nvmem: brcm_nvram: store a copy of NVRAM content

This driver uses MMIO access for reading NVRAM from a flash device.
Underneath there is a flash controller that reads data and provides
mapping window.

Using MMIO interface affects controller configuration and may break real
controller driver. It was reported by multiple users of devices with
NVRAM stored on NAND.

Modify driver to read & cache NVRAM content during init and use that
copy to provide NVMEM data when requested. On NAND flashes due to their
alignment NVRAM partitions can be quite big (1 MiB and more) while
actual NVRAM content stays quite small (usually 16 to 32 KiB). To avoid
allocating so much memory check for actual data length.

Link: https://lore.kernel.org/linux-mtd/CACna6rwf3_9QVjYcM+847biTX=K0EoWXuXcSMkJO1Vy_5vmVqA@mail.gmail.com/
Fixes: 3fef9ed0627a ("nvmem: brcm_nvram: new driver exposing Broadcom's NVRAM")
Cc: <Stable@vger.kernel.org>
Cc: Arınç ÜNAL <arinc.unal@arinc9.com>
Cc: Florian Fainelli <florian.fainelli@broadcom.com>
Cc: Scott Branden <scott.branden@broadcom.com>
Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
Acked-by: Arınç ÜNAL <arinc.unal@arinc9.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20231215111358.316727-3-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: brcm_nvram: Use devm_platform_get_and_ioremap_resource()

Convert platform_get_resource(), devm_ioremap_resource() to a single
call to devm_platform_get_and_ioremap_resource(), as this is exactly
what this function does.

Signed-off-by: Yangtao Li <frank.li@vivo.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20230823132744.350618-4-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: brcm_nvram: add .read_post_process() for MACs

1. Parse ASCII MAC format into byte based
2. Calculate relative addresses based on index argument

Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Message-ID: <20230611140330.154222-5-srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: brcm_nvram: Add check for kzalloc

Add the check for the return value of kzalloc in order to avoid
NULL pointer dereference.

Fixes: 6e977eaa8280 ("nvmem: brcm_nvram: parse NVRAM content into NVMEM cells")
Cc: stable@vger.kernel.org
Signed-off-by: Jiasheng Jiang <jiasheng@iscas.ac.cn>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20230127104015.23839-2-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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>

nvmem: brcm_nvram: Use kzalloc for allocating only one element

Use kzalloc(...) rather than kcalloc(1, ...) because the number of
elements we are specifying in this case is 1, so kzalloc would
accomplish the same thing and we can simplify.

Signed-off-by: Kenneth Lee <klee33@uw.edu>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20220916122100.170016-6-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: brcm_nvram: find Device Tree nodes for NVMEM cells

DT binding for Broadcom's NVRAM supports specifying NVMEM cells as NVMEM
device (provider) subnodes. Look for such subnodes when collecing NVMEM
cells. This allows NVMEM consumers to use NVRAM variables.

Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20220429162701.2222-3-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: brcm_nvram: parse NVRAM content into NVMEM cells

NVRAM consist of header and NUL separated key-value pairs. Parse it and
create NVMEM cell for every key-value entry.

Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20220225175822.8293-3-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: brcm_nvram: new driver exposing Broadcom's NVRAM

This driver provides access to Broadcom's NVRAM.

Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20210330111241.19401-6-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>