/** gpsdrv_release Function
* This function will un-registers from the ST driver.
*
* Parameters :
* @file : File pointer for GPS char driver
* @inod :
* Returns GPS_SUCCESS - on success
* else suitable error code
*/
int gpsdrv_release(struct inode *inod, struct file *file)
{
struct gpsdrv_data *hgps = file->private_data;
GPSDRV_DBG(" Inside %s", __func__);
/* Disabling task-let 1st & then un-reg to avoid
* tasklet getting scheduled
*/
tasklet_disable(&hgps->gpsdrv_tx_tsklet);
tasklet_kill(&hgps->gpsdrv_tx_tsklet);
/* Cleat registered bit if already registered */
if (test_and_clear_bit(GPS_ST_REGISTERED, &hgps->state)) {
if (st_unregister(&gpsdrv_proto) < 0) {
GPSDRV_ERR(" st_unregister failed");
/* Re-Enable the task-let if un-register fails */
tasklet_enable(&hgps->gpsdrv_tx_tsklet);
return GPS_ERR_FAILURE;
}
}
/* Reset Tx count value and st_write function pointer */
hgps->tx_count = 0;
hgps->st_write = NULL;
clear_bit(GPS_ST_RUNNING, &hgps->state);
GPSDRV_VER(" st_unregister success");
skb_queue_purge(&hgps->rx_list);
skb_queue_purge(&hgps->tx_list);
kfree(hgps);
file->private_data = NULL;
return GPS_SUCCESS;
}
/** gpsdrv_tsklet_write Function
* This tasklet function will be scheduled when there is a data in Tx queue
* and GPS chip sent an command completion packet with non zero value.
*
* Parameters :
* @data : data passed to tasklet function
* Returns : NULL
*/
void gpsdrv_tsklet_write(unsigned long data)
{
struct sk_buff *skb = NULL;
struct gpsdrv_data *hgps = (struct gpsdrv_data *)data;
GPSDRV_DBG(" Inside %s", __func__);
spin_lock(&hgps->lock);
/* Perform sanity check of verifying the status
to perform an st_write */
if (((!hgps->st_write) || (0 == hgps->tx_count))
|| ((skb_queue_empty(&hgps->tx_list)))) {
spin_unlock(&hgps->lock);
GPSDRV_ERR("Sanity check Failed exiting %s", __func__);
return;
}
/* hgps->tx_list not empty skb already present
* dequeue the tx-data and perform a st_write
*/
hgps->tx_count--;
spin_unlock(&hgps->lock);
GPSDRV_VER(" Tx count in gpsdrv_tsklet_write = %x", hgps->tx_count);
skb = skb_dequeue(&hgps->tx_list);
hgps->st_write(skb);
return;
}
/** gpsdrv_exit Function
* This function Destroys the gps driver parametes and /dev/gps node
*
* Parameters : NULL
* Returns NULL
*/
static void __exit gpsdrv_exit(void)
{
GPSDRV_DBG(" Inside %s", __func__);
GPSDRV_VER(" Bye.. freeing up %d", gpsdrv_major);
device_destroy(gpsdrv_class, MKDEV(gpsdrv_major, 0));
class_destroy(gpsdrv_class);
unregister_chrdev(gpsdrv_major, DEVICE_NAME);
}
/** gpsdrv_init Function
* This function Initializes the gps driver parametes and exposes
* /dev/gps node to user space
*
* Parameters : NULL
* Returns GPS_SUCCESS on success
* else suitable error code
*/
static int __init gpsdrv_init(void)
{
GPSDRV_DBG(" Inside %s", __func__);
/* Expose the device DEVICE_NAME to user space
* And obtain the major number for the device
*/
gpsdrv_major = register_chrdev(0, DEVICE_NAME, \
&gpsdrv_chrdev_ops);
if (0 > gpsdrv_major) {
GPSDRV_ERR("Error when registering to char dev");
return GPS_ERR_FAILURE;
}
GPSDRV_VER("allocated %d, %d", gpsdrv_major, 0);
/* udev */
gpsdrv_class = class_create(THIS_MODULE, DEVICE_NAME);
if (IS_ERR(gpsdrv_class)) {
GPSDRV_ERR(" Something went wrong in class_create");
unregister_chrdev(gpsdrv_major, DEVICE_NAME);
return GPS_ERR_CLASS;
}
gpsdrv_dev =
device_create(gpsdrv_class, NULL, MKDEV(gpsdrv_major, 0),
NULL, DEVICE_NAME);
if (IS_ERR(gpsdrv_dev)) {
GPSDRV_ERR(" Error in class_create");
unregister_chrdev(gpsdrv_major, DEVICE_NAME);
class_destroy(gpsdrv_class);
return GPS_ERR_CLASS;
}
return GPS_SUCCESS;
}
/** gpsdrv_open Function
* This function will perform an register on ST driver.
*
* Parameters :
* @file : File pointer for GPS char driver
* @inod :
* Returns GPS_SUCCESS - on success
* else suitable error code
*/
int gpsdrv_open(struct inode *inod, struct file *file)
{
int ret = 0;
unsigned long timeout = GPSDRV_REG_TIMEOUT;
struct gpsdrv_data *hgps;
GPSDRV_DBG(" Inside %s", __func__);
/* Allocate local resource memory */
hgps = kzalloc(sizeof(struct gpsdrv_data), GFP_KERNEL);
if (!(hgps)) {
GPSDRV_ERR("Can't allocate GPS data structure");
return -ENOMEM;
}
/* Initialize wait queue, skb queue head and
* registration complete strucuture
*/
skb_queue_head_init(&hgps->rx_list);
skb_queue_head_init(&hgps->tx_list);
init_completion(&hgps->gpsdrv_reg_completed);
init_waitqueue_head(&hgps->gpsdrv_data_q);
spin_lock_init(&hgps->lock);
/* Check if GPS is already registered with ST */
if (test_and_set_bit(GPS_ST_REGISTERED, &hgps->state)) {
GPSDRV_ERR("GPS Registered/Registration in progress with ST"
" ,open called again?");
return -EAGAIN;
}
/* Initialize gpsdrv_reg_completed so as to wait for completion
* on the same
* if st_register returns with a PENDING status
*/
INIT_COMPLETION(hgps->gpsdrv_reg_completed);
gpsdrv_proto.priv_data = hgps;
/* Resgister GPS with ST */
ret = st_register(&gpsdrv_proto);
GPSDRV_VER(" st_register returned %d", ret);
/* If GPS Registration returned with error, then clear GPS_ST_REGISTERED
* for future open calls and return the appropriate error code
*/
if (ret < 0 && ret != -EINPROGRESS) {
GPSDRV_ERR(" st_register failed");
clear_bit(GPS_ST_REGISTERED, &hgps->state);
if (ret == -EINPROGRESS)
return -EAGAIN;
return GPS_ERR_FAILURE;
}
/* if returned status is pending, wait for the completion */
if (ret == -EINPROGRESS) {
GPSDRV_VER(" GPS Register waiting for completion ");
timeout = wait_for_completion_timeout \
(&hgps->gpsdrv_reg_completed, msecs_to_jiffies(timeout));
/* Check for timed out condition */
if (0 == timeout) {
GPSDRV_ERR("st_register failed-GPS Device \
Registration timed out");
clear_bit(GPS_ST_REGISTERED, &hgps->state);
return -ETIMEDOUT;
} else if (0 > hgps->streg_cbdata) {
/* gpsdrv_st_recv Function
* This is Called in from -- ST Core when a data is received
* This is a registered callback with ST core when the gps driver registers
* with ST.
*
* Parameters:
* @skb : SKB buffer pointer which contains the incoming Ch-9 GPS data.
* Returns:
* GPS_SUCCESS - On Success
* else suitable error code
*/
long gpsdrv_st_recv(void *arg, struct sk_buff *skb)
{
struct gpsdrv_event_hdr gpsdrv_hdr = { 0x00, 0x0000 };
struct gpsdrv_data *hgps = (struct gpsdrv_data *)arg;
/* SKB is NULL */
if (NULL == skb) {
GPSDRV_ERR("Input SKB is NULL");
return GPS_ERR_FAILURE;
}
/* Sanity Check - To Check if the Rx Pkt is Channel -9 or not */
if (0x09 != skb->cb[0]) {
GPSDRV_ERR("Input SKB is not a Channel-9 packet");
return GPS_ERR_FAILURE;
}
/* Copy Ch-9 info to local structure */
memcpy(&gpsdrv_hdr, skb->data, GPS_CH9_PKT_HDR_SIZE - 1);
skb_pull(skb, GPS_CH9_PKT_HDR_SIZE - 1);
/* check if skb->len and gpsdrv_hdr.plen are equal */
if (skb->len != gpsdrv_hdr.plen) {
GPSDRV_ERR("Received corrupted packet - Length Mismatch");
return -EINVAL;
}
#ifdef VERBOSE
printk(KERN_INFO"data start >>\n");
print_hex_dump(KERN_INFO, ">in>", DUMP_PREFIX_NONE,
16, 1, skb->data, skb->len, 0);
printk(KERN_INFO"\n<< end\n");
#endif
/* Check the Opcode */
if ((gpsdrv_hdr.opcode != GPS_CH9_OP_READ) && (gpsdrv_hdr.opcode != \
GPS_CH9_OP_COMPLETED_EVT)) {
GPSDRV_ERR("Rec corrupt pkt opcode %x", gpsdrv_hdr.opcode);
return -EINVAL;
}
/* Strip Channel 9 packet information from SKB only
* if the opcode is GPS_CH9_OP_READ and get AI2 packet
*/
if (GPS_CH9_OP_READ == gpsdrv_hdr.opcode) {
spin_lock(&hgps->lock);
skb_queue_tail(&hgps->rx_list, skb);
spin_unlock(&hgps->lock);
wake_up_interruptible(&hgps->gpsdrv_data_q);
} else {
/* Copy Ch-9 info to local structure */
memcpy(&hgps->tx_count, skb->data, 1);
GPSDRV_VER(" Tx count = %x", hgps->tx_count);
/* Check if Tx queue and Tx count not empty */
if ((0 != hgps->tx_count) && \
(!skb_queue_empty(&hgps->tx_list))) {
/* Schedule the Tx-task let */
GPSDRV_VER(" Scheduling tasklet to write");
tasklet_schedule(&hgps->gpsdrv_tx_tsklet);
}
/* Free the received command complete SKB */
kfree_skb(skb);
}
return GPS_SUCCESS;
}
/** gpsdrv_ioctl Function
* This will peform the functions as directed by the command and command
* argument.
*
* Parameters :
* @file : File pointer for GPS char driver
* @cmd : IOCTL Command
* @arg : Command argument for IOCTL command
* Returns GPS_SUCCESS on success
* else suitable error code
*/
static long gpsdrv_ioctl(struct file *file,
unsigned int cmd, unsigned long arg)
{
struct sk_buff *skb = NULL;
int retCode = GPS_SUCCESS;
struct gpsdrv_data *hgps;
GPSDRV_DBG(" Inside %s", __func__);
/* Validate input parameters */
if ((NULL == file) || (0 == cmd)) {
GPSDRV_ERR("Invalid input parameters passed to %s", __func__);
return -EINVAL;
}
hgps = file->private_data;
/* Check if GPS is registered to perform IOCTL operation */
if (!test_bit(GPS_ST_RUNNING, &hgps->state)) {
GPSDRV_ERR("GPS Device is not running");
return -EINVAL;
}
switch (cmd) {
case TCFLSH:
GPSDRV_VER(" IOCTL TCFLSH invoked with %ld argument", arg);
switch (arg) {
/* purge Rx/Tx SKB list queues depending on arg value */
case TCIFLUSH:
skb_queue_purge(&hgps->rx_list);
break;
case TCOFLUSH:
skb_queue_purge(&hgps->tx_list);
break;
case TCIOFLUSH:
skb_queue_purge(&hgps->rx_list);
skb_queue_purge(&hgps->tx_list);
break;
default:
GPSDRV_ERR("Invalid Command passed for tcflush");
retCode = 0;
break;
}
break;
case FIONREAD:
/* Deque the SKB from the head if rx_list is not empty
* And update the argument with skb->len to provide
* the amount of data available in the available SKB
*/
skb = skb_dequeue(&hgps->rx_list);
if (skb != NULL) {
*(unsigned int *)arg = skb->len;
/* Re-Store the SKB for furtur Read operations */
skb_queue_head(&hgps->rx_list, skb);
} else {
*(unsigned int *)arg = 0;
}
GPSDRV_DBG("returning %d\n", *(unsigned int *)arg);
break;
default:
GPSDRV_DBG("Un-Identified IOCTL %d", cmd);
retCode = 0;
break;
}
return retCode;
}
/* gpsdrv_write Function
* This function will pre-pend the GPS-Channel-9 header to the
* incoming AI2 packet sent from the GPS host application.
*
* Parameters :
* @file : File pointer for GPS char driver
* @data : AI2 packet data from GPS application
* @size : Size of the AI2 packet data
* @offset :
* Returns Size of AI2 packet on success
* else suitable error code
*/
ssize_t gpsdrv_write(struct file *file, const char __user *data,
size_t size, loff_t *offset)
{
unsigned char channel = GPS_CH9_PKT_NUMBER; /* GPS Channel number */
/* Initialize gpsdrv_event_hdr with write opcode */
struct gpsdrv_event_hdr gpsdrv_hdr = { GPS_CH9_OP_WRITE, 0x0000 };
struct sk_buff *skb = NULL;
struct gpsdrv_data *hgps;
GPSDRV_DBG(" Inside %s", __func__);
/* Validate input parameters */
if ((NULL == file) || (((NULL == data) || (0 == size)))) {
GPSDRV_ERR("Invalid input params passed to %s", __func__);
return -EINVAL;
}
hgps = file->private_data;
/* Check if GPS is registered to perform write operation */
if (!test_bit(GPS_ST_RUNNING, &hgps->state)) {
GPSDRV_ERR("GPS Device is not running");
return -EINVAL;
}
if (!hgps->st_write) {
GPSDRV_ERR(" Can't write to ST, hgps->st_write null ?");
return -EINVAL;
}
skb = alloc_skb(size + GPS_CH9_PKT_HDR_SIZE, GFP_ATOMIC);
/* Validate Created SKB */
if (NULL == skb) {
GPSDRV_ERR("Error aaloacting SKB");
return -ENOMEM;
}
/* Update chnl-9 information with plen=AI2 pckt size which is "size"*/
gpsdrv_hdr.plen = size;
/* PrePend Channel-9 header to AI2 packet and write to SKB */
memcpy(skb_put(skb, 1), &channel, 1);
memcpy(skb_put(skb, GPS_CH9_PKT_HDR_SIZE - 1), &gpsdrv_hdr,
GPS_CH9_PKT_HDR_SIZE - 1);
/* Forward the data from the user space to ST core */
if (copy_from_user(skb_put(skb, size), data, size)) {
GPSDRV_ERR(" Unable to copy from user space");
kfree_skb(skb);
return GPS_ERR_CPY_FRM_USR;
}
#ifdef VERBOSE
GPSDRV_VER("start data..");
print_hex_dump(KERN_INFO, "<out<", DUMP_PREFIX_NONE,
16, 1, skb->data, size, 0);
GPSDRV_VER("\n..end data");
#endif
/* Check if data can be sent to GPS chip
* If not, add it to queue and that can be sent later
*/
spin_lock(&hgps->lock);
if (0 != hgps->tx_count) {
/* If TX Q is empty send current SKB;
* else, queue current SKB at end of tx_list queue and
* send first SKB in tx_list queue.
*/
hgps->tx_count--;
spin_unlock(&hgps->lock);
GPSDRV_VER(" Tx count in gpsdrv_write = %x", hgps->tx_count);
if (skb_queue_empty(&hgps->tx_list)) {
hgps->st_write(skb);
} else {
skb_queue_tail(&hgps->tx_list, skb);
hgps->st_write(skb_dequeue(&hgps->tx_list));
}
} else {
/* Add it to TX queue */
spin_unlock(&hgps->lock);
GPSDRV_VER(" SKB added to Tx queue ");
GPSDRV_VER("Tx count = %x ", hgps->tx_count);
skb_queue_tail(&hgps->tx_list, skb);
/* This is added for precaution in the case that there is a
* context switch during the execution of the above lines.
* Redundant otherwise.
*/
if ((0 != hgps->tx_count) && \
(!skb_queue_empty(&hgps->tx_list))) {
/* Schedule the Tx-task let */
GPSDRV_VER("Scheduling tasklet to write\n");
tasklet_schedule(&hgps->gpsdrv_tx_tsklet);
}
}
return size;
}
