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From: Louis Chauvet <louis.chauvet@bootlin.com>
Date: Mon, 04 Mar 2024 16:28:11 +0100
Subject: [PATCH v4 06/14] drm/vkms: Use const for input pointers in
 pixel_read an pixel_write functions
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Message-Id: <20240304-yuv-v4-6-76beac8e9793@bootlin.com>
References: <20240304-yuv-v4-0-76beac8e9793@bootlin.com>
In-Reply-To: <20240304-yuv-v4-0-76beac8e9793@bootlin.com>
To: Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>, 
 Melissa Wen <melissa.srw@gmail.com>, 
 =?utf-8?q?Ma=C3=ADra_Canal?= <mairacanal@riseup.net>, 
 Haneen Mohammed <hamohammed.sa@gmail.com>, Daniel Vetter <daniel@ffwll.ch>, 
 Maarten Lankhorst <maarten.lankhorst@linux.intel.com>, 
 Maxime Ripard <mripard@kernel.org>, Thomas Zimmermann <tzimmermann@suse.de>, 
 David Airlie <airlied@gmail.com>, arthurgrillo@riseup.net, 
 Jonathan Corbet <corbet@lwn.net>, pekka.paalanen@haloniitty.fi
Cc: dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, 
 jeremie.dautheribes@bootlin.com, miquel.raynal@bootlin.com, 
 thomas.petazzoni@bootlin.com, seanpaul@google.com, marcheu@google.com, 
 nicolejadeyee@google.com, Louis Chauvet <louis.chauvet@bootlin.com>

As the pixel_read and pixel_write function should never modify the input
buffer, mark those pointers const.

Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
---
 drivers/gpu/drm/vkms/vkms_drv.h     |  4 ++--
 drivers/gpu/drm/vkms/vkms_formats.c | 24 ++++++++++++------------
 2 files changed, 14 insertions(+), 14 deletions(-)

diff --git a/drivers/gpu/drm/vkms/vkms_drv.h b/drivers/gpu/drm/vkms/vkms_drv.h
index 4bfc62d26f08..3ead8b39af4a 100644
--- a/drivers/gpu/drm/vkms/vkms_drv.h
+++ b/drivers/gpu/drm/vkms/vkms_drv.h
@@ -61,7 +61,7 @@ struct line_buffer {
  * @out_pixel: destination address to write the pixel
  * @in_pixel: pixel to write
  */
-typedef void (*pixel_write_t)(u8 *out_pixel, struct pixel_argb_u16 *in_pixel);
+typedef void (*pixel_write_t)(u8 *out_pixel, const struct pixel_argb_u16 *in_pixel);
 
 struct vkms_writeback_job {
 	struct iosys_map data[DRM_FORMAT_MAX_PLANES];
@@ -76,7 +76,7 @@ struct vkms_writeback_job {
  * @in_pixel: Pointer to the pixel to read
  * @out_pixel: Pointer to write the converted pixel
  */
-typedef void (*pixel_read_t)(u8 *in_pixel, struct pixel_argb_u16 *out_pixel);
+typedef void (*pixel_read_t)(const u8 *in_pixel, struct pixel_argb_u16 *out_pixel);
 
 /**
  * vkms_plane_state - Driver specific plane state
diff --git a/drivers/gpu/drm/vkms/vkms_formats.c b/drivers/gpu/drm/vkms/vkms_formats.c
index 29ca403827a6..bdd15964ce24 100644
--- a/drivers/gpu/drm/vkms/vkms_formats.c
+++ b/drivers/gpu/drm/vkms/vkms_formats.c
@@ -76,7 +76,7 @@ static int get_x_position(const struct vkms_frame_info *frame_info, int limit, i
  * They are used in the `vkms_compose_row` function to handle multiple formats.
  */
 
-static void ARGB8888_to_argb_u16(u8 *in_pixel, struct pixel_argb_u16 *out_pixel)
+static void ARGB8888_to_argb_u16(const u8 *in_pixel, struct pixel_argb_u16 *out_pixel)
 {
 	/*
 	 * The 257 is the "conversion ratio". This number is obtained by the
@@ -90,7 +90,7 @@ static void ARGB8888_to_argb_u16(u8 *in_pixel, struct pixel_argb_u16 *out_pixel)
 	out_pixel->b = (u16)in_pixel[0] * 257;
 }
 
-static void XRGB8888_to_argb_u16(u8 *in_pixel, struct pixel_argb_u16 *out_pixel)
+static void XRGB8888_to_argb_u16(const u8 *in_pixel, struct pixel_argb_u16 *out_pixel)
 {
 	out_pixel->a = (u16)0xffff;
 	out_pixel->r = (u16)in_pixel[2] * 257;
@@ -98,7 +98,7 @@ static void XRGB8888_to_argb_u16(u8 *in_pixel, struct pixel_argb_u16 *out_pixel)
 	out_pixel->b = (u16)in_pixel[0] * 257;
 }
 
-static void ARGB16161616_to_argb_u16(u8 *in_pixel, struct pixel_argb_u16 *out_pixel)
+static void ARGB16161616_to_argb_u16(const u8 *in_pixel, struct pixel_argb_u16 *out_pixel)
 {
 	u16 *pixel = (u16 *)in_pixel;
 
@@ -108,7 +108,7 @@ static void ARGB16161616_to_argb_u16(u8 *in_pixel, struct pixel_argb_u16 *out_pi
 	out_pixel->b = le16_to_cpu(pixel[0]);
 }
 
-static void XRGB16161616_to_argb_u16(u8 *in_pixel, struct pixel_argb_u16 *out_pixel)
+static void XRGB16161616_to_argb_u16(const u8 *in_pixel, struct pixel_argb_u16 *out_pixel)
 {
 	u16 *pixel = (u16 *)in_pixel;
 
@@ -118,7 +118,7 @@ static void XRGB16161616_to_argb_u16(u8 *in_pixel, struct pixel_argb_u16 *out_pi
 	out_pixel->b = le16_to_cpu(pixel[0]);
 }
 
-static void RGB565_to_argb_u16(u8 *in_pixel, struct pixel_argb_u16 *out_pixel)
+static void RGB565_to_argb_u16(const u8 *in_pixel, struct pixel_argb_u16 *out_pixel)
 {
 	u16 *pixel = (u16 *)in_pixel;
 
@@ -143,7 +143,7 @@ static void RGB565_to_argb_u16(u8 *in_pixel, struct pixel_argb_u16 *out_pixel)
  * It is used to avoid null pointer to be used as a function. In theory, this function should
  * never be called, except if you found a bug in the driver/DRM core.
  */
-static void black_to_argb_u16(u8 *in_pixel, struct pixel_argb_u16 *out_pixel)
+static void black_to_argb_u16(const u8 *in_pixel, struct pixel_argb_u16 *out_pixel)
 {
 	out_pixel->a = (u16) 0xFFFF;
 	out_pixel->r = 0;
@@ -189,7 +189,7 @@ void vkms_compose_row(struct line_buffer *stage_buffer, struct vkms_plane_state
  * They are used in the `vkms_writeback_row` to convert and store a pixel from the src_buffer to
  * the writeback buffer.
  */
-static void argb_u16_to_ARGB8888(u8 *out_pixel, struct pixel_argb_u16 *in_pixel)
+static void argb_u16_to_ARGB8888(u8 *out_pixel, const struct pixel_argb_u16 *in_pixel)
 {
 	/*
 	 * This sequence below is important because the format's byte order is
@@ -207,7 +207,7 @@ static void argb_u16_to_ARGB8888(u8 *out_pixel, struct pixel_argb_u16 *in_pixel)
 	out_pixel[0] = DIV_ROUND_CLOSEST(in_pixel->b, 257);
 }
 
-static void argb_u16_to_XRGB8888(u8 *out_pixel, struct pixel_argb_u16 *in_pixel)
+static void argb_u16_to_XRGB8888(u8 *out_pixel, const struct pixel_argb_u16 *in_pixel)
 {
 	out_pixel[3] = 0xff;
 	out_pixel[2] = DIV_ROUND_CLOSEST(in_pixel->r, 257);
@@ -215,7 +215,7 @@ static void argb_u16_to_XRGB8888(u8 *out_pixel, struct pixel_argb_u16 *in_pixel)
 	out_pixel[0] = DIV_ROUND_CLOSEST(in_pixel->b, 257);
 }
 
-static void argb_u16_to_ARGB16161616(u8 *out_pixel, struct pixel_argb_u16 *in_pixel)
+static void argb_u16_to_ARGB16161616(u8 *out_pixel, const struct pixel_argb_u16 *in_pixel)
 {
 	u16 *pixel = (u16 *)out_pixel;
 
@@ -225,7 +225,7 @@ static void argb_u16_to_ARGB16161616(u8 *out_pixel, struct pixel_argb_u16 *in_pi
 	pixel[0] = cpu_to_le16(in_pixel->b);
 }
 
-static void argb_u16_to_XRGB16161616(u8 *out_pixel, struct pixel_argb_u16 *in_pixel)
+static void argb_u16_to_XRGB16161616(u8 *out_pixel, const struct pixel_argb_u16 *in_pixel)
 {
 	u16 *pixel = (u16 *)out_pixel;
 
@@ -235,7 +235,7 @@ static void argb_u16_to_XRGB16161616(u8 *out_pixel, struct pixel_argb_u16 *in_pi
 	pixel[0] = cpu_to_le16(in_pixel->b);
 }
 
-static void argb_u16_to_RGB565(u8 *out_pixel, struct pixel_argb_u16 *in_pixel)
+static void argb_u16_to_RGB565(u8 *out_pixel, const struct pixel_argb_u16 *in_pixel)
 {
 	u16 *pixel = (u16 *)out_pixel;
 
@@ -260,7 +260,7 @@ static void argb_u16_to_RGB565(u8 *out_pixel, struct pixel_argb_u16 *in_pixel)
  * It is used to avoid null pointer to be used as a function. In theory, this should never
  * happen, except if there is a bug in the driver
  */
-static void argb_u16_to_nothing(u8 *out_pixel, struct pixel_argb_u16 *in_pixel) {}
+static void argb_u16_to_nothing(u8 *out_pixel, const struct pixel_argb_u16 *in_pixel) {}
 
 /**
  * Generic loop for all supported writeback format. It is executed just after the blending to

-- 
2.43.0