PCI/AER: Decode Requester ID when no error info found

When a device with AER detects an error, it logs error information in its
own AER Error Status registers.  It may send an Error Message to the Root
Port (RCEC in the case of an RCiEP), which logs the fact that an Error
Message was received (Root Error Status) and the Requester ID of the
message source (Error Source Identification).

aer_print_port_info() prints the Requester ID from the Root Port Error
Source in the usual Linux "bb:dd.f" format, but when find_source_device()
finds no error details in the hierarchy below the Root Port, it printed the
raw Requester ID without decoding it.

Decode the Requester ID in the usual Linux format so it matches other
messages.

Sample message changes:

  - pcieport 0000:00:1c.5: AER: Correctable error received: 0000:00:1c.5
  - pcieport 0000:00:1c.5: AER: can't find device of ID00e5
  + pcieport 0000:00:1c.5: AER: Correctable error message received from 0000:00:1c.5
  + pcieport 0000:00:1c.5: AER: found no error details for 0000:00:1c.5

Link: https://lore.kernel.org/r/20231206224231.732765-3-helgaas@kernel.orgSigned-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/aer.c

@@ -740,7 +740,7 @@ static void aer_print_port_info(struct pci_dev *dev, struct aer_err_info *info)
 	u8 bus = info->id >> 8;
 	u8 devfn = info->id & 0xff;
 
-	pci_info(dev, "%s%s error received: %04x:%02x:%02x.%d\n",
+	pci_info(dev, "%s%s error message received from %04x:%02x:%02x.%d\n",
 		 info->multi_error_valid ? "Multiple " : "",
 		 aer_error_severity_string[info->severity],
 		 pci_domain_nr(dev->bus), bus, PCI_SLOT(devfn),
@@ -929,7 +929,12 @@ static bool find_source_device(struct pci_dev *parent,
 		pci_walk_bus(parent->subordinate, find_device_iter, e_info);
 
 	if (!e_info->error_dev_num) {
-		pci_info(parent, "can't find device of ID%04x\n", e_info->id);
+		u8 bus = e_info->id >> 8;
+		u8 devfn = e_info->id & 0xff;
+
+		pci_info(parent, "found no error details for %04x:%02x:%02x.%d\n",
+			 pci_domain_nr(parent->bus), bus, PCI_SLOT(devfn),
+			 PCI_FUNC(devfn));
 		return false;
 	}
 	return true;