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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_device.h>
19#include <linux/of_dma.h>
20#include <linux/pm_runtime.h>
21#include <linux/reset.h>
22#include <linux/slab.h>
23#include <linux/spinlock.h>
24
25#define STM32_DMAMUX_CCR(x) (0x4 * (x))
26#define STM32_DMAMUX_MAX_DMA_REQUESTS 32
27#define STM32_DMAMUX_MAX_REQUESTS 255
28
29struct stm32_dmamux {
30 u32 master;
31 u32 request;
32 u32 chan_id;
33};
34
35struct stm32_dmamux_data {
36 struct dma_router dmarouter;
37 struct clk *clk;
38 void __iomem *iomem;
39 u32 dma_requests; /* Number of DMA requests connected to DMAMUX */
40 u32 dmamux_requests; /* Number of DMA requests routed toward DMAs */
41 spinlock_t lock; /* Protects register access */
42 DECLARE_BITMAP(dma_inuse, STM32_DMAMUX_MAX_DMA_REQUESTS); /* Used DMA channel */
43 u32 ccr[STM32_DMAMUX_MAX_DMA_REQUESTS]; /* Used to backup CCR register
44 * in suspend
45 */
46 u32 dma_reqs[]; /* Number of DMA Request per DMA masters.
47 * [0] holds number of DMA Masters.
48 * To be kept at very end of this structure
49 */
50};
51
52static inline u32 stm32_dmamux_read(void __iomem *iomem, u32 reg)
53{
54 return readl_relaxed(iomem + reg);
55}
56
57static inline void stm32_dmamux_write(void __iomem *iomem, u32 reg, u32 val)
58{
59 writel_relaxed(val, iomem + reg);
60}
61
62static void stm32_dmamux_free(struct device *dev, void *route_data)
63{
64 struct stm32_dmamux_data *dmamux = dev_get_drvdata(dev);
65 struct stm32_dmamux *mux = route_data;
66 unsigned long flags;
67
68 /* Clear dma request */
69 spin_lock_irqsave(&dmamux->lock, flags);
70
71 stm32_dmamux_write(dmamux->iomem, STM32_DMAMUX_CCR(mux->chan_id), 0);
72 clear_bit(mux->chan_id, dmamux->dma_inuse);
73
74 pm_runtime_put_sync(dev);
75
76 spin_unlock_irqrestore(&dmamux->lock, flags);
77
78 dev_dbg(dev, "Unmapping DMAMUX(%u) to DMA%u(%u)\n",
79 mux->request, mux->master, mux->chan_id);
80
81 kfree(mux);
82}
83
84static void *stm32_dmamux_route_allocate(struct of_phandle_args *dma_spec,
85 struct of_dma *ofdma)
86{
87 struct platform_device *pdev = of_find_device_by_node(ofdma->of_node);
88 struct stm32_dmamux_data *dmamux = platform_get_drvdata(pdev);
89 struct stm32_dmamux *mux;
90 u32 i, min, max;
91 int ret;
92 unsigned long flags;
93
94 if (dma_spec->args_count != 3) {
95 dev_err(&pdev->dev, "invalid number of dma mux args\n");
96 return ERR_PTR(-EINVAL);
97 }
98
99 if (dma_spec->args[0] > dmamux->dmamux_requests) {
100 dev_err(&pdev->dev, "invalid mux request number: %d\n",
101 dma_spec->args[0]);
102 return ERR_PTR(-EINVAL);
103 }
104
105 mux = kzalloc(sizeof(*mux), GFP_KERNEL);
106 if (!mux)
107 return ERR_PTR(-ENOMEM);
108
109 spin_lock_irqsave(&dmamux->lock, flags);
110 mux->chan_id = find_first_zero_bit(dmamux->dma_inuse,
111 dmamux->dma_requests);
112
113 if (mux->chan_id == dmamux->dma_requests) {
114 spin_unlock_irqrestore(&dmamux->lock, flags);
115 dev_err(&pdev->dev, "Run out of free DMA requests\n");
116 ret = -ENOMEM;
117 goto error_chan_id;
118 }
119 set_bit(mux->chan_id, dmamux->dma_inuse);
120 spin_unlock_irqrestore(&dmamux->lock, flags);
121
122 /* Look for DMA Master */
123 for (i = 1, min = 0, max = dmamux->dma_reqs[i];
124 i <= dmamux->dma_reqs[0];
125 min += dmamux->dma_reqs[i], max += dmamux->dma_reqs[++i])
126 if (mux->chan_id < max)
127 break;
128 mux->master = i - 1;
129
130 /* The of_node_put() will be done in of_dma_router_xlate function */
131 dma_spec->np = of_parse_phandle(ofdma->of_node, "dma-masters", i - 1);
132 if (!dma_spec->np) {
133 dev_err(&pdev->dev, "can't get dma master\n");
134 ret = -EINVAL;
135 goto error;
136 }
137
138 /* Set dma request */
139 spin_lock_irqsave(&dmamux->lock, flags);
140 ret = pm_runtime_resume_and_get(&pdev->dev);
141 if (ret < 0) {
142 spin_unlock_irqrestore(&dmamux->lock, flags);
143 goto error;
144 }
145 spin_unlock_irqrestore(&dmamux->lock, flags);
146
147 mux->request = dma_spec->args[0];
148
149 /* craft DMA spec */
150 dma_spec->args[3] = dma_spec->args[2] | mux->chan_id << 16;
151 dma_spec->args[2] = dma_spec->args[1];
152 dma_spec->args[1] = 0;
153 dma_spec->args[0] = mux->chan_id - min;
154 dma_spec->args_count = 4;
155
156 stm32_dmamux_write(dmamux->iomem, STM32_DMAMUX_CCR(mux->chan_id),
157 mux->request);
158 dev_dbg(&pdev->dev, "Mapping DMAMUX(%u) to DMA%u(%u)\n",
159 mux->request, mux->master, mux->chan_id);
160
161 return mux;
162
163error:
164 clear_bit(mux->chan_id, dmamux->dma_inuse);
165
166error_chan_id:
167 kfree(mux);
168 return ERR_PTR(ret);
169}
170
171static const struct of_device_id stm32_stm32dma_master_match[] __maybe_unused = {
172 { .compatible = "st,stm32-dma", },
173 {},
174};
175
176static int stm32_dmamux_probe(struct platform_device *pdev)
177{
178 struct device_node *node = pdev->dev.of_node;
179 const struct of_device_id *match;
180 struct device_node *dma_node;
181 struct stm32_dmamux_data *stm32_dmamux;
182 struct resource *res;
183 void __iomem *iomem;
184 struct reset_control *rst;
185 int i, count, ret;
186 u32 dma_req;
187
188 if (!node)
189 return -ENODEV;
190
191 count = device_property_count_u32(&pdev->dev, "dma-masters");
192 if (count < 0) {
193 dev_err(&pdev->dev, "Can't get DMA master(s) node\n");
194 return -ENODEV;
195 }
196
197 stm32_dmamux = devm_kzalloc(&pdev->dev, sizeof(*stm32_dmamux) +
198 sizeof(u32) * (count + 1), GFP_KERNEL);
199 if (!stm32_dmamux)
200 return -ENOMEM;
201
202 dma_req = 0;
203 for (i = 1; i <= count; i++) {
204 dma_node = of_parse_phandle(node, "dma-masters", i - 1);
205
206 match = of_match_node(stm32_stm32dma_master_match, dma_node);
207 if (!match) {
208 dev_err(&pdev->dev, "DMA master is not supported\n");
209 of_node_put(dma_node);
210 return -EINVAL;
211 }
212
213 if (of_property_read_u32(dma_node, "dma-requests",
214 &stm32_dmamux->dma_reqs[i])) {
215 dev_info(&pdev->dev,
216 "Missing MUX output information, using %u.\n",
217 STM32_DMAMUX_MAX_DMA_REQUESTS);
218 stm32_dmamux->dma_reqs[i] =
219 STM32_DMAMUX_MAX_DMA_REQUESTS;
220 }
221 dma_req += stm32_dmamux->dma_reqs[i];
222 of_node_put(dma_node);
223 }
224
225 if (dma_req > STM32_DMAMUX_MAX_DMA_REQUESTS) {
226 dev_err(&pdev->dev, "Too many DMA Master Requests to manage\n");
227 return -ENODEV;
228 }
229
230 stm32_dmamux->dma_requests = dma_req;
231 stm32_dmamux->dma_reqs[0] = count;
232
233 if (device_property_read_u32(&pdev->dev, "dma-requests",
234 &stm32_dmamux->dmamux_requests)) {
235 stm32_dmamux->dmamux_requests = STM32_DMAMUX_MAX_REQUESTS;
236 dev_warn(&pdev->dev, "DMAMUX defaulting on %u requests\n",
237 stm32_dmamux->dmamux_requests);
238 }
239 pm_runtime_get_noresume(&pdev->dev);
240
241 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
242 iomem = devm_ioremap_resource(&pdev->dev, res);
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
293pm_disable:
294 pm_runtime_disable(&pdev->dev);
295err_clk:
296 clk_disable_unprepare(stm32_dmamux->clk);
297
298 return ret;
299}
300
301#ifdef CONFIG_PM
302static 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
312static 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
329static 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
350static 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
374static 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
380static const struct of_device_id stm32_dmamux_match[] = {
381 { .compatible = "st,stm32h7-dmamux" },
382 {},
383};
384
385static 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
394static int __init stm32_dmamux_init(void)
395{
396 return platform_driver_register(&stm32_dmamux_driver);
397}
398arch_initcall(stm32_dmamux_init);
399
400MODULE_DESCRIPTION("DMA Router driver for STM32 DMA MUX");
401MODULE_AUTHOR("M'boumba Cedric Madianga <cedric.madianga@gmail.com>");
402MODULE_AUTHOR("Pierre-Yves Mordret <pierre-yves.mordret@st.com>");
403MODULE_LICENSE("GPL v2");