cpu_helpers.S

/*
 * Copyright (c) 2014, ARM Limited and Contributors. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * Redistributions of source code must retain the above copyright notice, this
 * list of conditions and the following disclaimer.
 *
 * Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 *
 * Neither the name of ARM nor the names of its contributors may be used
 * to endorse or promote products derived from this software without specific
 * prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include <arch.h>
#include <asm_macros.S>
#include <assert_macros.S>
#include <cpu_macros.S>
#if IMAGE_BL31
#include <cpu_data.h>
#endif

 /* Reset fn is needed in BL at reset vector */
#if IMAGE_BL1 || IMAGE_BL31
	/*
	 * The reset handler common to all platforms.  After a matching
	 * cpu_ops structure entry is found, the correponding reset_handler
	 * in the cpu_ops is invoked.
	 * Clobbers: x0 - x19, x30
	 */
	.globl	reset_handler
func reset_handler
	mov	x19, x30

	/* The plat_reset_handler can clobber x0 - x18, x30 */
	bl	plat_reset_handler

	/* Get the matching cpu_ops pointer */
	bl	get_cpu_ops_ptr
#if ASM_ASSERTION
	cmp	x0, #0
	ASM_ASSERT(ne)
#endif

	/* Get the cpu_ops reset handler */
	ldr	x2, [x0, #CPU_RESET_FUNC]
	mov	x30, x19
	cbz	x2, 1f

	/* The cpu_ops reset handler can clobber x0 - x19, x30 */
	br	x2
1:
	ret
endfunc reset_handler

#endif /* IMAGE_BL1 || IMAGE_BL31 */

#if IMAGE_BL31 /* The power down core and cluster is needed only in  BL31 */
	/*
	 * The prepare core power down function for all platforms.  After
	 * the cpu_ops pointer is retrieved from cpu_data, the corresponding
	 * pwr_dwn_core in the cpu_ops is invoked.
	 */
	.globl	prepare_core_pwr_dwn
func prepare_core_pwr_dwn
	mrs	x1, tpidr_el3
	ldr	x0, [x1, #CPU_DATA_CPU_OPS_PTR]
#if ASM_ASSERTION
	cmp	x0, #0
	ASM_ASSERT(ne)
#endif

	/* Get the cpu_ops core_pwr_dwn handler */
	ldr	x1, [x0, #CPU_PWR_DWN_CORE]
	br	x1
endfunc prepare_core_pwr_dwn

	/*
	 * The prepare cluster power down function for all platforms.  After
	 * the cpu_ops pointer is retrieved from cpu_data, the corresponding
	 * pwr_dwn_cluster in the cpu_ops is invoked.
	 */
	.globl	prepare_cluster_pwr_dwn
func prepare_cluster_pwr_dwn
	mrs	x1, tpidr_el3
	ldr	x0, [x1, #CPU_DATA_CPU_OPS_PTR]
#if ASM_ASSERTION
	cmp	x0, #0
	ASM_ASSERT(ne)
#endif

	/* Get the cpu_ops cluster_pwr_dwn handler */
	ldr	x1, [x0, #CPU_PWR_DWN_CLUSTER]
	br	x1
endfunc prepare_cluster_pwr_dwn


	/*
	 * Initializes the cpu_ops_ptr if not already initialized
	 * in cpu_data. This can be called without a runtime stack, but may
	 * only be called after the MMU is enabled.
	 * clobbers: x0 - x6, x10
	 */
	.globl	init_cpu_ops
func init_cpu_ops
	mrs	x6, tpidr_el3
	ldr	x0, [x6, #CPU_DATA_CPU_OPS_PTR]
	cbnz	x0, 1f
	mov	x10, x30
	bl	get_cpu_ops_ptr
#if ASM_ASSERTION
	cmp	x0, #0
	ASM_ASSERT(ne)
#endif
	str	x0, [x6, #CPU_DATA_CPU_OPS_PTR]!
	mov x30, x10
1:
	ret
endfunc init_cpu_ops
#endif /* IMAGE_BL31 */

#if IMAGE_BL31 && CRASH_REPORTING
	/*
	 * The cpu specific registers which need to be reported in a crash
	 * are reported via cpu_ops cpu_reg_dump function. After a matching
	 * cpu_ops structure entry is found, the correponding cpu_reg_dump
	 * in the cpu_ops is invoked.
	 */
	.globl	do_cpu_reg_dump
func do_cpu_reg_dump
	mov	x16, x30

	/* Get the matching cpu_ops pointer */
	bl	get_cpu_ops_ptr
	cbz	x0, 1f

	/* Get the cpu_ops cpu_reg_dump */
	ldr	x2, [x0, #CPU_REG_DUMP]
	cbz	x2, 1f
	blr	x2
1:
	mov	x30, x16
	ret
endfunc do_cpu_reg_dump
#endif

	/*
	 * The below function returns the cpu_ops structure matching the
	 * midr of the core. It reads the MIDR_EL1 and finds the matching
	 * entry in cpu_ops entries. Only the implementation and part number
	 * are used to match the entries.
	 * Return :
	 *     x0 - The matching cpu_ops pointer on Success
	 *     x0 - 0 on failure.
	 * Clobbers : x0 - x5
	 */
	.globl	get_cpu_ops_ptr
func get_cpu_ops_ptr
	/* Get the cpu_ops start and end locations */
	adr	x4, (__CPU_OPS_START__ + CPU_MIDR)
	adr	x5, (__CPU_OPS_END__ + CPU_MIDR)

	/* Initialize the return parameter */
	mov	x0, #0

	/* Read the MIDR_EL1 */
	mrs	x2, midr_el1
	mov_imm	x3, CPU_IMPL_PN_MASK

	/* Retain only the implementation and part number using mask */
	and	w2, w2, w3
1:
	/* Check if we have reached end of list */
	cmp	x4, x5
	b.eq	error_exit

	/* load the midr from the cpu_ops */
	ldr	x1, [x4], #CPU_OPS_SIZE
	and	w1, w1, w3

	/* Check if midr matches to midr of this core */
	cmp	w1, w2
	b.ne	1b

	/* Subtract the increment and offset to get the cpu-ops pointer */
	sub	x0, x4, #(CPU_OPS_SIZE + CPU_MIDR)
error_exit:
	ret
endfunc get_cpu_ops_ptr

#if DEBUG
	/*
	 * This function prints a warning message to the crash console
	 * if the CPU revision/part number does not match the errata
	 * workaround enabled in the build.
	 * Clobber: x30, x0 - x5
	 */
.section .rodata.rev_warn_str, "aS"
rev_warn_str:
	.asciz "Warning: Skipping Errata workaround for non matching CPU revision number.\n"

	.globl	print_revision_warning
func print_revision_warning
	mov	x5, x30
	/* Ensure the console is initialized */
	bl	plat_crash_console_init
	/* Check if the console is initialized */
	cbz	x0, 1f
	/* The console is initialized */
	adr	x4, rev_warn_str
	bl	asm_print_str
1:
	ret	x5
endfunc print_revision_warning
#endif