Re: [RFC] RNG rewrite...

From: Jeff Garzik
Date: Sat Oct 15 2005 - 05:42:13 EST

Deepak Saxena wrote:
I want to add support for the RNG on Intel's IXP4xx NPU and looking at the existing hw-random.c code, it is written with
the assumption that the RNG is on the PCI bus. I can put a
big #ifdef ARCH_IXP4XX in there but instead I would rather
rewrite the damn thing to use the device model and have a rng
device class with individual drivers for each RNG model, including
IXP4xx. I'll keep the miscdev interface around but will add a
new interface under /sys/class/rng that the userspace tools can transition to. Is this OK with folks?

How does the hardware export RNG functionality? CPU insn? Magic memory address? Can it be done 100% in userspace?

One question I have is about the following comment:

* This data only exists for exporting the supported
* PCI ids via MODULE_DEVICE_TABLE. We do not actually
* register a pci_driver, because someone else might one day
* want to register another driver on the same PCI id.

Why? Is there something else on those IDs that another driver might
care about?

They are bridge ids, not device ids.


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