On Tue, Mar 29, 2022 at 01:43:21PM +0300, Shlomo Pongratz wrote:
> On commit 7b94b53db34f ("PCI/P2PDMA: Add Intel Sky Lake-E Root Ports B, C, D to the whitelist")
'in commit' and it is expected to word wrap the description
> Andrew Maier added the Sky Lake-E additional devices
> 2031, 2032 and 2033 root ports to the already existing 2030 device.
>
> The Intel devices 2030, 2031, 2032 and 2033 which are ports A, B, C and D,
> and if all exist they will occupy slots 0 till 3 in that order.
>
> Now if for example device 2030 is missing then there will no device on slot 0, but
> other devices can reside on other slots according to there port.
> For this reason the test that insisted that the bridge should be on slot 0 was modified
> to support bridges that are not on slot 0.
This needs updating to the new test
>
> Signed-off-by: Shlomo Pongratz <shlomop@xxxxxxxxxx>
> drivers/pci/p2pdma.c | 42 +++++++++++++++++++++++++++++++++++++-----
> 1 file changed, 37 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c
> index 30b1df3c9d2f..c088d4ab64f4 100644
> +++ b/drivers/pci/p2pdma.c
> @@ -307,6 +307,7 @@ static const struct pci_p2pdma_whitelist_entry {
> unsigned short device;
> enum {
> REQ_SAME_HOST_BRIDGE = 1 << 0,
> + IS_ROOT_PORT = 1 << 1,
> } flags;
> } pci_p2pdma_whitelist[] = {
> /* Intel Xeon E5/Core i7 */
> @@ -316,15 +317,38 @@ static const struct pci_p2pdma_whitelist_entry {
> {PCI_VENDOR_ID_INTEL, 0x2f00, REQ_SAME_HOST_BRIDGE},
> {PCI_VENDOR_ID_INTEL, 0x2f01, REQ_SAME_HOST_BRIDGE},
> /* Intel SkyLake-E */
> - {PCI_VENDOR_ID_INTEL, 0x2030, 0},
> - {PCI_VENDOR_ID_INTEL, 0x2031, 0},
> - {PCI_VENDOR_ID_INTEL, 0x2032, 0},
> - {PCI_VENDOR_ID_INTEL, 0x2033, 0},
> + {PCI_VENDOR_ID_INTEL, 0x2030, IS_ROOT_PORT},
> + {PCI_VENDOR_ID_INTEL, 0x2031, IS_ROOT_PORT},
> + {PCI_VENDOR_ID_INTEL, 0x2032, IS_ROOT_PORT},
> + {PCI_VENDOR_ID_INTEL, 0x2033, IS_ROOT_PORT},
> {PCI_VENDOR_ID_INTEL, 0x2020, 0},
> {PCI_VENDOR_ID_INTEL, 0x09a2, 0},
> {}
> };
>
> +/*
> + * The functionality of thisunction can be integrated into
> + * __host_bridge_whitelist function but this will make the code
> + * less readable
This comment is not useful, explain what the function does or delete
it
> + */
> +static bool pci_is_root_port(struct pci_dev *root)
> +{
> + const struct pci_p2pdma_whitelist_entry *entry;
> + unsigned short vendor, device;
> +
> + vendor = root->vendor;
> + device = root->device;
> +
> + for (entry = pci_p2pdma_whitelist; entry->vendor; entry++) {
> + if (vendor != entry->vendor || device != entry->device)
> + continue;
> +
> + if (entry->flags & IS_ROOT_PORT)
> + return true;
> + }
> + return false;
> +}
> +
> /*
> * This lookup function tries to find the PCI device corresponding to a given
> * host bridge.
> @@ -333,6 +357,11 @@ static const struct pci_p2pdma_whitelist_entry {
> * bus->devices list and that the devfn is 00.0. These assumptions should hold
> * for all the devices in the whitelist above.
> *
> + * The method above will work in most cases but not for all.
> + * Note that the Intel devices 2030, 2031, 2032 and 2033 are ports A, B, C and D.
> + * Consider on a bus X only port C has devices connected to it so in the PCI scan only
> + * device 8086:2032 on 0000:X:02.0 will be found as bridges with no children are ignored
> + *
> * This function is equivalent to pci_get_slot(host->bus, 0), however it does
> * not take the pci_bus_sem lock seeing __host_bridge_whitelist() must not
> * sleep.
> @@ -350,7 +379,9 @@ static struct pci_dev *pci_host_bridge_dev(struct pci_host_bridge *host)
>
> if (!root)
> return NULL;
> - if (root->devfn != PCI_DEVFN(0, 0))
> +
> + /* Intel Sky Lake-E host root ports can be on no zero slot */
> + if (root->devfn != PCI_DEVFN(0, 0) && !pci_is_root_port(root))
> return NULL;
The name pci_host_bridge_dev needs some attention if it is now
returning a root port.
> @@ -372,6 +403,7 @@ static bool __host_bridge_whitelist(struct pci_host_bridge *host,
> for (entry = pci_p2pdma_whitelist; entry->vendor; entry++) {
> if (vendor != entry->vendor || device != entry->device)
> continue;
> +
> if (entry->flags & REQ_SAME_HOST_BRIDGE && !same_host_bridge)
> return false;
Unnecessary hunk
Jason
