PCI/AER: Add RCEC AER error injection support

mainline inclusion
from mainline-v5.11-rc1
commit d292dd0e
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I51U4T
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=d292dd0eb3ac6ce6ea66715bb9f6b8e2ae70747c

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Root Complex Event Collectors (RCEC) appear as peers to Root Ports and may
also have the AER capability.

Add RCEC support to the AER error injection driver.
Co-developed-by: NSean V Kelley <sean.v.kelley@intel.com>
Link: https://lore.kernel.org/r/20201121001036.8560-16-sean.v.kelley@intel.com
Tested-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> # non-native/no RCEC
Signed-off-by: NQiuxu Zhuo <qiuxu.zhuo@intel.com>
Signed-off-by: NSean V Kelley <sean.v.kelley@intel.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Signed-off-by: NJiefeng Ou <oujiefeng@h-partners.com>
Reviewed-by: NKuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Reviewed-by: NJay Fang <f.fangjian@huawei.com>
Reviewed-by: NXiongfeng Wang <wangxiongfeng2@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

drivers/pci/pcie/aer_inject.c

@@ -341,8 +341,11 @@ static int aer_inject(struct aer_error_inj *einj)
 	if (!dev)
 		return -ENODEV;
 	rpdev = pcie_find_root_port(dev);
+	/* If Root Port not found, try to find an RCEC */
+	if (!rpdev)
+		rpdev = dev->rcec;
 	if (!rpdev) {
-		pci_err(dev, "Root port not found\n");
+		pci_err(dev, "Neither Root Port nor RCEC found\n");
 		ret = -ENODEV;
 		goto out_put;
 	}