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- // SPDX-License-Identifier: GPL-2.0
- /*
- * Root Complex Event Collector Support
- *
- * Authors:
- * Sean V Kelley <[email protected]>
- * Qiuxu Zhuo <[email protected]>
- *
- * Copyright (C) 2020 Intel Corp.
- */
- #include <linux/kernel.h>
- #include <linux/pci.h>
- #include <linux/pci_regs.h>
- #include "../pci.h"
- struct walk_rcec_data {
- struct pci_dev *rcec;
- int (*user_callback)(struct pci_dev *dev, void *data);
- void *user_data;
- };
- static bool rcec_assoc_rciep(struct pci_dev *rcec, struct pci_dev *rciep)
- {
- unsigned long bitmap = rcec->rcec_ea->bitmap;
- unsigned int devn;
- /* An RCiEP found on a different bus in range */
- if (rcec->bus->number != rciep->bus->number)
- return true;
- /* Same bus, so check bitmap */
- for_each_set_bit(devn, &bitmap, 32)
- if (devn == PCI_SLOT(rciep->devfn))
- return true;
- return false;
- }
- static int link_rcec_helper(struct pci_dev *dev, void *data)
- {
- struct walk_rcec_data *rcec_data = data;
- struct pci_dev *rcec = rcec_data->rcec;
- if ((pci_pcie_type(dev) == PCI_EXP_TYPE_RC_END) &&
- rcec_assoc_rciep(rcec, dev)) {
- dev->rcec = rcec;
- pci_dbg(dev, "PME & error events signaled via %s\n",
- pci_name(rcec));
- }
- return 0;
- }
- static int walk_rcec_helper(struct pci_dev *dev, void *data)
- {
- struct walk_rcec_data *rcec_data = data;
- struct pci_dev *rcec = rcec_data->rcec;
- if ((pci_pcie_type(dev) == PCI_EXP_TYPE_RC_END) &&
- rcec_assoc_rciep(rcec, dev))
- rcec_data->user_callback(dev, rcec_data->user_data);
- return 0;
- }
- static void walk_rcec(int (*cb)(struct pci_dev *dev, void *data),
- void *userdata)
- {
- struct walk_rcec_data *rcec_data = userdata;
- struct pci_dev *rcec = rcec_data->rcec;
- u8 nextbusn, lastbusn;
- struct pci_bus *bus;
- unsigned int bnr;
- if (!rcec->rcec_ea)
- return;
- /* Walk own bus for bitmap based association */
- pci_walk_bus(rcec->bus, cb, rcec_data);
- nextbusn = rcec->rcec_ea->nextbusn;
- lastbusn = rcec->rcec_ea->lastbusn;
- /* All RCiEP devices are on the same bus as the RCEC */
- if (nextbusn == 0xff && lastbusn == 0x00)
- return;
- for (bnr = nextbusn; bnr <= lastbusn; bnr++) {
- /* No association indicated (PCIe 5.0-1, 7.9.10.3) */
- if (bnr == rcec->bus->number)
- continue;
- bus = pci_find_bus(pci_domain_nr(rcec->bus), bnr);
- if (!bus)
- continue;
- /* Find RCiEP devices on the given bus ranges */
- pci_walk_bus(bus, cb, rcec_data);
- }
- }
- /**
- * pcie_link_rcec - Link RCiEP devices associated with RCEC.
- * @rcec: RCEC whose RCiEP devices should be linked.
- *
- * Link the given RCEC to each RCiEP device found.
- */
- void pcie_link_rcec(struct pci_dev *rcec)
- {
- struct walk_rcec_data rcec_data;
- if (!rcec->rcec_ea)
- return;
- rcec_data.rcec = rcec;
- rcec_data.user_callback = NULL;
- rcec_data.user_data = NULL;
- walk_rcec(link_rcec_helper, &rcec_data);
- }
- /**
- * pcie_walk_rcec - Walk RCiEP devices associating with RCEC and call callback.
- * @rcec: RCEC whose RCiEP devices should be walked
- * @cb: Callback to be called for each RCiEP device found
- * @userdata: Arbitrary pointer to be passed to callback
- *
- * Walk the given RCEC. Call the callback on each RCiEP found.
- *
- * If @cb returns anything other than 0, break out.
- */
- void pcie_walk_rcec(struct pci_dev *rcec, int (*cb)(struct pci_dev *, void *),
- void *userdata)
- {
- struct walk_rcec_data rcec_data;
- if (!rcec->rcec_ea)
- return;
- rcec_data.rcec = rcec;
- rcec_data.user_callback = cb;
- rcec_data.user_data = userdata;
- walk_rcec(walk_rcec_helper, &rcec_data);
- }
- void pci_rcec_init(struct pci_dev *dev)
- {
- struct rcec_ea *rcec_ea;
- u32 rcec, hdr, busn;
- u8 ver;
- /* Only for Root Complex Event Collectors */
- if (pci_pcie_type(dev) != PCI_EXP_TYPE_RC_EC)
- return;
- rcec = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_RCEC);
- if (!rcec)
- return;
- rcec_ea = kzalloc(sizeof(*rcec_ea), GFP_KERNEL);
- if (!rcec_ea)
- return;
- pci_read_config_dword(dev, rcec + PCI_RCEC_RCIEP_BITMAP,
- &rcec_ea->bitmap);
- /* Check whether RCEC BUSN register is present */
- pci_read_config_dword(dev, rcec, &hdr);
- ver = PCI_EXT_CAP_VER(hdr);
- if (ver >= PCI_RCEC_BUSN_REG_VER) {
- pci_read_config_dword(dev, rcec + PCI_RCEC_BUSN, &busn);
- rcec_ea->nextbusn = PCI_RCEC_BUSN_NEXT(busn);
- rcec_ea->lastbusn = PCI_RCEC_BUSN_LAST(busn);
- } else {
- /* Avoid later ver check by setting nextbusn */
- rcec_ea->nextbusn = 0xff;
- rcec_ea->lastbusn = 0x00;
- }
- dev->rcec_ea = rcec_ea;
- }
- void pci_rcec_exit(struct pci_dev *dev)
- {
- kfree(dev->rcec_ea);
- dev->rcec_ea = NULL;
- }
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