From: Sean V Kelley <sean.v.kelley@intel.com>
Date: Fri, 20 Nov 2020 16:10:24 -0800
Subject: PCI/ERR: Cache RCEC EA Capability offset in pci_init_capabilities()
Git-commit: 90655631988f8f501529e6de5f13614389717ead
Patch-mainline: 5.11-rc1
References: jsc#SLE-13736 jsc#SLE-14845

Extend support for Root Complex Event Collectors by decoding and caching
the RCEC Endpoint Association Extended Capabilities when enumerating. Use
that cached information for later error source reporting. See PCIe r5.0,
sec 7.9.10.

Co-developed-by: Qiuxu Zhuo <qiuxu.zhuo@intel.com>
Link: https://lore.kernel.org/r/20201121001036.8560-4-sean.v.kelley@intel.com
Tested-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> # non-native/no RCEC
Signed-off-by: Qiuxu Zhuo <qiuxu.zhuo@intel.com>
Signed-off-by: Sean V Kelley <sean.v.kelley@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
 drivers/pci/pci.h         |   17 +++++++++++++
 drivers/pci/pcie/Makefile |    2 -
 drivers/pci/pcie/rcec.c   |   59 ++++++++++++++++++++++++++++++++++++++++++++++
 drivers/pci/probe.c       |    3 ++
 include/linux/pci.h       |    4 +++
 5 files changed, 84 insertions(+), 1 deletion(-)
 create mode 100644 drivers/pci/pcie/rcec.c

--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -412,6 +412,15 @@ int aer_get_device_error_info(struct pci
 void aer_print_error(struct pci_dev *dev, struct aer_err_info *info);
 #endif	/* CONFIG_PCIEAER */
 
+#ifdef CONFIG_PCIEPORTBUS
+/* Cached RCEC Endpoint Association */
+struct rcec_ea {
+	u8		nextbusn;
+	u8		lastbusn;
+	u32		bitmap;
+};
+#endif
+
 #ifdef CONFIG_PCIE_DPC
 void pci_save_dpc_state(struct pci_dev *dev);
 void pci_restore_dpc_state(struct pci_dev *dev);
@@ -424,6 +433,14 @@ static inline void pci_restore_dpc_state
 static inline void pci_dpc_init(struct pci_dev *pdev) {}
 #endif
 
+#ifdef CONFIG_PCIEPORTBUS
+void pci_rcec_init(struct pci_dev *dev);
+void pci_rcec_exit(struct pci_dev *dev);
+#else
+static inline void pci_rcec_init(struct pci_dev *dev) {}
+static inline void pci_rcec_exit(struct pci_dev *dev) {}
+#endif
+
 #ifdef CONFIG_PCI_ATS
 void pci_restore_ats_state(struct pci_dev *dev);
 #else
--- a/drivers/pci/pcie/Makefile
+++ b/drivers/pci/pcie/Makefile
@@ -2,7 +2,7 @@
 #
 # Makefile for PCI Express features and port driver
 
-pcieportdrv-y			:= portdrv_core.o portdrv_pci.o err.o
+pcieportdrv-y			:= portdrv_core.o portdrv_pci.o err.o rcec.o
 
 obj-$(CONFIG_PCIEPORTBUS)	+= pcieportdrv.o
 
--- /dev/null
+++ b/drivers/pci/pcie/rcec.c
@@ -0,0 +1,59 @@
+// 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"
+
+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;
+}
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -2163,6 +2163,7 @@ static void pci_configure_device(struct
 static void pci_release_capabilities(struct pci_dev *dev)
 {
 	pci_aer_exit(dev);
+	pci_rcec_exit(dev);
 	pci_vpd_release(dev);
 	pci_iov_release(dev);
 	pci_free_cap_save_buffers(dev);
@@ -2379,6 +2380,8 @@ static void pci_init_capabilities(struct
 	/* Downstream Port Containment */
 	pci_dpc_init(dev);
 
+	pci_rcec_init(dev);		/* Root Complex Event Collector */
+
 	pcie_report_downtraining(dev);
 
 	if (pci_probe_reset_function(dev) == 0)
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -291,6 +291,7 @@ struct pci_vpd;
 struct pci_sriov;
 struct pci_ats;
 struct pci_p2pdma;
+struct rcec_ea;
 
 /* The pci_dev structure describes PCI devices */
 struct pci_dev {
@@ -314,6 +315,9 @@ struct pci_dev {
 	u16		aer_cap;	/* AER capability offset */
 	struct aer_stats *aer_stats;	/* AER stats for this device */
 #endif
+#ifdef CONFIG_PCIEPORTBUS
+	struct rcec_ea	*rcec_ea;	/* RCEC cached endpoint association */
+#endif
 	u8		pcie_cap;	/* PCIe capability offset */
 	u8		msi_cap;	/* MSI capability offset */
 	u8		msix_cap;	/* MSI-X capability offset */