[PATCH 09/17] riscv: improve the default power off implementation

From: Christoph Hellwig <hch@lst.de>
To: Palmer Dabbelt <palmer@sifive.com>
Cc: linux-mm@kvack.org, Damien Le Moal <damien.lemoal@wdc.com>,
	linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org,
	uclinux-dev@uclinux.org
Subject: [PATCH 09/17] riscv: improve the default power off implementation
Date: Tue, 11 Jun 2019 00:16:13 +0200	[thread overview]
Message-ID: <20190610221621.10938-10-hch@lst.de> (raw)
In-Reply-To: <20190610221621.10938-1-hch@lst.de>

Only call the SBI code if we are not running in M mode, and if we didn't
do the SBI call, or it didn't succeed call wfi in a loop to at least
save some power.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 arch/riscv/kernel/reset.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/arch/riscv/kernel/reset.c b/arch/riscv/kernel/reset.c
index cfb6eb1d762d..17c810985ad0 100644
--- a/arch/riscv/kernel/reset.c
+++ b/arch/riscv/kernel/reset.c
@@ -8,8 +8,11 @@
 
 static void default_power_off(void)
 {
+#ifndef CONFIG_M_MODE
 	sbi_shutdown();
-	while (1);
+#endif
+	while (1)
+		wait_for_interrupt();
 }
 
 void (*pm_power_off)(void) = default_power_off;
-- 
2.20.1


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