firmware/nvram: bcm47xx: support init from IO memory

Provide NVMEM content to the NVRAM driver from a simple
memory resource. This is necessary to use NVRAM in a memory-
mapped flash device. Patch taken from OpenWrts development
tree.

This patch makes it possible to use memory-mapped NVRAM
on the D-Link DWL-8610AP and the D-Link DIR-890L.

Cc: Hauke Mehrtens <hauke@hauke-m.de>
Cc: linux-mips@vger.kernel.org
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: bcm-kernel-feedback-list@broadcom.com
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
[Added an export for modules potentially using the init symbol]
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20221103082529.359084-1-linus.walleij@linaro.org
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152

Based on 1 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation either version 2 of the license or at
your option any later version

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 3029 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

bcm47xx: Fix build regression

Commit 0bc2d534708b ("rcu: Refactor #includes from include/linux/rcupdate.h")
caused a build regression in an MTD partition driver:

In file included from drivers/mtd/bcm47xxpart.c:12:0:
include/linux/bcm47xx_nvram.h: In function 'bcm47xx_nvram_init_from_mem':
include/linux/bcm47xx_nvram.h:27:10: error: 'ENOTSUPP' undeclared (first use in this function)

The rcupdate.h file has no particular need for linux/errno.h, so this
commit includes linux/errno.h into bcm47xx_nvram.h.

Fixes: 0bc2d534708b ("rcu: Refactor #includes from include/linux/rcupdate.h")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

MIPS: BCM47xx: Move NVRAM driver to the drivers/firmware/

After Broadcom switched from MIPS to ARM for their home routers we need
to have NVRAM driver in some common place (not arch/mips/). As explained
in Kconfig, this driver is responsible for parsing SoC configuration
data that is passed to the kernel in flash from the bootloader firmware
called "CFE".

We were thinking about putting it in bus directory, however there are
two possible buses for MIPS: drivers/ssb/ and drivers/bcma/. So this
won't fit there and this is why I would like to move this driver to the
drivers/firmware/.

Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
Reviewed-by: Paul Walmsley <paul@pwsan.com>
Cc: linux-mips@linux-mips.org
Cc: Hauke Mehrtens <hauke@hauke-m.de>
Cc: Seiji Aguchi <seiji.aguchi@hds.com>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Mike Waychison <mikew@google.com>
Cc: Roy Franz <roy.franz@linaro.org>
Cc: Matt Fleming <matt.fleming@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Patchwork: https://patchwork.linux-mips.org/patch/10544/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

mips: bcm47xx: allow retrieval of complete nvram contents

Host platforms such as routers supported by OpenWrt can
support NVRAM reading directly from internal NVRAM store.
The brcmfmac for one requires the complete nvram contents
to select what needs to be sent to wireless device.

Signed-off-by: Arend van Spriel <arend@broadcom.com>
Signed-off-by: Hante Meuleman <meuleman@broadcom.com>
Reviewed-by: Arend Van Spriel <arend@broadcom.com>
Reviewed-by: Franky (Zhenhui) Lin <frankyl@broadcom.com>
Reviewed-by: Pieter-Paul Giesberts <pieterpg@broadcom.com>
Reviewed-by: Daniel (Deognyoun) Kim <dekim@broadcom.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/10093/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: BCM47xx: Move NVRAM header to the include/linux/.

There are two reasons for having this header in the common place:
1) Simplifying drivers that read NVRAM entries. We will be able to
safely call bcm47xx_nvram_* functions without #ifdef-s.
2) Getting NVRAM driver out of MIPS arch code. This is needed to support
BCM5301X arch which also requires this NVRAM driver. Patch for that
will follow once we get is reviewed.

Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
Acked-by: Hauke Mehrtens <hauke@hauke-m.de>
Cc: linux-mips@linux-mips.org
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Paul Walmsley <paul@pwsan.com>
Cc: linux-soc@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/8619/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>