Re: [PATCH 2/3] riscv: Set dma_default_coherent to true
From: Conor Dooley <conor@kernel.org>
Date: 2023-02-22 14:51:27
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linux-mips, linux-riscv, lkml
On Wed, Feb 22, 2023 at 01:37:11PM +0000, Jiaxun Yang wrote:
quoted hunk ↗ jump to hunk
For riscv our assumption is unless a device states it is non-coherent, we take it to be DMA coherent. For devicetree probed devices that have been true since very begining with OF_DMA_DEFAULT_COHERENT selected. Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com> --- arch/riscv/kernel/setup.c | 3 +++ 1 file changed, 3 insertions(+)diff --git a/arch/riscv/kernel/setup.c b/arch/riscv/kernel/setup.c index 376d2827e736..34b371180976 100644 --- a/arch/riscv/kernel/setup.c +++ b/arch/riscv/kernel/setup.c@@ -300,6 +300,9 @@ void __init setup_arch(char **cmdline_p) riscv_init_cbom_blocksize(); riscv_fill_hwcap(); apply_boot_alternatives(); +#ifdef CONFIG_RISCV_DMA_NONCOHERENT + dma_default_coherent = true; +#endif
Do we really need to add ifdeffery for this here? It's always coherent by default, so why do we need to say set it in setup_arch() when we know that, regardless of options, it is true? Cheers, Conor.
if (IS_ENABLED(CONFIG_RISCV_ISA_ZICBOM) && riscv_isa_extension_available(NULL, ZICBOM)) riscv_noncoherent_supported(); -- 2.37.1 (Apple Git-137.1)
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