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");