Re: [PATCH v2 1/3] drivers: misc: intel_sysid: Add sysid from arch to drivers

Greg KH
2022-07-28T07:57:26Z

On Thu, Jul 21, 2022 at 08:31:50PM +0800, kah.jing.lee@intel.com wrote:
> From: Kah Jing Lee <kah.jing.lee@intel.com>
>
> Add new sysid driver. The Altera(Intel) Sysid component is generally part
> of an FPGA design. The component can be hotplugged when the FPGA is
> reconfigured. This driver support the component being hotplugged.
> The sysid driver stores unique 32-bit id value which is similar to a
> check-sum value; different components, different configuration options,
> or both, can be configured to produce different id values. Timestamp field
> is the unique 32-bit value that is based on the system generation time.

I really do not understand what this driver does at all, sorry. It only
exports 2 sysfs files. Who will use those sysfs files? What are they
for? Why is a driver needed at all as all you are doing is reading 2
memory values from the device, right? Why is the kernel responsible for
doing the data conversion logic and not userspace?

> There are two basic ways to use the system ID core:
> - Verify the system ID before downloading new software to a system. This
> method can be used by software development tools, before downloading a
> program to a target hardware system, if the program is compiled for
> different hardware.

verify it how? This is just a random value that we have no idea how to
treat it.

> - Check system ID after reset. If a program is running on hardware other
> than the expected Platform Designer system, the program may fail to
> function altogether. If the program does not crash, it can behave
> erroneously in subtle ways that are difficult to debug. To protect against
> this case, a program can compare the expected system ID against the system
> ID core, and report an error if they do not match.

Where are these ids listed to be able to verify anything?

What userspace tools use this new driver?

thanks,

greg k-h