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by ChrisYin
Thu Nov 15, 2018 3:32 pm
Forum: Bare metal, Assembly language
Topic: information of bcm2835 mailbox and doorbell
Replies: 6
Views: 2428

Re: information of bcm2835 mailbox and doorbell

It's possible that there are config and status registers but without any further information there is no way to know, for the VCHIQ the ARM sends a mailbox message to the GPU to start the protocol and it's possible that the GPU does some configuration of the device during that process. Of course th...
by ChrisYin
Mon Nov 12, 2018 3:28 pm
Forum: Bare metal, Assembly language
Topic: information of bcm2835 mailbox and doorbell
Replies: 6
Views: 2428

Re: information of bcm2835 mailbox and doorbell

The only thing I know of that uses the doorbell (at 0xb840) as opposed to the mailbox (at 0xb880) is the VCHIQ driver which uses it to initiate an interrupt that signals the other side of an event. It doesn't really document the device or what the bits mean but it does give a tiny bit of informatio...
by ChrisYin
Mon Nov 12, 2018 3:16 pm
Forum: Bare metal, Assembly language
Topic: information of bcm2835 mailbox and doorbell
Replies: 6
Views: 2428

Re: information of bcm2835 mailbox and doorbell

Careful there are two sets of mailboxes and doorbells, you would need to emulated both correctly The core mailboxes and doorbells are detailed in https://www.raspberrypi.org/documentation/hardware/raspberrypi/bcm2836/QA7_rev3.4.pdf The system has sixteen mailboxes, four for each core. The system ha...
by ChrisYin
Thu Nov 08, 2018 7:58 pm
Forum: Bare metal, Assembly language
Topic: information of bcm2835 mailbox and doorbell
Replies: 6
Views: 2428

information of bcm2835 mailbox and doorbell

Hi, everyone. Currently I'm working on virtualization technology in Raspberry Pi3 board. I want to emulate the firmware of the Pi3 board., including bcm2835 mailbox, doorbell, board property, power management, etc. But I could not find any useful information about the bcm2835-doorbell in its documen...
by ChrisYin
Tue May 15, 2018 9:14 pm
Forum: Bare metal, Assembly language
Topic: multi-core shared memory communication
Replies: 15
Views: 3748

Re: multi-core shared memory communication

Hi, deater I'm also working on bare metal things in Pi3. I've successfully booted four cores, but only two of them can open its mmu successfully (one BSP and one AP). It's really strange. Why other cores don't work with the same codes? I just curious about how to initialize mmu in multicores? Do the...

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