fbdev: c2p/atafb - Add support for Atari interleaved bitplanes

The c2p() for normal bitplanes is not suitable for interleaved bitplanes with
2 bytes of interleave, causing a garbled penguin logo. Add c2p_iplan2().

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>

1 files changed, 153 insertions, 0 deletions

diff --git a/drivers/video/c2p_iplan2.c b/drivers/video/c2p_iplan2.c
new file mode 100644
index 000000000000..19156dc6158c
--- /dev/null
+++ b/drivers/video/c2p_iplan2.c
@@ -0,0 +1,153 @@
+/*
+ *  Fast C2P (Chunky-to-Planar) Conversion
+ *
+ *  Copyright (C) 2003-2008 Geert Uytterhoeven
+ *
+ *  This file is subject to the terms and conditions of the GNU General Public
+ *  License. See the file COPYING in the main directory of this archive
+ *  for more details.
+ */
+
+#include <linux/module.h>
+#include <linux/string.h>
+
+#include <asm/unaligned.h>
+
+#include "c2p.h"
+#include "c2p_core.h"
+
+
+    /*
+     *  Perform a full C2P step on 16 8-bit pixels, stored in 4 32-bit words
+     *  containing
+     *    - 16 8-bit chunky pixels on input
+     *    - permutated planar data (2 planes per 32-bit word) on output
+     */
+
+static void c2p_16x8(u32 d[4])
+{
+	transp4(d, 8, 2);
+	transp4(d, 1, 2);
+	transp4x(d, 16, 2);
+	transp4x(d, 2, 2);
+	transp4(d, 4, 1);
+}
+
+
+    /*
+     *  Array containing the permutation indices of the planar data after c2p
+     */
+
+static const int perm_c2p_16x8[4] = { 1, 3, 0, 2 };
+
+
+    /*
+     *  Store a full block of iplan2 data after c2p conversion
+     */
+
+static inline void store_iplan2(void *dst, u32 bpp, u32 d[4])
+{
+	int i;
+
+	for (i = 0; i < bpp/2; i++, dst += 4)
+		put_unaligned_be32(d[perm_c2p_16x8[i]], dst);
+}
+
+
+    /*
+     *  Store a partial block of iplan2 data after c2p conversion
+     */
+
+static inline void store_iplan2_masked(void *dst, u32 bpp, u32 d[4], u32 mask)
+{
+	int i;
+
+	for (i = 0; i < bpp/2; i++, dst += 4)
+		put_unaligned_be32(comp(d[perm_c2p_16x8[i]],
+					get_unaligned_be32(dst), mask),
+				   dst);
+}
+
+
+    /*
+     *  c2p_iplan2 - Copy 8-bit chunky image data to an interleaved planar
+     *  frame buffer with 2 bytes of interleave
+     *  @dst: Starting address of the planar frame buffer
+     *  @dx: Horizontal destination offset (in pixels)
+     *  @dy: Vertical destination offset (in pixels)
+     *  @width: Image width (in pixels)
+     *  @height: Image height (in pixels)
+     *  @dst_nextline: Frame buffer offset to the next line (in bytes)
+     *  @src_nextline: Image offset to the next line (in bytes)
+     *  @bpp: Bits per pixel of the planar frame buffer (2, 4, or 8)
+     */
+
+void c2p_iplan2(void *dst, const void *src, u32 dx, u32 dy, u32 width,
+		u32 height, u32 dst_nextline, u32 src_nextline, u32 bpp)
+{
+	union {
+		u8 pixels[16];
+		u32 words[4];
+	} d;
+	u32 dst_idx, first, last, w;
+	const u8 *c;
+	void *p;
+
+	dst += dy*dst_nextline+(dx & ~15)*bpp;
+	dst_idx = dx % 16;
+	first = 0xffffU >> dst_idx;
+	first |= first << 16;
+	last = 0xffffU ^ (0xffffU >> ((dst_idx+width) % 16));
+	last |= last << 16;
+	while (height--) {
+		c = src;
+		p = dst;
+		w = width;
+		if (dst_idx+width <= 16) {
+			/* Single destination word */
+			first &= last;
+			memset(d.pixels, 0, sizeof(d));
+			memcpy(d.pixels+dst_idx, c, width);
+			c += width;
+			c2p_16x8(d.words);
+			store_iplan2_masked(p, bpp, d.words, first);
+			p += bpp*2;
+		} else {
+			/* Multiple destination words */
+			w = width;
+			/* Leading bits */
+			if (dst_idx) {
+				w = 16 - dst_idx;
+				memset(d.pixels, 0, dst_idx);
+				memcpy(d.pixels+dst_idx, c, w);
+				c += w;
+				c2p_16x8(d.words);
+				store_iplan2_masked(p, bpp, d.words, first);
+				p += bpp*2;
+				w = width-w;
+			}
+			/* Main chunk */
+			while (w >= 16) {
+				memcpy(d.pixels, c, 16);
+				c += 16;
+				c2p_16x8(d.words);
+				store_iplan2(p, bpp, d.words);
+				p += bpp*2;
+				w -= 16;
+			}
+			/* Trailing bits */
+			w %= 16;
+			if (w > 0) {
+				memcpy(d.pixels, c, w);
+				memset(d.pixels+w, 0, 16-w);
+				c2p_16x8(d.words);
+				store_iplan2_masked(p, bpp, d.words, last);
+			}
+		}
+		src += src_nextline;
+		dst += dst_nextline;
+	}
+}
+EXPORT_SYMBOL_GPL(c2p_iplan2);
+
+MODULE_LICENSE("GPL");