root/drivers/acpi/acpi_amba.c

DEFINITIONS

1. amba_register_dummy_clk
2. amba_handler_attach
3. acpi_amba_init

   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 <graeme.gregory@linaro.org>
   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         {"ARMHC500", 0}, /* ARM CoreSight ETM4x */
  25         {"ARMHC501", 0}, /* ARM CoreSight ETR */
  26         {"ARMHC502", 0}, /* ARM CoreSight STM */
  27         {"ARMHC503", 0}, /* ARM CoreSight Debug */
  28         {"ARMHC979", 0}, /* ARM CoreSight TPIU */
  29         {"ARMHC97C", 0}, /* ARM CoreSight SoC-400 TMC, SoC-600 ETF/ETB */
  30         {"ARMHC98D", 0}, /* ARM CoreSight Dynamic Replicator */
  31         {"ARMHC9CA", 0}, /* ARM CoreSight CATU */
  32         {"ARMHC9FF", 0}, /* ARM CoreSight Dynamic Funnel */
  33         {"", 0},
  34 };
  35 
  36 static void amba_register_dummy_clk(void)
  37 {
  38         static struct clk *amba_dummy_clk;
  39 
  40         /* If clock already registered */
  41         if (amba_dummy_clk)
  42                 return;
  43 
  44         amba_dummy_clk = clk_register_fixed_rate(NULL, "apb_pclk", NULL, 0, 0);
  45         clk_register_clkdev(amba_dummy_clk, "apb_pclk", NULL);
  46 }
  47 
  48 static int amba_handler_attach(struct acpi_device *adev,
  49                                 const struct acpi_device_id *id)
  50 {
  51         struct amba_device *dev;
  52         struct resource_entry *rentry;
  53         struct list_head resource_list;
  54         bool address_found = false;
  55         int irq_no = 0;
  56         int ret;
  57 
  58         /* If the ACPI node already has a physical device attached, skip it. */
  59         if (adev->physical_node_count)
  60                 return 0;
  61 
  62         dev = amba_device_alloc(dev_name(&adev->dev), 0, 0);
  63         if (!dev) {
  64                 dev_err(&adev->dev, "%s(): amba_device_alloc() failed\n",
  65                         __func__);
  66                 return -ENOMEM;
  67         }
  68 
  69         INIT_LIST_HEAD(&resource_list);
  70         ret = acpi_dev_get_resources(adev, &resource_list, NULL, NULL);
  71         if (ret < 0)
  72                 goto err_free;
  73 
  74         list_for_each_entry(rentry, &resource_list, node) {
  75                 switch (resource_type(rentry->res)) {
  76                 case IORESOURCE_MEM:
  77                         if (!address_found) {
  78                                 dev->res = *rentry->res;
  79                                 address_found = true;
  80                         }
  81                         break;
  82                 case IORESOURCE_IRQ:
  83                         if (irq_no < AMBA_NR_IRQS)
  84                                 dev->irq[irq_no++] = rentry->res->start;
  85                         break;
  86                 default:
  87                         dev_warn(&adev->dev, "Invalid resource\n");
  88                         break;
  89                 }
  90         }
  91 
  92         acpi_dev_free_resource_list(&resource_list);
  93 
  94         /*
  95          * If the ACPI node has a parent and that parent has a physical device
  96          * attached to it, that physical device should be the parent of
  97          * the amba device we are about to create.
  98          */
  99         if (adev->parent)
 100                 dev->dev.parent = acpi_get_first_physical_node(adev->parent);
 101 
 102         ACPI_COMPANION_SET(&dev->dev, adev);
 103 
 104         ret = amba_device_add(dev, &iomem_resource);
 105         if (ret) {
 106                 dev_err(&adev->dev, "%s(): amba_device_add() failed (%d)\n",
 107                        __func__, ret);
 108                 goto err_free;
 109         }
 110 
 111         return 1;
 112 
 113 err_free:
 114         amba_device_put(dev);
 115         return ret;
 116 }
 117 
 118 static struct acpi_scan_handler amba_handler = {
 119         .ids = amba_id_list,
 120         .attach = amba_handler_attach,
 121 };
 122 
 123 void __init acpi_amba_init(void)
 124 {
 125         amba_register_dummy_clk();
 126         acpi_scan_add_handler(&amba_handler);
 127 }