Registering Soft IPs as Devices for Linux

1

I am trying to use an SPI bus between HPS and FPGA in order to communicate with a module (which is not directly connected to the HPS). The communication path looks like this:

[HPS] <===(Lightweight Bridge)===> [SPI (Soft IP, inside FPGA)] <===(SPI)===>[Sensor Module]

From what I understand, I should open /dev/mem and do mmap() in order to access the Soft IP’s registers. It seems so challenging and I don’t have much time.

But when a peripheral chip/module is connected to the HPS directly, with drivers and device tree settings, Linux can see it as a device and it appears under /dev/ folder. So, we can use read-write-ioctl system calls to easily communicate with it.

My question is, is there any way to make this SPI Soft IP appear in Linux’s /dev/ file for the ease of communication using system calls? Other than this, I am a newbie in this subject and if any of the above sounds silly, a warning is always appreciated.

Thanks in advance.

2

If you want the OS to recognize the existence of the SPI core, you need to add it to the device tree.

Once that’s done, if the SPI core has a linux driver, the driver should be able to find it as well (if it’s built-in, or loaded into the kernel), and make your life a lot easier. Better still, your external device may also have a driver. Hunt through the /drivers/ portion of the kernel tree and you might get lucky.