Add support for booting on t8012 (T2)

Address some peculiarities specific to T2:

- Reserved memory at top is very large, either 512 MB or 1536 MB, and only
lowest 512 MB is for OS use.

- Some ranges in /arm-io/ranges is not aligned to the page size. We align
them ourselves instead.

- On models with a screen, the framebuffer is extremely narrow at 60 pixels
in width, so add a smaller logo.

Signed-off-by: Nick Chan <towinchenmi@gmail.com>

Makefile

@@ -95,7 +95,7 @@ OBJECTS := \
 	afk.o \
 	aic.o \
 	asc.o \
-	bootlogo_128.o bootlogo_256.o \
+	bootlogo_48.o bootlogo_128.o bootlogo_256.o \
 	chainload.o \
 	chainload_asm.o \
 	chickens.o \

data/makelogo.sh

@@ -1,3 +1,4 @@
 #!/usr/bin/env sh
+convert bootlogo_48.png -background black -flatten -depth 8 rgba:bootlogo_48.bin
 convert bootlogo_128.png -background black -flatten -depth 8 rgba:bootlogo_128.bin
 convert bootlogo_256.png -background black -flatten -depth 8 rgba:bootlogo_256.bin

src/fb.c

@@ -44,12 +44,19 @@ static struct {
     bool active;
 } console;
 
+extern u8 _binary_build_bootlogo_48_bin_start[];
 extern u8 _binary_build_bootlogo_128_bin_start[];
 extern u8 _binary_build_bootlogo_256_bin_start[];
 
 extern u8 _binary_build_font_bin_start[];
 extern u8 _binary_build_font_retina_bin_start[];
 
+const struct image logo_48 = {
+    .ptr = (void *)_binary_build_bootlogo_48_bin_start,
+    .width = 48,
+    .height = 48,
+};
+
 const struct image logo_128 = {
     .ptr = (void *)_binary_build_bootlogo_128_bin_start,
     .width = 128,
@@ -409,7 +416,13 @@ void fb_init(bool clear)
     fb.ptr = malloc(fb.size);
     memcpy(fb.ptr, fb.hwptr, fb.size);
 
-    if (cur_boot_args.video.depth & FB_DEPTH_FLAG_RETINA) {
+    // This is the touchbar, make everything tiny
+    if (chip_id == T8012) {
+        logo = &logo_48;
+        console.font.ptr = _binary_build_font_bin_start;
+        console.font.width = 8;
+        console.font.height = 16;
+    } else if (cur_boot_args.video.depth & FB_DEPTH_FLAG_RETINA) {
         logo = &logo_256;
         console.font.ptr = _binary_build_font_retina_bin_start;
         console.font.width = 16;

src/memory.c

@@ -380,8 +380,11 @@ static void mmu_map_mmio(void)
         u64 bus = ranges[2] | ((u64)ranges[3] << 32);
         u64 size = ranges[4] | ((u64)ranges[5] << 32);
 
-        mmu_add_mapping(bus, bus, size, MAIR_IDX_DEVICE_nGnRnE, PERM_RW_EL0);
+        /* T2 is really stupid */
+        if (chip_id == T8012)
+            size = ALIGN_UP(size, PAGE_SIZE);
 
+        mmu_add_mapping(bus, bus, size, MAIR_IDX_DEVICE_nGnRnE, PERM_RW_EL0);
         ranges += 6;
     }
 }

src/startup.c

@@ -134,7 +134,23 @@ void dump_boot_args(struct boot_args *ba)
             break;
     }
     if (!mem_size_actual) {
-        mem_size_actual = ALIGN_UP(ba->phys_base + ba->mem_size - 0x800000000, BIT(30));
+        if (chip_id == T8012) {
+            int anode = adt_path_offset(adt, "/arm-io/mcc");
+
+            /*
+             * Lower 512 MB intented for OS use, upper 512 or 1536 MB is some sort
+             * of SSD cache. Cannot use dram-size, it may not exist in older firmwares
+             * This property is changed from 4 to 2 by iBoot on 1 GB RAM models.
+             */
+
+            u32 dcs_num_channels = 0;
+            if (anode > 0 && ADT_GETPROP(adt, anode, "dcs_num_channels", &dcs_num_channels) > 0)
+                mem_size_actual = dcs_num_channels * 0x20000000;
+            else
+                mem_size_actual = 0x40000000;
+        } else {
+            mem_size_actual = ALIGN_UP(ba->phys_base + ba->mem_size - 0x800000000, BIT(30));
+        }
         printf("Correcting mem_size_actual to 0x%lx\n", mem_size_actual);
     }
 }