ARC: [plat-eznps] use schd.wft instruction instead of sleep at idle task (644fa02b) · Commits · 戴 / test

When HW threads are active we want CPU to enter idle state only for the calling HW thread and not to put on sleep all HW threads sharing this core. For this need the NPS400 got dedicated instruction so only calling thread is entring sleep and all other are still awake and can execute instructions. Signed-off-by:

Noam Camus <noamca@mellanox.com> Signed-off-by:

Vineet Gupta <vgupta@synopsys.com> [vgupta: reworked patch to not use inline ifdef but a new function itself]

arch/arc/kernel/process.c

+12 −1

Original line number	Diff line number	Diff line
		@@ -92,7 +92,18 @@ void arch_cpu_idle(void)
		:"I"(arg)); /* can't be "r" has to be embedded const */
		}

		#else
		#elif defined(CONFIG_EZNPS_MTM_EXT) /* ARC700 variant in NPS */

		void arch_cpu_idle(void)
		{
		/* only the calling HW thread needs to sleep */
		__asm__ __volatile__(
		".word %0 \n"
		:
		:"i"(CTOP_INST_HWSCHD_WFT_IE12));
		}

		#else /* ARC700 */

		void arch_cpu_idle(void)
		{

arch/arc/plat-eznps/include/plat/ctop.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -46,6 +46,7 @@
		#define CTOP_AUX_UDMC (CTOP_AUX_BASE + 0x300)

		/* EZchip core instructions */
		#define CTOP_INST_HWSCHD_WFT_IE12 0x3E6F7344
		#define CTOP_INST_HWSCHD_OFF_R4 0x3C6F00BF
		#define CTOP_INST_HWSCHD_RESTORE_R4 0x3E6F7103
		#define CTOP_INST_SCHD_RW 0x3E6F7004

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