| Message ID | 20200521140725.29571-7-Sergey.Semin@baikalelectronics.ru (mailing list archive) |
|---|---|
| State | Accepted |
| Headers | show |
| Series | mips: Prepare MIPS-arch code for Baikal-T1 SoC support | expand |
On Thu, May 21, 2020 at 05:07:17PM +0300, Serge Semin wrote: > CP0 config register may indicate whether write-through merging > is allowed. Currently there are two types of the merging available: > SysAD Valid and Full modes. Whether each of them are supported by > the core is implementation dependent. Moreover whether the ability > to change the mode also depends on the chip family instance. Taking > into account all of this we created a dedicated mm_config() method > to detect and enable merging if it's supported. It is called for > MIPS-type processors at CPU-probe stage and attempts to detect whether > the write merging is available. If it's known to be supported and > switchable, then switch on the full mode. Otherwise just perform the > CP0.Config.MM field analysis. > > In addition there are platforms like InterAptiv/ProAptiv, which do have > the MM bit field set by default, but having write-through cacheing > unsupported makes write-merging also unsupported. In this case we just > ignore the MM field value. > > Co-developed-by: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru> > Signed-off-by: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru> > Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru> > Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> > Cc: Paul Burton <paulburton@kernel.org> > Cc: Ralf Baechle <ralf@linux-mips.org> > Cc: Arnd Bergmann <arnd@arndb.de> > Cc: Rob Herring <robh+dt@kernel.org> > Cc: devicetree@vger.kernel.org > --- > arch/mips/include/asm/cpu-features.h | 8 +++++ > arch/mips/include/asm/cpu.h | 4 ++- > arch/mips/include/asm/mipsregs.h | 3 ++ > arch/mips/kernel/cpu-probe.c | 48 ++++++++++++++++++++++++++++ > 4 files changed, 62 insertions(+), 1 deletion(-) applied to mips-next. Thomas.
diff --git a/arch/mips/include/asm/cpu-features.h b/arch/mips/include/asm/cpu-features.h index 14532cd25807..caecbae4b599 100644 --- a/arch/mips/include/asm/cpu-features.h +++ b/arch/mips/include/asm/cpu-features.h @@ -629,6 +629,14 @@ # endif #endif +#ifndef cpu_has_mm_sysad +# define cpu_has_mm_sysad __opt(MIPS_CPU_MM_SYSAD) +#endif + +#ifndef cpu_has_mm_full +# define cpu_has_mm_full __opt(MIPS_CPU_MM_FULL) +#endif + /* * Guest capabilities */ diff --git a/arch/mips/include/asm/cpu.h b/arch/mips/include/asm/cpu.h index 4b84fd1df0c7..104a509312b3 100644 --- a/arch/mips/include/asm/cpu.h +++ b/arch/mips/include/asm/cpu.h @@ -422,7 +422,9 @@ enum cpu_type_enum { #define MIPS_CPU_MT_PER_TC_PERF_COUNTERS \ BIT_ULL(56) /* CPU has perf counters implemented per TC (MIPSMT ASE) */ #define MIPS_CPU_MMID BIT_ULL(57) /* CPU supports MemoryMapIDs */ -#define MIPS_CPU_MAC_2008_ONLY BIT_ULL(58) /* CPU Only support MAC2008 Fused multiply-add instruction */ +#define MIPS_CPU_MM_SYSAD BIT_ULL(58) /* CPU supports write-through SysAD Valid merge */ +#define MIPS_CPU_MM_FULL BIT_ULL(59) /* CPU supports write-through full merge */ +#define MIPS_CPU_MAC_2008_ONLY BIT_ULL(60) /* CPU Only support MAC2008 Fused multiply-add instruction */ /* * CPU ASE encodings diff --git a/arch/mips/include/asm/mipsregs.h b/arch/mips/include/asm/mipsregs.h index 246b8b2ebdf8..a284da54efd5 100644 --- a/arch/mips/include/asm/mipsregs.h +++ b/arch/mips/include/asm/mipsregs.h @@ -563,6 +563,9 @@ #define MIPS_CONF_MT_FTLB (_ULCAST_(4) << 7) #define MIPS_CONF_AR (_ULCAST_(7) << 10) #define MIPS_CONF_AT (_ULCAST_(3) << 13) +#define MIPS_CONF_MM (_ULCAST_(3) << 17) +#define MIPS_CONF_MM_SYSAD (_ULCAST_(1) << 17) +#define MIPS_CONF_MM_FULL (_ULCAST_(2) << 17) #define MIPS_CONF_M (_ULCAST_(1) << 31) /* diff --git a/arch/mips/kernel/cpu-probe.c b/arch/mips/kernel/cpu-probe.c index 33600287daf7..04366f58ce4a 100644 --- a/arch/mips/kernel/cpu-probe.c +++ b/arch/mips/kernel/cpu-probe.c @@ -672,6 +672,52 @@ static int set_ftlb_enable(struct cpuinfo_mips *c, enum ftlb_flags flags) return 0; } +static int mm_config(struct cpuinfo_mips *c) +{ + unsigned int config0, update, mm; + + config0 = read_c0_config(); + mm = config0 & MIPS_CONF_MM; + + /* + * It's implementation dependent what type of write-merge is supported + * and whether it can be enabled/disabled. If it is settable lets make + * the merging allowed by default. Some platforms might have + * write-through caching unsupported. In this case just ignore the + * CP0.Config.MM bit field value. + */ + switch (c->cputype) { + case CPU_24K: + case CPU_34K: + case CPU_74K: + case CPU_P5600: + case CPU_P6600: + c->options |= MIPS_CPU_MM_FULL; + update = MIPS_CONF_MM_FULL; + break; + case CPU_1004K: + case CPU_1074K: + case CPU_INTERAPTIV: + case CPU_PROAPTIV: + mm = 0; + fallthrough; + default: + update = 0; + break; + } + + if (update) { + config0 = (config0 & ~MIPS_CONF_MM) | update; + write_c0_config(config0); + } else if (mm == MIPS_CONF_MM_SYSAD) { + c->options |= MIPS_CPU_MM_SYSAD; + } else if (mm == MIPS_CONF_MM_FULL) { + c->options |= MIPS_CPU_MM_FULL; + } + + return 0; +} + static inline unsigned int decode_config0(struct cpuinfo_mips *c) { unsigned int config0; @@ -1763,6 +1809,8 @@ static inline void cpu_probe_mips(struct cpuinfo_mips *c, unsigned int cpu) spram_config(); + mm_config(c); + switch (__get_cpu_type(c->cputype)) { case CPU_M5150: case CPU_P5600: