arch/riscv/errata/andes/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/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
  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
  41 static bool errata_probe_iocp(unsigned int stage, unsigned long arch_id, unsigned long impid)
  42 {
  43         if (!IS_ENABLED(CONFIG_ERRATA_ANDES_CMO))
  44                 return false;
  45
  46         if (arch_id != ANDESTECH_AX45MP_MARCHID || impid != ANDESTECH_AX45MP_MIMPID)
  47                 return false;
  48
  49         if (!ax45mp_iocp_sw_workaround())
  50                 return false;
  51
  52         /* Set this just to make core cbo code happy */
  53         riscv_cbom_block_size = 1;
  54         riscv_noncoherent_supported();
  55
  56         return true;
  57 }
  58
  59 void __init_or_module andes_errata_patch_func(struct alt_entry *begin, struct alt_entry *end,
  60                                               unsigned long archid, unsigned long impid,
  61                                               unsigned int stage)
  62 {
  63         errata_probe_iocp(stage, archid, impid);
  64
  65         /* we have nothing to patch here ATM so just return back */
  66 }