[PATCH 4/7] fbdev: c2p - Cleanups

Geert Uytterhoeven
2009-01-04T11:47:10Z

- Improve comments and naming
- Convert macros to static inline functions
- Remove superfluous `break' after `return'
- Make sure we get a build-time error (undefined reference to
'c2p_unsupported') in case of future misuse
- Replace `unsigned long' by `u32' in comp(), as that's what all callers use
- Use {get,put}_unaligned_be32() in store_planar{,_masked}()
- Use void * for arbitrary pointers
- Use a union to represent pixels/words, to avoid casts

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
---
drivers/video/c2p.c | 181 +++++++++++++++++++++++++++------------------------
drivers/video/c2p.h | 6 +-
2 files changed, 99 insertions(+), 88 deletions(-)

diff --git a/drivers/video/c2p.c b/drivers/video/c2p.c
index f102b57..c170fff 100644
--- a/drivers/video/c2p.c
+++ b/drivers/video/c2p.c
@@ -1,7 +1,7 @@
/*
* Fast C2P (Chunky-to-Planar) Conversion
*
- * Copyright (C) 2003 Geert Uytterhoeven
+ * Copyright (C) 2003-2008 Geert Uytterhoeven
*
* NOTES:
* - This code was inspired by Scout's C2P tutorial
@@ -14,6 +14,9 @@

#include <linux/module.h>
#include <linux/string.h>
+
+#include <asm/unaligned.h>
+
#include "c2p.h"

@@ -21,97 +24,100 @@
* Basic transpose step
*/

-#define _transp(d, i1, i2, shift, mask) \
- do { \
- u32 t = (d[i1] ^ (d[i2] >> shift)) & mask; \
- d[i1] ^= t; \
- d[i2] ^= t << shift; \
- } while (0)
+static inline void _transp(u32 d[], unsigned int i1, unsigned int i2,
+ unsigned int shift, u32 mask)
+{
+ u32 t = (d[i1] ^ (d[i2] >> shift)) & mask;
+
+ d[i1] ^= t;
+ d[i2] ^= t << shift;
+}

-static inline u32 get_mask(int n)
+extern void c2p_unsupported(void);
+
+static inline u32 get_mask(unsigned int n)
{
switch (n) {
case 1:
return 0x55555555;
- break;

case 2:
return 0x33333333;
- break;

case 4:
return 0x0f0f0f0f;
- break;

case 8:
return 0x00ff00ff;
- break;

case 16:
return 0x0000ffff;
- break;
}
+
+ c2p_unsupported();
return 0;
}

-#define transp_nx1(d, n) \
- do { \
- u32 mask = get_mask(n); \
- /* First block */ \
- _transp(d, 0, 1, n, mask); \
- /* Second block */ \
- _transp(d, 2, 3, n, mask); \
- /* Third block */ \
- _transp(d, 4, 5, n, mask); \
- /* Fourth block */ \
- _transp(d, 6, 7, n, mask); \
- } while (0)
-
-#define transp_nx2(d, n) \
- do { \
- u32 mask = get_mask(n); \
- /* First block */ \
- _transp(d, 0, 2, n, mask); \
- _transp(d, 1, 3, n, mask); \
- /* Second block */ \
- _transp(d, 4, 6, n, mask); \
- _transp(d, 5, 7, n, mask); \
- } while (0)
-
-#define transp_nx4(d, n) \
- do { \
- u32 mask = get_mask(n); \
- _transp(d, 0, 4, n, mask); \
- _transp(d, 1, 5, n, mask); \
- _transp(d, 2, 6, n, mask); \
- _transp(d, 3, 7, n, mask); \
- } while (0)
-
-#define transp(d, n, m) transp_nx ## m(d, n)
+static inline void transp8(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);
+ /* Third n x 1 block */
+ _transp(d, 4, 5, n, mask);
+ /* Fourth n x 1 block */
+ _transp(d, 6, 7, n, mask);
+ return;
+
+ case 2:
+ /* First n x 2 block */
+ _transp(d, 0, 2, n, mask);
+ _transp(d, 1, 3, n, mask);
+ /* Second n x 2 block */
+ _transp(d, 4, 6, n, mask);
+ _transp(d, 5, 7, n, mask);
+ return;
+
+ case 4:
+ /* Single n x 4 block */
+ _transp(d, 0, 4, n, mask);
+ _transp(d, 1, 5, n, mask);
+ _transp(d, 2, 6, n, mask);
+ _transp(d, 3, 7, n, mask);
+ return;
+ }
+
+ c2p_unsupported();
+}

/*
* Perform a full C2P step on 32 8-bit pixels, stored in 8 32-bit words
* containing
* - 32 8-bit chunky pixels on input
- * - permuted planar data on output
+ * - permutated planar data (1 plane per 32-bit word) on output
*/

-static void c2p_8bpp(u32 d[8])
+static void c2p_32x8(u32 d[8])
{
- transp(d, 16, 4);
- transp(d, 8, 2);
- transp(d, 4, 1);
- transp(d, 2, 4);
- transp(d, 1, 2);
+ transp8(d, 16, 4);
+ transp8(d, 8, 2);
+ transp8(d, 4, 1);
+ transp8(d, 2, 4);
+ transp8(d, 1, 2);
}

/*
- * Array containing the permution indices of the planar data after c2p
+ * Array containing the permutation indices of the planar data after c2p
*/

-static const int perm_c2p_8bpp[8] = { 7, 5, 3, 1, 6, 4, 2, 0 };
+static const int perm_c2p_32x8[8] = { 7, 5, 3, 1, 6, 4, 2, 0 };

/*
@@ -119,8 +125,7 @@ static const int perm_c2p_8bpp[8] = { 7, 5, 3, 1, 6, 4, 2, 0 };
* This is equivalent to (a & mask) | (b & ~mask)
*/

-static inline unsigned long comp(unsigned long a, unsigned long b,
- unsigned long mask)
+static inline u32 comp(u32 a, u32 b, u32 mask)
{
return ((a ^ b) & mask) ^ b;
}
@@ -130,12 +135,12 @@ static inline unsigned long comp(unsigned long a, unsigned long b,
* Store a full block of planar data after c2p conversion
*/

-static inline void store_planar(char *dst, u32 dst_inc, u32 bpp, u32 d[8])
+static inline void store_planar(void *dst, u32 dst_inc, u32 bpp, u32 d[8])
{
int i;

for (i = 0; i < bpp; i++, dst += dst_inc)
- *(u32 *)dst = d[perm_c2p_8bpp[i]];
+ put_unaligned_be32(d[perm_c2p_32x8[i]], dst);
}

@@ -143,13 +148,15 @@ static inline void store_planar(char *dst, u32 dst_inc, u32 bpp, u32 d[8])
* Store a partial block of planar data after c2p conversion
*/

-static inline void store_planar_masked(char *dst, u32 dst_inc, u32 bpp,
+static inline void store_planar_masked(void *dst, u32 dst_inc, u32 bpp,
u32 d[8], u32 mask)
{
int i;

for (i = 0; i < bpp; i++, dst += dst_inc)
- *(u32 *)dst = comp(d[perm_c2p_8bpp[i]], *(u32 *)dst, mask);
+ put_unaligned_be32(comp(d[perm_c2p_32x8[i]],
+ get_unaligned_be32(dst), mask),
+ dst);
}

@@ -166,18 +173,21 @@ static inline void store_planar_masked(char *dst, u32 dst_inc, u32 bpp,
* @bpp: Bits per pixel of the planar frame buffer (1-8)
*/

-void c2p(u8 *dst, const u8 *src, u32 dx, u32 dy, u32 width, u32 height,
+void c2p(void *dst, const void *src, u32 dx, u32 dy, u32 width, u32 height,
u32 dst_nextline, u32 dst_nextplane, u32 src_nextline, u32 bpp)
{
- int dst_idx;
- u32 d[8], first, last, w;
+ union {
+ u8 pixels[32];
+ u32 words[8];
+ } d;
+ u32 dst_idx, first, last, w;
const u8 *c;
- u8 *p;
+ void *p;

dst += dy*dst_nextline+(dx & ~31);
dst_idx = dx % 32;
- first = ~0UL >> dst_idx;
- last = ~(~0UL >> ((dst_idx+width) % 32));
+ first = 0xffffffffU >> dst_idx;
+ last = ~(0xffffffffU >> ((dst_idx+width) % 32));
while (height--) {
c = src;
p = dst;
@@ -185,11 +195,12 @@ void c2p(u8 *dst, const u8 *src, u32 dx, u32 dy, u32 width, u32 height,
if (dst_idx+width <= 32) {
/* Single destination word */
first &= last;
- memset(d, 0, sizeof(d));
- memcpy((u8 *)d+dst_idx, c, width);
+ memset(d.pixels, 0, sizeof(d));
+ memcpy(d.pixels+dst_idx, c, width);
c += width;
- c2p_8bpp(d);
- store_planar_masked(p, dst_nextplane, bpp, d, first);
+ c2p_32x8(d.words);
+ store_planar_masked(p, dst_nextplane, bpp, d.words,
+ first);
p += 4;
} else {
/* Multiple destination words */
@@ -197,32 +208,32 @@ void c2p(u8 *dst, const u8 *src, u32 dx, u32 dy, u32 width, u32 height,
/* Leading bits */
if (dst_idx) {
w = 32 - dst_idx;
- memset(d, 0, dst_idx);
- memcpy((u8 *)d+dst_idx, c, w);
+ memset(d.pixels, 0, dst_idx);
+ memcpy(d.pixels+dst_idx, c, w);
c += w;
- c2p_8bpp(d);
- store_planar_masked(p, dst_nextplane, bpp, d,
- first);
+ c2p_32x8(d.words);
+ store_planar_masked(p, dst_nextplane, bpp,
+ d.words, first);
p += 4;
w = width-w;
}
/* Main chunk */
while (w >= 32) {
- memcpy(d, c, 32);
+ memcpy(d.pixels, c, 32);
c += 32;
- c2p_8bpp(d);
- store_planar(p, dst_nextplane, bpp, d);
+ c2p_32x8(d.words);
+ store_planar(p, dst_nextplane, bpp, d.words);
p += 4;
w -= 32;
}
/* Trailing bits */
w %= 32;
if (w > 0) {
- memcpy(d, c, w);
- memset((u8 *)d+w, 0, 32-w);
- c2p_8bpp(d);
- store_planar_masked(p, dst_nextplane, bpp, d,
- last);
+ memcpy(d.pixels, c, w);
+ memset(d.pixels+w, 0, 32-w);
+ c2p_32x8(d.words);
+ store_planar_masked(p, dst_nextplane, bpp,
+ d.words, last);
}
}
src += src_nextline;
diff --git a/drivers/video/c2p.h b/drivers/video/c2p.h
index c77cbf1..daafd87 100644
--- a/drivers/video/c2p.h
+++ b/drivers/video/c2p.h
@@ -10,7 +10,7 @@

#include <linux/types.h>

-extern void c2p(u8 *dst, const u8 *src, u32 dx, u32 dy, u32 width, u32 height,
- u32 dst_nextline, u32 dst_nextplane, u32 src_nextline,
- u32 bpp);
+extern void c2p(void *dst, const void *src, u32 dx, u32 dy, u32 width,
+ u32 height, u32 dst_nextline, u32 dst_nextplane,
+ u32 src_nextline, u32 bpp);

--
1.5.6.5