PCI/ERR: Cache RCEC EA Capability offset in pci_init_capabilities()

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>

4 files changed, 79 insertions, 1 deletions

diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index f86cae9aa1f4..12dcad8f3635 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -448,6 +448,15 @@ int aer_get_device_error_info(struct pci_dev *dev, struct aer_err_info *info);
 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);
@@ -460,6 +469,14 @@ static inline void pci_restore_dpc_state(struct pci_dev *dev) {}
 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
 /* Address Translation Service */
 void pci_ats_init(struct pci_dev *dev);
diff --git a/drivers/pci/pcie/Makefile b/drivers/pci/pcie/Makefile
index 68da9280ff11..d9697892fa3e 100644
--- 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
 
diff --git a/drivers/pci/pcie/rcec.c b/drivers/pci/pcie/rcec.c
new file mode 100644
index 000000000000..038e9d706d5f
--- /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;
+}
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 4289030b0fff..f22e1451d65d 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -2216,6 +2216,7 @@ static void pci_configure_device(struct pci_dev *dev)
 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);
@@ -2415,6 +2416,7 @@ static void pci_init_capabilities(struct pci_dev *dev)
 	pci_ptm_init(dev);		/* Precision Time Measurement */
 	pci_aer_init(dev);		/* Advanced Error Reporting */
 	pci_dpc_init(dev);		/* Downstream Port Containment */
+	pci_rcec_init(dev);		/* Root Complex Event Collector */
 
 	pcie_report_downtraining(dev);