Pi Firmware: chars_per_line is always in units of 8 pixels, regardless of frame buffer bit depth

Change-Id: I66f6d1e2ffbd0421a976e5f341b0a70f6a215313

src/capture_line_default_4bpp.S

@@ -9,7 +9,7 @@
 
 // The capture line function is provided the following:
 //   r0 = pointer to current line in frame buffer
-//   r1 = number of complete psync cycles to capture (=param_chars_per_line)
+//   r1 = number of 8-pixel blocks to capture (=param_chars_per_line)
 //   r2 = frame buffer line pitch in bytes (=param_fb_pitch)
 //   r3 = flags register
 //   r4 = GPLEV0 constant

src/capture_line_default_8bpp.S

@@ -26,7 +26,7 @@
 
 // The capture line function is provided the following:
 //   r0 = pointer to current line in frame buffer
-//   r1 = number of complete psync cycles to capture (=param_chars_per_line)
+//   r1 = number of 8-pixel blocks to capture (=param_chars_per_line)
 //   r2 = frame buffer line pitch in bytes (=param_fb_pitch)
 //   r3 = flags register
 //   r4 = GPLEV0 constant
@@ -61,8 +61,6 @@ loop:
         str    r0, [r12, r2]
 #endif
         str    r10, [r12], #4
-        subs   r6, r6, #1
-        beq    exit
 
         WAIT_FOR_PSYNC_01
 
@@ -82,6 +80,7 @@ loop:
         str    r0, [r12, r2]
 #endif
         str    r10, [r12], #4
+
         subs   r6, r6, #1
         bne    loop
 

src/capture_line_mode7_4bpp.S

@@ -9,7 +9,7 @@
 
 // The capture line function is provided the following:
 //   r0 = pointer to current line in frame buffer
-//   r1 = number of complete psync cycles to capture (=param_chars_per_line)
+//   r1 = number of 8-pixel blocks to capture (=param_chars_per_line)
 //   r2 = frame buffer line pitch in bytes (=param_fb_pitch)
 //   r3 = flags register
 //   r4 = GPLEV0 constant

src/rgb_to_fb.S

@@ -156,11 +156,9 @@ rgb_to_fb:
         ldr    r2, [r0, #O_FB_BASE]
         str    r2, param_framebuffer0
 
-        // Sanity check chars_per_line <= fb_width * fb_bpp / 32
+        // Sanity check chars_per_line <= fb_width / 8
         ldr    r3, param_fb_width
-        ldr    r2, param_fb_bpp
-        mul    r3, r3, r2
-        lsr    r3, r3, #5
+        lsr    r3, r3, #3
         ldr    r2, param_chars_per_line
         cmp    r2, r3
         strgt  r3, param_chars_per_line
@@ -227,7 +225,7 @@ frame:
         // Working registers while frame is being captured
         //
         //  r0 = scratch register
-        //  r1 = number of complete psync cycles to capture (=param_chars_per_line)
+        //  r1 = number of 8-pixel blocks to capture (=param_chars_per_line)
         //  r2 = frame buffer line pitch in bytes (=param_fb_pitch)
         //  r3 = flags register
         //  r4 = GPLEV0 constant