From 02c4be2f3f7ab54cb6e896aa80a2055b37313080 Mon Sep 17 00:00:00 2001
From: Shaokun Zhang <zhangshaokun@hisilicon.com>
Date: Wed, 5 Jun 2019 15:11:20 +0800
Subject: [PATCH] arm64: cacheinfo: Update cache_line_size detected from DT or
 PPTT

mainline inclusion
from mainline-v5.2
commit: 7b8c87b297a7c1b3badabc1d054b6e0b758952df
category: performance
bugzilla: NA
CVE: NA

--------------------------------------------------

Add coherency_max_size variable to record the maximum cache line size
cache_line_size is derived from CTR_EL0.CWG field and is called mostly
for I/O device drivers. For some platforms like the HiSilicon Kunpeng920
server SoC, cache line sizes are different between L1/2 cache and L3
cache while L1 cache line size is 64-byte and L3 is 128-byte, but
CTR_EL0.CWG is misreporting using L1 cache line size.

We shall correct the right value which is important for I/O performance.
Let's update the cache line size if it is detected from DT or PPTT
information.

Cc: Will Deacon <will.deacon@arm.com>
Cc: Jeremy Linton <jeremy.linton@arm.com>
Cc: Zhenfa Qiu <qiuzhenfa@hisilicon.com>
Reported-by: Zhenfa Qiu <qiuzhenfa@hisilicon.com>
Suggested-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Shaokun Zhang <zhangshaokun@hisilicon.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Shaokun Zhang <zhangshaokun@hisilicon.com>
Reviewed-by: Xie XiuQi <xiexiuqi@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
---
 arch/arm64/include/asm/cache.h |  6 +-----
 arch/arm64/kernel/cacheinfo.c  | 11 +++++++++++
 2 files changed, 12 insertions(+), 5 deletions(-)

diff --git a/arch/arm64/include/asm/cache.h b/arch/arm64/include/asm/cache.h
index 13dd42c3ad4e..1c1485f669ea 100644
--- a/arch/arm64/include/asm/cache.h
+++ b/arch/arm64/include/asm/cache.h
@@ -87,11 +87,7 @@ static inline u32 cache_type_cwg(void)
 
 #define __read_mostly __attribute__((__section__(".data..read_mostly")))
 
-static inline int cache_line_size(void)
-{
-	u32 cwg = cache_type_cwg();
-	return cwg ? 4 << cwg : ARCH_DMA_MINALIGN;
-}
+int cache_line_size(void);
 
 /*
  * Read the effective value of CTR_EL0.
diff --git a/arch/arm64/kernel/cacheinfo.c b/arch/arm64/kernel/cacheinfo.c
index 0bf0a835122f..0c0cd4d26b87 100644
--- a/arch/arm64/kernel/cacheinfo.c
+++ b/arch/arm64/kernel/cacheinfo.c
@@ -28,6 +28,17 @@
 #define CLIDR_CTYPE(clidr, level)	\
 	(((clidr) & CLIDR_CTYPE_MASK(level)) >> CLIDR_CTYPE_SHIFT(level))
 
+int cache_line_size(void)
+{
+	u32 cwg = cache_type_cwg();
+
+	if (coherency_max_size != 0)
+		return coherency_max_size;
+
+	return cwg ? 4 << cwg : ARCH_DMA_MINALIGN;
+}
+EXPORT_SYMBOL_GPL(cache_line_size);
+
 static inline enum cache_type get_cache_type(int level)
 {
 	u64 clidr;
-- 
GitLab