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/vesa.c

@@ -1,98 +0,0 @@
-#include "vesa.h"
-#include "io.h"
-#include "print.h"
-
-// VESA mode and controller information
-#define VESA_BIOS_INT 0x10
-#define VESA_BIOS_FUNC 0x4F
-
-// Function to call BIOS with specific VESA function
-static bool vesa_bios_call(uint16_t function, uint16_t* eax, uint32_t* ebx, uint32_t* ecx, uint32_t* edx) {
-    // Set up registers for VESA function call
-    __asm__ __volatile__(
-        "movw %1, %%ax\n"           // Move function number into AX
-        "int $0x10\n"                // Call BIOS interrupt 0x10 (VESA)
-        "movw %%ax, %0\n"            // Move return value in AX to the return variable
-        : "=m"(*eax)                 // Output operand (eax)
-        : "m"(function)              // Input operand (function number)
-        : "%eax", "%ebx", "%ecx", "%edx", "memory"
-    );
-    // Check for success (return values vary depending on the function)
-    return *eax == 0x004F;
-}
-
-// Set the VESA video mode
-bool vesa_set_mode(uint16_t mode) {
-    uint16_t eax = VBE_FUNCTION_SET_MODE;
-    uint32_t ebx = mode;
-    uint32_t ecx = 0;
-    uint32_t edx = 0;
-    
-    if (vesa_bios_call(VBE_FUNCTION_SET_MODE, &eax, &ebx, &ecx, &edx)) {
-        return true;
-    }
-    return false;
-}
-
-// Get the VESA mode information
-bool vesa_get_mode_info(uint16_t mode, vbe_mode_info_t* info) {
-    uint16_t eax = VBE_FUNCTION_GET_MODE_INFO;
-    uint32_t ebx = mode;
-    uint32_t ecx = 0;
-    uint32_t edx = 0;
-
-    if (vesa_bios_call(VBE_FUNCTION_GET_MODE_INFO, &eax, &ebx, &ecx, &edx)) {
-        // Copy the information into the provided struct
-        uint32_t base = (uint32_t)info;
-        __asm__ __volatile__(
-            "movw %%bx, %%es:%%di\n"
-            : 
-            : "b" (base)
-            : "%es", "%di", "memory"
-        );
-        return true;
-    }
-    return false;
-}
-
-// Get the VESA controller information
-bool vesa_get_controller_info(vbe_controller_info_t* info) {
-    uint16_t eax = VBE_FUNCTION_GET_CONTROLLER_INFO;
-    uint32_t ebx = 0;
-    uint32_t ecx = 0;
-    uint32_t edx = 0;
-
-    if (vesa_bios_call(VBE_FUNCTION_GET_CONTROLLER_INFO, &eax, &ebx, &ecx, &edx)) {
-        // Copy controller information into the provided struct
-        uint32_t base = (uint32_t)info;
-        __asm__ __volatile__(
-            "movw %%bx, %%es:%%di\n"
-            : 
-            : "b" (base)
-            : "%es", "%di", "memory"
-        );
-        return true;
-    }
-    return false;
-}
-
-// Return pointer to the VESA framebuffer
-void* vesa_get_framebuffer(void) {
-    vbe_mode_info_t mode_info;
-    if (vesa_get_mode_info(0x101, &mode_info)) {
-        return (void*)mode_info.PhysBasePtr;
-    }
-    return NULL;
-}
-
-// Clear the screen with a color
-void vesa_clear_screen(uint32_t color) {
-    uint32_t* framebuffer = (uint32_t*)vesa_get_framebuffer();
-    if (framebuffer) {
-        for (int y = 0; y < 480; y++) { // For 640x480 mode
-            for (int x = 0; x < 640; x++) {
-                framebuffer[y * 640 + x] = color;
-            }
-        }
-    }
-}

kernel/vesa.h

@@ -1,67 +0,0 @@
-#ifndef VESA_H
-#define VESA_H
-
-#include <stdint.h>
-#include <stdbool.h>
-
-// VESA BIOS Extension 2.0 Function Calls
-#define VBE_FUNCTION_SET_MODE        0x4F02
-#define VBE_FUNCTION_GET_MODE_INFO   0x4F01
-#define VBE_FUNCTION_GET_CONTROLLER_INFO 0x4F00
-#define VBE_FUNCTION_SET_DISPLAY_START 0x4F05
-
-// VESA Mode Information Structure (VBE 2.0)
-typedef struct {
-    uint16_t ModeAttributes;      // Mode attributes
-    uint8_t WinAAttributes;       // Window A attributes
-    uint8_t WinBAttributes;       // Window B attributes
-    uint16_t WinGranularity;      // Window granularity
-    uint16_t WinSize;             // Window size
-    uint16_t WinASegment;         // Window A segment address
-    uint16_t WinBSegment;         // Window B segment address
-    uint32_t WinFuncPtr;          // Function pointer for window
-    uint16_t BytesPerScanLine;    // Bytes per scanline
-    uint16_t XResolution;         // Horizontal resolution in pixels
-    uint16_t YResolution;         // Vertical resolution in pixels
-    uint8_t XCharSize;            // Character cell width
-    uint8_t YCharSize;            // Character cell height
-    uint8_t NumberOfPlanes;       // Number of memory planes
-    uint8_t BitsPerPixel;         // Bits per pixel
-    uint8_t NumberOfBanks;        // Number of banks
-    uint8_t MemoryModel;          // Memory model type
-    uint8_t BankSize;             // Bank size in kB
-    uint8_t NumberOfImagePages;   // Number of image pages
-    uint8_t Reserved0;            // Reserved
-    uint8_t RedMaskSize;          // Red mask size
-    uint8_t RedFieldPosition;     // Red field position
-    uint8_t GreenMaskSize;        // Green mask size
-    uint8_t GreenFieldPosition;   // Green field position
-    uint8_t BlueMaskSize;         // Blue mask size
-    uint8_t BlueFieldPosition;    // Blue field position
-    uint8_t RsvdMaskSize;         // Reserved mask size
-    uint8_t RsvdFieldPosition;    // Reserved field position
-    uint8_t DirectColorModeInfo;  // Direct color mode info
-    uint32_t PhysBasePtr;         // Physical base address of the linear framebuffer
-    uint32_t OffScreenMemOff;     // Offset to off-screen memory
-    uint16_t OffScreenMemSize;    // Size of off-screen memory
-    uint8_t Reserved1[206];       // Reserved
-} __attribute__((packed)) vbe_mode_info_t;
-
-// VESA Controller Information
-typedef struct {
-    uint8_t VESAVersion[2];       // VESA version
-    uint32_t OEMStringPtr;        // Pointer to OEM string
-    uint8_t Capabilities[4];      // Capabilities of the controller
-    uint32_t VideoModePtr;        // Pointer to supported video modes
-    uint16_t TotalMemory;         // Total video memory (in 64KB)
-    uint8_t Reserved[4];          // Reserved
-} __attribute__((packed)) vbe_controller_info_t;
-
-// Function Prototypes
-bool vesa_set_mode(uint16_t mode);
-bool vesa_get_mode_info(uint16_t mode, vbe_mode_info_t* info);
-bool vesa_get_controller_info(vbe_controller_info_t* info);
-void* vesa_get_framebuffer(void);
-void vesa_clear_screen(uint32_t color);
-
-#endif // VESA_H