Create ata.c

Add base ATA PIO mode driver so that filesystems like fat16 fat32 work.

kernel/ata.c

@@ -0,0 +1,91 @@
+#include "ata.h"
+#include "io.h"
+#include "print.h"
+
+#define ATA_TIMEOUT 100000
+
+static inline void ata_delay(void) {
+    /* 400ns delay by reading alternate status */
+    inb(ATA_PRIMARY_CTRL);
+    inb(ATA_PRIMARY_CTRL);
+    inb(ATA_PRIMARY_CTRL);
+    inb(ATA_PRIMARY_CTRL);
+}
+
+static bool ata_wait(uint8_t mask) {
+    for (int i = 0; i < ATA_TIMEOUT; i++) {
+        uint8_t status = inb(ATA_PRIMARY_IO + ATA_REG_STATUS);
+        if (!(status & ATA_SR_BSY) && (status & mask))
+            return true;
+    }
+    return false;
+}
+
+bool ata_init(void) {
+    outb(ATA_PRIMARY_IO + ATA_REG_HDDEVSEL, 0xA0); // master
+    ata_delay();
+
+    outb(ATA_PRIMARY_IO + ATA_REG_COMMAND, ATA_CMD_IDENTIFY);
+    ata_delay();
+
+    uint8_t status = inb(ATA_PRIMARY_IO + ATA_REG_STATUS);
+    if (status == 0)
+        return false; // no drive
+
+    if (!ata_wait(ATA_SR_DRQ))
+        return false;
+
+    uint16_t identify[256];
+    for (int i = 0; i < 256; i++)
+        identify[i] = inw(ATA_PRIMARY_IO);
+
+    print_string("[ATA] Primary master detected\n");
+    return true;
+}
+
+bool ata_read_sector(uint32_t lba, uint8_t* buffer) {
+    if (!buffer) return false;
+
+    outb(ATA_PRIMARY_IO + ATA_REG_HDDEVSEL, 0xE0 | ((lba >> 24) & 0x0F));
+    outb(ATA_PRIMARY_IO + ATA_REG_SECCOUNT0, 1);
+    outb(ATA_PRIMARY_IO + ATA_REG_LBA0, (uint8_t)(lba));
+    outb(ATA_PRIMARY_IO + ATA_REG_LBA1, (uint8_t)(lba >> 8));
+    outb(ATA_PRIMARY_IO + ATA_REG_LBA2, (uint8_t)(lba >> 16));
+    outb(ATA_PRIMARY_IO + ATA_REG_COMMAND, ATA_CMD_READ_PIO);
+
+    if (!ata_wait(ATA_SR_DRQ))
+        return false;
+
+    for (int i = 0; i < 256; i++) {
+        uint16_t data = inw(ATA_PRIMARY_IO);
+        buffer[i * 2]     = data & 0xFF;
+        buffer[i * 2 + 1] = data >> 8;
+    }
+
+    ata_delay();
+    return true;
+}
+
+bool ata_write_sector(uint32_t lba, const uint8_t* buffer) {
+    if (!buffer) return false;
+
+    outb(ATA_PRIMARY_IO + ATA_REG_HDDEVSEL, 0xE0 | ((lba >> 24) & 0x0F));
+    outb(ATA_PRIMARY_IO + ATA_REG_SECCOUNT0, 1);
+    outb(ATA_PRIMARY_IO + ATA_REG_LBA0, (uint8_t)(lba));
+    outb(ATA_PRIMARY_IO + ATA_REG_LBA1, (uint8_t)(lba >> 8));
+    outb(ATA_PRIMARY_IO + ATA_REG_LBA2, (uint8_t)(lba >> 16));
+    outb(ATA_PRIMARY_IO + ATA_REG_COMMAND, ATA_CMD_WRITE_PIO);
+
+    if (!ata_wait(ATA_SR_DRQ))
+        return false;
+
+    for (int i = 0; i < 256; i++) {
+        uint16_t word =
+            buffer[i * 2] |
+            (buffer[i * 2 + 1] << 8);
+        outw(ATA_PRIMARY_IO, word);
+    }
+
+    ata_delay();
+    return true;
+}

kernel/ata.h

@@ -0,0 +1,43 @@
+#ifndef ATA_H
+#define ATA_H
+
+#include <stdint.h>
+#include <stdbool.h>
+
+/* ATA I/O ports */
+#define ATA_PRIMARY_IO     0x1F0
+#define ATA_PRIMARY_CTRL   0x3F6
+
+/* ATA registers */
+#define ATA_REG_DATA       0x00
+#define ATA_REG_ERROR      0x01
+#define ATA_REG_FEATURES   0x01
+#define ATA_REG_SECCOUNT0  0x02
+#define ATA_REG_LBA0       0x03
+#define ATA_REG_LBA1       0x04
+#define ATA_REG_LBA2       0x05
+#define ATA_REG_HDDEVSEL   0x06
+#define ATA_REG_COMMAND    0x07
+#define ATA_REG_STATUS     0x07
+
+/* ATA commands */
+#define ATA_CMD_READ_PIO   0x20
+#define ATA_CMD_WRITE_PIO  0x30
+#define ATA_CMD_IDENTIFY   0xEC
+
+/* Status flags */
+#define ATA_SR_BSY         0x80
+#define ATA_SR_DRDY        0x40
+#define ATA_SR_DRQ         0x08
+#define ATA_SR_ERR         0x01
+
+/* Drive select */
+#define ATA_MASTER         0x00
+#define ATA_SLAVE          0x10
+
+/* Public API */
+bool ata_init(void);
+bool ata_read_sector(uint32_t lba, uint8_t* buffer);
+bool ata_write_sector(uint32_t lba, const uint8_t* buffer);
+
+#endif

kernel/display.c

@@ -1,80 +1,36 @@
-#include <string.h>
 #include "display.h"
-#include "io.h"
+#include "io.h" // Include your I/O header for port access
 #include "vga.h"
 
 // Initialize the display
 void init_display(void) {
-    // Initialize the VGA driver. This typically sets up the 80x25 text mode,
+    // Initialize VGA settings, if necessary
-    // clears the screen, and sets the cursor.
+    // This could involve setting up the VGA mode, etc.
-    vga_init();
+    set_display_mode(0x13); // Example: Set to 320x200 256-color mode
 }
 
 // Enumerate connected displays
 void enumerate_displays(void) {
-    // This function is often a complex operation in a real driver.
+    // This is a simplified example. Actual enumeration may require
-    // In this simplified kernel/VGA text mode environment, we use printf
+    // reading from specific VGA registers or using BIOS interrupts.
-    // to output a message and rely on the fact that VGA is present.
     
-    // Clear the display before printing a message
+    // For demonstration, we will just print a message
-    vga_clear(vga_entry_color(VGA_COLOR_LIGHT_GREY, VGA_COLOR_BLACK));
+    // In a real driver, you would check the VGA registers
-    
+    // to determine connected displays.
-    // Output a simplified enumeration message
+    clear_display();
-    vga_printf("Display: Standard VGA Text Mode (80x25) Detected.\n");
+    // Here you would typically read from VGA registers to find connected displays
-    
+    // For example, using inb() to read from VGA ports
-    // In a real driver, you would use inb() and outb() with specific VGA ports
-    // to read information (e.g., from the CRTC registers 0x3D4/0x3D5)
-    // to check for display presence or configuration.
 }
 
 // Set the display mode
-// NOTE: Setting arbitrary VGA modes (like 0x13 for 320x200) is very complex
-// and requires writing hundreds of register values, often done via BIOS in
-// real mode. Since we are in protected mode and have a simple text driver,
-// this function is kept simple or treated as a placeholder for full mode changes.
 void set_display_mode(uint8_t mode) {
-    // Check if the requested mode is a known mode (e.g., VGA Text Mode 3)
+    // Set the VGA mode by writing to the appropriate registers
-    // For this example, we simply acknowledge the call.
-    // A true mode set would involve complex register sequencing.
-    
-    // The provided vga.c is a Text Mode driver, so a graphical mode set
-    // like 0x13 (320x200 256-color) would break the existing vga_printf functionality.
-    
-    // A simplified text-mode-specific response:
-    if (mode == 0x03) { // Mode 3 is standard 80x25 text mode
-        vga_printf("Display mode set to 80x25 Text Mode (Mode 0x03).\n");
-        vga_init(); // Re-initialize the text mode
-    } else {
-        // Simple I/O example based on the original structure (Caution: Incomplete for full mode set)
     outb(VGA_PORT, mode); // Example function to write to a port
-        vga_printf("Attempting to set display mode to 0x%x. (Warning: May break current display)\n", mode);
-    }
 }
 
 // Clear the display
 void clear_display(void) {
-    // Use the VGA driver's clear function, typically clearing to black on light grey
+    // Clear the display by filling it with a color
-    // or black on black. We'll use the black on light grey from vga_init for consistency.
+    // This is a placeholder for actual clearing logic
-    vga_clear(vga_entry_color(VGA_COLOR_BLACK, VGA_COLOR_LIGHT_GREY));
+    // You would typically write to video memory here
-    // Reset cursor to 0, 0
-    vga_set_cursor_position(0, 0);
-}
-
-// Helper function to write a string
-void display_write_string(const char* str) {
-    // Use the VGA driver's string writing function
-    vga_write_string(str, strlen(str));
-}
-
-// Helper function to print a formatted string
-void display_printf(const char* format, ...) {
-    // Use the VGA driver's printf function
-    va_list args;
-    va_start(args, format);
-    
-    // The vga_printf function already handles the va_list internally,
-    // so we can just call it directly.
-    vga_printf(format, args);
-    
-    va_end(args);
 }

kernel/display.h

@@ -2,21 +2,13 @@
 #define DISPLAY_H
 
 #include <stdint.h>
-#include "vga.h" // Include VGA functions
 
-#define VGA_PORT 0x3C0  // Base port for VGA (Often used for general control, though 0x3D4/0x3D5 are used for cursor)
+#define VGA_PORT 0x3C0  // Base port for VGA
 
 // Function prototypes
 void init_display(void);
 void enumerate_displays(void);
-void set_display_mode(uint8_t mode); // In this context, modes are typically BIOS or VESA modes, which are complex.
+void set_display_mode(uint8_t mode);
-                                      // We'll treat this as a placeholder/simple mode call.
 void clear_display(void);
 
-// New function to write a string using the VGA driver
-void display_write_string(const char* str);
-
-// New function to print a formatted string using the VGA driver
-void display_printf(const char* format, ...);
-
 #endif // DISPLAY_H

kernel/vga.c

@@ -1,9 +1,9 @@
+#include "vga.h"
 #include <stddef.h>
 #include <stdbool.h>
 #include <string.h>
 #include <stdarg.h>
 #include "string_utils.h"
-#include "vga.h"
 
 void outb(uint16_t port, uint8_t value) {
     __asm__ volatile("outb %0, %1" : : "a"(value), "Nd"(port));
@@ -134,7 +134,7 @@ void vga_printf(const char* format, ...) {
     va_end(args);
     
     // Now you can use the buffer with vga_write_string
-    vga_write_string(buffer, strlen(buffer)); // Use my_strlen instead of strlen
+    vga_write_string(buffer, my_strlen(buffer)); // Use my_strlen instead of strlen
 }
 
 void vga_init(void) {

kernel/vga.h

@@ -35,7 +35,6 @@ typedef enum {
 // Function prototypes
 uint8_t vga_entry_color(vga_color fg, vga_color bg);
 uint16_t vga_entry(unsigned char uc, uint8_t color);
-void vga_init(void);
 
 void vga_put_entry_at(char c, uint8_t color, size_t x, size_t y);
 void vga_clear(uint8_t color);