kern/134878: [puc] [patch] Add support for Oxford OXPCIe954 and OXPCIe958 PCI Express chips

[David Wood]

The following reply was made to PR kern/134878; it has been noted by GNATS.

From: David Wood <david at wood2.org.uk>
To: blortz at pacbell.net
Cc: bug-followup at FreeBSD.org
Subject: Re: kern/134878: [puc] [patch] Add support for Oxford OXPCIe954 and OXPCIe958 PCI Express chips
Date: Mon, 9 Nov 2009 21:44:57 +0000

 Hi Bill,
 
 Thanks for your follow-up for my patch.
 
 In message <01b201ca60a6$0f633d00$2e29b700$@net>, Bill Lortz 
 <blortz at pacbell.net> writes
 >I have the FreeTech PCI-e mini card with 1 serial and 1 parallel port (part
 >#PEX1S1PMINI) that claims to use the Oxford OXPCIe952 chip.   The computer
 >is a FITPC2 (Intel Atom-based computer).
 
  From the device ID you give, it's definitely OXPCIe952 based.
 
 
 >After applying the puc patch, enabling puc in the kernel and re-compiling,
 >the card is recognized, but no driver was assigned.
 >
 >I ran a pciconf -lv to list the pci devices and found the chip id's didn't
 >match anything in the patched driver.
 
 Correct; the current version of the patch only attempts to support the 
 OXPCIe952 when it's configured as two serial ports.
 
 
 >So, I changed an entry in the patched code for the 952 chip from "0x1415,
 >0x15d"   to "0x1415, 0xc11b" so that it matched the output from the pciconf.
 >Since I was only interested in the serial function, I didn't try to patch
 >for the parallel port function.    After recompiling the kernel it worked
 >and assigned a device driver to the UART.
 
 Great! I suspect that you'd rather the card used the OXPCIe952 to offer 
 two serial ports rather than one serial and one parallel port. At the 
 moment, mini PCI Express cards are not that common and I couldn't find 
 one that had two serial ports.
 
 
 >I wasn't comfortable in my patch to add a new table entry, so that is why I
 >changed an existing entry.   I suspect the proper patch would be to add a
 >new table entry.     I've included the output from my "pciconf" that shows
 >the pci card and chip ids for both the serial and parallel ports.   Notice
 >that it assigned a device puc0 to the UART.
 
 The OXPCIe952 can be used in many different configurations. The patch as 
 it currently stands only supports the '2 native UARTs' function of the 
 OXPCIe952, but on re-reading the data sheet, I realise that the patch 
 should also support the '1 native UART' function that your card is 
 offering.
 
 
 I'll check the hex arithmetic again before updating the patch, but I 
 believe that the relevant entries for '1 native UART' are:
 
 0x1415, 0xc11b (function 3)
 0x1415, 0xc11f (function 3)
 0x1415, 0xc138 (function 0)
 0x1415, 0xc13d (function 1)
 
 This means that there's actually four table entries to add.
 
 
 My patch doesn't attempt to add support OXPCIe952 legacy UARTs or 
 parallel ports; I don't have any suitable hardware to test with.
 
 
 
 >none3 at pci0:3:0:0:       class=0x070102 card=0xc1181415 chip=0xc1181415
 >rev=0x00 hdr=0x00
 >
 >    vendor     = 'Oxford Semiconductor Ltd'
 >
 >    class      = simple comms
 >
 >    subclass   = parallel port
 >
 >puc0 at pci0:3:0:3:        class=0x070002 card=0xc11b1415 chip=0xc11b1415
 >rev=0x00 hdr=0x00
 >
 >    vendor     = 'Oxford Semiconductor Ltd'
 >
 >    class      = simple comms
 >
 >    subclass   = UART
 
 
 That looks correct - there's no support for the parallel port, though it 
 shouldn't be that hard to add.
 
 OXPCIe952 legacy UARTs and parallel ports should be much more 
 straightforward than the native UARTs that the current patch supports. 
 They may just need table entries, though I haven't checked too 
 carefully. It's hard to write drivers for hardware that you don't have.
 
 
 Most importantly, does the serial port work with your amended patch?
 
 Does /var/run/dmesg.boot contain a line:
 puc0: 1 UARTs detected
 
 
 >I'm very new to FreeBSD and am not sure if I approached notification of my
 >findings in the correct way by submitting this followup.
 
 You did the right thing by replying to me and cc'ing 
 bug-followup at FreeBSD.org
 
 The only suggestion I have is to send plain text emails; GNATS makes a 
 bit of a mess of HTML as you can see at
 http://www.freebsd.org/cgi/query-pr.cgi?pr=134878
 
 
 >In any case, I
 >hope it is helpful since I assume it is hard for the developers to test on
 >every combination of computer and card.
 
 Indeed. My main aim was to support my OXPCIe954 based card, but I wanted 
 to support other cards in the family where possible.
 
 
 >If a new patch is released, I'd be happy to test it out.
 
 I'll attempt to update the patch some time this week to cover the '1 
 native UART' functions on the OXPCIe952, which will mean the patch 
 supports your serial port.
 
 I may also have a go at the parallel port and legacy UART functions. 
 Could you test the parallel port if I attempt to support it, or have you 
 not got any parallel devices? I suspect that most people have left 
 parallel port devices behind by now - printers have used USB for many 
 years.
 
 
 I'm also planning to revisit the patch to attempt to add support for 
 MSI-X on these Oxford UARTs, though that requires changing some of the 
 main puc code, not just pucdata.c. I want to use my OXPCIe954 based card 
 for NTP master clocks - using MSI-X offers the prospect of reducing 
 interrupt latency and jitter. It's just a matter of finding the 
 necessary time.
 
 
 
 Best wishes,
 
 
 
 
 David
 -- 
 David Wood
 david at wood2.org.uk