From: Julien Dusser Date: Wed, 19 Jul 2017 12:52:35 +0000 (+0200) Subject: ar71xx: fix lzma loader performance issues X-Git-Url: http://git.openwrt.org/?a=commitdiff_plain;h=8c5702f2a07cebfbee6f9e628b63d88b8806ca1b;hp=06e41056aab12f5fb6c35789d0bde71bcf1dc90e;p=openwrt%2Fstaging%2Fnbd.git 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 --- 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