fbdev/arcfb: Use generator macros for deferred I/O

Implement the driver's fops with the generator macros for deferred
I/O. Only requires per-driver code for the on-scren scanout buffer.
The generated helpers implement reading, writing and drawing on top
of that. Also update the selected Kconfig tokens accordingly.

Actual support for deferred I/O is missing from the driver. So
writing to memory-mapped pages does not automatically update the
scanout buffer.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Jaya Kumar <jayalk@intworks.biz>
Acked-by: Javier Martinez Canillas <javierm@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231127131655.4020-7-tzimmermann@suse.de

fbdev/arcfb: Set FBINFO_VIRTFB flag

The arcfb driver operates on system memory. Mark the framebuffer
accordingly. Helpers operating on the framebuffer memory will test
for the presence of this flag.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Jaya Kumar <jayalk@intworks.biz>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231127131655.4020-6-tzimmermann@suse.de

fbdev: Remove FBINFO_FLAG_DEFAULT from framebuffer_alloc()'ed structs

The flag FBINFO_FLAG_DEFAULT is 0 and has no effect, as struct
fbinfo.flags has been allocated to zero by framebuffer_alloc(). So
do not set it.

Flags should signal differences from the default values. After cleaning
up all occurrences of FBINFO_DEFAULT, the token will be removed.

v4:
* clarify commit message (Geert, Dan)
v2:
* fix commit message (Miguel)

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Cc: Jaya Kumar <jayalk@intworks.biz>
Cc: Helge Deller <deller@gmx.de>
Cc: Peter Jones <pjones@redhat.com>
Cc: Sascha Hauer <s.hauer@pengutronix.de>
Cc: Pengutronix Kernel Team <kernel@pengutronix.de>
Cc: Shawn Guo <shawnguo@kernel.org>
Cc: Fabio Estevam <festevam@gmail.com>
Cc: NXP Linux Team <linux-imx@nxp.com>
Cc: Maik Broemme <mbroemme@libmpq.org>
Cc: Jingoo Han <jingoohan1@gmail.com>
Cc: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Cc: Teddy Wang <teddy.wang@siliconmotion.com>
Cc: Michal Januszewski <spock@gentoo.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230715185343.7193-15-tzimmermann@suse.de

fbdev: arcfb: Convert to platform remove callback returning void

The .remove() callback for a platform driver returns an int which makes
many driver authors wrongly assume it's possible to do error handling by
returning an error code. However the value returned is (mostly) ignored
and this typically results in resource leaks. To improve here there is a
quest to make the remove callback return void. In the first step of this
quest all drivers are converted to .remove_new() which already returns
void.

Trivially convert this driver from always returning zero in the remove
callback to the void returning variant.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Helge Deller <deller@gmx.de>

fbdev: Include <linux/io.h> in various drivers

The code uses writel() and similar I/O-memory helpers. Include
the header file to get the declarations.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Reviewed-by: Sui Jingfeng <suijingfeng@loongson.cn>
Link: https://patchwork.freedesktop.org/patch/msgid/20230512102444.5438-5-tzimmermann@suse.de

fbdev: arcfb: Fix error handling in arcfb_probe()

Smatch complains that:
arcfb_probe() warn: 'irq' from request_irq() not released on lines: 587.

Fix error handling in the arcfb_probe() function. If IO addresses are
not provided or framebuffer registration fails, the code will jump to
the err_addr or err_register_fb label to release resources.
If IRQ request fails, previously allocated resources will be freed.

Fixes: 1154ea7dcd8e ("[PATCH] Framebuffer driver for Arc LCD board")
Signed-off-by: Zongjie Li <u202112089@hust.edu.cn>
Reviewed-by: Dongliang Mu <dzm91@hust.edu.cn>
Signed-off-by: Helge Deller <deller@gmx.de>

fbdev: Validate info->screen_{base, buffer} in fb_ops implementations

Push the test for info->screen_base from fb_read() and fb_write() into
the implementations of struct fb_ops.{fb_read,fb_write}. In cases where
the driver operates on info->screen_buffer, test this field instead.

While bothi fields, screen_base and screen_buffer, are stored in the
same location, they refer to different address spaces. For correctness,
we want to test each field in exactly the code that uses it.

v2:
* also test screen_base in pvr2fb (Geert)
* also test screen_buffer in ivtvfb, arcfb, broadsheetfb,
hecubafb, metronomefb and ssd1307fb (Geert)
* give a rational for the change (Geert)

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Tested-by: Sui Jingfeng <suijingfeng@loongson.cn>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Acked-by: Helge Deller <deller@gmx.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20230428122452.4856-18-tzimmermann@suse.de

fbdev/arcfb: Use struct fb_info.screen_buffer

Use info->screen_buffer when reading and writing framebuffers in
system memory. It's the correct pointer for this address space.

The struct fb_info has a union to store the framebuffer memory. This can
either be info->screen_base if the framebuffer is stored in I/O memory,
or info->screen_buffer if the framebuffer is stored in system memory.

As the driver operates on the latter address space, it is wrong to use
.screen_base and .screen_buffer must be used instead. This also gets
rid of casting needed due to not using the correct data type.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230428122452.4856-5-tzimmermann@suse.de

video: fbdev: arcfb: remove redundant initialization of variable err

The variable err is being initialized with a value that is never
read, the assignment is redundant and can be removed.

Addresses-Coverity: ("Unused value")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20210721102608.42694-1-colin.king@canonical.com

treewide: Use fallthrough pseudo-keyword

Replace the existing /* fall through */ comments and its variants with
the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary
fall-through markings when it is the case.

[1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through

Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>

fbdev: Use fallthrough pseudo-keyword

Replace the existing /* fall through */ comments and its variants with
the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary
fall-through markings when it is the case.

[1] https://www.kernel.org/doc/html/latest/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through

Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20200707210539.GA12530@embeddedor

video: fbdev: arcfb: add missed free_irq and fix the order of request_irq

The driver forgets to free irq in remove which is requested in
probe.
Add the missed call to fix it.
Also, the position of request_irq() in probe should be put before
register_framebuffer().

Signed-off-by: Chuhong Yuan <hslester96@gmail.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200324132353.21785-1-hslester96@gmail.com

video: constify fb ops across all drivers

Now that the fbops member of struct fb_info is const, we can start
making the ops const as well.

This does not cover all drivers; some actually modify the fbops struct,
for example to adjust for different configurations, and others do more
involved things that I'd rather not touch in practically obsolete
drivers. Mostly this is the low hanging fruit where we can add "const"
and be done with it.

v3:
- un-constify atyfb, mb862xx, nvidia and uvesabf (0day)

v2:
- fix typo (Christophe de Dinechin)
- use "static const" instead of "const static" in mx3fb.c
- also constify smscufx.c

Cc: linux-fbdev@vger.kernel.org
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/ce67f14435f3af498f2e8bf35ce4be11f7504132.1575390740.git.jani.nikula@intel.com

video: fbdev: arcfb: mark expected switch fall-through

In preparation to enabling -Wimplicit-fallthrough, mark switch cases
where we are expecting to fall through.

Addresses-Coverity-ID: 115017 ("Missing break in switch")
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Cc: Jaya Kumar <jayalk@intworks.biz>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>

Annotate hardware config module parameters in drivers/video/

When the kernel is running in secure boot mode, we lock down the kernel to
prevent userspace from modifying the running kernel image. Whilst this
includes prohibiting access to things like /dev/mem, it must also prevent
access by means of configuring driver modules in such a way as to cause a
device to access or modify the kernel image.

To this end, annotate module_param* statements that refer to hardware
configuration and indicate for future reference what type of parameter they
specify. The parameter parser in the core sees this information and can
skip such parameters with an error message if the kernel is locked down.
The module initialisation then runs as normal, but just sees whatever the
default values for those parameters is.

Note that we do still need to do the module initialisation because some
drivers have viable defaults set in case parameters aren't specified and
some drivers support automatic configuration (e.g. PNP or PCI) in addition
to manually coded parameters.

This patch annotates drivers in drivers/video/.

Suggested-by: Alan Cox <gnomes@lxorguk.ukuu.org.uk>
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
cc: linux-fbdev@vger.kernel.org

video: fbdev: constify fb_fix_screeninfo and fb_var_screeninfo structures

These structures are only used to copy into other structures, so declare
them as const.

The semantic patch that makes this change in the fb_fix_screeninfo case is
as follows (http://coccinelle.lip6.fr/). The fb_var_screeninfo case is
analogous.

// <smpl>
@r disable optional_qualifier@
identifier i;
position p;
@@
static struct fb_fix_screeninfo i@p = { ... };

@ok@
identifier r.i;
expression e;
position p;
@@
e = i@p

@bad@
position p != {r.p,ok.p};
identifier r.i;
struct fb_fix_screeninfo e;
@@
e@i@p

@depends on !bad disable optional_qualifier@
identifier r.i;
@@
static
+const
struct fb_fix_screeninfo i = { ... };
// </smpl>

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>

video: move fbdev to drivers/video/fbdev

The drivers/video directory is a mess. It contains generic video related
files, directories for backlight, console, linux logo, lots of fbdev
device drivers, fbdev framework files.

Make some order into the chaos by creating drivers/video/fbdev
directory, and move all fbdev related files there.

No functionality is changed, although I guess it is possible that some
subtle Makefile build order related issue could be created by this
patch.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Rob Clark <robdclark@gmail.com>
Acked-by: Jingoo Han <jg1.han@samsung.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>