1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Erratas to be applied for Andes CPU cores
4 *
5 * Copyright (C) 2023 Renesas Electronics Corporation.
6 *
7 * Author: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
8 */
9
10 #include <linux/memory.h>
11 #include <linux/module.h>
12
13 #include <asm/alternative.h>
14 #include <asm/cacheflush.h>
15 #include <asm/errata_list.h>
16 #include <asm/patch.h>
17 #include <asm/processor.h>
18 #include <asm/sbi.h>
19 #include <asm/vendorid_list.h>
20
21 #define ANDESTECH_AX45MP_MARCHID 0x8000000000008a45UL
22 #define ANDESTECH_AX45MP_MIMPID 0x500UL
23 #define ANDESTECH_SBI_EXT_ANDES 0x0900031E
24
25 #define ANDES_SBI_EXT_IOCP_SW_WORKAROUND 1
26
ax45mp_iocp_sw_workaround(void)27 static long ax45mp_iocp_sw_workaround(void)
28 {
29 struct sbiret ret;
30
31 /*
32 * ANDES_SBI_EXT_IOCP_SW_WORKAROUND SBI EXT checks if the IOCP is missing and
33 * cache is controllable only then CMO will be applied to the platform.
34 */
35 ret = sbi_ecall(ANDESTECH_SBI_EXT_ANDES, ANDES_SBI_EXT_IOCP_SW_WORKAROUND,
36 0, 0, 0, 0, 0, 0);
37
38 return ret.error ? 0 : ret.value;
39 }
40
errata_probe_iocp(unsigned int stage,unsigned long arch_id,unsigned long impid)41 static void errata_probe_iocp(unsigned int stage, unsigned long arch_id, unsigned long impid)
42 {
43 static bool done;
44
45 if (!IS_ENABLED(CONFIG_ERRATA_ANDES_CMO))
46 return;
47
48 if (done)
49 return;
50
51 done = true;
52
53 if (arch_id != ANDESTECH_AX45MP_MARCHID || impid != ANDESTECH_AX45MP_MIMPID)
54 return;
55
56 if (!ax45mp_iocp_sw_workaround())
57 return;
58
59 /* Set this just to make core cbo code happy */
60 riscv_cbom_block_size = 1;
61 riscv_noncoherent_supported();
62 }
63
andes_errata_patch_func(struct alt_entry * begin,struct alt_entry * end,unsigned long archid,unsigned long impid,unsigned int stage)64 void __init_or_module andes_errata_patch_func(struct alt_entry *begin, struct alt_entry *end,
65 unsigned long archid, unsigned long impid,
66 unsigned int stage)
67 {
68 if (stage == RISCV_ALTERNATIVES_BOOT)
69 errata_probe_iocp(stage, archid, impid);
70
71 /* we have nothing to patch here ATM so just return back */
72 }
73