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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 <markos.chandras@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/7335/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
This commit is contained in:
Markos Chandras 2014-07-14 12:46:13 +01:00 committed by Ralf Baechle
parent 87d08bc94c
commit 3d528b326d
1 changed files with 23 additions and 0 deletions
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23
arch/mips/kernel/cpu-probe.c
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@ -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 = &current_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();