Booting Linux from QSPI on AMC1 with RFS on NFS

Preparation

Boot into U-Boot and stop execution by pressing a key

U-Boot 2017.01 (Nov 14 2017 - 13:37:55 +0100)

CPU  : AM437X-GP rev 1.2
I2C:   ready
DRAM:  512 MiB
MMC:   OMAP SD/MMC: 0, OMAP SD/MMC: 1
SF: Detected w25q64cv with page size 256 Bytes, erase size 4 KiB, total 8 MiB, m
apped at 30000000
In:    serial
Out:   serial
Err:   serial
Net:   cpsw
Hit any key to stop autoboot:  0
AMC1>

To boot a Linux Kernel from QSPI Flash you first need to load a Kernel and a DTB from either TFTP server or from USB stick and store these images on the QSPI Flash at suitable address offsets. Ref. to Serial FLASH mapping on AMC1.

Load Kernel Image and DTB

Use TFTP server

Network settings

To access the TFTP server you need to do a proper network configuration first. Either enter all necessary environment variables manually on the U-Boot command prompt or use script AMC1_NetConfig.ser to make all these settings automatically.

Required network settings:
eth1addr - own MAC address

   AMC1> setenv eth1addr c4:be:84:cb:1f:ff

ipaddr - own IP address

   AMC1> setenv ipaddr 192.168.168.197

serverip - remote server IP

   AMC1> setenv serverip 192.168.168.208

Load compressed Linux image from TFTP server

If all network settings are correct, a compressed Linux image can be loaded from TFTP server:

  tftpboot ${loadaddr} zImage-dsignt_amc1.bin

${loadaddr} is a pre-defined environment variable that specifies a free DDR RAM location for general purpose. We use it here as a temporary storage address for the TFTP transfer.

When the TFTP transfer succeeds, each received block (512 bytes) a '#' is printed on the terminal else a 'T' for timeout signals a problem connecting the server. A successful transmission can look like this (of course the IP addresses vary depending on your network configuration):

MC1> tftpboot ${loadaddr} zImage-dsignt_amc1.bin
link up on port 1, speed 1000, full duplex
Using cpsw device
TFTP from server 192.168.168.208; our IP address is 192.168.168.194
Filename 'zImage-dsignt_amc1.bin'.
Load address: 0x80200000
Loading: #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         ####################
         1.3 MiB/s
done
Bytes transferred = 3759704 (395e58 hex)
AMC1>

Load DTB from TFTP server

tftpboot ${fdtaddr} amc1.dtb

${fdtaddr} is a pre-defined environment variable that specifies a free DDR RAM location for general purpose. We use it here as a temporary storage address for the TFTP transfer.

AMC1> tftpboot ${fdtaddr} amc1.dtb
link up on port 1, speed 1000, full duplex
Using cpsw device
TFTP from server 192.168.168.208; our IP address is 192.168.168.194
Filename 'amc1.dtb'.
Load address: 0x88000000
Loading: #########
         1.2 MiB/s
done
Bytes transferred = 42545 (a631 hex)
AMC1>

Continue with step 3 Write Image and DTB to Flash

Use USB Stick

usb start and usb info

  usb start

Initialize the USB controler and enumerate all USB devices

AMC1> usb start
starting USB...
USB0:   Register 2000440 NbrPorts 2
Starting the controller
USB XHCI 1.00
scanning bus 0 for devices... 2 USB Device(s) found
AMC1>

  usb info

Print detailed information of enumerated devices

AMC1> usb info
1: Hub,  USB Revision 3.0
 - U-Boot XHCI Host Controller
 - Class: Hub
 - PacketSize: 9  Configurations: 1
 - Vendor: 0x0000  Product 0x0000 Version 1.0
   Configuration: 1
   - Interfaces: 1 Self Powered 0mA
     Interface: 0
     - Alternate Setting 0, Endpoints: 1
     - Class Hub
     - Endpoint 1 In Interrupt MaxPacket 8 Interval 255ms

2: Mass Storage,  USB Revision 2.0
 - USBest Technology USB Mass Storage Devie 1009135102477e
 - Class: (from Interface) Mass Storage
 - PacketSize: 64  Configurations: 1
 - Vendor: 0x1307  Product 0x0165 Version 1.0
   Configuration: 1
   - Interfaces: 1 Bus Powered 98mA
     Interface: 0
     - Alternate Setting 0, Endpoints: 3
     - Class Mass Storage, Transp. SCSI, Bulk only
     - Endpoint 1 Out Bulk MaxPacket 512
     - Endpoint 2 In Bulk MaxPacket 512
     - Endpoint 3 In Interrupt MaxPacket 64 Interval 8ms

AMC1>

Load compressed Linux image from USB stick

  fatload usb 0 ${loadaddr} zimage-dsignt_amc1.bin

Load Kernel image from USB mass storage device into RAM

AMC1> fatload usb 0 ${loadaddr} zimage-dsignt_amc1.bin
reading zimage-dsignt_amc1.bin
3759704 bytes read in 2080 ms (1.7 MiB/s)
AMC1>

Load DTB from USB stick

  fatload usb 0 ${fdtaddr} amc1.dtb

Load DTB from USB mass storage device into RAM

AMC1> fatload usb 0 ${fdtaddr} amc1.dtb
reading amc1.dtb
41451 bytes read in 44 ms (919.9 KiB/s)
AMC1>

Continue with step 3 Write Image and DTB to Flash

Write Image and DTB to Flash

sf probe

First check if a serial FLASH is available:

AMC1> sf probe
SF: Detected w25q64cv with page size 256 Bytes, erase size 4 KiB, total 8 MiB, m
apped at 30000000
AMC1>

sf erase

If the probe command finds a serial FLASH, use the erase command to clear the U-Boot FLASH area:

DTB:

AMC1> sf erase 0x120000 0x10000
SF: 65536 bytes @ 0x120000 Erased: OK
AMC1>

Linux Kernel (assumed filesize < 0x400000):

AMC1> sf erase 0x200000 0x400000
SF: 4194304 bytes @ 0x200000 Erased: OK
AMC1>

sf write

sf write writes a previously loaded image from RAM to serial FLASH

DTB:

AMC1> sf write ${fdtaddr} 0x120000 0x10000
device 0 offset 0x120000, size 0x10000
SF: 65536 bytes @ 0x120000 Written: OK
AMC1>

Linux Kernel:

AMC1> sf write ${loadaddr} 0x200000 0x400000
device 0 offset 0x200000, size 0x400000
SF: 4194304 bytes @ 0x200000 Written: OK
AMC1>

re-boot and load the image

After re-boot you need to probe for the SF first:

AMC1> sf probe
SF: Detected w25q64cv with page size 256 Bytes, erase size 4 KiB, total 8 MiB, m
apped at 30000000
AMC1>

Load Kernel and DTB from QSPI Flash

   sf read ${loadaddr} 0x200000 0x400000

   sf read ${fdtaddr} 0x120000 0x10000

AMC1> sf read ${loadaddr} 0x200000 0x400000
device 0 offset 0x200000, size 0x400000
SF: 4194304 bytes @ 0x200000 Read: OK
AMC1> sf read ${fdtaddr} 0x120000 0x10000
device 0 offset 0x120000, size 0x10000
SF: 65536 bytes @ 0x120000 Read: OK
AMC1>

Set bootargs

The global environment variable bootargs is automatically passed to the booting Linux. Make sure nfsroot points to the valid NFS path on your NFS server:

setenv bootargs root=/dev/nfs rw rootfstype=ext4 rootwait fixrtc  nfsroot=${serverip}:/home/sitara/ti-processor-sdk-linux-am437x-evm-04.01.00.06/targetNFS,vers=3 ip=${ipaddr}:${serverip}:${gatewayip}:${netmask}:${hostname}:${device}:${autoconf}

In this case with installed SDK 04.01.00.06 tools on server ${serverip} the correct path is:

${serverip}:/home/sitara/ti-processor-sdk-linux-am437x-evm-04.01.00.06/targetNFS

Boot Linux zImage

  bootz ${loadaddr} - ${fdtaddr}

AMC1> bootz ${loadaddr} - ${fdtaddr}
Kernel image @ 0x80200000 [ 0x000000 - 0x395e58 ]
## Flattened Device Tree blob at 88000000
   Booting using the fdt blob at 0x88000000
   Using Device Tree in place at 88000000, end 8800d630

Starting kernel ...

[    0.000000] Booting Linux on physical CPU 0x0
[    0.000000] Linux version 4.9.41-ge3a80a1c5c (sitara@sitara-sdk401)
...

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