linux/drivers/pci/pcie/rcec.c
Qiuxu Zhuo d9b7eae8e3 PCI/RCEC: Fix RCiEP device to RCEC association
rcec_assoc_rciep() used "rciep->devfn" (a single byte encoding both the
device and function number) as the device number to check whether the
corresponding bit was set in the RCEC's Association Bitmap for RCiEPs.

But per PCIe r5.0, sec 7.9.10.2, "Association Bitmap for RCiEPs", the
32-bit bitmap contains one bit per device.  That bit applies to all
functions of the device.

Fix rcec_assoc_rciep() to convert the value of "rciep->devfn" to a device
number to ensure that RCiEP devices are correctly associated with the RCEC.

Reported-and-tested-by: Wen Jin <wen.jin@intel.com>
Fixes: 507b460f81 ("PCI/ERR: Add pcie_link_rcec() to associate RCiEPs")
Link: https://lore.kernel.org/r/20210222011717.43266-1-qiuxu.zhuo@intel.com
Signed-off-by: Qiuxu Zhuo <qiuxu.zhuo@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Sean V Kelley <sean.v.kelley@intel.com>
2021-03-10 15:10:46 -06:00

191 lines
4.4 KiB
C

// 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 == 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;
}