diff options
| author | Huacai Chen <chenhc@lemote.com> | 2016-03-03 09:45:13 +0800 |
|---|---|---|
| committer | Ralf Baechle <ralf@linux-mips.org> | 2016-05-13 14:02:15 +0200 |
| commit | 1e820da3c9af4f5771d2ad47099919429b906ac6 (patch) | |
| tree | bb4782e16be098d8b8019bd881224183e724cbaf /arch/mips/mm/c-r4k.c | |
| parent | 380cd582c08831217ae693c86411902e6300ba6b (diff) | |
MIPS: Loongson-3: Introduce CONFIG_LOONGSON3_ENHANCEMENT
New Loongson 3 CPU (since Loongson-3A R2, as opposed to Loongson-3A R1,
Loongson-3B R1 and Loongson-3B R2) has many enhancements, such as FTLB,
L1-VCache, EI/DI/Wait/Prefetch instruction, DSP/DSPv2 ASE, User Local
register, Read-Inhibit/Execute-Inhibit, SFB (Store Fill Buffer), Fast
TLB refill support, etc.
This patch introduce a config option, CONFIG_LOONGSON3_ENHANCEMENT, to
enable those enhancements which are not probed at run time. If you want
a generic kernel to run on all Loongson 3 machines, please say 'N'
here. If you want a high-performance kernel to run on new Loongson 3
machines only, please say 'Y' here.
Some additional explanations:
1) SFB locates between core and L1 cache, it causes memory access out
of order, so writel/outl (and other similar functions) need a I/O
reorder barrier.
2) Loongson 3 has a bug that di instruction can not save the irqflag,
so arch_local_irq_save() is modified. Since CPU_MIPSR2 is selected
by CONFIG_LOONGSON3_ENHANCEMENT, generic kernel doesn't use ei/di
at all.
3) CPU_HAS_PREFETCH is selected by CONFIG_LOONGSON3_ENHANCEMENT, so
MIPS_CPU_PREFETCH (used by uasm) probing is also put in this patch.
Signed-off-by: Huacai Chen <chenhc@lemote.com>
Cc: Aurelien Jarno <aurelien@aurel32.net>
Cc: Steven J . Hill <sjhill@realitydiluted.com>
Cc: Fuxin Zhang <zhangfx@lemote.com>
Cc: Zhangjin Wu <wuzhangjin@gmail.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/12755/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Diffstat (limited to 'arch/mips/mm/c-r4k.c')
| -rw-r--r-- | arch/mips/mm/c-r4k.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/mips/mm/c-r4k.c b/arch/mips/mm/c-r4k.c index 3415d3e2a63b..d73b304cfe8a 100644 --- a/arch/mips/mm/c-r4k.c +++ b/arch/mips/mm/c-r4k.c @@ -1161,6 +1161,8 @@ static void probe_pcache(void) c->dcache.ways * c->dcache.linesz; c->dcache.waybit = 0; + if ((prid & PRID_REV_MASK) >= PRID_REV_LOONGSON3A_R2) + c->options |= MIPS_CPU_PREFETCH; break; case CPU_CAVIUM_OCTEON3: |