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by xihan94
Fri Aug 02, 2019 7:31 pm
Forum: Bare metal, Assembly language
Topic: Raspberry Pi 4
Replies: 59
Views: 16614

Re: Raspberry Pi 4

However that still means you can't have 32bit and 64bit on the same SD card because the config.sys entry needs to change which is still different to the situation up to the Pi3. In fact this was the situation with the RPi 3 before. You cannot have a kernel8.img on the SD card there and start in AAr...
by xihan94
Thu Aug 01, 2019 6:17 am
Forum: Bare metal, Assembly language
Topic: Raspberry Pi A72 Debug Interface
Replies: 0
Views: 1382

Raspberry Pi A72 Debug Interface

Hi, Cortex-A72 TRM specifies the debug component addresses to be: Address range Component  0x000000 - 0x00FFFF ROM table 0x010000 - 0x01FFFF Core 0 Debug 0x020000 - 0x02FFFF Core 0 CTI 0x030000 - 0x03FFFF Core 0 PMU 0x040000 - 0x04FFFF Core 0 Trace 0x050000 - 0x10FFFF Reserved 0x110000 - 0x11FFFF Co...
by xihan94
Sun Jul 28, 2019 8:54 pm
Forum: Bare metal, Assembly language
Topic: Status of U-Boot Support for Pi 4
Replies: 12
Views: 3843

Re: Status of U-Boot Support for Pi 4

epoch1970 wrote:
Sun Jul 28, 2019 9:47 am
There is no uboot forum AFAIK only a mailing list.

I think Andrei Gherzan is your man:
https://andrei.gherzan.ro/linux/uboot-on-rpi/
(he is also on this forum under the handle agherzan, look around.)
I didn’t know that wip branch. Thank you for sharing!
by xihan94
Sun Jul 28, 2019 8:53 pm
Forum: Bare metal, Assembly language
Topic: Status of U-Boot Support for Pi 4
Replies: 12
Views: 3843

Re: Status of U-Boot Support for Pi 4

swahren wrote:
Sun Jul 28, 2019 12:25 pm
The U-Boot guys are waiting for the results of the Linux upstreaming process.

But don't expect network or USB boot too soon. AFAIK there are no driver available.
Hey Stefan, this is exactly I was looking for. Thank you very much.
by xihan94
Sun Jul 28, 2019 5:55 am
Forum: Bare metal, Assembly language
Topic: Status of U-Boot Support for Pi 4
Replies: 12
Views: 3843

Status of U-Boot Support for Pi 4

Hi folks, does anyone of you know if there's a plan for 64bit U-Boot support for Pi 4? If someone can share discussion from U-Boot mailing list if there's any that will be very helpful.
by xihan94
Wed Dec 14, 2016 10:48 pm
Forum: Bare metal, Assembly language
Topic: Bare metal operation of the Bluetooth chip on Pi 3
Replies: 3
Views: 2456

Re: Bare metal operation of the Bluetooth chip on Pi 3

Hi rst, Thank you for sharing with me your precious experience. Beyond the fact itself, where do you find it is GPIO 32 and 33 that need to be set to ALT3 in order to connect the BT UART interface to the PL011? The BCM2835 document shows there is three sets of pins (14,15,16,17; 32,33,30,31; 36,37,3...
by xihan94
Wed Nov 09, 2016 10:23 pm
Forum: Bare metal, Assembly language
Topic: Bare metal operation of the Bluetooth chip on Pi 3
Replies: 3
Views: 2456

Bare metal operation of the Bluetooth chip on Pi 3

Hi folks, I am very interested in the Bluetooth chip of Pi 3 and would like to operate it in a bare metal environment. Currently, I've already had code for operating the PL011 UART to which the BCM43438 chip is connected. I've verified that the basic transmitting/receiving functionality work on PL01...
by xihan94
Wed Nov 02, 2016 5:55 pm
Forum: Bare metal, Assembly language
Topic: PL011 on Pi 3 Model B
Replies: 0
Views: 866

PL011 on Pi 3 Model B

Hi, I know that the bluetooth chip is connected to the PL011 UART on Pi 3. Is it the same UART as the one on Pi 1 (BCM2835)? Specifically, does it have DMA support? If there is substantial difference between the two chips, where may I find documentation besides the TRM for PL011 for the one on Pi 3?...
by xihan94
Wed Nov 02, 2016 5:18 pm
Forum: Bare metal, Assembly language
Topic: Raspberry Pi 3 Model B Timers
Replies: 9
Views: 9349

Re: Raspberry Pi 3 Model B Timers

Great illustration! Thanks Phil. I learned a lot from your response.
by xihan94
Wed Oct 19, 2016 9:58 pm
Forum: Bare metal, Assembly language
Topic: Raspberry Pi 3 Model B Timers
Replies: 9
Views: 9349

Re: Raspberry Pi 3 Model B Timers

Stop trying to find fault with the equation - it is correct, just not what you are expecting. If you think you've found a mistake then you haven't understood it. From a simple mathematical perspective, the original equation: timer_frequency = (2^31/prescaler) * input_frequency can be rewritten as: ...
by xihan94
Mon Sep 19, 2016 11:06 pm
Forum: Bare metal, Assembly language
Topic: Raspberry Pi 3 Model B Timers
Replies: 9
Views: 9349

Re: Raspberry Pi 3 Model B Timers

PhilE wrote:P.S. Multiplying by the reciprocal of a number is the same as dividing.
2^31 / <some number less than 2^31> * input_frequency isn't gonna "divide" the input frequency.

The reciprocal of that number, i.e., prescaler / 2^31, should be used.
by xihan94
Thu Sep 15, 2016 9:25 pm
Forum: Bare metal, Assembly language
Topic: Bare metal communication with the SMSC9514 USB controller
Replies: 4
Views: 1430

Re: Bare metal communication with the SMSC9514 USB controlle

Yes of course as any OS does that (an OS is just a program running on bare metal that provides services and abstractions to other programs). As for examples see: https://github.com/rsta2/uspi AND https://www.raspberrypi.org/forums/viewtopic.php?f=72&t=92579 AND https://github.com/ultibohub As well ...
by xihan94
Thu Sep 15, 2016 9:23 pm
Forum: Bare metal, Assembly language
Topic: what are the multicore sync interrupts on pi-2?
Replies: 5
Views: 1450

Re: what are the multicore sync interrupts on pi-2?

Good question, I would kind of be interested in the answer myself. With my multi core play I have not been thinking about using inturupts to sync the CPU's in any way, just using traditional async multi core methods, with traditional locks for shared data/code. I'm still studying low-level stuff. B...
by xihan94
Thu Sep 15, 2016 9:12 pm
Forum: Bare metal, Assembly language
Topic: Raspberry Pi 3 Model B Timers
Replies: 9
Views: 9349

Re: Raspberry Pi 3 Model B Timers

Hi Phil, Thank you for the response. I've dived more deeply into the BCM2836 document today https://www.raspberrypi.org/documentation/hardware/raspberrypi/bcm2836/QA7_rev3.4.pdf . There is a crystal oscillator running at 19.2 MHz on the board. It can be the source of the ARM clocks. Another clock, t...
by xihan94
Thu Sep 15, 2016 2:20 am
Forum: Bare metal, Assembly language
Topic: Assembly Language Access to UART on Rpi3
Replies: 11
Views: 6053

Re: Assembly Language Access to UART on Rpi3

Hi Dave, I believe David Welch has several examples exactly for Pi 3, and in AArch64 mode. https://github.com/dwelch67/raspberrypi/tree/master/boards/pi3/aarch64/uart02 He also has one uart example in AArch32 mode. https://github.com/dwelch67/raspberrypi/tree/master/boards/pi3/aarch32/HYP/uart05 Hop...
by xihan94
Wed Sep 14, 2016 11:43 pm
Forum: Bare metal, Assembly language
Topic: Raspberry Pi 3 Model B Timers
Replies: 9
Views: 9349

Raspberry Pi 3 Model B Timers

Hi folks,

Since BCM2837 is a cortex-A53, it should have architected timers accessible through CNT* registers. Does Pi 3 have one for each core? Are they free running or derived from the GPU timers as before? If latter is the case, what's the formula for calculating this clock rate?

Thanks,
Xi
by xihan94
Wed Sep 14, 2016 11:41 pm
Forum: Bare metal, Assembly language
Topic: Bare metal communication with the SMSC9514 USB controller
Replies: 4
Views: 1430

Re: Bare metal communication with the SMSC9514 USB controlle

Yes of course as any OS does that (an OS is just a program running on bare metal that provides services and abstractions to other programs). As for examples see: https://github.com/rsta2/uspi AND https://www.raspberrypi.org/forums/viewtopic.php?f=72&t=92579 AND https://github.com/ultibohub As well ...
by xihan94
Tue Sep 13, 2016 1:33 am
Forum: Bare metal, Assembly language
Topic: Bare metal communication with the SMSC9514 USB controller
Replies: 4
Views: 1430

Bare metal communication with the SMSC9514 USB controller

Hi folks,

How can I communicate with the USB/Ethernet controller directly in bare metal environment? Googling gave me nothing. Any pointer to some documentation/source code may help.

Thank you in advance.
by xihan94
Fri Jul 29, 2016 5:35 am
Forum: Bare metal, Assembly language
Topic: Simple bare metal code on RPi 3 doesn't work
Replies: 2
Views: 919

Re: Simple bare metal code on RPi 3 doesn't work

With a brief glance, you seem to have set GPIO 16 to mode ALT3 or CTS0 with the 'mov r1, #7' rather than an output. It probably should be 'mov r1, #1' instead setting the mode to output. GPIO 16 should be header pin 36. Sorry, I regarded the PM button as quoting and replying. I'm new to Raspberry P...
by xihan94
Thu Jul 28, 2016 10:20 pm
Forum: Bare metal, Assembly language
Topic: Simple bare metal code on RPi 3 doesn't work
Replies: 2
Views: 919

Simple bare metal code on RPi 3 doesn't work

My disassembled code is as shown below. Basically, I want to turn on GPIO 16. I used a multimeter to measure voltage between GPIO(BCM) 16 and GND. It was unexpectedly 0V. What could be wrong? Note: I made the binary using objcopy, so it was a raw binary running on the Pi. 00008000 <_start>: 8000: e5...

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