drivers/acpi/acpi_amba.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2
   3 /*
   4  * ACPI support for platform bus type.
   5  *
   6  * Copyright (C) 2015, Linaro Ltd
   7  * Author: Graeme Gregory <[email protected]>
   8  */
   9
  10 #include <linux/acpi.h>
  11 #include <linux/amba/bus.h>
  12 #include <linux/clkdev.h>
  13 #include <linux/clk-provider.h>
  14 #include <linux/device.h>
  15 #include <linux/err.h>
  16 #include <linux/ioport.h>
  17 #include <linux/kernel.h>
  18 #include <linux/module.h>
  19
  20 #include "internal.h"
  21
  22 static const struct acpi_device_id amba_id_list[] = {
  23         {"ARMH0061", 0}, /* PL061 GPIO Device */
  24         {"", 0},
  25 };
  26
  27 static void amba_register_dummy_clk(void)
  28 {
  29         static struct clk *amba_dummy_clk;
  30
  31         /* If clock already registered */
  32         if (amba_dummy_clk)
  33                 return;
  34
  35         amba_dummy_clk = clk_register_fixed_rate(NULL, "apb_pclk", NULL, 0, 0);
  36         clk_register_clkdev(amba_dummy_clk, "apb_pclk", NULL);
  37 }
  38
  39 static int amba_handler_attach(struct acpi_device *adev,
  40                                 const struct acpi_device_id *id)
  41 {
  42         struct amba_device *dev;
  43         struct resource_entry *rentry;
  44         struct list_head resource_list;
  45         bool address_found = false;
  46         int irq_no = 0;
  47         int ret;
  48
  49         /* If the ACPI node already has a physical device attached, skip it. */
  50         if (adev->physical_node_count)
  51                 return 0;
  52
  53         dev = amba_device_alloc(dev_name(&adev->dev), 0, 0);
  54         if (!dev) {
  55                 dev_err(&adev->dev, "%s(): amba_device_alloc() failed\n",
  56                         __func__);
  57                 return -ENOMEM;
  58         }
  59
  60         INIT_LIST_HEAD(&resource_list);
  61         ret = acpi_dev_get_resources(adev, &resource_list, NULL, NULL);
  62         if (ret < 0)
  63                 goto err_free;
  64
  65         list_for_each_entry(rentry, &resource_list, node) {
  66                 switch (resource_type(rentry->res)) {
  67                 case IORESOURCE_MEM:
  68                         if (!address_found) {
  69                                 dev->res = *rentry->res;
  70                                 address_found = true;
  71                         }
  72                         break;
  73                 case IORESOURCE_IRQ:
  74                         if (irq_no < AMBA_NR_IRQS)
  75                                 dev->irq[irq_no++] = rentry->res->start;
  76                         break;
  77                 default:
  78                         dev_warn(&adev->dev, "Invalid resource\n");
  79                         break;
  80                 }
  81         }
  82
  83         acpi_dev_free_resource_list(&resource_list);
  84
  85         /*
  86          * If the ACPI node has a parent and that parent has a physical device
  87          * attached to it, that physical device should be the parent of
  88          * the amba device we are about to create.
  89          */
  90         if (adev->parent)
  91                 dev->dev.parent = acpi_get_first_physical_node(adev->parent);
  92
  93         ACPI_COMPANION_SET(&dev->dev, adev);
  94
  95         ret = amba_device_add(dev, &iomem_resource);
  96         if (ret) {
  97                 dev_err(&adev->dev, "%s(): amba_device_add() failed (%d)\n",
  98                        __func__, ret);
  99                 goto err_free;
 100         }
 101
 102         return 1;
 103
 104 err_free:
 105         amba_device_put(dev);
 106         return ret;
 107 }
 108
 109 static struct acpi_scan_handler amba_handler = {
 110         .ids = amba_id_list,
 111         .attach = amba_handler_attach,
 112 };
 113
 114 void __init acpi_amba_init(void)
 115 {
 116         amba_register_dummy_clk();
 117         acpi_scan_add_handler(&amba_handler);
 118 }