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  1. ; Implementation of the USB protocol for device enumeration.
  2. ; Manage a USB device when it becomes ready for USB commands:
  3. ; configure, enumerate, load the corresponding driver(s),
  4. ; pass device information to the driver.
  5.  
  6. ; =============================================================================
  7. ; ================================= Constants =================================
  8. ; =============================================================================
  9. ; USB standard request codes
  10. USB_GET_STATUS        = 0
  11. USB_CLEAR_FEATURE     = 1
  12. USB_SET_FEATURE       = 3
  13. USB_SET_ADDRESS       = 5
  14. USB_GET_DESCRIPTOR    = 6
  15. USB_SET_DESCRIPTOR    = 7
  16. USB_GET_CONFIGURATION = 8
  17. USB_SET_CONFIGURATION = 9
  18. USB_GET_INTERFACE     = 10
  19. USB_SET_INTERFACE     = 11
  20. USB_SYNCH_FRAME       = 12
  21.  
  22. ; USB standard descriptor types
  23. USB_DEVICE_DESCR             = 1
  24. USB_CONFIG_DESCR             = 2
  25. USB_STRING_DESCR             = 3
  26. USB_INTERFACE_DESCR          = 4
  27. USB_ENDPOINT_DESCR           = 5
  28. USB_DEVICE_QUALIFIER_DESCR   = 6
  29. USB_OTHER_SPEED_CONFIG_DESCR = 7
  30. USB_INTERFACE_POWER_DESCR    = 8
  31.  
  32. ; Compile-time setting. If set, the code will dump all descriptors as they are
  33. ; read to the debug board.
  34. USB_DUMP_DESCRIPTORS = 1
  35.  
  36. ; According to the USB specification (9.2.6.3),
  37. ; any device must response to SET_ADDRESS in 50 ms, or 5 timer ticks.
  38. ; Of course, our world is far from ideal.
  39. ; I have seen devices that just NAK everything when being reset from working
  40. ; state, but start to work after second reset.
  41. ; Our strategy is as follows: give 2 seconds for the first attempt,
  42. ; this should be enough for normal devices and not too long to detect buggy ones.
  43. ; If the device continues NAKing, reset it and retry several times,
  44. ; doubling the interval: 2s -> 4s -> 8s -> 16s. Give up after that.
  45. ; Numbers are quite arbitrary.
  46. TIMEOUT_SET_ADDRESS_INITIAL = 200
  47. TIMEOUT_SET_ADDRESS_LAST    = 1600
  48.  
  49. ; =============================================================================
  50. ; ================================ Structures =================================
  51. ; =============================================================================
  52. ; USB descriptors. See USB specification for detailed explanations.
  53. ; First two bytes of every descriptor have the same meaning.
  54. struct usb_descr
  55. bLength                 db      ?
  56. ; Size of this descriptor in bytes
  57. bDescriptorType         db      ?
  58. ; One of USB_*_DESCR constants.
  59. ends
  60.  
  61. ; USB device descriptor
  62. struct usb_device_descr usb_descr
  63. bcdUSB                  dw      ?
  64. ; USB Specification Release number in BCD, e.g. 110h = USB 1.1
  65. bDeviceClass            db      ?
  66. ; USB Device Class Code
  67. bDeviceSubClass         db      ?
  68. ; USB Device Subclass Code
  69. bDeviceProtocol         db      ?
  70. ; USB Device Protocol Code
  71. bMaxPacketSize0         db      ?
  72. ; Maximum packet size for zero endpoint
  73. idVendor                dw      ?
  74. ; Vendor ID
  75. idProduct               dw      ?
  76. ; Product ID
  77. bcdDevice               dw      ?
  78. ; Device release number in BCD
  79. iManufacturer           db      ?
  80. ; Index of string descriptor describing manufacturer
  81. iProduct                db      ?
  82. ; Index of string descriptor describing product
  83. iSerialNumber           db      ?
  84. ; Index of string descriptor describing serial number
  85. bNumConfigurations      db      ?
  86. ; Number of possible configurations
  87. ends
  88.  
  89. ; USB configuration descriptor
  90. struct usb_config_descr usb_descr
  91. wTotalLength            dw      ?
  92. ; Total length of data returned for this configuration
  93. bNumInterfaces          db      ?
  94. ; Number of interfaces in this configuration
  95. bConfigurationValue     db      ?
  96. ; Value for SET_CONFIGURATION control request
  97. iConfiguration          db      ?
  98. ; Index of string descriptor describing this configuration
  99. bmAttributes            db      ?
  100. ; Bit 6 is SelfPowered, bit 5 is RemoteWakeupSupported,
  101. ; bit 7 must be 1, other bits must be 0
  102. bMaxPower               db      ?
  103. ; Maximum power consumption from the bus in 2mA units
  104. ends
  105.  
  106. ; USB interface descriptor
  107. struct usb_interface_descr usb_descr
  108. ; The following two fields work in pair. Sometimes one interface can work
  109. ; in different modes; e.g. videostream from web-cameras requires different
  110. ; bandwidth depending on resolution/quality/compression settings.
  111. ; Each mode of each interface has its own descriptor with its own endpoints
  112. ; following; all descriptors for one interface have the same bInterfaceNumber,
  113. ; and different bAlternateSetting.
  114. ; By default, any interface operates in mode with bAlternateSetting = 0.
  115. ; Often this is the only mode. If there are another modes, the active mode
  116. ; is selected by SET_INTERFACE(bAlternateSetting) control request.
  117. bInterfaceNumber        db      ?
  118. bAlternateSetting       db      ?
  119. bNumEndpoints           db      ?
  120. ; Number of endpoints used by this interface, excluding zero endpoint
  121. bInterfaceClass         db      ?
  122. ; USB Interface Class Code
  123. bInterfaceSubClass      db      ?
  124. ; USB Interface Subclass Code
  125. bInterfaceProtocol      db      ?
  126. ; USB Interface Protocol Code
  127. iInterface              db      ?
  128. ; Index of string descriptor describing this interface
  129. ends
  130.  
  131. ; USB endpoint descriptor
  132. struct usb_endpoint_descr usb_descr
  133. bEndpointAddress        db      ?
  134. ; Lower 4 bits form endpoint number,
  135. ; upper bit is 0 for OUT endpoints and 1 for IN endpoints,
  136. ; other bits must be zero
  137. bmAttributes            db      ?
  138. ; Lower 2 bits form transfer type, one of *_PIPE,
  139. ; other bits must be zero for non-isochronous endpoints;
  140. ; refer to the USB specification for meaning in isochronous case
  141. wMaxPacketSize          dw      ?
  142. ; Lower 11 bits form maximum packet size,
  143. ; next two bits specify the number of additional transactions per microframe
  144. ; for high-speed periodic endpoints, other bits must be zero.
  145. bInterval               db      ?
  146. ; Interval for polling endpoint for data transfers.
  147. ; Isochronous and high-speed interrupt endpoints: poll every 2^(bInterval-1)
  148. ; (micro)frames
  149. ; Full/low-speed interrupt endpoints: poll every bInterval frames
  150. ; High-speed bulk/control OUT endpoints: maximum NAK rate
  151. ends
  152.  
  153. ; =============================================================================
  154. ; =================================== Code ====================================
  155. ; =============================================================================
  156.  
  157. ; When a new device is ready to be configured, a controller-specific code
  158. ; calls usb_new_device.
  159. ; The sequence of further actions:
  160. ; * open pipe for the zero endpoint (usb_new_device);
  161. ;   maximum packet size is not known yet, but it must be at least 8 bytes,
  162. ;   so it is safe to send packets with <= 8 bytes
  163. ; * issue SET_ADDRESS control request (usb_new_device)
  164. ; * set the new device address in the pipe (usb_set_address_callback)
  165. ; * notify a controller-specific code that initialization of other ports
  166. ;   can be started (usb_set_address_callback)
  167. ; * issue GET_DESCRIPTOR control request for first 8 bytes of device descriptor
  168. ;   (usb_after_set_address)
  169. ; * first 8 bytes of device descriptor contain the true packet size for zero
  170. ;   endpoint, so set the true packet size (usb_get_descr8_callback)
  171. ; * first 8 bytes of a descriptor contain the full size of this descriptor,
  172. ;   issue GET_DESCRIPTOR control request for the full device descriptor
  173. ;   (usb_after_set_endpoint_size)
  174. ; * issue GET_DESCRIPTOR control request for first 8 bytes of configuration
  175. ;   descriptor (usb_get_descr_callback)
  176. ; * issue GET_DESCRIPTOR control request for full configuration descriptor
  177. ;   (usb_know_length_callback)
  178. ; * issue SET_CONFIGURATION control request (usb_set_config_callback)
  179. ; * parse configuration descriptor, load the corresponding driver(s),
  180. ;   pass the configuration descriptor to the driver and let the driver do
  181. ;   the further work (usb_got_config_callback)
  182.  
  183. ; This function is called from controller-specific part
  184. ; when a new device is ready to be configured.
  185. ; in: ecx -> pseudo-pipe, part of usb_pipe
  186. ; in: esi -> usb_controller
  187. ; in: [esi+usb_controller.ResettingHub] is the pointer to usb_hub for device,
  188. ;     NULL if the device is connected to the root hub
  189. ; in: [esi+usb_controller.ResettingPort] is the port for the device, zero-based
  190. ; in: [esi+usb_controller.ResettingSpeed] is the speed of the device, one of
  191. ;     USB_SPEED_xx.
  192. ; out: eax = 0 <=> failed, the caller should disable the port.
  193. proc usb_new_device
  194.         push    ebx edi         ; save used registers to be stdcall
  195. ; 1. Check whether we're here because we were trying to reset
  196. ; already-registered device in hope to fix something serious.
  197. ; If so, skip allocation and go to 6.
  198.         movzx   eax, [esi+usb_controller.ResettingPort]
  199.         mov     edx, [esi+usb_controller.ResettingHub]
  200.         test    edx, edx
  201.         jz      .test_roothub
  202.         mov     edx, [edx+usb_hub.ConnectedDevicesPtr]
  203.         mov     ebx, [edx+eax*4]
  204.         jmp     @f
  205. .test_roothub:
  206.         mov     ebx, [esi+usb_controller.DevicesByPort+eax*4]
  207. @@:
  208.         test    ebx, ebx
  209.         jnz     .try_set_address
  210. ; 2. Allocate resources. Any device uses the following resources:
  211. ; - device address in the bus
  212. ; - memory for device data
  213. ; - pipe for zero endpoint
  214. ; If some allocation fails, we must undo our actions. Closing the pipe
  215. ; is a hard task, so we avoid it and open the pipe as the last resource.
  216. ; The order for other two allocations is quite arbitrary.
  217. ; 2a. Allocate a bus address.
  218.         push    ecx
  219.         call    usb_set_address_request
  220.         pop     ecx
  221. ; 2b. If failed, just return zero.
  222.         test    eax, eax
  223.         jz      .nothing
  224. ; 2c. Allocate memory for device data.
  225. ; For now, we need sizeof.usb_device_data and extra 8 bytes for GET_DESCRIPTOR
  226. ; input and output, see usb_after_set_address. Later we will reallocate it
  227. ; to actual size needed for descriptors.
  228.         movi    eax, sizeof.usb_device_data + 8
  229.         push    ecx
  230.         call    malloc
  231.         pop     ecx
  232. ; 2d. If failed, free the bus address and return zero.
  233.         test    eax, eax
  234.         jz      .nomemory
  235. ; 2e. Open pipe for endpoint zero.
  236. ; For now, we do not know the actual maximum packet size;
  237. ; for full-speed devices it can be any of 8, 16, 32, 64 bytes,
  238. ; low-speed devices must have 8 bytes, high-speed devices must have 64 bytes.
  239. ; Thus, we must use some fake "maximum packet size" until the actual size
  240. ; will be known. However, the maximum packet size must be at least 8, and
  241. ; initial stages of the configuration process involves only packets of <= 8
  242. ; bytes, they will be transferred correctly as long as
  243. ; the fake "maximum packet size" is also at least 8.
  244. ; Thus, any number >= 8 is suitable for actual hardware.
  245. ; However, software emulation of EHCI in VirtualBox assumes that high-speed
  246. ; control transfers are those originating from pipes with max packet size = 64,
  247. ; even on early stages of the configuration process. This is incorrect,
  248. ; but we have no specific preferences, so let VirtualBox be happy and use 64
  249. ; as the fake "maximum packet size".
  250.         push    eax
  251. ; We will need many zeroes.
  252. ; "push edi" is one byte, "push 0" is two bytes; save space, use edi.
  253.         xor     edi, edi
  254.         stdcall usb_open_pipe, ecx, edi, 64, edi, edi
  255. ; Put pointer to pipe into ebx. "xchg eax,reg" is one byte, mov is two bytes.
  256.         xchg    eax, ebx
  257.         pop     eax
  258. ; 2f. If failed, free the memory, the bus address and return zero.
  259.         test    ebx, ebx
  260.         jz      .freememory
  261. ; 3. Store pointer to device data in the pipe structure.
  262.         mov     [ebx+usb_pipe.DeviceData], eax
  263. ; 4. Init device data, using usb_controller.Resetting* variables.
  264.         mov     [eax+usb_device_data.Timer], edi
  265.         mov     dword [eax+usb_device_data.DeviceDescriptor], TIMEOUT_SET_ADDRESS_INITIAL
  266.         mov     [eax+usb_device_data.TTHub], edi
  267.         mov     [eax+usb_device_data.TTPort], 0
  268.         mov     [eax+usb_device_data.NumInterfaces], edi
  269.         mov     [eax+usb_device_data.DeviceDescrSize], 0
  270.         mov     dl, [esi+usb_controller.ResettingSpeed]
  271.         mov     [eax+usb_device_data.Speed], dl
  272.         mov     [eax+usb_device_data.NumPipes], 1
  273.         push    ebx
  274.         cmp     dl, USB_SPEED_HS
  275.         jz      .nott
  276.         mov     ebx, [esi+usb_controller.ResettingHub]
  277.         test    ebx, ebx
  278.         jz      .nott
  279.         mov     cl, [esi+usb_controller.ResettingPort]
  280.         mov     edx, [ebx+usb_hub.ConfigPipe]
  281.         mov     edx, [edx+usb_pipe.DeviceData]
  282.         cmp     [edx+usb_device_data.TTHub], 0
  283.         jz      @f
  284.         mov     cl, [edx+usb_device_data.TTPort]
  285.         mov     ebx, [edx+usb_device_data.TTHub]
  286.         jmp     .has_tt
  287. @@:
  288.         cmp     [edx+usb_device_data.Speed], USB_SPEED_HS
  289.         jnz     .nott
  290. .has_tt:
  291.         mov     [eax+usb_device_data.TTHub], ebx
  292.         mov     [eax+usb_device_data.TTPort], cl
  293. .nott:
  294.         pop     ebx
  295.         mov     [eax+usb_device_data.ConfigDataSize], edi
  296.         mov     [eax+usb_device_data.Interfaces], edi
  297.         movzx   ecx, [esi+usb_controller.ResettingPort]
  298.         mov     [eax+usb_device_data.Port], cl
  299.         mov     edx, [esi+usb_controller.ResettingHub]
  300.         mov     [eax+usb_device_data.Hub], edx
  301. ; 5. Store pointer to the config pipe in the hub data.
  302. ; Config pipe serves as device identifier.
  303. ; Root hubs use the array inside usb_controller structure,
  304. ; non-root hubs use the array immediately after usb_hub structure.
  305.         test    edx, edx
  306.         jz      .roothub
  307.         mov     edx, [edx+usb_hub.ConnectedDevicesPtr]
  308.         mov     [edx+ecx*4], ebx
  309.         jmp     @f
  310. .roothub:
  311.         mov     [esi+usb_controller.DevicesByPort+ecx*4], ebx
  312. @@:
  313.         call    usb_reinit_pipe_list
  314. ; 6. Issue SET_ADDRESS control request, using buffer filled in step 2a.
  315. ; 6a. Configure timer to force reset after timeout.
  316. ; Note: we can't use self-destructing timer, because we need to be able to cancel it,
  317. ; and for self-destructing timer we could have race condition in cancelling/destructing.
  318. ;        DEBUGF 1,'K : pipe %x\n',ebx
  319. .try_set_address:
  320.         xor     edi, edi
  321.         mov     edx, [ebx+usb_pipe.DeviceData]
  322.         stdcall timer_hs, [edx+usb_device_data.DeviceDescriptor], 7FFFFFFFh, usb_abort_pipe, ebx
  323.         test    eax, eax
  324.         jz      .nothing
  325.         mov     edx, [ebx+usb_pipe.DeviceData]
  326.         mov     [edx+usb_device_data.Timer], eax
  327. ; 6b. If it succeeded, setup timer to configure wait timeout.
  328.         lea     eax, [esi+usb_controller.SetAddressBuffer]
  329.         stdcall usb_control_async, ebx, eax, edi, edi, usb_set_address_callback, edi, edi
  330. ; Use the return value from usb_control_async as our return value;
  331. ; if it is zero, then something has failed.
  332. .nothing:
  333. ; 7. Return.
  334.         pop     edi ebx         ; restore used registers to be stdcall
  335.         ret
  336. ; Handlers of failures in steps 2b, 2d, 2f.
  337. .freememory:
  338.         call    free
  339.         jmp     .freeaddr
  340. .nomemory:
  341.         dbgstr 'No memory for device data'
  342. .freeaddr:
  343.         mov     ecx, dword [esi+usb_controller.SetAddressBuffer+2]
  344.         bts     [esi+usb_controller.ExistingAddresses], ecx
  345.         xor     eax, eax
  346.         jmp     .nothing
  347. endp
  348.  
  349. ; Helper procedure for usb_new_device.
  350. ; Allocates a new USB address and fills usb_controller.SetAddressBuffer
  351. ; with data for SET_ADDRESS(allocated_address) request.
  352. ; out: eax = 0 <=> failed
  353. ; Destroys edi.
  354. proc usb_set_address_request
  355. ; There are 128 bits, one for each possible address.
  356. ; Note: only the USB thread works with usb_controller.ExistingAddresses,
  357. ; so there is no need for synchronization.
  358. ; We must find a bit set to 1 and clear it.
  359. ; 1. Find the first dword which has a nonzero bit = which is nonzero.
  360.         mov     ecx, 128/32
  361.         lea     edi, [esi+usb_controller.ExistingAddresses]
  362.         xor     eax, eax
  363.         repz scasd
  364. ; 2. If all dwords are zero, return an error.
  365.         jz      .error
  366. ; 3. The dword at [edi-4] is nonzero. Find the lowest nonzero bit.
  367.         bsf     eax, [edi-4]
  368. ; Now eax = bit number inside the dword at [edi-4].
  369. ; 4. Clear the bit.
  370.         btr     [edi-4], eax
  371. ; 5. Generate the address by edi = memory address and eax = bit inside dword.
  372. ; Address = eax + 8 * (edi-4 - (esi+usb_controller.ExistingAddress)).
  373.         sub     edi, esi
  374.         lea     edi, [eax+(edi-4-usb_controller.ExistingAddresses)*8]
  375. ; 6. Store the allocated address in SetAddressBuffer and fill remaining fields.
  376. ; Note that usb_controller is zeroed at allocation, so only command byte needs
  377. ; to be filled.
  378.         mov     byte [esi+usb_controller.SetAddressBuffer+1], USB_SET_ADDRESS
  379.         mov     dword [esi+usb_controller.SetAddressBuffer+2], edi
  380. ; 7. Return non-zero value in eax.
  381.         inc     eax
  382. .nothing:
  383.         ret
  384. .error:
  385.         dbgstr 'cannot allocate USB address'
  386.         xor     eax, eax
  387.         jmp     .nothing
  388. endp
  389.  
  390. ; This procedure is called by USB stack when SET_ADDRESS request initiated by
  391. ; usb_new_device is completed, either successfully or unsuccessfully.
  392. ; Note that USB stack uses esi = pointer to usb_controller.
  393. proc usb_set_address_callback stdcall, pipe:dword, status:dword, buffer:dword, length:dword, calldata:dword
  394.         push    ebx     ; save ebx to be stdcall
  395.         mov     ebx, [pipe]
  396. ; 1. In any case, cancel the timer.
  397.         mov     eax, [ebx+usb_pipe.DeviceData]
  398.         stdcall cancel_timer_hs, [eax+usb_device_data.Timer]
  399.         mov     eax, [ebx+usb_pipe.DeviceData]
  400.         mov     [eax+usb_device_data.Timer], 0
  401. ; Load data to registers for further references.
  402.         mov     ecx, dword [esi+usb_controller.SetAddressBuffer+2]
  403.         mov     eax, [esi+usb_controller.HardwareFunc]
  404. ; 2. Check whether the device has accepted new address. If so, proceed to 3.
  405. ; Otherwise, go to 4 if killed by usb_set_address_timeout or to 5 otherwise.
  406.         cmp     [status], USB_STATUS_CANCELLED
  407.         jz      .timeout
  408.         cmp     [status], 0
  409.         jnz     .error
  410. ; 3. Address accepted.
  411. ; 3a. The controller-specific structure for the control pipe still uses
  412. ; zero address. Call the controller-specific function to change it to
  413. ; the actual address.
  414. ; Note that the hardware could cache the controller-specific structure,
  415. ; so setting the address could take some time until the cache is evicted.
  416. ; Thus, the call is asynchronous; meet us in usb_after_set_address when it will
  417. ; be safe to continue.
  418. ;        dbgstr 'address set in device'
  419.         call    [eax+usb_hardware_func.SetDeviceAddress]
  420. ; 3b. If the port is in non-root hub, clear 'reset in progress' flag.
  421. ; In any case, proceed to 6.
  422.         mov     eax, [esi+usb_controller.ResettingHub]
  423.         test    eax, eax
  424.         jz      .return
  425.         and     [eax+usb_hub.Actions], not HUB_RESET_IN_PROGRESS
  426. .return:
  427. ; 6. Address configuration done, we can proceed with other ports.
  428. ; Call the worker function for that.
  429.         call    usb_test_pending_port
  430. .wakeup:
  431.         push    esi edi
  432.         call    usb_wakeup
  433.         pop     edi esi
  434. .nothing:
  435.         pop     ebx     ; restore ebx to be stdcall
  436.         ret
  437. .timeout:
  438. ; 4. Device continues to NAK the request. Reset it and retry.
  439.         mov     edx, [ebx+usb_pipe.DeviceData]
  440.         mov     ecx, [edx+usb_device_data.DeviceDescriptor]
  441.         add     ecx, ecx
  442.         cmp     ecx, TIMEOUT_SET_ADDRESS_LAST
  443.         ja      .error
  444.         mov     [edx+usb_device_data.DeviceDescriptor], ecx
  445.         dbgstr 'Timeout in USB device initialization, trying to reset...'
  446.         cmp     [esi+usb_controller.ResettingHub], 0
  447.         jz      .reset_roothub
  448.         push    esi
  449.         mov     esi, [esi+usb_controller.ResettingHub]
  450.         call    usb_hub_initiate_reset
  451.         pop     esi
  452.         jmp     .nothing
  453. .reset_roothub:
  454.         movzx   ecx, [esi+usb_controller.ResettingPort]
  455.         call    [eax+usb_hardware_func.InitiateReset]
  456.         jmp     .wakeup
  457. .error:
  458. ; 5. Device error: device not responding, disconnect etc.
  459.         DEBUGF 1,'K : error %d in SET_ADDRESS, USB device disabled\n',[status]
  460. ; 5a. The address has not been accepted. Mark it as free.
  461.         bts     dword [esi+usb_controller.ExistingAddresses], ecx
  462. ; 5b. Disable the port with bad device.
  463. ; For the root hub, call the controller-specific function and go to 6.
  464. ; For non-root hubs, let the hub code do its work and return (the request
  465. ; could take some time, the hub code is responsible for proceeding).
  466.         cmp     [esi+usb_controller.ResettingHub], 0
  467.         jz      .roothub
  468.         mov     eax, [esi+usb_controller.ResettingHub]
  469.         call    usb_hub_disable_resetting_port
  470.         jmp     .nothing
  471. .roothub:
  472.         movzx   ecx, [esi+usb_controller.ResettingPort]
  473.         call    [eax+usb_hardware_func.PortDisable]
  474.         jmp     .return
  475. endp
  476.  
  477. ; This procedure is called from usb_subscription_done when the hardware cache
  478. ; is cleared after request from usb_set_address_callback.
  479. ; in: ebx -> usb_pipe
  480. proc usb_after_set_address
  481. ;        dbgstr 'address set for controller'
  482. ; Issue control transfer GET_DESCRIPTOR(DEVICE_DESCR) for first 8 bytes.
  483. ; Remember, we still do not know the actual packet size;
  484. ; 8-bytes-request is safe.
  485. ; usb_new_device has allocated 8 extra bytes besides sizeof.usb_device_data;
  486. ; use them for both input and output.
  487.         mov     eax, [ebx+usb_pipe.DeviceData]
  488.         add     eax, usb_device_data.DeviceDescriptor
  489.         mov     dword [eax], \
  490.                 80h + \         ; device-to-host, standard, device-wide
  491.                 (USB_GET_DESCRIPTOR shl 8) + \  ; request
  492.                 (0 shl 16) + \  ; descriptor index: there is only one
  493.                 (USB_DEVICE_DESCR shl 24)       ; descriptor type
  494.         mov     dword [eax+4], 8 shl 16         ; data length
  495.         stdcall usb_control_async, ebx, eax, eax, 8, usb_get_descr8_callback, eax, 0
  496.         ret
  497. endp
  498.  
  499. ; This procedure is called by USB stack when GET_DESCRIPTOR(DEVICE_DESCR)
  500. ; request initiated by usb_after_set_address is completed, either successfully
  501. ; or unsuccessfully.
  502. ; Note that USB stack uses esi = pointer to usb_controller.
  503. proc usb_get_descr8_callback stdcall, pipe:dword, status:dword, buffer:dword, length:dword, calldata:dword
  504. ;       mov     eax, [buffer]
  505. ;       DEBUGF 1,'K : descr8: l=%x; %x %x %x %x %x %x %x %x\n',[length],\
  506. ;               [eax]:2,[eax+1]:2,[eax+2]:2,[eax+3]:2,[eax+4]:2,[eax+5]:2,[eax+6]:2,[eax+7]:2
  507.         push    edi ebx         ; save used registers to be stdcall
  508.         mov     ebx, [pipe]
  509. ; 1. Check whether the operation was successful.
  510. ; If not, say something to the debug board and stop the initialization.
  511.         cmp     [status], 0
  512.         jnz     .error
  513. ; 2. Length of descriptor must be at least sizeof.usb_device_descr bytes.
  514. ; If not, say something to the debug board and stop the initialization.
  515.         mov     eax, [ebx+usb_pipe.DeviceData]
  516.         cmp     [eax+usb_device_data.DeviceDescriptor+usb_device_descr.bLength], sizeof.usb_device_descr
  517.         jb      .error
  518. ; 3. Now first 8 bytes of device descriptor are known;
  519. ; set DeviceDescrSize accordingly.
  520.         mov     [eax+usb_device_data.DeviceDescrSize], 8
  521. ; 4. The controller-specific structure for the control pipe still uses
  522. ; the fake "maximum packet size". Call the controller-specific function to
  523. ; change it to the actual packet size from the device.
  524. ; Note that the hardware could cache the controller-specific structure,
  525. ; so changing it could take some time until the cache is evicted.
  526. ; Thus, the call is asynchronous; meet us in usb_after_set_endpoint_size
  527. ; when it will be safe to continue.
  528.         movzx   ecx, [eax+usb_device_data.DeviceDescriptor+usb_device_descr.bMaxPacketSize0]
  529.         mov     eax, [esi+usb_controller.HardwareFunc]
  530.         call    [eax+usb_hardware_func.SetEndpointPacketSize]
  531. .nothing:
  532. ; 5. Return.
  533.         pop     ebx edi         ; restore used registers to be stdcall
  534.         ret
  535. .error:
  536.         dbgstr 'error with USB device descriptor'
  537.         jmp     .nothing
  538. endp
  539.  
  540. ; This procedure is called from usb_subscription_done when the hardware cache
  541. ; is cleared after request from usb_get_descr8_callback.
  542. ; in: ebx -> usb_pipe
  543. proc usb_after_set_endpoint_size
  544. ; 1. Reallocate memory for device data:
  545. ; add memory for now-known size of device descriptor and extra 8 bytes
  546. ; for further actions.
  547. ; 1a. Allocate new memory.
  548.         mov     eax, [ebx+usb_pipe.DeviceData]
  549.         movzx   eax, [eax+usb_device_data.DeviceDescriptor+usb_device_descr.bLength]
  550. ; save length for step 2
  551.         push    eax
  552.         add     eax, sizeof.usb_device_data + 8
  553.         call    malloc
  554. ; 1b. If failed, say something to the debug board and stop the initialization.
  555.         test    eax, eax
  556.         jz      .nomemory
  557. ; 1c. Copy data from old memory to new memory and switch the pointer in usb_pipe.
  558.         push    eax
  559.         push    esi edi
  560.         mov     esi, [ebx+usb_pipe.DeviceData]
  561.         mov     [ebx+usb_pipe.DeviceData], eax
  562.         mov     edi, eax
  563.         mov     eax, esi
  564.         mov     ecx, sizeof.usb_device_data / 4
  565.         rep movsd
  566.         pop     edi esi
  567.         call    usb_reinit_pipe_list
  568. ; 1d. Free the old memory.
  569.         call    free
  570.         pop     eax
  571. ; 2. Issue control transfer GET_DESCRIPTOR(DEVICE) for full descriptor.
  572. ; restore length saved in step 1a
  573.         pop     edx
  574.         add     eax, sizeof.usb_device_data
  575.         mov     dword [eax], \
  576.                 80h + \         ; device-to-host, standard, device-wide
  577.                 (USB_GET_DESCRIPTOR shl 8) + \  ; request
  578.                 (0 shl 16) + \  ; descriptor index: there is only one
  579.                 (USB_DEVICE_DESCR shl 24)       ; descriptor type
  580.         and     dword [eax+4], 0
  581.         mov     [eax+6], dl     ; data length
  582.         stdcall usb_control_async, ebx, eax, eax, edx, usb_get_descr_callback, eax, 0
  583. ; 3. Return.
  584.         ret
  585. .nomemory:
  586.         dbgstr 'No memory for device data'
  587.         ret
  588. endp
  589.  
  590. ; This procedure is called by USB stack when GET_DESCRIPTOR(DEVICE)
  591. ; request initiated by usb_after_set_endpoint_size is completed,
  592. ; either successfully or unsuccessfully.
  593. proc usb_get_descr_callback stdcall, pipe:dword, status:dword, buffer:dword, length:dword, calldata:dword
  594. ; Note: the prolog is the same as in usb_get_descr8_callback.
  595.         push    edi ebx         ; save used registers to be stdcall
  596. ; 1. Check whether the operation was successful.
  597. ; If not, say something to the debug board and stop the initialization.
  598.         cmp     [status], 0
  599.         jnz     usb_get_descr8_callback.error
  600. ; The full descriptor is known, dump it if specified by compile-time option.
  601. if USB_DUMP_DESCRIPTORS
  602.         mov     eax, [buffer]
  603.         mov     ecx, [length]
  604.         sub     ecx, 8
  605.         jbe     .skipdebug
  606.         DEBUGF 1,'K : device descriptor:'
  607. @@:
  608.         DEBUGF 1,' %x',[eax]:2
  609.         inc     eax
  610.         dec     ecx
  611.         jnz     @b
  612.         DEBUGF 1,'\n'
  613. .skipdebug:
  614. end if
  615. ; 2. Check that bLength is the same as was in the previous request.
  616. ; If not, say something to the debug board and stop the initialization.
  617. ; It is important, because usb_after_set_endpoint_size has allocated memory
  618. ; according to the old bLength. Note that [length] for control transfers
  619. ; includes 8 bytes of setup packet, so data length = [length] - 8.
  620.         mov     eax, [buffer]
  621.         movzx   ecx, [eax+usb_device_descr.bLength]
  622.         add     ecx, 8
  623.         cmp     [length], ecx
  624.         jnz     usb_get_descr8_callback.error
  625. ; Amuse the user if she is watching the debug board.
  626.         mov     cl, [eax+usb_device_descr.bNumConfigurations]
  627.         DEBUGF 1,'K : found USB device with ID %x:%x, %d configuration(s)\n',\
  628.                 [eax+usb_device_descr.idVendor]:4,\
  629.                 [eax+usb_device_descr.idProduct]:4,\
  630.                 cl
  631. ; 3. If there are no configurations, stop the initialization.
  632.         cmp     [eax+usb_device_descr.bNumConfigurations], 0
  633.         jz      .nothing
  634. ; 4. Copy length of device descriptor to device data structure.
  635.         movzx   edx, [eax+usb_device_descr.bLength]
  636.         mov     [eax+usb_device_data.DeviceDescrSize-usb_device_data.DeviceDescriptor], dl
  637. ; 5. Issue control transfer GET_DESCRIPTOR(CONFIGURATION). We do not know
  638. ; the full length of that descriptor, so start with first 8 bytes, they contain
  639. ; the full length.
  640. ; usb_after_set_endpoint_size has allocated 8 extra bytes after the
  641. ; device descriptor, use them for both input and output.
  642.         add     eax, edx
  643.         mov     dword [eax], \
  644.                 80h + \         ; device-to-host, standard, device-wide
  645.                 (USB_GET_DESCRIPTOR shl 8) + \  ; request
  646.                 (0 shl 16) + \  ; descriptor index: there is only one
  647.                 (USB_CONFIG_DESCR shl 24)       ; descriptor type
  648.         mov     dword [eax+4], 8 shl 16         ; data length
  649.         stdcall usb_control_async, [pipe], eax, eax, 8, usb_know_length_callback, eax, 0
  650. .nothing:
  651. ; 6. Return.
  652.         pop     ebx edi         ; restore used registers to be stdcall
  653.         ret
  654. endp
  655.  
  656. ; This procedure is called by USB stack when GET_DESCRIPTOR(CONFIGURATION)
  657. ; request initiated by usb_get_descr_callback is completed,
  658. ; either successfully or unsuccessfully.
  659. proc usb_know_length_callback stdcall, pipe:dword, status:dword, buffer:dword, length:dword, calldata:dword
  660.         push    ebx             ; save used registers to be stdcall
  661. ; 1. Check whether the operation was successful.
  662. ; If not, say something to the debug board and stop the initialization.
  663.         cmp     [status], 0
  664.         jnz     .error
  665. ; 2. Get the total length of data associated with config descriptor and store
  666. ; it in device data structure. The total length must be at least
  667. ; sizeof.usb_config_descr bytes; if not, say something to the debug board and
  668. ; stop the initialization.
  669.         mov     eax, [buffer]
  670.         mov     edx, [pipe]
  671.         movzx   ecx, [eax+usb_config_descr.wTotalLength]
  672.         mov     eax, [edx+usb_pipe.DeviceData]
  673.         cmp     ecx, sizeof.usb_config_descr
  674.         jb      .error
  675.         mov     [eax+usb_device_data.ConfigDataSize], ecx
  676. ; 3. Reallocate memory for device data:
  677. ; include usb_device_data structure, device descriptor,
  678. ; config descriptor with all associated data, and extra bytes
  679. ; sufficient for 8 bytes control packet and for one usb_interface_data struc.
  680. ; Align extra bytes to dword boundary.
  681. if sizeof.usb_interface_data > 8
  682. .extra_size = sizeof.usb_interface_data
  683. else
  684. .extra_size = 8
  685. end if
  686. ; 3a. Allocate new memory.
  687.         movzx   edx, [eax+usb_device_data.DeviceDescrSize]
  688.         lea     eax, [ecx+edx+sizeof.usb_device_data+.extra_size+3]
  689.         and     eax, not 3
  690.         push    eax
  691.         call    malloc
  692.         pop     edx
  693. ; 3b. If failed, say something to the debug board and stop the initialization.
  694.         test    eax, eax
  695.         jz      .nomemory
  696. ; 3c. Copy data from old memory to new memory and switch the pointer in usb_pipe.
  697.         push    eax
  698.         mov     ebx, [pipe]
  699.         push    esi edi
  700.         mov     esi, [ebx+usb_pipe.DeviceData]
  701.         mov     edi, eax
  702.         mov     [ebx+usb_pipe.DeviceData], eax
  703.         mov     eax, esi
  704.         movzx   ecx, [esi+usb_device_data.DeviceDescrSize]
  705.         sub     edx, .extra_size
  706.         mov     [esi+usb_device_data.Interfaces], edx
  707.         add     ecx, sizeof.usb_device_data + 8
  708.         mov     edx, ecx
  709.         shr     ecx, 2
  710.         and     edx, 3
  711.         rep movsd
  712.         mov     ecx, edx
  713.         rep movsb
  714.         pop     edi esi
  715.         call    usb_reinit_pipe_list
  716. ; 3d. Free old memory.
  717.         call    free
  718.         pop     eax
  719. ; 4. Issue control transfer GET_DESCRIPTOR(DEVICE) for full descriptor.
  720.         movzx   ecx, [eax+usb_device_data.DeviceDescrSize]
  721.         mov     edx, [eax+usb_device_data.ConfigDataSize]
  722.         lea     eax, [eax+ecx+sizeof.usb_device_data]
  723.         mov     dword [eax], \
  724.                 80h + \         ; device-to-host, standard, device-wide
  725.                 (USB_GET_DESCRIPTOR shl 8) + \  ; request
  726.                 (0 shl 16) + \  ; descriptor index: there is only one
  727.                 (USB_CONFIG_DESCR shl 24)       ; descriptor type
  728.         and     dword [eax+4], 0
  729.         mov     word [eax+6], dx        ; data length
  730.         stdcall usb_control_async, [pipe], eax, eax, edx, usb_set_config_callback, eax, 0
  731. .nothing:
  732. ; 5. Return.
  733.         pop     ebx             ; restore used registers to be stdcall
  734.         ret
  735. .error:
  736.         dbgstr 'error with USB configuration descriptor'
  737.         jmp     .nothing
  738. .nomemory:
  739.         dbgstr 'No memory for device data'
  740.         jmp     .nothing
  741. endp
  742.  
  743. ; This procedure is called by USB stack when GET_DESCRIPTOR(CONFIGURATION)
  744. ; request initiated by usb_know_length_callback is completed,
  745. ; either successfully or unsuccessfully.
  746. proc usb_set_config_callback stdcall, pipe:dword, status:dword, buffer:dword, length:dword, calldata:dword
  747. ; Note that the prolog is the same as in usb_know_length_callback.
  748.         push    ebx             ; save used registers to be stdcall
  749. ; 1. Check whether the operation was successful.
  750. ; If not, say something to the debug board and stop the initialization.
  751.         xor     ecx, ecx
  752.         mov     ebx, [pipe]
  753.         cmp     [status], ecx
  754.         jnz     usb_know_length_callback.error
  755. ; The full descriptor is known, dump it if specified by compile-time option.
  756. if USB_DUMP_DESCRIPTORS
  757.         mov     eax, [buffer]
  758.         mov     ecx, [length]
  759.         sub     ecx, 8
  760.         jbe     .skip_debug
  761.         DEBUGF 1,'K : config descriptor:'
  762. @@:
  763.         DEBUGF 1,' %x',[eax]:2
  764.         inc     eax
  765.         dec     ecx
  766.         jnz     @b
  767.         DEBUGF 1,'\n'
  768. .skip_debug:
  769.         xor     ecx, ecx
  770. end if
  771. ; 2. Issue control transfer SET_CONFIGURATION to activate this configuration.
  772. ; Usually this is the only configuration.
  773. ; Use extra bytes allocated by usb_know_length_callback;
  774. ; offset from device data start is stored in Interfaces.
  775.         mov     eax, [ebx+usb_pipe.DeviceData]
  776.         mov     edx, [buffer]
  777.         add     eax, [eax+usb_device_data.Interfaces]
  778.         mov     dl, [edx+usb_config_descr.bConfigurationValue]
  779.         mov     dword [eax], USB_SET_CONFIGURATION shl 8
  780.         mov     dword [eax+4], ecx
  781.         mov     byte [eax+2], dl
  782.         stdcall usb_control_async, [pipe], eax, ecx, ecx, usb_got_config_callback, [buffer], ecx
  783.         pop     ebx             ; restore used registers to be stdcall
  784.         ret
  785. endp
  786.  
  787. ; This procedure is called by USB stack when SET_CONFIGURATION
  788. ; request initiated by usb_set_config_callback is completed,
  789. ; either successfully or unsuccessfully.
  790. ; If successfully, the device is configured and ready to work,
  791. ; pass the device to the corresponding driver(s).
  792. proc usb_got_config_callback stdcall, pipe:dword, status:dword, buffer:dword, length:dword, calldata:dword
  793. locals
  794. InterfacesData  dd      ?
  795. NumInterfaces   dd      ?
  796. driver          dd      ?
  797. endl
  798. ; 1. If there was an error, say something to the debug board and stop the
  799. ; initialization.
  800.         cmp     [status], 0
  801.         jz      @f
  802.         dbgstr 'USB error in SET_CONFIGURATION'
  803.         ret
  804. @@:
  805.         push    ebx edi         ; save used registers to be stdcall
  806. ; 2. Sanity checks: the total length must be the same as before (because we
  807. ; have allocated memory assuming the old value), length of config descriptor
  808. ; must be at least sizeof.usb_config_descr (we use fields from it),
  809. ; there must be at least one interface.
  810.         mov     ebx, [pipe]
  811.         mov     ebx, [ebx+usb_pipe.DeviceData]
  812.         mov     eax, [calldata]
  813.         mov     edx, [ebx+usb_device_data.ConfigDataSize]
  814.         cmp     [eax+usb_config_descr.wTotalLength], dx
  815.         jnz     .invalid
  816.         cmp     [eax+usb_config_descr.bLength], 9
  817.         jb      .invalid
  818.         movzx   edx, [eax+usb_config_descr.bNumInterfaces]
  819.         test    edx, edx
  820.         jnz     @f
  821. .invalid:
  822.         dbgstr 'error: invalid configuration descriptor'
  823.         jmp     .nothing
  824. @@:
  825. ; 3. Store the number of interfaces in device data structure.
  826.         mov     [ebx+usb_device_data.NumInterfaces], edx
  827. ; 4. If there is only one interface (which happens quite often),
  828. ; the memory allocated in usb_know_length_callback is sufficient.
  829. ; Otherwise (which also happens quite often), reallocate device data.
  830. ; 4a. Check whether there is only one interface. If so, skip this step.
  831.         cmp     edx, 1
  832.         jz      .has_memory
  833. ; 4b. Allocate new memory.
  834.         mov     eax, [ebx+usb_device_data.Interfaces]
  835.         lea     eax, [eax+edx*sizeof.usb_interface_data]
  836.         call    malloc
  837. ; 4c. If failed, say something to the debug board and
  838. ; stop the initialization.
  839.         test    eax, eax
  840.         jnz     @f
  841.         dbgstr 'No memory for device data'
  842.         jmp     .nothing
  843. @@:
  844. ; 4d. Copy data from old memory to new memory and switch the pointer in usb_pipe.
  845.         push    eax
  846.         push    esi
  847.         mov     ebx, [pipe]
  848.         mov     edi, eax
  849.         mov     esi, [ebx+usb_pipe.DeviceData]
  850.         mov     [ebx+usb_pipe.DeviceData], eax
  851.         mov     eax, esi
  852.         mov     ecx, [esi+usb_device_data.Interfaces]
  853.         shr     ecx, 2
  854.         rep movsd
  855.         pop     esi
  856.         call    usb_reinit_pipe_list
  857. ; 4e. Free old memory.
  858.         call    free
  859.         pop     ebx
  860. .has_memory:
  861. ; 5. Initialize interfaces table: zero all contents.
  862.         mov     edi, [ebx+usb_device_data.Interfaces]
  863.         add     edi, ebx
  864.         mov     [InterfacesData], edi
  865.         mov     ecx, [ebx+usb_device_data.NumInterfaces]
  866. if sizeof.usb_interface_data <> 8
  867. You have changed sizeof.usb_interface_data? Modify this place too.
  868. end if
  869.         add     ecx, ecx
  870.         xor     eax, eax
  871.         rep stosd
  872. ; No interfaces are found yet.
  873.         mov     [NumInterfaces], eax
  874. ; 6. Get the pointer to config descriptor data.
  875. ; Note: if there was reallocation, [buffer] is not valid anymore,
  876. ; so calculate value based on usb_device_data.
  877.         movzx   eax, [ebx+usb_device_data.DeviceDescrSize]
  878.         lea     eax, [eax+ebx+sizeof.usb_device_data]
  879.         mov     [calldata], eax
  880.         mov     ecx, [ebx+usb_device_data.ConfigDataSize]
  881. ; 7. Loop over all descriptors,
  882. ; scan for interface descriptors with bAlternateSetting = 0,
  883. ; load the corresponding driver, call its AddDevice function.
  884. .descriptor_loop:
  885. ; While in loop: eax points to the current descriptor,
  886. ; ecx = number of bytes left, the iteration starts only if ecx is nonzero,
  887. ; edx = size of the current descriptor.
  888. ; 7a. The first byte is always accessible; it contains the length of
  889. ; the current descriptor. Validate that the length is at least 2 bytes,
  890. ; and the entire descriptor is readable (the length is at most number of
  891. ; bytes left).
  892.         movzx   edx, [eax+usb_descr.bLength]
  893.         cmp     edx, sizeof.usb_descr
  894.         jb      .invalid
  895.         cmp     ecx, edx
  896.         jb      .invalid
  897. ; 7b. Check descriptor type. Ignore all non-INTERFACE descriptor.
  898.         cmp     byte [eax+usb_descr.bDescriptorType], USB_INTERFACE_DESCR
  899.         jz      .interface
  900. .next_descriptor:
  901. ; 7c. Advance pointer, decrease length left, if there is still something left,
  902. ; continue the loop.
  903.         add     eax, edx
  904.         sub     ecx, edx
  905.         jnz     .descriptor_loop
  906. .done:
  907. .nothing:
  908.         pop     edi ebx         ; restore used registers to be stdcall
  909.         ret
  910. .interface:
  911. ; 7d. Validate the descriptor length.
  912.         cmp     edx, sizeof.usb_interface_descr
  913.         jb      .next_descriptor
  914. ; 7e. If bAlternateSetting is nonzero, this descriptor actually describes
  915. ; another mode of already known interface and belongs to the already loaded
  916. ; driver; amuse the user and continue to 7c.
  917.         cmp     byte [eax+usb_interface_descr.bAlternateSetting], 0
  918.         jz      @f
  919.         DEBUGF 1,'K : note: alternate setting with %x/%x/%x\n',\
  920.                 [eax+usb_interface_descr.bInterfaceClass]:2,\
  921.                 [eax+usb_interface_descr.bInterfaceSubClass]:2,\
  922.                 [eax+usb_interface_descr.bInterfaceProtocol]:2
  923.         jmp     .next_descriptor
  924. @@:
  925. ; 7f. Check that the new interface does not overflow allocated table.
  926.         mov     edx, [NumInterfaces]
  927.         inc     edx
  928.         cmp     edx, [ebx+usb_device_data.NumInterfaces]
  929.         ja      .invalid
  930. ; 7g. We have found a new interface. Advance bookkeeping vars.
  931.         mov     [NumInterfaces], edx
  932.         add     [InterfacesData], sizeof.usb_interface_data
  933. ; 7h. Save length left and pointer to the current interface descriptor.
  934.         push    ecx eax
  935. ; Amuse the user if she is watching the debug board.
  936.         DEBUGF 1,'K : USB interface class/subclass/protocol = %x/%x/%x\n',\
  937.                 [eax+usb_interface_descr.bInterfaceClass]:2,\
  938.                 [eax+usb_interface_descr.bInterfaceSubClass]:2,\
  939.                 [eax+usb_interface_descr.bInterfaceProtocol]:2
  940. ; 7i. Select the correct driver based on interface class.
  941. ; For hubs, go to 7j. Otherwise, go to 7k.
  942. ; Note: this should be rewritten as table-based lookup when more drivers will
  943. ; be available.
  944.         cmp     byte [eax+usb_interface_descr.bInterfaceClass], 9
  945.         jz      .found_hub
  946.         mov     edx, usb_hid_name
  947.         cmp     byte [eax+usb_interface_descr.bInterfaceClass], 3
  948.         jz      .load_driver
  949.         mov     edx, usb_print_name
  950.         cmp     byte [eax+usb_interface_descr.bInterfaceClass], 7
  951.         jz      .load_driver
  952.         mov     edx, usb_stor_name
  953.         cmp     byte [eax+usb_interface_descr.bInterfaceClass], 8
  954.         jz      .load_driver
  955.         mov     edx, usb_other_name
  956.         jmp     .load_driver
  957. .found_hub:
  958. ; 7j. Hubs are a part of USB stack, thus, integrated into the kernel.
  959. ; Use the pointer to hub callbacks and go to 7m.
  960.         mov     eax, usb_hub_pseudosrv - USBSRV.usb_func
  961.         jmp     .driver_loaded
  962. .load_driver:
  963. ; 7k. Load the corresponding driver.
  964.         push    ebx esi edi
  965.         stdcall get_service, edx
  966.         pop     edi esi ebx
  967. ; 7l. If failed, say something to the debug board and go to 7p.
  968.         test    eax, eax
  969.         jnz     .driver_loaded
  970.         dbgstr 'failed to load class driver'
  971.         jmp     .next_descriptor2
  972. .driver_loaded:
  973. ; 7m. Call AddDevice function of the driver.
  974. ; Note that top of stack contains a pointer to the current interface,
  975. ; saved by step 7h.
  976.         mov     [driver], eax
  977.         mov     eax, [eax+USBSRV.usb_func]
  978.         pop     edx
  979.         push    edx
  980. ; Note: usb_hub_init assumes that edx points to usb_interface_descr,
  981. ; ecx = length rest; if you change the code, modify usb_hub_init also.
  982.         stdcall [eax+USBFUNC.add_device], [pipe], [calldata], edx
  983. ; 7n. If failed, say something to the debug board and go to 7p.
  984.         test    eax, eax
  985.         jnz     .store_data
  986.         dbgstr 'USB device initialization failed'
  987.         jmp     .next_descriptor2
  988. .store_data:
  989. ; 7o. Store the returned value and the driver handle to InterfacesData.
  990. ; Note that step 7g has already advanced InterfacesData.
  991.         mov     edx, [InterfacesData]
  992.         mov     [edx+usb_interface_data.DriverData-sizeof.usb_interface_data], eax
  993.         mov     eax, [driver]
  994.         mov     [edx+usb_interface_data.DriverFunc-sizeof.usb_interface_data], eax
  995. .next_descriptor2:
  996. ; 7p. Restore registers saved in step 7h, get the descriptor length and
  997. ; continue to 7c.
  998.         pop     eax ecx
  999.         movzx   edx, byte [eax+usb_descr.bLength]
  1000.         jmp     .next_descriptor
  1001. endp
  1002.  
  1003. ; Driver names, see step 7i of usb_got_config_callback.
  1004. iglobal
  1005. usb_hid_name    db      'usbhid',0
  1006. usb_stor_name   db      'usbstor',0
  1007. usb_print_name  db      'usbprint',0
  1008. usb_other_name  db      'usbother',0
  1009. endg
  1010.