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(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, "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(&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(&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_DESCRIPTION("ACPI PCI Hot Plug Extension for Ampere Altra"); 128 MODULE_LICENSE("GPL"); 129