Changes between Version 28 and Version 29 of newport

Timestamp:

12/21/2017 10:50:25 PM (8 years ago)

Author:

Ryan Erbstoesser

Comment:

add info for booting to microsd for kernel/rootfs

newport

@@ -353 +353 @@
 
 The bootloader also has a notion of boot device, either the built in eMMC or an external microSD.
-This is controlled through the UBoot variable 'dev'.
+This is controlled through the UBoot variable 'dev'. The dev variable is purely for the bootloader, and does not signify what device to boot the kernel/rootfs from.
 
 Note if booting with the onboard eMMC as the primary boot device, “0/mmcblk0” is the U-Boot/Linux device node for eMMC and “1/mmcblk1” is the U-Boot/Linux device node for microSD. When booting from the alternate device (microSD) this is swapped. 
+
+=== Booting to a kernel/rootfs on the microSD ===
+
+This assumes the bootloader will remain on the eMMC, but then we switch to the microSD for the kernel/rootfs.
+
+Run the following commands in the uboot bootloader command prompt on the Newport SBC serial console:
+
+#This tells the board to always get the bootloader from emmc, which is ok.
+{{{
+setenv dev 0
+}}}
+
+#now we are going to create a NEW script called boot_sd for booting from the microSD: 
+#note the ext4load command grabs from 1:2, which means dev 1, which will be the microSD as long as you set 
+#dev to 0 above (meaning dev 0 will be emmc, which will hold the bootloader, and then 1 would be the microSD)
+{{{
+setenv boot_sd  "ext4load mmc 1:2 ${kernel_addr} boot/${kernel} && setenv root '/dev/mmcblk0p2 rw rootwait' && run setargs && booti ${kernel_addr} - ${fdtcontroladdr}"
+}}}
+
+#now save everything
+{{{
+saveenv
+}}}
+
+#now boot to microSD
+{{{
+run boot_sd
+}}}
+
+If you want to then start doing this automatically everytime, you would look at the variable called boot_cmd. It currently uses the built in script we have to boot from mmc (which means emmc)
+{{{
+GW6304-B> print bootcmd
+bootcmd=run boot_mmc
+}}}
+
+#if you want to modify this to boot from your new script:
+{{{
+setenv bootcmd 'run boot_sd'
+saveenv
+reset
+}}}
+
+
+
+
 
 [=#bootloader]