From f5a51b0671fa81d530b00e93671cd05ce3bbf27e Mon Sep 17 00:00:00 2001
From: cepetr <petr@cerninovi.cz>
Date: Wed, 26 Feb 2025 10:05:05 +0100
Subject: [PATCH] feat(core): enable hw decoding of grayscale JPEGs

[no changelog]
---
 core/embed/gfx/bitblt/dma2d_bitblt.h       |  2 +
 core/embed/gfx/bitblt/stm32/dma2d_bitblt.c | 59 ++++++++++++++++++++++
 core/embed/gfx/jpegdec/stm32u5/jpegdec.c   |  3 +-
 3 files changed, 63 insertions(+), 1 deletion(-)

diff --git a/core/embed/gfx/bitblt/dma2d_bitblt.h b/core/embed/gfx/bitblt/dma2d_bitblt.h
index e98263301b..730e8e10eb 100644
--- a/core/embed/gfx/bitblt/dma2d_bitblt.h
+++ b/core/embed/gfx/bitblt/dma2d_bitblt.h
@@ -44,6 +44,7 @@ bool dma2d_rgb565_blend_mono8(const gfx_bitblt_t* bb);
 
 bool dma2d_rgba8888_fill(const gfx_bitblt_t* bb);
 bool dma2d_rgba8888_copy_mono4(const gfx_bitblt_t* bb);
+bool dma2d_rgba8888_copy_mono8(const gfx_bitblt_t* bb);
 bool dma2d_rgba8888_copy_rgb565(const gfx_bitblt_t* bb);
 bool dma2d_rgba8888_copy_rgba8888(const gfx_bitblt_t* bb);
 bool dma2d_rgba8888_blend_mono4(const gfx_bitblt_t* bb);
@@ -53,4 +54,5 @@ bool dma2d_rgba8888_blend_mono8(const gfx_bitblt_t* bb);
 bool dma2d_rgba8888_copy_ycbcr420(const gfx_bitblt_t* bb);
 bool dma2d_rgba8888_copy_ycbcr422(const gfx_bitblt_t* bb);
 bool dma2d_rgba8888_copy_ycbcr444(const gfx_bitblt_t* bb);
+bool dma2d_rgba8888_copy_y(const gfx_bitblt_t* bb);
 #endif
diff --git a/core/embed/gfx/bitblt/stm32/dma2d_bitblt.c b/core/embed/gfx/bitblt/stm32/dma2d_bitblt.c
index 86c09423df..1cf5603d92 100644
--- a/core/embed/gfx/bitblt/stm32/dma2d_bitblt.c
+++ b/core/embed/gfx/bitblt/stm32/dma2d_bitblt.c
@@ -763,6 +763,37 @@ bool dma2d_rgba8888_blend_mono8(const gfx_bitblt_t* bb) {
   return true;
 }
 
+bool dma2d_rgba8888_copy_mono8(const gfx_bitblt_t* bb) {
+  dma2d_driver_t* drv = &g_dma2d_driver;
+
+  if (!drv->initialized) {
+    return false;
+  }
+
+  dma2d_wait();
+
+  if (!dma2d_accessible(bb->dst_row) || !dma2d_accessible(bb->src_row)) {
+    return false;
+  }
+
+  drv->handle.Init.ColorMode = DMA2D_OUTPUT_ARGB8888;
+  drv->handle.Init.Mode = DMA2D_M2M_PFC;
+  drv->handle.Init.OutputOffset = bb->dst_stride / sizeof(uint32_t) - bb->width;
+  HAL_DMA2D_Init(&drv->handle);
+
+  drv->handle.LayerCfg[1].InputColorMode = DMA2D_INPUT_A8;
+  drv->handle.LayerCfg[1].InputOffset = bb->src_stride - bb->width;
+  drv->handle.LayerCfg[1].AlphaMode = 0;
+  drv->handle.LayerCfg[1].InputAlpha = gfx_color_to_color32(bb->src_fg);
+  HAL_DMA2D_ConfigLayer(&drv->handle, 1);
+
+  HAL_DMA2D_Start(&drv->handle, (uint32_t)bb->src_row + bb->src_x,
+                  (uint32_t)bb->dst_row + bb->dst_x * sizeof(uint32_t),
+                  bb->width, bb->height);
+
+  return true;
+}
+
 bool dma2d_rgba8888_copy_rgba8888(const gfx_bitblt_t* bb) {
   dma2d_driver_t* drv = &g_dma2d_driver;
 
@@ -848,6 +879,34 @@ bool dma2d_rgba8888_copy_ycbcr444(const gfx_bitblt_t* bb) {
   return dma2d_rgba8888_copy_ycbcr(bb, DMA2D_NO_CSS);
 }
 
+bool dma2d_rgba8888_copy_y(const gfx_bitblt_t* bb) {
+  gfx_bitblt_t bb_copy = *bb;
+
+  if (bb->height % 8 != 0 || bb->width % 8 != 0) {
+    return false;
+  }
+
+  // src cotains only Y channel organized in 8x8 blocks
+
+  bb_copy.height = 8;
+  bb_copy.width = 8;
+  bb_copy.src_stride = 8;
+  bb_copy.src_fg = gfx_color_rgb(255, 255, 255);
+
+  for (uint16_t y = 0; y < bb->height; y += 8) {
+    bb_copy.dst_x = 0;
+    for (uint16_t x = 0; x < bb->width; x += 8) {
+      if (!dma2d_rgba8888_copy_mono8(&bb_copy)) {
+        return false;
+      }
+      bb_copy.dst_x += 8;
+      bb_copy.src_row = (uint8_t*)bb_copy.src_row + 64;
+    }
+    bb_copy.dst_y += 8;
+  }
+  return true;
+}
+
 // Temporary hack to invalidate CLUT cache used in jpeg decoder.
 // This function should be removed in the future with DMA2D syscalls.
 void dma2d_invalidate_clut(void) {
diff --git a/core/embed/gfx/jpegdec/stm32u5/jpegdec.c b/core/embed/gfx/jpegdec/stm32u5/jpegdec.c
index 18f30c4474..fa75f85f8b 100644
--- a/core/embed/gfx/jpegdec/stm32u5/jpegdec.c
+++ b/core/embed/gfx/jpegdec/stm32u5/jpegdec.c
@@ -456,7 +456,8 @@ bool jpegdec_get_slice_rgba8888(uint32_t *rgba8888, jpegdec_slice_t *slice) {
       result = dma2d_rgba8888_copy_ycbcr444(&bb);
       break;
     case JPEGDEC_IMAGE_GRAYSCALE:
-      // Conversion from grayscale to RGBA8888 is not supported
+      result = dma2d_rgba8888_copy_y(&bb);
+      break;
     default:
       result = false;
       break;