Re: PCIe can not rescan for new PCIe device ( FPGA board )

From: Abdelghani Ouchabane
Date: Fri Oct 07 2011 - 12:23:03 EST


Bjorn Helgaas wrote:
[added cc: linux-pci@xxxxxxxxxxxxxxx]

On Fri, Oct 7, 2011 at 1:16 AM, Abdelghani Ouchabane
<abdelghani@xxxxxxxxx> wrote:
Hallo,

We are developing a FPGA board connected to a Fedora 15 PC host over PCIe.
Right now, in the implementation and debug phase, I often need to power off
and
power on the device or try different boards. This causes a problem with the
Fedora 15 running on the AMD PC.

Typically the PC is booted when I need to insert the device under test. As
expected, the Linux doesn't find the device and the software app cannot talk
to it.

* If I do "lspci -v" then it does not list our device.

Do you have pciehp enabled and loaded? I would think a PCIe hot-add
should automatically rescan the bus. Does dmesg say anything when you
do the hot-add?
Thanks Bjorn,

Yes, I have them :

****************************************************************************************************
lsmod :

pciehp 20282 0
cgosdrv 17632 0
****************************************************************************************************
/etc/modprobe.d/pciehp.conf
alias pci:v00001234d00000002sv00001234sd00000001bc11sc80i00 pciehp
options pciehp pciehp_force=1 pciehp_debug=1
****************************************************************************************************

After I plug my board in, I executed echo 1 > /sys/bus/pci/rescan

dmesg:

[ 73.203895] pci 0000:02:00.0: [1234:0002] type 0 class 0x001180
[ 73.203895] pci 0000:02:00.0: reg 10: [mem 0x00000000-0x00000fff 64bit pref]
[ 73.204083] pci 0000:02:00.0: reg 18: [mem 0x00000000-0x0003ffff 64bit pref]
[ 73.204114] pci 0000:02:00.0: reg 20: [mem 0x00000000-0x00000fff 64bit pref]
[ 73.206190] pci 0000:00:01.0: BAR 6: [??? 0x00000000 flags 0x2] has bogus alignment
[ 73.206215] pci 0000:02:00.0: BAR 2: assigned [mem 0x40200000-0x4023ffff 64bit pref]
[ 73.206236] pci 0000:02:00.0: BAR 2: set to [mem 0x40200000-0x4023ffff 64bit pref] (PCI address [0x40200000-0x4023ffff])
[ 73.206247] pci 0000:02:00.0: BAR 0: assigned [mem 0x40240000-0x40240fff 64bit pref]
[ 73.206266] pci 0000:02:00.0: BAR 0: set to [mem 0x40240000-0x40240fff 64bit pref] (PCI address [0x40240000-0x40240fff])
[ 73.206277] pci 0000:02:00.0: BAR 4: assigned [mem 0x40241000-0x40241fff 64bit pref]
[ 73.206295] pci 0000:02:00.0: BAR 4: set to [mem 0x40241000-0x40241fff 64bit pref] (PCI address [0x40241000-0x40241fff])

****************************************************************************************************
* Then I execute "echo 1 > /sys/bus/pci/rescan"

* Now "lspci -v" lists our device.

That means config space accesses to your device seem to work fine.

* But our software returns : 0xFFFFFFFF

Your device is on bus 02. Did you confirm that there are host bridge
and P2P bridge apertures containing the BARs, e.g,. the [mem
0x40241000-0x40241fff] region? The dmesg log should show all this
information.
Yes, it is on the bus 02.

Here is the log of dmesg :

[ 69.806322] pci 0000:02:00.0: [1234:0002] type 0 class 0x001180
[ 69.806426] pci 0000:02:00.0: reg 10: [mem 0x00000000-0x00000fff 64bit pref]
[ 69.806506] pci 0000:02:00.0: reg 18: [mem 0x00000000-0x0003ffff 64bit pref]
[ 69.806585] pci 0000:02:00.0: reg 20: [mem 0x00000000-0x00000fff 64bit pref]
[ 69.808194] pci 0000:00:01.0: BAR 6: [??? 0x00000000 flags 0x2] has bogus alignment
[ 69.808271] pci 0000:02:00.0: BAR 2: assigned [mem 0x40200000-0x4023ffff 64bit pref]
[ 69.808343] pci 0000:02:00.0: BAR 2: set to [mem 0x40200000-0x4023ffff 64bit pref] (PCI address [0x40200000-0x4023ffff])
[ 69.808412] pci 0000:02:00.0: BAR 0: assigned [mem 0x40240000-0x40240fff 64bit pref]
[ 69.808650] pci 0000:02:00.0: BAR 0: set to [mem 0x40240000-0x40240fff 64bit pref] (PCI address [0x40240000-0x40240fff])
[ 69.808888] pci 0000:02:00.0: BAR 4: assigned [mem 0x40241000-0x40241fff 64bit pref]
[ 69.810805] pci 0000:02:00.0: BAR 4: set to [mem 0x40241000-0x40241fff 64bit pref] (PCI address [0x40241000-0x40241fff])
[ 84.309870] pci 0000:02:00.0: enabling device (0000 -> 0002)
[ 84.310082] pci 0000:02:00.0: PCI INT A -> Link[LNKB] -> GSI 7 (level, low) -> IRQ 7
[ 85.581946] pci 0000:02:00.0: [1234:0002] type 0 class 0x001180
[ 85.582300] pci 0000:02:00.0: reg 10: [mem 0x40240000-0x40240fff 64bit pref]
[ 85.582467] pci 0000:02:00.0: reg 18: [mem 0x40200000-0x4023ffff 64bit pref]
[ 85.582631] pci 0000:02:00.0: reg 20: [mem 0x40241000-0x40241fff 64bit pref]
[ 85.584195] pci 0000:00:01.0: BAR 6: [??? 0x00000000 flags 0x2] has bogus alignment
[ 85.584442] pci 0000:02:00.0: BAR 2: assigned [mem 0x40200000-0x4023ffff 64bit pref]
[ 85.584682] pci 0000:02:00.0: BAR 2: set to [mem 0x40200000-0x4023ffff 64bit pref] (PCI address [0x40200000-0x4023ffff])
[ 85.584921] pci 0000:02:00.0: BAR 0: assigned [mem 0x40240000-0x40240fff 64bit pref]
[ 85.585346] pci 0000:02:00.0: BAR 0: set to [mem 0x40240000-0x40240fff 64bit pref] (PCI address [0x40240000-0x40240fff])
[ 85.585587] pci 0000:02:00.0: BAR 4: assigned [mem 0x40241000-0x40241fff 64bit pref]
[ 85.585826] pci 0000:02:00.0: BAR 4: set to [mem 0x40241000-0x40241fff 64bit pref] (PCI address [0x40241000-0x40241fff])
[ 86.915177] pci 0000:02:00.0: PCI INT A -> Link[LNKB] -> GSI 7 (level, low) -> IRQ 7

****************************************************************************************************

Many thanks in advance.

Cheers,
Ghani
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