diff options
Diffstat (limited to 'drivers/misc/mei/mei_lb.c')
| -rw-r--r-- | drivers/misc/mei/mei_lb.c | 312 |
1 files changed, 312 insertions, 0 deletions
diff --git a/drivers/misc/mei/mei_lb.c b/drivers/misc/mei/mei_lb.c new file mode 100644 index 000000000000..77686b108d3c --- /dev/null +++ b/drivers/misc/mei/mei_lb.c @@ -0,0 +1,312 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2025 Intel Corporation + */ + +#include <linux/component.h> +#include <linux/mei_cl_bus.h> +#include <linux/module.h> +#include <linux/overflow.h> +#include <linux/pci.h> +#include <linux/slab.h> +#include <linux/uuid.h> + +#include <drm/intel/i915_component.h> +#include <drm/intel/intel_lb_mei_interface.h> + +#include "mkhi.h" + +/** + * DOC: Late Binding Firmware Update/Upload + * + * Late Binding is a firmware update/upload mechanism that allows configuration + * payloads to be securely delivered and applied at runtime, rather than + * being embedded in the system firmware image (e.g., IFWI or SPI flash). + * + * This mechanism is used to update device-level configuration such as: + * - Fan controller + * - Voltage regulator (VR) + * + * Key Characteristics: + * --------------------- + * - Runtime Delivery: + * Firmware blobs are loaded by the host driver (e.g., Xe KMD) + * after the GPU or SoC has booted. + * + * - Secure and Authenticated: + * All payloads are signed and verified by the authentication firmware. + * + * - No Firmware Flashing Required: + * Updates are applied in volatile memory and do not require SPI flash + * modification or system reboot. + * + * - Re-entrant: + * Multiple updates of the same or different types can be applied + * sequentially within a single boot session. + * + * - Version Controlled: + * Each payload includes version and security version number (SVN) + * metadata to support anti-rollback enforcement. + * + * Upload Flow: + * ------------ + * 1. Host driver (KMD or user-space tool) loads the late binding firmware. + * 2. Firmware is passed to the MEI interface and forwarded to + * authentication firmware. + * 3. Authentication firmware authenticates the payload and extracts + * command and data arrays. + * 4. Authentication firmware delivers the configuration to PUnit/PCODE. + * 5. Status is returned back to the host via MEI. + */ + +#define INTEL_LB_CMD 0x12 +#define INTEL_LB_RSP (INTEL_LB_CMD | 0x80) + +#define INTEL_LB_SEND_TIMEOUT_MSEC 3000 +#define INTEL_LB_RECV_TIMEOUT_MSEC 3000 + +/** + * struct mei_lb_req - Late Binding request structure + * @header: MKHI message header (see struct mkhi_msg_hdr) + * @type: Type of the Late Binding payload + * @flags: Flags to be passed to the authentication firmware (e.g. %INTEL_LB_FLAGS_IS_PERSISTENT) + * @reserved: Reserved for future use by authentication firmware, must be set to 0 + * @payload_size: Size of the payload data in bytes + * @payload: Payload data to be sent to the authentication firmware + */ +struct mei_lb_req { + struct mkhi_msg_hdr header; + __le32 type; + __le32 flags; + __le32 reserved[2]; + __le32 payload_size; + u8 payload[] __counted_by(payload_size); +} __packed; + +/** + * struct mei_lb_rsp - Late Binding response structure + * @header: MKHI message header (see struct mkhi_msg_hdr) + * @type: Type of the Late Binding payload + * @reserved: Reserved for future use by authentication firmware, must be set to 0 + * @status: Status returned by authentication firmware (see &enum intel_lb_status) + */ +struct mei_lb_rsp { + struct mkhi_msg_hdr header; + __le32 type; + __le32 reserved[2]; + __le32 status; +} __packed; + +static bool mei_lb_check_response(const struct device *dev, ssize_t bytes, + struct mei_lb_rsp *rsp) +{ + /* + * Received message size may be smaller than the full message size when + * reply contains only MKHI header with result field set to the error code. + * Check the header size and content first to output exact error, if needed, + * and then process to the whole message. + */ + if (bytes < sizeof(rsp->header)) { + dev_err(dev, "Received less than header size from the firmware: %zd < %zu\n", + bytes, sizeof(rsp->header)); + return false; + } + if (rsp->header.group_id != MKHI_GROUP_ID_GFX) { + dev_err(dev, "Mismatch group id: 0x%x instead of 0x%x\n", + rsp->header.group_id, MKHI_GROUP_ID_GFX); + return false; + } + if (rsp->header.command != INTEL_LB_RSP) { + dev_err(dev, "Mismatch command: 0x%x instead of 0x%x\n", + rsp->header.command, INTEL_LB_RSP); + return false; + } + if (rsp->header.result) { + dev_err(dev, "Error in result: 0x%x\n", rsp->header.result); + return false; + } + if (bytes < sizeof(*rsp)) { + dev_err(dev, "Received less than message size from the firmware: %zd < %zu\n", + bytes, sizeof(*rsp)); + return false; + } + + return true; +} + +static int mei_lb_push_payload(struct device *dev, + enum intel_lb_type type, u32 flags, + const void *payload, size_t payload_size) +{ + struct mei_cl_device *cldev; + struct mei_lb_req *req = NULL; + struct mei_lb_rsp rsp; + size_t req_size; + ssize_t bytes; + int ret; + + cldev = to_mei_cl_device(dev); + + ret = mei_cldev_enable(cldev); + if (ret) { + dev_dbg(dev, "Failed to enable firmware client. %d\n", ret); + return ret; + } + + req_size = struct_size(req, payload, payload_size); + if (req_size > mei_cldev_mtu(cldev)) { + dev_err(dev, "Payload is too big: %zu\n", payload_size); + ret = -EMSGSIZE; + goto end; + } + + req = kmalloc(req_size, GFP_KERNEL); + if (!req) { + ret = -ENOMEM; + goto end; + } + + req->header.group_id = MKHI_GROUP_ID_GFX; + req->header.command = INTEL_LB_CMD; + req->type = cpu_to_le32(type); + req->flags = cpu_to_le32(flags); + req->reserved[0] = 0; + req->reserved[1] = 0; + req->payload_size = cpu_to_le32(payload_size); + memcpy(req->payload, payload, payload_size); + + bytes = mei_cldev_send_timeout(cldev, (u8 *)req, req_size, + INTEL_LB_SEND_TIMEOUT_MSEC); + if (bytes < 0) { + dev_err(dev, "Failed to send late binding request to firmware. %zd\n", bytes); + ret = bytes; + goto end; + } + + bytes = mei_cldev_recv_timeout(cldev, (u8 *)&rsp, sizeof(rsp), + INTEL_LB_RECV_TIMEOUT_MSEC); + if (bytes < 0) { + dev_err(dev, "Failed to receive late binding reply from MEI firmware. %zd\n", + bytes); + ret = bytes; + goto end; + } + if (!mei_lb_check_response(dev, bytes, &rsp)) { + dev_err(dev, "Bad response from the firmware. header: %02x %02x %02x %02x\n", + rsp.header.group_id, rsp.header.command, + rsp.header.reserved, rsp.header.result); + ret = -EPROTO; + goto end; + } + + dev_dbg(dev, "status = %u\n", le32_to_cpu(rsp.status)); + ret = (int)le32_to_cpu(rsp.status); +end: + mei_cldev_disable(cldev); + kfree(req); + return ret; +} + +static const struct intel_lb_component_ops mei_lb_ops = { + .push_payload = mei_lb_push_payload, +}; + +static int mei_lb_component_master_bind(struct device *dev) +{ + return component_bind_all(dev, (void *)&mei_lb_ops); +} + +static void mei_lb_component_master_unbind(struct device *dev) +{ + component_unbind_all(dev, (void *)&mei_lb_ops); +} + +static const struct component_master_ops mei_lb_component_master_ops = { + .bind = mei_lb_component_master_bind, + .unbind = mei_lb_component_master_unbind, +}; + +static int mei_lb_component_match(struct device *dev, int subcomponent, + void *data) +{ + /* + * This function checks if requester is Intel %PCI_CLASS_DISPLAY_VGA or + * %PCI_CLASS_DISPLAY_OTHER device, and checks if the requester is the + * grand parent of mei_if i.e. late bind MEI device + */ + struct device *base = data; + struct pci_dev *pdev; + + if (!dev) + return 0; + + if (!dev_is_pci(dev)) + return 0; + + pdev = to_pci_dev(dev); + + if (pdev->vendor != PCI_VENDOR_ID_INTEL) + return 0; + + if (pdev->class != (PCI_CLASS_DISPLAY_VGA << 8) && + pdev->class != (PCI_CLASS_DISPLAY_OTHER << 8)) + return 0; + + if (subcomponent != INTEL_COMPONENT_LB) + return 0; + + base = base->parent; + if (!base) /* mei device */ + return 0; + + base = base->parent; /* pci device */ + + return !!base && dev == base; +} + +static int mei_lb_probe(struct mei_cl_device *cldev, + const struct mei_cl_device_id *id) +{ + struct component_match *master_match = NULL; + int ret; + + component_match_add_typed(&cldev->dev, &master_match, + mei_lb_component_match, &cldev->dev); + if (IS_ERR_OR_NULL(master_match)) + return -ENOMEM; + + ret = component_master_add_with_match(&cldev->dev, + &mei_lb_component_master_ops, + master_match); + if (ret < 0) + dev_err(&cldev->dev, "Failed to add late binding master component. %d\n", ret); + + return ret; +} + +static void mei_lb_remove(struct mei_cl_device *cldev) +{ + component_master_del(&cldev->dev, &mei_lb_component_master_ops); +} + +#define MEI_GUID_MKHI UUID_LE(0xe2c2afa2, 0x3817, 0x4d19, \ + 0x9d, 0x95, 0x6, 0xb1, 0x6b, 0x58, 0x8a, 0x5d) + +static const struct mei_cl_device_id mei_lb_tbl[] = { + { .uuid = MEI_GUID_MKHI, .version = MEI_CL_VERSION_ANY }, + { } +}; +MODULE_DEVICE_TABLE(mei, mei_lb_tbl); + +static struct mei_cl_driver mei_lb_driver = { + .id_table = mei_lb_tbl, + .name = "mei_lb", + .probe = mei_lb_probe, + .remove = mei_lb_remove, +}; + +module_mei_cl_driver(mei_lb_driver); + +MODULE_AUTHOR("Intel Corporation"); +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION("MEI Late Binding Firmware Update/Upload"); |