Added touchscreen calibration from NVRAM (thanks @wolfvak)

arm9/source/common/touchcal.c

@@ -1,15 +1,34 @@
 #include "touchcal.h"
 #include "ui.h"
 #include "hid.h"
+#include "crc16.h"
+#include "spiflash.h"
 
 
-bool ShowCalibrationDialog(void)
+static const HID_CalibrationData default_calib = {
+    .screen_x = 0,
+    .screen_y = 0,
+    .ts_raw = 0
+    // ^ wrong: in my console it's 0x780086
+    // but this is very much console dependent
+    // so it's better to go with a sane default
+};
+
+
+static bool SetCalibrationDefaults(void)
+{
+	// Hardcoding this isn't ideal but it's better than
+    // leaving the system without any state to work with
+    return HID_SetCalibrationData(&default_calib, 1, SCREEN_WIDTH_BOT, SCREEN_HEIGHT);
+}
+
+bool ShowTouchCalibrationDialog(void)
 {
     static const u32 dot_positions[][2] = {
         {16, 16},
-        {320 - 16, 240 - 16},
-        {16, 240 - 16},
-        {320 - 16, 16},
+        {SCREEN_WIDTH_BOT - 16, SCREEN_HEIGHT - 16},
+        {16, SCREEN_HEIGHT - 16},
+        {SCREEN_WIDTH_BOT - 16, 16},
     };
 
     HID_CalibrationData calibrations[countof(dot_positions)];
@@ -23,6 +42,9 @@ bool ShowCalibrationDialog(void)
     DrawStringCenter(BOT_SCREEN, COLOR_STD_FONT, COLOR_STD_BG,
         "Touch the red crosshairs to\ncalibrate your touchscreen.\n \nUse the stylus for best\nresults!");
 
+    // set calibration defaults
+    SetCalibrationDefaults();
+
     // actual calibration
     for (u32 current_dot = 0; current_dot < countof(dot_positions); current_dot++) {
         // draw four crosshairs
@@ -48,7 +70,7 @@ bool ShowCalibrationDialog(void)
         }
     }
 
-    return HID_SetCalibrationData(calibrations, countof(dot_positions), 320, 240);
+    return HID_SetCalibrationData(calibrations, countof(dot_positions), SCREEN_WIDTH_BOT, SCREEN_HEIGHT);
 }
 
 void ShowTouchPlayground(void)
@@ -65,12 +87,49 @@ void ShowTouchPlayground(void)
         while (pressed & BUTTON_TOUCH) {
         	u16 tx, ty;
             HID_ReadTouchState(&tx, &ty);
-            if (tx < 320 && ty < 240)
+            if (tx < SCREEN_WIDTH_BOT && ty < SCREEN_HEIGHT)
                 DrawPixel(BOT_SCREEN, tx, ty, COLOR_BRIGHTYELLOW);
             DrawStringF(BOT_SCREEN, 16, 16, COLOR_STD_FONT, COLOR_STD_BG,
             	"Current touchscreen coordinates: %3.3d, %3.3d", tx, ty);
         	pressed = HID_ReadState();
         }
     }
-
+}
+
+bool CalibrateTouchFromFlash(void) {
+	HID_CalibrationData data[2];
+
+    // set calibration defaults
+    SetCalibrationDefaults();
+ 
+ 	// check SPIflash status
+    if (!spiflash_get_status())
+        return false;
+ 
+ 	// check NVRAM console ID
+    u32 console_id = 0;
+    spiflash_read(0x001C, 4, (u8*)&console_id);
+    if (((console_id >> 8) & 0xFF) != 0x57)
+        return false; // not a 3DS
+
+    // read and check DS fw user settings
+    // see: https://problemkaputt.de/gbatek.htm#dsfirmwareusersettings
+    u32 fw_usercfg_buf[0x100 / 0x4];
+    u8* fw_usercfg = (u8*) fw_usercfg_buf;
+    spiflash_read(0x1FE00, 0x100, fw_usercfg);
+    if (getle16(fw_usercfg + 0x72) != crc16_quick(fw_usercfg, 0x70)) {
+    	ShowPrompt(false, "ugh");
+    	return false; 
+    }
+
+    // get touchscreen calibration data from user settings
+    u8 *ts_data = fw_usercfg + 0x58;
+    for (int i = 0; i < 2; i++) {
+        int base = i * 6;
+        data[i].ts_raw = ts_data[base + 1] << 24 | ts_data[base + 0] << 16 | ts_data[base + 3] << 8 | ts_data[base + 2];
+        data[i].screen_x = (((int)ts_data[base + 4]) * SCREEN_WIDTH_BOT) / 256;
+        data[i].screen_y = (((int)ts_data[base + 5]) * SCREEN_HEIGHT) / 192;
+    }
+ 
+    return HID_SetCalibrationData(data, 2, SCREEN_WIDTH_BOT, SCREEN_HEIGHT);
 }

arm9/source/common/touchcal.h

@@ -2,5 +2,6 @@
 
 #include "common.h"
 
-bool ShowCalibrationDialog(void);
+bool ShowTouchCalibrationDialog(void);
 void ShowTouchPlayground(void);
+bool CalibrateTouchFromFlash(void);

arm9/source/godmode.c

@@ -2049,6 +2049,7 @@ u32 GodMode(int entrypoint) {
     AutoEmuNandBase(true);
     InitNandCrypto(entrypoint != ENTRY_B9S);
     InitExtFS();
+    CalibrateTouchFromFlash(); // !!! this may need some further checking
     
     // custom font handling
     if (CheckSupportFile("font.pbm")) {
@@ -2537,7 +2538,7 @@ u32 GodMode(int entrypoint) {
                         break;
                     }
                 } else if (user_select == calib) {
-                    ShowPrompt(false, "Touchscreen calibration %s!", (ShowCalibrationDialog()) ? "success" : "failed");
+                    ShowPrompt(false, "Touchscreen calibration %s!", (ShowTouchCalibrationDialog()) ? "success" : "failed");
                 } else if (user_select == playground) {
                     ShowTouchPlayground();
                 } else if (user_select == payloads) {
@@ -2599,6 +2600,7 @@ u32 ScriptRunner(int entrypoint) {
     AutoEmuNandBase(true);
     InitNandCrypto(entrypoint != ENTRY_B9S);
     InitExtFS();
+    CalibrateTouchFromFlash(); // !!! this may need some further checking
     
     while (CheckButton(BOOTPAUSE_KEY)); // don't continue while these keys are held
     while (timer_msec( timer ) < 500); // show splash for at least 0.5 sec

arm9/source/main.c

@@ -1,22 +1,12 @@
 #include "godmode.h"
 #include "power.h"
-#include "timer.h"
 #include "pxi.h"
-#include "i2c.h"
 
 #include "arm.h"
 #include "shmem.h"
 
 #include "hid.h"
 
-static const HID_CalibrationData default_calib = {
-    .screen_x = 0,
-    .screen_y = 0,
-    .ts_raw = 0
-    // ^ wrong: in my console it's 0x780086
-    // but this is very much console dependent
-    // so it's better to go with a sane default
-};
 
 void main(int argc, char** argv, int entrypoint)
 {
@@ -33,10 +23,6 @@ void main(int argc, char** argv, int entrypoint)
     // stored in the thread ID register in the ARM9
     ARM_InitSHMEM();
 
-    // Hardcoding this isn't ideal but it's better than
-    // leaving the system without any state to work with
-    HID_SetCalibrationData(&default_calib, 1, 320, 240);
-
     #ifdef SCRIPT_RUNNER
     // Run the script runner
     if (ScriptRunner(entrypoint) == GODMODE_EXIT_REBOOT)