display: contain all display init logic within display.c

Display handling was spread across main.c, utils.c and display.c
with the addition of iDevice support. Condense all of this functionality
into display.c.

This also fixes a regression introduced in 869d2ae ("Skip over features
unsupported in A7-A11 SoCs."), which caused devices using dcpext to skip DCP
initialisation.

Signed-off-by: James Calligeros <jcalligeros99@gmail.com>

Author: chadmed

src/display.c

@@ -30,6 +30,7 @@ static dcp_dev_t *dcp;
 static dcp_iboot_if_t *iboot;
 static u64 fb_dva;
 static u64 fb_size;
+bool has_dcp;
 bool display_is_external;
 bool display_is_dptx;
 bool display_needs_power_cycle;
@@ -244,14 +245,23 @@ static uintptr_t display_map_fb(uintptr_t iova, u64 paddr, u64 size)
 
 const display_config_t *display_get_config(void)
 {
+    const display_config_t *conf = NULL;
+
     if (adt_is_compatible(adt, 0, "J473AP"))
-        return &display_config_m2;
+        conf = &display_config_m2;
     else if (adt_is_compatible(adt, 0, "J474sAP") || adt_is_compatible(adt, 0, "J475cAP"))
-        return &display_config_m2_pro_max;
+        conf = &display_config_m2_pro_max;
     else if (adt_is_compatible(adt, 0, "J180dAP") || adt_is_compatible(adt, 0, "J475dAP"))
-        return &display_config_m2_ultra;
+        conf = &display_config_m2_ultra;
     else
-        return &display_config_m1;
+        conf = &display_config_m1;
+
+    has_dcp = !!adt_path_offset(adt, conf->dcp);
+    if (!has_dcp) {
+        return NULL;
+    }
+
+    return conf;
 }
 
 int display_start_dcp(void)
@@ -264,13 +274,13 @@ int display_start_dcp(void)
     return 0;
 #endif
 
+    const display_config_t *disp_cfg = display_get_config();
+
     if (!has_dcp) {
-        printf("display: DCP not present\n");
+        printf("display: device has no DCP. Display will not be initialised.\n");
         return -1;
     }
 
-    const display_config_t *disp_cfg = display_get_config();
-
     display_is_dptx = !!disp_cfg->dptx_phy[0];
 
     dcp = dcp_init(disp_cfg);
@@ -655,6 +665,10 @@ int display_init(void)
 
 void display_shutdown(dcp_shutdown_mode mode)
 {
+    /* We have no DCP, so just exit */
+    if (!has_dcp)
+        return;
+
     if (iboot) {
         dcp_ib_shutdown(iboot);
         switch (mode) {

src/main.c

@@ -51,7 +51,6 @@ void get_device_info(void)
         printf("  Target: %s\n", target);
 
     is_mac = !!strstr(model, "Mac");
-    has_dcp = adt_path_offset(adt, "/arm-io/dcp") > 0;
 
     int chosen = adt_path_offset(adt, "/chosen");
     if (chosen > 0) {
@@ -165,8 +164,7 @@ void m1n1_main(void)
     display_init();
     // Kick DCP to sleep, so dodgy monitors which cause reconnect cycles don't cause us to lose the
     // framebuffer.
-    if (has_dcp)
-        display_shutdown(DCP_SLEEP_IF_EXTERNAL);
+    display_shutdown(DCP_SLEEP_IF_EXTERNAL);
     // On idevice we need to always clear, because otherwise it looks scuffed on white devices
     fb_init(!is_mac);
     fb_display_logo();

src/utils.c

@@ -12,7 +12,7 @@
 #include "vsprintf.h"
 #include "xnuboot.h"
 
-bool is_mac, has_dcp;
+bool is_mac;
 
 static char ascii(char s)
 {

src/utils.h

@@ -464,7 +464,7 @@ struct vector_args {
 
 extern u32 board_id, chip_id;
 
-extern bool is_mac, has_dcp;
+extern bool is_mac;
 extern bool cpufeat_actlr_el2, cpufeat_fast_ipi, cpufeat_mmu_sprr;
 extern bool cpufeat_global_sleep, cpufeat_workaround_cyclone_cache;