1// SPDX-License-Identifier: GPL-2.0
2/*
3 * ACPI PCI Hot Plug Extension for Ampere Altra. Allows control of
4 * attention LEDs via requests to system firmware.
5 *
6 * Copyright (C) 2023 Ampere Computing LLC
7 */
8
9#define pr_fmt(fmt) "acpiphp_ampere_altra: " fmt
10
11#include <linux/init.h>
12#include <linux/module.h>
13#include <linux/pci.h>
14#include <linux/pci_hotplug.h>
15#include <linux/platform_device.h>
16
17#include "acpiphp.h"
18
19#define HANDLE_OPEN	0xb0200000
20#define HANDLE_CLOSE	0xb0300000
21#define REQUEST		0xf0700000
22#define LED_CMD		0x00000004
23#define LED_ATTENTION	0x00000002
24#define LED_SET_ON	0x00000001
25#define LED_SET_OFF	0x00000002
26#define LED_SET_BLINK	0x00000003
27
28static u32 led_service_id[4];
29
30static int led_status(u8 status)
31{
32	switch (status) {
33	case 1: return LED_SET_ON;
34	case 2: return LED_SET_BLINK;
35	default: return LED_SET_OFF;
36	}
37}
38
39static int set_attention_status(struct hotplug_slot *slot, u8 status)
40{
41	struct arm_smccc_res res;
42	struct pci_bus *bus;
43	struct pci_dev *root_port;
44	unsigned long flags;
45	u32 handle;
46	int ret = 0;
47
48	bus = slot->pci_slot->bus;
49	root_port = pcie_find_root_port(bus->self);
50	if (!root_port)
51		return -ENODEV;
52
53	local_irq_save(flags);
54	arm_smccc_smc(HANDLE_OPEN, led_service_id[0], led_service_id[1],
55		      led_service_id[2], led_service_id[3], 0, 0, 0, &res);
56	if (res.a0) {
57		ret = -ENODEV;
58		goto out;
59	}
60	handle = res.a1 & 0xffff0000;
61
62	arm_smccc_smc(REQUEST, LED_CMD, led_status(status), LED_ATTENTION,
63		 (PCI_SLOT(root_port->devfn) << 4) | (pci_domain_nr(bus) & 0xf),
64		 0, 0, handle, &res);
65	if (res.a0)
66		ret = -ENODEV;
67
68	arm_smccc_smc(HANDLE_CLOSE, handle, 0, 0, 0, 0, 0, 0, &res);
69
70 out:
71	local_irq_restore(flags);
72	return ret;
73}
74
75static int get_attention_status(struct hotplug_slot *slot, u8 *status)
76{
77	return -EINVAL;
78}
79
80static struct acpiphp_attention_info ampere_altra_attn = {
81	.set_attn = set_attention_status,
82	.get_attn = get_attention_status,
83	.owner = THIS_MODULE,
84};
85
86static int altra_led_probe(struct platform_device *pdev)
87{
88	struct fwnode_handle *fwnode = dev_fwnode(&pdev->dev);
89	int ret;
90
91	ret = fwnode_property_read_u32_array(fwnode, "uuid", led_service_id, 4);
92	if (ret) {
93		dev_err(&pdev->dev, "can't find uuid\n");
94		return ret;
95	}
96
97	ret = acpiphp_register_attention(&ampere_altra_attn);
98	if (ret) {
99		dev_err(&pdev->dev, "can't register driver\n");
100		return ret;
101	}
102	return 0;
103}
104
105static void altra_led_remove(struct platform_device *pdev)
106{
107	acpiphp_unregister_attention(&ampere_altra_attn);
108}
109
110static const struct acpi_device_id altra_led_ids[] = {
111	{ "AMPC0008", 0 },
112	{ }
113};
114MODULE_DEVICE_TABLE(acpi, altra_led_ids);
115
116static struct platform_driver altra_led_driver = {
117	.driver = {
118		.name = "ampere-altra-leds",
119		.acpi_match_table = altra_led_ids,
120	},
121	.probe = altra_led_probe,
122	.remove_new = altra_led_remove,
123};
124module_platform_driver(altra_led_driver);
125
126MODULE_AUTHOR("D Scott Phillips <scott@os.amperecomputing.com>");
127MODULE_LICENSE("GPL");
128