Loongson doesn't support DMA address above 4GB traditionally. If memory
is more than 4GB, CONFIG_SWIOTLB and ZONE_DMA32 should be selected. In
this way, DMA pages are allocated below 4GB preferably. However, if low
memory is not enough, high pages are allocated and swiotlb is used for
bouncing.
Moreover, we provide a platform-specific dma_map_ops::set_dma_mask() to
set a device's dma_mask and coherent_dma_mask. We use these masks to
distinguishes an allocated page can be used for DMA directly, or need
swiotlb to bounce.
Recently, we found that 32-bit DMA isn't a hardware bug, but a hardware
configuration issue. So, latest firmware has enable the DMA support as
high as 40-bit. To support all-memory DMA for all devices (besides the
Loongson platform limit, there are still some devices have their own
DMA32 limit), and also to be compatible with old firmware, we keep use
swiotlb.
Signed-off-by: Huacai Chen <chenhc@lemote.com>
Signed-off-by: Hongliang Tao <taohl@lemote.com>
Signed-off-by: Hua Yan <yanh@lemote.com>
Tested-by: Alex Smith <alex.smith@imgtec.com>
Reviewed-by: Alex Smith <alex.smith@imgtec.com>
Cc: John Crispin <john@phrozen.org>
Cc: Steven J. Hill <Steven.Hill@imgtec.com>
Cc: Aurelien Jarno <aurelien@aurel32.net>
Cc: linux-mips@linux-mips.org
Cc: Fuxin Zhang <zhangfx@lemote.com>
Cc: Zhangjin Wu <wuzhangjin@gmail.com>
Patchwork: https://patchwork.linux-mips.org/patch/6636
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Loongson 2F has built-in DDR2 and PCI-X controller. The PCI-X controller
has a programming interface similiar to the the FPGA northbridge used on
Loongson 2E.
The main differences between Loongson 2E and Loongson 2F include:
1. Loongson 2F has an extra address window configuration module, which
is used to map CPU address space to DDR or PCI address space, or map
the PCI-DMA address space to DDR or LIO address space.
2. Loongson 2F supports 8 levels of software configurable CPu frequency
which can be configured in the LOONGSON_CHIPCFG0 register. The coming
cpufreq and standby support are based on this feature.
Loongson.h abstracts the modules and corresponding methods are abstracted.
Add other Loongson-2F-specific source code including gcc 4.4 support, PCI
memory space, PCI IO space, DMA address.
Signed-off-by: Wu Zhangjin <wuzhangjin@gmail.com>
Cc: linux-mips@linux-mips.org
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
To make source code of loongson sharable to the machines(such as gdium)
made by the other companies, we rename arch/mips/lemote to
arch/mips/loongson, asm/mach-lemote to asm/mach-loongson, and rename lm2e
to the name of the machine: fuloong-2e. accordingly, FULONG are renamed to
FULOONG2E to make it distinguishable to the future FULOONG2F. and also,
some other relative tuning is needed.
Signed-off-by: Wu Zhangjin <wuzhangjin@gmail.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
