drivers/clk/x86/clk-pmc-atom.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Intel Atom platform clocks driver for BayTrail and CherryTrail SoCs
   4  *
   5  * Copyright (C) 2016, Intel Corporation
   6  * Author: Irina Tirdea <irina.tirdea@intel.com>
   7  */
   8
   9 #include <linux/clk-provider.h>
  10 #include <linux/clkdev.h>
  11 #include <linux/err.h>
  12 #include <linux/io.h>
  13 #include <linux/platform_data/x86/clk-pmc-atom.h>
  14 #include <linux/platform_device.h>
  15 #include <linux/slab.h>
  16
  17 #define PLT_CLK_NAME_BASE       "pmc_plt_clk"
  18
  19 #define PMC_CLK_CTL_OFFSET              0x60
  20 #define PMC_CLK_CTL_SIZE                4
  21 #define PMC_CLK_NUM                     6
  22 #define PMC_CLK_CTL_GATED_ON_D3         0x0
  23 #define PMC_CLK_CTL_FORCE_ON            0x1
  24 #define PMC_CLK_CTL_FORCE_OFF           0x2
  25 #define PMC_CLK_CTL_RESERVED            0x3
  26 #define PMC_MASK_CLK_CTL                GENMASK(1, 0)
  27 #define PMC_MASK_CLK_FREQ               BIT(2)
  28 #define PMC_CLK_FREQ_XTAL               (0 << 2)        /* 25 MHz */
  29 #define PMC_CLK_FREQ_PLL                (1 << 2)        /* 19.2 MHz */
  30
  31 struct clk_plt_fixed {
  32         struct clk_hw *clk;
  33         struct clk_lookup *lookup;
  34 };
  35
  36 struct clk_plt {
  37         struct clk_hw hw;
  38         void __iomem *reg;
  39         struct clk_lookup *lookup;
  40         /* protect access to PMC registers */
  41         spinlock_t lock;
  42 };
  43
  44 #define to_clk_plt(_hw) container_of(_hw, struct clk_plt, hw)
  45
  46 struct clk_plt_data {
  47         struct clk_plt_fixed **parents;
  48         u8 nparents;
  49         struct clk_plt *clks[PMC_CLK_NUM];
  50         struct clk_lookup *mclk_lookup;
  51         struct clk_lookup *ether_clk_lookup;
  52 };
  53
  54 /* Return an index in parent table */
  55 static inline int plt_reg_to_parent(int reg)
  56 {
  57         switch (reg & PMC_MASK_CLK_FREQ) {
  58         default:
  59         case PMC_CLK_FREQ_XTAL:
  60                 return 0;
  61         case PMC_CLK_FREQ_PLL:
  62                 return 1;
  63         }
  64 }
  65
  66 /* Return clk index of parent */
  67 static inline int plt_parent_to_reg(int index)
  68 {
  69         switch (index) {
  70         default:
  71         case 0:
  72                 return PMC_CLK_FREQ_XTAL;
  73         case 1:
  74                 return PMC_CLK_FREQ_PLL;
  75         }
  76 }
  77
  78 /* Abstract status in simpler enabled/disabled value */
  79 static inline int plt_reg_to_enabled(int reg)
  80 {
  81         switch (reg & PMC_MASK_CLK_CTL) {
  82         case PMC_CLK_CTL_GATED_ON_D3:
  83         case PMC_CLK_CTL_FORCE_ON:
  84                 return 1;       /* enabled */
  85         case PMC_CLK_CTL_FORCE_OFF:
  86         case PMC_CLK_CTL_RESERVED:
  87         default:
  88                 return 0;       /* disabled */
  89         }
  90 }
  91
  92 static void plt_clk_reg_update(struct clk_plt *clk, u32 mask, u32 val)
  93 {
  94         u32 tmp;
  95         unsigned long flags;
  96
  97         spin_lock_irqsave(&clk->lock, flags);
  98
  99         tmp = readl(clk->reg);
 100         tmp = (tmp & ~mask) | (val & mask);
 101         writel(tmp, clk->reg);
 102
 103         spin_unlock_irqrestore(&clk->lock, flags);
 104 }
 105
 106 static int plt_clk_set_parent(struct clk_hw *hw, u8 index)
 107 {
 108         struct clk_plt *clk = to_clk_plt(hw);
 109
 110         plt_clk_reg_update(clk, PMC_MASK_CLK_FREQ, plt_parent_to_reg(index));
 111
 112         return 0;
 113 }
 114
 115 static u8 plt_clk_get_parent(struct clk_hw *hw)
 116 {
 117         struct clk_plt *clk = to_clk_plt(hw);
 118         u32 value;
 119
 120         value = readl(clk->reg);
 121
 122         return plt_reg_to_parent(value);
 123 }
 124
 125 static int plt_clk_enable(struct clk_hw *hw)
 126 {
 127         struct clk_plt *clk = to_clk_plt(hw);
 128
 129         plt_clk_reg_update(clk, PMC_MASK_CLK_CTL, PMC_CLK_CTL_FORCE_ON);
 130
 131         return 0;
 132 }
 133
 134 static void plt_clk_disable(struct clk_hw *hw)
 135 {
 136         struct clk_plt *clk = to_clk_plt(hw);
 137
 138         plt_clk_reg_update(clk, PMC_MASK_CLK_CTL, PMC_CLK_CTL_FORCE_OFF);
 139 }
 140
 141 static int plt_clk_is_enabled(struct clk_hw *hw)
 142 {
 143         struct clk_plt *clk = to_clk_plt(hw);
 144         u32 value;
 145
 146         value = readl(clk->reg);
 147
 148         return plt_reg_to_enabled(value);
 149 }
 150
 151 static const struct clk_ops plt_clk_ops = {
 152         .enable = plt_clk_enable,
 153         .disable = plt_clk_disable,
 154         .is_enabled = plt_clk_is_enabled,
 155         .get_parent = plt_clk_get_parent,
 156         .set_parent = plt_clk_set_parent,
 157         .determine_rate = __clk_mux_determine_rate,
 158 };
 159
 160 static struct clk_plt *plt_clk_register(struct platform_device *pdev, int id,
 161                                         const struct pmc_clk_data *pmc_data,
 162                                         const char **parent_names,
 163                                         int num_parents)
 164 {
 165         struct clk_plt *pclk;
 166         struct clk_init_data init;
 167         int ret;
 168
 169         pclk = devm_kzalloc(&pdev->dev, sizeof(*pclk), GFP_KERNEL);
 170         if (!pclk)
 171                 return ERR_PTR(-ENOMEM);
 172
 173         init.name =  kasprintf(GFP_KERNEL, "%s_%d", PLT_CLK_NAME_BASE, id);
 174         init.ops = &plt_clk_ops;
 175         init.flags = 0;
 176         init.parent_names = parent_names;
 177         init.num_parents = num_parents;
 178
 179         pclk->hw.init = &init;
 180         pclk->reg = pmc_data->base + PMC_CLK_CTL_OFFSET + id * PMC_CLK_CTL_SIZE;
 181         spin_lock_init(&pclk->lock);
 182
 183         /*
 184          * On some systems, the pmc_plt_clocks already enabled by the
 185          * firmware are being marked as critical to avoid them being
 186          * gated by the clock framework.
 187          */
 188         if (pmc_data->critical && plt_clk_is_enabled(&pclk->hw))
 189                 init.flags |= CLK_IS_CRITICAL;
 190
 191         ret = devm_clk_hw_register(&pdev->dev, &pclk->hw);
 192         if (ret) {
 193                 pclk = ERR_PTR(ret);
 194                 goto err_free_init;
 195         }
 196
 197         pclk->lookup = clkdev_hw_create(&pclk->hw, init.name, NULL);
 198         if (!pclk->lookup) {
 199                 pclk = ERR_PTR(-ENOMEM);
 200                 goto err_free_init;
 201         }
 202
 203 err_free_init:
 204         kfree(init.name);
 205         return pclk;
 206 }
 207
 208 static void plt_clk_unregister(struct clk_plt *pclk)
 209 {
 210         clkdev_drop(pclk->lookup);
 211 }
 212
 213 static struct clk_plt_fixed *plt_clk_register_fixed_rate(struct platform_device *pdev,
 214                                                  const char *name,
 215                                                  const char *parent_name,
 216                                                  unsigned long fixed_rate)
 217 {
 218         struct clk_plt_fixed *pclk;
 219
 220         pclk = devm_kzalloc(&pdev->dev, sizeof(*pclk), GFP_KERNEL);
 221         if (!pclk)
 222                 return ERR_PTR(-ENOMEM);
 223
 224         pclk->clk = clk_hw_register_fixed_rate(&pdev->dev, name, parent_name,
 225                                                0, fixed_rate);
 226         if (IS_ERR(pclk->clk))
 227                 return ERR_CAST(pclk->clk);
 228
 229         pclk->lookup = clkdev_hw_create(pclk->clk, name, NULL);
 230         if (!pclk->lookup) {
 231                 clk_hw_unregister_fixed_rate(pclk->clk);
 232                 return ERR_PTR(-ENOMEM);
 233         }
 234
 235         return pclk;
 236 }
 237
 238 static void plt_clk_unregister_fixed_rate(struct clk_plt_fixed *pclk)
 239 {
 240         clkdev_drop(pclk->lookup);
 241         clk_hw_unregister_fixed_rate(pclk->clk);
 242 }
 243
 244 static void plt_clk_unregister_fixed_rate_loop(struct clk_plt_data *data,
 245                                                unsigned int i)
 246 {
 247         while (i--)
 248                 plt_clk_unregister_fixed_rate(data->parents[i]);
 249 }
 250
 251 static void plt_clk_free_parent_names_loop(const char **parent_names,
 252                                            unsigned int i)
 253 {
 254         while (i--)
 255                 kfree_const(parent_names[i]);
 256         kfree(parent_names);
 257 }
 258
 259 static void plt_clk_unregister_loop(struct clk_plt_data *data,
 260                                     unsigned int i)
 261 {
 262         while (i--)
 263                 plt_clk_unregister(data->clks[i]);
 264 }
 265
 266 static const char **plt_clk_register_parents(struct platform_device *pdev,
 267                                              struct clk_plt_data *data,
 268                                              const struct pmc_clk *clks)
 269 {
 270         const char **parent_names;
 271         unsigned int i;
 272         int err;
 273         int nparents = 0;
 274
 275         data->nparents = 0;
 276         while (clks[nparents].name)
 277                 nparents++;
 278
 279         data->parents = devm_kcalloc(&pdev->dev, nparents,
 280                                      sizeof(*data->parents), GFP_KERNEL);
 281         if (!data->parents)
 282                 return ERR_PTR(-ENOMEM);
 283
 284         parent_names = kcalloc(nparents, sizeof(*parent_names),
 285                                GFP_KERNEL);
 286         if (!parent_names)
 287                 return ERR_PTR(-ENOMEM);
 288
 289         for (i = 0; i < nparents; i++) {
 290                 data->parents[i] =
 291                         plt_clk_register_fixed_rate(pdev, clks[i].name,
 292                                                     clks[i].parent_name,
 293                                                     clks[i].freq);
 294                 if (IS_ERR(data->parents[i])) {
 295                         err = PTR_ERR(data->parents[i]);
 296                         goto err_unreg;
 297                 }
 298                 parent_names[i] = kstrdup_const(clks[i].name, GFP_KERNEL);
 299         }
 300
 301         data->nparents = nparents;
 302         return parent_names;
 303
 304 err_unreg:
 305         plt_clk_unregister_fixed_rate_loop(data, i);
 306         plt_clk_free_parent_names_loop(parent_names, i);
 307         return ERR_PTR(err);
 308 }
 309
 310 static void plt_clk_unregister_parents(struct clk_plt_data *data)
 311 {
 312         plt_clk_unregister_fixed_rate_loop(data, data->nparents);
 313 }
 314
 315 static int plt_clk_probe(struct platform_device *pdev)
 316 {
 317         const struct pmc_clk_data *pmc_data;
 318         const char **parent_names;
 319         struct clk_plt_data *data;
 320         unsigned int i;
 321         int err;
 322
 323         pmc_data = dev_get_platdata(&pdev->dev);
 324         if (!pmc_data || !pmc_data->clks)
 325                 return -EINVAL;
 326
 327         data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
 328         if (!data)
 329                 return -ENOMEM;
 330
 331         parent_names = plt_clk_register_parents(pdev, data, pmc_data->clks);
 332         if (IS_ERR(parent_names))
 333                 return PTR_ERR(parent_names);
 334
 335         for (i = 0; i < PMC_CLK_NUM; i++) {
 336                 data->clks[i] = plt_clk_register(pdev, i, pmc_data,
 337                                                  parent_names, data->nparents);
 338                 if (IS_ERR(data->clks[i])) {
 339                         err = PTR_ERR(data->clks[i]);
 340                         goto err_unreg_clk_plt;
 341                 }
 342         }
 343         data->mclk_lookup = clkdev_hw_create(&data->clks[3]->hw, "mclk", NULL);
 344         if (!data->mclk_lookup) {
 345                 err = -ENOMEM;
 346                 goto err_unreg_clk_plt;
 347         }
 348
 349         data->ether_clk_lookup = clkdev_hw_create(&data->clks[4]->hw,
 350                                                   "ether_clk", NULL);
 351         if (!data->ether_clk_lookup) {
 352                 err = -ENOMEM;
 353                 goto err_drop_mclk;
 354         }
 355
 356         plt_clk_free_parent_names_loop(parent_names, data->nparents);
 357
 358         platform_set_drvdata(pdev, data);
 359         return 0;
 360
 361 err_drop_mclk:
 362         clkdev_drop(data->mclk_lookup);
 363 err_unreg_clk_plt:
 364         plt_clk_unregister_loop(data, i);
 365         plt_clk_unregister_parents(data);
 366         plt_clk_free_parent_names_loop(parent_names, data->nparents);
 367         return err;
 368 }
 369
 370 static int plt_clk_remove(struct platform_device *pdev)
 371 {
 372         struct clk_plt_data *data;
 373
 374         data = platform_get_drvdata(pdev);
 375
 376         clkdev_drop(data->ether_clk_lookup);
 377         clkdev_drop(data->mclk_lookup);
 378         plt_clk_unregister_loop(data, PMC_CLK_NUM);
 379         plt_clk_unregister_parents(data);
 380         return 0;
 381 }
 382
 383 static struct platform_driver plt_clk_driver = {
 384         .driver = {
 385                 .name = "clk-pmc-atom",
 386         },
 387         .probe = plt_clk_probe,
 388         .remove = plt_clk_remove,
 389 };
 390 builtin_platform_driver(plt_clk_driver);