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path: root/drivers/pci/pcie/rcec.c
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Diffstat (limited to 'drivers/pci/pcie/rcec.c')
-rw-r--r--drivers/pci/pcie/rcec.c190
1 files changed, 190 insertions, 0 deletions
diff --git a/drivers/pci/pcie/rcec.c b/drivers/pci/pcie/rcec.c
new file mode 100644
index 000000000..d0bcd141a
--- /dev/null
+++ b/drivers/pci/pcie/rcec.c
@@ -0,0 +1,190 @@
+// 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;
+}