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Commit 3d528b32 authored by Markos Chandras's avatar Markos Chandras Committed by Ralf Baechle
Browse files

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: default avatarMarkos Chandras <markos.chandras@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/7335/


Signed-off-by: default avatarRalf Baechle <ralf@linux-mips.org>
parent 87d08bc9

arch/mips/kernel/cpu-probe.c

+23 −0
Original line number Diff line number Diff line
@@ -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();