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
 25static const struct acpi_device_id amba_id_list[] = {
 26	{"ARMH0061", 0}, /* PL061 GPIO Device */
 27	{"", 0},
 28};
 29
 30static 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
 42static 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
107err_free:
108	amba_device_put(dev);
109	return ret;
110}
111
112static struct acpi_scan_handler amba_handler = {
113	.ids = amba_id_list,
114	.attach = amba_handler_attach,
115};
116
117void __init acpi_amba_init(void)
118{
119	amba_register_dummy_clk();
120	acpi_scan_add_handler(&amba_handler);
121}