drivers/usbstor: one poll thread for the driver, poll card readers only

- one thread walks a list of devices instead of a thread per device
- poll multi-LUN devices and units empty at attach; plain sticks are skipped
- treat UNIT ATTENTION 06/3A as medium removed

Assisted-by: Claude Opus 5 <noreply@anthropic.com>

drivers/usb/usbstor.asm

@@ -167,6 +167,8 @@ LogicalDevices          dd      ?       ; pointer to array of usb_unit_data
 ; 1 for a connected USB device, 1 for each disk device
 ; the structure can be freed when .NumReferences decreases to zero
 NumReferences           dd      ?       ; number of references
+PollNext                dd      ?
+PollPrev                dd      ?
 ConfigRequest           rb      8       ; buffer for configuration requests
 LengthRest              dd      ?       ; Length - (size of data which were transferred)
 ; All requests to a given device are serialized,
@@ -193,7 +195,7 @@ Parent          dd      ?       ; pointer to parent usb_device_data
 LUN             db      ?       ; index in usb_device_data.LogicalDevices array
 DiskIndex       db      ?       ; for name "usbhd<index>"
 MediaPresent    db      ?
-                db      ?       ; alignment
+Polled          db      ?
 DiskDevice      dd      ?       ; handle of disk device or NULL
 SectorSize      dd      ?       ; sector size
 ; For some devices, the first request to the medium fails with 'unit not ready'.
@@ -248,6 +250,20 @@ end virtual
 ; The name is my_driver = 'usbstor'; IOCTL interface is not supported;
 ; usb_functions is an offset of a structure with callback functions.
         invoke  RegUSBDriver, my_driver, 0, usb_functions
+        test    eax, eax
+        jz      .nothing
+        push    eax ebx
+        mov     ecx, poll_lock
+        invoke  MutexInit
+        mov     [poll_head], poll_list
+        mov     [poll_head+4], poll_list
+        movi    ebx, 1
+        mov     ecx, poll_thread
+        xor     edx, edx
+        invoke  CreateThread
+        cmp     eax, -1
+        setnz   [poll_running]
+        pop     ebx eax
 ; 4. Return the returned value of RegUSBDriver.
 .nothing:
         ret
@@ -324,6 +340,9 @@ endp
 proc complete_request
 ; 1. Print common debug messages on fails.
 if DEBUG
+        mov     ebx, [esi+usb_device_data.RequestsQueue+request_queue_item.Next]
+        cmp     [ebx+request_queue_item.Callback], poll_tur_callback
+        jz      .normal
         cmp     [esi+usb_device_data.Status.Status], CSW_STATUS_FAIL
         jb      .normal
         jz      .fail
@@ -1293,6 +1312,7 @@ end virtual
         mov     [esi+usb_unit_data.LUN], cl
         xor     eax, eax
         mov     [esi+usb_unit_data.MediaPresent], al
+        mov     [esi+usb_unit_data.Polled], al
         mov     [esi+usb_unit_data.DiskDevice], eax
         mov     [esi+usb_unit_data.SectorSize], eax
         mov     [esi+usb_unit_data.UnitReadyAttempts], eax
@@ -1305,6 +1325,19 @@ end virtual
         add     esi, sizeof.usb_unit_data
         cmp     ecx, [ebx+usb_device_data.MaxLUN]
         jbe     .looplun
+        cmp     [poll_running], 0
+        jz      @f
+        lock inc [ebx+usb_device_data.NumReferences]
+        mov     ecx, poll_lock
+        invoke  MutexLock
+        mov     eax, [poll_head+4]
+        mov     [ebx+usb_device_data.PollNext], poll_list
+        mov     [ebx+usb_device_data.PollPrev], eax
+        mov     [eax+usb_device_data.PollNext], ebx
+        mov     [poll_head+4], ebx
+        mov     ecx, poll_lock
+        invoke  MutexUnlock
+@@:
 ; 4. Return.
         pop     esi ebx
         ret     20
@@ -1338,11 +1371,14 @@ proc inquiry_callback
         test    al, al
         jnz     .nothing
         DEBUGF 1,'K : direct-access mass storage device detected\n'
-; Units that report 'medium not present' (the empty card slot of an LTE
-; modem or card reader) are not registered: the kernel has no media
-; change detection, so such a disk would only sit dead in the file
-; managers. Replugging the device after inserting a card registers it.
         mov     edx, [esp+8]
+        cmp     [ecx+usb_device_data.MaxLUN], 0
+        jnz     .poll
+        cmp     [edx+usb_unit_data.MediaPresent], 0
+        jnz     @f
+.poll:
+        mov     [edx+usb_unit_data.Polled], 1
+@@:
         cmp     [edx+usb_unit_data.MediaPresent], 0
         jnz     @f
         DEBUGF 1,'K : no media, not registering the disk\n'
@@ -1435,15 +1471,16 @@ end virtual
 endp
 
 ; Temporary thread for initial actions with a new disk device.
-proc new_disk_thread
+new_disk_thread:
+        stdcall add_disk, [esp]
+        or      eax, -1
+        int     0x40
+
+proc add_disk
+        push    ebx esi edi
+        mov     esi, [esp+16]
         sub     esp, 32
-virtual at esp
-.name   rb      32      ; device name
-.param  dd      ?       ; contents of edx at the moment of int 0x40/eax=51
-        dd      ?       ; stack segment
-end virtual
 ; We are ready to notify the kernel about a new disk device.
-        mov     esi, [.param]
 ; 1. Generate name.
 ; 1a. Find a free index.
         mov     ecx, free_numbers_lock
@@ -1512,7 +1549,7 @@ end virtual
         jmp     .exit
 .disconnected:
         invoke  MutexUnlock
-        stdcall disk_close, ebx
+        invoke  DiskDel, ebx
         jmp     .exit
 .free_index:
         mov     ecx, free_numbers_lock
@@ -1521,6 +1558,7 @@ end virtual
         bts     [free_numbers], eax
         invoke  MutexUnlock
 .drop_reference:
+        mov     [esi+usb_unit_data.MediaPresent], 0
         mov     esi, [esi+usb_unit_data.Parent]
         lock dec [esi+usb_device_data.NumReferences]
         jnz     .exit
@@ -1529,8 +1567,186 @@ end virtual
         xchg    eax, esi
         invoke  Kfree
 .exit:
-        or      eax, -1
+        add     esp, 32
+        pop     edi esi ebx
+        ret     4
+endp
+
+; Every POLL_INTERVAL, check removable units for inserted or removed media.
+POLL_INTERVAL = 200
+
+POLL_READY      = 0
+POLL_NO_MEDIA   = 1
+POLL_CHANGED    = 2
+POLL_OTHER      = 3
+
+proc poll_thread
+.loop:
+        movi    eax, 5
+        mov     ebx, POLL_INTERVAL
         int     0x40
+        mov     ecx, poll_lock
+        invoke  MutexLock
+        mov     ebx, [poll_head]
+.device:
+        cmp     ebx, poll_list
+        jz      .done
+        mov     ecx, poll_lock
+        invoke  MutexUnlock
+        cmp     [ebx+usb_device_data.DeviceDisconnected], 0
+        jnz     .remove
+        mov     esi, [ebx+usb_device_data.LogicalDevices]
+        mov     edi, [ebx+usb_device_data.MaxLUN]
+        inc     edi
+.unit:
+        cmp     [esi+usb_unit_data.Polled], 0
+        jz      .next
+        call    poll_unit
+.next:
+        add     esi, sizeof.usb_unit_data
+        dec     edi
+        jnz     .unit
+        mov     ecx, poll_lock
+        invoke  MutexLock
+        mov     ebx, [ebx+usb_device_data.PollNext]
+        jmp     .device
+.remove:
+        mov     ecx, poll_lock
+        invoke  MutexLock
+        mov     eax, [ebx+usb_device_data.PollNext]
+        mov     edx, [ebx+usb_device_data.PollPrev]
+        mov     [edx+usb_device_data.PollNext], eax
+        mov     [eax+usb_device_data.PollPrev], edx
+        push    eax
+        lock dec [ebx+usb_device_data.NumReferences]
+        jnz     @f
+        mov     eax, [ebx+usb_device_data.LogicalDevices]
+        invoke  Kfree
+        xchg    eax, ebx
+        invoke  Kfree
+@@:
+        pop     ebx
+        jmp     .device
+.done:
+        mov     ecx, poll_lock
+        invoke  MutexUnlock
+        jmp     .loop
+endp
+
+proc poll_unit
+        push    edi
+        stdcall poll_tur, ebx, esi
+        cmp     [esi+usb_unit_data.MediaPresent], 0
+        jnz     .registered
+        cmp     eax, POLL_CHANGED
+        jnz     @f
+        stdcall poll_tur, ebx, esi
+@@:
+        cmp     eax, POLL_READY
+        jnz     .done
+        movzx   eax, [esi+usb_unit_data.LUN]
+        DEBUGF 1,'K : medium inserted, LUN %d\n',eax
+        mov     [esi+usb_unit_data.MediaPresent], 1
+        lock inc [ebx+usb_device_data.NumReferences]
+        stdcall add_disk, esi
+        jmp     .done
+.registered:
+        cmp     eax, POLL_NO_MEDIA
+        jz      .removed
+        cmp     eax, POLL_CHANGED
+        jnz     .done
+.removed:
+        lea     ecx, [ebx+usb_device_data.QueueLock]
+        invoke  MutexLock
+        xor     edi, edi
+        cmp     [ebx+usb_device_data.DeviceDisconnected], 0
+        jnz     @f
+        xchg    edi, [esi+usb_unit_data.DiskDevice]
+@@:
+        lea     ecx, [ebx+usb_device_data.QueueLock]
+        invoke  MutexUnlock
+        test    edi, edi
+        jz      .done
+        movzx   eax, [esi+usb_unit_data.LUN]
+        DEBUGF 1,'K : medium removed, LUN %d\n',eax
+        invoke  DiskDel, edi
+.done:
+        pop     edi
+        ret
+endp
+
+proc poll_tur stdcall uses ebx esi edi, device:dword, unit:dword
+        xor     esi, esi
+        xor     ecx, ecx
+        invoke  CreateEvent
+        test    eax, eax
+        jz      .fail
+        push    eax
+        push    edx
+        push    POLL_OTHER
+        push    [unit]
+        mov     edx, esp
+        stdcall queue_request, [device], poll_tur_req, 0, poll_tur_callback, edx
+        mov     eax, [esp+12]
+        mov     ebx, [esp+8]
+        invoke  WaitEvent
+        mov     eax, [esp+4]
+        add     esp, 16
+        ret
+.fail:
+        movi    eax, POLL_OTHER
+        ret
+endp
+
+proc poll_tur_req
+        mov     eax, [esp+8]
+        mov     eax, [eax]
+        mov     al, [eax+usb_unit_data.LUN]
+        mov     [edx+command_block_wrapper.Length], 0
+        mov     [edx+command_block_wrapper.Flags], CBW_FLAG_IN
+        mov     [edx+command_block_wrapper.LUN], al
+        mov     byte [edx+usb_device_data.Sense.ErrorCode-usb_device_data.Command], 0
+        ret     8
+endp
+
+proc poll_tur_callback
+        mov     ecx, [esp+4]
+        xor     eax, eax
+        mov     dl, [ecx+usb_device_data.Status.Status]
+        cmp     dl, CSW_STATUS_OK
+        jz      .done
+        mov     al, POLL_OTHER
+        cmp     dl, CSW_STATUS_FAIL
+        jnz     .done
+        mov     dl, [ecx+usb_device_data.Sense.ErrorCode]
+        and     dl, 7Eh
+        cmp     dl, 70h
+        jnz     .done
+        mov     dl, [ecx+usb_device_data.Sense.SenseKey]
+        and     dl, 0Fh
+        mov     dh, [ecx+usb_device_data.Sense.AdditionalSenseCode]
+        cmp     dx, (3Ah shl 8) + SENSE_NOT_READY
+        jz      .no_media
+        cmp     dx, (3Ah shl 8) + SENSE_UNIT_ATTENTION
+        jnz     @f
+.no_media:
+        mov     al, POLL_NO_MEDIA
+        jmp     .done
+@@:
+        cmp     dx, (28h shl 8) + SENSE_UNIT_ATTENTION
+        jnz     .done
+        mov     al, POLL_CHANGED
+.done:
+        mov     ecx, [esp+8]
+        mov     [ecx+4], eax
+        push    ebx esi edi
+        mov     eax, [ecx+12]
+        mov     ebx, [ecx+8]
+        xor     edx, edx
+        xor     esi, esi
+        invoke  RaiseEvent
+        pop     edi esi ebx
+        ret     8
 endp
 
 ; This function is called when the device is disconnected.
@@ -1559,16 +1775,15 @@ end virtual
         invoke  MutexLock
         mov     [esi+usb_device_data.DeviceDisconnected], 1
         invoke  MutexUnlock
-; 3. Drop one reference to the structure and check whether
-; that was the last reference.
-        lock dec [esi+usb_device_data.NumReferences]
-        jz      .free
-; 4. If not, there are some additional references due to disk devices;
-; notify the kernel that those disks are deleted.
+; 3. Notify the kernel that all disk devices are deleted.
 ; Note that new disks cannot be added while we are looping here,
 ; because new_disk_thread checks for .DeviceDisconnected.
+        mov     eax, [esi+usb_device_data.LogicalDevices]
+        test    eax, eax
+        jz      .unref
+        push    esi
         mov     ebx, [esi+usb_device_data.MaxLUN]
-        mov     esi, [esi+usb_device_data.LogicalDevices]
+        mov     esi, eax
         inc     ebx
 .diskdel:
         mov     eax, [esi+usb_unit_data.DiskDevice]
@@ -1579,12 +1794,17 @@ end virtual
         add     esi, sizeof.usb_unit_data
         dec     ebx
         jnz     .diskdel
-; In this case, some operations with those disks are still possible,
-; so we can't do anything more now. disk_close will take care of the rest.
+        pop     esi
+.unref:
+; 4. Drop one reference to the structure and check whether
+; that was the last reference. If not, some operations with the disks
+; are still possible; disk_close will take care of the rest.
+        lock dec [esi+usb_device_data.NumReferences]
+        jz      .free
 .return:
         pop     esi ebx
         ret     4
-; 5. If there are no disk devices, free all resources which were allocated.
+; 5. If that was the last reference, free all resources which were allocated.
 .free:
         mov     eax, [esi+usb_device_data.LogicalDevices]
         test    eax, eax
@@ -1617,6 +1837,7 @@ end virtual
         movzx   eax, [esi+usb_unit_data.DiskIndex]
         bts     [free_numbers], eax
         invoke  MutexUnlock
+        mov     [esi+usb_unit_data.MediaPresent], 0
         mov     esi, [esi+usb_unit_data.Parent]
         lock dec [esi+usb_device_data.NumReferences]
         jnz     .nothing
@@ -2066,6 +2287,10 @@ data fixups
 end data
 
 free_numbers_lock       rd      3
+poll_lock               rd      3
+poll_head               rd      2
+poll_list = poll_head - usb_device_data.PollNext
+poll_running            db      ?
 ; 128 devices should be enough for everybody
 free_numbers    dd      -1, -1, -1, -1