arm: cpu: armv8: add L3 memory flush support

Add L3 memory flush support for NS3.

Signed-off-by: Rayagonda Kokatanur <rayagonda.kokatanur@broadcom.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

arch/arm/cpu/armv8/Makefile

@@ -39,3 +39,4 @@ obj-$(CONFIG_S32V234) += s32v234/
 obj-$(CONFIG_TARGET_HIKEY) += hisilicon/
 obj-$(CONFIG_ARMV8_PSCI) += psci.o
 obj-$(CONFIG_ARCH_SUNXI) += lowlevel_init.o
+obj-$(CONFIG_TARGET_BCMNS3) += bcmns3/

arch/arm/cpu/armv8/bcmns3/Makefile

@@ -0,0 +1,5 @@
+# SPDX-License-Identifier: GPL-2.0+
+#
+# Copyright 2020 Broadcom.
+
+obj-y	+= lowlevel.o

arch/arm/cpu/armv8/bcmns3/lowlevel.S

@@ -0,0 +1,89 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Copyright 2020 Broadcom.
+ *
+ */
+
+#include <asm/macro.h>
+#include <linux/linkage.h>
+
+hnf_pstate_poll:
+	/* x0 has the desired status, return 0 for success, 1 for timeout
+	 * clobber x1, x2, x3, x4, x6, x7
+	 */
+	mov	x1, x0
+	mov	x7, #0			/* flag for timeout */
+	mrs	x3, cntpct_el0		/* read timer */
+	mov	w0, #600
+	mov	w6, #1000
+	mul	w0, w0, w6
+	add	x3, x3, x0		/* timeout after 100 microseconds */
+	mov	x0, #0x18
+	movk	x0, #0x6120, lsl #16	/* HNF0_PSTATE_STATUS */
+	mov	w6, #4			/* HN-F node count */
+1:
+	ldr	x2, [x0]
+	cmp	x2, x1			/* check status */
+	b.eq	2f
+	mrs	x4, cntpct_el0
+	cmp	x4, x3
+	b.ls	1b
+	mov	x7, #1			/* timeout */
+	b	3f
+2:
+	add	x0, x0, #0x10000	/* move to next node */
+	subs	w6, w6, #1
+	cbnz	w6, 1b
+3:
+	mov	x0, x7
+	ret
+
+hnf_set_pstate:
+	/* x0 has the desired state, clobber x1, x2, x6 */
+	mov	x1, x0
+	/* power state to SFONLY */
+	mov	w6, #4			/* HN-F node count */
+	mov	x0, #0x10
+	movk x0, #0x6120, lsl #16		/* HNF0_PSTATE_REQ */
+1:	/* set pstate to sfonly */
+	ldr	x2, [x0]
+	and	x2, x2, #0xfffffffffffffffc	/* & HNFPSTAT_MASK */
+	orr	x2, x2, x1
+	str	x2, [x0]
+	add	x0, x0, #0x10000	/* move to next node */
+	subs	w6, w6, #1
+	cbnz	w6, 1b
+
+	ret
+
+ENTRY(__asm_flush_l3_dcache)
+	/*
+	 * Return status in x0
+	 *    success 0
+	 *    timeout 1 for setting SFONLY, 2 for FAM, 3 for both
+	 */
+	mov	x29, lr
+	mov	x8, #0
+
+	dsb	sy
+	mov	x0, #0x1		/* HNFPSTAT_SFONLY */
+	bl	hnf_set_pstate
+
+	mov	x0, #0x4		/* SFONLY status */
+	bl	hnf_pstate_poll
+	cbz	x0, 1f
+	mov	x8, #1			/* timeout */
+1:
+	dsb	sy
+	mov	x0, #0x3		/* HNFPSTAT_FAM */
+	bl	hnf_set_pstate
+
+	mov	x0, #0xc		/* FAM status */
+	bl	hnf_pstate_poll
+	cbz	x0, 1f
+	add	x8, x8, #0x2
+1:
+	mov	x0, x8
+	mov	lr, x29
+	ret
+ENDPROC(__asm_flush_l3_dcache)