linux/drivers/acpi/acpi_lpss.c
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   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
  25ACPI_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
  38struct lpss_shared_clock {
  39        const char *name;
  40        unsigned long rate;
  41        struct clk *clk;
  42};
  43
  44struct lpss_private_data;
  45
  46struct 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
  57static struct lpss_device_desc lpss_dma_desc = {
  58        .clk_required = true,
  59        .clkdev_name = "hclk",
  60};
  61
  62struct 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
  69static 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
  78static 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
  85static 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
  93static struct lpss_device_desc lpt_sdio_dev_desc = {
  94        .prv_offset = 0x1000,
  95        .prv_size_override = 0x1018,
  96        .ltr_required = true,
  97};
  98
  99static struct lpss_shared_clock uart_clock = {
 100        .name = "uart_clk",
 101        .rate = 44236800,
 102};
 103
 104static 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
 112static struct lpss_shared_clock spi_clock = {
 113        .name = "spi_clk",
 114        .rate = 50000000,
 115};
 116
 117static 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
 124static struct lpss_device_desc byt_sdio_dev_desc = {
 125        .clk_required = true,
 126};
 127
 128static struct lpss_shared_clock i2c_clock = {
 129        .name = "i2c_clk",
 130        .rate = 100000000,
 131};
 132
 133static struct lpss_device_desc byt_i2c_dev_desc = {
 134        .clk_required = true,
 135        .prv_offset = 0x800,
 136        .shared_clock = &i2c_clock,
 137};
 138
 139static 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
 163static 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. */
 170static struct platform_device *lpss_clk_dev;
 171
 172static inline void lpt_register_clock_device(void)
 173{
 174        lpss_clk_dev = platform_device_register_simple("clk-lpt", -1, NULL, 0);
 175}
 176
 177static 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
 230static 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                        pdata->dev_desc = dev_desc;
 261                        break;
 262                }
 263
 264        acpi_dev_free_resource_list(&resource_list);
 265
 266        if (dev_desc->clk_required) {
 267                ret = register_device_clock(adev, pdata);
 268                if (ret) {
 269                        /* Skip the device, but continue the namespace scan. */
 270                        ret = 0;
 271                        goto err_out;
 272                }
 273        }
 274
 275        /*
 276         * This works around a known issue in ACPI tables where LPSS devices
 277         * have _PS0 and _PS3 without _PSC (and no power resources), so
 278         * acpi_bus_init_power() will assume that the BIOS has put them into D0.
 279         */
 280        ret = acpi_device_fix_up_power(adev);
 281        if (ret) {
 282                /* Skip the device, but continue the namespace scan. */
 283                ret = 0;
 284                goto err_out;
 285        }
 286
 287        if (dev_desc->setup)
 288                dev_desc->setup(pdata);
 289
 290        adev->driver_data = pdata;
 291        ret = acpi_create_platform_device(adev, id);
 292        if (ret > 0)
 293                return ret;
 294
 295        adev->driver_data = NULL;
 296
 297 err_out:
 298        kfree(pdata);
 299        return ret;
 300}
 301
 302static int lpss_reg_read(struct device *dev, unsigned int reg, u32 *val)
 303{
 304        struct acpi_device *adev;
 305        struct lpss_private_data *pdata;
 306        unsigned long flags;
 307        int ret;
 308
 309        ret = acpi_bus_get_device(ACPI_HANDLE(dev), &adev);
 310        if (WARN_ON(ret))
 311                return ret;
 312
 313        spin_lock_irqsave(&dev->power.lock, flags);
 314        if (pm_runtime_suspended(dev)) {
 315                ret = -EAGAIN;
 316                goto out;
 317        }
 318        pdata = acpi_driver_data(adev);
 319        if (WARN_ON(!pdata || !pdata->mmio_base)) {
 320                ret = -ENODEV;
 321                goto out;
 322        }
 323        *val = readl(pdata->mmio_base + pdata->dev_desc->prv_offset + reg);
 324
 325 out:
 326        spin_unlock_irqrestore(&dev->power.lock, flags);
 327        return ret;
 328}
 329
 330static ssize_t lpss_ltr_show(struct device *dev, struct device_attribute *attr,
 331                             char *buf)
 332{
 333        u32 ltr_value = 0;
 334        unsigned int reg;
 335        int ret;
 336
 337        reg = strcmp(attr->attr.name, "auto_ltr") ? LPSS_SW_LTR : LPSS_AUTO_LTR;
 338        ret = lpss_reg_read(dev, reg, &ltr_value);
 339        if (ret)
 340                return ret;
 341
 342        return snprintf(buf, PAGE_SIZE, "%08x\n", ltr_value);
 343}
 344
 345static ssize_t lpss_ltr_mode_show(struct device *dev,
 346                                  struct device_attribute *attr, char *buf)
 347{
 348        u32 ltr_mode = 0;
 349        char *outstr;
 350        int ret;
 351
 352        ret = lpss_reg_read(dev, LPSS_GENERAL, &ltr_mode);
 353        if (ret)
 354                return ret;
 355
 356        outstr = (ltr_mode & LPSS_GENERAL_LTR_MODE_SW) ? "sw" : "auto";
 357        return sprintf(buf, "%s\n", outstr);
 358}
 359
 360static DEVICE_ATTR(auto_ltr, S_IRUSR, lpss_ltr_show, NULL);
 361static DEVICE_ATTR(sw_ltr, S_IRUSR, lpss_ltr_show, NULL);
 362static DEVICE_ATTR(ltr_mode, S_IRUSR, lpss_ltr_mode_show, NULL);
 363
 364static struct attribute *lpss_attrs[] = {
 365        &dev_attr_auto_ltr.attr,
 366        &dev_attr_sw_ltr.attr,
 367        &dev_attr_ltr_mode.attr,
 368        NULL,
 369};
 370
 371static struct attribute_group lpss_attr_group = {
 372        .attrs = lpss_attrs,
 373        .name = "lpss_ltr",
 374};
 375
 376static int acpi_lpss_platform_notify(struct notifier_block *nb,
 377                                     unsigned long action, void *data)
 378{
 379        struct platform_device *pdev = to_platform_device(data);
 380        struct lpss_private_data *pdata;
 381        struct acpi_device *adev;
 382        const struct acpi_device_id *id;
 383        int ret = 0;
 384
 385        id = acpi_match_device(acpi_lpss_device_ids, &pdev->dev);
 386        if (!id || !id->driver_data)
 387                return 0;
 388
 389        if (acpi_bus_get_device(ACPI_HANDLE(&pdev->dev), &adev))
 390                return 0;
 391
 392        pdata = acpi_driver_data(adev);
 393        if (!pdata || !pdata->mmio_base || !pdata->dev_desc->ltr_required)
 394                return 0;
 395
 396        if (pdata->mmio_size < pdata->dev_desc->prv_offset + LPSS_LTR_SIZE) {
 397                dev_err(&pdev->dev, "MMIO size insufficient to access LTR\n");
 398                return 0;
 399        }
 400
 401        if (action == BUS_NOTIFY_ADD_DEVICE)
 402                ret = sysfs_create_group(&pdev->dev.kobj, &lpss_attr_group);
 403        else if (action == BUS_NOTIFY_DEL_DEVICE)
 404                sysfs_remove_group(&pdev->dev.kobj, &lpss_attr_group);
 405
 406        return ret;
 407}
 408
 409static struct notifier_block acpi_lpss_nb = {
 410        .notifier_call = acpi_lpss_platform_notify,
 411};
 412
 413static struct acpi_scan_handler lpss_handler = {
 414        .ids = acpi_lpss_device_ids,
 415        .attach = acpi_lpss_create_device,
 416};
 417
 418void __init acpi_lpss_init(void)
 419{
 420        if (!lpt_clk_init()) {
 421                bus_register_notifier(&platform_bus_type, &acpi_lpss_nb);
 422                acpi_scan_add_handler(&lpss_handler);
 423        }
 424}
 425
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