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Commit 78f824d4 authored by Vineet Gupta's avatar Vineet Gupta
Browse files

ARCv2: smp-boot: wake_flag polling by non-Masters needs to be uncached 



This is needed on HS38 cores, for setting up IO-Coherency aperture properly

The polling could perturb the caches and coherecy fabric which could be
wrong in the small window when Master is setting up IOC aperture etc
in arc_cache_init()

We do it only for ARCv2 based builds to not affect EZChip ARCompact
based platform.

Signed-off-by: default avatarVineet Gupta <vgupta@synopsys.com>
parent bf02454a

arch/arc/kernel/smp.c

+16 −3
Original line number Diff line number Diff line
@@ -90,10 +90,23 @@ void __init smp_cpus_done(unsigned int max_cpus) 
 */

static volatile int wake_flag;



#ifdef CONFIG_ISA_ARCOMPACT



#define __boot_read(f)		f

#define __boot_write(f, v)	f = v



#else



#define __boot_read(f)		arc_read_uncached_32(&f)

#define __boot_write(f, v)	arc_write_uncached_32(&f, v)



#endif



static void arc_default_smp_cpu_kick(int cpu, unsigned long pc)

{

	BUG_ON(cpu == 0);

	wake_flag = cpu;



	__boot_write(wake_flag, cpu);

}



void arc_platform_smp_wait_to_boot(int cpu)
@@ -102,10 +115,10 @@ void arc_platform_smp_wait_to_boot(int cpu) 
	if (IS_ENABLED(CONFIG_ARC_SMP_HALT_ON_RESET))

		return;



	while (wake_flag != cpu)

	while (__boot_read(wake_flag) != cpu)

		;



	wake_flag = 0;

	__boot_write(wake_flag, 0);

}



const char *arc_platform_smp_cpuinfo(void)