From d2f53626aece4e35ec09f29dbd7cd771ab218587 Mon Sep 17 00:00:00 2001
From: TuxSH <tuxsh@sfr.fr>
Date: Tue, 10 May 2016 01:27:58 +0200
Subject: [PATCH] Add precise and reliable time measurement (with a resolution
 of 67MHz).

Splash screens now last 3 seconds after they have been loaded.
The delay after pressing START in the configuration menu is now 2s long.
---
 source/config.c |  5 +++--
 source/draw.c   |  5 +++--
 source/draw.h   |  2 +-
 source/firm.c   | 12 ++++++++++--
 source/utils.c  | 31 ++++++++++++++++++++++++++-----
 source/utils.h  |  9 +++++++--
 6 files changed, 50 insertions(+), 14 deletions(-)

diff --git a/source/config.c b/source/config.c
index 969bb33..0e2e427 100644
--- a/source/config.c
+++ b/source/config.c
@@ -185,6 +185,7 @@ void configureCFW(const char *configPath)
         deinitScreens();
         PDN_GPU_CNT = 1;
     }
-
-    delay(0x1400000);
+    
+    u64 t0 = chrono();
+    while(chrono() - t0 < 2 * TICKS_PER_SEC); //wait for 1.5s
 }
\ No newline at end of file
diff --git a/source/draw.c b/source/draw.c
index c8f1fab..1f13e9d 100644
--- a/source/draw.c
+++ b/source/draw.c
@@ -33,14 +33,15 @@ void clearScreens(void)
     memset32(fb->bottom, 0, 0x38400);
 }
 
-void loadSplash(void)
+u32 loadSplash(void)
 {
     initScreens();
 
     //Don't delay boot if no splash image is on the SD
     if(fileRead(fb->top_left, "/luma/splash.bin") +
        fileRead(fb->bottom, "/luma/splashbottom.bin"))
-        delay(0x1400000);
+        return 1;
+    return 0;
 }
 
 void drawCharacter(char character, int posX, int posY, u32 color)
diff --git a/source/draw.h b/source/draw.h
index a8959bf..18b46d0 100644
--- a/source/draw.h
+++ b/source/draw.h
@@ -19,7 +19,7 @@
 #define COLOR_RED   0x0000FF
 #define COLOR_BLACK 0x000000
 
-void loadSplash(void);
+u32 loadSplash(void);
 void clearScreens(void);
 void drawCharacter(char character, int posX, int posY, u32 color);
 int drawString(const char *string, int posX, int posY, u32 color);
\ No newline at end of file
diff --git a/source/firm.c b/source/firm.c
index 4a01557..82dcb04 100755
--- a/source/firm.c
+++ b/source/firm.c
@@ -23,6 +23,8 @@ u32 config,
     firmSource,
     emuOffset;
 
+u64 chronoWhenSplashLoaded = 0;
+
 void main(void)
 {
     u32 bootType,
@@ -33,6 +35,8 @@ void main(void)
         needConfig,
         newConfig,
         emuHeader;
+    
+    startChrono(0); //Start the chronometer. It shouldn't be reset.
 
     //Detect the console being used
     console = PDN_MPCORE_CFG == 7;
@@ -145,8 +149,9 @@ void main(void)
                 loadPayload(pressed);
 
             //If screens are inited or the corresponding option is set, load splash screen
-            if(PDN_GPU_CNT != 1 || CONFIG(7)) loadSplash();
-
+            if(PDN_GPU_CNT != 1 || CONFIG(7)) chronoWhenSplashLoaded = (u64) loadSplash();
+            if(chronoWhenSplashLoaded) chronoWhenSplashLoaded = chrono(); 
+            
             //If R is pressed, boot the non-updated NAND with the FIRM of the opposite one
             if(pressed & BUTTON_R1)
             {
@@ -446,6 +451,9 @@ static inline void launchFirm(u32 firstSectionToCopy, u32 bootType)
     for(u32 i = firstSectionToCopy; i < 4 && section[i].size; i++)
         memcpy(section[i].address, (u8 *)firm + section[i].offset, section[i].size);
 
+    while(chronoWhenSplashLoaded && chrono() - chronoWhenSplashLoaded < 3 * TICKS_PER_SEC);
+    stopChrono();
+    
     //Determine the ARM11 entry to use
     vu32 *arm11;
     if(bootType) arm11 = (u32 *)0x1FFFFFFC;
diff --git a/source/utils.c b/source/utils.c
index ba0f805..5c10112 100644
--- a/source/utils.c
+++ b/source/utils.c
@@ -33,13 +33,34 @@ u32 waitInput(void)
     return key;
 }
 
-void delay(u64 length)
-{
-    while(length--) __asm("mov r0, r0");
-}
-
 void mcuReboot(void)
 {
     i2cWriteRegister(I2C_DEV_MCU, 0x20, 1 << 2);
     while(1);
+}
+
+//TODO: add support for TIMER IRQ
+void startChrono(u64 initialTicks)
+{
+    //Based on a NATIVE_FIRM disassembly
+    
+    *(vu16 *)(0x10003002 + 4 * 0) = 0; //67MHz
+    for(u32 i = 1; i < 4; i++) *(vu16 *)(0x10003002 + 4 * i) = 4; //Count-up
+    
+    for(u32 i = 0; i < 4; i++) *(vu16 *)(0x10003000 + 4 * i) = (u16)(initialTicks >> (16 * i)); 
+    
+    *(vu16 *)(0x10003002 + 4 * 0) = 0x80; //67MHz; enabled
+    for(u32 i = 1; i < 4; i++) *(vu16 *)(0x10003002 + 4 * i) = 0x84; //Count-up; enabled
+}
+
+u64 chrono(void)
+{
+    u64 res = 0;
+    for(u32 i = 0; i < 4; i++) res |= *(vu16 *)(0x10003000 + 4 * i) << (16 * i);
+    return res;
+}
+
+void stopChrono(void)
+{
+    for(u32 i = 1; i < 4; i++) *(vu16 *)(0x10003002 + 4 * i) &= ~0x80;
 }
\ No newline at end of file
diff --git a/source/utils.h b/source/utils.h
index c95778e..e2ef8ff 100644
--- a/source/utils.h
+++ b/source/utils.h
@@ -7,5 +7,10 @@
 #include "types.h"
 
 u32 waitInput(void);
-void delay(u64 length);
-void mcuReboot(void);
\ No newline at end of file
+void mcuReboot(void);
+
+#define TICKS_PER_SEC   67027964ULL
+
+void startChrono(u64 initialTicks);
+u64 chrono(void);
+void stopChrono(void);
\ No newline at end of file