linux-kernel - [PATCH 4/6] arm64: Provide arch_sync_dma

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Message-Id: <20251219053658.84978-5-21cnbao@gmail.com>
Date: Fri, 19 Dec 2025 13:36:56 +0800
From: Barry Song <21cnbao@...il.com>
To: catalin.marinas@....com,
	m.szyprowski@...sung.com,
	robin.murphy@....com,
	will@...nel.org
Cc: ada.coupriediaz@....com,
	anshuman.khandual@....com,
	ardb@...nel.org,
	iommu@...ts.linux.dev,
	linux-arm-kernel@...ts.infradead.org,
	linux-kernel@...r.kernel.org,
	maz@...nel.org,
	ryan.roberts@....com,
	surenb@...gle.com,
	v-songbaohua@...o.com,
	zhengtangquan@...o.com
Subject: [PATCH 4/6] arm64: Provide arch_sync_dma_ batched helpers

From: Barry Song <v-songbaohua@...o.com>

arch_sync_dma_for_device_batch_add() and
arch_sync_dma_for_cpu_batch_add() batch DMA sync operations,
while arch_sync_dma_batch_flush() waits for their completion
as a group.

On architectures that do not support batching,
arch_sync_dma_for_device_batch_add() and
arch_sync_dma_for_cpu_batch_add() fall back to the non-batched
implementations, and arch_sync_dma_batch_flush() is a no-op.

Cc: Catalin Marinas <catalin.marinas@....com>
Cc: Will Deacon <will@...nel.org>
Cc: Marek Szyprowski <m.szyprowski@...sung.com>
Cc: Robin Murphy <robin.murphy@....com>
Cc: Ada Couprie Diaz <ada.coupriediaz@....com>
Cc: Ard Biesheuvel <ardb@...nel.org>
Cc: Marc Zyngier <maz@...nel.org>
Cc: Anshuman Khandual <anshuman.khandual@....com>
Cc: Ryan Roberts <ryan.roberts@....com>
Cc: Suren Baghdasaryan <surenb@...gle.com>
Cc: Tangquan Zheng <zhengtangquan@...o.com>
Signed-off-by: Barry Song <v-songbaohua@...o.com>
---
 arch/arm64/Kconfig          |  1 +
 arch/arm64/mm/dma-mapping.c | 24 ++++++++++++++++++++++++
 include/linux/dma-map-ops.h | 22 ++++++++++++++++++++++
 kernel/dma/Kconfig          |  3 +++
 4 files changed, 50 insertions(+)

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 93173f0a09c7..c8adbf21b7bf 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -112,6 +112,7 @@ config ARM64
 	select ARCH_SUPPORTS_SCHED_CLUSTER
 	select ARCH_SUPPORTS_SCHED_MC
 	select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
+	select ARCH_WANT_BATCHED_DMA_SYNC
 	select ARCH_WANT_COMPAT_IPC_PARSE_VERSION if COMPAT
 	select ARCH_WANT_DEFAULT_BPF_JIT
 	select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT
diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c
index b2b5792b2caa..9ac1ddd1bb9c 100644
--- a/arch/arm64/mm/dma-mapping.c
+++ b/arch/arm64/mm/dma-mapping.c
@@ -31,6 +31,30 @@ void arch_sync_dma_for_cpu(phys_addr_t paddr, size_t size,
 	dcache_inval_poc(start, start + size);
 }
 
+void arch_sync_dma_for_device_batch_add(phys_addr_t paddr, size_t size,
+			      enum dma_data_direction dir)
+{
+	unsigned long start = (unsigned long)phys_to_virt(paddr);
+
+	dcache_clean_poc_nosync(start, start + size);
+}
+
+void arch_sync_dma_for_cpu_batch_add(phys_addr_t paddr, size_t size,
+			   enum dma_data_direction dir)
+{
+	unsigned long start = (unsigned long)phys_to_virt(paddr);
+
+	if (dir == DMA_TO_DEVICE)
+		return;
+
+	dcache_inval_poc_nosync(start, start + size);
+}
+
+void arch_sync_dma_batch_flush(void)
+{
+	dsb(sy);
+}
+
 void arch_dma_prep_coherent(struct page *page, size_t size)
 {
 	unsigned long start = (unsigned long)page_address(page);
diff --git a/include/linux/dma-map-ops.h b/include/linux/dma-map-ops.h
index 4809204c674c..5ee92c410e3c 100644
--- a/include/linux/dma-map-ops.h
+++ b/include/linux/dma-map-ops.h
@@ -361,6 +361,28 @@ static inline void arch_sync_dma_for_cpu(phys_addr_t paddr, size_t size,
 }
 #endif /* ARCH_HAS_SYNC_DMA_FOR_CPU */
 
+#ifdef CONFIG_ARCH_WANT_BATCHED_DMA_SYNC
+void arch_sync_dma_for_device_batch_add(phys_addr_t paddr, size_t size,
+		enum dma_data_direction dir);
+void arch_sync_dma_for_cpu_batch_add(phys_addr_t paddr, size_t size,
+		enum dma_data_direction dir);
+void arch_sync_dma_batch_flush(void);
+#else
+static inline void arch_sync_dma_for_device_batch_add(phys_addr_t paddr, size_t size,
+		enum dma_data_direction dir)
+{
+	arch_sync_dma_for_device(paddr, size, dir);
+}
+static inline void arch_sync_dma_for_cpu_batch_add(phys_addr_t paddr, size_t size,
+		enum dma_data_direction dir)
+{
+	arch_sync_dma_for_cpu(paddr, size, dir);
+}
+static inline void arch_sync_dma_batch_flush(void)
+{
+}
+#endif
+
 #ifdef CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU_ALL
 void arch_sync_dma_for_cpu_all(void);
 #else
diff --git a/kernel/dma/Kconfig b/kernel/dma/Kconfig
index 31cfdb6b4bc3..2785099b2fa0 100644
--- a/kernel/dma/Kconfig
+++ b/kernel/dma/Kconfig
@@ -78,6 +78,9 @@ config ARCH_HAS_DMA_PREP_COHERENT
 config ARCH_HAS_FORCE_DMA_UNENCRYPTED
 	bool
 
+config ARCH_WANT_BATCHED_DMA_SYNC
+	bool
+
 #
 # Select this option if the architecture assumes DMA devices are coherent
 # by default.
-- 
2.39.3 (Apple Git-146)