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Commit 6b3edefe authored by Nicholas Piggin's avatar Nicholas Piggin Committed by Michael Ellerman
Browse files

powerpc/powernv: POWER9 support for msgsnd/doorbell IPI 



POWER9 requires msgsync for receiver-side synchronization, and a DD1
workaround restricts IPIs to core-local.

Signed-off-by: default avatarNicholas Piggin <npiggin@gmail.com>
[mpe: Drop no longer needed asm feature macro changes]
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
parent a5adf282

arch/powerpc/include/asm/dbell.h

+3 −0
Original line number Diff line number Diff line
@@ -51,6 +51,9 @@ static inline void ppc_msgsnd_sync(void) 
/* sync after taking message interrupt */

static inline void ppc_msgsync(void)

{

	/* sync is not required when taking messages from the same core */

	__asm__ __volatile__ (ASM_FTR_IFSET(PPC_MSGSYNC " ; lwsync", "", %0)

				: : "i" (CPU_FTR_HVMODE|CPU_FTR_ARCH_300));

}



#else /* CONFIG_PPC_BOOK3S */

arch/powerpc/include/asm/ppc-opcode.h

+2 −0
Original line number Diff line number Diff line
@@ -161,6 +161,7 @@ 
#define PPC_INST_MFTMR			0x7c0002dc

#define PPC_INST_MSGSND			0x7c00019c

#define PPC_INST_MSGCLR			0x7c0001dc

#define PPC_INST_MSGSYNC		0x7c0006ec

#define PPC_INST_MSGSNDP		0x7c00011c

#define PPC_INST_MTTMR			0x7c0003dc

#define PPC_INST_NOP			0x60000000
@@ -345,6 +346,7 @@ 
					___PPC_RB(b) | __PPC_EH(eh))

#define PPC_MSGSND(b)		stringify_in_c(.long PPC_INST_MSGSND | \

					___PPC_RB(b))

#define PPC_MSGSYNC		stringify_in_c(.long PPC_INST_MSGSYNC)

#define PPC_MSGCLR(b)		stringify_in_c(.long PPC_INST_MSGCLR | \

					___PPC_RB(b))

#define PPC_MSGSNDP(b)		stringify_in_c(.long PPC_INST_MSGSNDP | \

arch/powerpc/platforms/powernv/smp.c

+26 −2
Original line number Diff line number Diff line
@@ -257,6 +257,23 @@ static void pnv_cause_ipi(int cpu) 
	icp_ops->cause_ipi(cpu);

}



static void pnv_p9_dd1_cause_ipi(int cpu)

{

	int this_cpu = get_cpu();



	/*

	 * POWER9 DD1 has a global addressed msgsnd, but for now we restrict

	 * IPIs to same core, because it requires additional synchronization

	 * for inter-core doorbells which we do not implement.

	 */

	if (cpumask_test_cpu(cpu, cpu_sibling_mask(this_cpu)))

		doorbell_global_ipi(cpu);

	else

		icp_ops->cause_ipi(cpu);



	put_cpu();

}



static void __init pnv_smp_probe(void)

{

	if (xive_enabled())
@@ -264,8 +281,15 @@ static void __init pnv_smp_probe(void) 
	else

		xics_smp_probe();



	if (cpu_has_feature(CPU_FTR_DBELL) && !cpu_has_feature(CPU_FTR_ARCH_300)) {

	if (cpu_has_feature(CPU_FTR_DBELL)) {

		if (cpu_has_feature(CPU_FTR_ARCH_300)) {

			if (cpu_has_feature(CPU_FTR_POWER9_DD1))

				smp_ops->cause_ipi = pnv_p9_dd1_cause_ipi;

			else

				smp_ops->cause_ipi = doorbell_global_ipi;

		} else {

			smp_ops->cause_ipi = pnv_cause_ipi;

		}

	} else {

		smp_ops->cause_ipi = icp_ops->cause_ipi;

	}