From f6b98994fa8246ac2a4b4043fa723b46344e3058 Mon Sep 17 00:00:00 2001
From: hanishkvc <hanishkvc@gmail.com>
Date: Sat, 27 Jun 2020 12:20:35 +0530
Subject: [PATCH 12/15] Added Intel Legacy Tile-Y layout conversion support

currently done in a simple dumb way. Two low hanging optimisations
that could be readily applied are

a) unrolling the inner for loop

b) using simd based 128bit loading and storing along with prefetch
hinting. TOTHINK|CHECK: Does memcpy already does this if situation
is right?!

Or I could even merge the two intel detiling logics into one, as
the semantic and flow is the same for both logics.
---
 libavfilter/vf_fbdetile.c | 41 ++++++++++++++++++++++++++++++++++++++-
 1 file changed, 40 insertions(+), 1 deletion(-)

diff --git a/libavfilter/vf_fbdetile.c b/libavfilter/vf_fbdetile.c
index 55c22007a3..8ac054e944 100644
--- a/libavfilter/vf_fbdetile.c
+++ b/libavfilter/vf_fbdetile.c
@@ -63,7 +63,7 @@ static av_cold int init(AVFilterContext *ctx)
     if (fbdetile->type == TYPE_INTELX) {
         fprintf(stderr,"INFO:fbdetile:init: Intel tile-x to linear\n");
     } else if (fbdetile->type == TYPE_INTELY) {
-        fprintf(stderr,"WARN:fbdetile:init: Intel tile-y to linear, not yet implemented\n");
+        fprintf(stderr,"INFO:fbdetile:init: Intel tile-y to linear\n");
     } else {
         fprintf(stderr,"DBUG:fbdetile:init: Unknown Tile format specified, shouldnt reach here\n");
     }
@@ -139,6 +139,41 @@ static void detile_intelx(AVFilterContext *ctx, int w, int h,
     }
 }
 
+static void detile_intely(AVFilterContext *ctx, int w, int h,
+                                uint8_t *dst, int dstLineSize,
+                          const uint8_t *src, int srcLineSize)
+{
+    // Offsets and LineSize are in bytes
+    int tileW = 4; // For a 32Bit / Pixel framebuffer, 16/4
+    int tileH = 32;
+
+    if (w*4 != srcLineSize) {
+        fprintf(stderr,"DBUG:fbdetile:intely: w%dxh%d, dL%d, sL%d\n", w, h, dstLineSize, srcLineSize);
+        fprintf(stderr,"ERRR:fbdetile:intely: dont support LineSize | Pitch going beyond width\n");
+    }
+    int sO = 0;
+    int dX = 0;
+    int dY = 0;
+    int nTRows = (w*h)/tileW;
+    int cTR = 0;
+    while (cTR < nTRows) {
+        int dO = dY*dstLineSize + dX*4;
+#ifdef DEBUG_FBTILE
+        fprintf(stderr,"DBUG:fbdetile:intely: dX%d dY%d, sO%d, dO%d\n", dX, dY, sO, dO);
+#endif
+        for (int k = 0; k < 32; k++) {
+            memcpy(dst+dO+k*dstLineSize, src+sO+k*16, 16);
+        }
+        dX += tileW;
+        if (dX >= w) {
+            dX = 0;
+            dY += 32;
+        }
+        sO = sO + 32*16;
+        cTR += 32;
+    }
+}
+
 static int filter_frame(AVFilterLink *inlink, AVFrame *in)
 {
     AVFilterContext *ctx = inlink->dst;
@@ -157,6 +192,10 @@ static int filter_frame(AVFilterLink *inlink, AVFrame *in)
         detile_intelx(ctx, fbdetile->width, fbdetile->height,
                       out->data[0], out->linesize[0],
                       in->data[0], in->linesize[0]);
+    } else if (fbdetile->type == TYPE_INTELY) {
+        detile_intely(ctx, fbdetile->width, fbdetile->height,
+                      out->data[0], out->linesize[0],
+                      in->data[0], in->linesize[0]);
     }
 
     av_frame_free(&in);
-- 
2.20.1