Thread (30 messages) 30 messages, 4 authors, 2023-07-06

Re: [PATCH 01/10] fbdev: Add fb_ops init macros for framebuffers in DMA-able memory

From: Javier Martinez Canillas <javierm@redhat.com>
Date: 2023-07-05 08:23:45
Also in: dri-devel, linux-arm-kernel, linux-samsung-soc, linux-tegra

Thomas Zimmermann [off-list ref] writes:

Hello Thomas,
quoted hunk ↗ jump to hunk
Add initializer macros for struct fb_ops for framebuffers in DMA-able
memory areas. Also add a corresponding Kconfig token. As of now, this
is equivalent to system framebuffers and mostly useful for labeling
drivers correctly.

A later patch may add a generic DMA-specific mmap operation. Linux
offers a number of dma_mmap_*() helpers for different use cases.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Helge Deller <deller@gmx.de>
---
 drivers/video/fbdev/Kconfig |  8 ++++++++
 include/linux/fb.h          | 13 +++++++++++++
 2 files changed, 21 insertions(+)
diff --git a/drivers/video/fbdev/Kconfig b/drivers/video/fbdev/Kconfig
index cecf15418632..f14229757311 100644
--- a/drivers/video/fbdev/Kconfig
+++ b/drivers/video/fbdev/Kconfig
@@ -168,6 +168,14 @@ config FB_DEFERRED_IO
 	bool
 	depends on FB
 
+config FB_DMA_HELPERS
+	bool
+	depends on FB
+	select FB_SYS_COPYAREA
+	select FB_SYS_FILLRECT
+	select FB_SYS_FOPS
+	select FB_SYS_IMAGEBLIT
+
 config FB_IO_HELPERS
 	bool
 	depends on FB
diff --git a/include/linux/fb.h b/include/linux/fb.h
index 1d5c13f34b09..1191a78c5289 100644
--- a/include/linux/fb.h
+++ b/include/linux/fb.h
@@ -594,6 +594,19 @@ extern ssize_t fb_sys_write(struct fb_info *info, const char __user *buf,
 	__FB_DEFAULT_SYS_OPS_DRAW, \
 	__FB_DEFAULT_SYS_OPS_MMAP
 
+/*
+ * Helpers for framebuffers in DMA-able memory
+ */
+
The comment for I/O memory helpers says:

/*
 * Initializes struct fb_ops for framebuffers in I/O memory.
 */

I think that would be good to have consistency between these two,
so something like:

/*
 * Initializes struct fb_ops for framebuffers in DMA-able memory.
 */
+#define __FB_DEFAULT_DMA_OPS_RDWR \
+	.fb_read	= fb_sys_read, \
+	.fb_write	= fb_sys_write
+
+#define __FB_DEFAULT_DMA_OPS_DRAW \
+	.fb_fillrect	= sys_fillrect, \
+	.fb_copyarea	= sys_copyarea, \
+	.fb_imageblit	= sys_imageblit
+
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>

-- 
Best regards,

Javier Martinez Canillas
Core Platforms
Red Hat
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