display: Add logic to initialize the Mac Mini HDMI display

Signed-off-by: Hector Martin <marcan@marcan.st>

Makefile

@@ -62,6 +62,7 @@ OBJECTS := \
 	dart.o \
 	dcp.o \
 	dcp_iboot.o \
+	display.o \
 	exception.o exception_asm.o \
 	fb.o font.o font_retina.o \
 	gxf.o gxf_asm.o \

src/display.c

@@ -0,0 +1,179 @@
+/* SPDX-License-Identifier: MIT */
+
+#include "display.h"
+#include "assert.h"
+#include "dcp.h"
+#include "dcp_iboot.h"
+#include "utils.h"
+#include "xnuboot.h"
+
+#define COMPARE(a, b)                                                                              \
+    if ((a) > (b)) {                                                                               \
+        *best = modes[i];                                                                          \
+        continue;                                                                                  \
+    } else if ((a) < (b)) {                                                                        \
+        continue;                                                                                  \
+    }
+
+void display_choose_timing_mode(dcp_timing_mode_t *modes, int cnt, dcp_timing_mode_t *best)
+{
+    *best = modes[0];
+
+    for (int i = 1; i < cnt; i++) {
+        COMPARE(modes[i].valid, best->valid);
+        COMPARE(modes[i].width <= 1920, best->width <= 1920);
+        COMPARE(modes[i].fps <= 60 << 16, best->fps <= 60 << 16);
+        COMPARE(modes[i].width, best->width);
+        COMPARE(modes[i].height, best->height);
+        COMPARE(modes[i].fps, best->fps);
+    }
+
+    printf("display: timing mode: valid=%d %dx%d %d.%02d Hz\n", best->valid, best->width,
+           best->height, best->fps >> 16, (best->fps & 0xffff) * 99 / 0xffff);
+}
+
+void display_choose_color_mode(dcp_color_mode_t *modes, int cnt, dcp_color_mode_t *best)
+{
+    *best = modes[0];
+
+    for (int i = 1; i < cnt; i++) {
+        COMPARE(modes[i].valid, best->valid);
+        COMPARE(modes[i].bpp <= 32, best->bpp <= 32);
+        COMPARE(modes[i].bpp, best->bpp);
+        COMPARE(-modes[i].colorimetry, -best->colorimetry);
+        COMPARE(-modes[i].encoding, -best->encoding);
+        COMPARE(-modes[i].eotf, -best->eotf);
+    }
+
+    printf("display: color mode: valid=%d colorimetry=%d eotf=%d encoding=%d bpp=%d\n", best->valid,
+           best->colorimetry, best->eotf, best->encoding, best->bpp);
+}
+
+int display_configure(void)
+{
+    int ret = -1;
+
+    dcp_dev_t *dcp = dcp_init("/arm-io/dcp", "/arm-io/dart-dcp", "/arm-io/dart-disp0");
+    if (!dcp) {
+        printf("display: failed to initialize DCP\n");
+        return -1;
+    }
+
+    // Find the framebuffer DVA
+    u64 fb_dva = dart_search(dcp->dart_disp, (void *)cur_boot_args.video.base);
+    if (!fb_dva) {
+        printf("display: failed to find display DVA\n");
+        goto err_shutdown;
+    }
+
+    dcp_iboot_if_t *iboot = dcp_ib_init(dcp);
+    if (!iboot) {
+        printf("display: failed to initialize DCP iBoot interface\n");
+        goto err_shutdown;
+    }
+
+    // Power on
+    if ((ret = dcp_ib_set_power(iboot, true)) < 0) {
+        printf("display: failed to set power\n");
+        goto err_iboot;
+    }
+
+    // Detect if display is connected
+    int timing_cnt, color_cnt;
+    int hpd = ret = dcp_ib_get_hpd(iboot, &timing_cnt, &color_cnt);
+
+    if (hpd < 0) {
+        printf("display: failed to get display status\n");
+        goto err_iboot;
+    }
+
+    printf("display: connected:%d timing_cnt:%d color_cnt:%d\n", hpd, timing_cnt, color_cnt);
+
+    if (!hpd || !timing_cnt || !color_cnt)
+        goto bail;
+
+    // Find best modes
+    dcp_timing_mode_t *tmodes, tbest;
+    if ((ret = dcp_ib_get_timing_modes(iboot, &tmodes)) < 0) {
+        printf("display: failed to get timing modes\n");
+        goto err_iboot;
+    }
+    assert(ret == timing_cnt);
+    display_choose_timing_mode(tmodes, timing_cnt, &tbest);
+
+    dcp_color_mode_t *cmodes, cbest;
+    if ((ret = dcp_ib_get_color_modes(iboot, &cmodes)) < 0) {
+        printf("display: failed to get color modes\n");
+        goto err_iboot;
+    }
+    assert(ret == color_cnt);
+    display_choose_color_mode(cmodes, color_cnt, &cbest);
+
+    // Set mode
+    if ((ret = dcp_ib_set_mode(iboot, &tbest, &cbest)) < 0) {
+        printf("display: failed to set mode\n");
+        goto err_iboot;
+    }
+
+    // Swap!
+    int swap_id = ret = dcp_ib_swap_begin(iboot);
+    if (swap_id < 0) {
+        printf("display: failed to start swap\n");
+        goto err_iboot;
+    }
+
+    dcp_layer_t layer = {
+        .planes = {{
+            .addr = fb_dva,
+            .stride = tbest.width * 4,
+            .addr_format = ADDR_PLANAR,
+        }},
+        .plane_cnt = 1,
+        .width = tbest.width,
+        .height = tbest.height,
+        .surface_fmt = FMT_w30r,
+        .colorspace = 2,
+        .eotf = EOTF_GAMMA_SDR,
+        .transform = XFRM_NONE,
+    };
+
+    dcp_rect_t rect = {tbest.width, tbest.height, 0, 0};
+
+    if ((ret = dcp_ib_swap_set_layer(iboot, 0, &layer, &rect, &rect)) < 0) {
+        printf("display: failed to set layer\n");
+        goto err_iboot;
+    }
+
+    if ((ret = dcp_ib_swap_end(iboot)) < 0) {
+        printf("display: failed to complete swap\n");
+        goto err_iboot;
+    }
+
+    printf("display: swapped! (swap_id=%d)\n", swap_id);
+
+    cur_boot_args.video.stride = layer.planes[0].stride;
+    cur_boot_args.video.width = layer.width;
+    cur_boot_args.video.height = layer.height;
+    cur_boot_args.video.depth = 30;
+
+bail:
+    ret = 0;
+err_iboot:
+    dcp_ib_shutdown(iboot);
+err_shutdown:
+    dcp_shutdown(dcp);
+    return ret;
+}
+
+int display_init(void)
+{
+    if (cur_boot_args.video.width == 640 && cur_boot_args.video.height == 1136) {
+        printf("display: Dummy framebuffer found, initializing display\n");
+
+        return display_configure();
+    } else {
+        printf("display: Display is already initialized (%ldx%ld)\n", cur_boot_args.video.width,
+               cur_boot_args.video.height);
+        return 0;
+    }
+}

src/display.h

@@ -0,0 +1,8 @@
+/* SPDX-License-Identifier: MIT */
+
+#ifndef DISPLAY_H
+#define DISPLAY_H
+
+int display_init(void);
+
+#endif

src/main.c

@@ -5,6 +5,7 @@
 #include "adt.h"
 #include "aic.h"
 #include "cpufreq.h"
+#include "display.h"
 #include "exception.h"
 #include "fb.h"
 #include "gxf.h"
@@ -89,6 +90,7 @@ void m1n1_main(void)
     mmu_init();
 
 #ifdef USE_FB
+    display_init();
     fb_init();
     fb_display_logo();
 #endif