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, 47 insertions, 0 deletions

diff --git a/drivers/video/c2p_core.h b/drivers/video/c2p_core.h
index 3573cf723e43..e1035a865fb9 100644
--- a/drivers/video/c2p_core.h
+++ b/drivers/video/c2p_core.h
@@ -96,6 +96,53 @@ static inline void transp8(u32 d[], unsigned int n, unsigned int m)
 
 
     /*
+     *  Transpose operations on 4 32-bit words
+     */
+
+static inline void transp4(u32 d[], unsigned int n, unsigned int m)
+{
+	u32 mask = get_mask(n);
+
+	switch (m) {
+	case 1:
+		/* First n x 1 block */
+		_transp(d, 0, 1, n, mask);
+		/* Second n x 1 block */
+		_transp(d, 2, 3, n, mask);
+		return;
+
+	case 2:
+		/* Single n x 2 block */
+		_transp(d, 0, 2, n, mask);
+		_transp(d, 1, 3, n, mask);
+		return;
+	}
+
+	c2p_unsupported();
+}
+
+
+    /*
+     *  Transpose operations on 4 32-bit words (reverse order)
+     */
+
+static inline void transp4x(u32 d[], unsigned int n, unsigned int m)
+{
+	u32 mask = get_mask(n);
+
+	switch (m) {
+	case 2:
+		/* Single n x 2 block */
+		_transp(d, 2, 0, n, mask);
+		_transp(d, 3, 1, n, mask);
+		return;
+	}
+
+	c2p_unsupported();
+}
+
+
+    /*
      *  Compose two values, using a bitmask as decision value
      *  This is equivalent to (a & mask) | (b & ~mask)
      */