drivers/dma/stm32-dmamux.c

   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
  54 static inline u32 stm32_dmamux_read(void __iomem *iomem, u32 reg)
  55 {
  56         return readl_relaxed(iomem + reg);
  57 }
  58
  59 static inline void stm32_dmamux_write(void __iomem *iomem, u32 reg, u32 val)
  60 {
  61         writel_relaxed(val, iomem + reg);
  62 }
  63
  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
  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
 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
 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
 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
 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
 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
 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>");