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_GENERAL_UART_RTS_OVRD      BIT(3)
  34 #define LPSS_SW_LTR                     0x10
  35 #define LPSS_AUTO_LTR                   0x14
  36 #define LPSS_TX_INT                     0x20
  37 #define LPSS_TX_INT_MASK                BIT(1)
  38
  39 struct lpss_shared_clock {
  40         const char *name;
  41         unsigned long rate;
  42         struct clk *clk;
  43 };
  44
  45 struct lpss_private_data;
  46
  47 struct lpss_device_desc {
  48         bool clk_required;
  49         const char *clkdev_name;
  50         bool ltr_required;
  51         unsigned int prv_offset;
  52         size_t prv_size_override;
  53         bool clk_gate;
  54         struct lpss_shared_clock *shared_clock;
  55         void (*setup)(struct lpss_private_data *pdata);
  56 };
  57
  58 static struct lpss_device_desc lpss_dma_desc = {
  59         .clk_required = true,
  60         .clkdev_name = "hclk",
  61 };
  62
  63 struct lpss_private_data {
  64         void __iomem *mmio_base;
  65         resource_size_t mmio_size;
  66         struct clk *clk;
  67         const struct lpss_device_desc *dev_desc;
  68 };
  69
  70 static void lpss_uart_setup(struct lpss_private_data *pdata)
  71 {
  72         unsigned int offset;
  73         u32 reg;
  74
  75         offset = pdata->dev_desc->prv_offset + LPSS_TX_INT;
  76         reg = readl(pdata->mmio_base + offset);
  77         writel(reg | LPSS_TX_INT_MASK, pdata->mmio_base + offset);
  78
  79         offset = pdata->dev_desc->prv_offset + LPSS_GENERAL;
  80         reg = readl(pdata->mmio_base + offset);
  81         writel(reg | LPSS_GENERAL_UART_RTS_OVRD, pdata->mmio_base + offset);
  82 }
  83
  84 static struct lpss_device_desc lpt_dev_desc = {
  85         .clk_required = true,
  86         .prv_offset = 0x800,
  87         .ltr_required = true,
  88         .clk_gate = true,
  89 };
  90
  91 static struct lpss_device_desc lpt_uart_dev_desc = {
  92         .clk_required = true,
  93         .prv_offset = 0x800,
  94         .ltr_required = true,
  95         .clk_gate = true,
  96         .setup = lpss_uart_setup,
  97 };
  98
  99 static struct lpss_device_desc lpt_sdio_dev_desc = {
 100         .prv_offset = 0x1000,
 101         .prv_size_override = 0x1018,
 102         .ltr_required = true,
 103 };
 104
 105 static struct lpss_shared_clock uart_clock = {
 106         .name = "uart_clk",
 107         .rate = 44236800,
 108 };
 109
 110 static struct lpss_device_desc byt_uart_dev_desc = {
 111         .clk_required = true,
 112         .prv_offset = 0x800,
 113         .clk_gate = true,
 114         .shared_clock = &uart_clock,
 115         .setup = lpss_uart_setup,
 116 };
 117
 118 static struct lpss_shared_clock spi_clock = {
 119         .name = "spi_clk",
 120         .rate = 50000000,
 121 };
 122
 123 static struct lpss_device_desc byt_spi_dev_desc = {
 124         .clk_required = true,
 125         .prv_offset = 0x400,
 126         .clk_gate = true,
 127         .shared_clock = &spi_clock,
 128 };
 129
 130 static struct lpss_device_desc byt_sdio_dev_desc = {
 131         .clk_required = true,
 132 };
 133
 134 static struct lpss_shared_clock i2c_clock = {
 135         .name = "i2c_clk",
 136         .rate = 100000000,
 137 };
 138
 139 static struct lpss_device_desc byt_i2c_dev_desc = {
 140         .clk_required = true,
 141         .prv_offset = 0x800,
 142         .shared_clock = &i2c_clock,
 143 };
 144
 145 static const struct acpi_device_id acpi_lpss_device_ids[] = {
 146         /* Generic LPSS devices */
 147         { "INTL9C60", (unsigned long)&lpss_dma_desc },
 148
 149         /* Lynxpoint LPSS devices */
 150         { "INT33C0", (unsigned long)&lpt_dev_desc },
 151         { "INT33C1", (unsigned long)&lpt_dev_desc },
 152         { "INT33C2", (unsigned long)&lpt_dev_desc },
 153         { "INT33C3", (unsigned long)&lpt_dev_desc },
 154         { "INT33C4", (unsigned long)&lpt_uart_dev_desc },
 155         { "INT33C5", (unsigned long)&lpt_uart_dev_desc },
 156         { "INT33C6", (unsigned long)&lpt_sdio_dev_desc },
 157         { "INT33C7", },
 158
 159         /* BayTrail LPSS devices */
 160         { "80860F0A", (unsigned long)&byt_uart_dev_desc },
 161         { "80860F0E", (unsigned long)&byt_spi_dev_desc },
 162         { "80860F14", (unsigned long)&byt_sdio_dev_desc },
 163         { "80860F41", (unsigned long)&byt_i2c_dev_desc },
 164         { "INT33B2", },
 165
 166         { }
 167 };
 168
 169 static int is_memory(struct acpi_resource *res, void *not_used)
 170 {
 171         struct resource r;
 172         return !acpi_dev_resource_memory(res, &r);
 173 }
 174
 175 /* LPSS main clock device. */
 176 static struct platform_device *lpss_clk_dev;
 177
 178 static inline void lpt_register_clock_device(void)
 179 {
 180         lpss_clk_dev = platform_device_register_simple("clk-lpt", -1, NULL, 0);
 181 }
 182
 183 static int register_device_clock(struct acpi_device *adev,
 184                                  struct lpss_private_data *pdata)
 185 {
 186         const struct lpss_device_desc *dev_desc = pdata->dev_desc;
 187         struct lpss_shared_clock *shared_clock = dev_desc->shared_clock;
 188         struct clk *clk = ERR_PTR(-ENODEV);
 189         struct lpss_clk_data *clk_data;
 190         const char *parent;
 191
 192         if (!lpss_clk_dev)
 193                 lpt_register_clock_device();
 194
 195         clk_data = platform_get_drvdata(lpss_clk_dev);
 196         if (!clk_data)
 197                 return -ENODEV;
 198
 199         if (dev_desc->clkdev_name) {
 200                 clk_register_clkdev(clk_data->clk, dev_desc->clkdev_name,
 201                                     dev_name(&adev->dev));
 202                 return 0;
 203         }
 204
 205         if (!pdata->mmio_base
 206             || pdata->mmio_size < dev_desc->prv_offset + LPSS_CLK_SIZE)
 207                 return -ENODATA;
 208
 209         parent = clk_data->name;
 210
 211         if (shared_clock) {
 212                 clk = shared_clock->clk;
 213                 if (!clk) {
 214                         clk = clk_register_fixed_rate(NULL, shared_clock->name,
 215                                                       "lpss_clk", 0,
 216                                                       shared_clock->rate);
 217                         shared_clock->clk = clk;
 218                 }
 219                 parent = shared_clock->name;
 220         }
 221
 222         if (dev_desc->clk_gate) {
 223                 clk = clk_register_gate(NULL, dev_name(&adev->dev), parent, 0,
 224                                         pdata->mmio_base + dev_desc->prv_offset,
 225                                         0, 0, NULL);
 226                 pdata->clk = clk;
 227         }
 228
 229         if (IS_ERR(clk))
 230                 return PTR_ERR(clk);
 231
 232         clk_register_clkdev(clk, NULL, dev_name(&adev->dev));
 233         return 0;
 234 }
 235
 236 static int acpi_lpss_create_device(struct acpi_device *adev,
 237                                    const struct acpi_device_id *id)
 238 {
 239         struct lpss_device_desc *dev_desc;
 240         struct lpss_private_data *pdata;
 241         struct resource_list_entry *rentry;
 242         struct list_head resource_list;
 243         int ret;
 244
 245         dev_desc = (struct lpss_device_desc *)id->driver_data;
 246         if (!dev_desc)
 247                 return acpi_create_platform_device(adev, id);
 248
 249         pdata = kzalloc(sizeof(*pdata), GFP_KERNEL);
 250         if (!pdata)
 251                 return -ENOMEM;
 252
 253         INIT_LIST_HEAD(&resource_list);
 254         ret = acpi_dev_get_resources(adev, &resource_list, is_memory, NULL);
 255         if (ret < 0)
 256                 goto err_out;
 257
 258         list_for_each_entry(rentry, &resource_list, node)
 259                 if (resource_type(&rentry->res) == IORESOURCE_MEM) {
 260                         if (dev_desc->prv_size_override)
 261                                 pdata->mmio_size = dev_desc->prv_size_override;
 262                         else
 263                                 pdata->mmio_size = resource_size(&rentry->res);
 264                         pdata->mmio_base = ioremap(rentry->res.start,
 265                                                    pdata->mmio_size);
 266                         break;
 267                 }
 268
 269         acpi_dev_free_resource_list(&resource_list);
 270
 271         pdata->dev_desc = dev_desc;
 272
 273         if (dev_desc->clk_required) {
 274                 ret = register_device_clock(adev, pdata);
 275                 if (ret) {
 276                         /* Skip the device, but continue the namespace scan. */
 277                         ret = 0;
 278                         goto err_out;
 279                 }
 280         }
 281
 282         /*
 283          * This works around a known issue in ACPI tables where LPSS devices
 284          * have _PS0 and _PS3 without _PSC (and no power resources), so
 285          * acpi_bus_init_power() will assume that the BIOS has put them into D0.
 286          */
 287         ret = acpi_device_fix_up_power(adev);
 288         if (ret) {
 289                 /* Skip the device, but continue the namespace scan. */
 290                 ret = 0;
 291                 goto err_out;
 292         }
 293
 294         if (dev_desc->setup)
 295                 dev_desc->setup(pdata);
 296
 297         adev->driver_data = pdata;
 298         ret = acpi_create_platform_device(adev, id);
 299         if (ret > 0)
 300                 return ret;
 301
 302         adev->driver_data = NULL;
 303
 304  err_out:
 305         kfree(pdata);
 306         return ret;
 307 }
 308
 309 static int lpss_reg_read(struct device *dev, unsigned int reg, u32 *val)
 310 {
 311         struct acpi_device *adev;
 312         struct lpss_private_data *pdata;
 313         unsigned long flags;
 314         int ret;
 315
 316         ret = acpi_bus_get_device(ACPI_HANDLE(dev), &adev);
 317         if (WARN_ON(ret))
 318                 return ret;
 319
 320         spin_lock_irqsave(&dev->power.lock, flags);
 321         if (pm_runtime_suspended(dev)) {
 322                 ret = -EAGAIN;
 323                 goto out;
 324         }
 325         pdata = acpi_driver_data(adev);
 326         if (WARN_ON(!pdata || !pdata->mmio_base)) {
 327                 ret = -ENODEV;
 328                 goto out;
 329         }
 330         *val = readl(pdata->mmio_base + pdata->dev_desc->prv_offset + reg);
 331
 332  out:
 333         spin_unlock_irqrestore(&dev->power.lock, flags);
 334         return ret;
 335 }
 336
 337 static ssize_t lpss_ltr_show(struct device *dev, struct device_attribute *attr,
 338                              char *buf)
 339 {
 340         u32 ltr_value = 0;
 341         unsigned int reg;
 342         int ret;
 343
 344         reg = strcmp(attr->attr.name, "auto_ltr") ? LPSS_SW_LTR : LPSS_AUTO_LTR;
 345         ret = lpss_reg_read(dev, reg, &ltr_value);
 346         if (ret)
 347                 return ret;
 348
 349         return snprintf(buf, PAGE_SIZE, "%08x\n", ltr_value);
 350 }
 351
 352 static ssize_t lpss_ltr_mode_show(struct device *dev,
 353                                   struct device_attribute *attr, char *buf)
 354 {
 355         u32 ltr_mode = 0;
 356         char *outstr;
 357         int ret;
 358
 359         ret = lpss_reg_read(dev, LPSS_GENERAL, &ltr_mode);
 360         if (ret)
 361                 return ret;
 362
 363         outstr = (ltr_mode & LPSS_GENERAL_LTR_MODE_SW) ? "sw" : "auto";
 364         return sprintf(buf, "%s\n", outstr);
 365 }
 366
 367 static DEVICE_ATTR(auto_ltr, S_IRUSR, lpss_ltr_show, NULL);
 368 static DEVICE_ATTR(sw_ltr, S_IRUSR, lpss_ltr_show, NULL);
 369 static DEVICE_ATTR(ltr_mode, S_IRUSR, lpss_ltr_mode_show, NULL);
 370
 371 static struct attribute *lpss_attrs[] = {
 372         &dev_attr_auto_ltr.attr,
 373         &dev_attr_sw_ltr.attr,
 374         &dev_attr_ltr_mode.attr,
 375         NULL,
 376 };
 377
 378 static struct attribute_group lpss_attr_group = {
 379         .attrs = lpss_attrs,
 380         .name = "lpss_ltr",
 381 };
 382
 383 static int acpi_lpss_platform_notify(struct notifier_block *nb,
 384                                      unsigned long action, void *data)
 385 {
 386         struct platform_device *pdev = to_platform_device(data);
 387         struct lpss_private_data *pdata;
 388         struct acpi_device *adev;
 389         const struct acpi_device_id *id;
 390         int ret = 0;
 391
 392         id = acpi_match_device(acpi_lpss_device_ids, &pdev->dev);
 393         if (!id || !id->driver_data)
 394                 return 0;
 395
 396         if (acpi_bus_get_device(ACPI_HANDLE(&pdev->dev), &adev))
 397                 return 0;
 398
 399         pdata = acpi_driver_data(adev);
 400         if (!pdata || !pdata->mmio_base || !pdata->dev_desc->ltr_required)
 401                 return 0;
 402
 403         if (pdata->mmio_size < pdata->dev_desc->prv_offset + LPSS_LTR_SIZE) {
 404                 dev_err(&pdev->dev, "MMIO size insufficient to access LTR\n");
 405                 return 0;
 406         }
 407
 408         if (action == BUS_NOTIFY_ADD_DEVICE)
 409                 ret = sysfs_create_group(&pdev->dev.kobj, &lpss_attr_group);
 410         else if (action == BUS_NOTIFY_DEL_DEVICE)
 411                 sysfs_remove_group(&pdev->dev.kobj, &lpss_attr_group);
 412
 413         return ret;
 414 }
 415
 416 static struct notifier_block acpi_lpss_nb = {
 417         .notifier_call = acpi_lpss_platform_notify,
 418 };
 419
 420 static struct acpi_scan_handler lpss_handler = {
 421         .ids = acpi_lpss_device_ids,
 422         .attach = acpi_lpss_create_device,
 423 };
 424
 425 void __init acpi_lpss_init(void)
 426 {
 427         if (!lpt_clk_init()) {
 428                 bus_register_notifier(&platform_bus_type, &acpi_lpss_nb);
 429                 acpi_scan_add_handler(&lpss_handler);
 430         }
 431 }