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Marek Behún 39bd54d43b Revert "PCI: aardvark: Fix support for PCI_ROM_ADDRESS1 on emulated bridge" 
This reverts commit 239edf686c.

239edf686c ("PCI: aardvark: Fix support for PCI_ROM_ADDRESS1 on emulated
bridge") added support for the Type 1 Expansion ROM BAR at config offset
0x38, based on the register being listed in the Marvell Armada A3720 spec.
But the spec doesn't document it at all for RC mode, and there is no ROM in
the SOC, so remove this emulation for now.

The PCI bridge which represents aardvark's PCIe Root Port has an Expansion
ROM Base Address register at offset 0x30, but its meaning is different than
PCI's Expansion ROM BAR register, although the layout is the same.  (This
is why we thought it does the same thing.)

First: there is no ROM (or part of BootROM) in the A3720 SOC dedicated for
PCIe Root Port (or controller in RC mode) containing executable code that
would initialize the Root Port, suitable for execution in bootloader (this
is how Expansion ROM BAR is used on x86).

Second: in A3720 spec the register (address 0xD0070030) is not documented
at all for Root Complex mode, but similar to other BAR registers, it has an
"entangled partner" in register 0xD0075920, which does address translation
for the BAR in 0xD0070030:

  - the BAR register sets the address from the view of PCIe bus

  - the translation register sets the address from the view of the CPU

The other BAR registers also have this entangled partner, and they can be
used to:

  - in RC mode: address-checking on the receive side of the RC (they can
    define address ranges for memory accesses from remote Endpoints to the
    RC)

  - in Endpoint mode: allow the remote CPU to access memory on A3720

The Expansion ROM BAR has only the Endpoint part documented, but from the
similarities we think that it can also be used in RC mode in that way.

So either Expansion ROM BAR has different meaning (if the hypothesis above
is true), or we don't know it's meaning (since it is not documented for RC
mode).

Remove the register from the emulated bridge accessing functions.

[bhelgaas: summarize reason for removal (first paragraph)]
Fixes: 239edf686c ("PCI: aardvark: Fix support for PCI_ROM_ADDRESS1 on emulated bridge")
Link: https://lore.kernel.org/r/20211125160148.26029-3-kabel@kernel.org
Signed-off-by: Marek Behún <kabel@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Pali Rohár <pali@kernel.org>
2021-12-01 21:49:18 -06:00
arch parisc architecture build-, trace-, backtrace- and page table fixes 2021-11-14 11:53:59 -08:00
block blk-mq: fix filesystem I/O request allocation 2021-11-12 09:31:13 -07:00
certs certs: Add support for using elliptic curve keys for signing modules 2021-08-23 19:55:42 +03:00
crypto Update to zstd-1.4.10 2021-11-13 15:32:30 -08:00
Documentation Devicetree fixes for v5.16, take 1: 2021-11-14 11:11:51 -08:00
drivers Revert "PCI: aardvark: Fix support for PCI_ROM_ADDRESS1 on emulated bridge" 2021-12-01 21:49:18 -06:00
fs Minor tweaks for 5.16: 2021-11-14 12:18:22 -08:00
include Devicetree fixes for v5.16, take 1: 2021-11-14 11:11:51 -08:00
init kconfig: Add support for -Wimplicit-fallthrough 2021-11-14 13:27:30 -08:00
ipc ipc/ipc_sysctl.c: remove fallback for !CONFIG_PROC_SYSCTL 2021-11-09 10:02:53 -08:00
kernel A single fix for POSIX CPU timers to address a problem where POSIX CPU 2021-11-14 10:43:38 -08:00
lib Update to zstd-1.4.10 2021-11-13 15:32:30 -08:00
LICENSES LICENSES/dual/CC-BY-4.0: Git rid of "smart quotes" 2021-07-15 06:31:24 -06:00
mm Revert "mm: shmem: don't truncate page if memory failure happens" 2021-11-13 12:03:03 -08:00
net One notable change here is that async creates and unlinks introduced 2021-11-13 11:31:07 -08:00
samples Add gitignore file for samples/fanotify/ subdirectory 2021-11-07 11:19:24 -08:00
scripts coccinelle patches for 5.16-rc1 2021-11-13 10:45:17 -08:00
security net,lsm,selinux: revert the security_sctp_assoc_established() hook 2021-11-12 12:07:02 -05:00
sound sound fixes for 5.16-rc1 2021-11-12 12:17:30 -08:00
tools A single fix for static calls to make the trampoline patching more robust 2021-11-14 10:30:17 -08:00
usr initramfs: Check timestamp to prevent broken cpio archive 2021-10-24 13:48:40 +09:00
virt KVM: generalize "bugged" VM to "dead" VM 2021-11-11 10:35:26 -05:00
.clang-format clang-format: Update with the latest for_each macro list 2021-05-12 23:32:39 +02:00
.cocciconfig
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore .gitignore: ignore only top-level modules.builtin 2021-05-02 00:43:35 +09:00
.mailmap Merge branch 'akpm' (patches from Andrew) 2021-11-09 10:11:53 -08:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Move Daniel Drake to credits 2021-09-21 08:34:58 +03:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS - Add the model number of a new, Raptor Lake CPU, to intel-family.h 2021-11-14 09:29:03 -08:00
Makefile Linux 5.16-rc1 2021-11-14 13:56:52 -08:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

README 

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.