linux/arch/riscv/errata/andes/errata.c
Lad Prabhakar e021ae7f51
riscv: errata: Add Andes alternative ports
Add required ports of the Alternative scheme for Andes CPU cores.

I/O Coherence Port (IOCP) provides an AXI interface for connecting external
non-caching masters, such as DMA controllers. IOCP is a specification
option and is disabled on the Renesas RZ/Five SoC due to this reason cache
management needs a software workaround.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Tested-by: Conor Dooley <conor.dooley@microchip.com> # tyre-kicking on a d1
Link: https://lore.kernel.org/r/20230818135723.80612-3-prabhakar.mahadev-lad.rj@bp.renesas.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-09-01 09:08:56 -07:00

67 lines
1.7 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* Erratas to be applied for Andes CPU cores
*
* Copyright (C) 2023 Renesas Electronics Corporation.
*
* Author: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
*/
#include <linux/memory.h>
#include <linux/module.h>
#include <asm/alternative.h>
#include <asm/cacheflush.h>
#include <asm/errata_list.h>
#include <asm/patch.h>
#include <asm/processor.h>
#include <asm/sbi.h>
#include <asm/vendorid_list.h>
#define ANDESTECH_AX45MP_MARCHID 0x8000000000008a45UL
#define ANDESTECH_AX45MP_MIMPID 0x500UL
#define ANDESTECH_SBI_EXT_ANDES 0x0900031E
#define ANDES_SBI_EXT_IOCP_SW_WORKAROUND 1
static long ax45mp_iocp_sw_workaround(void)
{
struct sbiret ret;
/*
* ANDES_SBI_EXT_IOCP_SW_WORKAROUND SBI EXT checks if the IOCP is missing and
* cache is controllable only then CMO will be applied to the platform.
*/
ret = sbi_ecall(ANDESTECH_SBI_EXT_ANDES, ANDES_SBI_EXT_IOCP_SW_WORKAROUND,
0, 0, 0, 0, 0, 0);
return ret.error ? 0 : ret.value;
}
static bool errata_probe_iocp(unsigned int stage, unsigned long arch_id, unsigned long impid)
{
if (!IS_ENABLED(CONFIG_ERRATA_ANDES_CMO))
return false;
if (arch_id != ANDESTECH_AX45MP_MARCHID || impid != ANDESTECH_AX45MP_MIMPID)
return false;
if (!ax45mp_iocp_sw_workaround())
return false;
/* Set this just to make core cbo code happy */
riscv_cbom_block_size = 1;
riscv_noncoherent_supported();
return true;
}
void __init_or_module andes_errata_patch_func(struct alt_entry *begin, struct alt_entry *end,
unsigned long archid, unsigned long impid,
unsigned int stage)
{
errata_probe_iocp(stage, archid, impid);
/* we have nothing to patch here ATM so just return back */
}