On 06/16/2015 03:39 AM, Noralf Trønnes wrote: > > Den 16.06.2015 05:07, skrev Stephen Warren: >> On 06/13/2015 05:39 AM, Noralf Trønnes wrote: >>> This adds a new poweroff function to the watchdog driver for the >>> Raspberry Pi. Currently poweroff/halt results in a reboot. >>> >>> The Raspberry Pi firmware uses the RSTS register to know which >>> partiton to boot from. The partiton value is spread into bits >>> 0, 2, 4, 6, 8, 10. Partiton 63 is a special partition used by >>> the firmware to indicate halt. >>> >>> The firmware made this change in 19 Aug 2013 and was matched >>> by the downstream commit: >>> Changes for new NOOBS multi partition booting from gsh >> I don't understand why we need a new compatible value here; why not >> simply modify the existing bcm2835_power_off() function. That is written >> to do something that's interpreted by the RPi firmware, not something >> that the bcm2835 HW does. >> >> Admittedly the current name is a bit misleading, but fixing that should >> be a separate change to fixing the implementation to do what the current >> firmware expects. > > There are other boards that use the BCM2835 and I didn't want to break the > behaviour for those that use the reference firmware. We don't support those other board in mainline Linux AFAIK. In other discussions, Eric Anholt stated that the Roku 2 for example doesn't use the same firmware (albeit they were derived from the same base a long way back apparently) so I have no good reason to believe this logic is a standard across difference bcm2835 devices. Do you know more specific details? > Roku 2 device uses > this soc, and changing bcm2835_power_off() would break support for it. > ODROID-W also use BCM2835, but this is a Pi clone so I don't know if they > have matched their firmware behaviour to that of the Pi (admittedly not > many boards were made, their source of chips went dry). -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
