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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 struct reset_control *rst;
39 void __iomem *iomem;
40 u32 dma_requests;
41 u32 dmamux_requests;
42 spinlock_t lock;
43 unsigned long *dma_inuse;
44 u32 dma_reqs[];
45
46
47
48};
49
50static inline u32 stm32_dmamux_read(void __iomem *iomem, u32 reg)
51{
52 return readl_relaxed(iomem + reg);
53}
54
55static inline void stm32_dmamux_write(void __iomem *iomem, u32 reg, u32 val)
56{
57 writel_relaxed(val, iomem + reg);
58}
59
60static void stm32_dmamux_free(struct device *dev, void *route_data)
61{
62 struct stm32_dmamux_data *dmamux = dev_get_drvdata(dev);
63 struct stm32_dmamux *mux = route_data;
64 unsigned long flags;
65
66
67 spin_lock_irqsave(&dmamux->lock, flags);
68
69 stm32_dmamux_write(dmamux->iomem, STM32_DMAMUX_CCR(mux->chan_id), 0);
70 clear_bit(mux->chan_id, dmamux->dma_inuse);
71
72 pm_runtime_put_sync(dev);
73
74 spin_unlock_irqrestore(&dmamux->lock, flags);
75
76 dev_dbg(dev, "Unmapping DMAMUX(%u) to DMA%u(%u)\n",
77 mux->request, mux->master, mux->chan_id);
78
79 kfree(mux);
80}
81
82static void *stm32_dmamux_route_allocate(struct of_phandle_args *dma_spec,
83 struct of_dma *ofdma)
84{
85 struct platform_device *pdev = of_find_device_by_node(ofdma->of_node);
86 struct stm32_dmamux_data *dmamux = platform_get_drvdata(pdev);
87 struct stm32_dmamux *mux;
88 u32 i, min, max;
89 int ret;
90 unsigned long flags;
91
92 if (dma_spec->args_count != 3) {
93 dev_err(&pdev->dev, "invalid number of dma mux args\n");
94 return ERR_PTR(-EINVAL);
95 }
96
97 if (dma_spec->args[0] > dmamux->dmamux_requests) {
98 dev_err(&pdev->dev, "invalid mux request number: %d\n",
99 dma_spec->args[0]);
100 return ERR_PTR(-EINVAL);
101 }
102
103 mux = kzalloc(sizeof(*mux), GFP_KERNEL);
104 if (!mux)
105 return ERR_PTR(-ENOMEM);
106
107 spin_lock_irqsave(&dmamux->lock, flags);
108 mux->chan_id = find_first_zero_bit(dmamux->dma_inuse,
109 dmamux->dma_requests);
110
111 if (mux->chan_id == dmamux->dma_requests) {
112 spin_unlock_irqrestore(&dmamux->lock, flags);
113 dev_err(&pdev->dev, "Run out of free DMA requests\n");
114 ret = -ENOMEM;
115 goto error_chan_id;
116 }
117 set_bit(mux->chan_id, dmamux->dma_inuse);
118 spin_unlock_irqrestore(&dmamux->lock, flags);
119
120
121 for (i = 1, min = 0, max = dmamux->dma_reqs[i];
122 i <= dmamux->dma_reqs[0];
123 min += dmamux->dma_reqs[i], max += dmamux->dma_reqs[++i])
124 if (mux->chan_id < max)
125 break;
126 mux->master = i - 1;
127
128
129 dma_spec->np = of_parse_phandle(ofdma->of_node, "dma-masters", i - 1);
130 if (!dma_spec->np) {
131 dev_err(&pdev->dev, "can't get dma master\n");
132 ret = -EINVAL;
133 goto error;
134 }
135
136
137 spin_lock_irqsave(&dmamux->lock, flags);
138 ret = pm_runtime_get_sync(&pdev->dev);
139 if (ret < 0) {
140 spin_unlock_irqrestore(&dmamux->lock, flags);
141 goto error;
142 }
143 spin_unlock_irqrestore(&dmamux->lock, flags);
144
145 mux->request = dma_spec->args[0];
146
147
148 dma_spec->args[3] = dma_spec->args[2];
149 dma_spec->args[2] = dma_spec->args[1];
150 dma_spec->args[1] = 0;
151 dma_spec->args[0] = mux->chan_id - min;
152 dma_spec->args_count = 4;
153
154 stm32_dmamux_write(dmamux->iomem, STM32_DMAMUX_CCR(mux->chan_id),
155 mux->request);
156 dev_dbg(&pdev->dev, "Mapping DMAMUX(%u) to DMA%u(%u)\n",
157 mux->request, mux->master, mux->chan_id);
158
159 return mux;
160
161error:
162 clear_bit(mux->chan_id, dmamux->dma_inuse);
163
164error_chan_id:
165 kfree(mux);
166 return ERR_PTR(ret);
167}
168
169static const struct of_device_id stm32_stm32dma_master_match[] = {
170 { .compatible = "st,stm32-dma", },
171 {},
172};
173
174static int stm32_dmamux_probe(struct platform_device *pdev)
175{
176 struct device_node *node = pdev->dev.of_node;
177 const struct of_device_id *match;
178 struct device_node *dma_node;
179 struct stm32_dmamux_data *stm32_dmamux;
180 struct resource *res;
181 void __iomem *iomem;
182 int i, count, ret;
183 u32 dma_req;
184
185 if (!node)
186 return -ENODEV;
187
188 count = device_property_count_u32(&pdev->dev, "dma-masters");
189 if (count < 0) {
190 dev_err(&pdev->dev, "Can't get DMA master(s) node\n");
191 return -ENODEV;
192 }
193
194 stm32_dmamux = devm_kzalloc(&pdev->dev, sizeof(*stm32_dmamux) +
195 sizeof(u32) * (count + 1), GFP_KERNEL);
196 if (!stm32_dmamux)
197 return -ENOMEM;
198
199 dma_req = 0;
200 for (i = 1; i <= count; i++) {
201 dma_node = of_parse_phandle(node, "dma-masters", i - 1);
202
203 match = of_match_node(stm32_stm32dma_master_match, dma_node);
204 if (!match) {
205 dev_err(&pdev->dev, "DMA master is not supported\n");
206 of_node_put(dma_node);
207 return -EINVAL;
208 }
209
210 if (of_property_read_u32(dma_node, "dma-requests",
211 &stm32_dmamux->dma_reqs[i])) {
212 dev_info(&pdev->dev,
213 "Missing MUX output information, using %u.\n",
214 STM32_DMAMUX_MAX_DMA_REQUESTS);
215 stm32_dmamux->dma_reqs[i] =
216 STM32_DMAMUX_MAX_DMA_REQUESTS;
217 }
218 dma_req += stm32_dmamux->dma_reqs[i];
219 of_node_put(dma_node);
220 }
221
222 if (dma_req > STM32_DMAMUX_MAX_DMA_REQUESTS) {
223 dev_err(&pdev->dev, "Too many DMA Master Requests to manage\n");
224 return -ENODEV;
225 }
226
227 stm32_dmamux->dma_requests = dma_req;
228 stm32_dmamux->dma_reqs[0] = count;
229 stm32_dmamux->dma_inuse = devm_kcalloc(&pdev->dev,
230 BITS_TO_LONGS(dma_req),
231 sizeof(unsigned long),
232 GFP_KERNEL);
233 if (!stm32_dmamux->dma_inuse)
234 return -ENOMEM;
235
236 if (device_property_read_u32(&pdev->dev, "dma-requests",
237 &stm32_dmamux->dmamux_requests)) {
238 stm32_dmamux->dmamux_requests = STM32_DMAMUX_MAX_REQUESTS;
239 dev_warn(&pdev->dev, "DMAMUX defaulting on %u requests\n",
240 stm32_dmamux->dmamux_requests);
241 }
242 pm_runtime_get_noresume(&pdev->dev);
243
244 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
245 iomem = devm_ioremap_resource(&pdev->dev, res);
246 if (IS_ERR(iomem))
247 return PTR_ERR(iomem);
248
249 spin_lock_init(&stm32_dmamux->lock);
250
251 stm32_dmamux->clk = devm_clk_get(&pdev->dev, NULL);
252 if (IS_ERR(stm32_dmamux->clk)) {
253 ret = PTR_ERR(stm32_dmamux->clk);
254 if (ret == -EPROBE_DEFER)
255 dev_info(&pdev->dev, "Missing controller clock\n");
256 return ret;
257 }
258
259 stm32_dmamux->rst = devm_reset_control_get(&pdev->dev, NULL);
260 if (!IS_ERR(stm32_dmamux->rst)) {
261 reset_control_assert(stm32_dmamux->rst);
262 udelay(2);
263 reset_control_deassert(stm32_dmamux->rst);
264 }
265
266 stm32_dmamux->iomem = iomem;
267 stm32_dmamux->dmarouter.dev = &pdev->dev;
268 stm32_dmamux->dmarouter.route_free = stm32_dmamux_free;
269
270 platform_set_drvdata(pdev, stm32_dmamux);
271 pm_runtime_set_active(&pdev->dev);
272 pm_runtime_enable(&pdev->dev);
273
274 if (!IS_ERR(stm32_dmamux->clk)) {
275 ret = clk_prepare_enable(stm32_dmamux->clk);
276 if (ret < 0) {
277 dev_err(&pdev->dev, "clk_prep_enable error: %d\n", ret);
278 return ret;
279 }
280 }
281
282 pm_runtime_get_noresume(&pdev->dev);
283
284
285 for (i = 0; i < stm32_dmamux->dma_requests; i++)
286 stm32_dmamux_write(stm32_dmamux->iomem, STM32_DMAMUX_CCR(i), 0);
287
288 pm_runtime_put(&pdev->dev);
289
290 return of_dma_router_register(node, stm32_dmamux_route_allocate,
291 &stm32_dmamux->dmarouter);
292}
293
294#ifdef CONFIG_PM
295static int stm32_dmamux_runtime_suspend(struct device *dev)
296{
297 struct platform_device *pdev = to_platform_device(dev);
298 struct stm32_dmamux_data *stm32_dmamux = platform_get_drvdata(pdev);
299
300 clk_disable_unprepare(stm32_dmamux->clk);
301
302 return 0;
303}
304
305static int stm32_dmamux_runtime_resume(struct device *dev)
306{
307 struct platform_device *pdev = to_platform_device(dev);
308 struct stm32_dmamux_data *stm32_dmamux = platform_get_drvdata(pdev);
309 int ret;
310
311 ret = clk_prepare_enable(stm32_dmamux->clk);
312 if (ret) {
313 dev_err(&pdev->dev, "failed to prepare_enable clock\n");
314 return ret;
315 }
316
317 return 0;
318}
319#endif
320
321static const struct dev_pm_ops stm32_dmamux_pm_ops = {
322 SET_RUNTIME_PM_OPS(stm32_dmamux_runtime_suspend,
323 stm32_dmamux_runtime_resume, NULL)
324};
325
326static const struct of_device_id stm32_dmamux_match[] = {
327 { .compatible = "st,stm32h7-dmamux" },
328 {},
329};
330
331static struct platform_driver stm32_dmamux_driver = {
332 .probe = stm32_dmamux_probe,
333 .driver = {
334 .name = "stm32-dmamux",
335 .of_match_table = stm32_dmamux_match,
336 .pm = &stm32_dmamux_pm_ops,
337 },
338};
339
340static int __init stm32_dmamux_init(void)
341{
342 return platform_driver_register(&stm32_dmamux_driver);
343}
344arch_initcall(stm32_dmamux_init);
345
346MODULE_DESCRIPTION("DMA Router driver for STM32 DMA MUX");
347MODULE_AUTHOR("M'boumba Cedric Madianga <cedric.madianga@gmail.com>");
348MODULE_AUTHOR("Pierre-Yves Mordret <pierre-yves.mordret@st.com>");
349MODULE_LICENSE("GPL v2");
350
