PCI/ERR: Bind RCEC devices to the Root Port driver

If a Root Complex Integrated Endpoint (RCiEP) is implemented, it may signal
errors through a Root Complex Event Collector (RCEC).  Each RCiEP must be
associated with no more than one RCEC.

For an RCEC (which is technically not a Bridge), error messages "received"
from associated RCiEPs must be enabled for "transmission" in order to cause
a System Error via the Root Control register or (when the Advanced Error
Reporting Capability is present) reporting via the Root Error Command
register and logging in the Root Error Status register and Error Source
Identification register.

Given the commonality with Root Ports and the need to also support AER and
PME services for RCECs, extend the Root Port driver to support RCEC devices
by adding the RCEC Class ID to the driver structure.
Co-developed-by: Sean V Kelley <sean.v.kelley@intel.com>
Link: https://lore.kernel.org/r/20201121001036.8560-3-sean.v.kelley@intel.com
Tested-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> # non-native/no RCEC
Signed-off-by: Sean V Kelley <sean.v.kelley@intel.com>
Signed-off-by: Qiuxu Zhuo <qiuxu.zhuo@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>

drivers/pci/pcie/portdrv_pci.c

@@ -106,7 +106,8 @@ static int pcie_portdrv_probe(struct pci_dev *dev,
 	if (!pci_is_pcie(dev) ||
 	    ((pci_pcie_type(dev) != PCI_EXP_TYPE_ROOT_PORT) &&
 	     (pci_pcie_type(dev) != PCI_EXP_TYPE_UPSTREAM) &&
-	     (pci_pcie_type(dev) != PCI_EXP_TYPE_DOWNSTREAM)))
+	     (pci_pcie_type(dev) != PCI_EXP_TYPE_DOWNSTREAM) &&
+	     (pci_pcie_type(dev) != PCI_EXP_TYPE_RC_EC)))
 		return -ENODEV;
 
 	status = pcie_port_device_register(dev);
@@ -195,6 +196,8 @@ static const struct pci_device_id port_pci_ids[] = {
 	{ PCI_DEVICE_CLASS(((PCI_CLASS_BRIDGE_PCI << 8) | 0x00), ~0) },
 	/* subtractive decode PCI-to-PCI bridge, class type is 060401h */
 	{ PCI_DEVICE_CLASS(((PCI_CLASS_BRIDGE_PCI << 8) | 0x01), ~0) },
+	/* handle any Root Complex Event Collector */
+	{ PCI_DEVICE_CLASS(((PCI_CLASS_SYSTEM_RCEC << 8) | 0x00), ~0) },
 	{ },
 };
 

include/linux/pci_ids.h

@@ -81,6 +81,7 @@
 #define PCI_CLASS_SYSTEM_RTC		0x0803
 #define PCI_CLASS_SYSTEM_PCI_HOTPLUG	0x0804
 #define PCI_CLASS_SYSTEM_SDHCI		0x0805
+#define PCI_CLASS_SYSTEM_RCEC		0x0807
 #define PCI_CLASS_SYSTEM_OTHER		0x0880
 
 #define PCI_BASE_CLASS_INPUT		0x09

include/uapi/linux/pci_regs.h

@@ -831,6 +831,13 @@
 #define  PCI_PWR_CAP_BUDGET(x)	((x) & 1)	/* Included in system budget */
 #define PCI_EXT_CAP_PWR_SIZEOF	16
 
+/* Root Complex Event Collector Endpoint Association  */
+#define PCI_RCEC_RCIEP_BITMAP	4	/* Associated Bitmap for RCiEPs */
+#define PCI_RCEC_BUSN		8	/* RCEC Associated Bus Numbers */
+#define  PCI_RCEC_BUSN_REG_VER	0x02	/* Least version with BUSN present */
+#define  PCI_RCEC_BUSN_NEXT(x)	(((x) >> 8) & 0xff)
+#define  PCI_RCEC_BUSN_LAST(x)	(((x) >> 16) & 0xff)
+
 /* Vendor-Specific (VSEC, PCI_EXT_CAP_ID_VNDR) */
 #define PCI_VNDR_HEADER		4	/* Vendor-Specific Header */
 #define  PCI_VNDR_HEADER_ID(x)	((x) & 0xffff)