1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * WMI embedded Binary MOF driver 4 * 5 * Copyright (c) 2015 Andrew Lutomirski 6 * Copyright (C) 2017 VMware, Inc. All Rights Reserved. 7 */ 8 9 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 10 11 #include <linux/acpi.h> 12 #include <linux/device.h> 13 #include <linux/fs.h> 14 #include <linux/kernel.h> 15 #include <linux/module.h> 16 #include <linux/string.h> 17 #include <linux/sysfs.h> 18 #include <linux/types.h> 19 #include <linux/wmi.h> 20 21 #define WMI_BMOF_GUID "05901221-D566-11D1-B2F0-00A0C9062910" 22 23 struct bmof_priv { 24 union acpi_object *bmofdata; 25 struct bin_attribute bmof_bin_attr; 26 }; 27 28 static ssize_t 29 read_bmof(struct file *filp, struct kobject *kobj, 30 struct bin_attribute *attr, 31 char *buf, loff_t off, size_t count) 32 { 33 struct bmof_priv *priv = 34 container_of(attr, struct bmof_priv, bmof_bin_attr); 35 36 if (off < 0) 37 return -EINVAL; 38 39 if (off >= priv->bmofdata->buffer.length) 40 return 0; 41 42 if (count > priv->bmofdata->buffer.length - off) 43 count = priv->bmofdata->buffer.length - off; 44 45 memcpy(buf, priv->bmofdata->buffer.pointer + off, count); 46 return count; 47 } 48 49 static int wmi_bmof_probe(struct wmi_device *wdev, const void *context) 50 { 51 struct bmof_priv *priv; 52 int ret; 53 54 priv = devm_kzalloc(&wdev->dev, sizeof(struct bmof_priv), GFP_KERNEL); 55 if (!priv) 56 return -ENOMEM; 57 58 dev_set_drvdata(&wdev->dev, priv); 59 60 priv->bmofdata = wmidev_block_query(wdev, 0); 61 if (!priv->bmofdata) { 62 dev_err(&wdev->dev, "failed to read Binary MOF\n"); 63 return -EIO; 64 } 65 66 if (priv->bmofdata->type != ACPI_TYPE_BUFFER) { 67 dev_err(&wdev->dev, "Binary MOF is not a buffer\n"); 68 ret = -EIO; 69 goto err_free; 70 } 71 72 sysfs_bin_attr_init(&priv->bmof_bin_attr); 73 priv->bmof_bin_attr.attr.name = "bmof"; 74 priv->bmof_bin_attr.attr.mode = 0400; 75 priv->bmof_bin_attr.read = read_bmof; 76 priv->bmof_bin_attr.size = priv->bmofdata->buffer.length; 77 78 ret = sysfs_create_bin_file(&wdev->dev.kobj, &priv->bmof_bin_attr); 79 if (ret) 80 goto err_free; 81 82 return 0; 83 84 err_free: 85 kfree(priv->bmofdata); 86 return ret; 87 } 88 89 static int wmi_bmof_remove(struct wmi_device *wdev) 90 { 91 struct bmof_priv *priv = dev_get_drvdata(&wdev->dev); 92 93 sysfs_remove_bin_file(&wdev->dev.kobj, &priv->bmof_bin_attr); 94 kfree(priv->bmofdata); 95 return 0; 96 } 97 98 static const struct wmi_device_id wmi_bmof_id_table[] = { 99 { .guid_string = WMI_BMOF_GUID }, 100 { }, 101 }; 102 103 static struct wmi_driver wmi_bmof_driver = { 104 .driver = { 105 .name = "wmi-bmof", 106 }, 107 .probe = wmi_bmof_probe, 108 .remove = wmi_bmof_remove, 109 .id_table = wmi_bmof_id_table, 110 }; 111 112 module_wmi_driver(wmi_bmof_driver); 113 114 MODULE_DEVICE_TABLE(wmi, wmi_bmof_id_table); 115 MODULE_AUTHOR("Andrew Lutomirski <luto@kernel.org>"); 116 MODULE_DESCRIPTION("WMI embedded Binary MOF driver"); 117 MODULE_LICENSE("GPL"); 118