errata.c

 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/text-patching.h>
17#include <asm/processor.h>
18#include <asm/sbi.h>
19#include <asm/vendorid_list.h>
20#include <asm/vendor_extensions.h>
21
22#define ANDES_AX45MP_MARCHID		0x8000000000008a45UL
23#define ANDES_AX45MP_MIMPID		0x500UL
24#define ANDES_SBI_EXT_ANDES		0x0900031E
25
26#define ANDES_SBI_EXT_IOCP_SW_WORKAROUND	1
27
28static long ax45mp_iocp_sw_workaround(void)
29{
30	struct sbiret ret;
31
32	/*
33	 * ANDES_SBI_EXT_IOCP_SW_WORKAROUND SBI EXT checks if the IOCP is missing and
34	 * cache is controllable only then CMO will be applied to the platform.
35	 */
36	ret = sbi_ecall(ANDES_SBI_EXT_ANDES, ANDES_SBI_EXT_IOCP_SW_WORKAROUND,
37			0, 0, 0, 0, 0, 0);
38
39	return ret.error ? 0 : ret.value;
40}
41
42static void errata_probe_iocp(unsigned int stage, unsigned long arch_id, unsigned long impid)
43{
44	static bool done;
45
46	if (!IS_ENABLED(CONFIG_ERRATA_ANDES_CMO))
47		return;
48
49	if (done)
50		return;
51
52	done = true;
53
54	if (arch_id != ANDES_AX45MP_MARCHID || impid != ANDES_AX45MP_MIMPID)
55		return;
56
57	if (!ax45mp_iocp_sw_workaround())
58		return;
59
60	/* Set this just to make core cbo code happy */
61	riscv_cbom_block_size = 1;
62	riscv_noncoherent_supported();
63}
64
65void __init_or_module andes_errata_patch_func(struct alt_entry *begin, struct alt_entry *end,
66					      unsigned long archid, unsigned long impid,
67					      unsigned int stage)
68{
69	BUILD_BUG_ON(ERRATA_ANDES_NUMBER >= RISCV_VENDOR_EXT_ALTERNATIVES_BASE);
70
71	if (stage == RISCV_ALTERNATIVES_BOOT)
72		errata_probe_iocp(stage, archid, impid);
73
74	/* we have nothing to patch here ATM so just return back */
75}