// SPDX-License-Identifier: GPL-2.0-only /* * WMI methods for use with dell-smbios * * Copyright (c) 2017 Dell Inc. */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include <linux/dmi.h> #include <linux/list.h> #include <linux/module.h> #include <linux/mutex.h> #include <linux/uaccess.h> #include <linux/wmi.h> #include "dell-smbios.h" #include "dell-wmi-descriptor.h" static DEFINE_MUTEX(call_mutex); static DEFINE_MUTEX(list_mutex); static int wmi_supported; struct misc_bios_flags_structure { struct dmi_header header; u16 flags0; } __packed; #define FLAG_HAS_ACPI_WMI 0x02 #define DELL_WMI_SMBIOS_GUID "A80593CE-A997-11DA-B012-B622A1EF5492" struct wmi_smbios_priv { struct dell_wmi_smbios_buffer *buf; struct list_head list; struct wmi_device *wdev; struct device *child; u32 req_buf_size; }; static LIST_HEAD(wmi_list); static inline struct wmi_smbios_priv *get_first_smbios_priv(void) { return list_first_entry_or_null(&wmi_list, struct wmi_smbios_priv, list); } static int run_smbios_call(struct wmi_device *wdev) { struct acpi_buffer output = {ACPI_ALLOCATE_BUFFER, NULL}; struct wmi_smbios_priv *priv; struct acpi_buffer input; union acpi_object *obj; acpi_status status; priv = dev_get_drvdata(&wdev->dev); input.length = priv->req_buf_size - sizeof(u64); input.pointer = &priv->buf->std; dev_dbg(&wdev->dev, "evaluating: %u/%u [%x,%x,%x,%x]\n", priv->buf->std.cmd_class, priv->buf->std.cmd_select, priv->buf->std.input[0], priv->buf->std.input[1], priv->buf->std.input[2], priv->buf->std.input[3]); status = wmidev_evaluate_method(wdev, 0, 1, &input, &output); if (ACPI_FAILURE(status)) return -EIO; obj = (union acpi_object *)output.pointer; if (obj->type != ACPI_TYPE_BUFFER) { dev_dbg(&wdev->dev, "received type: %d\n", obj->type); if (obj->type == ACPI_TYPE_INTEGER) dev_dbg(&wdev->dev, "SMBIOS call failed: %llu\n", obj->integer.value); kfree(output.pointer); return -EIO; } memcpy(input.pointer, obj->buffer.pointer, obj->buffer.length); dev_dbg(&wdev->dev, "result: [%08x,%08x,%08x,%08x]\n", priv->buf->std.output[0], priv->buf->std.output[1], priv->buf->std.output[2], priv->buf->std.output[3]); kfree(output.pointer); return 0; } static int dell_smbios_wmi_call(struct calling_interface_buffer *buffer) { struct wmi_smbios_priv *priv; size_t difference; size_t size; int ret; mutex_lock(&call_mutex); priv = get_first_smbios_priv(); if (!priv) { ret = -ENODEV; goto out_wmi_call; } size = sizeof(struct calling_interface_buffer); difference = priv->req_buf_size - sizeof(u64) - size; memset(&priv->buf->ext, 0, difference); memcpy(&priv->buf->std, buffer, size); ret = run_smbios_call(priv->wdev); memcpy(buffer, &priv->buf->std, size); out_wmi_call: mutex_unlock(&call_mutex); return ret; } static long dell_smbios_wmi_filter(struct wmi_device *wdev, unsigned int cmd, struct wmi_ioctl_buffer *arg) { struct wmi_smbios_priv *priv; int ret = 0; switch (cmd) { case DELL_WMI_SMBIOS_CMD: mutex_lock(&call_mutex); priv = dev_get_drvdata(&wdev->dev); if (!priv) { ret = -ENODEV; goto fail_smbios_cmd; } memcpy(priv->buf, arg, priv->req_buf_size); if (dell_smbios_call_filter(&wdev->dev, &priv->buf->std)) { dev_err(&wdev->dev, "Invalid call %d/%d:%8x\n", priv->buf->std.cmd_class, priv->buf->std.cmd_select, priv->buf->std.input[0]); ret = -EFAULT; goto fail_smbios_cmd; } ret = run_smbios_call(priv->wdev); if (ret) goto fail_smbios_cmd; memcpy(arg, priv->buf, priv->req_buf_size); fail_smbios_cmd: mutex_unlock(&call_mutex); break; default: ret = -ENOIOCTLCMD; } return ret; } static int dell_smbios_wmi_probe(struct wmi_device *wdev, const void *context) { struct wmi_driver *wdriver = container_of(wdev->dev.driver, struct wmi_driver, driver); struct wmi_smbios_priv *priv; u32 hotfix; int count; int ret; ret = dell_wmi_get_descriptor_valid(); if (ret) return ret; priv = devm_kzalloc(&wdev->dev, sizeof(struct wmi_smbios_priv), GFP_KERNEL); if (!priv) return -ENOMEM; /* WMI buffer size will be either 4k or 32k depending on machine */ if (!dell_wmi_get_size(&priv->req_buf_size)) return -EPROBE_DEFER; /* some SMBIOS calls fail unless BIOS contains hotfix */ if (!dell_wmi_get_hotfix(&hotfix)) return -EPROBE_DEFER; if (!hotfix) { dev_warn(&wdev->dev, "WMI SMBIOS userspace interface not supported(%u), try upgrading to a newer BIOS\n", hotfix); wdriver->filter_callback = NULL; } /* add in the length object we will use internally with ioctl */ priv->req_buf_size += sizeof(u64); ret = set_required_buffer_size(wdev, priv->req_buf_size); if (ret) return ret; count = get_order(priv->req_buf_size); priv->buf = (void *)__get_free_pages(GFP_KERNEL, count); if (!priv->buf) return -ENOMEM; /* ID is used by dell-smbios to set priority of drivers */ wdev->dev.id = 1; ret = dell_smbios_register_device(&wdev->dev, &dell_smbios_wmi_call); if (ret) goto fail_register; priv->wdev = wdev; dev_set_drvdata(&wdev->dev, priv); mutex_lock(&list_mutex); list_add_tail(&priv->list, &wmi_list); mutex_unlock(&list_mutex); return 0; fail_register: free_pages((unsigned long)priv->buf, count); return ret; } static void dell_smbios_wmi_remove(struct wmi_device *wdev) { struct wmi_smbios_priv *priv = dev_get_drvdata(&wdev->dev); int count; mutex_lock(&call_mutex); mutex_lock(&list_mutex); list_del(&priv->list); mutex_unlock(&list_mutex); dell_smbios_unregister_device(&wdev->dev); count = get_order(priv->req_buf_size); free_pages((unsigned long)priv->buf, count); mutex_unlock(&call_mutex); } static const struct wmi_device_id dell_smbios_wmi_id_table[] = { { .guid_string = DELL_WMI_SMBIOS_GUID }, { }, }; static void parse_b1_table(const struct dmi_header *dm) { struct misc_bios_flags_structure *flags = container_of(dm, struct misc_bios_flags_structure, header); /* 4 bytes header, 8 bytes flags */ if (dm->length < 12) return; if (dm->handle != 0xb100) return; if ((flags->flags0 & FLAG_HAS_ACPI_WMI)) wmi_supported = 1; } static void find_b1(const struct dmi_header *dm, void *dummy) { switch (dm->type) { case 0xb1: /* misc bios flags */ parse_b1_table(dm); break; } } static struct wmi_driver dell_smbios_wmi_driver = { .driver = { .name = "dell-smbios", }, .probe = dell_smbios_wmi_probe, .remove = dell_smbios_wmi_remove, .id_table = dell_smbios_wmi_id_table, .filter_callback = dell_smbios_wmi_filter, }; int init_dell_smbios_wmi(void) { dmi_walk(find_b1, NULL); if (!wmi_supported) return -ENODEV; return wmi_driver_register(&dell_smbios_wmi_driver); } void exit_dell_smbios_wmi(void) { if (wmi_supported) wmi_driver_unregister(&dell_smbios_wmi_driver); } MODULE_DEVICE_TABLE(wmi, dell_smbios_wmi_id_table);