From 959498f437634d91939b4a5cb6e319b34969a6b2 Mon Sep 17 00:00:00 2001
From: Geert Uytterhoeven <geert@linux-m68k.org>
Date: Thu, 17 Mar 2022 09:18:29 +0100
Subject: drm/ssd130x: Reduce temporary buffer sizes
Git-commit: 4442ac1af10442d6e7e824fdc226f89ed94d5b53
Patch-mainline: v5.19-rc1
References: jsc#PED-1166 jsc#PED-1168 jsc#PED-1170 jsc#PED-1218 jsc#PED-1220 jsc#PED-1222 jsc#PED-1223 jsc#PED-1225

ssd130x_clear_screen() allocates a temporary buffer sized to hold one
byte per pixel, while it only needs to hold one bit per pixel.

ssd130x_fb_blit_rect() allocates a temporary buffer sized to hold one
byte per pixel for the whole frame buffer, while it only needs to hold
one bit per pixel for the part that is to be updated.
Pass dst_pitch to drm_fb_xrgb8888_to_mono(), as we have already
calculated it anyway.

Fixes: a61732e808672cfa ("drm: Add driver for Solomon SSD130x OLED displays")
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Javier Martinez Canillas <javierm@redhat.com>
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220317081830.1211400-5-geert@linux-m68k.org
Acked-by: Patrik Jakobsson <pjakobsson@suse.de>
---
 drivers/gpu/drm/solomon/ssd130x.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/solomon/ssd130x.c b/drivers/gpu/drm/solomon/ssd130x.c
index 7c99af4ce9dd..38b6c2c14f53 100644
--- a/drivers/gpu/drm/solomon/ssd130x.c
+++ b/drivers/gpu/drm/solomon/ssd130x.c
@@ -440,7 +440,8 @@ static void ssd130x_clear_screen(struct ssd130x_device *ssd130x)
 		.y2 = ssd130x->height,
 	};
 
-	buf = kcalloc(ssd130x->width, ssd130x->height, GFP_KERNEL);
+	buf = kcalloc(DIV_ROUND_UP(ssd130x->width, 8), ssd130x->height,
+		      GFP_KERNEL);
 	if (!buf)
 		return;
 
@@ -454,6 +455,7 @@ static int ssd130x_fb_blit_rect(struct drm_framebuffer *fb, const struct iosys_m
 {
 	struct ssd130x_device *ssd130x = drm_to_ssd130x(fb->dev);
 	void *vmap = map->vaddr; /* TODO: Use mapping abstraction properly */
+	unsigned int dst_pitch;
 	int ret = 0;
 	u8 *buf = NULL;
 
@@ -461,11 +463,12 @@ static int ssd130x_fb_blit_rect(struct drm_framebuffer *fb, const struct iosys_m
 	rect->y1 = round_down(rect->y1, 8);
 	rect->y2 = min_t(unsigned int, round_up(rect->y2, 8), ssd130x->height);
 
-	buf = kcalloc(fb->width, fb->height, GFP_KERNEL);
+	dst_pitch = DIV_ROUND_UP(drm_rect_width(rect), 8);
+	buf = kcalloc(dst_pitch, drm_rect_height(rect), GFP_KERNEL);
 	if (!buf)
 		return -ENOMEM;
 
-	drm_fb_xrgb8888_to_mono(buf, 0, vmap, fb, rect);
+	drm_fb_xrgb8888_to_mono(buf, dst_pitch, vmap, fb, rect);
 
 	ssd130x_update_rect(ssd130x, buf, rect);
 
-- 
2.38.1