1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (C) 2021 Heiko Stuebner <heiko@sntech.de>
4  */
5 
6 #include <linux/bug.h>
7 #include <linux/kernel.h>
8 #include <linux/module.h>
9 #include <linux/string.h>
10 #include <linux/uaccess.h>
11 #include <asm/alternative.h>
12 #include <asm/cacheflush.h>
13 #include <asm/errata_list.h>
14 #include <asm/patch.h>
15 #include <asm/vendorid_list.h>
16 
errata_probe_pbmt(unsigned int stage,unsigned long arch_id,unsigned long impid)17 static bool errata_probe_pbmt(unsigned int stage,
18 			      unsigned long arch_id, unsigned long impid)
19 {
20 	if (!IS_ENABLED(CONFIG_ERRATA_THEAD_PBMT))
21 		return false;
22 
23 	if (arch_id != 0 || impid != 0)
24 		return false;
25 
26 	if (stage == RISCV_ALTERNATIVES_EARLY_BOOT ||
27 	    stage == RISCV_ALTERNATIVES_MODULE)
28 		return true;
29 
30 	return false;
31 }
32 
errata_probe_cmo(unsigned int stage,unsigned long arch_id,unsigned long impid)33 static bool errata_probe_cmo(unsigned int stage,
34 			     unsigned long arch_id, unsigned long impid)
35 {
36 	if (!IS_ENABLED(CONFIG_ERRATA_THEAD_CMO))
37 		return false;
38 
39 	if (arch_id != 0 || impid != 0)
40 		return false;
41 
42 	if (stage == RISCV_ALTERNATIVES_EARLY_BOOT)
43 		return false;
44 
45 	riscv_cbom_block_size = L1_CACHE_BYTES;
46 	riscv_noncoherent_supported();
47 	return true;
48 }
49 
thead_errata_probe(unsigned int stage,unsigned long archid,unsigned long impid)50 static u32 thead_errata_probe(unsigned int stage,
51 			      unsigned long archid, unsigned long impid)
52 {
53 	u32 cpu_req_errata = 0;
54 
55 	if (errata_probe_pbmt(stage, archid, impid))
56 		cpu_req_errata |= BIT(ERRATA_THEAD_PBMT);
57 
58 	if (errata_probe_cmo(stage, archid, impid))
59 		cpu_req_errata |= BIT(ERRATA_THEAD_CMO);
60 
61 	return cpu_req_errata;
62 }
63 
thead_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 thead_errata_patch_func(struct alt_entry *begin, struct alt_entry *end,
65 					      unsigned long archid, unsigned long impid,
66 					      unsigned int stage)
67 {
68 	struct alt_entry *alt;
69 	u32 cpu_req_errata = thead_errata_probe(stage, archid, impid);
70 	u32 tmp;
71 
72 	for (alt = begin; alt < end; alt++) {
73 		if (alt->vendor_id != THEAD_VENDOR_ID)
74 			continue;
75 		if (alt->errata_id >= ERRATA_THEAD_NUMBER)
76 			continue;
77 
78 		tmp = (1U << alt->errata_id);
79 		if (cpu_req_errata & tmp) {
80 			/* On vm-alternatives, the mmu isn't running yet */
81 			if (stage == RISCV_ALTERNATIVES_EARLY_BOOT)
82 				memcpy((void *)__pa_symbol(alt->old_ptr),
83 				       (void *)__pa_symbol(alt->alt_ptr), alt->alt_len);
84 			else
85 				patch_text_nosync(alt->old_ptr, alt->alt_ptr, alt->alt_len);
86 		}
87 	}
88 
89 	if (stage == RISCV_ALTERNATIVES_EARLY_BOOT)
90 		local_flush_icache_all();
91 }
92