drivers/dma/stm32-dmamux.c

   1 /*
   2  *
   3  * Copyright (C) STMicroelectronics SA 2017
   4  * Author(s): M'boumba Cedric Madianga <cedric.madianga@gmail.com>
   5  *            Pierre-Yves Mordret <pierre-yves.mordret@st.com>
   6  *
   7  * License terms: GPL V2.0.
   8  *
   9  * This program is free software; you can redistribute it and/or modify it
  10  * under the terms of the GNU General Public License version 2 as published by
  11  * the Free Software Foundation.
  12  *
  13  * This program is distributed in the hope that it will be useful, but
  14  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  15  * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
  16  * details.
  17  *
  18  * DMA Router driver for STM32 DMA MUX
  19  *
  20  * Based on TI DMA Crossbar driver
  21  *
  22  */
  23
  24 #include <linux/clk.h>
  25 #include <linux/delay.h>
  26 #include <linux/err.h>
  27 #include <linux/init.h>
  28 #include <linux/module.h>
  29 #include <linux/of_device.h>
  30 #include <linux/of_dma.h>
  31 #include <linux/reset.h>
  32 #include <linux/slab.h>
  33 #include <linux/spinlock.h>
  34
  35 #define STM32_DMAMUX_CCR(x)             (0x4 * (x))
  36 #define STM32_DMAMUX_MAX_DMA_REQUESTS   32
  37 #define STM32_DMAMUX_MAX_REQUESTS       255
  38
  39 struct stm32_dmamux {
  40         u32 master;
  41         u32 request;
  42         u32 chan_id;
  43 };
  44
  45 struct stm32_dmamux_data {
  46         struct dma_router dmarouter;
  47         struct clk *clk;
  48         struct reset_control *rst;
  49         void __iomem *iomem;
  50         u32 dma_requests; /* Number of DMA requests connected to DMAMUX */
  51         u32 dmamux_requests; /* Number of DMA requests routed toward DMAs */
  52         spinlock_t lock; /* Protects register access */
  53         unsigned long *dma_inuse; /* Used DMA channel */
  54         u32 dma_reqs[]; /* Number of DMA Request per DMA masters.
  55                          *  [0] holds number of DMA Masters.
  56                          *  To be kept at very end end of this structure
  57                          */
  58 };
  59
  60 static inline u32 stm32_dmamux_read(void __iomem *iomem, u32 reg)
  61 {
  62         return readl_relaxed(iomem + reg);
  63 }
  64
  65 static inline void stm32_dmamux_write(void __iomem *iomem, u32 reg, u32 val)
  66 {
  67         writel_relaxed(val, iomem + reg);
  68 }
  69
  70 static void stm32_dmamux_free(struct device *dev, void *route_data)
  71 {
  72         struct stm32_dmamux_data *dmamux = dev_get_drvdata(dev);
  73         struct stm32_dmamux *mux = route_data;
  74         unsigned long flags;
  75
  76         /* Clear dma request */
  77         spin_lock_irqsave(&dmamux->lock, flags);
  78
  79         stm32_dmamux_write(dmamux->iomem, STM32_DMAMUX_CCR(mux->chan_id), 0);
  80         clear_bit(mux->chan_id, dmamux->dma_inuse);
  81
  82         if (!IS_ERR(dmamux->clk))
  83                 clk_disable(dmamux->clk);
  84
  85         spin_unlock_irqrestore(&dmamux->lock, flags);
  86
  87         dev_dbg(dev, "Unmapping DMAMUX(%u) to DMA%u(%u)\n",
  88                 mux->request, mux->master, mux->chan_id);
  89
  90         kfree(mux);
  91 }
  92
  93 static void *stm32_dmamux_route_allocate(struct of_phandle_args *dma_spec,
  94                                          struct of_dma *ofdma)
  95 {
  96         struct platform_device *pdev = of_find_device_by_node(ofdma->of_node);
  97         struct stm32_dmamux_data *dmamux = platform_get_drvdata(pdev);
  98         struct stm32_dmamux *mux;
  99         u32 i, min, max;
 100         int ret;
 101         unsigned long flags;
 102
 103         if (dma_spec->args_count != 3) {
 104                 dev_err(&pdev->dev, "invalid number of dma mux args\n");
 105                 return ERR_PTR(-EINVAL);
 106         }
 107
 108         if (dma_spec->args[0] > dmamux->dmamux_requests) {
 109                 dev_err(&pdev->dev, "invalid mux request number: %d\n",
 110                         dma_spec->args[0]);
 111                 return ERR_PTR(-EINVAL);
 112         }
 113
 114         mux = kzalloc(sizeof(*mux), GFP_KERNEL);
 115         if (!mux)
 116                 return ERR_PTR(-ENOMEM);
 117
 118         spin_lock_irqsave(&dmamux->lock, flags);
 119         mux->chan_id = find_first_zero_bit(dmamux->dma_inuse,
 120                                            dmamux->dma_requests);
 121
 122         if (mux->chan_id == dmamux->dma_requests) {
 123                 spin_unlock_irqrestore(&dmamux->lock, flags);
 124                 dev_err(&pdev->dev, "Run out of free DMA requests\n");
 125                 ret = -ENOMEM;
 126                 goto error_chan_id;
 127         }
 128         set_bit(mux->chan_id, dmamux->dma_inuse);
 129         spin_unlock_irqrestore(&dmamux->lock, flags);
 130
 131         /* Look for DMA Master */
 132         for (i = 1, min = 0, max = dmamux->dma_reqs[i];
 133              i <= dmamux->dma_reqs[0];
 134              min += dmamux->dma_reqs[i], max += dmamux->dma_reqs[++i])
 135                 if (mux->chan_id < max)
 136                         break;
 137         mux->master = i - 1;
 138
 139         /* The of_node_put() will be done in of_dma_router_xlate function */
 140         dma_spec->np = of_parse_phandle(ofdma->of_node, "dma-masters", i - 1);
 141         if (!dma_spec->np) {
 142                 dev_err(&pdev->dev, "can't get dma master\n");
 143                 ret = -EINVAL;
 144                 goto error;
 145         }
 146
 147         /* Set dma request */
 148         spin_lock_irqsave(&dmamux->lock, flags);
 149         if (!IS_ERR(dmamux->clk)) {
 150                 ret = clk_enable(dmamux->clk);
 151                 if (ret < 0) {
 152                         spin_unlock_irqrestore(&dmamux->lock, flags);
 153                         dev_err(&pdev->dev, "clk_prep_enable issue: %d\n", ret);
 154                         goto error;
 155                 }
 156         }
 157         spin_unlock_irqrestore(&dmamux->lock, flags);
 158
 159         mux->request = dma_spec->args[0];
 160
 161         /*  craft DMA spec */
 162         dma_spec->args[3] = dma_spec->args[2];
 163         dma_spec->args[2] = dma_spec->args[1];
 164         dma_spec->args[1] = 0;
 165         dma_spec->args[0] = mux->chan_id - min;
 166         dma_spec->args_count = 4;
 167
 168         stm32_dmamux_write(dmamux->iomem, STM32_DMAMUX_CCR(mux->chan_id),
 169                            mux->request);
 170         dev_dbg(&pdev->dev, "Mapping DMAMUX(%u) to DMA%u(%u)\n",
 171                 mux->request, mux->master, mux->chan_id);
 172
 173         return mux;
 174
 175 error:
 176         clear_bit(mux->chan_id, dmamux->dma_inuse);
 177
 178 error_chan_id:
 179         kfree(mux);
 180         return ERR_PTR(ret);
 181 }
 182
 183 static const struct of_device_id stm32_stm32dma_master_match[] = {
 184         { .compatible = "st,stm32-dma", },
 185         {},
 186 };
 187
 188 static int stm32_dmamux_probe(struct platform_device *pdev)
 189 {
 190         struct device_node *node = pdev->dev.of_node;
 191         const struct of_device_id *match;
 192         struct device_node *dma_node;
 193         struct stm32_dmamux_data *stm32_dmamux;
 194         struct resource *res;
 195         void __iomem *iomem;
 196         int i, count, ret;
 197         u32 dma_req;
 198
 199         if (!node)
 200                 return -ENODEV;
 201
 202         count = device_property_read_u32_array(&pdev->dev, "dma-masters",
 203                                                NULL, 0);
 204         if (count < 0) {
 205                 dev_err(&pdev->dev, "Can't get DMA master(s) node\n");
 206                 return -ENODEV;
 207         }
 208
 209         stm32_dmamux = devm_kzalloc(&pdev->dev, sizeof(*stm32_dmamux) +
 210                                     sizeof(u32) * (count + 1), GFP_KERNEL);
 211         if (!stm32_dmamux)
 212                 return -ENOMEM;
 213
 214         dma_req = 0;
 215         for (i = 1; i <= count; i++) {
 216                 dma_node = of_parse_phandle(node, "dma-masters", i - 1);
 217
 218                 match = of_match_node(stm32_stm32dma_master_match, dma_node);
 219                 if (!match) {
 220                         dev_err(&pdev->dev, "DMA master is not supported\n");
 221                         of_node_put(dma_node);
 222                         return -EINVAL;
 223                 }
 224
 225                 if (of_property_read_u32(dma_node, "dma-requests",
 226                                          &stm32_dmamux->dma_reqs[i])) {
 227                         dev_info(&pdev->dev,
 228                                  "Missing MUX output information, using %u.\n",
 229                                  STM32_DMAMUX_MAX_DMA_REQUESTS);
 230                         stm32_dmamux->dma_reqs[i] =
 231                                 STM32_DMAMUX_MAX_DMA_REQUESTS;
 232                 }
 233                 dma_req += stm32_dmamux->dma_reqs[i];
 234                 of_node_put(dma_node);
 235         }
 236
 237         if (dma_req > STM32_DMAMUX_MAX_DMA_REQUESTS) {
 238                 dev_err(&pdev->dev, "Too many DMA Master Requests to manage\n");
 239                 return -ENODEV;
 240         }
 241
 242         stm32_dmamux->dma_requests = dma_req;
 243         stm32_dmamux->dma_reqs[0] = count;
 244         stm32_dmamux->dma_inuse = devm_kcalloc(&pdev->dev,
 245                                                BITS_TO_LONGS(dma_req),
 246                                                sizeof(unsigned long),
 247                                                GFP_KERNEL);
 248         if (!stm32_dmamux->dma_inuse)
 249                 return -ENOMEM;
 250
 251         if (device_property_read_u32(&pdev->dev, "dma-requests",
 252                                      &stm32_dmamux->dmamux_requests)) {
 253                 stm32_dmamux->dmamux_requests = STM32_DMAMUX_MAX_REQUESTS;
 254                 dev_warn(&pdev->dev, "DMAMUX defaulting on %u requests\n",
 255                          stm32_dmamux->dmamux_requests);
 256         }
 257
 258         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 259         iomem = devm_ioremap_resource(&pdev->dev, res);
 260         if (IS_ERR(iomem))
 261                 return PTR_ERR(iomem);
 262
 263         spin_lock_init(&stm32_dmamux->lock);
 264
 265         stm32_dmamux->clk = devm_clk_get(&pdev->dev, NULL);
 266         if (IS_ERR(stm32_dmamux->clk)) {
 267                 ret = PTR_ERR(stm32_dmamux->clk);
 268                 if (ret == -EPROBE_DEFER)
 269                         dev_info(&pdev->dev, "Missing controller clock\n");
 270                 return ret;
 271         }
 272
 273         stm32_dmamux->rst = devm_reset_control_get(&pdev->dev, NULL);
 274         if (!IS_ERR(stm32_dmamux->rst)) {
 275                 reset_control_assert(stm32_dmamux->rst);
 276                 udelay(2);
 277                 reset_control_deassert(stm32_dmamux->rst);
 278         }
 279
 280         stm32_dmamux->iomem = iomem;
 281         stm32_dmamux->dmarouter.dev = &pdev->dev;
 282         stm32_dmamux->dmarouter.route_free = stm32_dmamux_free;
 283
 284         platform_set_drvdata(pdev, stm32_dmamux);
 285
 286         if (!IS_ERR(stm32_dmamux->clk)) {
 287                 ret = clk_prepare_enable(stm32_dmamux->clk);
 288                 if (ret < 0) {
 289                         dev_err(&pdev->dev, "clk_prep_enable error: %d\n", ret);
 290                         return ret;
 291                 }
 292         }
 293
 294         /* Reset the dmamux */
 295         for (i = 0; i < stm32_dmamux->dma_requests; i++)
 296                 stm32_dmamux_write(stm32_dmamux->iomem, STM32_DMAMUX_CCR(i), 0);
 297
 298         if (!IS_ERR(stm32_dmamux->clk))
 299                 clk_disable(stm32_dmamux->clk);
 300
 301         return of_dma_router_register(node, stm32_dmamux_route_allocate,
 302                                      &stm32_dmamux->dmarouter);
 303 }
 304
 305 static const struct of_device_id stm32_dmamux_match[] = {
 306         { .compatible = "st,stm32h7-dmamux" },
 307         {},
 308 };
 309
 310 static struct platform_driver stm32_dmamux_driver = {
 311         .probe  = stm32_dmamux_probe,
 312         .driver = {
 313                 .name = "stm32-dmamux",
 314                 .of_match_table = stm32_dmamux_match,
 315         },
 316 };
 317
 318 static int __init stm32_dmamux_init(void)
 319 {
 320         return platform_driver_register(&stm32_dmamux_driver);
 321 }
 322 arch_initcall(stm32_dmamux_init);
 323
 324 MODULE_DESCRIPTION("DMA Router driver for STM32 DMA MUX");
 325 MODULE_AUTHOR("M'boumba Cedric Madianga <cedric.madianga@gmail.com>");
 326 MODULE_AUTHOR("Pierre-Yves Mordret <pierre-yves.mordret@st.com>");
 327 MODULE_LICENSE("GPL v2");