Solve : How to access GPIO pin in ARM using low-level functions like i

1.	Solve : How to access GPIO pin in ARM using low-level functions like inb()/outb()??
Answer» In x86 platforms, inb()/outb() can be used to access GPIO pins efficiently. I am programming on ARM platform. I would like to access GPIO pins. It can be done by accessing virtual files under /sys/class/gpio, but this method is too slow. I wonder if there is any low-level functions like inb()/outb() to access GPIO pins in user mode application on ARM platform. You refer to low level functions found in C++ for Intel CPUs. Your ARM C libary is likely very different. Few here, if any, do work on ARM. Maybe you could provide some SPECIFIC details? Is this on a product that s widely used? Is it an Android platform? Without details, I am groping in the dark. Here is a recent tutorial no low-level Android stuff. Low Level Android Programming with AIDL, NDK and JNI — A 5 day course Does this even come close? This kind of stuff has a very narrow market, so the authors do not want to give away the material until they get some compensation for a lot of hard work. The platform is Ubuntu.Quote from: Stan Huang on DECEMBER 05, 2013, 09:21:32 PM The platform is Ubuntu. OK. Thee are a number of sites that are involved with Ubuntu on ARM https://wiki.ubuntu.com/ARM The above is one. Or just Google: Ubuntu on ARM You can port Ubuntu onto a Chrome book. (Video) https://www.youtube.com/watch?v=vpDtD4eKBB4 Somewhere out there are people doing what your want. Hope that helps a little bit. Quote ARM Processor ARM is a processor architecture used in a variety of APPLICATIONS, such as: Handheld Computers (Nokia n900, n95, etc.) Network Devices (Genesi Efika MX Nettop, Wyse T50, CompuLab TrimSlice, etc.) Project development boards (Beagleboard, Pandaboard, Quickstart, etc.) Subnotebooks (SHARP Netwalker, etc.) Netbook/Notebooks (Genesi Efika MX Smartbook, Toshiba AC100, etc.) Ubuntu targets the ARMv7 and above Application Processor family (Cortex A8, A9 and above). Currently the archive supports ARM EABI, with an expectation of minimum compliance with the ARMv7+VFP ISA. Where possible Ubuntu targets the Thumb2 instruction set. As to your original question. Input and Output instructions in the Intel instruction set a peculiar to Intel designs. Intel CPUs used in PCs are CISC designs, where as the ARM is a RISC design. So don't expect a similar tool for the ARM. Further reading: ARM Assembly Language Programming The ARM is memory mapped.

Solve : How to access GPIO pin in ARM using low-level functions like inb()/outb()??

Answer»

In x86 platforms, inb()/outb() can be used to access GPIO pins efficiently. I am programming on ARM platform. I would like to access GPIO pins. It can be done by accessing virtual files under /sys/class/gpio, but this method is too slow.
I wonder if there is any low-level functions like inb()/outb() to access GPIO pins in user mode application on ARM platform.
You refer to low level functions found in C++ for Intel CPUs. Your ARM C libary is likely very different. Few here, if any, do work on ARM.

Maybe you could provide some SPECIFIC details?
Is this on a product that s widely used?
Is it an Android platform?

Without details, I am groping in the dark.
Here is a recent tutorial no low-level Android stuff.

Low Level Android Programming with AIDL, NDK and JNI — A 5 day course

Does this even come close?

This kind of stuff has a very narrow market, so the authors do not want to give away the material until they get some compensation for a lot of hard work.

The platform is Ubuntu.Quote from: Stan Huang on DECEMBER 05, 2013, 09:21:32 PM

The platform is Ubuntu.

OK. Thee are a number of sites that are involved with Ubuntu on ARM
https://wiki.ubuntu.com/ARM
The above is one. Or just Google:
Ubuntu on ARM
You can port Ubuntu onto a Chrome book. (Video)
https://www.youtube.com/watch?v=vpDtD4eKBB4
Somewhere out there are people doing what your want.
Hope that helps a little bit.
Quote

ARM Processor
ARM is a processor architecture used in a variety of APPLICATIONS, such as:
Handheld Computers (Nokia n900, n95, etc.)
Network Devices (Genesi Efika MX Nettop, Wyse T50, CompuLab TrimSlice, etc.)
Project development boards (Beagleboard, Pandaboard, Quickstart, etc.)
Subnotebooks (SHARP Netwalker, etc.)
Netbook/Notebooks (Genesi Efika MX Smartbook, Toshiba AC100, etc.)
Ubuntu targets the ARMv7 and above Application Processor family (Cortex A8, A9 and above). Currently the archive supports ARM EABI, with an expectation of minimum compliance with the ARMv7+VFP ISA. Where possible Ubuntu targets the Thumb2 instruction set.

As to your original question. Input and Output instructions in the Intel instruction set a peculiar to Intel designs. Intel CPUs used in PCs are CISC designs, where as the ARM is a RISC design. So don't expect a similar tool for the ARM.
Further reading:
ARM Assembly Language Programming
The ARM is memory mapped.

Solve : How to access GPIO pin in ARM using low-level functions like inb()/outb()??

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