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
  36struct lpss_device_desc {
  37        bool clk_required;
  38        const char *clkdev_name;
  39        bool ltr_required;
  40        unsigned int prv_offset;
  41};
  42
  43static struct lpss_device_desc lpss_dma_desc = {
  44        .clk_required = true,
  45        .clkdev_name = "hclk",
  46};
  47
  48struct lpss_private_data {
  49        void __iomem *mmio_base;
  50        resource_size_t mmio_size;
  51        struct clk *clk;
  52        const struct lpss_device_desc *dev_desc;
  53};
  54
  55static struct lpss_device_desc lpt_dev_desc = {
  56        .clk_required = true,
  57        .prv_offset = 0x800,
  58        .ltr_required = true,
  59};
  60
  61static struct lpss_device_desc lpt_sdio_dev_desc = {
  62        .prv_offset = 0x1000,
  63        .ltr_required = true,
  64};
  65
  66static const struct acpi_device_id acpi_lpss_device_ids[] = {
  67        /* Generic LPSS devices */
  68        { "INTL9C60", (unsigned long)&lpss_dma_desc },
  69
  70        /* Lynxpoint LPSS devices */
  71        { "INT33C0", (unsigned long)&lpt_dev_desc },
  72        { "INT33C1", (unsigned long)&lpt_dev_desc },
  73        { "INT33C2", (unsigned long)&lpt_dev_desc },
  74        { "INT33C3", (unsigned long)&lpt_dev_desc },
  75        { "INT33C4", (unsigned long)&lpt_dev_desc },
  76        { "INT33C5", (unsigned long)&lpt_dev_desc },
  77        { "INT33C6", (unsigned long)&lpt_sdio_dev_desc },
  78        { "INT33C7", },
  79
  80        { }
  81};
  82
  83static int is_memory(struct acpi_resource *res, void *not_used)
  84{
  85        struct resource r;
  86        return !acpi_dev_resource_memory(res, &r);
  87}
  88
  89/* LPSS main clock device. */
  90static struct platform_device *lpss_clk_dev;
  91
  92static inline void lpt_register_clock_device(void)
  93{
  94        lpss_clk_dev = platform_device_register_simple("clk-lpt", -1, NULL, 0);
  95}
  96
  97static int register_device_clock(struct acpi_device *adev,
  98                                 struct lpss_private_data *pdata)
  99{
 100        const struct lpss_device_desc *dev_desc = pdata->dev_desc;
 101        struct lpss_clk_data *clk_data;
 102
 103        if (!lpss_clk_dev)
 104                lpt_register_clock_device();
 105
 106        clk_data = platform_get_drvdata(lpss_clk_dev);
 107        if (!clk_data)
 108                return -ENODEV;
 109
 110        if (dev_desc->clkdev_name) {
 111                clk_register_clkdev(clk_data->clk, dev_desc->clkdev_name,
 112                                    dev_name(&adev->dev));
 113                return 0;
 114        }
 115
 116        if (!pdata->mmio_base
 117            || pdata->mmio_size < dev_desc->prv_offset + LPSS_CLK_SIZE)
 118                return -ENODATA;
 119
 120        pdata->clk = clk_register_gate(NULL, dev_name(&adev->dev),
 121                                       clk_data->name, 0,
 122                                       pdata->mmio_base + dev_desc->prv_offset,
 123                                       0, 0, NULL);
 124        if (IS_ERR(pdata->clk))
 125                return PTR_ERR(pdata->clk);
 126
 127        clk_register_clkdev(pdata->clk, NULL, dev_name(&adev->dev));
 128        return 0;
 129}
 130
 131static int acpi_lpss_create_device(struct acpi_device *adev,
 132                                   const struct acpi_device_id *id)
 133{
 134        struct lpss_device_desc *dev_desc;
 135        struct lpss_private_data *pdata;
 136        struct resource_list_entry *rentry;
 137        struct list_head resource_list;
 138        int ret;
 139
 140        dev_desc = (struct lpss_device_desc *)id->driver_data;
 141        if (!dev_desc)
 142                return acpi_create_platform_device(adev, id);
 143
 144        pdata = kzalloc(sizeof(*pdata), GFP_KERNEL);
 145        if (!pdata)
 146                return -ENOMEM;
 147
 148        INIT_LIST_HEAD(&resource_list);
 149        ret = acpi_dev_get_resources(adev, &resource_list, is_memory, NULL);
 150        if (ret < 0)
 151                goto err_out;
 152
 153        list_for_each_entry(rentry, &resource_list, node)
 154                if (resource_type(&rentry->res) == IORESOURCE_MEM) {
 155                        pdata->mmio_size = resource_size(&rentry->res);
 156                        pdata->mmio_base = ioremap(rentry->res.start,
 157                                                   pdata->mmio_size);
 158                        pdata->dev_desc = dev_desc;
 159                        break;
 160                }
 161
 162        acpi_dev_free_resource_list(&resource_list);
 163
 164        if (dev_desc->clk_required) {
 165                ret = register_device_clock(adev, pdata);
 166                if (ret) {
 167                        /* Skip the device, but continue the namespace scan. */
 168                        ret = 0;
 169                        goto err_out;
 170                }
 171        }
 172
 173        /*
 174         * This works around a known issue in ACPI tables where LPSS devices
 175         * have _PS0 and _PS3 without _PSC (and no power resources), so
 176         * acpi_bus_init_power() will assume that the BIOS has put them into D0.
 177         */
 178        ret = acpi_device_fix_up_power(adev);
 179        if (ret) {
 180                /* Skip the device, but continue the namespace scan. */
 181                ret = 0;
 182                goto err_out;
 183        }
 184
 185        adev->driver_data = pdata;
 186        ret = acpi_create_platform_device(adev, id);
 187        if (ret > 0)
 188                return ret;
 189
 190        adev->driver_data = NULL;
 191
 192 err_out:
 193        kfree(pdata);
 194        return ret;
 195}
 196
 197static int lpss_reg_read(struct device *dev, unsigned int reg, u32 *val)
 198{
 199        struct acpi_device *adev;
 200        struct lpss_private_data *pdata;
 201        unsigned long flags;
 202        int ret;
 203
 204        ret = acpi_bus_get_device(ACPI_HANDLE(dev), &adev);
 205        if (WARN_ON(ret))
 206                return ret;
 207
 208        spin_lock_irqsave(&dev->power.lock, flags);
 209        if (pm_runtime_suspended(dev)) {
 210                ret = -EAGAIN;
 211                goto out;
 212        }
 213        pdata = acpi_driver_data(adev);
 214        if (WARN_ON(!pdata || !pdata->mmio_base)) {
 215                ret = -ENODEV;
 216                goto out;
 217        }
 218        *val = readl(pdata->mmio_base + pdata->dev_desc->prv_offset + reg);
 219
 220 out:
 221        spin_unlock_irqrestore(&dev->power.lock, flags);
 222        return ret;
 223}
 224
 225static ssize_t lpss_ltr_show(struct device *dev, struct device_attribute *attr,
 226                             char *buf)
 227{
 228        u32 ltr_value = 0;
 229        unsigned int reg;
 230        int ret;
 231
 232        reg = strcmp(attr->attr.name, "auto_ltr") ? LPSS_SW_LTR : LPSS_AUTO_LTR;
 233        ret = lpss_reg_read(dev, reg, &ltr_value);
 234        if (ret)
 235                return ret;
 236
 237        return snprintf(buf, PAGE_SIZE, "%08x\n", ltr_value);
 238}
 239
 240static ssize_t lpss_ltr_mode_show(struct device *dev,
 241                                  struct device_attribute *attr, char *buf)
 242{
 243        u32 ltr_mode = 0;
 244        char *outstr;
 245        int ret;
 246
 247        ret = lpss_reg_read(dev, LPSS_GENERAL, &ltr_mode);
 248        if (ret)
 249                return ret;
 250
 251        outstr = (ltr_mode & LPSS_GENERAL_LTR_MODE_SW) ? "sw" : "auto";
 252        return sprintf(buf, "%s\n", outstr);
 253}
 254
 255static DEVICE_ATTR(auto_ltr, S_IRUSR, lpss_ltr_show, NULL);
 256static DEVICE_ATTR(sw_ltr, S_IRUSR, lpss_ltr_show, NULL);
 257static DEVICE_ATTR(ltr_mode, S_IRUSR, lpss_ltr_mode_show, NULL);
 258
 259static struct attribute *lpss_attrs[] = {
 260        &dev_attr_auto_ltr.attr,
 261        &dev_attr_sw_ltr.attr,
 262        &dev_attr_ltr_mode.attr,
 263        NULL,
 264};
 265
 266static struct attribute_group lpss_attr_group = {
 267        .attrs = lpss_attrs,
 268        .name = "lpss_ltr",
 269};
 270
 271static int acpi_lpss_platform_notify(struct notifier_block *nb,
 272                                     unsigned long action, void *data)
 273{
 274        struct platform_device *pdev = to_platform_device(data);
 275        struct lpss_private_data *pdata;
 276        struct acpi_device *adev;
 277        const struct acpi_device_id *id;
 278        int ret = 0;
 279
 280        id = acpi_match_device(acpi_lpss_device_ids, &pdev->dev);
 281        if (!id || !id->driver_data)
 282                return 0;
 283
 284        if (acpi_bus_get_device(ACPI_HANDLE(&pdev->dev), &adev))
 285                return 0;
 286
 287        pdata = acpi_driver_data(adev);
 288        if (!pdata || !pdata->mmio_base || !pdata->dev_desc->ltr_required)
 289                return 0;
 290
 291        if (pdata->mmio_size < pdata->dev_desc->prv_offset + LPSS_LTR_SIZE) {
 292                dev_err(&pdev->dev, "MMIO size insufficient to access LTR\n");
 293                return 0;
 294        }
 295
 296        if (action == BUS_NOTIFY_ADD_DEVICE)
 297                ret = sysfs_create_group(&pdev->dev.kobj, &lpss_attr_group);
 298        else if (action == BUS_NOTIFY_DEL_DEVICE)
 299                sysfs_remove_group(&pdev->dev.kobj, &lpss_attr_group);
 300
 301        return ret;
 302}
 303
 304static struct notifier_block acpi_lpss_nb = {
 305        .notifier_call = acpi_lpss_platform_notify,
 306};
 307
 308static struct acpi_scan_handler lpss_handler = {
 309        .ids = acpi_lpss_device_ids,
 310        .attach = acpi_lpss_create_device,
 311};
 312
 313void __init acpi_lpss_init(void)
 314{
 315        if (!lpt_clk_init()) {
 316                bus_register_notifier(&platform_bus_type, &acpi_lpss_nb);
 317                acpi_scan_add_handler(&lpss_handler);
 318        }
 319}
 320
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