Robert Allan JamesandClaude Sonnet 5
6d330efdd8
xhci_poll_events()'s Port Status Change connect branch now calls xhci_cmd_enable_slot() directly (the earlier boot-time smoke test call is gone), tracked via a new dev->pending_connect_port_id -- since this driver only ever has one command outstanding at a time, that alone identifies which port a later Command Completion Event answers, without needing to match the Command TRB Pointer yet. On success the returned Slot ID is recorded in a new dev->port_slot_id[], a fixed uint32_t[XHCI_MAX_TRACKED_PORTS] (32) indexed by port. Disconnect clears the port's tracked slot (real teardown -- Disable Slot, DCBAA clear, Section U callback -- is still a later increment). Fixed array, not heap-allocated: a first attempt sized port_slot_id dynamically via kmalloc_aligned(dev->max_ports * sizeof(uint32_t), 64) inside xhci_bringup() and it crashed amd64 with a page fault (IFETCH at RIP=CR2=0xA0000, the legacy VGA hole) during the unrelated Mama-VM-birth phase afterward -- a heap-corruption signature, not chased to root cause. Switching to a fixed array (matching this driver's existing preference for fixed over dynamic allocation) made the crash go away; the crashing boot's log is kept (logs/20260822-102516/) as the evidence trail. Verified live via QMP hotplug, all three architectures: connect -> "enable slot command submitted" -> "enable slot succeeded", with a disconnect/reconnect cycle repeating cleanly and no port wedge. Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01HZ8kNoTuP63pbQtro4qvrm
141 lines
6.8 KiB
C
141 lines
6.8 KiB
C
/*
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* xhci_driver.h — xHCI USB host controller driver public API for StarKernel
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*
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* Register-layout definitions live in xhci.h; this header is the driver's
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* own state and public entry points, matching virtio_blk.h's split.
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*/
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#ifndef STARKERNEL_XHCI_DRIVER_H
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#define STARKERNEL_XHCI_DRIVER_H
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#include <stdint.h>
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#include "starkernel/pci.h"
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#include "starkernel/xhci.h"
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/* Driver state for one xHCI controller instance. Only one controller is
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* supported (matches virtio_blk's single-device precedent). */
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typedef struct {
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PciDevice pci;
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uint64_t bar0_phys; /* physical MMIO base, BAR0 */
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xhci_cap_regs_t *cap; /* BAR0 + 0 */
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xhci_op_regs_t *op; /* BAR0 + cap->cap_length */
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xhci_runtime_regs_t *runtime; /* BAR0 + cap->rts_off */
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xhci_doorbell_t *doorbell; /* BAR0 + cap->db_off */
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uint32_t max_slots;
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uint32_t max_ports;
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uint32_t max_intrs;
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uint32_t max_scratchpad_bufs;
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/* Set up by xhci_bringup(); NULL/0 until then. */
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void *dcbaa; /* Device Context Base Address Array */
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void *scratchpad_arr; /* array of scratchpad buffer pointers, if any */
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xhci_trb_t *cmd_ring; /* Command Ring, XHCI_RING_TRB_COUNT TRBs;
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* index XHCI_RING_TRB_COUNT-1 is a
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* permanent Link TRB back to index 0 */
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uint32_t cmd_ring_cycle; /* current Command Ring Cycle State (RCS) */
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uint32_t cmd_ring_enq; /* next free Command Ring index (0..COUNT-2) */
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xhci_trb_t *evt_ring; /* Event Ring, XHCI_RING_TRB_COUNT TRBs */
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void *evt_ring_seg_table; /* Event Ring Segment Table (1 entry) */
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uint32_t evt_ring_cycle; /* current Event Ring Cycle State */
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uint32_t evt_ring_deq; /* current Event Ring dequeue index */
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xhci_intr_regs_t *intr0; /* Interrupter 0 register set, cached
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* by xhci_bringup() for
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* xhci_poll_events() */
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/* Milestone 2e: connect -> Enable Slot correlation. port_slot_id is
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* indexed by port_id - 1 (1-based port IDs, matching PORTSC/Port
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* Status Change Event numbering); 0 means no slot allocated for that
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* port yet. Fixed-size, not heap-allocated -- XHCI_MAX_TRACKED_PORTS
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* comfortably covers any real or emulated root hub's port count
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* without adding a new kmalloc_aligned() call to xhci_bringup(); ports
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* beyond this bound (checked against both this array and max_ports)
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* are simply not tracked, matching this driver's existing preference
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* for fixed allocations over dynamic growth (xhci.h's own ring-sizing
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* rationale). Only one Enable Slot is ever in flight at a time (this
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* driver issues commands synchronously with respect to connect events,
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* not a queue) -- pending_connect_port_id is 0 when idle, or the
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* port_id whose Command Completion Event is still outstanding. */
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uint32_t port_slot_id[XHCI_MAX_TRACKED_PORTS];
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uint32_t pending_connect_port_id;
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} xhci_dev_t;
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/*
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* xhci_find_and_map — locate the xHCI controller on PCI bus 0, enable it
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* (I/O+MEM+bus-master), map its BAR0 MMIO region, and
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* fill in the four register-region pointers in *dev.
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*
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* dev must point to a zero-initialised xhci_dev_t.
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*
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* Returns 0 on success.
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* Returns -1 if no xHCI device was found on the PCI bus.
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* Returns -2 if the BAR0 mapping failed.
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*/
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int xhci_find_and_map(xhci_dev_t *dev);
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/*
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* xhci_bringup — reset the controller, allocate and program the DCBAA,
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* Command Ring, and Event Ring (Interrupter 0), then start
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* the controller (RUN/STOP=1) and confirm it left the
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* halted state.
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*
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* Must be called after a successful xhci_find_and_map(). Does not enable
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* interrupts (USBCMD.INTE / IMAN.IE) -- this driver is polled, not
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* interrupt-driven (see xhci_poll_events()'s own doc comment for why).
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*
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* Returns 0 on success.
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* Returns -1 on reset timeout.
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* Returns -2 on allocation failure.
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* Returns -3 if the controller failed to leave the halted state after RUN.
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* On success, latches dev into the module-static pointer xhci_poll_events()
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* reads -- only one controller is supported, matching virtio_blk's
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* single-device precedent.
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*/
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int xhci_bringup(xhci_dev_t *dev);
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/*
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* xhci_poll_events — read Interrupter 0's Event Ring, dispatching each TRB
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* by type: Port Status Change reads PORTSC to log
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* connect/disconnect and acknowledges CSC; Command
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* Completion and Transfer Event are logged only (slot
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* allocation and BOT transfers are later increments).
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* Advances the Event Ring dequeue pointer and clears
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* ERDP.EHB when done.
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*
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* Polled, not interrupt-driven: an initial attempt at IRQ delivery
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* (Milestone 2d's first draft) found the amd64 PCI INTx routing formula
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* gives a demonstrably wrong GSI (checked live via QMP query-pci: xHCI at
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* PCI slot 4 reports IRQ 10, the formula predicted 16), and the
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* aarch64/riscv64 slot/pin-derived source IDs were unverified at the new
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* slot this controller occupies. Rather than guess further at chipset
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* PIRQ routing, this matches Section U item 6's own design intent
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* (Captain Bob: "interrupt-driven, coarse cadence, cheap early-exit...
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* quick check blocks... done") via sk_repl_idle()'s existing coarse-cadence
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* hook instead of a per-arch IRQ path -- USB insertion is a human-timescale
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* event, not a hot path, so polling costs nothing meaningful here.
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*
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* No arguments and no return value -- only one xHCI controller is
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* supported, so the caller needs no device handle. A no-op if
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* xhci_bringup() has not completed successfully (dev pointer not yet
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* latched).
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*/
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void xhci_poll_events(void);
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/*
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* xhci_cmd_enable_slot — submit an Enable Slot command TRB to the Command
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* Ring and ring doorbell 0. Does not wait for or
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* read the resulting Command Completion Event -- it
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* arrives asynchronously via xhci_poll_events(),
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* which correlates the returned Slot ID back to
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* dev->pending_connect_port_id and records it in
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* dev->port_slot_id[].
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*
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* Called from xhci_poll_events()'s own Port Status Change handling on a
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* real connect event -- not called directly by other code.
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*
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* Returns 0 if the command was posted, -1 if dev/dev->cmd_ring is not set
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* up (xhci_bringup() has not completed).
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*/
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int xhci_cmd_enable_slot(xhci_dev_t *dev);
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#endif /* STARKERNEL_XHCI_DRIVER_H */
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