linux/drivers/firmware/qcom/qcom_scm-legacy.c

// SPDX-License-Identifier: GPL-2.0-only
/* Copyright (c) 2010,2015,2019 The Linux Foundation. All rights reserved.
 * Copyright (C) 2015 Linaro Ltd.
 */

#include <linux/slab.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/errno.h>
#include <linux/err.h>
#include <linux/firmware/qcom/qcom_scm.h>
#include <linux/arm-smccc.h>
#include <linux/dma-mapping.h>

#include "qcom_scm.h"

static DEFINE_MUTEX(qcom_scm_lock);


/**
 * struct arm_smccc_args
 * @args:	The array of values used in registers in smc instruction
 */
struct arm_smccc_args { … };


/**
 * struct scm_legacy_command - one SCM command buffer
 * @len: total available memory for command and response
 * @buf_offset: start of command buffer
 * @resp_hdr_offset: start of response buffer
 * @id: command to be executed
 * @buf: buffer returned from scm_legacy_get_command_buffer()
 *
 * An SCM command is laid out in memory as follows:
 *
 *	------------------- <--- struct scm_legacy_command
 *	| command header  |
 *	------------------- <--- scm_legacy_get_command_buffer()
 *	| command buffer  |
 *	------------------- <--- struct scm_legacy_response and
 *	| response header |      scm_legacy_command_to_response()
 *	------------------- <--- scm_legacy_get_response_buffer()
 *	| response buffer |
 *	-------------------
 *
 * There can be arbitrary padding between the headers and buffers so
 * you should always use the appropriate scm_legacy_get_*_buffer() routines
 * to access the buffers in a safe manner.
 */
struct scm_legacy_command { … };

/**
 * struct scm_legacy_response - one SCM response buffer
 * @len: total available memory for response
 * @buf_offset: start of response data relative to start of scm_legacy_response
 * @is_complete: indicates if the command has finished processing
 */
struct scm_legacy_response { … };

/**
 * scm_legacy_command_to_response() - Get a pointer to a scm_legacy_response
 * @cmd: command
 *
 * Returns a pointer to a response for a command.
 */
static inline struct scm_legacy_response *scm_legacy_command_to_response(
		const struct scm_legacy_command *cmd)
{ … }

/**
 * scm_legacy_get_command_buffer() - Get a pointer to a command buffer
 * @cmd: command
 *
 * Returns a pointer to the command buffer of a command.
 */
static inline void *scm_legacy_get_command_buffer(
		const struct scm_legacy_command *cmd)
{ … }

/**
 * scm_legacy_get_response_buffer() - Get a pointer to a response buffer
 * @rsp: response
 *
 * Returns a pointer to a response buffer of a response.
 */
static inline void *scm_legacy_get_response_buffer(
		const struct scm_legacy_response *rsp)
{ … }

static void __scm_legacy_do(const struct arm_smccc_args *smc,
			    struct arm_smccc_res *res)
{ … }

/**
 * scm_legacy_call() - Sends a command to the SCM and waits for the command to
 * finish processing.
 * @dev:	device
 * @desc:	descriptor structure containing arguments and return values
 * @res:        results from SMC call
 *
 * A note on cache maintenance:
 * Note that any buffers that are expected to be accessed by the secure world
 * must be flushed before invoking qcom_scm_call and invalidated in the cache
 * immediately after qcom_scm_call returns. Cache maintenance on the command
 * and response buffers is taken care of by qcom_scm_call; however, callers are
 * responsible for any other cached buffers passed over to the secure world.
 */
int scm_legacy_call(struct device *dev, const struct qcom_scm_desc *desc,
		    struct qcom_scm_res *res)
{ … }

#define SCM_LEGACY_ATOMIC_N_REG_ARGS …
#define SCM_LEGACY_ATOMIC_FIRST_REG_IDX …
#define SCM_LEGACY_CLASS_REGISTER …
#define SCM_LEGACY_MASK_IRQS …
#define SCM_LEGACY_ATOMIC_ID(svc, cmd, n) …

/**
 * scm_legacy_call_atomic() - Send an atomic SCM command with up to 5 arguments
 * and 3 return values
 * @unused: device, legacy argument, not used, can be NULL
 * @desc: SCM call descriptor containing arguments
 * @res:  SCM call return values
 *
 * This shall only be used with commands that are guaranteed to be
 * uninterruptable, atomic and SMP safe.
 */
int scm_legacy_call_atomic(struct device *unused,
			   const struct qcom_scm_desc *desc,
			   struct qcom_scm_res *res)
{ … }