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 | |
28 | static u32 led_service_id[4]; |
29 | |
30 | static 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 | |
39 | static 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 | |
75 | static int get_attention_status(struct hotplug_slot *slot, u8 *status) |
76 | { |
77 | return -EINVAL; |
78 | } |
79 | |
80 | static 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 | |
86 | static 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: &ere_altra_attn); |
98 | if (ret) { |
99 | dev_err(&pdev->dev, "can't register driver\n" ); |
100 | return ret; |
101 | } |
102 | return 0; |
103 | } |
104 | |
105 | static void altra_led_remove(struct platform_device *pdev) |
106 | { |
107 | acpiphp_unregister_attention(info: &ere_altra_attn); |
108 | } |
109 | |
110 | static const struct acpi_device_id altra_led_ids[] = { |
111 | { "AMPC0008" , 0 }, |
112 | { } |
113 | }; |
114 | MODULE_DEVICE_TABLE(acpi, altra_led_ids); |
115 | |
116 | static 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 | }; |
124 | module_platform_driver(altra_led_driver); |
125 | |
126 | MODULE_AUTHOR("D Scott Phillips <scott@os.amperecomputing.com>" ); |
127 | MODULE_LICENSE("GPL" ); |
128 | |