Recent Xorg depends on this hack/patch.
For example,if we are using this memory layout:
0-256MB phys mem
256-512M pci io/mem region
512-768MB phys mem
Xorg will crash due to pci video memory mapping problem.
So this is not really only for Fulong.
BTW:
Songmao, we'd better add a comment to justify this code.
tiansm@xxxxxxxxxx 写道:
> From: Songmao Tian <tiansm@xxxxxxxxxx>
>
> Signed-off-by: Songmao Tian <tiansm@xxxxxxxxxx>
> ---
> arch/mips/lemote/lm2e/Makefile | 2 +-
> arch/mips/lemote/lm2e/mem.c | 25 +++++++++++++++++++++++++
> 2 files changed, 26 insertions(+), 1 deletions(-)
> create mode 100644 arch/mips/lemote/lm2e/mem.c
>
> diff --git a/arch/mips/lemote/lm2e/Makefile b/arch/mips/lemote/lm2e/Makefile
> index 0ba6f12..fb1b48c 100644
> --- a/arch/mips/lemote/lm2e/Makefile
> +++ b/arch/mips/lemote/lm2e/Makefile
> @@ -2,6 +2,6 @@
> # Makefile for Lemote Fulong mini-PC board.
> #
>
> -obj-y += setup.o prom.o reset.o irq.o pci.o bonito-irq.o dbg_io.o
> +obj-y += setup.o prom.o reset.o irq.o pci.o bonito-irq.o dbg_io.o mem.o
> EXTRA_AFLAGS := $(CFLAGS)
>
> diff --git a/arch/mips/lemote/lm2e/mem.c b/arch/mips/lemote/lm2e/mem.c
> new file mode 100644
> index 0000000..6068a17
> --- /dev/null
> +++ b/arch/mips/lemote/lm2e/mem.c
> @@ -0,0 +1,25 @@
> +/*
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms of the GNU General Public License as published by the
> + * Free Software Foundation; either version 2 of the License, or (at your
> + * option) any later version.
> + */
> +
> +#include <linux/fs.h>
> +#include <linux/fcntl.h>
> +#include <linux/mm.h>
> +
> +/* override of arch/mips/mm/cache.c: __uncached_access */
> +int __uncached_access(struct file *file, unsigned long addr)
> +{
> + if (file->f_flags & O_SYNC)
> + return 1;
> +
> + /*
> + * on lemote loongson 2e system, peripheral register
> + * reside between 0x1000 0000 and 0x2000 0000
> + */
> + return addr >= __pa(high_memory) ||
> + ((addr >=0x10000000) && (addr < 0x20000000));
> +}
> +
>
--
------------------------------------------------
张福新
江苏中科龙梦科技有限公司
地址：江苏省常熟市虞山镇梦兰工业园
General Manager
JiangSu Lemote Corp. Ltd.
MengLan, Yushan, Changshu, JiangSu Province, China
ZIP: 215500
Tel: 86-512-52308679
Fax: 86-512-52308688
Email: zhangfx@xxxxxxxxxx
http://www.lemote.com
------------------------------------------------
