imx: mx7: Add plugin support

Add mx7_plugin.S which calls boot rom setup function, generate the second ivt,
and jump back to boot rom.

Signed-off-by: Peng Fan <peng.fan@nxp.com>
Signed-off-by: Ye Li <ye.li@nxp.com>
Cc: Stefano Babic <sbabic@denx.de>
Reviewed-by: Tom Rini <trini@konsulko.com>

arch/arm/include/asm/arch-mx7/mx7_plugin.S

@@ -0,0 +1,111 @@
+/*
+ * Copyright (C) 2016 Freescale Semiconductor, Inc.
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <config.h>
+
+#define ROM_API_TABLE_BASE_ADDR_LEGACY		0x180
+#define ROM_VERSION_OFFSET               	0x80
+#define ROM_API_HWCNFG_SETUP_OFFSET		0x08
+
+plugin_start:
+
+	push    {r0-r4, lr}
+
+	imx7_ddr_setting
+	imx7_clock_gating
+	imx7_qos_setting
+
+/*
+ * Check if we are in USB serial download mode and immediately return to ROM
+ * Need to check USB CTRL clock firstly, then check the USBx_nASYNCLISTADDR
+ */
+	ldr r0, =0x30384680
+	ldr r1, [r0]
+	cmp r1, #0
+	beq normal_boot
+
+	ldr r0, =0x30B10158
+	ldr r1, [r0]
+	cmp r1, #0
+	beq normal_boot
+
+	pop {r0-r4, lr}
+	bx lr
+
+normal_boot:
+
+/*
+ * The following is to fill in those arguments for this ROM function
+ * pu_irom_hwcnfg_setup(void **start, size_t *bytes, const void *boot_data)
+ * This function is used to copy data from the storage media into DDR.
+ * start - Initial (possibly partial) image load address on entry.
+ *         Final image load address on exit.
+ * bytes - Initial (possibly partial) image size on entry.
+ *         Final image size on exit.
+ * boot_data - Initial @ref ivt Boot Data load address.
+ */
+	adr r0, boot_data2
+	adr r1, image_len2
+	adr r2, boot_data2
+
+/*
+ * check the _pu_irom_api_table for the address
+ */
+before_calling_rom___pu_irom_hwcnfg_setup:
+	ldr r3, =ROM_VERSION_OFFSET
+	ldr r4, [r3]
+	ldr r3, =ROM_API_TABLE_BASE_ADDR_LEGACY
+	ldr r4, [r3, #ROM_API_HWCNFG_SETUP_OFFSET]
+	blx r4
+after_calling_rom___pu_irom_hwcnfg_setup:
+
+
+/* To return to ROM from plugin, we need to fill in these argument.
+ * Here is what need to do:
+ * Need to construct the paramters for this function before return to ROM:
+ * plugin_download(void **start, size_t *bytes, UINT32 *ivt_offset)
+ */
+	pop {r0-r4, lr}
+	push {r5}
+	ldr r5, boot_data2
+	str r5, [r0]
+	ldr r5, image_len2
+	str r5, [r1]
+	ldr r5, second_ivt_offset
+	str r5, [r2]
+	mov r0, #1
+	pop {r5}
+
+	/* return back to ROM code */
+	bx lr
+
+/* make the following data right in the end of the output*/
+.ltorg
+
+#define FLASH_OFFSET 0x400
+
+/*
+ * second_ivt_offset is the offset from the "second_ivt_header" to
+ * "image_copy_start", which involves FLASH_OFFSET, plus the first
+ * ivt_header, the plugin code size itself recorded by "ivt2_header"
+ */
+
+second_ivt_offset:      .long (ivt2_header + 0x2C + FLASH_OFFSET)
+
+/*
+ * The following is the second IVT header plus the second boot data
+ */
+ivt2_header:            .long 0x0
+app2_code_jump_v:       .long 0x0
+reserv3:                .long 0x0
+dcd2_ptr:               .long 0x0
+boot_data2_ptr:         .long 0x0
+self_ptr2:              .long 0x0
+app_code_csf2:          .long 0x0
+reserv4:                .long 0x0
+boot_data2:             .long 0x0
+image_len2:             .long 0x0
+plugin2:                .long 0x0