System boot and recovery via microSD card (BELK/BXELK)

Info Box Applies to Bora Applies to BORA Xpress

History

Version	Date	BELK version	Notes
1.0.0	November 2015	3.0.0	First release

Introduction

BELK provides a bootable microSD that can be used not only to quickly start the system, but also as a recovery method in case the primary boot device (eg. QSPI NOR flash) gets erased or corrupted. The following sections describe how to create a bootable SD card and how to configure the system for booting from SD.

How to create a bootable MicroSD card

This section describes how to create a new bootable microSD card from scratch. The following components must be available:

• FSBL built with Vivado 2014.4 as described here
• U-boot built in elf format, as described in here
• FPGA bitstream (optional).

The procedure is the following:

• from the Vivado 2014.4 SDK, apply the required patches to the main.c project file.This step can be done in two ways:
  • manually, directly modifying the main.c file adding the following code snippets:

----CUT----
	/*
	 * Unlock SLCR for SLCR register write
	 */
	SlcrUnlock();

+	*((u32 *)0xF8000830) = 0x003F003F;
+	*((u32 *)0xF8000834) = 0x003F003F;

	/* If Performance measurement is required 
	 * then read the Global Timer value , Please note that the
----CUT----

----CUT----
	/*
	 * Read bootmode register
	 */
	BootModeRegister = Xil_In32(BOOT_MODE_REG);
	BootModeRegister &= BOOT_MODES_MASK;

+	// always init QSPI
+	InitQspi();
	
	/*
	 * QSPI BOOT MODE
	 */
#ifdef XPAR_PS7_QSPI_LINEAR_0_S_AXI_BASEADDR
----CUT----

• • automatically, using the Apply Patch function and selecting the belk-sd-boot.patch file provided with the BELK (please refer to the following images):

Automatic patch applying (1/3)

Automatic patch applying (2/3)

Automatic patch applying (3/3)

• once the patch is applied, rebuild the FSBL project
• from the Xilinx Tools menu, select Create Zynq Boot Image
• select Create New BIF file and insert path and name of the .bif file
• in the Boot image partitions section, click on Add to browse and add the following files:
  • FSBL in .elf format, with bootloader as partition type
  • (optional) FPGA bitstream in .bit format, with partition type datafile
  • U-boot binary with .elf extension, with partition type datafile
• in the Output path section, browse and select the path where saving the boot.bin file
• on a PC, format the microSD card creating a FAT32 partition
• copy the boot.bin file to the microSD card FAT32 partition.

How to configure the system for microSD boot

The S5 dip-switch on the BORAEVB carrier board is used for configuring the boot mode. Please refer to the following table to select the MicroSD mode (highlighted in green):

Boot mode	S5 dip switch positions
	1	2	3	4	5	6	7	8
MicroSD	OFF	ON	OFF	ON	ON	OFF	ON	OFF
NOR SPI	OFF	ON	OFF	ON	ON	ON	ON	OFF
NAND	OFF	ON	OFF	ON	ON	OFF	ON	ON