audio_fw.c

Minix比较全的源码

	chan = special_file_ptr->read_chan;

	if (chan == NO_CHANNEL) {
		error("%s: No read channel specified!\n", drv.DriverName);
		reply(TASK_REPLY, m_ptr->m_source, m_ptr->IO_ENDPT, EIO);
		return;
	}
	/* get pointer to sub device data */
	sub_dev_ptr = &sub_dev[chan];

	if (!sub_dev_ptr->DmaBusy) { /* get fragment size on first read */
		if (drv_get_frag_size(&(sub_dev_ptr->FragSize), sub_dev_ptr->Nr) != OK){
			error("%s: Could not retrieve fragment size!\n", drv.DriverName);
			reply(TASK_REPLY, m_ptr->m_source, m_ptr->IO_ENDPT, EIO);      	
			return;
		}
	}
	if(m_ptr->COUNT != sub_dev_ptr->FragSize) {
		reply(TASK_REPLY, m_ptr->m_source, m_ptr->IO_ENDPT, EINVAL);
		error("fragment size does not match message size\n");
		return;
	}
	/* if we are busy with something else than reading, reply EBUSY */
	if(sub_dev_ptr->DmaBusy && sub_dev_ptr->DmaMode != DEV_READ_S) {
		reply(TASK_REPLY, m_ptr->m_source, m_ptr->IO_ENDPT, EBUSY);
		return;
	}
	/* unblock the FileSystem, but keep user process blocked until REVIVE*/
	reply(TASK_REPLY, m_ptr->m_source, m_ptr->IO_ENDPT, SUSPEND);
	sub_dev_ptr->RevivePending = TRUE;
	sub_dev_ptr->ReviveProcNr = m_ptr->IO_ENDPT;
	sub_dev_ptr->ReviveGrant = (cp_grant_id_t) m_ptr->ADDRESS;
	sub_dev_ptr->NotifyProcNr = m_ptr->m_source;

	if(!sub_dev_ptr->DmaBusy) { /* Dma tranfer not yet started */
		get_started(sub_dev_ptr);
		sub_dev_ptr->DmaMode = DEV_READ_S; /* Dma mode is reading */
		return;  /* no need to get data from DMA buffer at this point */
	}
	/* check if data is available and possibly fill user's buffer */
	data_to_user(sub_dev_ptr);
}


PRIVATE void msg_hardware(void) {

	u32_t     i;
	int j = 0;

	dprint("%s: handling hardware message\n", drv.DriverName);

	/* while we have an interrupt  */
	while ( drv_int_sum()) {
		/* loop over all sub devices */
		for ( i = 0; i < drv.NrOfSubDevices; i++) {
			/* if interrupt from sub device and Dma transfer 
			   was actually busy, take care of business */
			if( drv_int(i) && sub_dev[i].DmaBusy ) {
				if (sub_dev[i].DmaMode == DEV_WRITE_S) handle_int_write(i);
				if (sub_dev[i].DmaMode == DEV_READ_S) handle_int_read(i);  
			}
		}
	}

	/* As IRQ_REENABLE is not on in sys_irqsetpolicy, we must
	 * re-enable out interrupt after every interrupt.
	 */
	if ((sys_irqenable(&irq_hook_id)) != OK) {
	  error("%s: msg_hardware: Couldn't enable IRQ\n", drv.DriverName);
	}
}


PRIVATE void msg_status(message *m_ptr)
{
	int i; 

	dprint("got a status message\n");
	for (i = 0; i < drv.NrOfSubDevices; i++) {

		if(sub_dev[i].ReadyToRevive) 
		{
			m_ptr->m_type = DEV_REVIVE;			/* build message */
			m_ptr->REP_ENDPT = sub_dev[i].ReviveProcNr;
			m_ptr->REP_IO_GRANT = sub_dev[i].ReviveGrant;
			m_ptr->REP_STATUS = sub_dev[i].ReviveStatus;
			send(m_ptr->m_source, m_ptr);			/* send the message */

			/* reset variables */
			sub_dev[i].ReadyToRevive = FALSE;
			sub_dev[i].RevivePending = 0;

			return; /* stop after one mess, 
					   file system will get back for other processes */
		}
	}
	m_ptr->m_type = DEV_NO_STATUS;
	m_ptr->REP_STATUS = 0;
	send(m_ptr->m_source, m_ptr);			/* send DEV_NO_STATUS message */
}


PRIVATE void msg_sig_stop(void) 
{
	int i; char irq;
	for (i = 0; i < drv.NrOfSubDevices; i++) {
		drv_stop(i); /* stop all sub devices */
	}
	if (irq_hook_set) {
		if (sys_irqdisable(&irq_hook_id) != OK) {
			error("Could not disable IRQ\n");
		}
		/* get irq from device driver*/
		if (drv_get_irq(&irq) != OK) {
			error("Msg SIG_STOP Couldn't get IRQ");
		}
		/* remove the policy */
		if (sys_irqrmpolicy(irq, &irq_hook_id) != OK) {
			error("%s: Could not disable IRQ\n",drv.DriverName);
		}
	}
}


/* handle interrupt for specified sub device; DmaMode == DEV_WRITE_S*/
PRIVATE void handle_int_write(int sub_dev_nr) 
{
	sub_dev_t *sub_dev_ptr;
	int r;

	sub_dev_ptr = &sub_dev[sub_dev_nr];

	dprint("Finished playing dma[%d] ", sub_dev_ptr->DmaReadNext);
	sub_dev_ptr->DmaReadNext = 
		(sub_dev_ptr->DmaReadNext + 1) % sub_dev_ptr->NrOfDmaFragments;
	sub_dev_ptr->DmaLength -= 1;

	if (sub_dev_ptr->BufLength != 0) { /* Data in extra buf, copy to Dma buf */

		dprint(" buf[%d] -> dma[%d] ", 
				sub_dev_ptr->BufReadNext, sub_dev_ptr->DmaFillNext);
		memcpy(sub_dev_ptr->DmaPtr + 
				sub_dev_ptr->DmaFillNext * sub_dev_ptr->FragSize, 
				sub_dev_ptr->ExtraBuf + 
				sub_dev_ptr->BufReadNext * sub_dev_ptr->FragSize, 
				sub_dev_ptr->FragSize);

		sub_dev_ptr->BufReadNext = 
			(sub_dev_ptr->BufReadNext + 1) % sub_dev_ptr->NrOfExtraBuffers;
		sub_dev_ptr->DmaFillNext = 
			(sub_dev_ptr->DmaFillNext + 1) % sub_dev_ptr->NrOfDmaFragments;

		sub_dev_ptr->BufLength -= 1;
		sub_dev_ptr->DmaLength += 1;
	} 

	/* space became available, possibly copy new data from user */
	data_from_user(sub_dev_ptr);

	if(sub_dev_ptr->DmaLength == 0) { /* Dma buffer empty, stop Dma transfer */

		sub_dev_ptr->OutOfData = TRUE; /* we're out of data */
		dprint("No more work...!\n");
		if (!sub_dev_ptr->Opened) {
			close_sub_dev(sub_dev_ptr->Nr);
			dprint("Stopping sub device %d\n", sub_dev_ptr->Nr);
			return;
		}
		dprint("Pausing sub device %d\n",sub_dev_ptr->Nr);
		drv_pause(sub_dev_ptr->Nr);
		return;
	}

	dprint("\n");

	/* confirm and reenable interrupt from this sub dev */
	drv_reenable_int(sub_dev_nr);
#if 0
	/* reenable irq_hook*/
	if ((r=sys_irqenable(&irq_hook_id)) != OK) {
		error("%s Couldn't enable IRQ\n", drv.DriverName);
	}
#endif
}


/* handle interrupt for specified sub device; DmaMode == DEV_READ_S */
PRIVATE void handle_int_read(int sub_dev_nr) 
{
	sub_dev_t *sub_dev_ptr; int r,i;

	sub_dev_ptr = &sub_dev[sub_dev_nr];

	dprint("Device filled dma[%d]\n", sub_dev_ptr->DmaFillNext);
	sub_dev_ptr->DmaLength += 1; 
	sub_dev_ptr->DmaFillNext = 
		(sub_dev_ptr->DmaFillNext + 1) % sub_dev_ptr->NrOfDmaFragments;

	/* possibly copy data to user (if it is waiting for us) */
	data_to_user(sub_dev_ptr);

	if (sub_dev_ptr->DmaLength == sub_dev_ptr->NrOfDmaFragments) { 
		/* if dma buffer full */

		if (sub_dev_ptr->BufLength == sub_dev_ptr->NrOfExtraBuffers) {
			error("All buffers full, we have a problem.\n");
			drv_stop(sub_dev_nr);        /* stop the sub device */
			sub_dev_ptr->DmaBusy = FALSE;
			sub_dev_ptr->ReviveStatus = 0;   /* no data for user, 
												this is a sad story */
			sub_dev_ptr->ReadyToRevive = TRUE; /* wake user up */
			return;
		} 
		else { /* dma full, still room in extra buf; 
				  copy from dma to extra buf */
			dprint("dma full: going to copy buf[%d] <- dma[%d]\n", 
					sub_dev_ptr->BufFillNext, sub_dev_ptr->DmaReadNext);
			memcpy(sub_dev_ptr->ExtraBuf + 
					sub_dev_ptr->BufFillNext * sub_dev_ptr->FragSize, 
					sub_dev_ptr->DmaPtr + 
					sub_dev_ptr->DmaReadNext * sub_dev_ptr->FragSize,
					sub_dev_ptr->FragSize);
			sub_dev_ptr->DmaLength -= 1;
			sub_dev_ptr->DmaReadNext = 
				(sub_dev_ptr->DmaReadNext + 1) % sub_dev_ptr->NrOfDmaFragments;
			sub_dev_ptr->BufFillNext = 
				(sub_dev_ptr->BufFillNext + 1) % sub_dev_ptr->NrOfExtraBuffers;
		}
	}
	/* confirm interrupt, and reenable interrupt from this sub dev*/
	drv_reenable_int(sub_dev_ptr->Nr);

#if 0
	/* reenable irq_hook*/
	if ((r=sys_irqenable(&irq_hook_id)) != OK) {
		error("%s: Couldn't reenable IRQ", drv.DriverName);
	}
#endif
}


PRIVATE int get_started(sub_dev_t *sub_dev_ptr) {
	u32_t i;char c;  

	/* enable interrupt messages from MINIX */
	if ((i=sys_irqenable(&irq_hook_id)) != OK) {
		error("%s: Couldn't enable IRQs",drv.DriverName);
		return EIO;
	}
	/* let the lower part of the driver start the device */
	if (drv_start(sub_dev_ptr->Nr, sub_dev_ptr->DmaMode) != OK) {
		error("%s: Could not start device %d\n", 
				drv.DriverName, sub_dev_ptr->Nr);
	}

	sub_dev_ptr->DmaBusy = TRUE;     /* Dma is busy from now on */
	sub_dev_ptr->DmaReadNext = 0;    
	return OK;
}


PRIVATE void data_from_user(sub_dev_t *subdev)
{

	if (subdev->DmaLength == subdev->NrOfDmaFragments &&
			subdev->BufLength == subdev->NrOfExtraBuffers) return;/* no space */

	if (!subdev->RevivePending) return; /* no new data waiting to be copied */

	if (subdev->RevivePending && 
			subdev->ReadyToRevive) return; /* we already got this data */

	if (subdev->DmaLength < subdev->NrOfDmaFragments) { /* room in dma buf */

		sys_safecopyfrom(subdev->ReviveProcNr, 
				(vir_bytes)subdev->ReviveGrant, 0, 
				(vir_bytes)subdev->DmaPtr + 
				subdev->DmaFillNext * subdev->FragSize,
				(phys_bytes)subdev->FragSize, D);


		dprint(" user -> dma[%d]\n", subdev->DmaFillNext);
		subdev->DmaLength += 1;
		subdev->DmaFillNext = 
			(subdev->DmaFillNext + 1) % subdev->NrOfDmaFragments;

	} else { /* room in extra buf */ 

		sys_safecopyfrom(subdev->ReviveProcNr, 
				(vir_bytes)subdev->ReviveGrant, 0,
				(vir_bytes)subdev->ExtraBuf + 
				subdev->BufFillNext * subdev->FragSize, 
				(phys_bytes)subdev->FragSize, D);

		dprint(" user -> buf[%d]\n", subdev->BufFillNext);
		subdev->BufLength += 1;

		subdev->BufFillNext = 
			(subdev->BufFillNext + 1) % subdev->NrOfExtraBuffers;

	}
	if(subdev->OutOfData) { /* if device paused (because of lack of data) */
		subdev->OutOfData = FALSE;
		drv_reenable_int(subdev->Nr);
		/* reenable irq_hook*/
		if ((sys_irqenable(&irq_hook_id)) != OK) {
			error("%s: Couldn't enable IRQ", drv.DriverName);
		}
		drv_resume(subdev->Nr);  /* resume resume the sub device */
	}

	subdev->ReviveStatus = subdev->FragSize;
	subdev->ReadyToRevive = TRUE;
	notify(subdev->NotifyProcNr);
}


PRIVATE void data_to_user(sub_dev_t *sub_dev_ptr) {
	if (!sub_dev_ptr->RevivePending) return; /* nobody is wating for data */
	if (sub_dev_ptr->ReadyToRevive) return;/* we already filled user's buffer */
	if (sub_dev_ptr->BufLength == 0 && sub_dev_ptr->DmaLength == 0) return; 
		/* no data for user */

	if(sub_dev_ptr->BufLength != 0) { /* data in extra buffer available */

		sys_safecopyto(sub_dev_ptr->ReviveProcNr, 
				(vir_bytes)sub_dev_ptr->ReviveGrant,
				0, (vir_bytes)sub_dev_ptr->ExtraBuf + 
				sub_dev_ptr->BufReadNext * sub_dev_ptr->FragSize,
				(phys_bytes)sub_dev_ptr->FragSize, D);

		dprint(" copied buf[%d] to user\n", sub_dev_ptr->BufReadNext); 

		/* adjust the buffer status variables */
		sub_dev_ptr->BufReadNext = 
			(sub_dev_ptr->BufReadNext + 1) % sub_dev_ptr->NrOfExtraBuffers;
		sub_dev_ptr->BufLength -= 1;

	} else { /* extra buf empty, but data in dma buf*/ 
		sys_safecopyto(
				sub_dev_ptr->ReviveProcNr, 
				(vir_bytes)sub_dev_ptr->ReviveGrant, 0, 
				(vir_bytes)sub_dev_ptr->DmaPtr + 
				sub_dev_ptr->DmaReadNext * sub_dev_ptr->FragSize,
				(phys_bytes)sub_dev_ptr->FragSize, D);

		dprint(" copied dma[%d] to user\n", sub_dev_ptr->DmaReadNext);

		/* adjust the buffer status variables */
		sub_dev_ptr->DmaReadNext = 
			(sub_dev_ptr->DmaReadNext + 1) % sub_dev_ptr->NrOfDmaFragments;
		sub_dev_ptr->DmaLength -= 1;
	}

	sub_dev_ptr->ReviveStatus = sub_dev_ptr->FragSize;
	sub_dev_ptr->ReadyToRevive = TRUE; 
		/* drv_status will send REVIVE mess to FS*/	
	notify(sub_dev_ptr->NotifyProcNr);     /* notify the File Systam to make it 
											  send DEV_STATUS messages*/
}


	PRIVATE int init_buffers(sub_dev_t *sub_dev_ptr) {
#if (CHIP == INTEL)
		unsigned left;
		u32_t i;

		/* allocate dma buffer space */
		if (!(sub_dev_ptr->DmaBuf = malloc(sub_dev_ptr->DmaSize + 64 * 1024))) {
			error("%s: failed to allocate dma buffer for channel %d\n", 
					drv.DriverName,i);
			return EIO;
		}
		/* allocate extra buffer space */
		if (!(sub_dev_ptr->ExtraBuf = malloc(sub_dev_ptr->NrOfExtraBuffers * 
						sub_dev_ptr->DmaSize / 
						sub_dev_ptr->NrOfDmaFragments))) {
			error("%s failed to allocate extra buffer for channel %d\n", 
					drv.DriverName,i);
			return EIO;
		}

		sub_dev_ptr->DmaPtr = sub_dev_ptr->DmaBuf;
		i = sys_umap(SELF, D, 
				(vir_bytes) sub_dev_ptr->DmaBuf, 
				(phys_bytes) sizeof(sub_dev_ptr->DmaBuf), 
				&(sub_dev_ptr->DmaPhys));

		if (i != OK) {
			return EIO;
		}
		if ((left = dma_bytes_left(sub_dev_ptr->DmaPhys)) < 
				sub_dev_ptr->DmaSize) {
			/* First half of buffer crosses a 64K boundary,
			 * can't DMA into that */
			sub_dev_ptr->DmaPtr += left;
			sub_dev_ptr->DmaPhys += left;
		}
		/* write the physical dma address and size to the device */
		drv_set_dma(sub_dev_ptr->DmaPhys, 
				sub_dev_ptr->DmaSize, sub_dev_ptr->Nr);
		return OK;

#else /* CHIP != INTEL */
		error("%s: init_buffer() failed, CHIP != INTEL", drv.DriverName);
		return EIO;
#endif /* CHIP == INTEL */
	}


PRIVATE void reply(int code, int replyee, int process, int status) {
	message m;

	m.m_type = code;		/* TASK_REPLY or REVIVE */
	m.REP_STATUS = status;	/* result of device operation */
	m.REP_ENDPT = process;	/* which user made the request */
	send(replyee, &m);
}


PRIVATE int io_ctl_length(int io_request) {
	io_request >>= 16; 
	return io_request & _IOCPARM_MASK;
}


PRIVATE special_file_t* get_special_file(int minor_dev_nr) {
	int i;

	for(i = 0; i < drv.NrOfSpecialFiles; i++) {
		if(special_file[i].minor_dev_nr == minor_dev_nr) {
			return &special_file[i];
		}
	}

	error("%s: No subdevice specified for minor device %d!\n", 
			drv.DriverName, minor_dev_nr);

	return NULL;
}