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
  36 struct lpss_device_desc {
  37         bool clk_required;
  38         const char *clkdev_name;
  39         bool ltr_required;
  40         unsigned int prv_offset;
  41 };
  42
  43 static struct lpss_device_desc lpss_dma_desc = {
  44         .clk_required = true,
  45         .clkdev_name = "hclk",
  46 };
  47
  48 struct 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
  55 static struct lpss_device_desc lpt_dev_desc = {
  56         .clk_required = true,
  57         .prv_offset = 0x800,
  58         .ltr_required = true,
  59 };
  60
  61 static struct lpss_device_desc lpt_sdio_dev_desc = {
  62         .prv_offset = 0x1000,
  63         .ltr_required = true,
  64 };
  65
  66 static 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
  83 static 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. */
  90 static struct platform_device *lpss_clk_dev;
  91
  92 static inline void lpt_register_clock_device(void)
  93 {
  94         lpss_clk_dev = platform_device_register_simple("clk-lpt", -1, NULL, 0);
  95 }
  96
  97 static 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
 131 static 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                         break;
 159                 }
 160
 161         acpi_dev_free_resource_list(&resource_list);
 162
 163         pdata->dev_desc = dev_desc;
 164
 165         if (dev_desc->clk_required) {
 166                 ret = register_device_clock(adev, pdata);
 167                 if (ret) {
 168                         /* Skip the device, but continue the namespace scan. */
 169                         ret = 0;
 170                         goto err_out;
 171                 }
 172         }
 173
 174         /*
 175          * This works around a known issue in ACPI tables where LPSS devices
 176          * have _PS0 and _PS3 without _PSC (and no power resources), so
 177          * acpi_bus_init_power() will assume that the BIOS has put them into D0.
 178          */
 179         ret = acpi_device_fix_up_power(adev);
 180         if (ret) {
 181                 /* Skip the device, but continue the namespace scan. */
 182                 ret = 0;
 183                 goto err_out;
 184         }
 185
 186         adev->driver_data = pdata;
 187         ret = acpi_create_platform_device(adev, id);
 188         if (ret > 0)
 189                 return ret;
 190
 191         adev->driver_data = NULL;
 192
 193  err_out:
 194         kfree(pdata);
 195         return ret;
 196 }
 197
 198 static int lpss_reg_read(struct device *dev, unsigned int reg, u32 *val)
 199 {
 200         struct acpi_device *adev;
 201         struct lpss_private_data *pdata;
 202         unsigned long flags;
 203         int ret;
 204
 205         ret = acpi_bus_get_device(ACPI_HANDLE(dev), &adev);
 206         if (WARN_ON(ret))
 207                 return ret;
 208
 209         spin_lock_irqsave(&dev->power.lock, flags);
 210         if (pm_runtime_suspended(dev)) {
 211                 ret = -EAGAIN;
 212                 goto out;
 213         }
 214         pdata = acpi_driver_data(adev);
 215         if (WARN_ON(!pdata || !pdata->mmio_base)) {
 216                 ret = -ENODEV;
 217                 goto out;
 218         }
 219         *val = readl(pdata->mmio_base + pdata->dev_desc->prv_offset + reg);
 220
 221  out:
 222         spin_unlock_irqrestore(&dev->power.lock, flags);
 223         return ret;
 224 }
 225
 226 static ssize_t lpss_ltr_show(struct device *dev, struct device_attribute *attr,
 227                              char *buf)
 228 {
 229         u32 ltr_value = 0;
 230         unsigned int reg;
 231         int ret;
 232
 233         reg = strcmp(attr->attr.name, "auto_ltr") ? LPSS_SW_LTR : LPSS_AUTO_LTR;
 234         ret = lpss_reg_read(dev, reg, &ltr_value);
 235         if (ret)
 236                 return ret;
 237
 238         return snprintf(buf, PAGE_SIZE, "%08x\n", ltr_value);
 239 }
 240
 241 static ssize_t lpss_ltr_mode_show(struct device *dev,
 242                                   struct device_attribute *attr, char *buf)
 243 {
 244         u32 ltr_mode = 0;
 245         char *outstr;
 246         int ret;
 247
 248         ret = lpss_reg_read(dev, LPSS_GENERAL, &ltr_mode);
 249         if (ret)
 250                 return ret;
 251
 252         outstr = (ltr_mode & LPSS_GENERAL_LTR_MODE_SW) ? "sw" : "auto";
 253         return sprintf(buf, "%s\n", outstr);
 254 }
 255
 256 static DEVICE_ATTR(auto_ltr, S_IRUSR, lpss_ltr_show, NULL);
 257 static DEVICE_ATTR(sw_ltr, S_IRUSR, lpss_ltr_show, NULL);
 258 static DEVICE_ATTR(ltr_mode, S_IRUSR, lpss_ltr_mode_show, NULL);
 259
 260 static struct attribute *lpss_attrs[] = {
 261         &dev_attr_auto_ltr.attr,
 262         &dev_attr_sw_ltr.attr,
 263         &dev_attr_ltr_mode.attr,
 264         NULL,
 265 };
 266
 267 static struct attribute_group lpss_attr_group = {
 268         .attrs = lpss_attrs,
 269         .name = "lpss_ltr",
 270 };
 271
 272 static int acpi_lpss_platform_notify(struct notifier_block *nb,
 273                                      unsigned long action, void *data)
 274 {
 275         struct platform_device *pdev = to_platform_device(data);
 276         struct lpss_private_data *pdata;
 277         struct acpi_device *adev;
 278         const struct acpi_device_id *id;
 279         int ret = 0;
 280
 281         id = acpi_match_device(acpi_lpss_device_ids, &pdev->dev);
 282         if (!id || !id->driver_data)
 283                 return 0;
 284
 285         if (acpi_bus_get_device(ACPI_HANDLE(&pdev->dev), &adev))
 286                 return 0;
 287
 288         pdata = acpi_driver_data(adev);
 289         if (!pdata || !pdata->mmio_base || !pdata->dev_desc->ltr_required)
 290                 return 0;
 291
 292         if (pdata->mmio_size < pdata->dev_desc->prv_offset + LPSS_LTR_SIZE) {
 293                 dev_err(&pdev->dev, "MMIO size insufficient to access LTR\n");
 294                 return 0;
 295         }
 296
 297         if (action == BUS_NOTIFY_ADD_DEVICE)
 298                 ret = sysfs_create_group(&pdev->dev.kobj, &lpss_attr_group);
 299         else if (action == BUS_NOTIFY_DEL_DEVICE)
 300                 sysfs_remove_group(&pdev->dev.kobj, &lpss_attr_group);
 301
 302         return ret;
 303 }
 304
 305 static struct notifier_block acpi_lpss_nb = {
 306         .notifier_call = acpi_lpss_platform_notify,
 307 };
 308
 309 static struct acpi_scan_handler lpss_handler = {
 310         .ids = acpi_lpss_device_ids,
 311         .attach = acpi_lpss_create_device,
 312 };
 313
 314 void __init acpi_lpss_init(void)
 315 {
 316         if (!lpt_clk_init()) {
 317                 bus_register_notifier(&platform_bus_type, &acpi_lpss_nb);
 318                 acpi_scan_add_handler(&lpss_handler);
 319         }
 320 }