firmware: coreboot: Replace tag with id table in driver struct

Switch the plain 'tag' field in struct coreboot_driver for the newly
created coreboot_device_id struct, which also contains a tag field and
has the benefit of allowing modalias generation, and update all coreboot
drivers accordingly.

While at it, also add the id table for each driver to the module device
table to allow automatically loading the module.

Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Reviewed-by: Brian Norris <briannorris@chromium.org>
Signed-off-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
Link: https://lore.kernel.org/r/20240212-coreboot-mod-defconfig-v4-3-d14172676f6d@collabora.com
Signed-off-by: Tzung-Bi Shih <tzungbi@kernel.org>

firmware: coreboot: Check size of table entry and use flex-array

The memcpy() of the data following a coreboot_table_entry couldn't
be evaluated by the compiler under CONFIG_FORTIFY_SOURCE. To make it
easier to reason about, add an explicit flexible array member to struct
coreboot_device so the entire entry can be copied at once. Additionally,
validate the sizes before copying. Avoids this run-time false positive
warning:

memcpy: detected field-spanning write (size 168) of single field "&device->entry" at drivers/firmware/google/coreboot_table.c:103 (size 8)

Reported-by: Paul Menzel <pmenzel@molgen.mpg.de>
Link: https://lore.kernel.org/all/03ae2704-8c30-f9f0-215b-7cdf4ad35a9a@molgen.mpg.de/
Cc: Jack Rosenthal <jrosenth@chromium.org>
Cc: Guenter Roeck <groeck@chromium.org>
Cc: Julius Werner <jwerner@chromium.org>
Cc: Brian Norris <briannorris@chromium.org>
Cc: Stephen Boyd <swboyd@chromium.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Julius Werner <jwerner@chromium.org>
Reviewed-by: Guenter Roeck <groeck@chromium.org>
Link: https://lore.kernel.org/r/20230107031406.gonna.761-kees@kernel.org
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Reviewed-by: Jack Rosenthal <jrosenth@chromium.org>
Link: https://lore.kernel.org/r/20230112230312.give.446-kees@kernel.org

firmware: google: Implement cbmem in sysfs driver

The CBMEM area is a downward-growing memory region used by coreboot to
dynamically allocate tagged data structures ("CBMEM entries") that
remain resident during boot.

This implements a driver which exports access to the CBMEM entries
via sysfs under /sys/bus/coreboot/devices/cbmem-<id>.

This implementation is quite versatile. Examples of how it could be
used are given below:

* Tools like util/cbmem from the coreboot tree could use this driver
instead of finding CBMEM in /dev/mem directly. Alternatively,
firmware developers debugging an issue may find the sysfs interface
more ergonomic than the cbmem tool and choose to use it directly.

* The crossystem tool, which exposes verified boot variables, can use
this driver to read the vboot work buffer.

* Tools which read the BIOS SPI flash (e.g., flashrom) can find the
flash layout in CBMEM directly, which is significantly faster than
searching the flash directly.

Write access is provided to all CBMEM regions via
/sys/bus/coreboot/devices/cbmem-<id>/mem, as the existing cbmem
tooling updates this memory region, and envisioned use cases with
crossystem can benefit from updating memory regions.

Link: https://issuetracker.google.com/239604743
Cc: Stephen Boyd <swboyd@chromium.org>
Cc: Tzung-Bi Shih <tzungbi@kernel.org>
Reviewed-by: Guenter Roeck <groeck@chromium.org>
Reviewed-by: Julius Werner <jwerner@chromium.org>
Tested-by: Jack Rosenthal <jrosenth@chromium.org>
Signed-off-by: Jack Rosenthal <jrosenth@chromium.org>
Link: https://lore.kernel.org/r/20221104161528.531248-1-jrosenth@chromium.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

firmware: google: make coreboot driver's remove callback return void

All coreboot drivers return 0 unconditionally in their remove callback.
Also the device core ignores the return value of the struct
bus_type::remove(), so make the coreboot remove callback return void
instead of giving driver authors the illusion they could return an error
code here.

All drivers are adapted accordingly.

Signed-off-by: Uwe Kleine-König <uwe@kleine-koenig.org>
Link: https://lore.kernel.org/r/20210126215339.706021-1-uwe@kleine-koenig.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 287

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 v2 0 as
published by the free software foundation this program is
distributed in the hope that it will be useful but without any
warranty without even the implied warranty of merchantability or
fitness for a particular purpose see the gnu general public license
for more details

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-only

has been chosen to replace the boilerplate/reference in 23 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexios Zavras <alexios.zavras@intel.com>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190529141901.115786599@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

firmware: google: coreboot: Drop unnecessary headers

These headers aren't used by the files they're included in, so drop
them. The memconsole file uses memremap() though, so include io.h there
so that the include is explicit.

Cc: Wei-Ning Huang <wnhuang@chromium.org>
Cc: Julius Werner <jwerner@chromium.org>
Cc: Brian Norris <briannorris@chromium.org>
Cc: Samuel Holland <samuel@sholland.org>
Cc: Guenter Roeck <groeck@chromium.org>
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Reviewed-by: Julius Werner <jwerner@chromium.org>
Reviewed-by: Samuel Holland <samuel@sholland.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

firmware: google: Add a module_coreboot_driver() macro and use it

Remove some boiler plate code we have in three drivers with a single
line each time. This also gets us a free assignment of the driver .owner
field, making these drivers work better as modules.

Cc: Wei-Ning Huang <wnhuang@chromium.org>
Cc: Julius Werner <jwerner@chromium.org>
Cc: Brian Norris <briannorris@chromium.org>
Cc: Samuel Holland <samuel@sholland.org>
Cc: Guenter Roeck <groeck@chromium.org>
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Reviewed-by: Julius Werner <jwerner@chromium.org>
Reviewed-by: Samuel Holland <samuel@sholland.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

firmware: coreboot: Collapse platform drivers into bus core

The DT based and ACPI based platform drivers here do the same thing; map
some memory and hand it over to the coreboot bus to populate devices.
The only major difference is that the DT based driver doesn't map the
coreboot table header to figure out how large of a region to map for the
whole coreboot table and it uses of_iomap() instead of ioremap_cache().
A cached or non-cached mapping shouldn't matter here and mapping some
smaller region first before mapping the whole table is just more work
but should be OK. In the end, we can remove two files and combine the
code all in one place making it easier to reason about things.

We leave the old Kconfigs in place for a little while longer but make
them hidden and select the previously hidden config option. This way
users can upgrade without having to know to reselect this config in the
future. Later on we can remove the old hidden configs.

Cc: Wei-Ning Huang <wnhuang@chromium.org>
Cc: Julius Werner <jwerner@chromium.org>
Cc: Brian Norris <briannorris@chromium.org>
Cc: Samuel Holland <samuel@sholland.org>
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Reviewed-by: Julius Werner <jwerner@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

firmware: coreboot: Add coreboot framebuffer driver

Register a simplefb framebuffer when the coreboot table contains a
framebuffer entry.

Signed-off-by: Samuel Holland <samuel@sholland.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

firmware: coreboot: Remove unused coreboot_table_find

Now that all users of the coreboot_table_find function have been updated
to hang off the coreboot table bus instead, remove it.

Signed-off-by: Samuel Holland <samuel@sholland.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

firmware: coreboot: Expose the coreboot table as a bus

This simplifies creating device drivers for hardware or information
described in the coreboot table. It also avoids needing to search
through the table every time a driver is loaded.

Signed-off-by: Samuel Holland <samuel@sholland.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

firmware: google memconsole: Add coreboot support

Coreboot (http://www.coreboot.org) allows to save the firmware console
output in a memory buffer. With this patch, the address of this memory
buffer is obtained from coreboot tables on x86 chromebook devices
declaring an ACPI device with name matching GOOGCB00 or BOOT0000.

If the memconsole-coreboot driver is able to find the coreboot table,
the memconsole driver sets the cbmem_console address and initializes the
memconsole sysfs entries.

The coreboot_table-acpi driver is responsible for setting the address of
the coreboot table header when probed. If this address is not yet set
when memconsole-coreboot is probed, then the probe is deferred by
returning -EPROBE_DEFER.

This patch is a rework/split/merge of patches from the chromeos v4.4
kernel tree originally authored by:
Vadim Bendebury <vbendeb@chromium.org>
Wei-Ning Huang <wnhuang@google.com>
Yuji Sasaki <sasakiy@google.com>
Duncan Laurie <dlaurie@chromium.org>
Julius Werner <jwerner@chromium.org>
Brian Norris <briannorris@chromium.org>

Signed-off-by: Thierry Escande <thierry.escande@collabora.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>