drivers/acpi/acpi_lpss.c

   1 /*
   2  * ACPI support for Intel Lynxpoint LPSS.
   3  *
   4  * Copyright (C) 2013, Intel Corporation
   5  * Authors: Mika Westerberg <mika.westerberg@linux.intel.com>
   6  *          Rafael J. Wysocki <rafael.j.wysocki@intel.com>
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 as
  10  * published by the Free Software Foundation.
  11  */
  12
  13 #include <linux/acpi.h>
  14 #include <linux/clk.h>
  15 #include <linux/clkdev.h>
  16 #include <linux/clk-provider.h>
  17 #include <linux/err.h>
  18 #include <linux/io.h>
  19 #include <linux/platform_device.h>
  20 #include <linux/platform_data/clk-lpss.h>
  21 #include <linux/pm_runtime.h>
  22
  23 #include "internal.h"
  24
  25 ACPI_MODULE_NAME("acpi_lpss");
  26
  27 #define LPSS_CLK_SIZE   0x04
  28 #define LPSS_LTR_SIZE   0x18
  29
  30 /* Offsets relative to LPSS_PRIVATE_OFFSET */
  31 #define LPSS_GENERAL                    0x08
  32 #define LPSS_GENERAL_LTR_MODE_SW        BIT(2)
  33 #define LPSS_SW_LTR                     0x10
  34 #define LPSS_AUTO_LTR                   0x14
  35 #define LPSS_TX_INT                     0x20
  36 #define LPSS_TX_INT_MASK                BIT(1)
  37
  38 struct lpss_shared_clock {
  39         const char *name;
  40         unsigned long rate;
  41         struct clk *clk;
  42 };
  43
  44 struct lpss_private_data;
  45
  46 struct lpss_device_desc {
  47         bool clk_required;
  48         const char *clkdev_name;
  49         bool ltr_required;
  50         unsigned int prv_offset;
  51         size_t prv_size_override;
  52         bool clk_gate;
  53         struct lpss_shared_clock *shared_clock;
  54         void (*setup)(struct lpss_private_data *pdata);
  55 };
  56
  57 static struct lpss_device_desc lpss_dma_desc = {
  58         .clk_required = true,
  59         .clkdev_name = "hclk",
  60 };
  61
  62 struct lpss_private_data {
  63         void __iomem *mmio_base;
  64         resource_size_t mmio_size;
  65         struct clk *clk;
  66         const struct lpss_device_desc *dev_desc;
  67 };
  68
  69 static void lpss_uart_setup(struct lpss_private_data *pdata)
  70 {
  71         unsigned int tx_int_offset = pdata->dev_desc->prv_offset + LPSS_TX_INT;
  72         u32 reg;
  73
  74         reg = readl(pdata->mmio_base + tx_int_offset);
  75         writel(reg | LPSS_TX_INT_MASK, pdata->mmio_base + tx_int_offset);
  76 }
  77
  78 static struct lpss_device_desc lpt_dev_desc = {
  79         .clk_required = true,
  80         .prv_offset = 0x800,
  81         .ltr_required = true,
  82         .clk_gate = true,
  83 };
  84
  85 static struct lpss_device_desc lpt_uart_dev_desc = {
  86         .clk_required = true,
  87         .prv_offset = 0x800,
  88         .ltr_required = true,
  89         .clk_gate = true,
  90         .setup = lpss_uart_setup,
  91 };
  92
  93 static struct lpss_device_desc lpt_sdio_dev_desc = {
  94         .prv_offset = 0x1000,
  95         .prv_size_override = 0x1018,
  96         .ltr_required = true,
  97 };
  98
  99 static struct lpss_shared_clock uart_clock = {
 100         .name = "uart_clk",
 101         .rate = 44236800,
 102 };
 103
 104 static struct lpss_device_desc byt_uart_dev_desc = {
 105         .clk_required = true,
 106         .prv_offset = 0x800,
 107         .clk_gate = true,
 108         .shared_clock = &uart_clock,
 109         .setup = lpss_uart_setup,
 110 };
 111
 112 static struct lpss_shared_clock spi_clock = {
 113         .name = "spi_clk",
 114         .rate = 50000000,
 115 };
 116
 117 static struct lpss_device_desc byt_spi_dev_desc = {
 118         .clk_required = true,
 119         .prv_offset = 0x400,
 120         .clk_gate = true,
 121         .shared_clock = &spi_clock,
 122 };
 123
 124 static struct lpss_device_desc byt_sdio_dev_desc = {
 125         .clk_required = true,
 126 };
 127
 128 static struct lpss_shared_clock i2c_clock = {
 129         .name = "i2c_clk",
 130         .rate = 100000000,
 131 };
 132
 133 static struct lpss_device_desc byt_i2c_dev_desc = {
 134         .clk_required = true,
 135         .prv_offset = 0x800,
 136         .shared_clock = &i2c_clock,
 137 };
 138
 139 static const struct acpi_device_id acpi_lpss_device_ids[] = {
 140         /* Generic LPSS devices */
 141         { "INTL9C60", (unsigned long)&lpss_dma_desc },
 142
 143         /* Lynxpoint LPSS devices */
 144         { "INT33C0", (unsigned long)&lpt_dev_desc },
 145         { "INT33C1", (unsigned long)&lpt_dev_desc },
 146         { "INT33C2", (unsigned long)&lpt_dev_desc },
 147         { "INT33C3", (unsigned long)&lpt_dev_desc },
 148         { "INT33C4", (unsigned long)&lpt_uart_dev_desc },
 149         { "INT33C5", (unsigned long)&lpt_uart_dev_desc },
 150         { "INT33C6", (unsigned long)&lpt_sdio_dev_desc },
 151         { "INT33C7", },
 152
 153         /* BayTrail LPSS devices */
 154         { "80860F0A", (unsigned long)&byt_uart_dev_desc },
 155         { "80860F0E", (unsigned long)&byt_spi_dev_desc },
 156         { "80860F14", (unsigned long)&byt_sdio_dev_desc },
 157         { "80860F41", (unsigned long)&byt_i2c_dev_desc },
 158         { "INT33B2", },
 159
 160         { }
 161 };
 162
 163 static int is_memory(struct acpi_resource *res, void *not_used)
 164 {
 165         struct resource r;
 166         return !acpi_dev_resource_memory(res, &r);
 167 }
 168
 169 /* LPSS main clock device. */
 170 static struct platform_device *lpss_clk_dev;
 171
 172 static inline void lpt_register_clock_device(void)
 173 {
 174         lpss_clk_dev = platform_device_register_simple("clk-lpt", -1, NULL, 0);
 175 }
 176
 177 static int register_device_clock(struct acpi_device *adev,
 178                                  struct lpss_private_data *pdata)
 179 {
 180         const struct lpss_device_desc *dev_desc = pdata->dev_desc;
 181         struct lpss_shared_clock *shared_clock = dev_desc->shared_clock;
 182         struct clk *clk = ERR_PTR(-ENODEV);
 183         struct lpss_clk_data *clk_data;
 184         const char *parent;
 185
 186         if (!lpss_clk_dev)
 187                 lpt_register_clock_device();
 188
 189         clk_data = platform_get_drvdata(lpss_clk_dev);
 190         if (!clk_data)
 191                 return -ENODEV;
 192
 193         if (dev_desc->clkdev_name) {
 194                 clk_register_clkdev(clk_data->clk, dev_desc->clkdev_name,
 195                                     dev_name(&adev->dev));
 196                 return 0;
 197         }
 198
 199         if (!pdata->mmio_base
 200             || pdata->mmio_size < dev_desc->prv_offset + LPSS_CLK_SIZE)
 201                 return -ENODATA;
 202
 203         parent = clk_data->name;
 204
 205         if (shared_clock) {
 206                 clk = shared_clock->clk;
 207                 if (!clk) {
 208                         clk = clk_register_fixed_rate(NULL, shared_clock->name,
 209                                                       "lpss_clk", 0,
 210                                                       shared_clock->rate);
 211                         shared_clock->clk = clk;
 212                 }
 213                 parent = shared_clock->name;
 214         }
 215
 216         if (dev_desc->clk_gate) {
 217                 clk = clk_register_gate(NULL, dev_name(&adev->dev), parent, 0,
 218                                         pdata->mmio_base + dev_desc->prv_offset,
 219                                         0, 0, NULL);
 220                 pdata->clk = clk;
 221         }
 222
 223         if (IS_ERR(clk))
 224                 return PTR_ERR(clk);
 225
 226         clk_register_clkdev(clk, NULL, dev_name(&adev->dev));
 227         return 0;
 228 }
 229
 230 static int acpi_lpss_create_device(struct acpi_device *adev,
 231                                    const struct acpi_device_id *id)
 232 {
 233         struct lpss_device_desc *dev_desc;
 234         struct lpss_private_data *pdata;
 235         struct resource_list_entry *rentry;
 236         struct list_head resource_list;
 237         int ret;
 238
 239         dev_desc = (struct lpss_device_desc *)id->driver_data;
 240         if (!dev_desc)
 241                 return acpi_create_platform_device(adev, id);
 242
 243         pdata = kzalloc(sizeof(*pdata), GFP_KERNEL);
 244         if (!pdata)
 245                 return -ENOMEM;
 246
 247         INIT_LIST_HEAD(&resource_list);
 248         ret = acpi_dev_get_resources(adev, &resource_list, is_memory, NULL);
 249         if (ret < 0)
 250                 goto err_out;
 251
 252         list_for_each_entry(rentry, &resource_list, node)
 253                 if (resource_type(&rentry->res) == IORESOURCE_MEM) {
 254                         if (dev_desc->prv_size_override)
 255                                 pdata->mmio_size = dev_desc->prv_size_override;
 256                         else
 257                                 pdata->mmio_size = resource_size(&rentry->res);
 258                         pdata->mmio_base = ioremap(rentry->res.start,
 259                                                    pdata->mmio_size);
 260                         break;
 261                 }
 262
 263         acpi_dev_free_resource_list(&resource_list);
 264
 265         pdata->dev_desc = dev_desc;
 266
 267         if (dev_desc->clk_required) {
 268                 ret = register_device_clock(adev, pdata);
 269                 if (ret) {
 270                         /* Skip the device, but continue the namespace scan. */
 271                         ret = 0;
 272                         goto err_out;
 273                 }
 274         }
 275
 276         /*
 277          * This works around a known issue in ACPI tables where LPSS devices
 278          * have _PS0 and _PS3 without _PSC (and no power resources), so
 279          * acpi_bus_init_power() will assume that the BIOS has put them into D0.
 280          */
 281         ret = acpi_device_fix_up_power(adev);
 282         if (ret) {
 283                 /* Skip the device, but continue the namespace scan. */
 284                 ret = 0;
 285                 goto err_out;
 286         }
 287
 288         if (dev_desc->setup)
 289                 dev_desc->setup(pdata);
 290
 291         adev->driver_data = pdata;
 292         ret = acpi_create_platform_device(adev, id);
 293         if (ret > 0)
 294                 return ret;
 295
 296         adev->driver_data = NULL;
 297
 298  err_out:
 299         kfree(pdata);
 300         return ret;
 301 }
 302
 303 static int lpss_reg_read(struct device *dev, unsigned int reg, u32 *val)
 304 {
 305         struct acpi_device *adev;
 306         struct lpss_private_data *pdata;
 307         unsigned long flags;
 308         int ret;
 309
 310         ret = acpi_bus_get_device(ACPI_HANDLE(dev), &adev);
 311         if (WARN_ON(ret))
 312                 return ret;
 313
 314         spin_lock_irqsave(&dev->power.lock, flags);
 315         if (pm_runtime_suspended(dev)) {
 316                 ret = -EAGAIN;
 317                 goto out;
 318         }
 319         pdata = acpi_driver_data(adev);
 320         if (WARN_ON(!pdata || !pdata->mmio_base)) {
 321                 ret = -ENODEV;
 322                 goto out;
 323         }
 324         *val = readl(pdata->mmio_base + pdata->dev_desc->prv_offset + reg);
 325
 326  out:
 327         spin_unlock_irqrestore(&dev->power.lock, flags);
 328         return ret;
 329 }
 330
 331 static ssize_t lpss_ltr_show(struct device *dev, struct device_attribute *attr,
 332                              char *buf)
 333 {
 334         u32 ltr_value = 0;
 335         unsigned int reg;
 336         int ret;
 337
 338         reg = strcmp(attr->attr.name, "auto_ltr") ? LPSS_SW_LTR : LPSS_AUTO_LTR;
 339         ret = lpss_reg_read(dev, reg, &ltr_value);
 340         if (ret)
 341                 return ret;
 342
 343         return snprintf(buf, PAGE_SIZE, "%08x\n", ltr_value);
 344 }
 345
 346 static ssize_t lpss_ltr_mode_show(struct device *dev,
 347                                   struct device_attribute *attr, char *buf)
 348 {
 349         u32 ltr_mode = 0;
 350         char *outstr;
 351         int ret;
 352
 353         ret = lpss_reg_read(dev, LPSS_GENERAL, &ltr_mode);
 354         if (ret)
 355                 return ret;
 356
 357         outstr = (ltr_mode & LPSS_GENERAL_LTR_MODE_SW) ? "sw" : "auto";
 358         return sprintf(buf, "%s\n", outstr);
 359 }
 360
 361 static DEVICE_ATTR(auto_ltr, S_IRUSR, lpss_ltr_show, NULL);
 362 static DEVICE_ATTR(sw_ltr, S_IRUSR, lpss_ltr_show, NULL);
 363 static DEVICE_ATTR(ltr_mode, S_IRUSR, lpss_ltr_mode_show, NULL);
 364
 365 static struct attribute *lpss_attrs[] = {
 366         &dev_attr_auto_ltr.attr,
 367         &dev_attr_sw_ltr.attr,
 368         &dev_attr_ltr_mode.attr,
 369         NULL,
 370 };
 371
 372 static struct attribute_group lpss_attr_group = {
 373         .attrs = lpss_attrs,
 374         .name = "lpss_ltr",
 375 };
 376
 377 static int acpi_lpss_platform_notify(struct notifier_block *nb,
 378                                      unsigned long action, void *data)
 379 {
 380         struct platform_device *pdev = to_platform_device(data);
 381         struct lpss_private_data *pdata;
 382         struct acpi_device *adev;
 383         const struct acpi_device_id *id;
 384         int ret = 0;
 385
 386         id = acpi_match_device(acpi_lpss_device_ids, &pdev->dev);
 387         if (!id || !id->driver_data)
 388                 return 0;
 389
 390         if (acpi_bus_get_device(ACPI_HANDLE(&pdev->dev), &adev))
 391                 return 0;
 392
 393         pdata = acpi_driver_data(adev);
 394         if (!pdata || !pdata->mmio_base || !pdata->dev_desc->ltr_required)
 395                 return 0;
 396
 397         if (pdata->mmio_size < pdata->dev_desc->prv_offset + LPSS_LTR_SIZE) {
 398                 dev_err(&pdev->dev, "MMIO size insufficient to access LTR\n");
 399                 return 0;
 400         }
 401
 402         if (action == BUS_NOTIFY_ADD_DEVICE)
 403                 ret = sysfs_create_group(&pdev->dev.kobj, &lpss_attr_group);
 404         else if (action == BUS_NOTIFY_DEL_DEVICE)
 405                 sysfs_remove_group(&pdev->dev.kobj, &lpss_attr_group);
 406
 407         return ret;
 408 }
 409
 410 static struct notifier_block acpi_lpss_nb = {
 411         .notifier_call = acpi_lpss_platform_notify,
 412 };
 413
 414 static struct acpi_scan_handler lpss_handler = {
 415         .ids = acpi_lpss_device_ids,
 416         .attach = acpi_lpss_create_device,
 417 };
 418
 419 void __init acpi_lpss_init(void)
 420 {
 421         if (!lpt_clk_init()) {
 422                 bus_register_notifier(&platform_bus_type, &acpi_lpss_nb);
 423                 acpi_scan_add_handler(&lpss_handler);
 424         }
 425 }