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Set PCIe device's Max_Payload_Size to match PCIe root's.

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Usually on boot the MPS is already configured by BIOS.  But we've
found that on hot-plug it is not true at least for our Supermicro
X11 boards.  As result, mismatch between root's configuration of
256 bytes and device's default of 128 bytes cause problems for some
devices, while others seem to work fine.

MFC after:	1 month
Sponsored by:	iXsystems, Inc.
This commit is contained in:
Alexander Motin 2021-04-05 10:34:40 -04:00
parent b8639a1098
commit 5a898b2b78
1 changed files with 40 additions and 0 deletions
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40
sys/dev/pci/pci.c
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@ -4267,6 +4267,45 @@ pci_create_iov_child_method(device_t bus, device_t pf, uint16_t rid,
}
#endif
/*
* For PCIe device set Max_Payload_Size to match PCIe root's.
*/
static void
pcie_setup_mps(device_t dev)
{
struct pci_devinfo *dinfo = device_get_ivars(dev);
device_t root;
uint16_t rmps, mmps, mps;
if (dinfo->cfg.pcie.pcie_location == 0)
return;
root = pci_find_pcie_root_port(dev);
if (root == NULL)
return;
/* Check whether the MPS is already configured. */
rmps = pcie_read_config(root, PCIER_DEVICE_CTL, 2) &
PCIEM_CTL_MAX_PAYLOAD;
mps = pcie_read_config(dev, PCIER_DEVICE_CTL, 2) &
PCIEM_CTL_MAX_PAYLOAD;
if (mps == rmps)
return;
/* Check whether the device is capable of the root's MPS. */
mmps = (pcie_read_config(dev, PCIER_DEVICE_CAP, 2) &
PCIEM_CAP_MAX_PAYLOAD) << 5;
if (rmps > mmps) {
/*
* The device is unable to handle root's MPS. Limit root.
* XXX: We should traverse through all the tree, applying
* it to all the devices.
*/
pcie_adjust_config(root, PCIER_DEVICE_CTL,
PCIEM_CTL_MAX_PAYLOAD, mmps, 2);
} else {
pcie_adjust_config(dev, PCIER_DEVICE_CTL,
PCIEM_CTL_MAX_PAYLOAD, rmps, 2);
}
}
static void
pci_add_child_clear_aer(device_t dev, struct pci_devinfo *dinfo)
{
@ -4354,6 +4393,7 @@ pci_add_child(device_t bus, struct pci_devinfo *dinfo)
pci_cfg_restore(dev, dinfo);
pci_print_verbose(dinfo);
pci_add_resources(bus, dev, 0, 0);
pcie_setup_mps(dev);
pci_child_added(dinfo->cfg.dev);
if (pci_clear_aer_on_attach)