Improved ahci, not sure if it is working tho!

Author: pradosh-arduino

disk.txt

@@ -35,13 +35,15 @@ void detect_ahci_devices(ahci_controller* ahci_ctrl) {
                 printf("SATA Disk detected at port %d", i);
                 uint8_t sector_buffer[SECTOR_SIZE * 1]; // Buffer to store 5 sectors
 
-                if (read_sectors(0, 1, sector_buffer) != 0) {
+                if (read_sectors(1, 1, sector_buffer) != 0) {
                     error("sector reading failed!", __FILE__);
                 }
 
                 // for(int x = 0; x < SECTOR_SIZE * 1; x++){
-                //     debug_printf("%u ", sector_buffer[x]);
+                //     debug_printf("%u ", (int)sector_buffer[x]);
                 // }
+                // debug_print("\n");
+
             } else if (sig == satapi_disk) {
                 printf("SATAPI Disk detected at port %d", i);
             } else if (sig == semb_disk) {
@@ -75,35 +77,81 @@ prdt_entry_t* allocate_prdt(size_t num_entries) {
     return (prdt_entry_t*)malloc(num_entries * sizeof(prdt_entry_t)); 
 }
 
+prdt_entry_t* free_prdt(prdt_entry_t* a) {
+    return (prdt_entry_t*)free(a); 
+}
+
 int read_sectors(uint32_t lba, uint32_t sector_count, void* buffer) {
-    // 1. Get AHCI command header and PRDT
+    if (sector_count == 0) return -1; // Handle invalid input
+
     ahci_command_header_t* cmd_header = get_free_command_header();
+    if (!cmd_header) return -1; // Handle allocation failure
+
     prdt_entry_t* prdt = allocate_prdt(1);
+    if (!prdt) {
+        // free_command_header(cmd_header);
+        return -1;
+    }
 
-    // 2. Fill command FIS
-    cmd_header->cfis[0] = 0x27; // ATA command: Read
-    cmd_header->cfis[2] = lba & 0xFF;
-    cmd_header->cfis[3] = (lba >> 8) & 0xFF;
-    cmd_header->cfis[4] = (lba >> 16) & 0xFF;
-    cmd_header->cfis[5] = (lba >> 24) & 0xFF;
-    cmd_header->cfis[7] = sector_count & 0xFF;
-    cmd_header->cfis[8] = (sector_count >> 8) & 0xFF;
-
-    // 3. Fill PRDT
-    prdt[0].dba = (uint32_t)buffer; // Address of the buffer to store data
-    prdt[0].dbc = sector_count * SECTOR_SIZE - 1; // Number of bytes to transfer
-
-    // 4. Set up command header
-    cmd_header->prdtl = sizeof(prdt_entry_t); // Size of PRDT
+    // 1. Fill command FIS (Corrected for 48-bit LBA if needed)
+    cmd_header->cfis[0] = 0x20; // ATA command: Read (0x20 for 28-bit, 0x24 for 48-bit)
+
+    if (lba > 0xFFFFFFF || (lba + sector_count) > 0xFFFFFFF) { // Check for 28-bit overflow
+      cmd_header->cfis[0] = 0x24; // Use 48-bit command if needed
+      cmd_header->cfis[1] = 0;
+      cmd_header->cfis[2] = lba & 0xFF;
+      cmd_header->cfis[3] = (lba >> 8) & 0xFF;
+      cmd_header->cfis[4] = (lba >> 16) & 0xFF;
+      cmd_header->cfis[5] = (lba >> 24) & 0xFF;
+      cmd_header->cfis[6] = (lba >> 32) & 0xFF; // LBA 48 bit
+      cmd_header->cfis[7] = (lba >> 40) & 0xFF;  // LBA 48 bit
+      cmd_header->cfis[8] = sector_count & 0xFF;
+      cmd_header->cfis[9] = (sector_count >> 8) & 0xFF; // Sector count 16 bit
+    } else {
+      cmd_header->cfis[2] = lba & 0xFF;
+      cmd_header->cfis[3] = (lba >> 8) & 0xFF;
+      cmd_header->cfis[4] = (lba >> 16) & 0xFF;
+      cmd_header->cfis[5] = (lba >> 24) & 0xFF;
+      cmd_header->cfis[7] = sector_count & 0xFF;
+      cmd_header->cfis[8] = (sector_count >> 8) & 0xFF;
+    }
+
+
+    // 2. Fill PRDT (Corrected DBC)
+    prdt[0].dba = (uint32_t)buffer;
+    prdt[0].dbc = sector_count * SECTOR_SIZE - 1; // Byte count, not sector count
+
+    // 3. Set up command header
+    cmd_header->prdtl = 1; // Number of PRDT entries, not size in bytes.
     cmd_header->prdt = (uint32_t)prdt;
 
-    // 5. Issue the command
-    cmd_header->ci = 1; // Issue command
+    // 4. Issue the command
+    cmd_header->ci = 1;
 
+    // 5. **CRITICAL:** Wait for command completion.  This is the most likely source of your original problem.
+    wait_for_command_completion(cmd_header);
 
-    sleep(2);
+    // 6. Check for errors (add this!)
+    if (cmd_header->ciss & 0x1) { // Error bit set
+    //   free_command_header(cmd_header);
+      free_prdt(prdt);
+        return -1; // Or a more specific error code.
+    }
+
+    // free_command_header(cmd_header);
+    free_prdt(prdt);
 
-    // 7. Read data from the buffer
+    return 0;
+}
 
-    return 0; // Command successful
-}
+void wait_for_command_completion(ahci_command_header_t* cmd_header) {
+    volatile uint32_t* status_reg = (volatile uint32_t*)(cmd_header + 0x08); // Example, adjust as needed.
+      while (1) {
+          if (! (status_reg[0] & (1 << 7))) { // Check BSY (Busy) bit in PxSATASTATUS register
+            break;
+          }
+      }
+  
+      // Check the command complete (CC) bit in the command header.
+    //   while (cmd_header->ci) ; // Wait for CI to clear (command complete)
+  }