xref: /openbmc/u-boot/arch/arm/mach-meson/sm.c (revision 9450ab2b)
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * (C) Copyright 2016 Beniamino Galvani <b.galvani@gmail.com>
4  *
5  * Secure monitor calls.
6  */
7 
8 #include <common.h>
9 #include <linux/kernel.h>
10 
11 #define FN_GET_SHARE_MEM_INPUT_BASE	0x82000020
12 #define FN_GET_SHARE_MEM_OUTPUT_BASE	0x82000021
13 #define FN_EFUSE_READ			0x82000030
14 #define FN_EFUSE_WRITE			0x82000031
15 
16 static void *shmem_input;
17 static void *shmem_output;
18 
meson_init_shmem(void)19 static void meson_init_shmem(void)
20 {
21 	struct pt_regs regs;
22 
23 	if (shmem_input && shmem_output)
24 		return;
25 
26 	regs.regs[0] = FN_GET_SHARE_MEM_INPUT_BASE;
27 	smc_call(&regs);
28 	shmem_input = (void *)regs.regs[0];
29 
30 	regs.regs[0] = FN_GET_SHARE_MEM_OUTPUT_BASE;
31 	smc_call(&regs);
32 	shmem_output = (void *)regs.regs[0];
33 
34 	debug("Secure Monitor shmem: 0x%p 0x%p\n", shmem_input, shmem_output);
35 }
36 
meson_sm_read_efuse(uintptr_t offset,void * buffer,size_t size)37 ssize_t meson_sm_read_efuse(uintptr_t offset, void *buffer, size_t size)
38 {
39 	struct pt_regs regs;
40 
41 	meson_init_shmem();
42 
43 	regs.regs[0] = FN_EFUSE_READ;
44 	regs.regs[1] = offset;
45 	regs.regs[2] = size;
46 
47 	smc_call(&regs);
48 
49 	if (regs.regs[0] == 0)
50 		return -1;
51 
52 	memcpy(buffer, shmem_output, min(size, regs.regs[0]));
53 
54 	return regs.regs[0];
55 }
56