linux-kernel - [PATCH 3/3] of: address: Use dma_default_coherent to determine default coherency

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Message-Id: <20230222133712.8079-4-jiaxun.yang@flygoat.com>
Date:   Wed, 22 Feb 2023 13:37:12 +0000
From:   Jiaxun Yang <jiaxun.yang@...goat.com>
To:     linux-mips@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org,
        tsbogend@...ha.franken.de, mpe@...erman.id.au,
        paul.walmsley@...ive.com, palmer@...belt.com, robh+dt@...nel.org,
        hch@....de, m.szyprowski@...sung.com, robin.murphy@....com,
        linux-riscv@...ts.infradead.org,
        Jiaxun Yang <jiaxun.yang@...goat.com>
Subject: [PATCH 3/3] of: address: Use dma_default_coherent to determine default coherency

As for now all arches have dma_default_coherent matched with default
DMA coherency for of devices, so there is no need to have a standalone
config option.

This also fixes a case that for some MIPS platforms, coherency information
is not carried in devicetree and kernel will override dma_default_coherent
at early boot.

Note for PowerPC: CONFIG_OF_DMA_DEFUALT_COHERENT was only selected when
CONFIG_NOT_COHERENT_CACHE is false, in this case dma_default_coherent will
be true, so it still matches present behavior.

Note for RISC-V: dma_default_coherent is set to true at init code in this
series.

Signed-off-by: Jiaxun Yang <jiaxun.yang@...goat.com>
---
 arch/powerpc/Kconfig | 1 -
 arch/riscv/Kconfig   | 1 -
 drivers/of/Kconfig   | 4 ----
 drivers/of/address.c | 2 +-
 4 files changed, 1 insertion(+), 7 deletions(-)

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 2c9cdf1d8761..c67e5da714f7 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -272,7 +272,6 @@ config PPC
 	select NEED_PER_CPU_PAGE_FIRST_CHUNK	if PPC64
 	select NEED_SG_DMA_LENGTH
 	select OF
-	select OF_DMA_DEFAULT_COHERENT		if !NOT_COHERENT_CACHE
 	select OF_EARLY_FLATTREE
 	select OLD_SIGACTION			if PPC32
 	select OLD_SIGSUSPEND
diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 1d46a268ce16..406c6816d289 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -119,7 +119,6 @@ config RISCV
 	select MODULES_USE_ELF_RELA if MODULES
 	select MODULE_SECTIONS if MODULES
 	select OF
-	select OF_DMA_DEFAULT_COHERENT
 	select OF_EARLY_FLATTREE
 	select OF_IRQ
 	select PCI_DOMAINS_GENERIC if PCI
diff --git a/drivers/of/Kconfig b/drivers/of/Kconfig
index 644386833a7b..e40f10bf2ba4 100644
--- a/drivers/of/Kconfig
+++ b/drivers/of/Kconfig
@@ -102,8 +102,4 @@ config OF_OVERLAY
 config OF_NUMA
 	bool
 
-config OF_DMA_DEFAULT_COHERENT
-	# arches should select this if DMA is coherent by default for OF devices
-	bool
-
 endif # OF
diff --git a/drivers/of/address.c b/drivers/of/address.c
index 4c0b169ef9bf..23ade4919853 100644
--- a/drivers/of/address.c
+++ b/drivers/of/address.c
@@ -1103,7 +1103,7 @@ phys_addr_t __init of_dma_get_max_cpu_address(struct device_node *np)
 bool of_dma_is_coherent(struct device_node *np)
 {
 	struct device_node *node;
-	bool is_coherent = IS_ENABLED(CONFIG_OF_DMA_DEFAULT_COHERENT);
+	bool is_coherent = dma_default_coherent;
 
 	node = of_node_get(np);
 
-- 
2.37.1 (Apple Git-137.1)