linux/arch/riscv/include/asm/cache.h
Heiko Stuebner 1631ba1259
riscv: Add support for non-coherent devices using zicbom extension
The Zicbom ISA-extension was ratified in november 2021
and introduces instructions for dcache invalidate, clean
and flush operations.

Implement cache management operations for non-coherent devices
based on them.

Of course not all cores will support this, so implement an
alternative-based mechanism that replaces empty instructions
with ones done around Zicbom instructions.

As discussed in previous versions, assume the platform
being coherent by default so that non-coherent devices need
to get marked accordingly by firmware.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Reviewed-by: Guo Ren <guoren@kernel.org>
Link: https://lore.kernel.org/r/20220706231536.2041855-4-heiko@sntech.de
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2022-07-28 15:30:51 -07:00

27 lines
601 B
C

/* SPDX-License-Identifier: GPL-2.0-only */
/*
* Copyright (C) 2017 Chen Liqin <liqin.chen@sunplusct.com>
* Copyright (C) 2012 Regents of the University of California
*/
#ifndef _ASM_RISCV_CACHE_H
#define _ASM_RISCV_CACHE_H
#define L1_CACHE_SHIFT 6
#define L1_CACHE_BYTES (1 << L1_CACHE_SHIFT)
#ifdef CONFIG_RISCV_DMA_NONCOHERENT
#define ARCH_DMA_MINALIGN L1_CACHE_BYTES
#endif
/*
* RISC-V requires the stack pointer to be 16-byte aligned, so ensure that
* the flat loader aligns it accordingly.
*/
#ifndef CONFIG_MMU
#define ARCH_SLAB_MINALIGN 16
#endif
#endif /* _ASM_RISCV_CACHE_H */