Modules/USB/Core/usb_poll.c

   1 /*
   2  * Acess2 USB Stack
   3  * - By John Hodge (thePowersGang)
   4  *
   5  * usb_poll.c
   6  * - Endpoint polling
   7  */
   8 #define DEBUG   1
   9 #include <usb_core.h>
  10 #include "usb.h"
  11
  12 #define POLL_ATOM       25      // 25ms atom
  13 #define POLL_MAX        256     // Max period that can be nominated
  14 #define POLL_SLOTS      ((int)(POLL_MAX/POLL_ATOM))
  15
  16 // === PROTOTYPES ===
  17 void    USB_StartPollingEndpoint(tUSBInterface *Iface, int Endpoint);
  18
  19 // === GLOBALS ===
  20 tUSBEndpoint    *gUSB_PollQueues[POLL_MAX/POLL_ATOM];
  21  int    giUSB_PollPosition;     // Index into gUSB_PollQueues
  22
  23 // === CODE ===
  24 void USB_StartPollingEndpoint(tUSBInterface *Iface, int Endpoint)
  25 {
  26         tUSBEndpoint    *endpt;
  27
  28         // Some sanity checks
  29         if(Endpoint <= 0 || Endpoint > Iface->nEndpoints)       return ;
  30         endpt = &Iface->Endpoints[Endpoint-1];
  31         if(endpt->PollingPeriod > POLL_MAX || endpt->PollingPeriod <= 0)
  32                 return ;
  33
  34         // TODO: Check that this endpoint isn't already on the queue
  35
  36         endpt->InputData = malloc(endpt->MaxPacketSize);
  37
  38         // Determine polling period in atoms
  39         endpt->PollingAtoms = (endpt->PollingPeriod + POLL_ATOM-1) / POLL_ATOM;
  40         if(endpt->PollingAtoms > POLL_SLOTS)    endpt->PollingAtoms = POLL_SLOTS;
  41         // Add to poll queue
  42         // TODO: Locking
  43         {
  44                  int    idx = giUSB_PollPosition + 1;
  45                 if(idx >= POLL_SLOTS)   idx -= POLL_SLOTS;
  46                 LOG("idx = %i", idx);
  47                 endpt->Next = gUSB_PollQueues[idx];
  48                 gUSB_PollQueues[idx] = endpt;
  49         }
  50 }
  51
  52 /**
  53  * \brief USB polling thread
  54  */
  55 int USB_PollThread(void *unused)
  56 {
  57         Threads_SetName("USB Polling Thread");
  58         for(;;)
  59         {
  60                 tUSBEndpoint    *ep, *prev;
  61
  62                 // A little evil for neater code
  63                 prev = (void*)( (tVAddr)&gUSB_PollQueues[giUSB_PollPosition] - offsetof(tUSBEndpoint, Next) );
  64
  65                 // Process queue
  66 //              LOG("giUSB_PollPosition = %i", giUSB_PollPosition);
  67                 for( ep = gUSB_PollQueues[giUSB_PollPosition]; ep; prev = ep, ep = ep->Next )
  68                 {
  69                          int    period_in_atoms = ep->PollingAtoms;
  70                         LOG("%i: ep = %p", giUSB_PollPosition, ep);
  71
  72                         // Check for invalid entries
  73                         if(period_in_atoms < 0 || period_in_atoms > POLL_ATOM)
  74                         {
  75                                 Log_Warning("USB", "Endpoint on polling queue with invalid period");
  76                                 continue ;
  77                         }
  78                         // Check for entries to delete
  79                         if(period_in_atoms == 0)
  80                         {
  81                                 // Remove
  82                                 prev->Next = ep->Next;
  83                                 ep->PollingAtoms = -1;  // Mark as removed
  84                                 ep = prev;      // Make sure prev is kept valid
  85                                 continue ;
  86                         }
  87
  88                         // Read data
  89                         // TODO: Check the endpoint
  90                         // TODO: Async checking?
  91                         // - Send the read request on all of them then wait for the first to complete
  92                         USB_RecvDataA(
  93                                 ep->Interface, ep->EndpointIdx+1,
  94                                 ep->MaxPacketSize, ep->InputData,
  95                                 ep->Interface->Driver->Endpoints[ep->EndpointIdx].DataAvail
  96                                 );
  97
  98                         // Call callback
  99
 100                         // Reschedule
 101                         if( period_in_atoms != POLL_SLOTS )
 102                         {
 103                                  int    newqueue_id = (giUSB_PollPosition + period_in_atoms) % POLL_SLOTS;
 104                                 tUSBEndpoint    **newqueue = &gUSB_PollQueues[newqueue_id];
 105
 106                                 prev->Next = ep->Next;
 107
 108                                 ep->Next = *newqueue;
 109                                 *newqueue = ep;
 110                         }
 111                 }
 112                 giUSB_PollPosition ++;
 113                 if(giUSB_PollPosition == POLL_SLOTS)
 114                         giUSB_PollPosition = 0;
 115                 // TODO: Check for a longer delay
 116                 Time_Delay(POLL_ATOM);
 117         }
 118 }
 119