On Tuesday, January 25, 2011 9:47:35 am Philip Soeberg wrote:
> Hi,
>
> I'm in a particular problem where I need to set my custom pcie adapter
> into d3hot power-mode and a couple of seconds later reset it back to d0.
> The board has an FPGA directly attached to the pcie interface, and as I
> need to re-configure the FPGA on the fly, I have to ensure the datalink
> layer between the upstream bridge and my device is idle to prevent any
> hickups.
>
> On linux I simply do a pci_save_state(device) followed by
> pci_set_power_state(device, d3hot), then after my magic on my board, I
> do the reverse: pci_set_power_state(device, d0) followed by
> pci_restore_state(device).
>
> On FreeBSD, say 8, I've found the pci_set_powerstate function, which is
> documented in PCI(9), but that function does not save nor restore the
> config space.
>
> I've tried, just for the fun of it, to go via pci_cfg_save(device,
> dinfo, 0) with dinfo being device_get_ivars(device) and then
> subsequently restoring the config space back via pci_cfg_restore(), but
> since both those functions are declared in <dev/pci/pci_private.h> I'm
> not sure if I'm supposed to use those directly or not.. Besides, I'm not
> really having any luck with that approach.
>
> Reading high and low on the net suggest that not all too many driver
> devs are concerned with suspend/resume operation of their device, and if
> they are, leave it to user-space to decide when to suspend/resume a
> device.. I would like to be able to save off my device' config space,
> put it to sleep (d3hot), wake it back up (d0) and restore the device'
> config space directly from the device' own driver..
>
> Anyone who can help me with this?
Use this:
pci_cfg_save(dev, dinfo, 0);
pci_set_powerstate(dev, PCI_POWERSTATE_D3);
/* do stuff */
/* Will set state to D0. */
pci_cfg_restore(dev, dinfo);
We probably should create some wrapper routines (pci_save_state() and
pci_restore_state() would be fine) that hide the 'dinfo' detail as that isn't
something device drivers should have to know.
--
John Baldwin
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