Changes between Version 6 and Version 7 of gsc/alternate_boot_device

Timestamp:

07/22/2024 07:18:37 PM (4 months ago)

Author:

Tim Harvey

Comment:

added details about setting the boot device

gsc/alternate_boot_device

@@ -3 +3 @@
 = Alternate Boot Device
 Some Gateworks family products have an 'Alternate boot device' that can be used for alternate firmware images, such as a flash recovery image:
- * Newport - eMMC vs microSD
+ * Newport - eMMC (primary) vs microSD (alternate)
 
+[=#auto-switch-boot]
 == Auto Switch Boot Device
 The [wiki:gsc Gateworks System Controller] implements an 'Auto Switch Boot Device' feature that can be useful as a firmware recovery mechanism. GSC register R1.6 (SWITCH_BOOT_ENABLE) enables this mode. When this is set and the board powers on it will initiate a countdown timer cleared by the boot firmware that expires in 30 seconds. Therefore if the boot firmware is missing/corrupt the board will power cycle and boot off the alternate device.
@@ -17 +18 @@
 i2c dev 0 && i2c mw 0x20 1 0x40 1     ;# enable R1.6 (SWITCH_BOOT_ENABLE)
 }}}
+
+== Current Boot Device
+The current boot device is held in GSC register R21 (0x15) with a value of 0 being primary and a value of 1 being alternate. This value will be toggled by the 'Auto Switch Boot' feature [wiki:gsc/#auto-switch-boot above] but can also be manually set:
+
+From Linux:
+ * Alternate
+{{{#!bash
+i2cset -f -y 0 0x20 0x15 1 # set boot device to 1 (alternate)
+}}}
+ * Primary
+{{{#!bash
+i2cset -f -y 0 0x20 0x15 0 # set boot device to 0 (primary)
+}}}
+
+U-Boot:
+ * Alternate:
+{{{#!bash
+i2c dev 0 && i2c mw 0x20 0x15 1 # set boot device to 1 (alternate)
+}}}
+ * Primary:
+{{{#!bash
+i2c dev 0 && i2c mw 0x20 0x15 0 # set boot device to 0 (primary)
+}}}