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by arjunhary
Fri Sep 16, 2016 2:35 pm
Forum: Bare metal, Assembly language
Topic: Trying Bare Metal on Raspberry Pi 2
Replies: 98
Views: 34796

Re: Trying Bare Metal on Raspberry Pi 2

I am sorry i did not post the last question correctly. It was not on core synchronization or volatile. Let me give this another shot. my question was on caching of variables and where do the variables go. 1) previously i had the cache setup in write through mode(Page table flags were set to 0x1540A ...
by arjunhary
Fri Sep 16, 2016 4:03 am
Forum: Bare metal, Assembly language
Topic: Trying Bare Metal on Raspberry Pi 2
Replies: 98
Views: 34796

Re: Trying Bare Metal on Raspberry Pi 2

1) I got the MMU on multi core working. My mistake was not setting up the stack correctly. Once i set the stack correctly for all the cores, i can see that MMU and caches are enabled. I also learnt that declaring a variable as volatile makes it uncacheable or atleast that is the behavior i see. i ha...
by arjunhary
Wed Sep 14, 2016 6:33 pm
Forum: Bare metal, Assembly language
Topic: Trying Bare Metal on Raspberry Pi 2
Replies: 98
Views: 34796

Re: Trying Bare Metal on Raspberry Pi 2

1) I checked the AUX control register and smp bit is on by default (Bit 6)
2) Since it is an MMU per core, I assume there is a separate page table per core. So the MMU init sequence has to be called per core correct?
by arjunhary
Wed Sep 14, 2016 3:09 am
Forum: Bare metal, Assembly language
Topic: Trying Bare Metal on Raspberry Pi 2
Replies: 98
Views: 34796

Re: Trying Bare Metal on Raspberry Pi 2

Hi, I am trying to get the MMU working with multi core but have a few basic questions. I am following the examples posted by mrvn at his github site. I have MMU working with single core and also multi core boot working but i am running into some issues with multi core MMU. 1) Very basic question. Is...
by arjunhary
Thu Mar 10, 2016 8:21 pm
Forum: Bare metal, Assembly language
Topic: RPi 2 and OpenOCD
Replies: 25
Views: 13930

Re: RPi 2 and OpenOCD

BTW . I have the SPI working in polling mode. Just trying to see if i can get it to work through the DMA.
by arjunhary
Thu Mar 10, 2016 8:19 pm
Forum: Bare metal, Assembly language
Topic: RPi 2 and OpenOCD
Replies: 25
Views: 13930

Re: RPi 2 and OpenOCD

I have not yet tried to eliminate gdb, I will try that later this week.Question on the DMA though. I read that the DMA control block should use bus address (Starting with 0xc0 in my case since l2 cache is disabled) . Should the source and destination address be bus addresses too? I tried an example ...
by arjunhary
Thu Mar 10, 2016 3:53 pm
Forum: Bare metal, Assembly language
Topic: RPi 2 and OpenOCD
Replies: 25
Views: 13930

Re: RPi 2 and OpenOCD

Even when i use the arm to set memory it does not trigger. When openocd starts it displays the following, which i assume means it has 4 watchpoints though your point that it may not be enabled makes sense. Info : bcmrpi2.cpu0: hardware has 6 breakpoints, 4 watchpoints Info : bcmrpi2.cpu1: hardware h...
by arjunhary
Thu Mar 10, 2016 5:17 am
Forum: Bare metal, Assembly language
Topic: RPi 2 and OpenOCD
Replies: 25
Views: 13930

Re: RPi 2 and OpenOCD

It does not work in the arm address space as well or on local as well as global variables. My code does not use the GPU as far as i know. I set a watchpoint on a RAM location and change it in the program and the watchpoint still does not trigger.
by arjunhary
Fri Mar 04, 2016 7:45 pm
Forum: Bare metal, Assembly language
Topic: RPi 2 and OpenOCD
Replies: 25
Views: 13930

Re: RPi 2 and OpenOCD

Hi, I am using openocd and gdb with RPI2 to do bare metal programming. I used the example setup from dwelch67 and have been using that setup to download and debug programs for a while. I recently have been trying to get SPI working with DMA on baremetal for the piTFT and have been trying to use watc...
by arjunhary
Fri Mar 04, 2016 7:28 pm
Forum: Bare metal, Assembly language
Topic: RPi 2 and OpenOCD
Replies: 25
Views: 13930

Re: RPi 2 and OpenOCD

Hi, I am using openocd with gdb to load and debug program on the RPI2. I followed the examples from dwelch67/ I am able to do all of the gdb features except watch points. All my breakpoints work and code breaks correctly. But when i set watch points on memory location and also variables, it does not...

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