warp7: Add initial warp7_helpers.S

This commit adds a warp7_helpers.S which contains a implementation of:

- platform_mem_init
- plat_get_my_entrypoint
- plat_crash_console_init
- plat_crash_console_putc
Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>

plat/imx/imx7/warp7/aarch32/warp7_helpers.S

+/*
+ * Copyright (c) Linaro 2018 Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <arch.h>
+#include <asm_macros.S>
+#include <assert_macros.S>
+#include <platform_def.h>
+
+	.globl	platform_mem_init
+	.globl	plat_get_my_entrypoint
+	.globl	plat_crash_console_init
+	.globl	plat_crash_console_putc
+
+	/* ---------------------------------------------
+	 * int plat_mem_init(void)
+	 * Function to initialize memory.
+	 * The HAB hands off the DDR controller already
+	 * setup and ready to use.
+	 * Implement the mandatory function as a NOP
+	 * ---------------------------------------------
+	 */
+func platform_mem_init
+	bx	lr
+endfunc platform_mem_init
+
+func plat_get_my_entrypoint
+	mov	r0, #0
+	bx	lr
+endfunc plat_get_my_entrypoint
+
+func plat_crash_console_init
+	mov_imm	r0, PLAT_WARP7_BOOT_UART_BASE
+	mov_imm	r1, PLAT_WARP7_BOOT_UART_CLK_IN_HZ
+	mov_imm	r2, PLAT_WARP7_CONSOLE_BAUDRATE
+	b	imx_crash_uart_init
+endfunc plat_crash_console_init
+
+func plat_crash_console_putc
+	mov_imm r1, PLAT_WARP7_BOOT_UART_BASE
+	b	imx_crash_uart_putc
+endfunc plat_crash_console_putc