Kontron Bootloader Environment Extensions; Bootloader Mass Storage Support; Qspi Flash; Sd Card And Emmc Devices - Kontron PITX-IMX8M User Manual

7.7. Kontron Bootloader Environment Extensions

To support PITX-iMX8M board properly, Kontron adds some environment variables to the standard set of variables
provided by mainline U-Boot. These variables are shown below.

Table 39: Bootloader Environment Extensions

Variable Value
boot_sel Depends on
BOOT_SEL
lines
core_variant d
s
eth1addr From EEPROM
ethaddr From EEPROM
fdt_addr
0x83000000
panel Default: ld101
pcie_a_prsnt yes
pcie_b_prsnt yes
pcie_c_prsnt yes
pwm_out_disable
yes
serial# From EEPROM
Variables from the table above marked in bold are set automatically each time U-Boot
starts. They will override different settings possibly stored in persistent environment.

7.8. Bootloader Mass Storage Support

U-Boot provides support to read and write from mass storage devices like


QSPI flash

 eMMC device
 SD card
 USB thumb device
7.8.1. QSPI flash
QSPI flash is accessed using the "sf" command
Example: Load one sector (64K) from SPI flash
=> sf probe 0
=> sf read ${loadaddr} 0 10000

7.8.2. SD Card and eMMC Devices

eMMC and SD card are accessed using the "mmc" command
Example: Load 256 blocks from eMMC
=> mmc dev 1
Description
BOOT_SEL lines from carrier are evaluated during startup and
boot_sel is set appropriately. See chapter 7.11 Bootloader Boot
Source for more detail
Set to "s" for i.MX7S module, "d" for i.MX7D module.
Ethernet port FEC1 MAC address
Ethernet port FEC0 MAC address
Memory location for device tree blob
Describes the panel type attached to the module. It is used to select
the appropriate device tree file
Enable/disable PCIE_A PRSNT line to reduce power consumption
Enable/disable PCIE_B PRSNT line to reduce power consumption
Enable/disable PCIE_C PRSNT line to reduce power consumption
Enable/disable PWM_OUT signal. When disabled, GPIO5 pin is used
as GPIO.
Module serial number
pITX-iMX8M – Rev. 0.7 Preliminary
www.kontron.com // 57