From 8c5702f2a07cebfbee6f9e628b63d88b8806ca1b Mon Sep 17 00:00:00 2001 From: Julien Dusser Date: Wed, 19 Jul 2017 14:52:35 +0200 Subject: [PATCH] ar71xx: fix lzma loader performance issues Some bootloaders set a cache cohenrency to a very slow mode. Use code from Linux kernel to set it to "Cacheable, noncoherent, write-back, write allocate". Perfomance impact is significant on TP-Link EAP245 board, kernel decompression time fall from 33 seconds to less than 1. Signed-off-by: Julien Dusser --- target/linux/ar71xx/image/lzma-loader/src/head.S | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/target/linux/ar71xx/image/lzma-loader/src/head.S b/target/linux/ar71xx/image/lzma-loader/src/head.S index 47a7c9bd63..d414b14d11 100644 --- a/target/linux/ar71xx/image/lzma-loader/src/head.S +++ b/target/linux/ar71xx/image/lzma-loader/src/head.S @@ -42,6 +42,19 @@ LEAF(startup) mtc0 t0, CP0_STATUS ehb + /* + * Some bootloaders set the 'Kseg0 coherency algorithm' to + * 'Cacheable, noncoherent, write-through, no write allocate' + * and this cause performance issues. Let's go and change it to + * 'Cacheable, noncoherent, write-back, write allocate' + */ + mfc0 t0, CP0_CONFIG + li t1, ~7 #~CONF_CM_CMASK + and t0, t1 + ori t0, 3 #CONF_CM_CACHABLE_NONCOHERENT + mtc0 t0, CP0_CONFIG + nop + mtc0 zero, CP0_COUNT mtc0 zero, CP0_COMPARE ehb -- 2.30.2