V4L/DVB (12142): radio-si470x: Add suport for RDS endpoint interrupt mode

Add support for interrupt mode for RDS endpoint, instead of polling.
Improves RDS reception significantly

Signed-off-by: Edouard Lafargue <edouard@lafargue.name>
Acked-by: Tobias Lorenz <tobias.lorenz@gmx.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

1 files changed, 192 insertions, 158 deletions

diff --git a/drivers/media/radio/radio-si470x.c b/drivers/media/radio/radio-si470x.c
index e85f318b4d2b..41f304325074 100644
--- a/drivers/media/radio/radio-si470x.c
+++ b/drivers/media/radio/radio-si470x.c
@@ -106,20 +106,24 @@
  *              Tobias Lorenz <tobias.lorenz@gmx.net>
  *              - add LED status output
  *              - get HW/SW version from scratchpad
+ * 2009-06-16   Edouard Lafargue <edouard@lafargue.name>
+ *              Version 1.0.10
+ *              - add support for interrupt mode for RDS endpoint,
+ *                instead of polling.
+ *                Improves RDS reception significantly
  *
  * ToDo:
  * - add firmware download/update support
- * - RDS support: interrupt mode, instead of polling
  */
 
 
 /* driver definitions */
 #define DRIVER_AUTHOR "Tobias Lorenz <tobias.lorenz@gmx.net>"
 #define DRIVER_NAME "radio-si470x"
-#define DRIVER_KERNEL_VERSION KERNEL_VERSION(1, 0, 9)
+#define DRIVER_KERNEL_VERSION KERNEL_VERSION(1, 0, 10)
 #define DRIVER_CARD "Silicon Labs Si470x FM Radio Receiver"
 #define DRIVER_DESC "USB radio driver for Si470x FM Radio Receivers"
-#define DRIVER_VERSION "1.0.9"
+#define DRIVER_VERSION "1.0.10"
 
 
 /* kernel includes */
@@ -218,16 +222,6 @@ static unsigned short max_rds_errors = 1;
 module_param(max_rds_errors, ushort, 0644);
 MODULE_PARM_DESC(max_rds_errors, "RDS maximum block errors: *1*");
 
-/* RDS poll frequency */
-static unsigned int rds_poll_time = 40;
-/* 40 is used by the original USBRadio.exe */
-/* 50 is used by radio-cadet */
-/* 75 should be okay */
-/* 80 is the usual RDS receive interval */
-module_param(rds_poll_time, uint, 0644);
-MODULE_PARM_DESC(rds_poll_time, "RDS poll time (ms): *40*");
-
-
 
 /**************************************************************************
  * Register Definitions
@@ -450,6 +444,12 @@ struct si470x_device {
         struct usb_interface *intf;
         struct video_device *videodev;
 
+        /* Interrupt endpoint handling */
+        char *int_in_buffer;
+        struct usb_endpoint_descriptor *int_in_endpoint;
+        struct urb *int_in_urb;
+        int int_in_running;
+
         /* driver management */
         unsigned int users;
         unsigned char disconnected;
@@ -459,7 +459,6 @@ struct si470x_device {
         unsigned short registers[RADIO_REGISTER_NUM];
 
         /* RDS receive buffer */
-        struct delayed_work work;
         wait_queue_head_t read_queue;
         struct mutex lock;              /* buffer locking */
         unsigned char *buffer;          /* size is always multiple of three */
@@ -865,43 +864,6 @@ static int si470x_get_all_registers(struct si470x_device *radio)
 
 
 /**************************************************************************
- * General Driver Functions - RDS_REPORT
- **************************************************************************/
-
-/*
- * si470x_get_rds_registers - read rds registers
- */
-static int si470x_get_rds_registers(struct si470x_device *radio)
-{
-        unsigned char buf[RDS_REPORT_SIZE];
-        int retval;
-        int size;
-        unsigned char regnr;
-
-        buf[0] = RDS_REPORT;
-
-        retval = usb_interrupt_msg(radio->usbdev,
-                usb_rcvintpipe(radio->usbdev, 1),
-                (void *) &buf, sizeof(buf), &size, usb_timeout);
-        if (size != sizeof(buf))
-                printk(KERN_WARNING DRIVER_NAME ": si470x_get_rds_registers: "
-                        "return size differs: %d != %zu\n", size, sizeof(buf));
-        if (retval < 0)
-                printk(KERN_WARNING DRIVER_NAME ": si470x_get_rds_registers: "
-                        "usb_interrupt_msg returned %d\n", retval);
-
-        if (retval >= 0)
-                for (regnr = 0; regnr < RDS_REGISTER_NUM; regnr++)
-                        radio->registers[STATUSRSSI + regnr] =
-                                get_unaligned_be16(
-                                &buf[regnr * RADIO_REGISTER_SIZE + 1]);
-
-        return (retval < 0) ? -EINVAL : 0;
-}
-
-
-
-/**************************************************************************
  * General Driver Functions - LED_REPORT
  **************************************************************************/
 
@@ -959,102 +921,118 @@ static int si470x_get_scratch_page_versions(struct si470x_device *radio)
  **************************************************************************/
 
 /*
- * si470x_rds - rds processing function
+ * si470x_int_in_callback - rds callback and processing function
+ *
+ * TODO: do we need to use mutex locks in some sections?
  */
-static void si470x_rds(struct si470x_device *radio)
+static void si470x_int_in_callback(struct urb *urb)
 {
+        struct si470x_device *radio = urb->context;
+        unsigned char buf[RDS_REPORT_SIZE];
+        int retval;
+        unsigned char regnr;
         unsigned char blocknum;
         unsigned short bler; /* rds block errors */
         unsigned short rds;
         unsigned char tmpbuf[3];
 
-        /* get rds blocks */
-        if (si470x_get_rds_registers(radio) < 0)
-                return;
-        if ((radio->registers[STATUSRSSI] & STATUSRSSI_RDSR) == 0) {
-                /* No RDS group ready */
-                return;
-        }
-        if ((radio->registers[STATUSRSSI] & STATUSRSSI_RDSS) == 0) {
-                /* RDS decoder not synchronized */
-                return;
-        }
-
-        /* copy all four RDS blocks to internal buffer */
-        mutex_lock(&radio->lock);
-        for (blocknum = 0; blocknum < 4; blocknum++) {
-                switch (blocknum) {
-                default:
-                        bler = (radio->registers[STATUSRSSI] &
-                                        STATUSRSSI_BLERA) >> 9;
-                        rds = radio->registers[RDSA];
-                        break;
-                case 1:
-                        bler = (radio->registers[READCHAN] &
-                                        READCHAN_BLERB) >> 14;
-                        rds = radio->registers[RDSB];
-                        break;
-                case 2:
-                        bler = (radio->registers[READCHAN] &
-                                        READCHAN_BLERC) >> 12;
-                        rds = radio->registers[RDSC];
-                        break;
-                case 3:
-                        bler = (radio->registers[READCHAN] &
-                                        READCHAN_BLERD) >> 10;
-                        rds = radio->registers[RDSD];
-                        break;
-                };
-
-                /* Fill the V4L2 RDS buffer */
-                put_unaligned_le16(rds, &tmpbuf);
-                tmpbuf[2] = blocknum;           /* offset name */
-                tmpbuf[2] |= blocknum << 3;     /* received offset */
-                if (bler > max_rds_errors)
-                        tmpbuf[2] |= 0x80; /* uncorrectable errors */
-                else if (bler > 0)
-                        tmpbuf[2] |= 0x40; /* corrected error(s) */
-
-                /* copy RDS block to internal buffer */
-                memcpy(&radio->buffer[radio->wr_index], &tmpbuf, 3);
-                radio->wr_index += 3;
-
-                /* wrap write pointer */
-                if (radio->wr_index >= radio->buf_size)
-                        radio->wr_index = 0;
-
-                /* check for overflow */
-                if (radio->wr_index == radio->rd_index) {
-                        /* increment and wrap read pointer */
-                        radio->rd_index += 3;
-                        if (radio->rd_index >= radio->buf_size)
-                                radio->rd_index = 0;
+        if (urb->status) {
+                if (urb->status == -ENOENT ||
+                                urb->status == -ECONNRESET ||
+                                urb->status == -ESHUTDOWN) {
+                        return;
+                } else {
+                        printk(KERN_WARNING DRIVER_NAME
+                         ": non-zero urb status (%d)\n", urb->status);
+                        goto resubmit; /* Maybe we can recover. */
                 }
         }
-        mutex_unlock(&radio->lock);
-
-        /* wake up read queue */
-        if (radio->wr_index != radio->rd_index)
-                wake_up_interruptible(&radio->read_queue);
-}
-
-
-/*
- * si470x_work - rds work function
- */
-static void si470x_work(struct work_struct *work)
-{
-        struct si470x_device *radio = container_of(work, struct si470x_device,
-                work.work);
 
         /* safety checks */
         if (radio->disconnected)
                 return;
         if ((radio->registers[SYSCONFIG1] & SYSCONFIG1_RDS) == 0)
-                return;
+                goto resubmit;
 
-        si470x_rds(radio);
-        schedule_delayed_work(&radio->work, msecs_to_jiffies(rds_poll_time));
+        if (urb->actual_length > 0) {
+                /* Update RDS registers with URB data */
+                buf[0] = RDS_REPORT;
+                for (regnr = 0; regnr < RDS_REGISTER_NUM; regnr++)
+                        radio->registers[STATUSRSSI + regnr] =
+                            get_unaligned_be16(&radio->int_in_buffer[
+                                regnr * RADIO_REGISTER_SIZE + 1]);
+                /* get rds blocks */
+                if ((radio->registers[STATUSRSSI] & STATUSRSSI_RDSR) == 0) {
+                        /* No RDS group ready, better luck next time */
+                        goto resubmit;
+                }
+                if ((radio->registers[STATUSRSSI] & STATUSRSSI_RDSS) == 0) {
+                        /* RDS decoder not synchronized */
+                        goto resubmit;
+                }
+                for (blocknum = 0; blocknum < 4; blocknum++) {
+                        switch (blocknum) {
+                        default:
+                                bler = (radio->registers[STATUSRSSI] &
+                                                STATUSRSSI_BLERA) >> 9;
+                                rds = radio->registers[RDSA];
+                                break;
+                        case 1:
+                                bler = (radio->registers[READCHAN] &
+                                                READCHAN_BLERB) >> 14;
+                                rds = radio->registers[RDSB];
+                                break;
+                        case 2:
+                                bler = (radio->registers[READCHAN] &
+                                                READCHAN_BLERC) >> 12;
+                                rds = radio->registers[RDSC];
+                                break;
+                        case 3:
+                                bler = (radio->registers[READCHAN] &
+                                                READCHAN_BLERD) >> 10;
+                                rds = radio->registers[RDSD];
+                                break;
+                        };
+
+                        /* Fill the V4L2 RDS buffer */
+                        put_unaligned_le16(rds, &tmpbuf);
+                        tmpbuf[2] = blocknum;           /* offset name */
+                        tmpbuf[2] |= blocknum << 3;     /* received offset */
+                        if (bler > max_rds_errors)
+                                tmpbuf[2] |= 0x80; /* uncorrectable errors */
+                        else if (bler > 0)
+                                tmpbuf[2] |= 0x40; /* corrected error(s) */
+
+                        /* copy RDS block to internal buffer */
+                        memcpy(&radio->buffer[radio->wr_index], &tmpbuf, 3);
+                        radio->wr_index += 3;
+
+                        /* wrap write pointer */
+                        if (radio->wr_index >= radio->buf_size)
+                                radio->wr_index = 0;
+
+                        /* check for overflow */
+                        if (radio->wr_index == radio->rd_index) {
+                                /* increment and wrap read pointer */
+                                radio->rd_index += 3;
+                                if (radio->rd_index >= radio->buf_size)
+                                        radio->rd_index = 0;
+                        }
+                }
+                if (radio->wr_index != radio->rd_index)
+                        wake_up_interruptible(&radio->read_queue);
+        }
+
+resubmit:
+        /* Resubmit if we're still running. */
+        if (radio->int_in_running && radio->usbdev) {
+                retval = usb_submit_urb(radio->int_in_urb, GFP_ATOMIC);
+                if (retval) {
+                        printk(KERN_WARNING DRIVER_NAME
+                               ": resubmitting urb failed (%d)", retval);
+                        radio->int_in_running = 0;
+                }
+        }
 }
 
 
@@ -1076,8 +1054,6 @@ static ssize_t si470x_fops_read(struct file *file, char __user *buf,
         /* switch on rds reception */
         if ((radio->registers[SYSCONFIG1] & SYSCONFIG1_RDS) == 0) {
                 si470x_rds_on(radio);
-                schedule_delayed_work(&radio->work,
-                        msecs_to_jiffies(rds_poll_time));
         }
 
         /* block if no new data available */
@@ -1136,8 +1112,6 @@ static unsigned int si470x_fops_poll(struct file *file,
         /* switch on rds reception */
         if ((radio->registers[SYSCONFIG1] & SYSCONFIG1_RDS) == 0) {
                 si470x_rds_on(radio);
-                schedule_delayed_work(&radio->work,
-                        msecs_to_jiffies(rds_poll_time));
         }
 
         poll_wait(file, &radio->read_queue, pts);
@@ -1167,11 +1141,37 @@ static int si470x_fops_open(struct file *file)
                 goto done;
         }
 
+        printk(KERN_INFO DRIVER_NAME
+                 ": Opened radio (users now: %i)\n", radio->users);
+
         if (radio->users == 1) {
                 /* start radio */
                 retval = si470x_start(radio);
-                if (retval < 0)
+                if (retval < 0) {
                         usb_autopm_put_interface(radio->intf);
+                        goto done;
+                }
+                /* Initialize interrupt URB. */
+                usb_fill_int_urb(radio->int_in_urb, radio->usbdev,
+                        usb_rcvintpipe(radio->usbdev,
+                        radio->int_in_endpoint->bEndpointAddress),
+                        radio->int_in_buffer,
+                        le16_to_cpu(radio->int_in_endpoint->wMaxPacketSize),
+                        si470x_int_in_callback,
+                        radio,
+                        radio->int_in_endpoint->bInterval);
+
+                radio->int_in_running = 1;
+                mb();
+
+                retval = usb_submit_urb(radio->int_in_urb, GFP_KERNEL);
+                if (retval) {
+                        printk(KERN_INFO DRIVER_NAME
+                                 ": submitting int urb failed (%d)\n", retval);
+                        radio->int_in_running = 0;
+                        usb_autopm_put_interface(radio->intf);
+                }
+
         }
 
 done:
@@ -1196,17 +1196,25 @@ static int si470x_fops_release(struct file *file)
 
         mutex_lock(&radio->disconnect_lock);
         radio->users--;
+        printk(KERN_INFO DRIVER_NAME
+                 ": Closed radio (remaining users:%i)\n", radio->users);
         if (radio->users == 0) {
+
+                /* Shutdown Interrupt handler */
+                if (radio->int_in_running) {
+                        radio->int_in_running = 0;
+                if (radio->int_in_urb)
+                        usb_kill_urb(radio->int_in_urb);
+                }
+
                 if (radio->disconnected) {
                         video_unregister_device(radio->videodev);
+                        kfree(radio->int_in_buffer);
                         kfree(radio->buffer);
                         kfree(radio);
                         goto unlock;
                 }
 
-                /* stop rds reception */
-                cancel_delayed_work_sync(&radio->work);
-
                 /* cancel read processes */
                 wake_up_interruptible(&radio->read_queue);
 
@@ -1657,7 +1665,9 @@ static int si470x_usb_driver_probe(struct usb_interface *intf,
                 const struct usb_device_id *id)
 {
         struct si470x_device *radio;
-        int retval = 0;
+        struct usb_host_interface *iface_desc;
+        struct usb_endpoint_descriptor *endpoint;
+        int i, int_end_size, retval = 0;
 
         /* private data allocation and initialization */
         radio = kzalloc(sizeof(struct si470x_device), GFP_KERNEL);
@@ -1672,11 +1682,45 @@ static int si470x_usb_driver_probe(struct usb_interface *intf,
         mutex_init(&radio->disconnect_lock);
         mutex_init(&radio->lock);
 
+        iface_desc = intf->cur_altsetting;
+
+        /* Set up interrupt endpoint information. */
+        for (i = 0; i < iface_desc->desc.bNumEndpoints; ++i) {
+                endpoint = &iface_desc->endpoint[i].desc;
+                if (((endpoint->bEndpointAddress & USB_ENDPOINT_DIR_MASK) ==
+                 USB_DIR_IN) && ((endpoint->bmAttributes &
+                 USB_ENDPOINT_XFERTYPE_MASK) == USB_ENDPOINT_XFER_INT))
+                        radio->int_in_endpoint = endpoint;
+        }
+        if (!radio->int_in_endpoint) {
+                printk(KERN_INFO DRIVER_NAME
+                        ": could not find interrupt in endpoint\n");
+                retval = -EIO;
+                goto err_radio;
+        }
+
+        int_end_size = le16_to_cpu(radio->int_in_endpoint->wMaxPacketSize);
+
+        radio->int_in_buffer = kmalloc(int_end_size, GFP_KERNEL);
+        if (!radio->int_in_buffer) {
+                printk(KERN_INFO DRIVER_NAME
+                        "could not allocate int_in_buffer");
+                retval = -ENOMEM;
+                goto err_radio;
+        }
+
+        radio->int_in_urb = usb_alloc_urb(0, GFP_KERNEL);
+        if (!radio->int_in_urb) {
+                printk(KERN_INFO DRIVER_NAME "could not allocate int_in_urb");
+                retval = -ENOMEM;
+                goto err_intbuffer;
+        }
+
         /* video device allocation and initialization */
         radio->videodev = video_device_alloc();
         if (!radio->videodev) {
                 retval = -ENOMEM;
-                goto err_radio;
+                goto err_intbuffer;
         }
         memcpy(radio->videodev, &si470x_viddev_template,
                         sizeof(si470x_viddev_template));
@@ -1734,9 +1778,6 @@ static int si470x_usb_driver_probe(struct usb_interface *intf,
         radio->rd_index = 0;
         init_waitqueue_head(&radio->read_queue);
 
-        /* prepare rds work function */
-        INIT_DELAYED_WORK(&radio->work, si470x_work);
-
         /* register video device */
         retval = video_register_device(radio->videodev, VFL_TYPE_RADIO, radio_nr);
         if (retval) {
@@ -1751,6 +1792,8 @@ err_all:
         kfree(radio->buffer);
 err_video:
         video_device_release(radio->videodev);
+err_intbuffer:
+        kfree(radio->int_in_buffer);
 err_radio:
         kfree(radio);
 err_initial:
@@ -1764,12 +1807,8 @@ err_initial:
 static int si470x_usb_driver_suspend(struct usb_interface *intf,
                 pm_message_t message)
 {
-        struct si470x_device *radio = usb_get_intfdata(intf);
-
         printk(KERN_INFO DRIVER_NAME ": suspending now...\n");
 
-        cancel_delayed_work_sync(&radio->work);
-
         return 0;
 }
 
@@ -1779,16 +1818,8 @@ static int si470x_usb_driver_suspend(struct usb_interface *intf,
  */
 static int si470x_usb_driver_resume(struct usb_interface *intf)
 {
-        struct si470x_device *radio = usb_get_intfdata(intf);
-
         printk(KERN_INFO DRIVER_NAME ": resuming now...\n");
 
-        mutex_lock(&radio->lock);
-        if (radio->users && radio->registers[SYSCONFIG1] & SYSCONFIG1_RDS)
-                schedule_delayed_work(&radio->work,
-                        msecs_to_jiffies(rds_poll_time));
-        mutex_unlock(&radio->lock);
-
         return 0;
 }
 
@@ -1802,12 +1833,15 @@ static void si470x_usb_driver_disconnect(struct usb_interface *intf)
 
         mutex_lock(&radio->disconnect_lock);
         radio->disconnected = 1;
-        cancel_delayed_work_sync(&radio->work);
         usb_set_intfdata(intf, NULL);
         if (radio->users == 0) {
                 /* set led to disconnect state */
                 si470x_set_led_state(radio, BLINK_ORANGE_LED);
 
+                /* Free data structures. */
+                usb_free_urb(radio->int_in_urb);
+
+                kfree(radio->int_in_buffer);
                 video_unregister_device(radio->videodev);
                 kfree(radio->buffer);
                 kfree(radio);