backup 8.29.21

1 files changed, 136 insertions, 44 deletions

diff --git a/src/kernel/klog.c b/src/kernel/klog.c
index 52444b1..c62c4d3 100644
--- a/src/kernel/klog.c
+++ b/src/kernel/klog.c
@@ -1,57 +1,104 @@
 #include <stdint.h>
-#include <serial.h>
 #include <io.h>
 #include <printf.h>
-#include <kernel.h>
+#include <addr.h>
 #include <stdbool.h>
 #include <libc.h>
+#include <klog.h>
 
-//README 
-//this file has some temporary workarounds until I get further into development
-//this isn't going to be the serial driver I end up keeping
+//right now, this program is simply for debuging.
+//Later in development, we will hook it up to a TTY, impliment FCS, etc
 
 #define VIDEO_BUFFER PHYS_TO_VIRT(0xb8000)
 #define MAX_LOOPBACK_ATTEMPTS 20
 
-//later we'll set it up for interrupting instead of polling
-bool init_serial(uint16_t port) {
-  outb_wait(port + 1, 0x00); 
-  outb_wait(port + 2, 0x00); 
-  outb_wait(port + 3, 0x80); 
-  outb_wait(port + 0, 0x01); //here
-  outb_wait(port + 1, 0x00);
-  outb_wait(port + 3, 0x03); 
-  outb_wait(port + 2, 0xc7); 
-  outb_wait(port + 4, 0x0b); 
-  outb_wait(port + 4, 0x1e); 
-
-
-  //we shouldn't accept this as a loopback success.
-  //I'm making an exception because my dell desktop has a faulty serial port
-  //that requires some extra effort.
-
-  uint8_t loopback_byte;
-  for(int attempts = 0; attempts < MAX_LOOPBACK_ATTEMPTS; attempts++) {
-    outb_wait(port + 0, 0xae); // test char
-    loopback_byte = inb(port);
-    if(loopback_byte == 0xae) break;
-  }
+#define KLOG_COM1     0
+#define KLOG_COM2     1
+#define KLOG_COM3     2
+#define KLOG_COM4     3
+#define KLOG_SCREEN   4
+
+static int debug_output = KLOG_SCREEN;
+
+#define SERIAL_THR                0   //transmitter holding buffer
+#define SERIAL_RBR                1   //receiving holding buffer
+#define SERIAL_DLL                0   //divisor latch low byte
+#define SERIAL_DLH                1   //divisor latch high byte
+#define SERIAL_FCR                2
+#define SERIAL_IIR                2
+#define SERIAL_LCR                3
+#define SERIAL_MCR                4
+#define SERIAL_LSR                5
+#define SERIAL_MSR                6
+#define SERIAL_SR                 7
+
+#define COM1 0x3f8
+#define COM2 0x2f8
+#define COM3 0x3e8
+#define COM4 0x2e8
+
+uint16_t serial_ports[4] = {COM1, COM2, COM3, COM4};
+
+/**
+enum com_ports {
+  COM1 = 0x3f8,
+  COM2 = 0x2f8,
+  COM3 = 0x3e8,
+  COM4 = 0x2e8
+};
+**/
+
+
+static bool detect_serial(uint16_t port) {
+  outb(port + SERIAL_FCR, 0xe7);
+  outb(port + SERIAL_SR, 0xba);
+  if((inb(port + SERIAL_IIR) & (1 << 6)) && (inb(port + SERIAL_SR) == 0xba)) {
+    outb_wait(port + 1, 0x00); 
+    outb_wait(port + 2, 0x00); 
+    outb_wait(port + 3, 0x80); 
+    outb_wait(port + 0, 0x01);
+    outb_wait(port + 1, 0x00);
+    outb_wait(port + 3, 0x03); 
+    outb_wait(port + 2, 0xc7); 
+    outb_wait(port + 4, 0x0b); 
+    outb_wait(port + 4, 0x1e); 
 
-  if(loopback_byte != 0xae) {
-    //I'm sorry if these next few lines give you a stroke. They gave me one.
+
+    uint8_t loopback_byte;
+    for(int attempts = 0; attempts < MAX_LOOPBACK_ATTEMPTS; attempts++) {
+      outb_wait(port + 0, 0xae);
+      loopback_byte = inb(port);
+      if(loopback_byte == 0xae) break;
+    }
+
+    if(loopback_byte != 0xae) {
+      //you better delete this once you get tty drivers working...
+      int a = 0 / 0;
+    }
     
-    //My old Dell test desktop has disfunctional serial hardware that only works after a reboot.
-    //Seeing we don't have ACPI set up yet, we can't reboot without crashing.
-    //IM GOING TO REMOVE THIS ONCE I DEVELOP THE "REAL" SERIAL DRIVER!!!! 
-    asm("mov rax, 0\n"
-        "div rax\n");
-    return false;
+    outb_wait(port + 4, 0x0f); 
+    return true;
   }
-  
-  outb_wait(port + 4, 0x0f); 
-  return true;
+  return false;
 }
 
+
+//this function is going to be teleted after ttys work.
+//but, for now, if a serial port is detected, it'll set debug_output to 0-3 (com port #).
+//debug_output == 4 is for screen output.
+void init_klog() {
+  for(unsigned int p = 0; p < (sizeof(serial_ports) / sizeof(uint16_t)); p++) {
+    if(detect_serial(serial_ports[p])) {
+      debug_output = p;
+      return;
+    }
+  }
+  debug_output = KLOG_SCREEN;
+  _putchar('\n');
+}
+
+
+
 void _putchar_serial(uint16_t port, char msg) {
   while(!(inb(port + 5) & 0x20)); //wait for transmit to be done
   outb_wait(port, msg);
@@ -80,13 +127,10 @@ void next_line() {
 }
 
 void move_cursor(unsigned int x, unsigned int y) {
-  //yeah yeah yeah, it doens't test for overflows... I'm gonna delete this once i get serial working
-  //on my second desktop
   on_char = x;
   on_line = y;
 }
 
-//until we get serial working on hp
 void _putchar_screen(char msg) {
   if(on_char >= 80) {
     next_line();
@@ -94,7 +138,55 @@ void _putchar_screen(char msg) {
     next_line();
     return;
   }
-  char *screen_buffer = (void *)((uint64_t)VIDEO_BUFFER + ((on_line * 160) + (on_char * 2)));
-  *screen_buffer = msg;
+  *(char *)((uint64_t)VIDEO_BUFFER + ((on_line * 160) + (on_char * 2))) = msg;
   on_char++;
 }
+
+
+
+void _putchar(char character) {
+  if(debug_output < (sizeof(serial_ports) / sizeof(uint16_t))) {
+    _putchar_serial(serial_ports[debug_output], character); 
+  }
+  else {
+    _putchar_screen(character);
+  }
+}
+
+
+
+
+/**
+ * Set the value "0xE7" to the FCR to test the status of the FIFO flags.
+Read the value of the IIR to test for what flags actually got set.
+If Bit 6 is set Then
+  If Bit 7 is set Then
+    If Bit 5 is set Then
+      UART is 16750 (64 bit fifo)
+    Else
+      UART is 16550A (idk why this matters, 16 bit fifo)
+    End If
+  Else
+    UART is 16550 (16 bit fifo)
+  End If
+Else you know the chip doesn't use FIFO, so we need to check the scratch register
+  Set some arbitrary value like 0x2A to the Scratch Register.
+  If the arbitrary value comes back identical
+    UART is 16450 (idk why this matters, 1 byte at a time)
+  Else
+    UART is 8250 (one byte at a time)
+  End If
+End If
+
+#define UART_16750    0
+#define UART_16550A   1
+#define UART_16550    2
+#define UART_16450    3
+#define UART_8250     4
+
+#define KLOG_COM1     0
+#define KLOG_COM2     1
+#define KLOG_COM3     2
+#define KLOG_COM4     3
+#define KLOG_SCREEN   4 * 5 // 5 leaves enough space for com ports
+**/