Date: Fri, 28 Sep 2018 09:12:05 -0700 From: John-Mark Gurney <jmg@funkthat.com> To: "Dr. Rolf Jansen" <rj@obsigna.com> Cc: freebsd-drivers@freebsd.org Subject: Re: Writing a PCIe-Driver Message-ID: <20180928161205.GN75530@funkthat.com> In-Reply-To: <B54DF398-9EA7-440A-BF44-0231642A1CF6@obsigna.com> References: <B54DF398-9EA7-440A-BF44-0231642A1CF6@obsigna.com>
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Dr. Rolf Jansen wrote this message on Sun, Sep 23, 2018 at 12:56 -0300: > A couple of years ago, with the valuable help of people on this list, I managed to write a PCI driver for the National Instruments DAQ card, NI PCI-6251. The driver was kept very simple, only map the BAR???s and some DMA memory into the user space. The DAC/ADC and DIO is then all controlled from user space by writing command codes to certain offsets from the mapped BAR???s, and reading data from the mapped DMA memory and/or from other given offsets. > > See: How to map device addresses into user space > https://lists.freebsd.org/pipermail/freebsd-drivers/2013-January/thread.html > > > Now, I need to do exactly the same for a PCIe card, namely the NI PCIe-6351. However, I even cannot see where to start. For PCI cards, the respective chapter 11 in the FreeBSD Architecture Handbook was quite helpful, for getting started, in no time, I got the PCI card probed and attached. > > https://www.freebsd.org/doc/en_US.ISO8859-1/books/arch-handbook/pci.html > > The dumb approach, probing the device ID and attaching the PCI(e) driver to the PCIe device in a similar fashion didn???t work - I didn???t expect this either, however, where would I start? How do I attach my driver to a PCIe card on FreeBSD 11 or 12? I'm a bit surprised that this didn't work, as PCIe is effectively backwards compatible w/ PCI except a few exceptions like MSI... Many drivers like em (sys/dev/e1000/if_em.c) are used for both PCI and PCIe cards.. Maybe look at what they are doing differently than your driver... > Please can somebody push me into the right direction. Once I got the driver attached to the card, I guess, I would be able to adapt the mem-mapping code of my old driver for the new card. -- John-Mark Gurney Voice: +1 415 225 5579 "All that I will do, has been done, All that I have, has not."help
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