From: Markos Chandras Date: Mon, 14 Jul 2014 11:46:13 +0000 (+0100) Subject: MIPS: kernel: cpu-probe: Add support for the HardWare Table Walker X-Git-Tag: firefly_0821_release~176^2~3460^2~42 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=3d528b326d7da8e28ec62c2ff1a92e85d93af098;p=firefly-linux-kernel-4.4.55.git MIPS: kernel: cpu-probe: Add support for the HardWare Table Walker Detect if the core implements the HTW and set the option accordingly. Also, add a new kernel parameter called 'nohtw' allowing the user to disable the htw support and fallback to the software refill handler. Signed-off-by: Markos Chandras Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/7335/ Signed-off-by: Ralf Baechle --- diff --git a/arch/mips/kernel/cpu-probe.c b/arch/mips/kernel/cpu-probe.c index 2d2e2877b1ea..0d30433db54b 100644 --- a/arch/mips/kernel/cpu-probe.c +++ b/arch/mips/kernel/cpu-probe.c @@ -54,6 +54,20 @@ static int __init dsp_disable(char *s) __setup("nodsp", dsp_disable); +static int mips_htw_disabled; + +static int __init htw_disable(char *s) +{ + mips_htw_disabled = 1; + cpu_data[0].options &= ~MIPS_CPU_HTW; + write_c0_pwctl(read_c0_pwctl() & + ~(1 << MIPS_PWCTL_PWEN_SHIFT)); + + return 1; +} + +__setup("nohtw", htw_disable); + static inline void check_errata(void) { struct cpuinfo_mips *c = ¤t_cpu_data; @@ -321,6 +335,9 @@ static inline unsigned int decode_config3(struct cpuinfo_mips *c) c->options |= MIPS_CPU_SEGMENTS; if (config3 & MIPS_CONF3_MSA) c->ases |= MIPS_ASE_MSA; + /* Only tested on 32-bit cores */ + if ((config3 & MIPS_CONF3_PW) && config_enabled(CONFIG_32BIT)) + c->options |= MIPS_CPU_HTW; return config3 & MIPS_CONF_M; } @@ -1193,6 +1210,12 @@ void cpu_probe(void) if (mips_dsp_disabled) c->ases &= ~(MIPS_ASE_DSP | MIPS_ASE_DSP2P); + if (mips_htw_disabled) { + c->options &= ~MIPS_CPU_HTW; + write_c0_pwctl(read_c0_pwctl() & + ~(1 << MIPS_PWCTL_PWEN_SHIFT)); + } + if (c->options & MIPS_CPU_FPU) { c->fpu_id = cpu_get_fpu_id();