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(dev: 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, propname: "uuid", val: led_service_id, nval: 4);
92 if (ret) {
93 dev_err(&pdev->dev, "can't find uuid\n");
94 return ret;
95 }
96
97 ret = acpiphp_register_attention(info: &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(info: &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

source code of linux/drivers/pci/hotplug/acpiphp_ampere_altra.c