cpu: add support for Demeter CPU

This patch adds the basic CPU library code to support the Demeter
CPU.  This CPU is based on the Makalu-ELP core so that CPU lib code
was adapted to create this patch.
Signed-off-by: John Powell <john.powell@arm.com>
Change-Id: Ib5740b748008a72788c557f0654d8d5e9ec0bb7f

include/lib/cpus/aarch64/cortex_demeter.h

+/*
+ * Copyright (c) 2021, Arm Limited. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#ifndef CORTEX_DEMETER_H
+#define CORTEX_DEMETER_H
+
+#define CORTEX_DEMETER_MIDR				U(0x410FD4F0)
+
+/*******************************************************************************
+ * CPU Extended Control register specific definitions
+ ******************************************************************************/
+#define CORTEX_DEMETER_CPUECTLR_EL1			S3_0_C15_C1_4
+
+/*******************************************************************************
+ * CPU Power Control register specific definitions
+ ******************************************************************************/
+#define CORTEX_DEMETER_CPUPWRCTLR_EL1			S3_0_C15_C2_7
+#define CORTEX_DEMETER_CPUPWRCTLR_EL1_CORE_PWRDN_BIT	U(1)
+
+#endif /* CORTEX_DEMETER_H */

lib/cpus/aarch64/cortex_demeter.S

+/*
+ * Copyright (c) 2021, Arm Limited. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <arch.h>
+#include <asm_macros.S>
+#include <common/bl_common.h>
+#include <cortex_demeter.h>
+#include <cpu_macros.S>
+#include <plat_macros.S>
+
+/* Hardware handled coherency */
+#if HW_ASSISTED_COHERENCY == 0
+#error "Cortex Demeter must be compiled with HW_ASSISTED_COHERENCY enabled"
+#endif
+
+/* 64-bit only core */
+#if CTX_INCLUDE_AARCH32_REGS == 1
+#error "Cortex Demeter supports only AArch64. Compile with CTX_INCLUDE_AARCH32_REGS=0"
+#endif
+
+	/* ----------------------------------------------------
+	 * HW will do the cache maintenance while powering down
+	 * ----------------------------------------------------
+	 */
+func cortex_demeter_core_pwr_dwn
+	/* ---------------------------------------------------
+	 * Enable CPU power down bit in power control register
+	 * ---------------------------------------------------
+	 */
+	mrs	x0, CORTEX_DEMETER_CPUPWRCTLR_EL1
+	orr	x0, x0, #CORTEX_DEMETER_CPUPWRCTLR_EL1_CORE_PWRDN_BIT
+	msr	CORTEX_DEMETER_CPUPWRCTLR_EL1, x0
+	isb
+	ret
+endfunc cortex_demeter_core_pwr_dwn
+
+#if REPORT_ERRATA
+/*
+ * Errata printing function for Cortex Demeter. Must follow AAPCS.
+ */
+func cortex_demeter_errata_report
+	ret
+endfunc cortex_demeter_errata_report
+#endif
+
+func cortex_demeter_reset_func
+	/* Disable speculative loads */
+	msr	SSBS, xzr
+	isb
+	ret
+endfunc cortex_demeter_reset_func
+
+	/* ---------------------------------------------
+	 * This function provides Cortex Demeter-
+	 * 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.cortex_demeter_regs, "aS"
+cortex_demeter_regs:  /* The ascii list of register names to be reported */
+	.asciz	"cpuectlr_el1", ""
+
+func cortex_demeter_cpu_reg_dump
+	adr	x6, cortex_demeter_regs
+	mrs	x8, CORTEX_DEMETER_CPUECTLR_EL1
+	ret
+endfunc cortex_demeter_cpu_reg_dump
+
+declare_cpu_ops cortex_demeter, CORTEX_DEMETER_MIDR, \
+	cortex_demeter_reset_func, \
+	cortex_demeter_core_pwr_dwn

plat/arm/board/fvp/platform.mk

@@ -135,6 +135,7 @@ else
 					lib/cpus/aarch64/cortex_a710.S	\
 					lib/cpus/aarch64/cortex_makalu.S	\
 					lib/cpus/aarch64/cortex_makalu_elp_arm.S \
+					lib/cpus/aarch64/cortex_demeter.S	\
 					lib/cpus/aarch64/cortex_a65.S		\
 					lib/cpus/aarch64/cortex_a65ae.S		\
 					lib/cpus/aarch64/cortex_a78c.S