ibmphp_hpc.c

audio driver for hotplug pci on linux 2.6.27

				} else
					timeout--;
			}
		}
		ctlr_ptr->status = status;
	}
	// cleanup

	// remove physical to logical address mapping
	if ((ctlr_ptr->ctlr_type == 2) || (ctlr_ptr->ctlr_type == 4))
		iounmap (wpg_bbar);
	free_hpc_access ();

	debug_polling ("%s - Exit rc[%d]\n", __func__, rc);
	return rc;
}

/*----------------------------------------------------------------------
* Name:    get_hpc_access()
*
* Action: make sure only one process can access HPC at one time
*---------------------------------------------------------------------*/
static void get_hpc_access (void)
{
	mutex_lock(&sem_hpcaccess);
}

/*----------------------------------------------------------------------
* Name:    free_hpc_access()
*---------------------------------------------------------------------*/
void free_hpc_access (void)
{
	mutex_unlock(&sem_hpcaccess);
}

/*----------------------------------------------------------------------
* Name:    ibmphp_lock_operations()
*
* Action: make sure only one process can change the data structure
*---------------------------------------------------------------------*/
void ibmphp_lock_operations (void)
{
	down (&semOperations);
	to_debug = 1;
}

/*----------------------------------------------------------------------
* Name:    ibmphp_unlock_operations()
*---------------------------------------------------------------------*/
void ibmphp_unlock_operations (void)
{
	debug ("%s - Entry\n", __func__);
	up (&semOperations);
	to_debug = 0;
	debug ("%s - Exit\n", __func__);
}

/*----------------------------------------------------------------------
* Name:    poll_hpc()
*---------------------------------------------------------------------*/
#define POLL_LATCH_REGISTER	0
#define POLL_SLOTS		1
#define POLL_SLEEP		2
static int poll_hpc(void *data)
{
	struct slot myslot;
	struct slot *pslot = NULL;
	struct list_head *pslotlist;
	int rc;
	int poll_state = POLL_LATCH_REGISTER;
	u8 oldlatchlow = 0x00;
	u8 curlatchlow = 0x00;
	int poll_count = 0;
	u8 ctrl_count = 0x00;

	debug ("%s - Entry\n", __func__);

	while (!kthread_should_stop()) {
		/* try to get the lock to do some kind of hardware access */
		down (&semOperations);

		switch (poll_state) {
		case POLL_LATCH_REGISTER: 
			oldlatchlow = curlatchlow;
			ctrl_count = 0x00;
			list_for_each (pslotlist, &ibmphp_slot_head) {
				if (ctrl_count >= ibmphp_get_total_controllers())
					break;
				pslot = list_entry (pslotlist, struct slot, ibm_slot_list);
				if (pslot->ctrl->ctlr_relative_id == ctrl_count) {
					ctrl_count++;
					if (READ_SLOT_LATCH (pslot->ctrl)) {
						rc = ibmphp_hpc_readslot (pslot,
									  READ_SLOTLATCHLOWREG,
									  &curlatchlow);
						if (oldlatchlow != curlatchlow)
							process_changeinlatch (oldlatchlow,
									       curlatchlow,
									       pslot->ctrl);
					}
				}
			}
			++poll_count;
			poll_state = POLL_SLEEP;
			break;
		case POLL_SLOTS:
			list_for_each (pslotlist, &ibmphp_slot_head) {
				pslot = list_entry (pslotlist, struct slot, ibm_slot_list);
				// make a copy of the old status
				memcpy ((void *) &myslot, (void *) pslot,
					sizeof (struct slot));
				rc = ibmphp_hpc_readslot (pslot, READ_ALLSTAT, NULL);
				if ((myslot.status != pslot->status)
				    || (myslot.ext_status != pslot->ext_status))
					process_changeinstatus (pslot, &myslot);
			}
			ctrl_count = 0x00;
			list_for_each (pslotlist, &ibmphp_slot_head) {
				if (ctrl_count >= ibmphp_get_total_controllers())
					break;
				pslot = list_entry (pslotlist, struct slot, ibm_slot_list);
				if (pslot->ctrl->ctlr_relative_id == ctrl_count) {
					ctrl_count++;
					if (READ_SLOT_LATCH (pslot->ctrl))
						rc = ibmphp_hpc_readslot (pslot,
									  READ_SLOTLATCHLOWREG,
									  &curlatchlow);
				}
			}
			++poll_count;
			poll_state = POLL_SLEEP;
			break;
		case POLL_SLEEP:
			/* don't sleep with a lock on the hardware */
			up (&semOperations);
			msleep(POLL_INTERVAL_SEC * 1000);

			if (kthread_should_stop())
				break;
			
			down (&semOperations);
			
			if (poll_count >= POLL_LATCH_CNT) {
				poll_count = 0;
				poll_state = POLL_SLOTS;
			} else
				poll_state = POLL_LATCH_REGISTER;
			break;
		}	
		/* give up the hardware semaphore */
		up (&semOperations);
		/* sleep for a short time just for good measure */
		msleep(100);
	}
	up (&sem_exit);
	debug ("%s - Exit\n", __func__);
	return 0;
}


/*----------------------------------------------------------------------
* Name:    process_changeinstatus
*
* Action:  compare old and new slot status, process the change in status
*
* Input:   pointer to slot struct, old slot struct
*
* Return   0 or error codes
* Value:
*
* Side
* Effects: None.
*
* Notes:
*---------------------------------------------------------------------*/
static int process_changeinstatus (struct slot *pslot, struct slot *poldslot)
{
	u8 status;
	int rc = 0;
	u8 disable = 0;
	u8 update = 0;

	debug ("process_changeinstatus - Entry pslot[%p], poldslot[%p]\n", pslot, poldslot);

	// bit 0 - HPC_SLOT_POWER
	if ((pslot->status & 0x01) != (poldslot->status & 0x01))
		update = 1;

	// bit 1 - HPC_SLOT_CONNECT
	// ignore

	// bit 2 - HPC_SLOT_ATTN
	if ((pslot->status & 0x04) != (poldslot->status & 0x04))
		update = 1;

	// bit 3 - HPC_SLOT_PRSNT2
	// bit 4 - HPC_SLOT_PRSNT1
	if (((pslot->status & 0x08) != (poldslot->status & 0x08))
		|| ((pslot->status & 0x10) != (poldslot->status & 0x10)))
		update = 1;

	// bit 5 - HPC_SLOT_PWRGD
	if ((pslot->status & 0x20) != (poldslot->status & 0x20))
		// OFF -> ON: ignore, ON -> OFF: disable slot
		if ((poldslot->status & 0x20) && (SLOT_CONNECT (poldslot->status) == HPC_SLOT_CONNECTED) && (SLOT_PRESENT (poldslot->status))) 
			disable = 1;

	// bit 6 - HPC_SLOT_BUS_SPEED
	// ignore

	// bit 7 - HPC_SLOT_LATCH
	if ((pslot->status & 0x80) != (poldslot->status & 0x80)) {
		update = 1;
		// OPEN -> CLOSE
		if (pslot->status & 0x80) {
			if (SLOT_PWRGD (pslot->status)) {
				// power goes on and off after closing latch
				// check again to make sure power is still ON
				msleep(1000);
				rc = ibmphp_hpc_readslot (pslot, READ_SLOTSTATUS, &status);
				if (SLOT_PWRGD (status))
					update = 1;
				else	// overwrite power in pslot to OFF
					pslot->status &= ~HPC_SLOT_POWER;
			}
		}
		// CLOSE -> OPEN 
		else if ((SLOT_PWRGD (poldslot->status) == HPC_SLOT_PWRGD_GOOD)
			&& (SLOT_CONNECT (poldslot->status) == HPC_SLOT_CONNECTED) && (SLOT_PRESENT (poldslot->status))) {
			disable = 1;
		}
		// else - ignore
	}
	// bit 4 - HPC_SLOT_BLINK_ATTN
	if ((pslot->ext_status & 0x08) != (poldslot->ext_status & 0x08))
		update = 1;

	if (disable) {
		debug ("process_changeinstatus - disable slot\n");
		pslot->flag = 0;
		rc = ibmphp_do_disable_slot (pslot);
	}

	if (update || disable) {
		ibmphp_update_slot_info (pslot);
	}

	debug ("%s - Exit rc[%d] disable[%x] update[%x]\n", __func__, rc, disable, update);

	return rc;
}

/*----------------------------------------------------------------------
* Name:    process_changeinlatch
*
* Action:  compare old and new latch reg status, process the change
*
* Input:   old and current latch register status
*
* Return   0 or error codes
* Value:
*---------------------------------------------------------------------*/
static int process_changeinlatch (u8 old, u8 new, struct controller *ctrl)
{
	struct slot myslot, *pslot;
	u8 i;
	u8 mask;
	int rc = 0;

	debug ("%s - Entry old[%x], new[%x]\n", __func__, old, new);
	// bit 0 reserved, 0 is LSB, check bit 1-6 for 6 slots

	for (i = ctrl->starting_slot_num; i <= ctrl->ending_slot_num; i++) {
		mask = 0x01 << i;
		if ((mask & old) != (mask & new)) {
			pslot = ibmphp_get_slot_from_physical_num (i);
			if (pslot) {
				memcpy ((void *) &myslot, (void *) pslot, sizeof (struct slot));
				rc = ibmphp_hpc_readslot (pslot, READ_ALLSTAT, NULL);
				debug ("%s - call process_changeinstatus for slot[%d]\n", __func__, i);
				process_changeinstatus (pslot, &myslot);
			} else {
				rc = -EINVAL;
				err ("%s - Error bad pointer for slot[%d]\n", __func__, i);
			}
		}
	}
	debug ("%s - Exit rc[%d]\n", __func__, rc);
	return rc;
}

/*----------------------------------------------------------------------
* Name:    ibmphp_hpc_start_poll_thread
*
* Action:  start polling thread
*---------------------------------------------------------------------*/
int __init ibmphp_hpc_start_poll_thread (void)
{
	debug ("%s - Entry\n", __func__);

	ibmphp_poll_thread = kthread_run(poll_hpc, NULL, "hpc_poll");
	if (IS_ERR(ibmphp_poll_thread)) {
		err ("%s - Error, thread not started\n", __func__);
		return PTR_ERR(ibmphp_poll_thread);
	}
	return 0;
}

/*----------------------------------------------------------------------
* Name:    ibmphp_hpc_stop_poll_thread
*
* Action:  stop polling thread and cleanup
*---------------------------------------------------------------------*/
void __exit ibmphp_hpc_stop_poll_thread (void)
{
	debug ("%s - Entry\n", __func__);

	kthread_stop(ibmphp_poll_thread);
	debug ("before locking operations \n");
	ibmphp_lock_operations ();
	debug ("after locking operations \n");
	
	// wait for poll thread to exit
	debug ("before sem_exit down \n");
	down (&sem_exit);
	debug ("after sem_exit down \n");

	// cleanup
	debug ("before free_hpc_access \n");
	free_hpc_access ();
	debug ("after free_hpc_access \n");
	ibmphp_unlock_operations ();
	debug ("after unlock operations \n");
	up (&sem_exit);
	debug ("after sem exit up\n");

	debug ("%s - Exit\n", __func__);
}

/*----------------------------------------------------------------------
* Name:    hpc_wait_ctlr_notworking
*
* Action:  wait until the controller is in a not working state
*
* Return   0, HPC_ERROR
* Value:
*---------------------------------------------------------------------*/
static int hpc_wait_ctlr_notworking (int timeout, struct controller *ctlr_ptr, void __iomem *wpg_bbar,
				    u8 * pstatus)
{
	int rc = 0;
	u8 done = 0;

	debug_polling ("hpc_wait_ctlr_notworking - Entry timeout[%d]\n", timeout);

	while (!done) {
		*pstatus = ctrl_read (ctlr_ptr, wpg_bbar, WPG_CTLR_INDEX);
		if (*pstatus == HPC_ERROR) {
			rc = HPC_ERROR;
			done = 1;
		}
		if (CTLR_WORKING (*pstatus) == HPC_CTLR_WORKING_NO)
			done = 1;
		if (!done) {
			msleep(1000);
			if (timeout < 1) {
				done = 1;
				err ("HPCreadslot - Error ctlr timeout\n");
				rc = HPC_ERROR;
			} else
				timeout--;
		}
	}
	debug_polling ("hpc_wait_ctlr_notworking - Exit rc[%x] status[%x]\n", rc, *pstatus);
	return rc;
}