// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (c) 2015-2021, Linaro Limited
 * Copyright (c) 2016, EPAM Systems
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/arm-smccc.h>
#include <linux/errno.h>
#include <linux/io.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_platform.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/tee_drv.h>
#include <linux/types.h>
#include <linux/workqueue.h>
#include "optee_private.h"
#include "optee_smc.h"
#include "optee_rpc_cmd.h"
#define CREATE_TRACE_POINTS
#include "optee_trace.h"

/*
 * This file implement the SMC ABI used when communicating with secure world
 * OP-TEE OS via raw SMCs.
 * This file is divided into the following sections:
 * 1. Convert between struct tee_param and struct optee_msg_param
 * 2. Low level support functions to register shared memory in secure world
 * 3. Dynamic shared memory pool based on alloc_pages()
 * 4. Do a normal scheduled call into secure world
 * 5. Driver initialization.
 */

#define OPTEE_SHM_NUM_PRIV_PAGES	CONFIG_OPTEE_SHM_NUM_PRIV_PAGES

/*
 * 1. Convert between struct tee_param and struct optee_msg_param
 *
 * optee_from_msg_param() and optee_to_msg_param() are the main
 * functions.
 */

static int from_msg_param_tmp_mem(struct tee_param *p, u32 attr,
				  const struct optee_msg_param *mp)
{
	struct tee_shm *shm;
	phys_addr_t pa;
	int rc;

	p->attr = TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INPUT +
		  attr - OPTEE_MSG_ATTR_TYPE_TMEM_INPUT;
	p->u.memref.size = mp->u.tmem.size;
	shm = (struct tee_shm *)(unsigned long)mp->u.tmem.shm_ref;
	if (!shm) {
		p->u.memref.shm_offs = 0;
		p->u.memref.shm = NULL;
		return 0;
	}

	rc = tee_shm_get_pa(shm, 0, &pa);
	if (rc)
		return rc;

	p->u.memref.shm_offs = mp->u.tmem.buf_ptr - pa;
	p->u.memref.shm = shm;

	/* Check that the memref is covered by the shm object */
	if (p->u.memref.size) {
		size_t o = p->u.memref.shm_offs +
			   p->u.memref.size - 1;

		rc = tee_shm_get_pa(shm, o, NULL);
		if (rc)
			return rc;
	}

	return 0;
}

static void from_msg_param_reg_mem(struct tee_param *p, u32 attr,
				   const struct optee_msg_param *mp)
{
	struct tee_shm *shm;

	p->attr = TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INPUT +
		  attr - OPTEE_MSG_ATTR_TYPE_RMEM_INPUT;
	p->u.memref.size = mp->u.rmem.size;
	shm = (struct tee_shm *)(unsigned long)mp->u.rmem.shm_ref;

	if (shm) {
		p->u.memref.shm_offs = mp->u.rmem.offs;
		p->u.memref.shm = shm;
	} else {
		p->u.memref.shm_offs = 0;
		p->u.memref.shm = NULL;
	}
}

/**
 * optee_from_msg_param() - convert from OPTEE_MSG parameters to
 *			    struct tee_param
 * @optee:	main service struct
 * @params:	subsystem internal parameter representation
 * @num_params:	number of elements in the parameter arrays
 * @msg_params:	OPTEE_MSG parameters
 * Returns 0 on success or <0 on failure
 */
static int optee_from_msg_param(struct optee *optee, struct tee_param *params,
				size_t num_params,
				const struct optee_msg_param *msg_params)
{
	int rc;
	size_t n;

	for (n = 0; n < num_params; n++) {
		struct tee_param *p = params + n;
		const struct optee_msg_param *mp = msg_params + n;
		u32 attr = mp->attr & OPTEE_MSG_ATTR_TYPE_MASK;

		switch (attr) {
		case OPTEE_MSG_ATTR_TYPE_NONE:
			p->attr = TEE_IOCTL_PARAM_ATTR_TYPE_NONE;
			memset(&p->u, 0, sizeof(p->u));
			break;
		case OPTEE_MSG_ATTR_TYPE_VALUE_INPUT:
		case OPTEE_MSG_ATTR_TYPE_VALUE_OUTPUT:
		case OPTEE_MSG_ATTR_TYPE_VALUE_INOUT:
			optee_from_msg_param_value(p, attr, mp);
			break;
		case OPTEE_MSG_ATTR_TYPE_TMEM_INPUT:
		case OPTEE_MSG_ATTR_TYPE_TMEM_OUTPUT:
		case OPTEE_MSG_ATTR_TYPE_TMEM_INOUT:
			rc = from_msg_param_tmp_mem(p, attr, mp);
			if (rc)
				return rc;
			break;
		case OPTEE_MSG_ATTR_TYPE_RMEM_INPUT:
		case OPTEE_MSG_ATTR_TYPE_RMEM_OUTPUT:
		case OPTEE_MSG_ATTR_TYPE_RMEM_INOUT:
			from_msg_param_reg_mem(p, attr, mp);
			break;

		default:
			return -EINVAL;
		}
	}
	return 0;
}

static int to_msg_param_tmp_mem(struct optee_msg_param *mp,
				const struct tee_param *p)
{
	int rc;
	phys_addr_t pa;

	mp->attr = OPTEE_MSG_ATTR_TYPE_TMEM_INPUT + p->attr -
		   TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INPUT;

	mp->u.tmem.shm_ref = (unsigned long)p->u.memref.shm;
	mp->u.tmem.size = p->u.memref.size;

	if (!p->u.memref.shm) {
		mp->u.tmem.buf_ptr = 0;
		return 0;
	}

	rc = tee_shm_get_pa(p->u.memref.shm, p->u.memref.shm_offs, &pa);
	if (rc)
		return rc;

	mp->u.tmem.buf_ptr = pa;
	mp->attr |= OPTEE_MSG_ATTR_CACHE_PREDEFINED <<
		    OPTEE_MSG_ATTR_CACHE_SHIFT;

	return 0;
}

static int to_msg_param_reg_mem(struct optee_msg_param *mp,
				const struct tee_param *p)
{
	mp->attr = OPTEE_MSG_ATTR_TYPE_RMEM_INPUT + p->attr -
		   TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INPUT;

	mp->u.rmem.shm_ref = (unsigned long)p->u.memref.shm;
	mp->u.rmem.size = p->u.memref.size;
	mp->u.rmem.offs = p->u.memref.shm_offs;
	return 0;
}

/**
 * optee_to_msg_param() - convert from struct tee_params to OPTEE_MSG parameters
 * @optee:	main service struct
 * @msg_params:	OPTEE_MSG parameters
 * @num_params:	number of elements in the parameter arrays
 * @params:	subsystem itnernal parameter representation
 * Returns 0 on success or <0 on failure
 */
static int optee_to_msg_param(struct optee *optee,
			      struct optee_msg_param *msg_params,
			      size_t num_params, const struct tee_param *params)
{
	int rc;
	size_t n;

	for (n = 0; n < num_params; n++) {
		const struct tee_param *p = params + n;
		struct optee_msg_param *mp = msg_params + n;

		switch (p->attr) {
		case TEE_IOCTL_PARAM_ATTR_TYPE_NONE:
			mp->attr = TEE_IOCTL_PARAM_ATTR_TYPE_NONE;
			memset(&mp->u, 0, sizeof(mp->u));
			break;
		case TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_INPUT:
		case TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_OUTPUT:
		case TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_INOUT:
			optee_to_msg_param_value(mp, p);
			break;
		case TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INPUT:
		case TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_OUTPUT:
		case TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INOUT:
			if (tee_shm_is_registered(p->u.memref.shm))
				rc = to_msg_param_reg_mem(mp, p);
			else
				rc = to_msg_param_tmp_mem(mp, p);
			if (rc)
				return rc;
			break;
		default:
			return -EINVAL;
		}
	}
	return 0;
}

/*
 * 2. Low level support functions to register shared memory in secure world
 *
 * Functions to enable/disable shared memory caching in secure world, that
 * is, lazy freeing of previously allocated shared memory. Freeing is
 * performed when a request has been compled.
 *
 * Functions to register and unregister shared memory both for normal
 * clients and for tee-supplicant.
 */

/**
 * optee_enable_shm_cache() - Enables caching of some shared memory allocation
 *			      in OP-TEE
 * @optee:	main service struct
 */
static void optee_enable_shm_cache(struct optee *optee)
{
	struct optee_call_waiter w;

	/* We need to retry until secure world isn't busy. */
	optee_cq_wait_init(&optee->call_queue, &w);
	while (true) {
		struct arm_smccc_res res;

		optee->smc.invoke_fn(OPTEE_SMC_ENABLE_SHM_CACHE,
				     0, 0, 0, 0, 0, 0, 0, &res);
		if (res.a0 == OPTEE_SMC_RETURN_OK)
			break;
		optee_cq_wait_for_completion(&optee->call_queue, &w);
	}
	optee_cq_wait_final(&optee->call_queue, &w);
}

/**
 * __optee_disable_shm_cache() - Disables caching of some shared memory
 *				 allocation in OP-TEE
 * @optee:	main service struct
 * @is_mapped:	true if the cached shared memory addresses were mapped by this
 *		kernel, are safe to dereference, and should be freed
 */
static void __optee_disable_shm_cache(struct optee *optee, bool is_mapped)
{
	struct optee_call_waiter w;

	/* We need to retry until secure world isn't busy. */
	optee_cq_wait_init(&optee->call_queue, &w);
	while (true) {
		union {
			struct arm_smccc_res smccc;
			struct optee_smc_disable_shm_cache_result result;
		} res;

		optee->smc.invoke_fn(OPTEE_SMC_DISABLE_SHM_CACHE,
				     0, 0, 0, 0, 0, 0, 0, &res.smccc);
		if (res.result.status == OPTEE_SMC_RETURN_ENOTAVAIL)
			break; /* All shm's freed */
		if (res.result.status == OPTEE_SMC_RETURN_OK) {
			struct tee_shm *shm;

			/*
			 * Shared memory references that were not mapped by
			 * this kernel must be ignored to prevent a crash.
			 */
			if (!is_mapped)
				continue;

			shm = reg_pair_to_ptr(res.result.shm_upper32,
					      res.result.shm_lower32);
			tee_shm_free(shm);
		} else {
			optee_cq_wait_for_completion(&optee->call_queue, &w);
		}
	}
	optee_cq_wait_final(&optee->call_queue, &w);
}

/**
 * optee_disable_shm_cache() - Disables caching of mapped shared memory
 *			       allocations in OP-TEE
 * @optee:	main service struct
 */
static void optee_disable_shm_cache(struct optee *optee)
{
	return __optee_disable_shm_cache(optee, true);
}

/**
 * optee_disable_unmapped_shm_cache() - Disables caching of shared memory
 *					allocations in OP-TEE which are not
 *					currently mapped
 * @optee:	main service struct
 */
static void optee_disable_unmapped_shm_cache(struct optee *optee)
{
	return __optee_disable_shm_cache(optee, false);
}

#define PAGELIST_ENTRIES_PER_PAGE				\
	((OPTEE_MSG_NONCONTIG_PAGE_SIZE / sizeof(u64)) - 1)

/*
 * The final entry in each pagelist page is a pointer to the next
 * pagelist page.
 */
static size_t get_pages_list_size(size_t num_entries)
{
	int pages = DIV_ROUND_UP(num_entries, PAGELIST_ENTRIES_PER_PAGE);

	return pages * OPTEE_MSG_NONCONTIG_PAGE_SIZE;
}

static u64 *optee_allocate_pages_list(size_t num_entries)
{
	return alloc_pages_exact(get_pages_list_size(num_entries), GFP_KERNEL);
}

static void optee_free_pages_list(void *list, size_t num_entries)
{
	free_pages_exact(list, get_pages_list_size(num_entries));
}

/**
 * optee_fill_pages_list() - write list of user pages to given shared
 * buffer.
 *
 * @dst: page-aligned buffer where list of pages will be stored
 * @pages: array of pages that represents shared buffer
 * @num_pages: number of entries in @pages
 * @page_offset: offset of user buffer from page start
 *
 * @dst should be big enough to hold list of user page addresses and
 *	links to the next pages of buffer
 */
static void optee_fill_pages_list(u64 *dst, struct page **pages, int num_pages,
				  size_t page_offset)
{
	int n = 0;
	phys_addr_t optee_page;
	/*
	 * Refer to OPTEE_MSG_ATTR_NONCONTIG description in optee_msg.h
	 * for details.
	 */
	struct {
		u64 pages_list[PAGELIST_ENTRIES_PER_PAGE];
		u64 next_page_data;
	} *pages_data;

	/*
	 * Currently OP-TEE uses 4k page size and it does not looks
	 * like this will change in the future.  On other hand, there are
	 * no know ARM architectures with page size < 4k.
	 * Thus the next built assert looks redundant. But the following
	 * code heavily relies on this assumption, so it is better be
	 * safe than sorry.
	 */
	BUILD_BUG_ON(PAGE_SIZE < OPTEE_MSG_NONCONTIG_PAGE_SIZE);

	pages_data = (void *)dst;
	/*
	 * If linux page is bigger than 4k, and user buffer offset is
	 * larger than 4k/8k/12k/etc this will skip first 4k pages,
	 * because they bear no value data for OP-TEE.
	 */
	optee_page = page_to_phys(*pages) +
		round_down(page_offset, OPTEE_MSG_NONCONTIG_PAGE_SIZE);

	while (true) {
		pages_data->pages_list[n++] = optee_page;

		if (n == PAGELIST_ENTRIES_PER_PAGE) {
			pages_data->next_page_data =
				virt_to_phys(pages_data + 1);
			pages_data++;
			n = 0;
		}

		optee_page += OPTEE_MSG_NONCONTIG_PAGE_SIZE;
		if (!(optee_page & ~PAGE_MASK)) {
			if (!--num_pages)
				break;
			pages++;
			optee_page = page_to_phys(*pages);
		}
	}
}

static int optee_shm_register(struct tee_context *ctx, struct tee_shm *shm,
			      struct page **pages, size_t num_pages,
			      unsigned long start)
{
	struct optee *optee = tee_get_drvdata(ctx->teedev);
	struct optee_msg_arg *msg_arg;
	struct tee_shm *shm_arg;
	u64 *pages_list;
	int rc;

	if (!num_pages)
		return -EINVAL;

	rc = optee_check_mem_type(start, num_pages);
	if (rc)
		return rc;

	pages_list = optee_allocate_pages_list(num_pages);
	if (!pages_list)
		return -ENOMEM;

	shm_arg = optee_get_msg_arg(ctx, 1, &msg_arg);
	if (IS_ERR(shm_arg)) {
		rc = PTR_ERR(shm_arg);
		goto out;
	}

	optee_fill_pages_list(pages_list, pages, num_pages,
			      tee_shm_get_page_offset(shm));

	msg_arg->cmd = OPTEE_MSG_CMD_REGISTER_SHM;
	msg_arg->params->attr = OPTEE_MSG_ATTR_TYPE_TMEM_OUTPUT |
				OPTEE_MSG_ATTR_NONCONTIG;
	msg_arg->params->u.tmem.shm_ref = (unsigned long)shm;
	msg_arg->params->u.tmem.size = tee_shm_get_size(shm);
	/*
	 * In the least bits of msg_arg->params->u.tmem.buf_ptr we
	 * store buffer offset from 4k page, as described in OP-TEE ABI.
	 */
	msg_arg->params->u.tmem.buf_ptr = virt_to_phys(pages_list) |
	  (tee_shm_get_page_offset(shm) & (OPTEE_MSG_NONCONTIG_PAGE_SIZE - 1));

	if (optee->ops->do_call_with_arg(ctx, shm_arg) ||
	    msg_arg->ret != TEEC_SUCCESS)
		rc = -EINVAL;

	tee_shm_free(shm_arg);
out:
	optee_free_pages_list(pages_list, num_pages);
	return rc;
}

static int optee_shm_unregister(struct tee_context *ctx, struct tee_shm *shm)
{
	struct optee *optee = tee_get_drvdata(ctx->teedev);
	struct optee_msg_arg *msg_arg;
	struct tee_shm *shm_arg;
	int rc = 0;

	shm_arg = optee_get_msg_arg(ctx, 1, &msg_arg);
	if (IS_ERR(shm_arg))
		return PTR_ERR(shm_arg);

	msg_arg->cmd = OPTEE_MSG_CMD_UNREGISTER_SHM;

	msg_arg->params[0].attr = OPTEE_MSG_ATTR_TYPE_RMEM_INPUT;
	msg_arg->params[0].u.rmem.shm_ref = (unsigned long)shm;

	if (optee->ops->do_call_with_arg(ctx, shm_arg) ||
	    msg_arg->ret != TEEC_SUCCESS)
		rc = -EINVAL;
	tee_shm_free(shm_arg);
	return rc;
}

static int optee_shm_register_supp(struct tee_context *ctx, struct tee_shm *shm,
				   struct page **pages, size_t num_pages,
				   unsigned long start)
{
	/*
	 * We don't want to register supplicant memory in OP-TEE.
	 * Instead information about it will be passed in RPC code.
	 */
	return optee_check_mem_type(start, num_pages);
}

static int optee_shm_unregister_supp(struct tee_context *ctx,
				     struct tee_shm *shm)
{
	return 0;
}

/*
 * 3. Dynamic shared memory pool based on alloc_pages()
 *
 * Implements an OP-TEE specific shared memory pool which is used
 * when dynamic shared memory is supported by secure world.
 *
 * The main function is optee_shm_pool_alloc_pages().
 */

static int pool_op_alloc(struct tee_shm_pool_mgr *poolm,
			 struct tee_shm *shm, size_t size)
{
	/*
	 * Shared memory private to the OP-TEE driver doesn't need
	 * to be registered with OP-TEE.
	 */
	if (shm->flags & TEE_SHM_PRIV)
		return optee_pool_op_alloc_helper(poolm, shm, size, NULL);

	return optee_pool_op_alloc_helper(poolm, shm, size, optee_shm_register);
}

static void pool_op_free(struct tee_shm_pool_mgr *poolm,
			 struct tee_shm *shm)
{
	if (!(shm->flags & TEE_SHM_PRIV))
		optee_shm_unregister(shm->ctx, shm);

	free_pages((unsigned long)shm->kaddr, get_order(shm->size));
	shm->kaddr = NULL;
}

static void pool_op_destroy_poolmgr(struct tee_shm_pool_mgr *poolm)
{
	kfree(poolm);
}

static const struct tee_shm_pool_mgr_ops pool_ops = {
	.alloc = pool_op_alloc,
	.free = pool_op_free,
	.destroy_poolmgr = pool_op_destroy_poolmgr,
};

/**
 * optee_shm_pool_alloc_pages() - create page-based allocator pool
 *
 * This pool is used when OP-TEE supports dymanic SHM. In this case
 * command buffers and such are allocated from kernel's own memory.
 */
static struct tee_shm_pool_mgr *optee_shm_pool_alloc_pages(void)
{
	struct tee_shm_pool_mgr *mgr = kzalloc(sizeof(*mgr), GFP_KERNEL);

	if (!mgr)
		return ERR_PTR(-ENOMEM);

	mgr->ops = &pool_ops;

	return mgr;
}

/*
 * 4. Do a normal scheduled call into secure world
 *
 * The function optee_smc_do_call_with_arg() performs a normal scheduled
 * call into secure world. During this call may normal world request help
 * from normal world using RPCs, Remote Procedure Calls. This includes
 * delivery of non-secure interrupts to for instance allow rescheduling of
 * the current task.
 */

static void handle_rpc_func_cmd_shm_free(struct tee_context *ctx,
					 struct optee_msg_arg *arg)
{
	struct tee_shm *shm;

	arg->ret_origin = TEEC_ORIGIN_COMMS;

	if (arg->num_params != 1 ||
	    arg->params[0].attr != OPTEE_MSG_ATTR_TYPE_VALUE_INPUT) {
		arg->ret = TEEC_ERROR_BAD_PARAMETERS;
		return;
	}

	shm = (struct tee_shm *)(unsigned long)arg->params[0].u.value.b;
	switch (arg->params[0].u.value.a) {
	case OPTEE_RPC_SHM_TYPE_APPL:
		optee_rpc_cmd_free_suppl(ctx, shm);
		break;
	case OPTEE_RPC_SHM_TYPE_KERNEL:
		tee_shm_free(shm);
		break;
	default:
		arg->ret = TEEC_ERROR_BAD_PARAMETERS;
	}
	arg->ret = TEEC_SUCCESS;
}

static void handle_rpc_func_cmd_shm_alloc(struct tee_context *ctx,
					  struct optee_msg_arg *arg,
					  struct optee_call_ctx *call_ctx)
{
	phys_addr_t pa;
	struct tee_shm *shm;
	size_t sz;
	size_t n;

	arg->ret_origin = TEEC_ORIGIN_COMMS;

	if (!arg->num_params ||
	    arg->params[0].attr != OPTEE_MSG_ATTR_TYPE_VALUE_INPUT) {
		arg->ret = TEEC_ERROR_BAD_PARAMETERS;
		return;
	}

	for (n = 1; n < arg->num_params; n++) {
		if (arg->params[n].attr != OPTEE_MSG_ATTR_TYPE_NONE) {
			arg->ret = TEEC_ERROR_BAD_PARAMETERS;
			return;
		}
	}

	sz = arg->params[0].u.value.b;
	switch (arg->params[0].u.value.a) {
	case OPTEE_RPC_SHM_TYPE_APPL:
		shm = optee_rpc_cmd_alloc_suppl(ctx, sz);
		break;
	case OPTEE_RPC_SHM_TYPE_KERNEL:
		shm = tee_shm_alloc(ctx, sz, TEE_SHM_MAPPED | TEE_SHM_PRIV);
		break;
	default:
		arg->ret = TEEC_ERROR_BAD_PARAMETERS;
		return;
	}

	if (IS_ERR(shm)) {
		arg->ret = TEEC_ERROR_OUT_OF_MEMORY;
		return;
	}

	if (tee_shm_get_pa(shm, 0, &pa)) {
		arg->ret = TEEC_ERROR_BAD_PARAMETERS;
		goto bad;
	}

	sz = tee_shm_get_size(shm);

	if (tee_shm_is_registered(shm)) {
		struct page **pages;
		u64 *pages_list;
		size_t page_num;

		pages = tee_shm_get_pages(shm, &page_num);
		if (!pages || !page_num) {
			arg->ret = TEEC_ERROR_OUT_OF_MEMORY;
			goto bad;
		}

		pages_list = optee_allocate_pages_list(page_num);
		if (!pages_list) {
			arg->ret = TEEC_ERROR_OUT_OF_MEMORY;
			goto bad;
		}

		call_ctx->pages_list = pages_list;
		call_ctx->num_entries = page_num;

		arg->params[0].attr = OPTEE_MSG_ATTR_TYPE_TMEM_OUTPUT |
				      OPTEE_MSG_ATTR_NONCONTIG;
		/*
		 * In the least bits of u.tmem.buf_ptr we store buffer offset
		 * from 4k page, as described in OP-TEE ABI.
		 */
		arg->params[0].u.tmem.buf_ptr = virt_to_phys(pages_list) |
			(tee_shm_get_page_offset(shm) &
			 (OPTEE_MSG_NONCONTIG_PAGE_SIZE - 1));
		arg->params[0].u.tmem.size = tee_shm_get_size(shm);
		arg->params[0].u.tmem.shm_ref = (unsigned long)shm;

		optee_fill_pages_list(pages_list, pages, page_num,
				      tee_shm_get_page_offset(shm));
	} else {
		arg->params[0].attr = OPTEE_MSG_ATTR_TYPE_TMEM_OUTPUT;
		arg->params[0].u.tmem.buf_ptr = pa;
		arg->params[0].u.tmem.size = sz;
		arg->params[0].u.tmem.shm_ref = (unsigned long)shm;
	}

	arg->ret = TEEC_SUCCESS;
	return;
bad:
	tee_shm_free(shm);
}

static void free_pages_list(struct optee_call_ctx *call_ctx)
{
	if (call_ctx->pages_list) {
		optee_free_pages_list(call_ctx->pages_list,
				      call_ctx->num_entries);
		call_ctx->pages_list = NULL;
		call_ctx->num_entries = 0;
	}
}

static void optee_rpc_finalize_call(struct optee_call_ctx *call_ctx)
{
	free_pages_list(call_ctx);
}

static void handle_rpc_func_cmd(struct tee_context *ctx, struct optee *optee,
				struct tee_shm *shm,
				struct optee_call_ctx *call_ctx)
{
	struct optee_msg_arg *arg;

	arg = tee_shm_get_va(shm, 0);
	if (IS_ERR(arg)) {
		pr_err("%s: tee_shm_get_va %p failed\n", __func__, shm);
		return;
	}

	switch (arg->cmd) {
	case OPTEE_RPC_CMD_SHM_ALLOC:
		free_pages_list(call_ctx);
		handle_rpc_func_cmd_shm_alloc(ctx, arg, call_ctx);
		break;
	case OPTEE_RPC_CMD_SHM_FREE:
		handle_rpc_func_cmd_shm_free(ctx, arg);
		break;
	default:
		optee_rpc_cmd(ctx, optee, arg);
	}
}

/**
 * optee_handle_rpc() - handle RPC from secure world
 * @ctx:	context doing the RPC
 * @param:	value of registers for the RPC
 * @call_ctx:	call context. Preserved during one OP-TEE invocation
 *
 * Result of RPC is written back into @param.
 */
static void optee_handle_rpc(struct tee_context *ctx,
			     struct optee_rpc_param *param,
			     struct optee_call_ctx *call_ctx)
{
	struct tee_device *teedev = ctx->teedev;
	struct optee *optee = tee_get_drvdata(teedev);
	struct tee_shm *shm;
	phys_addr_t pa;

	switch (OPTEE_SMC_RETURN_GET_RPC_FUNC(param->a0)) {
	case OPTEE_SMC_RPC_FUNC_ALLOC:
		shm = tee_shm_alloc(ctx, param->a1,
				    TEE_SHM_MAPPED | TEE_SHM_PRIV);
		if (!IS_ERR(shm) && !tee_shm_get_pa(shm, 0, &pa)) {
			reg_pair_from_64(&param->a1, &param->a2, pa);
			reg_pair_from_64(&param->a4, &param->a5,
					 (unsigned long)shm);
		} else {
			param->a1 = 0;
			param->a2 = 0;
			param->a4 = 0;
			param->a5 = 0;
		}
		break;
	case OPTEE_SMC_RPC_FUNC_FREE:
		shm = reg_pair_to_ptr(param->a1, param->a2);
		tee_shm_free(shm);
		break;
	case OPTEE_SMC_RPC_FUNC_FOREIGN_INTR:
		/*
		 * A foreign interrupt was raised while secure world was
		 * executing, since they are handled in Linux a dummy RPC is
		 * performed to let Linux take the interrupt through the normal
		 * vector.
		 */
		break;
	case OPTEE_SMC_RPC_FUNC_CMD:
		shm = reg_pair_to_ptr(param->a1, param->a2);
		handle_rpc_func_cmd(ctx, optee, shm, call_ctx);
		break;
	default:
		pr_warn("Unknown RPC func 0x%x\n",
			(u32)OPTEE_SMC_RETURN_GET_RPC_FUNC(param->a0));
		break;
	}

	param->a0 = OPTEE_SMC_CALL_RETURN_FROM_RPC;
}

/**
 * optee_smc_do_call_with_arg() - Do an SMC to OP-TEE in secure world
 * @ctx:	calling context
 * @arg:	shared memory holding the message to pass to secure world
 *
 * Does and SMC to OP-TEE in secure world and handles eventual resulting
 * Remote Procedure Calls (RPC) from OP-TEE.
 *
 * Returns return code from secure world, 0 is OK
 */
static int optee_smc_do_call_with_arg(struct tee_context *ctx,
				      struct tee_shm *arg)
{
	struct optee *optee = tee_get_drvdata(ctx->teedev);
	struct optee_call_waiter w;
	struct optee_rpc_param param = { };
	struct optee_call_ctx call_ctx = { };
	phys_addr_t parg;
	int rc;

	rc = tee_shm_get_pa(arg, 0, &parg);
	if (rc)
		return rc;

	param.a0 = OPTEE_SMC_CALL_WITH_ARG;
	reg_pair_from_64(&param.a1, &param.a2, parg);
	/* Initialize waiter */
	optee_cq_wait_init(&optee->call_queue, &w);
	while (true) {
		struct arm_smccc_res res;

		trace_optee_invoke_fn_begin(&param);
		optee->smc.invoke_fn(param.a0, param.a1, param.a2, param.a3,
				     param.a4, param.a5, param.a6, param.a7,
				     &res);
		trace_optee_invoke_fn_end(&param, &res);

		if (res.a0 == OPTEE_SMC_RETURN_ETHREAD_LIMIT) {
			/*
			 * Out of threads in secure world, wait for a thread
			 * become available.
			 */
			optee_cq_wait_for_completion(&optee->call_queue, &w);
		} else if (OPTEE_SMC_RETURN_IS_RPC(res.a0)) {
			cond_resched();
			param.a0 = res.a0;
			param.a1 = res.a1;
			param.a2 = res.a2;
			param.a3 = res.a3;
			optee_handle_rpc(ctx, &param, &call_ctx);
		} else {
			rc = res.a0;
			break;
		}
	}

	optee_rpc_finalize_call(&call_ctx);
	/*
	 * We're done with our thread in secure world, if there's any
	 * thread waiters wake up one.
	 */
	optee_cq_wait_final(&optee->call_queue, &w);

	return rc;
}

/*
 * 5. Driver initialization
 *
 * During driver inititialization is secure world probed to find out which
 * features it supports so the driver can be initialized with a matching
 * configuration. This involves for instance support for dynamic shared
 * memory instead of a static memory carvout.
 */

static void optee_get_version(struct tee_device *teedev,
			      struct tee_ioctl_version_data *vers)
{
	struct tee_ioctl_version_data v = {
		.impl_id = TEE_IMPL_ID_OPTEE,
		.impl_caps = TEE_OPTEE_CAP_TZ,
		.gen_caps = TEE_GEN_CAP_GP,
	};
	struct optee *optee = tee_get_drvdata(teedev);

	if (optee->smc.sec_caps & OPTEE_SMC_SEC_CAP_DYNAMIC_SHM)
		v.gen_caps |= TEE_GEN_CAP_REG_MEM;
	if (optee->smc.sec_caps & OPTEE_SMC_SEC_CAP_MEMREF_NULL)
		v.gen_caps |= TEE_GEN_CAP_MEMREF_NULL;
	*vers = v;
}

static int optee_smc_open(struct tee_context *ctx)
{
	struct optee *optee = tee_get_drvdata(ctx->teedev);
	u32 sec_caps = optee->smc.sec_caps;

	return optee_open(ctx, sec_caps & OPTEE_SMC_SEC_CAP_MEMREF_NULL);
}

static const struct tee_driver_ops optee_clnt_ops = {
	.get_version = optee_get_version,
	.open = optee_smc_open,
	.release = optee_release,
	.open_session = optee_open_session,
	.close_session = optee_close_session,
	.invoke_func = optee_invoke_func,
	.cancel_req = optee_cancel_req,
	.shm_register = optee_shm_register,
	.shm_unregister = optee_shm_unregister,
};

static const struct tee_desc optee_clnt_desc = {
	.name = DRIVER_NAME "-clnt",
	.ops = &optee_clnt_ops,
	.owner = THIS_MODULE,
};

static const struct tee_driver_ops optee_supp_ops = {
	.get_version = optee_get_version,
	.open = optee_smc_open,
	.release = optee_release_supp,
	.supp_recv = optee_supp_recv,
	.supp_send = optee_supp_send,
	.shm_register = optee_shm_register_supp,
	.shm_unregister = optee_shm_unregister_supp,
};

static const struct tee_desc optee_supp_desc = {
	.name = DRIVER_NAME "-supp",
	.ops = &optee_supp_ops,
	.owner = THIS_MODULE,
	.flags = TEE_DESC_PRIVILEGED,
};

static const struct optee_ops optee_ops = {
	.do_call_with_arg = optee_smc_do_call_with_arg,
	.to_msg_param = optee_to_msg_param,
	.from_msg_param = optee_from_msg_param,
};

static bool optee_msg_api_uid_is_optee_api(optee_invoke_fn *invoke_fn)
{
	struct arm_smccc_res res;

	invoke_fn(OPTEE_SMC_CALLS_UID, 0, 0, 0, 0, 0, 0, 0, &res);

	if (res.a0 == OPTEE_MSG_UID_0 && res.a1 == OPTEE_MSG_UID_1 &&
	    res.a2 == OPTEE_MSG_UID_2 && res.a3 == OPTEE_MSG_UID_3)
		return true;
	return false;
}

static void optee_msg_get_os_revision(optee_invoke_fn *invoke_fn)
{
	union {
		struct arm_smccc_res smccc;
		struct optee_smc_call_get_os_revision_result result;
	} res = {
		.result = {
			.build_id = 0
		}
	};

	invoke_fn(OPTEE_SMC_CALL_GET_OS_REVISION, 0, 0, 0, 0, 0, 0, 0,
		  &res.smccc);

	if (res.result.build_id)
		pr_info("revision %lu.%lu (%08lx)", res.result.major,
			res.result.minor, res.result.build_id);
	else
		pr_info("revision %lu.%lu", res.result.major, res.result.minor);
}

static bool optee_msg_api_revision_is_compatible(optee_invoke_fn *invoke_fn)
{
	union {
		struct arm_smccc_res smccc;
		struct optee_smc_calls_revision_result result;
	} res;

	invoke_fn(OPTEE_SMC_CALLS_REVISION, 0, 0, 0, 0, 0, 0, 0, &res.smccc);

	if (res.result.major == OPTEE_MSG_REVISION_MAJOR &&
	    (int)res.result.minor >= OPTEE_MSG_REVISION_MINOR)
		return true;
	return false;
}

static bool optee_msg_exchange_capabilities(optee_invoke_fn *invoke_fn,
					    u32 *sec_caps)
{
	union {
		struct arm_smccc_res smccc;
		struct optee_smc_exchange_capabilities_result result;
	} res;
	u32 a1 = 0;

	/*
	 * TODO This isn't enough to tell if it's UP system (from kernel
	 * point of view) or not, is_smp() returns the information
	 * needed, but can't be called directly from here.
	 */
	if (!IS_ENABLED(CONFIG_SMP) || nr_cpu_ids == 1)
		a1 |= OPTEE_SMC_NSEC_CAP_UNIPROCESSOR;

	invoke_fn(OPTEE_SMC_EXCHANGE_CAPABILITIES, a1, 0, 0, 0, 0, 0, 0,
		  &res.smccc);

	if (res.result.status != OPTEE_SMC_RETURN_OK)
		return false;

	*sec_caps = res.result.capabilities;
	return true;
}

static struct tee_shm_pool *optee_config_dyn_shm(void)
{
	struct tee_shm_pool_mgr *priv_mgr;
	struct tee_shm_pool_mgr *dmabuf_mgr;
	void *rc;

	rc = optee_shm_pool_alloc_pages();
	if (IS_ERR(rc))
		return rc;
	priv_mgr = rc;

	rc = optee_shm_pool_alloc_pages();
	if (IS_ERR(rc)) {
		tee_shm_pool_mgr_destroy(priv_mgr);
		return rc;
	}
	dmabuf_mgr = rc;

	rc = tee_shm_pool_alloc(priv_mgr, dmabuf_mgr);
	if (IS_ERR(rc)) {
		tee_shm_pool_mgr_destroy(priv_mgr);
		tee_shm_pool_mgr_destroy(dmabuf_mgr);
	}

	return rc;
}

static struct tee_shm_pool *
optee_config_shm_memremap(optee_invoke_fn *invoke_fn, void **memremaped_shm)
{
	union {
		struct arm_smccc_res smccc;
		struct optee_smc_get_shm_config_result result;
	} res;
	unsigned long vaddr;
	phys_addr_t paddr;
	size_t size;
	phys_addr_t begin;
	phys_addr_t end;
	void *va;
	struct tee_shm_pool_mgr *priv_mgr;
	struct tee_shm_pool_mgr *dmabuf_mgr;
	void *rc;
	const int sz = OPTEE_SHM_NUM_PRIV_PAGES * PAGE_SIZE;

	invoke_fn(OPTEE_SMC_GET_SHM_CONFIG, 0, 0, 0, 0, 0, 0, 0, &res.smccc);
	if (res.result.status != OPTEE_SMC_RETURN_OK) {
		pr_err("static shm service not available\n");
		return ERR_PTR(-ENOENT);
	}

	if (res.result.settings != OPTEE_SMC_SHM_CACHED) {
		pr_err("only normal cached shared memory supported\n");
		return ERR_PTR(-EINVAL);
	}

	begin = roundup(res.result.start, PAGE_SIZE);
	end = rounddown(res.result.start + res.result.size, PAGE_SIZE);
	paddr = begin;
	size = end - begin;

	if (size < 2 * OPTEE_SHM_NUM_PRIV_PAGES * PAGE_SIZE) {
		pr_err("too small shared memory area\n");
		return ERR_PTR(-EINVAL);
	}

	va = memremap(paddr, size, MEMREMAP_WB);
	if (!va) {
		pr_err("shared memory ioremap failed\n");
		return ERR_PTR(-EINVAL);
	}
	vaddr = (unsigned long)va;

	rc = tee_shm_pool_mgr_alloc_res_mem(vaddr, paddr, sz,
					    3 /* 8 bytes aligned */);
	if (IS_ERR(rc))
		goto err_memunmap;
	priv_mgr = rc;

	vaddr += sz;
	paddr += sz;
	size -= sz;

	rc = tee_shm_pool_mgr_alloc_res_mem(vaddr, paddr, size, PAGE_SHIFT);
	if (IS_ERR(rc))
		goto err_free_priv_mgr;
	dmabuf_mgr = rc;

	rc = tee_shm_pool_alloc(priv_mgr, dmabuf_mgr);
	if (IS_ERR(rc))
		goto err_free_dmabuf_mgr;

	*memremaped_shm = va;

	return rc;

err_free_dmabuf_mgr:
	tee_shm_pool_mgr_destroy(dmabuf_mgr);
err_free_priv_mgr:
	tee_shm_pool_mgr_destroy(priv_mgr);
err_memunmap:
	memunmap(va);
	return rc;
}

/* Simple wrapper functions to be able to use a function pointer */
static void optee_smccc_smc(unsigned long a0, unsigned long a1,
			    unsigned long a2, unsigned long a3,
			    unsigned long a4, unsigned long a5,
			    unsigned long a6, unsigned long a7,
			    struct arm_smccc_res *res)
{
	arm_smccc_smc(a0, a1, a2, a3, a4, a5, a6, a7, res);
}

static void optee_smccc_hvc(unsigned long a0, unsigned long a1,
			    unsigned long a2, unsigned long a3,
			    unsigned long a4, unsigned long a5,
			    unsigned long a6, unsigned long a7,
			    struct arm_smccc_res *res)
{
	arm_smccc_hvc(a0, a1, a2, a3, a4, a5, a6, a7, res);
}

static optee_invoke_fn *get_invoke_func(struct device *dev)
{
	const char *method;

	pr_info("probing for conduit method.\n");

	if (device_property_read_string(dev, "method", &method)) {
		pr_warn("missing \"method\" property\n");
		return ERR_PTR(-ENXIO);
	}

	if (!strcmp("hvc", method))
		return optee_smccc_hvc;
	else if (!strcmp("smc", method))
		return optee_smccc_smc;

	pr_warn("invalid \"method\" property: %s\n", method);
	return ERR_PTR(-EINVAL);
}

/* optee_remove - Device Removal Routine
 * @pdev: platform device information struct
 *
 * optee_remove is called by platform subsystem to alert the driver
 * that it should release the device
 */
static int optee_smc_remove(struct platform_device *pdev)
{
	struct optee *optee = platform_get_drvdata(pdev);

	/*
	 * Ask OP-TEE to free all cached shared memory objects to decrease
	 * reference counters and also avoid wild pointers in secure world
	 * into the old shared memory range.
	 */
	optee_disable_shm_cache(optee);

	optee_remove_common(optee);

	if (optee->smc.memremaped_shm)
		memunmap(optee->smc.memremaped_shm);

	kfree(optee);

	return 0;
}

/* optee_shutdown - Device Removal Routine
 * @pdev: platform device information struct
 *
 * platform_shutdown is called by the platform subsystem to alert
 * the driver that a shutdown, reboot, or kexec is happening and
 * device must be disabled.
 */
static void optee_shutdown(struct platform_device *pdev)
{
	optee_disable_shm_cache(platform_get_drvdata(pdev));
}

static int optee_probe(struct platform_device *pdev)
{
	optee_invoke_fn *invoke_fn;
	struct tee_shm_pool *pool = ERR_PTR(-EINVAL);
	struct optee *optee = NULL;
	void *memremaped_shm = NULL;
	struct tee_device *teedev;
	u32 sec_caps;
	int rc;

	invoke_fn = get_invoke_func(&pdev->dev);
	if (IS_ERR(invoke_fn))
		return PTR_ERR(invoke_fn);

	if (!optee_msg_api_uid_is_optee_api(invoke_fn)) {
		pr_warn("api uid mismatch\n");
		return -EINVAL;
	}

	optee_msg_get_os_revision(invoke_fn);

	if (!optee_msg_api_revision_is_compatible(invoke_fn)) {
		pr_warn("api revision mismatch\n");
		return -EINVAL;
	}

	if (!optee_msg_exchange_capabilities(invoke_fn, &sec_caps)) {
		pr_warn("capabilities mismatch\n");
		return -EINVAL;
	}

	/*
	 * Try to use dynamic shared memory if possible
	 */
	if (sec_caps & OPTEE_SMC_SEC_CAP_DYNAMIC_SHM)
		pool = optee_config_dyn_shm();

	/*
	 * If dynamic shared memory is not available or failed - try static one
	 */
	if (IS_ERR(pool) && (sec_caps & OPTEE_SMC_SEC_CAP_HAVE_RESERVED_SHM))
		pool = optee_config_shm_memremap(invoke_fn, &memremaped_shm);

	if (IS_ERR(pool))
		return PTR_ERR(pool);

	optee = kzalloc(sizeof(*optee), GFP_KERNEL);
	if (!optee) {
		rc = -ENOMEM;
		goto err;
	}

	optee->ops = &optee_ops;
	optee->smc.invoke_fn = invoke_fn;
	optee->smc.sec_caps = sec_caps;

	teedev = tee_device_alloc(&optee_clnt_desc, NULL, pool, optee);
	if (IS_ERR(teedev)) {
		rc = PTR_ERR(teedev);
		goto err;
	}
	optee->teedev = teedev;

	teedev = tee_device_alloc(&optee_supp_desc, NULL, pool, optee);
	if (IS_ERR(teedev)) {
		rc = PTR_ERR(teedev);
		goto err;
	}
	optee->supp_teedev = teedev;

	rc = tee_device_register(optee->teedev);
	if (rc)
		goto err;

	rc = tee_device_register(optee->supp_teedev);
	if (rc)
		goto err;

	mutex_init(&optee->call_queue.mutex);
	INIT_LIST_HEAD(&optee->call_queue.waiters);
	optee_wait_queue_init(&optee->wait_queue);
	optee_supp_init(&optee->supp);
	optee->smc.memremaped_shm = memremaped_shm;
	optee->pool = pool;

	/*
	 * Ensure that there are no pre-existing shm objects before enabling
	 * the shm cache so that there's no chance of receiving an invalid
	 * address during shutdown. This could occur, for example, if we're
	 * kexec booting from an older kernel that did not properly cleanup the
	 * shm cache.
	 */
	optee_disable_unmapped_shm_cache(optee);

	optee_enable_shm_cache(optee);

	if (optee->smc.sec_caps & OPTEE_SMC_SEC_CAP_DYNAMIC_SHM)
		pr_info("dynamic shared memory is enabled\n");

	platform_set_drvdata(pdev, optee);

	rc = optee_enumerate_devices(PTA_CMD_GET_DEVICES);
	if (rc) {
		optee_smc_remove(pdev);
		return rc;
	}

	pr_info("initialized driver\n");
	return 0;
err:
	if (optee) {
		/*
		 * tee_device_unregister() is safe to call even if the
		 * devices hasn't been registered with
		 * tee_device_register() yet.
		 */
		tee_device_unregister(optee->supp_teedev);
		tee_device_unregister(optee->teedev);
		kfree(optee);
	}
	if (pool)
		tee_shm_pool_free(pool);
	if (memremaped_shm)
		memunmap(memremaped_shm);
	return rc;
}

static const struct of_device_id optee_dt_match[] = {
	{ .compatible = "linaro,optee-tz" },
	{},
};
MODULE_DEVICE_TABLE(of, optee_dt_match);

static struct platform_driver optee_driver = {
	.probe  = optee_probe,
	.remove = optee_smc_remove,
	.shutdown = optee_shutdown,
	.driver = {
		.name = "optee",
		.of_match_table = optee_dt_match,
	},
};

int optee_smc_abi_register(void)
{
	return platform_driver_register(&optee_driver);
}

void optee_smc_abi_unregister(void)
{
	platform_driver_unregister(&optee_driver);
}