linux/drivers/acpi/acpi_amba.c
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   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
  22static 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
  36static 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
  48static 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                                dev->res.name = dev_name(&dev->dev);
  80                                address_found = true;
  81                        }
  82                        break;
  83                case IORESOURCE_IRQ:
  84                        if (irq_no < AMBA_NR_IRQS)
  85                                dev->irq[irq_no++] = rentry->res->start;
  86                        break;
  87                default:
  88                        dev_warn(&adev->dev, "Invalid resource\n");
  89                        break;
  90                }
  91        }
  92
  93        acpi_dev_free_resource_list(&resource_list);
  94
  95        /*
  96         * If the ACPI node has a parent and that parent has a physical device
  97         * attached to it, that physical device should be the parent of
  98         * the amba device we are about to create.
  99         */
 100        if (adev->parent)
 101                dev->dev.parent = acpi_get_first_physical_node(adev->parent);
 102
 103        ACPI_COMPANION_SET(&dev->dev, adev);
 104
 105        ret = amba_device_add(dev, &iomem_resource);
 106        if (ret) {
 107                dev_err(&adev->dev, "%s(): amba_device_add() failed (%d)\n",
 108                       __func__, ret);
 109                goto err_free;
 110        }
 111
 112        return 1;
 113
 114err_free:
 115        amba_device_put(dev);
 116        return ret;
 117}
 118
 119static struct acpi_scan_handler amba_handler = {
 120        .ids = amba_id_list,
 121        .attach = amba_handler_attach,
 122};
 123
 124void __init acpi_amba_init(void)
 125{
 126        amba_register_dummy_clk();
 127        acpi_scan_add_handler(&amba_handler);
 128}
 129