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; Initialization of the USB subsystem.

; Provides usb_init procedure, includes all needed files.

; General notes:

; * There is one entry point for external kernel code: usb_init is called

;   from initialization code and initializes USB subsystem.

; * There are several entry points for API; see the docs for description.

; * There are several functions which are called from controller-specific

;   parts of USB subsystem. The most important is usb_new_device,

;   which is called when a new device has been connected (over some time),

;   has been reset and is ready to start configuring.

; * IRQ handlers are very restricted. They can not take any locks,

;   since otherwise a deadlock is possible: imagine that a code has taken the

;   lock and was interrupted by IRQ handler. Now IRQ handler would wait for

;   releasing the lock, and a lock owner would wait for exiting IRQ handler

;   to get the control.

; * Thus, there is the special USB thread which processes almost all activity.

;   IRQ handlers do the minimal processing and wake this thread.

; * Also the USB thread wakes occasionally to process tasks which can be

;   predicted without interrupts. These include e.g. a periodic roothub

;   scanning in UHCI and initializing in USB_CONNECT_DELAY ticks

;   after connecting a new device.

; * The main procedure of USB thread, usb_thread_proc, does all its work

;   by querying usb_hardware_func.ProcessDeferred for every controller

;   and usb_hub_process_deferred for every hub.

;   ProcessDeferred does controller-specific actions and calculates the time

;   when it should be invoked again, possibly infinite.

;   usb_thread_proc selects the minimum from all times returned by

;   ProcessDeferred and sleeps until this moment is reached or the thread

;   is awakened by IRQ handler.

; Initializes the USB subsystem.

proc usb_init

; 1. Initialize all locks.

        mov     ecx, usb_controllers_list_mutex

        call    mutex_init

        mov     ecx, usb1_ep_mutex

        call    mutex_init

        mov     ecx, usb_gtd_mutex

        call    mutex_init

        mov     ecx, ehci_ep_mutex

        call    mutex_init

        mov     ecx, ehci_gtd_mutex

        call    mutex_init

; 2. Kick off BIOS from all USB controllers, calling the corresponding function

; *hci_kickoff_bios. Also count USB controllers for the next step.

; Note: USB1 companion(s) must go before the corresponding EHCI controller,

; otherwise BIOS could see a device moving from EHCI to a companion;

; first, this always wastes time;

; second, some BIOSes are buggy, do not expect that move and try to refer to

; previously-assigned controller instead of actual; sometimes that leads to

; hangoff.

; Thus, process controllers in PCI order.

        mov     esi, pcidev_list

        push    0

.kickoff:

        mov     esi, [esi+PCIDEV.fd]

        cmp     esi, pcidev_list

        jz      .done_kickoff

        cmp     word [esi+PCIDEV.class+1], 0x0C03

        jnz     .kickoff

        mov     eax, uhci_kickoff_bios

        cmp     byte [esi+PCIDEV.class], 0x00

        jz      .do_kickoff

        mov     eax, ohci_kickoff_bios

        cmp     byte [esi+PCIDEV.class], 0x10

        jz      .do_kickoff

        mov     eax, ehci_kickoff_bios

        cmp     byte [esi+PCIDEV.class], 0x20

        jnz     .kickoff

.do_kickoff:

        inc     dword [esp]

        call    eax

        jmp     .kickoff

.done_kickoff:

        pop     eax

; 3. If no controllers were found, exit.

; Otherwise, run the USB thread.

        test    eax, eax

        jz      .nothing

        call    create_usb_thread

        jz      .nothing

; 4. Initialize all USB controllers, calling usb_init_controller for each.

; Note: USB1 companion(s) should go before the corresponding EHCI controller,

; although this is not strictly necessary (this way, a companion would not try

; to initialize high-speed device only to see a disconnect when EHCI takes

; control).

; Thus, process all EHCI controllers in the first loop, all USB1 controllers

; in the second loop. (One loop in reversed PCI order could also be used,

; but seems less natural.)

; 4a. Loop over all PCI devices, call usb_init_controller

; for all EHCI controllers.

        mov     eax, pcidev_list

.scan_ehci:

        mov     eax, [eax+PCIDEV.fd]

        cmp     eax, pcidev_list

        jz      .done_ehci

        cmp     [eax+PCIDEV.class], 0x0C0320

        jnz     .scan_ehci

        mov     edi, ehci_hardware_func

        call    usb_init_controller

        jmp     .scan_ehci

.done_ehci:

; 4b. Loop over all PCI devices, call usb_init_controller

; for all UHCI and OHCI controllers.

        mov     eax, pcidev_list

.scan_usb1:

        mov     eax, [eax+PCIDEV.fd]

        cmp     eax, pcidev_list

        jz      .done_usb1

        mov     edi, uhci_hardware_func

        cmp     [eax+PCIDEV.class], 0x0C0300

        jz      @f

        mov     edi, ohci_hardware_func

        cmp     [eax+PCIDEV.class], 0x0C0310

        jnz     .scan_usb1

@@:

        call    usb_init_controller

        jmp     .scan_usb1

.done_usb1:

.nothing:

        ret

endp

uglobal

align 4

usb_event       dd      ?

endg

; Helper function for usb_init. Creates and initializes the USB thread.

proc create_usb_thread

; 1. Create the thread.

        push    edi

        push    1

        pop     ebx

        mov     ecx, usb_thread_proc

        xor     edx, edx

        call    new_sys_threads

        pop     edi

; If failed, say something to the debug board and return with ZF set.

        test    eax, eax

        jns     @f

        DEBUGF 1,'K : cannot create kernel thread for USB, error %d\n',eax

.clear:

        xor     eax, eax

        jmp     .nothing

@@:

; 2. Wait while the USB thread initializes itself.

@@:

        call    change_task

        cmp     [usb_event], 0

        jz      @b

; 3. If initialization failed, the USB thread sets [usb_event] to -1.

; Return with ZF set or cleared corresponding to the result.

        cmp     [usb_event], -1

        jz      .clear

.nothing:

        ret

endp

; Helper function for IRQ handlers. Wakes the USB thread if ebx is nonzero.

proc usb_wakeup_if_needed

        test    ebx, ebx

        jz      usb_wakeup.nothing

usb_wakeup:

        xor     edx, edx

        mov     eax, [usb_event]

        mov     ebx, [eax+EVENT.id]

        xor     esi, esi

        call    raise_event

.nothing:

        ret

endp

; Main loop of the USB thread.

proc usb_thread_proc

; 1. Initialize: create event to allow wakeup by interrupt handlers.

        xor     esi, esi

        mov     ecx, MANUAL_DESTROY

        call    create_event

        test    eax, eax

        jnz     @f

; If failed, set [usb_event] to -1 and terminate myself.

        dbgstr 'cannot create event for USB thread'

        or      [usb_event], -1

        jmp     sys_end

@@:

        mov     [usb_event], eax

        push    -1              ; initial timeout: infinite

usb_thread_wait:

; 2. Main loop: wait for either wakeup event or timeout.

        pop     ecx             ; get timeout

        mov     eax, [usb_event]

        mov     ebx, [eax+EVENT.id]

        call    wait_event_timeout

        push    -1              ; default timeout: infinite

; 3. Main loop: call worker functions of all controllers;

; if some function schedules wakeup in timeout less than the current value,

; replace that value with the returned timeout.

        mov     esi, usb_controllers_list

@@:

        mov     esi, [esi+usb_controller.Next]

        cmp     esi, usb_controllers_list

        jz      .controllers_done

        mov     eax, [esi+usb_controller.HardwareFunc]

        call    [eax+usb_hardware_func.ProcessDeferred]

        cmp     [esp], eax

        jb      @b

        mov     [esp], eax

        jmp     @b

.controllers_done:

; 4. Main loop: call hub worker function for all hubs,

; similarly calculating minimum of all returned timeouts.

; When done, continue to 2.

        mov     esi, usb_hubs_list

@@:

        mov     esi, [esi+usb_hub.Next]

        cmp     esi, usb_hubs_list

        jz      usb_thread_wait

        call    usb_hub_process_deferred

        cmp     [esp], eax

        jb      @b

        mov     [esp], eax

        jmp     @b

endp

iglobal

align 4

usb_controllers_list:

        dd      usb_controllers_list

        dd      usb_controllers_list

usb_hubs_list:

        dd      usb_hubs_list

        dd      usb_hubs_list

endg

uglobal

align 4

usb_controllers_list_mutex      MUTEX

endg

include "memory.inc"

include "hccommon.inc"

include "pipe.inc"

include "ohci.inc"

include "uhci.inc"

include "ehci.inc"

include "protocol.inc"

include "hub.inc"

include "scheduler.inc"