drivers/acpi/acpi_amba.c

   1
   2 /*
   3  * ACPI support for platform bus type.
   4  *
   5  * Copyright (C) 2015, Linaro Ltd
   6  * Author: Graeme Gregory <graeme.gregory@linaro.org>
   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/amba/bus.h>
  15 #include <linux/clkdev.h>
  16 #include <linux/clk-provider.h>
  17 #include <linux/device.h>
  18 #include <linux/err.h>
  19 #include <linux/ioport.h>
  20 #include <linux/kernel.h>
  21 #include <linux/module.h>
  22
  23 #include "internal.h"
  24
  25 static const struct acpi_device_id amba_id_list[] = {
  26         {"ARMH0061", 0}, /* PL061 GPIO Device */
  27         {"", 0},
  28 };
  29
  30 static void amba_register_dummy_clk(void)
  31 {
  32         static struct clk *amba_dummy_clk;
  33
  34         /* If clock already registered */
  35         if (amba_dummy_clk)
  36                 return;
  37
  38         amba_dummy_clk = clk_register_fixed_rate(NULL, "apb_pclk", NULL, 0, 0);
  39         clk_register_clkdev(amba_dummy_clk, "apb_pclk", NULL);
  40 }
  41
  42 static int amba_handler_attach(struct acpi_device *adev,
  43                                 const struct acpi_device_id *id)
  44 {
  45         struct amba_device *dev;
  46         struct resource_entry *rentry;
  47         struct list_head resource_list;
  48         bool address_found = false;
  49         int irq_no = 0;
  50         int ret;
  51
  52         /* If the ACPI node already has a physical device attached, skip it. */
  53         if (adev->physical_node_count)
  54                 return 0;
  55
  56         dev = amba_device_alloc(dev_name(&adev->dev), 0, 0);
  57         if (!dev) {
  58                 dev_err(&adev->dev, "%s(): amba_device_alloc() failed\n",
  59                         __func__);
  60                 return -ENOMEM;
  61         }
  62
  63         INIT_LIST_HEAD(&resource_list);
  64         ret = acpi_dev_get_resources(adev, &resource_list, NULL, NULL);
  65         if (ret < 0)
  66                 goto err_free;
  67
  68         list_for_each_entry(rentry, &resource_list, node) {
  69                 switch (resource_type(rentry->res)) {
  70                 case IORESOURCE_MEM:
  71                         if (!address_found) {
  72                                 dev->res = *rentry->res;
  73                                 address_found = true;
  74                         }
  75                         break;
  76                 case IORESOURCE_IRQ:
  77                         if (irq_no < AMBA_NR_IRQS)
  78                                 dev->irq[irq_no++] = rentry->res->start;
  79                         break;
  80                 default:
  81                         dev_warn(&adev->dev, "Invalid resource\n");
  82                         break;
  83                 }
  84         }
  85
  86         acpi_dev_free_resource_list(&resource_list);
  87
  88         /*
  89          * If the ACPI node has a parent and that parent has a physical device
  90          * attached to it, that physical device should be the parent of
  91          * the amba device we are about to create.
  92          */
  93         if (adev->parent)
  94                 dev->dev.parent = acpi_get_first_physical_node(adev->parent);
  95
  96         ACPI_COMPANION_SET(&dev->dev, adev);
  97
  98         ret = amba_device_add(dev, &iomem_resource);
  99         if (ret) {
 100                 dev_err(&adev->dev, "%s(): amba_device_add() failed (%d)\n",
 101                        __func__, ret);
 102                 goto err_free;
 103         }
 104
 105         return 1;
 106
 107 err_free:
 108         amba_device_put(dev);
 109         return ret;
 110 }
 111
 112 static struct acpi_scan_handler amba_handler = {
 113         .ids = amba_id_list,
 114         .attach = amba_handler_attach,
 115 };
 116
 117 void __init acpi_amba_init(void)
 118 {
 119         amba_register_dummy_clk();
 120         acpi_scan_add_handler(&amba_handler);
 121 }