1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Copyright (C) 2022, Microchip
4  */
5 
6 #include <linux/arm-smccc.h>
7 #include <linux/of.h>
8 
9 #include "sam_secure.h"
10 
11 static bool optee_available;
12 
13 #define SAM_SIP_SMC_STD_CALL_VAL(func_num) \
14 	ARM_SMCCC_CALL_VAL(ARM_SMCCC_STD_CALL, ARM_SMCCC_SMC_32, \
15 	ARM_SMCCC_OWNER_SIP, (func_num))
16 
sam_smccc_call(u32 fn,u32 arg0,u32 arg1)17 struct arm_smccc_res sam_smccc_call(u32 fn, u32 arg0, u32 arg1)
18 {
19 	struct arm_smccc_res res = {.a0 = -1};
20 
21 	if (WARN_ON(!optee_available))
22 		return res;
23 
24 	arm_smccc_smc(SAM_SIP_SMC_STD_CALL_VAL(fn), arg0, arg1, 0, 0, 0, 0, 0,
25 		      &res);
26 
27 	return res;
28 }
29 
sam_linux_is_optee_available(void)30 bool sam_linux_is_optee_available(void)
31 {
32 	/* If optee has been detected, then we are running in normal world */
33 	return optee_available;
34 }
35 
sam_secure_init(void)36 void __init sam_secure_init(void)
37 {
38 	struct device_node *np;
39 
40 	/*
41 	 * We only check that the OP-TEE node is present and available. The
42 	 * OP-TEE kernel driver is not needed for the type of interaction made
43 	 * with OP-TEE here so the driver's status is not checked.
44 	 */
45 	np = of_find_node_by_path("/firmware/optee");
46 	if (np && of_device_is_available(np))
47 		optee_available = true;
48 	of_node_put(np);
49 
50 	if (optee_available)
51 		pr_info("Running under OP-TEE firmware\n");
52 }
53