> On Thu, Jun 27, 2024 at 12:58:56AM +0000, Zhou Shengqing wrote:
> > This patch add 1k granularity for intel root port bridge.Intel latest
> > server CPU support 1K granularity,And there is an BIOS setup item named
> > "EN1K",but linux doesn't support it. if an IIO has 5 IOU (SPR has 5 IOUs)
> > all are bifurcated 2x8.In a 2P server system,There are 20 P2P bridges
> > present.if keep 4K granularity allocation,it need 20*4=80k io space,
> > exceeding 64k.I test it in a 16*nvidia 4090s system under intel eaglestrem
> > platform.There are six 4090s that cannot be allocated I/O resources.
> > So I applied this patch.And I found a similar implementation in quirks.c,
> > but it only targets the Intel P64H2 platform.
> >
> > Signed-off-by: Zhou Shengqing <zhoushengqing@xxxxxxxxxxx>
> > ---
> > drivers/pci/probe.c | 23 +++++++++++++++++++++++
> > 1 file changed, 23 insertions(+)
> >
> > diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
> > index 5fbabb4e3425..909962795311 100644
> > --- a/drivers/pci/probe.c
> > +++ b/drivers/pci/probe.c
> > @@ -461,6 +461,9 @@ static void pci_read_bridge_windows(struct pci_dev *bridge)
> > u32 buses;
> > u16 io;
> > u32 pmem, tmp;
> > + u16 ven_id, dev_id;
> > + u16 en1k = 0;
> > + struct pci_dev *dev = NULL;
> > struct resource res;
> >
> > pci_read_config_dword(bridge, PCI_PRIMARY_BUS, &buses);
> > @@ -478,6 +481,26 @@ static void pci_read_bridge_windows(struct pci_dev *bridge)
> > }
> > if (io) {
> > bridge->io_window = 1;
> > + if (pci_is_root_bus(bridge->bus)) {
> > + list_for_each_entry(dev, &bridge->bus->devices, bus_list) {
> > + pci_read_config_word(dev, PCI_VENDOR_ID, &ven_id);
> > + pci_read_config_word(dev, PCI_DEVICE_ID, &dev_id);
> > + if (ven_id == PCI_VENDOR_ID_INTEL && dev_id == 0x09a2) {
> > + /*IIO MISC Control offset 0x1c0*/
> > + pci_read_config_word(dev, 0x1c0, &en1k);
> > + }
> > + }
> > + /*
> > + *Intel ICX SPR EMR GNR
> > + *IIO MISC Control (IIOMISCCTRL_1_5_0_CFG) — Offset 1C0h
> > + *bit 2:Enable 1K (EN1K)
> > + *This bit when set, enables 1K granularity for I/O space decode
> > + *in each of the virtual P2P bridges
> > + *corresponding to root ports, and DMI ports.
> > + */
> > + if (en1k & 0x4)
> > + bridge->io_window_1k = 1;
> > + }
>
> I still think this is not going to work because I don't want this kind
> of device-specific clutter in this generic path. The pcibios_*
> interfaces are history that we'd like to get rid of also, but it would
> be better than putting it here.
Do you think it should be putted to the pci_bios* interface?
And if there is no suitable place to apply this patch,
then let's just ignore this issue.
>
> Please follow english conventions as much as you can, e.g., space
> after "*" in comments, space after period at end of sentence,
> capitalize first word of sentence, blank line between paragraphs.
> Most of this you can see by looking at other comments.
>
Thank you sincerely for your help with my first patch commitment.
> > pci_read_bridge_io(bridge, &res, true);
> > }
> >
> > --
> > 2.39.2
> >
