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From: Sergey Matyukevich <geomatsi@gmail.com>
To: linux-snps-arc@lists.infradead.org
Cc: Vineet Gupta <vgupta@kernel.org>,
	Vladimir Isaev <isaev@synopsys.com>,
	Sergey Matyukevich <geomatsi@gmail.com>,
	Sergey Matyukevich <sergey.matyukevich@synopsys.com>
Subject: [RFC PATCH 09/13] ARC: delay: elide ZOL
Date: Tue, 22 Feb 2022 17:15:02 +0300	[thread overview]
Message-ID: <20220222141506.4003433-10-geomatsi@gmail.com> (raw)
In-Reply-To: <20220222141506.4003433-1-geomatsi@gmail.com>

From: Vineet Gupta <vgupta@kernel.org>

Add __delay implementation based on DBNZ if ZOL is not supported.

Signed-off-by: Vineet Gupta <vgupta@kernel.org>
---
 arch/arc/include/asm/delay.h | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/arch/arc/include/asm/delay.h b/arch/arc/include/asm/delay.h
index 54db798f0aa0..e061d1c64f24 100644
--- a/arch/arc/include/asm/delay.h
+++ b/arch/arc/include/asm/delay.h
@@ -16,9 +16,12 @@
 
 #include <asm-generic/types.h>
 #include <asm/param.h>		/* HZ */
+#include <asm/assembler.h>
 
 extern unsigned long loops_per_jiffy;
 
+#ifndef CONFIG_ARC_LACKS_ZOL
+
 static inline void __delay(unsigned long loops)
 {
 	__asm__ __volatile__(
@@ -31,6 +34,19 @@ static inline void __delay(unsigned long loops)
         : "lp_count");
 }
 
+#else
+
+static inline void __delay(unsigned long loops)
+{
+	__asm__ __volatile__(
+	"	add   %0, %0, 1         \n"
+	"1:	nop			\n"
+	"	DBNZR %0, 1b		\n"
+	: "+r"(loops));
+}
+
+#endif
+
 extern void __bad_udelay(void);
 
 /*
-- 
2.25.1


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  parent reply	other threads:[~2022-02-22 14:15 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-02-22 14:14 [RFC PATCH 00/13] ARC: handle the lack of ZOL support Sergey Matyukevich
2022-02-22 14:14 ` [RFC PATCH 01/13] ARC: uaccess: elide unaligned handling if hardware supports Sergey Matyukevich
2022-02-22 14:14 ` [RFC PATCH 02/13] ARC: Kconfig: introduce option to disable ZOL Sergey Matyukevich
2022-02-22 14:14 ` [RFC PATCH 03/13] ARC: uaccess: drop CC_OPTIMIZE_FOR_SIZE Sergey Matyukevich
2022-02-22 14:14 ` [RFC PATCH 04/13] ARC: uaccess: elide ZOL, use double load/stores Sergey Matyukevich
2022-02-22 14:14 ` [RFC PATCH 05/13] ARCv2: memset: don't prefetch for len == 0 which happens a lot Sergey Matyukevich
2022-02-22 14:14 ` [RFC PATCH 06/13] ARCv2: memset: elide unaligned handling if hardware supports Sergey Matyukevich
2022-02-22 14:15 ` [RFC PATCH 07/13] ARCv2: memset: rewrite using double load/stores Sergey Matyukevich
2022-02-22 14:15 ` [RFC PATCH 08/13] ARC: string: use generic C code if no ZOL support Sergey Matyukevich
2022-02-22 14:15 ` Sergey Matyukevich [this message]
2022-02-22 14:15 ` [RFC PATCH 10/13] ARC: checksum: elide ZOL Sergey Matyukevich
2022-02-22 14:15 ` [RFC PATCH 11/13] ARC: head: " Sergey Matyukevich
2022-02-22 14:15 ` [RFC PATCH 12/13] ARC: build: inhibit ZOL generation by compiler Sergey Matyukevich
2022-02-22 14:15 ` [RFC PATCH 13/13] ARC: pt_regs: handle the case when ZOL is not supported Sergey Matyukevich
2022-02-28  2:09 ` [RFC PATCH 00/13] ARC: handle the lack of ZOL support Vineet Gupta
2022-03-03 19:22   ` Sergey Matyukevich
2022-03-23 10:09   ` [RFC PATCH 00/13] ARC: handle the lack of ZOL supporty Sergey Matyukevich

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