selftests/powerpc: Add matrix multiply assist (MMA) test

Adds a simple test of some basic matrix multiply assist (MMA)
instructions.
Signed-off-by: Alistair Popple <alistair@popple.id.au>
Tested-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200622021832.15870-1-alistair@popple.id.au

tools/testing/selftests/powerpc/include/utils.h

@@ -135,6 +135,11 @@ do {								\
 #define PPC_FEATURE2_ARCH_3_1 0x00040000
 #endif
 
+/* POWER10 features */
+#ifndef PPC_FEATURE2_MMA
+#define PPC_FEATURE2_MMA 0x00020000
+#endif
+
 #if defined(__powerpc64__)
 #define UCONTEXT_NIA(UC)	(UC)->uc_mcontext.gp_regs[PT_NIP]
 #define UCONTEXT_MSR(UC)	(UC)->uc_mcontext.gp_regs[PT_MSR]

tools/testing/selftests/powerpc/math/Makefile

 # SPDX-License-Identifier: GPL-2.0
-TEST_GEN_PROGS := fpu_syscall fpu_preempt fpu_signal fpu_denormal vmx_syscall vmx_preempt vmx_signal vsx_preempt
+TEST_GEN_PROGS := fpu_syscall fpu_preempt fpu_signal fpu_denormal vmx_syscall vmx_preempt vmx_signal vsx_preempt mma
 
 top_srcdir = ../../../../..
 include ../../lib.mk
@@ -17,3 +17,5 @@ $(OUTPUT)/vmx_signal: vmx_asm.S ../utils.c
 
 $(OUTPUT)/vsx_preempt: CFLAGS += -mvsx
 $(OUTPUT)/vsx_preempt: vsx_asm.S ../utils.c
+
+$(OUTPUT)/mma: mma.c mma.S ../utils.c

tools/testing/selftests/powerpc/math/mma.S

+/* SPDX-License-Identifier: GPL-2.0-or-later
+ *
+ * Test basic matrix multiply assist (MMA) functionality if available.
+ *
+ * Copyright 2020, Alistair Popple, IBM Corp.
+ */
+	.global test_mma
+test_mma:
+	/* Load accumulator via VSX registers from image passed in r3 */
+	lxvh8x	4,0,3
+	lxvh8x	5,0,4
+
+	/* Clear and prime the accumulator (xxsetaccz) */
+	.long	0x7c030162
+
+	/* Prime the accumulator with MMA VSX move to accumulator
+	* X-form (xxmtacc) (not needed due to above zeroing) */
+	//.long 0x7c010162
+
+	/* xvi16ger2s */
+	.long	0xec042958
+
+	/* Store result in image passed in r5 */
+	stxvw4x	0,0,5
+	addi	5,5,16
+	stxvw4x	1,0,5
+	addi	5,5,16
+	stxvw4x	2,0,5
+	addi	5,5,16
+	stxvw4x	3,0,5
+	addi	5,5,16
+
+	blr

tools/testing/selftests/powerpc/math/mma.c

+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Test basic matrix multiply assist (MMA) functionality if available.
+ *
+ * Copyright 2020, Alistair Popple, IBM Corp.
+ */
+#include <stdio.h>
+#include <stdint.h>
+
+#include "utils.h"
+
+extern void test_mma(uint16_t (*)[8], uint16_t (*)[8], uint32_t (*)[4*4]);
+
+static int mma(void)
+{
+	int i;
+	int rc = 0;
+	uint16_t x[] = {1, 0, 2, 0, 3, 0, 4, 0};
+	uint16_t y[] = {1, 0, 2, 0, 3, 0, 4, 0};
+	uint32_t z[4*4];
+	uint32_t exp[4*4] = {1, 2, 3, 4,
+			     2, 4, 6, 8,
+			     3, 6, 9, 12,
+			     4, 8, 12, 16};
+
+	SKIP_IF_MSG(!have_hwcap2(PPC_FEATURE2_ARCH_3_1), "Need ISAv3.1");
+	SKIP_IF_MSG(!have_hwcap2(PPC_FEATURE2_MMA), "Need MMA");
+
+	test_mma(&x, &y, &z);
+
+	for (i = 0; i < 16; i++) {
+		printf("MMA[%d] = %d ", i, z[i]);
+
+		if (z[i] == exp[i]) {
+			printf(" (Correct)\n");
+		} else {
+			printf(" (Incorrect)\n");
+			rc = 1;
+		}
+	}
+
+	return rc;
+}
+
+int main(int argc, char *argv[])
+{
+	return test_harness(mma, "mma");
+}