Pointers for writing a good PCIe driver

From: Mason <slash.tmp@free.fr>
To: Bjorn Helgaas <bhelgaas@google.com>
Cc: linux-pci <linux-pci@vger.kernel.org>
Subject: Pointers for writing a good PCIe driver
Date: Mon, 6 Feb 2017 16:54:08 +0100	[thread overview]
Message-ID: <ff099b5f-efc8-bb5f-41e3-493398844cc0@free.fr> (raw)

Hello,

My platform ( arch/arm/mach-tango ) provides a PCIe controller from PLDA.

I do have access to a driver that works for a few PCIe boards, but it's
an ancient out-of-tree driver (targeting v3.4). Also, I'm not sure it
follows the best-practice guidelines (e.g. it hard-codes a few
work-arounds directly in drivers/pci/probe.c)

If I understand correctly, while PCIe is a standard, it is not codified
as much as USB (XHCI) or SATA (AHCI), which means the register layout
(and possibly other things) are left up to the integrator? Which means
there cannot be some kind of "generic" driver that works for a random
PCIe controller?

I guess my main question is: do you have pointers on getting started
writing a PCIe driver good enough for upstream?

Is Documentation/PCI/PCIEBUS-HOWTO.txt still a relevant resource?

Are there good resources to get up to speed on the PCIe terminology?

Regards.