamux->dmarouter.route_free = stm32_dmamux_free;
273
274 platform_set_drvdata(pdev, stm32_dmamux);
275 pm_runtime_set_active(&pdev->dev);
276 pm_runtime_enable(&pdev->dev);
277
278 pm_runtime_get_noresume(&pdev->dev);
279
280 /* Reset the dmamux */
281 for (i = 0; i < stm32_dmamux->dma_requests; i++)
282 stm32_dmamux_write(stm32_dmamux->iomem, STM32_DMAMUX_CCR(i), 0);
283
284 pm_runtime_put(&pdev->dev);
285
286 ret = of_dma_router_register(node, stm32_dmamux_route_allocate,
287 &stm32_dmamux->dmarouter);
288 if (ret)
289 goto pm_disable;
290
291 return 0;
292
293 pm_disable:
294 pm_runtime_disable(&pdev->dev);
295 err_clk:
296 clk_disable_unprepare(stm32_dmamux->clk);
297
298 return ret;
299 }
300
301 #ifdef CONFIG_PM
stm32_dmamux_runtime_suspend(struct device * dev)302 static int stm32_dmamux_runtime_suspend(struct device *dev)
303 {
304 struct platform_device *pdev = to_platform_device(dev);
305 struct stm32_dmamux_data *stm32_dmamux = platform_get_drvdata(pdev);
306
307 clk_disable_unprepare(stm32_dmamux->clk);
308
309 return 0;
310 }
311
stm32_dmamux_runtime_resume(struct device * dev)312 static int stm32_dmamux_runtime_resume(struct device *dev)
313 {
314 struct platform_device *pdev = to_platform_device(dev);
315 struct stm32_dmamux_data *stm32_dmamux = platform_get_drvdata(pdev);
316 int ret;
317
318 ret = clk_prepare_enable(stm32_dmamux->clk);
319 if (ret) {
320 dev_err(&pdev->dev, "failed to prepare_enable clock\n");
321 return ret;
322 }
323
324 return 0;
325 }
326 #endif
327
328 #ifdef CONFIG_PM_SLEEP
stm32_dmamux_suspend(struct device * dev)329 static int stm32_dmamux_suspend(struct device *dev)
330 {
331 struct platform_device *pdev = to_platform_device(dev);
332 struct stm32_dmamux_data *stm32_dmamux = platform_get_drvdata(pdev);
333 int i, ret;
334
335 ret = pm_runtime_resume_and_get(dev);
336 if (ret < 0)
337 return ret;
338
339 for (i = 0; i < stm32_dmamux->dma_requests; i++)
340 stm32_dmamux->ccr[i] = stm32_dmamux_read(stm32_dmamux->iomem,
341 STM32_DMAMUX_CCR(i));
342
343 pm_runtime_put_sync(dev);
344
345 pm_runtime_force_suspend(dev);
346
347 return 0;
348 }
349
stm32_dmamux_resume(struct device * dev)350 static int stm32_dmamux_resume(struct device *dev)
351 {
352 struct platform_device *pdev = to_platform_device(dev);
353 struct stm32_dmamux_data *stm32_dmamux = platform_get_drvdata(pdev);
354 int i, ret;
355
356 ret = pm_runtime_force_resume(dev);
357 if (ret < 0)
358 return ret;
359
360 ret = pm_runtime_resume_and_get(dev);
361 if (ret < 0)
362 return ret;
363
364 for (i = 0; i < stm32_dmamux->dma_requests; i++)
365 stm32_dmamux_write(stm32_dmamux->iomem, STM32_DMAMUX_CCR(i),
366 stm32_dmamux->ccr[i]);
367
368 pm_runtime_put_sync(dev);
369
370 return 0;
371 }
372 #endif
373
374 static const struct dev_pm_ops stm32_dmamux_pm_ops = {
375 SET_SYSTEM_SLEEP_PM_OPS(stm32_dmamux_suspend, stm32_dmamux_resume)
376 SET_RUNTIME_PM_OPS(stm32_dmamux_runtime_suspend,
377 stm32_dmamux_runtime_resume, NULL)
378 };
379
380 static const struct of_device_id stm32_dmamux_match[] = {
381 { .compatible = "st,stm32h7-dmamux" },
382 {},
383 };
384
385 static struct platform_driver stm32_dmamux_driver = {
386 .probe = stm32_dmamux_probe,
387 .driver = {
388 .name = "stm32-dmamux",
389 .of_match_table = stm32_dmamux_match,
390 .pm = &stm32_dmamux_pm_ops,
391 },
392 };
393
stm32_dmamux_init(void)394 static int __init stm32_dmamux_init(void)
395 {
396 return platform_driver_register(&stm32_dmamux_driver);
397 }
398 arch_initcall(stm32_dmamux_init);
399
400 MODULE_DESCRIPTION("DMA Router driver for STM32 DMA MUX");
401 MODULE_AUTHOR("M'boumba Cedric Madianga <cedric.madianga@gmail.com>");
402 MODULE_AUTHOR("Pierre-Yves Mordret <pierre-yves.mordret@st.com>");
403