Commit 1e820da3 authored by Huacai Chen's avatar Huacai Chen Committed by Ralf Baechle
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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: default avatarHuacai 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: default avatarRalf Baechle <ralf@linux-mips.org>
parent 380cd582
......@@ -1360,6 +1360,24 @@ config CPU_LOONGSON3
The Loongson 3 processor implements the MIPS64R2 instruction
set with many extensions.
config LOONGSON3_ENHANCEMENT
bool "New Loongson 3 CPU Enhancements"
default n
select CPU_MIPSR2
select CPU_HAS_PREFETCH
depends on CPU_LOONGSON3
help
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 option 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.
config CPU_LOONGSON2E
bool "Loongson 2E"
depends on SYS_HAS_CPU_LOONGSON2E
......
......@@ -22,7 +22,8 @@
/*
* TLB hazards
*/
#if defined(CONFIG_CPU_MIPSR2) || defined(CONFIG_CPU_MIPSR6) && !defined(CONFIG_CPU_CAVIUM_OCTEON)
#if (defined(CONFIG_CPU_MIPSR2) || defined(CONFIG_CPU_MIPSR6)) && \
!defined(CONFIG_CPU_CAVIUM_OCTEON) && !defined(CONFIG_LOONGSON3_ENHANCEMENT)
/*
* MIPSR2 defines ehb for hazard avoidance
......@@ -155,8 +156,8 @@ do { \
} while (0)
#elif defined(CONFIG_MIPS_ALCHEMY) || defined(CONFIG_CPU_CAVIUM_OCTEON) || \
defined(CONFIG_CPU_LOONGSON2) || defined(CONFIG_CPU_R10000) || \
defined(CONFIG_CPU_R5500) || defined(CONFIG_CPU_XLR)
defined(CONFIG_CPU_LOONGSON2) || defined(CONFIG_LOONGSON3_ENHANCEMENT) || \
defined(CONFIG_CPU_R10000) || defined(CONFIG_CPU_R5500) || defined(CONFIG_CPU_XLR)
/*
* R10000 rocks - all hazards handled in hardware, so this becomes a nobrainer.
......
......@@ -304,10 +304,10 @@ static inline void iounmap(const volatile void __iomem *addr)
#undef __IS_KSEG1
}
#ifdef CONFIG_CPU_CAVIUM_OCTEON
#define war_octeon_io_reorder_wmb() wmb()
#if defined(CONFIG_CPU_CAVIUM_OCTEON) || defined(CONFIG_LOONGSON3_ENHANCEMENT)
#define war_io_reorder_wmb() wmb()
#else
#define war_octeon_io_reorder_wmb() do { } while (0)
#define war_io_reorder_wmb() do { } while (0)
#endif
#define __BUILD_MEMORY_SINGLE(pfx, bwlq, type, irq) \
......@@ -318,7 +318,7 @@ static inline void pfx##write##bwlq(type val, \
volatile type *__mem; \
type __val; \
\
war_octeon_io_reorder_wmb(); \
war_io_reorder_wmb(); \
\
__mem = (void *)__swizzle_addr_##bwlq((unsigned long)(mem)); \
\
......@@ -387,7 +387,7 @@ static inline void pfx##out##bwlq##p(type val, unsigned long port) \
volatile type *__addr; \
type __val; \
\
war_octeon_io_reorder_wmb(); \
war_io_reorder_wmb(); \
\
__addr = (void *)__swizzle_addr_##bwlq(mips_io_port_base + port); \
\
......
......@@ -41,7 +41,12 @@ static inline unsigned long arch_local_irq_save(void)
" .set push \n"
" .set reorder \n"
" .set noat \n"
#if defined(CONFIG_CPU_LOONGSON3)
" mfc0 %[flags], $12 \n"
" di \n"
#else
" di %[flags] \n"
#endif
" andi %[flags], 1 \n"
" " __stringify(__irq_disable_hazard) " \n"
" .set pop \n"
......
......@@ -26,6 +26,12 @@
mfc0 t0, $5, 1
or t0, (0x1 << 29)
mtc0 t0, $5, 1
#ifdef CONFIG_LOONGSON3_ENHANCEMENT
/* Enable STFill Buffer */
mfc0 t0, $16, 6
or t0, 0x100
mtc0 t0, $16, 6
#endif
_ehb
.set pop
#endif
......@@ -46,6 +52,12 @@
mfc0 t0, $5, 1
or t0, (0x1 << 29)
mtc0 t0, $5, 1
#ifdef CONFIG_LOONGSON3_ENHANCEMENT
/* Enable STFill Buffer */
mfc0 t0, $16, 6
or t0, 0x100
mtc0 t0, $16, 6
#endif
_ehb
.set pop
#endif
......
......@@ -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:
......
......@@ -188,6 +188,15 @@ static void set_prefetch_parameters(void)
}
break;
case CPU_LOONGSON3:
/* Loongson-3 only support the Pref_Load/Pref_Store. */
pref_bias_clear_store = 128;
pref_bias_copy_load = 128;
pref_bias_copy_store = 128;
pref_src_mode = Pref_Load;
pref_dst_mode = Pref_Store;
break;
default:
pref_bias_clear_store = 128;
pref_bias_copy_load = 256;
......
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