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// SPDX-License-Identifier: GPL-2.0
/*
* Root Complex Event Collector Support
*
* Authors:
* Sean V Kelley <sean.v.kelley@intel.com>
* Qiuxu Zhuo <qiuxu.zhuo@intel.com>
*
* 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 == 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 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);
}
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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