Documentation: PCI: Tidy AER documentation

Consistently use:

PCIe previously PCIe, PCI Express, or pci express
Root Port previously Root Port or root port
Endpoint previously EndPoint or endpoint
AER previously AER or aer
please previously pls

Also update a few awkward wordings.

Link: https://lore.kernel.org/r/20230609222500.1267795-5-helgaas@kernel.org
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Stefan Roese <sr@denx.de>
Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>

Documentation: PCI: Update cross references to .rst files

Change references to *.txt to *.rst to match the current filenames.

Link: https://lore.kernel.org/r/20230609222500.1267795-4-helgaas@kernel.org
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Stefan Roese <sr@denx.de>
Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>

Documentation: PCI: Drop recommendation to configure AER Capability

Since f26e58bf6f54 ("PCI/AER: Enable error reporting when AER is native"),
the PCI core enables PCIe device error reporting for all devices during
enumeration, so drivers don't need to do it.

Remove the recommendation for drivers to configure AER and call
pci_enable_pcie_error_reporting() themselves.

Also remove the suggestion that drivers may change AER mask and severity
registers. Ownership of these registers is negotiated between the OS and
platform firmware. If firmware owns these registers, the OS must not
change them.

Link: https://lore.kernel.org/r/20230609222500.1267795-3-helgaas@kernel.org
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Reviewed-by: Stefan Roese <sr@denx.de>
Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>

PCI/AER: Rationalize error status register clearing

The AER interfaces to clear error status registers were a confusing mess:

- pci_cleanup_aer_uncorrect_error_status() cleared non-fatal errors
from the Uncorrectable Error Status register.

- pci_aer_clear_fatal_status() cleared fatal errors from the
Uncorrectable Error Status register.

- pci_cleanup_aer_error_status_regs() cleared the Root Error Status
register (for Root Ports), the Uncorrectable Error Status register,
and the Correctable Error Status register.

Rename them to make them consistent:

From To
---------------------------------------- -------------------------------
pci_cleanup_aer_uncorrect_error_status() pci_aer_clear_nonfatal_status()
pci_aer_clear_fatal_status() pci_aer_clear_fatal_status()
pci_cleanup_aer_error_status_regs() pci_aer_clear_status()

Since pci_cleanup_aer_error_status_regs() (renamed to
pci_aer_clear_status()) is only used within drivers/pci/, move the
declaration from <linux/aer.h> to drivers/pci/pci.h.

[bhelgaas: commit log, add renames]
Link: https://lore.kernel.org/r/d1310a75dc3d28f7e8da4e99c45fbd3e60fe238e.1585000084.git.sathyanarayanan.kuppuswamy@linux.intel.com
Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

PCI/ERR: Remove service dependency in pcie_do_recovery()

Previously we passed the PCIe service type parameter to pcie_do_recovery(),
where reset_link() looked up the underlying pci_port_service_driver and its
.reset_link() function pointer. Instead of using this roundabout way, we
can just pass the driver-specific .reset_link() callback function when
calling pcie_do_recovery() function.

This allows us to call pcie_do_recovery() from code that is not a PCIe port
service driver, e.g., Error Disconnect Recover (EDR) support.

Remove pcie_port_find_service() and pcie_port_service_driver.reset_link
since they are now unused.

Link: https://lore.kernel.org/r/60e02b87b526cdf2930400059d98704bf0a147d1.1585000084.git.sathyanarayanan.kuppuswamy@linux.intel.com
Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

Documentation: PCI: convert pcieaer-howto.txt to reST

Convert plain text documentation to reStructuredText format and add it to
Sphinx TOC tree. No essential content change.

Signed-off-by: Changbin Du <changbin.du@gmail.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>