Before publishing its Videocore IV specification, Broadcom released an operating system independent binary blob. Does ARM Mali GPU has an abstraction layer independent of Linux kernel with an public interface specification?
The Linux kernel driver is released as full source code; there is no kernel-side binary blob. Source code for the kernel modules can be found here:
https://developer.arm.com/products/software/mali-drivers
... although silicon providers may provide customized releases for their chipsets (e.g. adding power management support), so ARM recommend getting the source via the chipset manufacturer. There is no non-Linux kernel driver available publicly to the best of my knowledge.
User-space library releases are binary only, available from the chipset manufacturer.
Related
I am developing my own OS and for days I’ve been wondering how to control video card, audio card to build a delicate GUI. It seems that the procedure is a bit different from that of controlling mouse or keyboard.
By the way,
1.How does an OS recognize hardware drivers?
2.Are all hardware drivers written for specific platforms (such as Windows,Linux,etc.)?
Still freshman in the university and failed to find relevant information
thanks for help =)
how to control video card
Graphics cards typically support a VGA mode and the VESA 2.0 standard. So this could be a good starting point for your first video driver.
How does an OS recognize hardware drivers?
Linux uses a device tree describing the hardware which has a compatible field for every item that needs a driver. All hardware drivers are kept in linker generated lists. If a driver has the same compatible value it can be used to drive the hardware. The linker list item is generated from a macro in the driver code using a specialized linker script.
Are all hardware drivers written for specific platforms (such as Windows, Linux, etc.)?
If you provide the right wrappers you may be able to reuse existing drivers. E.g. U-Boot reuses Linux drivers for USB devices. And the NDISwrapper can be used to run Windows WLAN drivers on Linux.
In the case of x86 the same (real mode) bootloader works on virtually any x86 device.
Is that possible on ARM or do I need to create a specific bootloader for each 'cortex'?
x86 or lets say PC compatible systems are ... pc compatible. They support the ancient bios calls so that there is massive compatibility. by design, by the chip vendor (intel) the software vendors (bios, operating system) and the motherboard vendors.
ARM is in now way shape or form like that. There are instruction sets you can choose that work almost or all the way across, but remember ARM systems you buy an ARM core and add it to your special chip, you and your special/custom stuff, then that is put on one or more different boards. There is little to no compatibility. Instruction set and arm core is a small part of the whole picture most of the code is for the non-arm stuff.
u-boot and perhaps others are fairly massive bootloaders, pretty much an operating system themselves, and have to be ported just like an operating system to each chip/board combination. The chip vendor, if this is a linux compatible system, most likely has a reference design and a BSP including a u-boot port and/or some other solution (rasberry pi is a good example). it is fairly trivial to boot linux or used to be, there is no reason for the massively overcomplicated u-boot. without a DTB you setup a few memory locations a register or two and branch to the kernel, thats it (again look at the raspberry pi), I assume with DTB you build the dtb then put it somewhere, setup a few registers and branch to the linux kernel (raspberry pi? ntc chip?)
There is a Arm open source project that can cover Armv7/v8 Cortex-A processors bootloaders.
https://git.trustedfirmware.org/TF-A/trusted-firmware-a.git/
Another open source project for Cortex-M processors:
https://git.trustedfirmware.org/TF-M/trusted-firmware-m.git/
In micro kernel system structure,hardware is not interact with the micro kernel.
So I want to know why micro-kernel of Windows NT doesn't directly interact with the hardware layer?
here is diagram what I am talking about
Mico kernel System structure
In a word: Portability
The NT microkernel is written in terms of the HAL (Hardware Abstraction Layer) to make it easy to port to mulitple target harware architectures. Now for the most part the HAL is very low level, and where possible compiles away to nothing (so the actual microkernel code is running directly on the hardware), or minimal inline asembly code.
DS-5 simulator uses a lot of terms like FVP, RTSM, Fast Models, Foundation Model, AEM Model, CADI. The explanation provided in Arm's documentation is not very clear. What do these terms mean and which ones should I care about as an end user of DS-5?
Model
An industry term for software simulation
In Arm's case, it is used interchangeably to either mean a component model (like a processor model) or an entire system/platform (like a VE FVP)
Fast Model
Software simulation of an individual component of a SOC like a processor or a peripheral
Usually provided as a shared library
Usually not seen by an end-user of DS-5.
Example: Cortex-A53 model.
Detailed docs - https://developer.arm.com/products/system-design/fast-models/docs
Cycle Models
Software simulation of an SoC including processor and peripherals
Cycle models are compiled directly from Arm RTL and retain complete functional accuracy
Instrumented to enable debug and analysis
Example: Multi-Cluster Arm Cortex-A53 with Coherent Interconnect, Interrupt Controller, Timer and UART
Virtual Platform (VP)
A virtual version of a real development board.
Usually provided as an executable.
Generic industry term.
Example: Android emulator
Fixed Virtual Platform (FVP)
Arm's term for its virtual platform.
Provided as an executable.
Not free, can be licensed from Arm.
Example: Quad-Core Cortex-A9 FVP, provided as part of DS-5, is not just a Cortex-A9 processor model, but a complete development platform containing Cortex-A9 4-core SoC simulation along with many peripherals.
Detailed docs - https://developer.arm.com/products/system-design/fixed-virtual-platforms/docs
RTSM
Stands for "Real Time System Model"
An old name for FVP.
The term RTSM is no longer actively used by Arm. They use FVP instead.
Foundation Model or Foundation Platform
A free virtual platform provided by Arm to kick-start Armv8 software development.
Minimal features - Only available on Linux, models a 'generic' Armv8 processor.
CADI
Stands for "Component Architecture Debug Interface" [Edited].
Arm specific term.
Simulator equivalent of the JTAG interface provided by real hardware.
DS-5 and other debuggers use CADI to talk to the Arm's virtual platforms.
I am having trouble with this question, somebody (hopefully mistakenly) moved the previous question to Unix/Linux list which has zero uclinux tagged questions. This is more of a embedded linux question..
I have a question about the footprint of uClinux. I have looked around to find a breakdown of requirements, there is no nice info on the net. The modules under interest are:
Core kernel TCPIP stack Serial Driver DHCP WiFi Support (any of the stack from vendors is ok) I am looking for RAM/Flash breakdown. I don't need a filesystem however there is a chance that I need it due to the driver model of Linux.
Bonus question: - Porting drivers from Linux to uClinux. I know the memory architecture is different. Considering driver doesn't do anything special wrt memory, could I just recompile the driver and expect it to work under uClinux?
I understand the drivers work pretty well. This driver has been ported to uClinux on Blackfin and STM32. http://www.sagrad.com/index.php?option=com_content&view=article&id=130&Itemid=130
The are running a sale on the ICs, Most of their modules that support WiFi and linux work with uClinux.