path: root/drivers/gpu/drm/drm_format_helper.c

// SPDX-License-Identifier: GPL-2.0 or MIT
/*
 * Copyright (C) 2016 Noralf Trønnes
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 */

#include <linux/io.h>
#include <linux/iosys-map.h>
#include <linux/module.h>
#include <linux/slab.h>

#include <drm/drm_device.h>
#include <drm/drm_format_helper.h>
#include <drm/drm_framebuffer.h>
#include <drm/drm_fourcc.h>
#include <drm/drm_print.h>
#include <drm/drm_rect.h>

static unsigned int clip_offset(const struct drm_rect *clip, unsigned int pitch, unsigned int cpp)
{
	return clip->y1 * pitch + clip->x1 * cpp;
}

/**
 * drm_fb_clip_offset - Returns the clipping rectangles byte-offset in a framebuffer
 * @pitch: Framebuffer line pitch in byte
 * @format: Framebuffer format
 * @clip: Clip rectangle
 *
 * Returns:
 * The byte offset of the clip rectangle's top-left corner within the framebuffer.
 */
unsigned int drm_fb_clip_offset(unsigned int pitch, const struct drm_format_info *format,
				const struct drm_rect *clip)
{
	return clip_offset(clip, pitch, format->cpp[0]);
}
EXPORT_SYMBOL(drm_fb_clip_offset);

/* TODO: Make this function work with multi-plane formats. */
static int __drm_fb_xfrm(void *dst, unsigned long dst_pitch, unsigned long dst_pixsize,
			 const void *vaddr, const struct drm_framebuffer *fb,
			 const struct drm_rect *clip, bool vaddr_cached_hint,
			 void (*xfrm_line)(void *dbuf, const void *sbuf, unsigned int npixels))
{
	unsigned long linepixels = drm_rect_width(clip);
	unsigned long lines = drm_rect_height(clip);
	size_t sbuf_len = linepixels * fb->format->cpp[0];
	void *stmp = NULL;
	unsigned long i;
	const void *sbuf;

	/*
	 * Some source buffers, such as DMA memory, use write-combine
	 * caching, so reads are uncached. Speed up access by fetching
	 * one line at a time.
	 */
	if (!vaddr_cached_hint) {
		stmp = kmalloc(sbuf_len, GFP_KERNEL);
		if (!stmp)
			return -ENOMEM;
	}

	if (!dst_pitch)
		dst_pitch = drm_rect_width(clip) * dst_pixsize;
	vaddr += clip_offset(clip, fb->pitches[0], fb->format->cpp[0]);

	for (i = 0; i < lines; ++i) {
		if (stmp)
			sbuf = memcpy(stmp, vaddr, sbuf_len);
		else
			sbuf = vaddr;
		xfrm_line(dst, sbuf, linepixels);
		vaddr += fb->pitches[0];
		dst += dst_pitch;
	}

	kfree(stmp);

	return 0;
}

/* TODO: Make this function work with multi-plane formats. */
static int __drm_fb_xfrm_toio(void __iomem *dst, unsigned long dst_pitch, unsigned long dst_pixsize,
			      const void *vaddr, const struct drm_framebuffer *fb,
			      const struct drm_rect *clip, bool vaddr_cached_hint,
			      void (*xfrm_line)(void *dbuf, const void *sbuf, unsigned int npixels))
{
	unsigned long linepixels = drm_rect_width(clip);
	unsigned long lines = drm_rect_height(clip);
	size_t dbuf_len = linepixels * dst_pixsize;
	size_t stmp_off = round_up(dbuf_len, ARCH_KMALLOC_MINALIGN); /* for sbuf alignment */
	size_t sbuf_len = linepixels * fb->format->cpp[0];
	void *stmp = NULL;
	unsigned long i;
	const void *sbuf;
	void *dbuf;

	if (vaddr_cached_hint) {
		dbuf = kmalloc(dbuf_len, GFP_KERNEL);
	} else {
		dbuf = kmalloc(stmp_off + sbuf_len, GFP_KERNEL);
		stmp = dbuf