PCI: Don't expose pcie_read_tlp_log() outside PCI subsystem

pcie_read_tlp_log() was exposed by the commit 0a5a46a ("PCI/AER:
Generalize TLP Header Log reading") with the intent that drivers could use
it, but the PCI maintainer later decided that drivers should be encouraged
to use PCI core diagnostic logging of generic AER registers rather than
building their own.

Drivers that currently implement their own diagnostic logging include ixgbe
(ixgbe_io_error_detected()) and iwlwifi (iwl_trans_pcie_dump_regs()).

Remove the unwanted EXPORT of pcie_read_tlp_log() and remove it from
include/linux/aer.h.

Link: https://lore.kernel.org/r/[email protected]
Link: https://lore.kernel.org/all/20240322193011.GA701027@bhelgaas/
Signed-off-by: Ilpo Järvinen <[email protected]>
[bhelgaas: commit log]
Signed-off-by: Bjorn Helgaas <[email protected]>
Reviewed-by: Jonathan Cameron <[email protected]>
Reviewed-by: Yazen Ghannam <[email protected]>

Author: ij-intel

drivers/pci/pci.c

@@ -1125,7 +1125,6 @@ int pcie_read_tlp_log(struct pci_dev *dev, int where,
 
 	return 0;
 }
-EXPORT_SYMBOL_GPL(pcie_read_tlp_log);
 
 /**
  * pci_restore_bars - restore a device's BAR values (e.g. after wake-up)

drivers/pci/pci.h

@@ -4,6 +4,8 @@
 
 #include <linux/pci.h>
 
+struct pcie_tlp_log;
+
 /* Number of possible devfns: 0.0 to 1f.7 inclusive */
 #define MAX_NR_DEVFNS 256
 
@@ -549,6 +551,8 @@ 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 */
 
+int pcie_read_tlp_log(struct pci_dev *dev, int where, struct pcie_tlp_log *log);
+
 #ifdef CONFIG_PCIEPORTBUS
 /* Cached RCEC Endpoint Association */
 struct rcec_ea {

include/linux/aer.h

@@ -37,8 +37,6 @@ struct aer_capability_regs {
 	u16 uncor_err_source;
 };
 
-int pcie_read_tlp_log(struct pci_dev *dev, int where, struct pcie_tlp_log *log);
-
 #if defined(CONFIG_PCIEAER)
 int pci_aer_clear_nonfatal_status(struct pci_dev *dev);
 int pcie_aer_is_native(struct pci_dev *dev);