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>
diff --git a/drivers/video/c2p_iplan2.c b/drivers/video/c2p_iplan2.c
new file mode 100644
index 0000000..19156dc
--- /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");