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_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
  29 struct stm32_dmamux {
  30         u32 master;
  31         u32 request;
  32         u32 chan_id;
  33 };
  34
  35 struct 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
  52 static inline u32 stm32_dmamux_read(void __iomem *iomem, u32 reg)
  53 {
  54         return readl_relaxed(iomem + reg);
  55 }
  56
  57 static inline void stm32_dmamux_write(void __iomem *iomem, u32 reg, u32 val)
  58 {
  59         writel_relaxed(val, iomem + reg);
  60 }
  61
  62 static 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
  84 static 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
 163 error:
 164         clear_bit(mux->chan_id, dmamux->dma_inuse);
 165
 166 error_chan_id:
 167         kfree(mux);
 168         return ERR_PTR(ret);
 169 }
 170
 171 static const struct of_device_id stm32_stm32dma_master_match[] __maybe_unused = {
 172         { .compatible = "st,stm32-dma", },
 173         {},
 174 };
 175
 176 static 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         void __iomem *iomem;
 183         struct reset_control *rst;
 184         int i, count, ret;
 185         u32 dma_req;
 186
 187         if (!node)
 188                 return -ENODEV;
 189
 190         count = device_property_count_u32(&pdev->dev, "dma-masters");
 191         if (count < 0) {
 192                 dev_err(&pdev->dev, "Can't get DMA master(s) node\n");
 193                 return -ENODEV;
 194         }
 195
 196         stm32_dmamux = devm_kzalloc(&pdev->dev, sizeof(*stm32_dmamux) +
 197                                     sizeof(u32) * (count + 1), GFP_KERNEL);
 198         if (!stm32_dmamux)
 199                 return -ENOMEM;
 200
 201         dma_req = 0;
 202         for (i = 1; i <= count; i++) {
 203                 dma_node = of_parse_phandle(node, "dma-masters", i - 1);
 204
 205                 match = of_match_node(stm32_stm32dma_master_match, dma_node);
 206                 if (!match) {
 207                         dev_err(&pdev->dev, "DMA master is not supported\n");
 208                         of_node_put(dma_node);
 209                         return -EINVAL;
 210                 }
 211
 212                 if (of_property_read_u32(dma_node, "dma-requests",
 213                                          &stm32_dmamux->dma_reqs[i])) {
 214                         dev_info(&pdev->dev,
 215                                  "Missing MUX output information, using %u.\n",
 216                                  STM32_DMAMUX_MAX_DMA_REQUESTS);
 217                         stm32_dmamux->dma_reqs[i] =
 218                                 STM32_DMAMUX_MAX_DMA_REQUESTS;
 219                 }
 220                 dma_req += stm32_dmamux->dma_reqs[i];
 221                 of_node_put(dma_node);
 222         }
 223
 224         if (dma_req > STM32_DMAMUX_MAX_DMA_REQUESTS) {
 225                 dev_err(&pdev->dev, "Too many DMA Master Requests to manage\n");
 226                 return -ENODEV;
 227         }
 228
 229         stm32_dmamux->dma_requests = dma_req;
 230         stm32_dmamux->dma_reqs[0] = count;
 231
 232         if (device_property_read_u32(&pdev->dev, "dma-requests",
 233                                      &stm32_dmamux->dmamux_requests)) {
 234                 stm32_dmamux->dmamux_requests = STM32_DMAMUX_MAX_REQUESTS;
 235                 dev_warn(&pdev->dev, "DMAMUX defaulting on %u requests\n",
 236                          stm32_dmamux->dmamux_requests);
 237         }
 238         pm_runtime_get_noresume(&pdev->dev);
 239
 240         iomem = devm_platform_ioremap_resource(pdev, 0);
 241         if (IS_ERR(iomem))
 242                 return PTR_ERR(iomem);
 243
 244         spin_lock_init(&stm32_dmamux->lock);
 245
 246         stm32_dmamux->clk = devm_clk_get(&pdev->dev, NULL);
 247         if (IS_ERR(stm32_dmamux->clk))
 248                 return dev_err_probe(&pdev->dev, PTR_ERR(stm32_dmamux->clk),
 249                                      "Missing clock controller\n");
 250
 251         ret = clk_prepare_enable(stm32_dmamux->clk);
 252         if (ret < 0) {
 253                 dev_err(&pdev->dev, "clk_prep_enable error: %d\n", ret);
 254                 return ret;
 255         }
 256
 257         rst = devm_reset_control_get(&pdev->dev, NULL);
 258         if (IS_ERR(rst)) {
 259                 ret = PTR_ERR(rst);
 260                 if (ret == -EPROBE_DEFER)
 261                         goto err_clk;
 262         } else if (count > 1) { /* Don't reset if there is only one dma-master */
 263                 reset_control_assert(rst);
 264                 udelay(2);
 265                 reset_control_deassert(rst);
 266         }
 267
 268         stm32_dmamux->iomem = iomem;
 269         stm32_dmamux->dmarouter.dev = &pdev->dev;
 270         stm32_dmamux->dmarouter.route_free = stm32_dmamux_free;
 271
 272         platform_set_drvdata(pdev, stm32_dmamux);
 273         pm_runtime_set_active(&pdev->dev);
 274         pm_runtime_enable(&pdev->dev);
 275
 276         pm_runtime_get_noresume(&pdev->dev);
 277
 278         /* Reset the dmamux */
 279         for (i = 0; i < stm32_dmamux->dma_requests; i++)
 280                 stm32_dmamux_write(stm32_dmamux->iomem, STM32_DMAMUX_CCR(i), 0);
 281
 282         pm_runtime_put(&pdev->dev);
 283
 284         ret = of_dma_router_register(node, stm32_dmamux_route_allocate,
 285                                      &stm32_dmamux->dmarouter);
 286         if (ret)
 287                 goto pm_disable;
 288
 289         return 0;
 290
 291 pm_disable:
 292         pm_runtime_disable(&pdev->dev);
 293 err_clk:
 294         clk_disable_unprepare(stm32_dmamux->clk);
 295
 296         return ret;
 297 }
 298
 299 #ifdef CONFIG_PM
 300 static int stm32_dmamux_runtime_suspend(struct device *dev)
 301 {
 302         struct platform_device *pdev = to_platform_device(dev);
 303         struct stm32_dmamux_data *stm32_dmamux = platform_get_drvdata(pdev);
 304
 305         clk_disable_unprepare(stm32_dmamux->clk);
 306
 307         return 0;
 308 }
 309
 310 static int stm32_dmamux_runtime_resume(struct device *dev)
 311 {
 312         struct platform_device *pdev = to_platform_device(dev);
 313         struct stm32_dmamux_data *stm32_dmamux = platform_get_drvdata(pdev);
 314         int ret;
 315
 316         ret = clk_prepare_enable(stm32_dmamux->clk);
 317         if (ret) {
 318                 dev_err(&pdev->dev, "failed to prepare_enable clock\n");
 319                 return ret;
 320         }
 321
 322         return 0;
 323 }
 324 #endif
 325
 326 #ifdef CONFIG_PM_SLEEP
 327 static int stm32_dmamux_suspend(struct device *dev)
 328 {
 329         struct platform_device *pdev = to_platform_device(dev);
 330         struct stm32_dmamux_data *stm32_dmamux = platform_get_drvdata(pdev);
 331         int i, ret;
 332
 333         ret = pm_runtime_resume_and_get(dev);
 334         if (ret < 0)
 335                 return ret;
 336
 337         for (i = 0; i < stm32_dmamux->dma_requests; i++)
 338                 stm32_dmamux->ccr[i] = stm32_dmamux_read(stm32_dmamux->iomem,
 339                                                          STM32_DMAMUX_CCR(i));
 340
 341         pm_runtime_put_sync(dev);
 342
 343         pm_runtime_force_suspend(dev);
 344
 345         return 0;
 346 }
 347
 348 static int stm32_dmamux_resume(struct device *dev)
 349 {
 350         struct platform_device *pdev = to_platform_device(dev);
 351         struct stm32_dmamux_data *stm32_dmamux = platform_get_drvdata(pdev);
 352         int i, ret;
 353
 354         ret = pm_runtime_force_resume(dev);
 355         if (ret < 0)
 356                 return ret;
 357
 358         ret = pm_runtime_resume_and_get(dev);
 359         if (ret < 0)
 360                 return ret;
 361
 362         for (i = 0; i < stm32_dmamux->dma_requests; i++)
 363                 stm32_dmamux_write(stm32_dmamux->iomem, STM32_DMAMUX_CCR(i),
 364                                    stm32_dmamux->ccr[i]);
 365
 366         pm_runtime_put_sync(dev);
 367
 368         return 0;
 369 }
 370 #endif
 371
 372 static const struct dev_pm_ops stm32_dmamux_pm_ops = {
 373         SET_SYSTEM_SLEEP_PM_OPS(stm32_dmamux_suspend, stm32_dmamux_resume)
 374         SET_RUNTIME_PM_OPS(stm32_dmamux_runtime_suspend,
 375                            stm32_dmamux_runtime_resume, NULL)
 376 };
 377
 378 static const struct of_device_id stm32_dmamux_match[] = {
 379         { .compatible = "st,stm32h7-dmamux" },
 380         {},
 381 };
 382
 383 static struct platform_driver stm32_dmamux_driver = {
 384         .probe  = stm32_dmamux_probe,
 385         .driver = {
 386                 .name = "stm32-dmamux",
 387                 .of_match_table = stm32_dmamux_match,
 388                 .pm = &stm32_dmamux_pm_ops,
 389         },
 390 };
 391
 392 static int __init stm32_dmamux_init(void)
 393 {
 394         return platform_driver_register(&stm32_dmamux_driver);
 395 }
 396 arch_initcall(stm32_dmamux_init);
 397
 398 MODULE_DESCRIPTION("DMA Router driver for STM32 DMA MUX");
 399 MODULE_AUTHOR("M'boumba Cedric Madianga <cedric.madianga@gmail.com>");
 400 MODULE_AUTHOR("Pierre-Yves Mordret <pierre-yves.mordret@st.com>");
 401 MODULE_LICENSE("GPL v2");