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,
 39						CLK_IS_ROOT, 0);
 40	clk_register_clkdev(amba_dummy_clk, "apb_pclk", NULL);
 41}
 42
 43static int amba_handler_attach(struct acpi_device *adev,
 44				const struct acpi_device_id *id)
 45{
 46	struct amba_device *dev;
 47	struct resource_entry *rentry;
 48	struct list_head resource_list;
 49	bool address_found = false;
 50	int irq_no = 0;
 51	int ret;
 52
 53	/* If the ACPI node already has a physical device attached, skip it. */
 54	if (adev->physical_node_count)
 55		return 0;
 56
 57	dev = amba_device_alloc(dev_name(&adev->dev), 0, 0);
 58	if (!dev) {
 59		dev_err(&adev->dev, "%s(): amba_device_alloc() failed\n",
 60			__func__);
 61		return -ENOMEM;
 62	}
 63
 64	INIT_LIST_HEAD(&resource_list);
 65	ret = acpi_dev_get_resources(adev, &resource_list, NULL, NULL);
 66	if (ret < 0)
 67		goto err_free;
 68
 69	list_for_each_entry(rentry, &resource_list, node) {
 70		switch (resource_type(rentry->res)) {
 71		case IORESOURCE_MEM:
 72			if (!address_found) {
 73				dev->res = *rentry->res;
 74				address_found = true;
 75			}
 76			break;
 77		case IORESOURCE_IRQ:
 78			if (irq_no < AMBA_NR_IRQS)
 79				dev->irq[irq_no++] = rentry->res->start;
 80			break;
 81		default:
 82			dev_warn(&adev->dev, "Invalid resource\n");
 83			break;
 84		}
 85	}
 86
 87	acpi_dev_free_resource_list(&resource_list);
 88
 89	/*
 90	 * If the ACPI node has a parent and that parent has a physical device
 91	 * attached to it, that physical device should be the parent of
 92	 * the amba device we are about to create.
 93	 */
 94	if (adev->parent)
 95		dev->dev.parent = acpi_get_first_physical_node(adev->parent);
 96
 97	ACPI_COMPANION_SET(&dev->dev, adev);
 98
 99	ret = amba_device_add(dev, &iomem_resource);
100	if (ret) {
101		dev_err(&adev->dev, "%s(): amba_device_add() failed (%d)\n",
102		       __func__, ret);
103		goto err_free;
104	}
105
106	return 1;
107
108err_free:
109	amba_device_put(dev);
110	return ret;
111}
112
113static struct acpi_scan_handler amba_handler = {
114	.ids = amba_id_list,
115	.attach = amba_handler_attach,
116};
117
118void __init acpi_amba_init(void)
119{
120	amba_register_dummy_clk();
121	acpi_scan_add_handler(&amba_handler);
122}