Re: [RFC v1 5/5] drm/xe/fwctl: Add System Controller FWCTL RPC handler

[Rodrigo Vivi <rodrigo.vivi@intel.com>]

On Fri, Mar 20, 2026 at 12:25:33AM -0700, Anoop, Vijay wrote:
> From: Anoop Vijay <anoop.c.vijay@intel.com>
> 
> Add FWCTL RPC handler for Xe System Controller firmware.
> 
> Implement xe_fw_ops to route FWCTL RPCs to System Controller mailbox,
> allowing userspace to issue System Controller commands via FWCTL.
> 
> Signed-off-by: Anoop Vijay <anoop.c.vijay@intel.com>
> ---
>  drivers/gpu/drm/xe/Makefile             |   1 +
>  drivers/gpu/drm/xe/abi/xe_sysctrl_abi.h |  29 +++++
>  drivers/gpu/drm/xe/xe_fwctl.c           |  10 +-
>  drivers/gpu/drm/xe/xe_sysctrl_fwctl.c   | 136 ++++++++++++++++++++++++
>  drivers/gpu/drm/xe/xe_sysctrl_mailbox.c |  31 ++++++
>  drivers/gpu/drm/xe/xe_sysctrl_mailbox.h |   2 +
>  include/uapi/fwctl/xe.h                 |  25 ++++-
>  7 files changed, 231 insertions(+), 3 deletions(-)
>  create mode 100644 drivers/gpu/drm/xe/xe_sysctrl_fwctl.c
> 
> diff --git a/drivers/gpu/drm/xe/Makefile b/drivers/gpu/drm/xe/Makefile
> index 6d47d5d59cf4..f5d7109893c8 100644
> --- a/drivers/gpu/drm/xe/Makefile
> +++ b/drivers/gpu/drm/xe/Makefile
> @@ -125,6 +125,7 @@ xe-y += xe_bb.o \
>  	xe_survivability_mode.o \
>  	xe_sync.o \
>  	xe_sysctrl.o \
> +	xe_sysctrl_fwctl.o \
>  	xe_sysctrl_mailbox.o \
>  	xe_tile.o \
>  	xe_tile_sysfs.o \
> diff --git a/drivers/gpu/drm/xe/abi/xe_sysctrl_abi.h b/drivers/gpu/drm/xe/abi/xe_sysctrl_abi.h
> index 4cbde267ac44..b80e01e8ae37 100644
> --- a/drivers/gpu/drm/xe/abi/xe_sysctrl_abi.h
> +++ b/drivers/gpu/drm/xe/abi/xe_sysctrl_abi.h
> @@ -62,4 +62,33 @@ struct xe_sysctrl_app_msg_hdr {
>  #define APP_HDR_VERSION_MASK		GENMASK(23, 16)
>  #define APP_HDR_RESERVED_MASK		GENMASK(31, 24)
>  
> +/** System Controller FSP Runtime command group */
> +#define XE_SYSCTRL_GROUP_FSP_RUNTIME    0x31
> +
> +/*
> + * XE_SYSCTRL_CMD_GET_FEATURE_CFG - Query feature configuration
> + *
> + * Return platform feature capability and configuration state.
> + *
> + * Group: XE_SYSCTRL_GROUP_FSP_RUNTIME (0x31)
> + * Command: 0x10
> + */
> +#define XE_SYSCTRL_CMD_GET_FEATURE_CFG    0x10
> +
> +/**
> + * DOC: XE_SYSCTRL_CMD_GET_FEATURE_CFG response
> + *
> + * Returns 5 DWORDs:
> + *   DW0: Supported features
> + *   DW1: Enabled features
> + *   DW2: Software-configurable features
> + *   DW3: Pending state (effective after reboot)
> + *   DW4: Default (factory) state
> + *
> + * Each DWORD is a feature bitmap.
> + */
> +#define XE_SYSCTRL_GET_FEATURE_CFG_NUM_DWORDS    5
> +#define XE_SYSCTRL_GET_FEATURE_CFG_RESP_BYTES    \
> +	(XE_SYSCTRL_GET_FEATURE_CFG_NUM_DWORDS * sizeof(__u32))
> +
>  #endif
> diff --git a/drivers/gpu/drm/xe/xe_fwctl.c b/drivers/gpu/drm/xe/xe_fwctl.c
> index 72124b5b3c87..2e8faa027487 100644
> --- a/drivers/gpu/drm/xe/xe_fwctl.c
> +++ b/drivers/gpu/drm/xe/xe_fwctl.c
> @@ -67,10 +67,12 @@
>  #include "xe_pm.h"
>  #include "xe_printk.h"
>  
> +extern const struct xe_fw_ops xe_sysctrl_fw_ops;
> +
>  DEFINE_FREE(xe_fwctl, struct xe_fwctl *, if (_T) fwctl_put(&_T->fwctl))
>  
>  static const struct xe_fw_ops *fw_ops_table[XE_FW_MAX] = {
> -	/* [XE_FW_...] = &ops, */
> +	[XE_FW_SYSCTRL] = &xe_sysctrl_fw_ops,
>  };
>  
>  static int xe_fwctl_uctx_open(struct fwctl_uctx *uctx)
> @@ -102,12 +104,16 @@ static void *xe_fwctl_info(struct fwctl_uctx *uctx, size_t *length)
>  					      fwctl);
>  	struct xe_device *xe = fwctl->xe;
>  	struct fwctl_info_xe *info;
> +	u32 fw_caps = 0;
>  
>  	info = kzalloc_obj(*info);
>  	if (!info)
>  		return ERR_PTR(-ENOMEM);
>  
> -	info->fw_caps = 0;
> +	if (xe->info.has_sysctrl && fw_ops_table[XE_FW_SYSCTRL])
> +		fw_caps |= BIT(XE_FWCTL_CAP_SYSCTRL);
> +
> +	info->fw_caps = fw_caps;
>  	info->platform = xe->info.platform;
>  
>  	*length = sizeof(*info);
> diff --git a/drivers/gpu/drm/xe/xe_sysctrl_fwctl.c b/drivers/gpu/drm/xe/xe_sysctrl_fwctl.c
> new file mode 100644
> index 000000000000..ebdbe6d1dfd8
> --- /dev/null
> +++ b/drivers/gpu/drm/xe/xe_sysctrl_fwctl.c
> @@ -0,0 +1,136 @@
> +// SPDX-License-Identifier: MIT
> +/*
> + * Copyright © 2026 Intel Corporation
> + */
> +
> +/**
> + * DOC: Xe System Controller FWCTL backend
> + *
> + * Implement FWCTL support for Xe System Controller firmware.
> + *
> + * Provide xe_fw_ops implementation to route FWCTL RPCs to System Controller
> + * mailbox using struct xe_sysctrl_rpc.
> + *
> + * validate_scope() enforces required access level for System Controller
> + * commands. rpc() executes mailbox transactions and returns responses to
> + * FWCTL core.
> + *
> + * See xe_fwctl.c for generic FWCTL documentation and userspace usage.
> + */
> +
> +#include <linux/bitfield.h>
> +#include <linux/err.h>
> +#include <linux/vmalloc.h>
> +
> +#include <uapi/fwctl/xe.h>
> +
> +#include "abi/xe_sysctrl_abi.h"
> +#include "xe_device.h"
> +#include "xe_fwctl_types.h"
> +#include "xe_sysctrl.h"
> +#include "xe_sysctrl_mailbox.h"
> +#include "xe_sysctrl_mailbox_types.h"
> +#include "xe_printk.h"
> +
> +static bool xe_sysctrl_validate_scope(void *rpc_in, size_t in_len,
> +				      enum fwctl_rpc_scope scope)
> +{
> +	struct xe_sysctrl_rpc *req = rpc_in;
> +
> +	if (in_len < sizeof(*req))
> +		return false;
> +
> +	if (req->hdr.firmware_type != XE_FW_SYSCTRL)
> +		return false;
> +
> +	switch (req->group_id) {
> +	case XE_SYSCTRL_GROUP_FSP_RUNTIME:
> +		switch (req->command) {
> +		case XE_SYSCTRL_CMD_GET_FEATURE_CFG:
> +			return scope >= FWCTL_RPC_CONFIGURATION;

The validate scope needs to explicit validate bit by bit of the API.

> +		default:
> +			return false;
> +		}
> +
> +	default:
> +		return false;
> +	}
> +}
> +
> +static void *xe_sysctrl_rpc(struct xe_device *xe,
> +			    enum fwctl_rpc_scope scope,
> +			    void *rpc_in, size_t in_len,
> +			    size_t *out_len)
> +{
> +	struct xe_sysctrl_rpc *req = rpc_in;
> +	struct xe_sysctrl_mailbox_command cmd = {};
> +	size_t in_payload, out_payload = 0;
> +	size_t expected_resp_len, resp_size;
> +	int ret;
> +
> +	if (!xe->info.has_sysctrl)
> +		return ERR_PTR(-ENODEV);
> +
> +	if (in_len < sizeof(*req))
> +		return ERR_PTR(-EINVAL);
> +
> +	if (req->hdr.firmware_type != XE_FW_SYSCTRL)
> +		return ERR_PTR(-EBADMSG);
> +
> +	in_payload = in_len - sizeof(*req);
> +	if (in_payload > XE_SYSCTRL_MB_MAX_MESSAGE_SIZE)
> +		return ERR_PTR(-EMSGSIZE);
> +
> +	ret = xe_sysctrl_get_response_len(req->group_id, req->command,
> +					  req->version, in_payload,
> +					  &expected_resp_len);
> +	if (ret)
> +		return ERR_PTR(-EOPNOTSUPP);
> +
> +	if (expected_resp_len > XE_SYSCTRL_MB_MAX_MESSAGE_SIZE)
> +		return ERR_PTR(-EMSGSIZE);
> +
> +	resp_size = sizeof(*req) + expected_resp_len;
> +	if (*out_len < resp_size)
> +		return ERR_PTR(-EMSGSIZE);
> +
> +	struct xe_sysctrl_rpc *resp __free(kvfree) = kvzalloc(resp_size, GFP_KERNEL);
> +	if (!resp)
> +		return ERR_PTR(-ENOMEM);
> +
> +	cmd.header.data = cpu_to_le32(FIELD_PREP(APP_HDR_GROUP_ID_MASK, req->group_id) |
> +				      FIELD_PREP(APP_HDR_COMMAND_MASK, req->command) |
> +				      FIELD_PREP(APP_HDR_VERSION_MASK, req->version));
> +
> +	cmd.data_in = in_payload ? req->payload : NULL;
> +	cmd.data_in_len = in_payload;
> +
> +	cmd.data_out = expected_resp_len ? resp->payload : NULL;
> +	cmd.data_out_len = expected_resp_len;
> +
> +	ret = xe_sysctrl_send_command(&xe->sc, &cmd, &out_payload);
> +	if (ret) {
> +		xe_err(xe, "sysctrl fwctl RPC failed: group=0x%02x cmd=0x%02x err=%d\n",
> +		       req->group_id, req->command, ret);
> +		return ERR_PTR(ret);
> +	}
> +
> +	if (out_payload > expected_resp_len)
> +		return ERR_PTR(-EIO);
> +
> +	resp->hdr.firmware_type = XE_FW_SYSCTRL;
> +	resp->group_id = req->group_id;
> +	resp->command  = req->command;
> +	resp->version  = req->version;
> +	resp->reserved = 0;
> +
> +	*out_len = sizeof(*resp) + out_payload;
> +
> +	return no_free_ptr(resp);
> +}
> +
> +const struct xe_fw_ops xe_sysctrl_fw_ops = {
> +	.name = "sysctrl",
> +	.rpc = xe_sysctrl_rpc,
> +	.validate_scope = xe_sysctrl_validate_scope,
> +};
> diff --git a/drivers/gpu/drm/xe/xe_sysctrl_mailbox.c b/drivers/gpu/drm/xe/xe_sysctrl_mailbox.c
> index b10c8b7e0c40..418ab672528f 100644
> --- a/drivers/gpu/drm/xe/xe_sysctrl_mailbox.c
> +++ b/drivers/gpu/drm/xe/xe_sysctrl_mailbox.c
> @@ -293,6 +293,37 @@ static int sysctrl_send_command(struct xe_sysctrl *sc,
>  	return 0;
>  }
>  
> +/**
> + * xe_sysctrl_get_response_len - Get expected response length for a command
> + * @group_id: Command group ID
> + * @command: Command ID
> + * @version: Command version
> + * @in_len: Input payload length
> + * @out_len: Pointer to store expected output length
> + *
> + * Returns: 0 on success, -EOPNOTSUPP if command is unknown
> + */
> +int xe_sysctrl_get_response_len(u8 group_id, u8 command, u8 version,
> +				size_t in_len, size_t *out_len)
> +{
> +	(void)version;
> +	(void)in_len;
> +
> +	switch (group_id) {
> +	case XE_SYSCTRL_GROUP_FSP_RUNTIME:
> +		switch (command) {
> +		case XE_SYSCTRL_CMD_GET_FEATURE_CFG:
> +			*out_len = XE_SYSCTRL_GET_FEATURE_CFG_RESP_BYTES;
> +			return 0;
> +		default:
> +			return -EOPNOTSUPP;
> +		}
> +
> +	default:
> +		return -EOPNOTSUPP;
> +	}
> +}
> +
>  /**
>   * xe_sysctrl_mailbox_init - Initialize System Controller mailbox interface
>   * @sc: System controller structure
> diff --git a/drivers/gpu/drm/xe/xe_sysctrl_mailbox.h b/drivers/gpu/drm/xe/xe_sysctrl_mailbox.h
> index 91460be9e22c..f219ad738b81 100644
> --- a/drivers/gpu/drm/xe/xe_sysctrl_mailbox.h
> +++ b/drivers/gpu/drm/xe/xe_sysctrl_mailbox.h
> @@ -23,6 +23,8 @@ struct xe_sysctrl_mailbox_command;
>  #define XE_SYSCTRL_APP_HDR_VERSION(hdr) \
>  	FIELD_GET(APP_HDR_VERSION_MASK, le32_to_cpu((hdr)->data))
>  
> +int xe_sysctrl_get_response_len(u8 group_id, u8 command, u8 version,
> +				size_t in_len, size_t *out_len);
>  void xe_sysctrl_mailbox_init(struct xe_sysctrl *sc);
>  int xe_sysctrl_send_command(struct xe_sysctrl *sc,
>  			    struct xe_sysctrl_mailbox_command *cmd,
> diff --git a/include/uapi/fwctl/xe.h b/include/uapi/fwctl/xe.h
> index 3720f188a7ec..2a1e559f94f2 100644
> --- a/include/uapi/fwctl/xe.h
> +++ b/include/uapi/fwctl/xe.h
> @@ -16,8 +16,13 @@
>   * through the kernel FWCTL framework.
>   */
>  
> +enum xe_fwctl_capabilities {
> +	XE_FWCTL_CAP_SYSCTRL = 0,
> +};
> +
>  enum xe_firmware_type {
> -	XE_FW_MAX = 1,
> +	XE_FW_SYSCTRL = 0,
> +	XE_FW_MAX,
>  };
>  
>  /**
> @@ -39,4 +44,22 @@ struct fwctl_rpc_xe {
>  	__u32 firmware_type;
>  };
>  
> +/**
> + * struct xe_sysctrl_rpc - System Controller RPC
> + * @hdr: Common Xe RPC header (firmware_type = XE_FW_SYSCTRL)
> + * @group_id: Command group identifier
> + * @command: Command code
> + * @version: Command version
> + * @reserved: Reserved for alignment, must be 0
> + * @payload: Variable-length command-specific payload
> + */
> +struct xe_sysctrl_rpc {
> +	struct fwctl_rpc_xe hdr;
> +	__u8 group_id;
> +	__u8 command;
> +	__u8 version;
> +	__u8 reserved;
> +	__u8 payload[];
> +};
> +
>  #endif
> -- 
> 2.43.0
>