// ahci.c - AHCI driver, interrupt-driven with per-drive async IRP queue. // Supports SATA drives only (no ATAPI). Registers each found drive with the // kernel disk device registry via IoRegisterDiskDevice(). // // Memory model: // MmAllocateContiguous(n) returns a physical address for n*4K pages. // hal->PhysToVirt(phys) converts to kernel virtual address. // DMA buffers are bounce-buffered (allocated via MmAllocateContiguous) to // avoid needing a VirtToPhys conversion for arbitrary kernel pointers. // // Async I/O model (IRP path): // Each drive has a dedicated kernel worker thread (AhciWorker) that blocks // on a per-drive counting semaphore. Callers submit IRPs through IoCallDriver, // which dispatches to AHCI and enqueues the IRP. The worker dequeues // one IRP at a time, runs the synchronous hardware transfer (blocking the // worker, NOT the submitting thread), then writes irp->Status and fires // irp->CompletionEvent / irp->CompletionFn. // // This gives true async I/O from the caller's perspective: IoSubmitIrp() // returns STATUS_PENDING immediately. Multiple callers can have outstanding // requests against different drives concurrently without stalling each other. // // NCQ extension (future work - see "NCQ TODO" comments): // To saturate modern SSDs, replace the serialised single-slot model with // Native Command Queuing: // • Allocate per-slot bounce buffers (NUM_NCQ_SLOTS × SLOT_BOUNCE_BYTES). // • Use ATA_CMD_READ_FPDMA_QUEUED / WRITE_FPDMA_QUEUED. // • Encode the slot tag in FIS.countl bits 7:3. // • Issue via port->sact (NCQ active) rather than port->ci. // • In AhciIsr: completed slots = prev_sact ^ port->sact; look up // slot_irp[slot] and fire each completion from within the ISR. // • The worker becomes a pure dispatcher: grab a free slot, build the // command, issue it, return immediately. No per-slot KeWaitForEvent. // // Interrupt model (unchanged): // GHC.IE and per-port PORT_IE are enabled after each port is initialised. // AhciIsr fires on the PCI IRQ line, captures/clears port status, and queues // a per-drive DPC. The DPC signals completionEvent outside hard IRQ context. // port_issue_cmd blocks the worker thread on KeWaitForEvent instead of // spinning on CI. port_issue_cmd_poll is kept for early init (IDENTIFY) // before the scheduler is live. #include #include #include #include #include #include #include #include #include #include #include #include #include // --------------------------------------------------------------------------- typedef enum { FIS_TYPE_REG_H2D = 0x27, FIS_TYPE_REG_D2H = 0x34, FIS_TYPE_DMA_ACT = 0x39, FIS_TYPE_DMA_SETUP = 0x41, FIS_TYPE_DATA = 0x46, FIS_TYPE_BIST = 0x58, FIS_TYPE_PIO_SETUP = 0x5F, FIS_TYPE_DEV_BITS = 0xA1, } FIS_TYPE; #pragma pack(push, 1) // Register FIS - Host to Device (H2D) typedef struct { uint8_t fis_type; // FIS_TYPE_REG_H2D uint8_t pmport : 4; uint8_t rsv0 : 3; uint8_t c : 1; // 1 = Command, 0 = Control uint8_t command; uint8_t featurel; // DW1 uint8_t lba0, lba1, lba2; uint8_t device; // DW2 uint8_t lba3, lba4, lba5; uint8_t featureh; // DW3 uint8_t countl, counth; uint8_t icc; uint8_t control; // DW4 uint8_t rsv1[4]; } FIS_REG_H2D; // Register FIS - Device to Host (D2H) typedef struct { uint8_t fis_type; uint8_t pmport : 4; uint8_t rsv0 : 2; uint8_t i : 1; uint8_t rsv1 : 1; uint8_t status; uint8_t error; uint8_t lba0, lba1, lba2; uint8_t device; uint8_t lba3, lba4, lba5; uint8_t rsv2; uint8_t countl, counth; uint8_t rsv3[2]; uint8_t rsv4[4]; } FIS_REG_D2H; // DMA Setup FIS typedef struct { uint8_t fis_type; uint8_t pmport : 4; uint8_t rsv0 : 1; uint8_t d : 1; uint8_t i : 1; uint8_t a : 1; uint8_t rsved[2]; uint64_t DMAbufferID; uint32_t rsvd; uint32_t DMAbufOffset; uint32_t TransferCount; uint32_t resvd; } FIS_DMA_SETUP; // PIO Setup FIS typedef struct { uint8_t fis_type; uint8_t pmport : 4; uint8_t rsv0 : 1; uint8_t d : 1; uint8_t i : 1; uint8_t rsv1 : 1; uint8_t status; uint8_t error; uint8_t lba0, lba1, lba2; uint8_t device; uint8_t lba3, lba4, lba5; uint8_t rsv2; uint8_t countl, counth; uint8_t rsv3; uint8_t e_status; uint16_t tc; uint8_t rsv4[2]; } FIS_PIO_SETUP; // Set Device Bits FIS typedef struct { uint8_t fis_type; uint8_t pmport : 4; uint8_t rsv0 : 2; uint8_t i : 1; uint8_t n : 1; uint8_t statusl : 4; uint8_t rsv1 : 4; uint8_t statush : 4; uint8_t rsv2 : 4; uint8_t error; uint32_t protocol; } FIS_DEV_BITS; // --------------------------------------------------------------------------- // HBA structures (volatile - MMIO) // --------------------------------------------------------------------------- // Received FIS structure in host memory typedef volatile struct { FIS_DMA_SETUP dsfis; // 0x00 DMA Setup FIS uint8_t pad0[4]; FIS_PIO_SETUP psfis; // 0x20 PIO Setup FIS uint8_t pad1[12]; FIS_REG_D2H rfis; // 0x40 Register D2H FIS uint8_t pad2[4]; FIS_DEV_BITS sdbfis; // 0x58 Set Device Bits FIS uint8_t ufis[64]; // 0x60 Unknown FIS uint8_t rsv[0x100-0xA0]; } HBA_FIS; // Command List header (one entry = one slot) typedef struct { // DW0 uint8_t cfl : 5; // Command FIS length in DWORDs (2..16) uint8_t a : 1; // ATAPI uint8_t w : 1; // Write (H2D=1, D2H=0) uint8_t p : 1; // Prefetchable uint8_t r : 1; // Reset uint8_t b : 1; // BIST uint8_t c : 1; // Clear busy on R_OK uint8_t rsv0 : 1; uint8_t pmp : 4; // Port multiplier port uint16_t prdtl; // PRDT length in entries // DW1 volatile uint32_t prdbc; // PRDT byte count transferred // DW2,3 uint32_t ctba; // Command table base address (128-byte aligned) uint32_t ctbau; // Upper 32 bits // DW4-7 uint32_t rsv1[4]; } HBA_CMD_HEADER; // Physical Region Descriptor Table entry typedef struct { uint32_t dba; // Data base address uint32_t dbau; // Upper 32 bits uint32_t rsv0; uint32_t dbc : 22; // Byte count (0-based, so actual = dbc+1) uint32_t rsv1 : 9; uint32_t i : 1; // Interrupt on completion } HBA_PRDT_ENTRY; // Command Table typedef struct { uint8_t cfis[64]; // Command FIS (up to 64 bytes) uint8_t acmd[16]; // ATAPI command (12 or 16 bytes) uint8_t rsv[48]; // Reserved HBA_PRDT_ENTRY prdt_entry[1]; // PRDT entries (variable length) } HBA_CMD_TBL; #pragma pack(pop) // Port registers typedef volatile struct { uint32_t clb; // 0x00 Command list base (1K-aligned) uint32_t clbu; // 0x04 Command list base upper uint32_t fb; // 0x08 FIS base (256-byte aligned) uint32_t fbu; // 0x0C FIS base upper uint32_t is; // 0x10 Interrupt status uint32_t ie; // 0x14 Interrupt enable uint32_t cmd; // 0x18 Command and status uint32_t rsv0; // 0x1C Reserved uint32_t tfd; // 0x20 Task file data uint32_t sig; // 0x24 Signature uint32_t ssts; // 0x28 SATA status uint32_t sctl; // 0x2C SATA control uint32_t serr; // 0x30 SATA error uint32_t sact; // 0x34 SATA active uint32_t ci; // 0x38 Command issue uint32_t sntf; // 0x3C SATA notification uint32_t fbs; // 0x40 FIS-based switch control uint32_t rsv1[11]; uint32_t vendor[4]; } HBA_PORT; // Generic Host Control registers (starts at ABAR) typedef volatile struct { uint32_t cap; // 0x00 Host capability uint32_t ghc; // 0x04 Global host control uint32_t is; // 0x08 Interrupt status uint32_t pi; // 0x0C Ports implemented uint32_t vs; // 0x10 Version uint32_t ccc_ctl; // 0x14 CCC control uint32_t ccc_pts; // 0x18 CCC ports uint32_t em_loc; // 0x1C Enclosure mgmt location uint32_t em_ctl; // 0x20 Enclosure mgmt control uint32_t cap2; // 0x24 Extended capabilities uint32_t bohc; // 0x28 BIOS/OS handoff control uint8_t rsv[0xA0-0x2C]; uint8_t vendor[0x100-0xA0]; HBA_PORT ports[32]; // 0x100 Port control registers } HBA_MEM; // --------------------------------------------------------------------------- // Constants // --------------------------------------------------------------------------- // PCI #define PCI_AHCI_CLASS 0x01 #define PCI_AHCI_SUBCLASS 0x06 #define PCI_CMD_REG 0x04 #define PCI_BAR5_REG 0x24 #define PCI_CMD_BUSMASTER (1 << 2) #define PCI_CMD_MEMSPACE (1 << 1) // GHC register bits #define GHC_AE (1u << 31) // AHCI Enable #define GHC_IE (1u << 1) // Interrupt Enable #define GHC_HR (1u << 0) // HBA Reset // BOHC register bits #define BOHC_BOS (1u << 0) // BIOS-owned semaphore #define BOHC_OOS (1u << 1) // OS-owned semaphore #define BOHC_BB (1u << 4) // BIOS Busy // CAP2 bits #define CAP2_BOH (1u << 0) // BIOS/OS handoff capable // Port CMD register bits #define PORT_CMD_ST (1u << 0) // Start #define PORT_CMD_FRE (1u << 4) // FIS Receive Enable #define PORT_CMD_FR (1u << 14) // FIS Receive Running #define PORT_CMD_CR (1u << 15) // Command List Running #define PORT_CMD_POD (1u << 2) // Power On Device #define PORT_CMD_SUD (1u << 1) // Spin-Up Device #define PORT_CMD_ICC_ACTIVE (0x1u << 28) // Port IS register bits (interrupt status) #define PORT_IS_TFES (1u << 30) // Task File Error Status #define PORT_IS_HBFS (1u << 29) // Host Bus Fatal Error #define PORT_IS_HBDS (1u << 28) // Host Bus Data Error #define PORT_IS_IFS (1u << 27) // Interface Fatal Error // Port SSTS register #define PORT_DET_PRESENT 0x3 #define PORT_IPM_ACTIVE 0x1 // Port signatures #define SATA_SIG_ATA 0x00000101 #define SATA_SIG_ATAPI 0xEB140101 #define SATA_SIG_SEMB 0xC33C0101 #define SATA_SIG_PM 0x96690101 // ATA commands #define ATA_CMD_READ_DMA_EX 0x25 #define ATA_CMD_WRITE_DMA_EX 0x35 #define ATA_CMD_IDENTIFY 0xEC #define ATA_CMD_FLUSH_EXT 0xEA // ATA status bits #define ATA_SR_BUSY 0x80 #define ATA_SR_DRQ 0x08 #define ATA_SR_ERR 0x01 // IDENTIFY word offsets #define ATA_IDENT_W83 83 // bit 10 = 48-bit LBA supported #define ATA_IDENT_W100 100 // 48-bit LBA sector count (4 words) #define ATA_IDENT_W60 60 // 28-bit LBA sector count (2 words) // Layout constants (per port, single contiguous physical allocation) // Offset 0: Command List 1024 bytes (32 × 32-byte headers) // Offset 1024: Received FIS 256 bytes // Offset 2048: Command Tables 32 × 256 bytes = 8192 bytes // Total: 10240 bytes → 3 pages (12288 bytes) #define PORT_PAGES_STRUCT 3 #define PORT_OFF_CMDLIST 0 #define PORT_OFF_FIS 1024 #define PORT_OFF_CMDTBLS 2048 #define PORT_CMDTBL_SIZE 256 // 64 CFIS + 16 ACMD + 48 rsv + 8×16 PRDT #define PORT_PRDT_COUNT 8 // PRDT entries per command table // Bounce buffer: 128 sectors × 512 bytes = 64 KB = 16 pages #define BOUNCE_SECTORS 128 #define BOUNCE_BYTES (BOUNCE_SECTORS * 512) #define BOUNCE_PAGES (BOUNCE_BYTES / 4096) // Polling timeout (spin iterations) #define POLL_TIMEOUT 1000000 #define MAX_AHCI_DRIVES 8 #define NUM_CMD_SLOTS 32 // Map MMIO physical range into the physical window as uncacheable. // Must be called before any pointer dereference via PhysToVirt(). // AHCI MMIO layout: 0x100 GHC + 32*0x80 ports = 0x1100 bytes → 2 pages minimum. // We map 8 pages (32KB) without probing the BAR size. #define AHCI_MMIO_PAGES 8 // --------------------------------------------------------------------------- // Driver-global state // --------------------------------------------------------------------------- static const HAL_API *g_hal; static HBA_MEM *g_hba; // HBA MMIO base (set during init) static uint8_t g_irq; // PCI IRQ line for this HBA static DRIVER_OBJECT g_driver; // AHCI disk driver object // Per-drive context typedef struct { HBA_PORT *port; // MMIO port registers (virtual) uint64_t sectorCount; // Total LBA sectors on device uint8_t portNo; // Physical port index (for ISR dispatch) // Structures block (command list + FIS + cmd tables) uint64_t structPhys; // Physical base void *structVirt; // Virtual base // Bounce buffer for DMA data uint64_t bouncePhys; void *bounceVirt; // Signaled by the completion DPC when the port raises an interrupt. // Auto-reset: one Wait consumes one completion. EVENT *completionEvent; // Last IS snapshot captured by the ISR (for error checking post-wait). volatile uint32_t lastIs; // Bottom-half used to wake the worker outside hard IRQ/DIRQL context. KDPC completionDpc; // ----------------------------------------------------------------------- // IRP queue - async dispatch // ----------------------------------------------------------------------- // AhciWorker blocks here waiting for work. AHCI dispatch enqueues an IRP // and signals the semaphore to wake the worker. IRP_QUEUE irpQueue; THREAD *workerThread; DEVICE_OBJECT *deviceObject; // NCQ TODO: for multi-slot NCQ, add: // uint32_t slotMask; // bitmask of in-flight slots // IRP *slotIrp[NUM_CMD_SLOTS]; // slot → pending IRP // uint64_t slotBouncePhys[NUM_CMD_SLOTS]; // void *slotBounceVirt[NUM_CMD_SLOTS]; // volatile uint32_t prevSact; // previous port->sact snapshot } AHCI_DRIVE; static AHCI_DRIVE g_drives[MAX_AHCI_DRIVES]; static int g_driveCount; // --------------------------------------------------------------------------- // Helpers // --------------------------------------------------------------------------- static KSTATUS ahci_map_mmio(uint64_t physBase) { for (int i = 0; i < AHCI_MMIO_PAGES; i++) { uint64_t phys = physBase + (uint64_t)i * 4096; uintptr_t virt = (uintptr_t)g_hal->PhysToVirt(phys); uint64_t flags = PAGE_PRESENT | PAGE_WRITE | PAGE_NOCACHE; KSTATUS st = MmMapPage(virt, phys, flags); // Ignore STATUS_ALREADY_EXISTS - a prior mapping with different flags // is possible for the first page if the bootloader was overly generous. // Use MmSetPageProtect to force NOCACHE in that case. if (st == STATUS_ALREADY_EXISTS) { st = MmSetPageProtect(virt, 4096, flags); } if (!KSUCCESS(st)) { DbgPrint("AHCI: MmMapPage failed for page %d (phys=0x%llx, st=0x%x)\n", i, (unsigned long long)phys, st); return st; } } return STATUS_SUCCESS; } // Accessors for port structure memory at known offsets from structVirt/Phys static inline HBA_CMD_HEADER *cmd_list(AHCI_DRIVE *drv) { return (HBA_CMD_HEADER *)((uint8_t *)drv->structVirt + PORT_OFF_CMDLIST); } static inline uint64_t cmd_list_phys(AHCI_DRIVE *drv) { return drv->structPhys + PORT_OFF_CMDLIST; } static inline uint64_t fis_phys(AHCI_DRIVE *drv) { return drv->structPhys + PORT_OFF_FIS; } static inline HBA_CMD_TBL *cmd_tbl(AHCI_DRIVE *drv, int slot) { return (HBA_CMD_TBL *)((uint8_t *)drv->structVirt + PORT_OFF_CMDTBLS + (uint32_t)slot * PORT_CMDTBL_SIZE); } static inline uint64_t cmd_tbl_phys(AHCI_DRIVE *drv, int slot) { return drv->structPhys + PORT_OFF_CMDTBLS + (uint64_t)slot * PORT_CMDTBL_SIZE; } // --------------------------------------------------------------------------- // Port engine start / stop (polling safe) // --------------------------------------------------------------------------- static void port_stop(HBA_PORT *port) { // Clear ST (bit 0) port->cmd &= ~PORT_CMD_ST; // Wait for CR (bit 15) to clear (command list DMA stops) for (int i = 0; i < POLL_TIMEOUT; i++) { if (!(port->cmd & PORT_CMD_CR)) break; } // Clear FRE (bit 4) port->cmd &= ~PORT_CMD_FRE; // Wait for FR (bit 14) to clear for (int i = 0; i < POLL_TIMEOUT; i++) { if (!(port->cmd & PORT_CMD_FR)) break; } } static void port_start(HBA_PORT *port) { // Wait until CR is clear before setting ST for (int i = 0; i < POLL_TIMEOUT; i++) { if (!(port->cmd & PORT_CMD_CR)) break; } port->cmd |= PORT_CMD_FRE; port->cmd |= PORT_CMD_ST; } // --------------------------------------------------------------------------- // Port memory initialisation // --------------------------------------------------------------------------- static KSTATUS port_init_memory(AHCI_DRIVE *drv) { uint64_t flags = PAGE_PRESENT | PAGE_WRITE | PAGE_NOCACHE; drv->structPhys = MmAllocateContiguous(PORT_PAGES_STRUCT); if (!drv->structPhys) return STATUS_NO_MEMORY; drv->structVirt = g_hal->PhysToVirt(drv->structPhys); // Force NOCACHE on DMA descriptor memory MmSetPageProtect((uintptr_t)drv->structVirt, PORT_PAGES_STRUCT * 4096, flags); memset(drv->structVirt, 0, PORT_PAGES_STRUCT * 4096); drv->bouncePhys = MmAllocateContiguous(BOUNCE_PAGES); if (!drv->bouncePhys) return STATUS_NO_MEMORY; drv->bounceVirt = g_hal->PhysToVirt(drv->bouncePhys); // Bounce buffer: NOCACHE to ensure CPU writes reach physical memory // before the HBA's DMA engine reads them MmSetPageProtect((uintptr_t)drv->bounceVirt, BOUNCE_PAGES * 4096, flags); memset(drv->bounceVirt, 0, BOUNCE_BYTES); HBA_PORT *port = drv->port; port_stop(port); // Set command list base port->clb = (uint32_t)(cmd_list_phys(drv) & 0xFFFFFFFF); port->clbu = (uint32_t)(cmd_list_phys(drv) >> 32); // Set FIS base port->fb = (uint32_t)(fis_phys(drv) & 0xFFFFFFFF); port->fbu = (uint32_t)(fis_phys(drv) >> 32); // Initialise all 32 command headers, pointing each to its command table HBA_CMD_HEADER *hdrs = cmd_list(drv); for (int i = 0; i < NUM_CMD_SLOTS; i++) { hdrs[i].prdtl = PORT_PRDT_COUNT; uint64_t tbl = cmd_tbl_phys(drv, i); hdrs[i].ctba = (uint32_t)(tbl & 0xFFFFFFFF); hdrs[i].ctbau = (uint32_t)(tbl >> 32); } // Clear any stale interrupts then start the port engine port->serr = (uint32_t)-1; port->is = (uint32_t)-1; port_start(port); return STATUS_SUCCESS; } // --------------------------------------------------------------------------- // Issue a command - polling fallback (used during early init / IDENTIFY only, // before the scheduler and interrupt handler are live). // Returns STATUS_SUCCESS, STATUS_DEVICE_ERROR, or STATUS_TIMEOUT. // --------------------------------------------------------------------------- static KSTATUS port_issue_cmd_poll(AHCI_DRIVE *drv) { HBA_PORT *port = drv->port; // Clear pending interrupts before issuing port->is = (uint32_t)-1; // Wait for port to be idle (not BSY or DRQ) int spin = 0; while ((port->tfd & (ATA_SR_BUSY | ATA_SR_DRQ)) && spin < POLL_TIMEOUT) spin++; if (spin == POLL_TIMEOUT) { DbgPrint("AHCI: port hung (pre-issue)\n"); return STATUS_TIMEOUT; } // Issue slot 0 port->ci = (1u << 0); // Poll until slot 0 clears while (true) { if (!(port->ci & (1u << 0))) break; if (port->is & (PORT_IS_TFES | PORT_IS_HBFS | PORT_IS_HBDS | PORT_IS_IFS)) { DbgPrint("AHCI: error IS=0x%x TFD=0x%x SERR=0x%x\n", port->is, port->tfd, port->serr); port->serr = (uint32_t)-1; port->is = (uint32_t)-1; return STATUS_DEVICE_ERROR; } } if (port->is & PORT_IS_TFES) { DbgPrint("AHCI: TFES after completion TFD=0x%x\n", port->tfd); port->is = (uint32_t)-1; return STATUS_DEVICE_ERROR; } return STATUS_SUCCESS; } // --------------------------------------------------------------------------- // Interrupt bottom half. The ISR owns hardware acknowledgement and status // capture; this DPC wakes the worker thread after the hard IRQ has unwound. // --------------------------------------------------------------------------- static void AhciCompletionDpc(KDPC *dpc, void *context, void *systemArgument1, void *systemArgument2) { (void)dpc; (void)systemArgument1; (void)systemArgument2; AHCI_DRIVE *drv = (AHCI_DRIVE *)context; if (drv && drv->completionEvent) KeSignalEvent(drv->completionEvent); } // --------------------------------------------------------------------------- // ISR - called from KeIrqDispatch on the AHCI PCI IRQ line. // Walks all registered drives, checks if their port raised an interrupt, // captures IS, clears it, and queues the per-drive completion DPC. // --------------------------------------------------------------------------- static void AhciIsr(void) { if (!g_hba) return; // GHC.IS tells us which ports are pending. uint32_t pending = g_hba->is; if (!pending) return; for (int i = 0; i < g_driveCount; i++) { AHCI_DRIVE *drv = &g_drives[i]; uint32_t portBit = (1u << drv->portNo); if (!(pending & portBit)) continue; // Capture and clear port IS before queueing the bottom half. The // waiter reads lastIs to check for errors without racing the next // command. OR in case hardware reports multiple causes before the // DPC releases the worker. uint32_t portIs = drv->port->is; drv->port->is = portIs; // W1C - write back to clear drv->lastIs |= portIs; // Clear the HBA-level bit. g_hba->is = portBit; KeInsertQueueDpc(&drv->completionDpc, (void *)0, (void *)0); } } // --------------------------------------------------------------------------- // Issue a command - interrupt-driven (runtime path). // Caller has already built slot 0 via build_rw_cmd / port_identify. // Blocks the current thread until the ISR signals completionEvent. // --------------------------------------------------------------------------- static KSTATUS port_issue_cmd(AHCI_DRIVE *drv) { HBA_PORT *port = drv->port; // Clear stale IS and snapshot before issuing so we don't mis-read a // leftover value from a prior command. port->is = (uint32_t)-1; drv->lastIs = 0; // Wait for port idle int spin = 0; while ((port->tfd & (ATA_SR_BUSY | ATA_SR_DRQ)) && spin < POLL_TIMEOUT) spin++; if (spin == POLL_TIMEOUT) { DbgPrint("AHCI: port hung (pre-issue)\n"); return STATUS_TIMEOUT; } // Issue slot 0, then block on the event. port->ci = (1u << 0); KeWaitForEvent(drv->completionEvent, 0); // The ISR has cleared IS - check for errors in the snapshot. uint32_t is = drv->lastIs; if (is & (PORT_IS_TFES | PORT_IS_HBFS | PORT_IS_HBDS | PORT_IS_IFS)) { DbgPrint("AHCI: error IS=0x%x TFD=0x%x SERR=0x%x\n", is, port->tfd, port->serr); port->serr = (uint32_t)-1; return STATUS_DEVICE_ERROR; } return STATUS_SUCCESS; } // --------------------------------------------------------------------------- // Build a standard DMA read or write command in slot 0 // --------------------------------------------------------------------------- static void build_rw_cmd(AHCI_DRIVE *drv, uint64_t lba, uint32_t sectors, uint64_t bufPhys, bool write) { HBA_CMD_HEADER *hdr = cmd_list(drv); // slot 0 HBA_CMD_TBL *tbl = cmd_tbl(drv, 0); memset(tbl, 0, PORT_CMDTBL_SIZE); // How many PRDT entries we need (each covers up to 8K = 16 sectors) uint32_t prdtl = (sectors + 15) / 16; if (prdtl > PORT_PRDT_COUNT) prdtl = PORT_PRDT_COUNT; // capped (see caller) hdr->cfl = sizeof(FIS_REG_H2D) / 4; hdr->w = write ? 1 : 0; hdr->prdtl = (uint16_t)prdtl; hdr->prdbc = 0; // Fill PRDT entries uint32_t remaining = sectors; uint64_t buf = bufPhys; for (uint32_t i = 0; i < prdtl; i++) { uint32_t sects = (remaining > 16) ? 16 : remaining; uint32_t bytes = sects * 512; tbl->prdt_entry[i].dba = (uint32_t)(buf & 0xFFFFFFFF); tbl->prdt_entry[i].dbau = (uint32_t)(buf >> 32); tbl->prdt_entry[i].dbc = bytes - 1; // hardware adds 1 tbl->prdt_entry[i].i = (i == prdtl - 1) ? 1 : 0; buf += bytes; remaining -= sects; } // Build H2D FIS FIS_REG_H2D *fis = (FIS_REG_H2D *)tbl->cfis; memset(fis, 0, sizeof(*fis)); fis->fis_type = FIS_TYPE_REG_H2D; fis->c = 1; fis->command = write ? ATA_CMD_WRITE_DMA_EX : ATA_CMD_READ_DMA_EX; fis->device = 1u << 6; // LBA mode fis->lba0 = (uint8_t)(lba); fis->lba1 = (uint8_t)(lba >> 8); fis->lba2 = (uint8_t)(lba >> 16); fis->lba3 = (uint8_t)(lba >> 24); fis->lba4 = (uint8_t)(lba >> 32); fis->lba5 = (uint8_t)(lba >> 40); fis->countl = (uint8_t)(sectors & 0xFF); fis->counth = (uint8_t)(sectors >> 8); } // --------------------------------------------------------------------------- // IDENTIFY command - fills a 512-byte buffer and returns it // --------------------------------------------------------------------------- static KSTATUS port_identify(AHCI_DRIVE *drv) { // Reuse bounce buffer for IDENTIFY data (512 bytes) memset(drv->bounceVirt, 0, 512); HBA_CMD_HEADER *hdr = cmd_list(drv); HBA_CMD_TBL *tbl = cmd_tbl(drv, 0); memset(tbl, 0, PORT_CMDTBL_SIZE); hdr->cfl = sizeof(FIS_REG_H2D) / 4; hdr->w = 0; hdr->prdtl = 1; hdr->prdbc = 0; tbl->prdt_entry[0].dba = (uint32_t)(drv->bouncePhys & 0xFFFFFFFF); tbl->prdt_entry[0].dbau = (uint32_t)(drv->bouncePhys >> 32); tbl->prdt_entry[0].dbc = 512 - 1; tbl->prdt_entry[0].i = 1; FIS_REG_H2D *fis = (FIS_REG_H2D *)tbl->cfis; memset(fis, 0, sizeof(*fis)); fis->fis_type = FIS_TYPE_REG_H2D; fis->c = 1; fis->command = ATA_CMD_IDENTIFY; fis->device = 0; // Poll: IDENTIFY runs before the scheduler and IRQ handler are live. KSTATUS st = port_issue_cmd_poll(drv); if (!KSUCCESS(st)) return st; // Parse sector count from IDENTIFY data const uint16_t *id = (const uint16_t *)drv->bounceVirt; if (id[ATA_IDENT_W83] & (1u << 10)) { // 48-bit LBA supported drv->sectorCount = (uint64_t)id[ATA_IDENT_W100] | ((uint64_t)id[ATA_IDENT_W100 + 1] << 16) | ((uint64_t)id[ATA_IDENT_W100 + 2] << 32) | ((uint64_t)id[ATA_IDENT_W100 + 3] << 48); } else { // 28-bit LBA drv->sectorCount = (uint64_t)id[ATA_IDENT_W60] | ((uint64_t)id[ATA_IDENT_W60 + 1] << 16); } return STATUS_SUCCESS; } // Core read logic static KSTATUS do_read(AHCI_DRIVE *drv, uint64_t lba, uint32_t count, void *buf) { uint8_t *out = (uint8_t *)buf; while (count > 0) { uint32_t batch = (count > BOUNCE_SECTORS) ? BOUNCE_SECTORS : count; build_rw_cmd(drv, lba, batch, drv->bouncePhys, false); KSTATUS st = port_issue_cmd(drv); if (!KSUCCESS(st)) return st; memcpy(out, drv->bounceVirt, (size_t)batch * 512); out += (size_t)batch * 512; lba += batch; count -= batch; } return STATUS_SUCCESS; } // Core write logic static KSTATUS do_write(AHCI_DRIVE *drv, uint64_t lba, uint32_t count, const void *buf) { const uint8_t *in = (const uint8_t *)buf; while (count > 0) { uint32_t batch = (count > BOUNCE_SECTORS) ? BOUNCE_SECTORS : count; memcpy(drv->bounceVirt, in, (size_t)batch * 512); build_rw_cmd(drv, lba, batch, drv->bouncePhys, true); KSTATUS st = port_issue_cmd(drv); if (!KSUCCESS(st)) return st; in += (size_t)batch * 512; lba += batch; count -= batch; } return STATUS_SUCCESS; } // --------------------------------------------------------------------------- // Async IRP dispatch // --------------------------------------------------------------------------- // AhciDispatchReadWrite - DEVICE_OBJECT dispatch entry for disk IRPs. // Accepted IRPs are queued to the per-drive worker and completed later with // IoCompleteRequest(). Rejected IRPs are returned synchronously and are not // completed. static KSTATUS AhciDispatchReadWrite(DEVICE_OBJECT *device, IRP *irp) { if (!device || !irp) return STATUS_INVALID_PARAMETER; AHCI_DRIVE *drv = (AHCI_DRIVE *)device->DeviceExtension; if (!drv) return STATUS_INVALID_PARAMETER; if (irp->SectorCount == 0 || !irp->Buffer) return STATUS_INVALID_PARAMETER; if (irp->Lba + irp->SectorCount > drv->sectorCount) return STATUS_INVALID_PARAMETER; irp->Status = STATUS_FAILURE; irp->Information = 0; IrpQueueEnqueue(&drv->irpQueue, irp); return STATUS_PENDING; } // AhciWorker - kernel thread, one per drive. // Dequeues IRPs and executes them one at a time using the existing // single-slot interrupt-driven path. Completion fires the IRP's event // and/or callback so the original caller can observe the result without // ever having blocked in a driver call. // // NCQ TODO: replace the serialised loop with a multi-slot dispatcher: // 1. KeWaitSemaphore() to wait for a free slot AND a pending IRP. // 2. Pick the oldest IRP from the queue. // 3. Grab a free bit in drv->slotMask (under the slot spinlock). // 4. Copy write data into slotBounce[slot], build the NCQ FIS (FPDMA), // record slotIrp[slot] = irp, and issue via port->sact + port->ci. // 5. Return immediately - the ISR drives all completions. static void AhciWorker(uintptr_t arg) { AHCI_DRIVE *drv = (AHCI_DRIVE *)arg; while (true) { // Block until AHCI dispatch signals a new IRP. KeWaitSemaphore(drv->irpQueue.Semaphore); IRP *irp = IrpQueueDequeue(&drv->irpQueue); if (!irp) KePanic("AhciWorker: semaphore fired but queue is empty - IRP accounting bug\n"); bool write = !!(irp->Flags & IRP_FLAG_WRITE); KSTATUS st; if (write) st = do_write(drv, irp->Lba, irp->SectorCount, irp->Buffer); else st = do_read (drv, irp->Lba, irp->SectorCount, irp->Buffer); // Publish result then fire completion hooks through the common I/O path. IoCompleteRequest(irp, st, KSUCCESS(st) ? ((size_t)irp->SectorCount * 512u) : 0); } } // --------------------------------------------------------------------------- // AHCI controller initialisation // --------------------------------------------------------------------------- static KSTATUS hba_reset(HBA_MEM *hba) { // BIOS/OS handoff (spec §10.6.3) if (hba->cap2 & CAP2_BOH) { hba->bohc |= BOHC_OOS; // Wait for BIOS to clear BOS for (int i = 0; i < POLL_TIMEOUT; i++) { if (!(hba->bohc & BOHC_BOS)) break; } // Give the BIOS another moment to clear Busy for (int i = 0; i < 800000; i++) { if (!(hba->bohc & BOHC_BB)) break; } } // Enable AHCI mode before reset so the reset actually takes effect hba->ghc |= GHC_AE; // HBA reset hba->ghc |= GHC_HR; for (int i = 0; i < POLL_TIMEOUT; i++) { if (!(hba->ghc & GHC_HR)) break; } if (hba->ghc & GHC_HR) { DbgPrint("AHCI: HBA reset timed out\n"); return STATUS_TIMEOUT; } // Re-enable AHCI mode (reset cleared it), then enable global interrupts. // GHC.IE lets the HBA assert its PCI interrupt line when a port fires. hba->ghc |= GHC_AE | GHC_IE; return STATUS_SUCCESS; } // Before memory init: only check physical link. Signature is not yet valid. static bool port_link_up(HBA_PORT *port) { uint32_t det = port->ssts & 0x0F; uint32_t ipm = (port->ssts >> 8) & 0x0F; return (det == PORT_DET_PRESENT && ipm == PORT_IPM_ACTIVE); } // After COMRESET + FIS receive: check signature for SATA disk. static bool port_is_sata_disk(HBA_PORT *port) { return port->sig == SATA_SIG_ATA; } static void ahci_delay_ms(uint32_t ms) { for (uint32_t i = 0; i < ms * 1000; i++) __outbyte(0x80, 0); } // Issue a COMRESET on the port, wait for link re-establishment and D2H FIS. // FRE must already be set (port_init_memory does this) so the HBA can // capture the signature FIS the device sends after the reset. static KSTATUS port_comreset(AHCI_DRIVE *drv) { HBA_PORT *port = drv->port; port->cmd &= ~PORT_CMD_ST; for (int i = 0; i < POLL_TIMEOUT; i++) if (!(port->cmd & PORT_CMD_CR)) break; // Assert COMRESET: SControl.DET = 1, hold for ≥ 1ms port->sctl = (port->sctl & ~0x0Fu) | 0x1u; ahci_delay_ms(1); // Deassert: DET = 0 port->sctl = port->sctl & ~0x0Fu; // Poll for DET = 3, up to 1 second bool link_ok = false; for (int i = 0; i < 1000; i++) { if ((port->ssts & 0x0Fu) == PORT_DET_PRESENT) { link_ok = true; break; } ahci_delay_ms(1); } if (!link_ok) { DbgPrint("AHCI: COMRESET: link did not come back (ssts=0x%x)\n", port->ssts); return STATUS_TIMEOUT; } port->serr = (uint32_t)-1; port->is = (uint32_t)-1; port->cmd |= PORT_CMD_ST; // Wait up to 500ms for a valid signature (D2H FIS from device) for (int i = 0; i < 500; i++) { uint32_t sig = port->sig; if (sig != 0xFFFFFFFFu && sig != 0x00000000u) break; ahci_delay_ms(1); } DbgPrint("AHCI: port COMRESET done: sig=0x%08x ssts=0x%08x\n", port->sig, port->ssts); return STATUS_SUCCESS; } // PORT_IE bits we care about: // DHRS (bit 0) - D2H Register FIS received - normal completion // PSS (bit 1) - PIO Setup FIS received // DSS (bit 2) - DMA Setup FIS received // SDBS (bit 3) - Set Device Bits FIS received // TFES (bit 30) - Task File Error Status - error // HBFS (bit 29) - Host Bus Fatal error // HBDS (bit 28) - Host Bus Data error // IFS (bit 27) - Interface Fatal error #define PORT_IE_NORMAL (0x0000000Fu) #define PORT_IE_ERRORS (PORT_IS_TFES | PORT_IS_HBFS | PORT_IS_HBDS | PORT_IS_IFS) #define PORT_IE_ALL (PORT_IE_NORMAL | PORT_IE_ERRORS) KSTATUS AhciInitialize(const HAL_API *hal) { g_hal = hal; g_driveCount = 0; memset(&g_driver, 0, sizeof(g_driver)); g_driver.Name = "ahci"; g_driver.MajorFunction[IRP_MJ_READ] = AhciDispatchReadWrite; g_driver.MajorFunction[IRP_MJ_WRITE] = AhciDispatchReadWrite; // ----------------------------------------------------------------------- // Locate AHCI controller via PCI class scan // ----------------------------------------------------------------------- uint8_t pciBus, pciDev, pciFn; if (!hal->Pci.FindClass(PCI_AHCI_CLASS, PCI_AHCI_SUBCLASS, &pciBus, &pciDev, &pciFn)) { DbgPrint("AHCI: no AHCI controller found\n"); return STATUS_NOT_FOUND; } DbgPrint("AHCI: controller at PCI %02x:%02x.%x\n", pciBus, pciDev, pciFn); // ----------------------------------------------------------------------- // Enable Bus Master + Memory Space in PCI command register // ----------------------------------------------------------------------- uint32_t cmd = hal->Pci.Read32(pciBus, pciDev, pciFn, PCI_CMD_REG); cmd |= (PCI_CMD_BUSMASTER | PCI_CMD_MEMSPACE); cmd &= ~(1 << 10); cmd |= (1 << 2); hal->Pci.Write32(pciBus, pciDev, pciFn, PCI_CMD_REG, cmd); // ----------------------------------------------------------------------- // Read PCI IRQ line // ----------------------------------------------------------------------- g_irq = hal->Pci.GetIrqLine(pciBus, pciDev, pciFn); if (g_irq == 0xFF) { DbgPrint("AHCI: no PCI IRQ wired - cannot use interrupt-driven mode\n"); return STATUS_NOT_SUPPORTED; } DbgPrint("AHCI: PCI IRQ line = %u\n", (unsigned)g_irq); // ----------------------------------------------------------------------- // Read ABAR (BAR5) and map as uncacheable // ----------------------------------------------------------------------- uint32_t bar5 = hal->Pci.Read32(pciBus, pciDev, pciFn, PCI_BAR5_REG); uint64_t abarPhys = (uint64_t)(bar5 & ~0xFFFu); KSTATUS st = ahci_map_mmio(abarPhys); if (!KSUCCESS(st)) return st; g_hba = (HBA_MEM *)hal->PhysToVirt(abarPhys); DbgPrint("AHCI: ABAR phys=0x%llx version=0x%08x\n", (unsigned long long)abarPhys, g_hba->vs); // ----------------------------------------------------------------------- // HBA reset + BIOS handoff (also enables GHC.IE) // ----------------------------------------------------------------------- st = hba_reset(g_hba); if (!KSUCCESS(st)) return st; // ----------------------------------------------------------------------- // Log capability summary // ----------------------------------------------------------------------- uint32_t cap = g_hba->cap; uint32_t nPorts = (cap & 0x1F) + 1; uint32_t nSlots = ((cap >> 8) & 0x1F) + 1; bool s64a = !!(cap & (1u << 31)); DbgPrint("AHCI: cap=0x%08x ports=%u slots=%u 64bit=%d\n", cap, nPorts, nSlots, (int)s64a); // ----------------------------------------------------------------------- // Enumerate implemented ports // ----------------------------------------------------------------------- uint32_t pi = g_hba->pi; for (uint32_t portno = 0; portno < 32 && g_driveCount < MAX_AHCI_DRIVES; portno++) { if (!(pi & (1u << portno))) continue; HBA_PORT *port = &g_hba->ports[portno]; // Phase 1: physical link check if (!port_link_up(port)) { DbgPrint("AHCI: port %u: no link (ssts=0x%08x)\n", portno, port->ssts); continue; } DbgPrint("AHCI: port %u: link up, initializing...\n", portno); int driveIdx = g_driveCount; AHCI_DRIVE *drv = &g_drives[driveIdx]; memset(drv, 0, sizeof(*drv)); drv->port = port; drv->portNo = (uint8_t)portno; // Phase 2: allocate command list, FIS buffer, bounce buffer st = port_init_memory(drv); if (!KSUCCESS(st)) { DbgPrint("AHCI: port %u: memory init failed (0x%x)\n", portno, st); continue; } // Phase 3: COMRESET - forces device to re-send D2H FIS for valid SIG st = port_comreset(drv); if (!KSUCCESS(st)) { DbgPrint("AHCI: port %u: COMRESET failed\n", portno); continue; } // Phase 4: filter to SATA disks if (!port_is_sata_disk(port)) { DbgPrint("AHCI: port %u: not a SATA disk (sig=0x%08x), skipping\n", portno, port->sig); continue; } // Phase 5: create per-drive completion event (auto-reset, initially clear) st = KeEventCreate(EventAutoReset, 0, &drv->completionEvent); if (!KSUCCESS(st)) { DbgPrint("AHCI: port %u: event create failed (0x%x)\n", portno, st); continue; } KeInitializeDpc(&drv->completionDpc, AhciCompletionDpc, drv); // Phase 5b: create the IRP queue semaphore and initialise the queue. // The semaphore starts at 0; each submitted IRP increments it by one. SEMAPHORE *irpSem = (SEMAPHORE *)0; st = KeSemaphoreCreate(0, 0x7FFFFFFF, &irpSem); if (!KSUCCESS(st)) { DbgPrint("AHCI: port %u: semaphore create failed (0x%x)\n", portno, st); continue; } IrpQueueInit(&drv->irpQueue, irpSem); // Phase 6: IDENTIFY (polled - scheduler not yet running) st = port_identify(drv); if (!KSUCCESS(st)) { DbgPrint("AHCI: port %u: IDENTIFY failed (0x%x)\n", portno, st); continue; } DbgPrint("AHCI: drive %d: %llu sectors (%llu MB)\n", driveIdx, (unsigned long long)drv->sectorCount, (unsigned long long)(drv->sectorCount / 2048)); // Phase 7: enable per-port interrupts. // Clear any stale IS first so we don't get a spurious signal immediately. port->is = (uint32_t)-1; port->ie = PORT_IE_ALL; // Phase 8: create and register a disk DEVICE_OBJECT. st = IoCreateDevice(&g_driver, 0, &drv->deviceObject); if (!KSUCCESS(st)) { DbgPrint("AHCI: drive %d: IoCreateDevice failed (0x%x)\n", driveIdx, st); continue; } drv->deviceObject->DeviceExtension = drv; drv->deviceObject->SectorCount = drv->sectorCount; drv->deviceObject->AlignmentRequirement = 512; st = IoRegisterDiskDevice((uint8_t)driveIdx, drv->deviceObject); if (KSUCCESS(st)) { DbgPrint("AHCI: drive %d registered\n", driveIdx); g_driveCount++; } else { DbgPrint("AHCI: IoRegisterDiskDevice(%d) failed (0x%x)\n", driveIdx, st); IoDeleteDevice(drv->deviceObject); drv->deviceObject = (DEVICE_OBJECT*)0; continue; } // Phase 9: spawn the per-drive IRP worker thread. // The worker owns do_read / do_write exclusively once the scheduler // is live; it is the only thread that may call port_issue_cmd(). st = KeCreateKernelThread((uintptr_t)AhciWorker, (uintptr_t)drv, PriorityHigh, &drv->workerThread); if (!KSUCCESS(st)) { DbgPrint("AHCI: drive %d: worker thread create failed (0x%x)\n", driveIdx, st); // Fatal for this device: all disk access is IRP-based now, so // leave the device registered but clearly fail during testing. } } if (g_driveCount == 0) { DbgPrint("AHCI: no drives found\n"); return STATUS_NOT_FOUND; } // ----------------------------------------------------------------------- // Register the ISR. All ports on this HBA share one PCI IRQ line. // Do this after all drives are initialised so the ISR sees valid state. // ----------------------------------------------------------------------- KeIrqRegister(g_irq, AhciIsr); DbgPrint("AHCI: ISR registered on IRQ %u; initialised %d drive(s)\n", (unsigned)g_irq, g_driveCount); return STATUS_SUCCESS; } KSTATUS DriverEntry(const HAL_API *hal) { DbgPrint("AHCI: driver loading...\n"); KSTATUS st = AhciInitialize(hal); if (!KSUCCESS(st)) DbgPrint("AHCI: init failed: 0x%x\n", st); return st; }