Re: [PATCH 01/14] MIPS: Loongson: Add basic Loongson 3 CPU support.

[David Daney <ddaney.cavm@gmail.com>]

On 06/15/2012 01:09 AM, Huacai Chen wrote:
> Loongson-3 is a multi-core MIPS family CPU, it support MIPS64R2
> fully. Loongson-3 has the same IMP field (0x6300) as Loongson-2.
>
> Loongson-3 has a hardware-maintained cache, system software doesn't
> need to maintain coherency.
>
> Loongson-3A is the first revision of Loongson-3, and it is the quad-
> core version of Loongson-2G. Loongson-3A has a simplified version named
> Loongson-2Gq, the main difference between Loongson-3A/2Gq is 3A has two
> HyperTransport controller but 2Gq has only one. HT0 is used for cross-
> chip interconnection and HT1 is used to link PCI bus. Therefore, 2Gq
> cannot support NUMA but 3A can.
>
> Exsisting Loongson family CPUs:
> Loongson-1: Loongson-1A, Loongson-1B, they are 32-bit MIPS CPUs.
> Loongson-2: Loongson-2E, Loongson-2F, Loongson-2G(including Loongson-
>              2Gq), they are 64-bit MIPS CPUs.
> Loongson-3: Loongson-3A, it is a 64-bit MIPS CPU.
>
> Signed-off-by: Huacai Chen<chenhc@lemote.com>
> Signed-off-by: Hongliang Tao<taohl@lemote.com>
> Signed-off-by: Hua Yan<yanh@lemote.com>
> ---
>   arch/mips/Kconfig                            |   13 ++++
>   arch/mips/include/asm/addrspace.h            |    6 ++
>   arch/mips/include/asm/cpu.h                  |    6 +-
>   arch/mips/include/asm/mach-loongson/spaces.h |   15 +++++
>   arch/mips/include/asm/module.h               |    2 +
>   arch/mips/include/asm/pgtable-bits.h         |    7 ++
>   arch/mips/kernel/Makefile                    |    1 +
>   arch/mips/kernel/cpu-probe.c                 |   12 +++-
>   arch/mips/lib/Makefile                       |    1 +
>   arch/mips/loongson/Kconfig                   |    4 +
>   arch/mips/loongson/Platform                  |    1 +
>   arch/mips/loongson/common/env.c              |    3 +
>   arch/mips/loongson/common/setup.c            |    6 +-
>   arch/mips/mm/Makefile                        |    1 +
>   arch/mips/mm/c-r4k.c                         |   84 ++++++++++++++++++++++++++
>   arch/mips/mm/tlb-r4k.c                       |    2 +-
>   arch/mips/mm/tlbex.c                         |    1 +
>   17 files changed, 156 insertions(+), 9 deletions(-)

This patch is too big.  It should be split up into smaller but related 
parts.

For example, the parts that add new identifier constants should be 
first.  Then a separate patch for cpu-probe.c where they are used.

And...

>   create mode 100644 arch/mips/include/asm/mach-loongson/spaces.h
>
> diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
> index c179461..38e460b 100644
> --- a/arch/mips/Kconfig
> +++ b/arch/mips/Kconfig
> @@ -1544,6 +1544,16 @@ config CPU_LOONGSON2
>   	select CPU_SUPPORTS_64BIT_KERNEL
>   	select CPU_SUPPORTS_HIGHMEM
>
> +config CPU_LOONGSON3
> +	bool "Loongson 3 CPU"
> +	depends on SYS_HAS_CPU_LOONGSON3
> +	select CPU_SUPPORTS_32BIT_KERNEL
> +	select CPU_SUPPORTS_64BIT_KERNEL
> +	select CPU_SUPPORTS_HIGHMEM
> +	help
> +		The Loongson 3 processor implements the MIPS III instruction set
> +		with many extensions.
> +

This bit must be the very last patch of the entire set, not the first.

Ask yourself what would happen if someone did a build selecting 
CPU_LOONGSON3 after this patch were applied?  Would a runnable kernel 
result?  If the answer is no, then you did it in the wrong order.

David Daney