neoverse_n2.S

/*
 * Copyright (c) 2020, Arm Limited. All rights reserved.
 *
 * SPDX-License-Identifier: BSD-3-Clause
 */

#include <arch.h>
#include <asm_macros.S>
#include <cpu_macros.S>
#include <neoverse_n2.h>

/* Hardware handled coherency */
#if HW_ASSISTED_COHERENCY == 0
#error "Neoverse N2 must be compiled with HW_ASSISTED_COHERENCY enabled"
#endif

/* 64-bit only core */
#if CTX_INCLUDE_AARCH32_REGS == 1
#error "Neoverse-N2 supports only AArch64. Compile with CTX_INCLUDE_AARCH32_REGS=0"
#endif

/* --------------------------------------------------
 * Errata Workaround for Neoverse N2 Erratum 2002655.
 * This applies to revision r0p0 of Neoverse N2. it is still open.
 * Inputs:
 * x0: variant[4:7] and revision[0:3] of current cpu.
 * Shall clobber: x0-x17
 * --------------------------------------------------
 */
func errata_n2_2002655_wa
	/* Check revision. */
	mov	x17, x30
	bl	check_errata_2002655
	cbz	x0, 1f

	/* Apply instruction patching sequence */
	ldr x0,=0x6
	msr S3_6_c15_c8_0,x0
	ldr x0,=0xF3A08002
	msr S3_6_c15_c8_2,x0
	ldr x0,=0xFFF0F7FE
	msr S3_6_c15_c8_3,x0
	ldr x0,=0x40000001003ff
	msr S3_6_c15_c8_1,x0
	ldr x0,=0x7
	msr S3_6_c15_c8_0,x0
	ldr x0,=0xBF200000
	msr S3_6_c15_c8_2,x0
	ldr x0,=0xFFEF0000
	msr S3_6_c15_c8_3,x0
	ldr x0,=0x40000001003f3
	msr S3_6_c15_c8_1,x0
	isb
1:
	ret	x17
endfunc errata_n2_2002655_wa

func check_errata_2002655
	/* Applies to r0p0 */
	mov	x1, #0x00
	b	cpu_rev_var_ls
endfunc check_errata_2002655

	/* -------------------------------------------------
	 * The CPU Ops reset function for Neoverse N2.
	 * -------------------------------------------------
	 */
func neoverse_n2_reset_func
	mov	x19, x30

	/* Check if the PE implements SSBS */
	mrs	x0, id_aa64pfr1_el1
	tst	x0, #(ID_AA64PFR1_EL1_SSBS_MASK << ID_AA64PFR1_EL1_SSBS_SHIFT)
	b.eq	1f

	/* Disable speculative loads */
	msr	SSBS, xzr
1:
	/* Force all cacheable atomic instructions to be near */
	mrs	x0, NEOVERSE_N2_CPUACTLR2_EL1
	orr	x0, x0, #NEOVERSE_N2_CPUACTLR2_EL1_BIT_2
	msr	NEOVERSE_N2_CPUACTLR2_EL1, x0

#if ENABLE_AMU
	/* Make sure accesses from EL0/EL1 and EL2 are not trapped to EL3 */
	mrs	x0, cptr_el3
	orr	x0, x0, #TAM_BIT
	msr	cptr_el3, x0

	/* Make sure accesses from EL0/EL1 are not trapped to EL2 */
	mrs	x0, cptr_el2
	orr	x0, x0, #TAM_BIT
	msr	cptr_el2, x0

	/* No need to enable the counters as this would be done at el3 exit */
#endif

#if NEOVERSE_Nx_EXTERNAL_LLC
	/* Some systems may have External LLC, core needs to be made aware */
	mrs     x0, NEOVERSE_N2_CPUECTLR_EL1
	orr     x0, x0, NEOVERSE_N2_CPUECTLR_EL1_EXTLLC_BIT
	msr     NEOVERSE_N2_CPUECTLR_EL1, x0
#endif

	bl	cpu_get_rev_var
	mov	x18, x0

#if ERRATA_N2_2002655
	mov	x0, x18
	bl	errata_n2_2002655_wa
#endif

	isb
	ret x19
endfunc neoverse_n2_reset_func

func neoverse_n2_core_pwr_dwn
	/* ---------------------------------------------
	 * Enable CPU power down bit in power control register
	 * No need to do cache maintenance here.
	 * ---------------------------------------------
	 */
	mrs	x0, NEOVERSE_N2_CPUPWRCTLR_EL1
	orr	x0, x0, #NEOVERSE_N2_CORE_PWRDN_EN_BIT
	msr	NEOVERSE_N2_CPUPWRCTLR_EL1, x0
	isb
	ret
endfunc neoverse_n2_core_pwr_dwn

#if REPORT_ERRATA
/*
 * Errata printing function for Neoverse N2 cores. Must follow AAPCS.
 */
func neoverse_n2_errata_report
	stp	x8, x30, [sp, #-16]!

	bl	cpu_get_rev_var
	mov	x8, x0

	/*
	 * Report all errata. The revision-variant information is passed to
	 * checking functions of each errata.
	 */
	report_errata ERRATA_N2_2002655, neoverse_n2, 2002655

	ldp	x8, x30, [sp], #16
	ret
endfunc neoverse_n2_errata_report
#endif

	/* ---------------------------------------------
	 * This function provides Neoverse N2 specific
	 * register information for crash reporting.
	 * It needs to return with x6 pointing to
	 * a list of register names in ASCII and
	 * x8 - x15 having values of registers to be
	 * reported.
	 * ---------------------------------------------
	 */
.section .rodata.neoverse_n2_regs, "aS"
neoverse_n2_regs:  /* The ASCII list of register names to be reported */
	.asciz	"cpupwrctlr_el1", ""

func neoverse_n2_cpu_reg_dump
	adr	x6, neoverse_n2_regs
	mrs	x8, NEOVERSE_N2_CPUPWRCTLR_EL1
	ret
endfunc neoverse_n2_cpu_reg_dump

declare_cpu_ops neoverse_n2, NEOVERSE_N2_MIDR, \
	neoverse_n2_reset_func, \
	neoverse_n2_core_pwr_dwn