[RFC PATCH 2/5] arm64: Provide dcache_clean_poc_nosync helper

[Barry Song <21cnbao@gmail.com>]

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

dcache_clean_poc_nosync does not wait for the data cache clean to
complete. Later, we wait for completion of all scatter-gather entries
together.

Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Ada Couprie Diaz <ada.coupriediaz@arm.com>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Tangquan Zheng <zhengtangquan@oppo.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Cc: iommu@lists.linux.dev
Signed-off-by: Barry Song <v-songbaohua@oppo.com>
---
 arch/arm64/include/asm/cacheflush.h |  1 +
 arch/arm64/mm/cache.S               | 15 +++++++++++++++
 2 files changed, 16 insertions(+)

diff --git a/arch/arm64/include/asm/cacheflush.h b/arch/arm64/include/asm/cacheflush.h
index 28ab96e808ef..9b6d0a62cf3d 100644
--- a/arch/arm64/include/asm/cacheflush.h
+++ b/arch/arm64/include/asm/cacheflush.h
@@ -74,6 +74,7 @@ extern void icache_inval_pou(unsigned long start, unsigned long end);
 extern void dcache_clean_inval_poc(unsigned long start, unsigned long end);
 extern void dcache_inval_poc(unsigned long start, unsigned long end);
 extern void dcache_clean_poc(unsigned long start, unsigned long end);
+extern void dcache_clean_poc_nosync(unsigned long start, unsigned long end);
 extern void dcache_clean_pop(unsigned long start, unsigned long end);
 extern void dcache_clean_pou(unsigned long start, unsigned long end);
 extern long caches_clean_inval_user_pou(unsigned long start, unsigned long end);
diff --git a/arch/arm64/mm/cache.S b/arch/arm64/mm/cache.S
index 503567c864fd..4a7c7e03785d 100644
--- a/arch/arm64/mm/cache.S
+++ b/arch/arm64/mm/cache.S
@@ -178,6 +178,21 @@ SYM_FUNC_START(__pi_dcache_clean_poc)
 SYM_FUNC_END(__pi_dcache_clean_poc)
 SYM_FUNC_ALIAS(dcache_clean_poc, __pi_dcache_clean_poc)
 
+/*
+ *	dcache_clean_poc_nosync(start, end)
+ *
+ * 	Issue the instructions of D-cache lines for the interval [start, end).
+ * 	not necessarily cleaned to the PoC till an explicit dsb sy afterward.
+ *
+ *	- start   - virtual start address of region
+ *	- end     - virtual end address of region
+ */
+SYM_FUNC_START(__pi_dcache_clean_poc_nosync)
+	dcache_by_line_op_nosync cvac, x0, x1, x2, x3
+	ret
+SYM_FUNC_END(__pi_dcache_clean_poc_nosync)
+SYM_FUNC_ALIAS(dcache_clean_poc_nosync, __pi_dcache_clean_poc_nosync)
+
 /*
  *	dcache_clean_pop(start, end)
  *
-- 
2.39.3 (Apple Git-146)