Fix for aston CAM read timeout problems

2 files changed, 64 insertions, 71 deletions

diff --git a/linux/drivers/media/dvb/dvb-core/dvb_ca_en50221.c b/linux/drivers/media/dvb/dvb-core/dvb_ca_en50221.c
index 106e4ab87..899c2495a 100644
--- a/linux/drivers/media/dvb/dvb-core/dvb_ca_en50221.c
+++ b/linux/drivers/media/dvb/dvb-core/dvb_ca_en50221.c
@@ -34,7 +34,7 @@
 #include <linux/module.h>
 #include <linux/vmalloc.h>
 #include <linux/delay.h>
-#include <asm/semaphore.h>
+#include <asm/rwsem.h>
 #include <asm/atomic.h>
 
 #include "dvb_ca_en50221.h"
@@ -108,7 +108,7 @@ struct dvb_ca_slot {
         int link_buf_size;
 
         /* semaphore for syncing access to slot structure */
-        struct semaphore sem;
+        struct rw_semaphore sem;
 
         /* buffer for incoming packets */
         struct dvb_ringbuffer rx_buffer;
@@ -199,7 +199,6 @@ static u8* findstr(u8* haystack, int hlen, u8* needle, int nlen)
 static int dvb_ca_en50221_check_camstatus(struct dvb_ca_private* ca, int slot)
 {
         int slot_status;
-        int status;
         int cam_present_now;
         int cam_changed;
 
@@ -209,9 +208,7 @@ static int dvb_ca_en50221_check_camstatus(struct dvb_ca_private* ca, int slot)
         }
 
         /* poll mode */
-        if ((status = down_interruptible(&ca->slot_info[slot].sem)) != 0) return status;
         slot_status = ca->pub->poll_slot_status(ca->pub, slot);
-        up(&ca->slot_info[slot].sem);
 
         cam_present_now = (slot_status & DVB_CA_EN50221_POLL_CAM_PRESENT) ? 1: 0;
         cam_changed = (slot_status & DVB_CA_EN50221_POLL_CAM_CHANGED) ? 1: 0;
@@ -550,30 +547,27 @@ static int dvb_ca_en50221_read_data(struct dvb_ca_private* ca, int slot, u8* ebu
 
         dprintk ("%s\n", __FUNCTION__);
 
-        /* acquire the slot */
-        if ((status = down_interruptible(&ca->slot_info[slot].sem)) != 0) return status;
-
         /* check if we have space for a link buf in the rx_buffer */
         if (ebuf == NULL) {
-                if (dvb_ringbuffer_free(&ca->slot_info[slot].rx_buffer) <
-                    (ca->slot_info[slot].link_buf_size + DVB_RINGBUFFER_PKTHDRSIZE)) {
-                        status = -EAGAIN;
-                        goto exit;
+		int buf_free;
+		
+		down_read(&ca->slot_info[slot].sem);
+		buf_free = dvb_ringbuffer_free(&ca->slot_info[slot].rx_buffer);
+		up_read(&ca->slot_info[slot].sem);
+		
+                if (buf_free < (ca->slot_info[slot].link_buf_size + DVB_RINGBUFFER_PKTHDRSIZE)) {
+			status = -EAGAIN;
+			goto exit;
                 }
         }
 
-        /* reset the interface if there's been a tx error */
+        /* check if there is data available */
         if ((status = ca->pub->read_cam_control(ca->pub, slot, CTRLIF_STATUS)) < 0) goto exit;
-        if (status & STATUSREG_TXERR) {
-                ca->slot_info[slot].slot_state = DVB_CA_SLOTSTATE_LINKINIT;
-                status = -EIO;
-                goto exit;
-        }
         if (!(status & STATUSREG_DA)) {
-                /* no data */
-                status = 0;
-                goto exit;
-        }
+		/* no data */
+		status = 0;
+		goto exit;
+	}
 
         /* read the amount of data */
         if ((status = ca->pub->read_cam_control(ca->pub, slot, CTRLIF_SIZE_HIGH)) < 0) goto exit;
@@ -587,19 +581,19 @@ static int dvb_ca_en50221_read_data(struct dvb_ca_private* ca, int slot, u8* ebu
                         printk("dvb_ca: CAM tried to send a buffer larger than the link buffer size!\n");
                         ca->slot_info[slot].slot_state = DVB_CA_SLOTSTATE_LINKINIT;
                         status = -EIO;
-                        goto exit;
+			goto exit;
                 }
                 if (bytes_read < 2) {
                         printk("dvb_ca: CAM sent a buffer that was less than 2 bytes!\n");
                         ca->slot_info[slot].slot_state = DVB_CA_SLOTSTATE_LINKINIT;
                         status = -EIO;
-                        goto exit;
+			goto exit;
                 }
         } else {
                 if (bytes_read > ecount) {
                         printk("dvb_ca: CAM tried to send a buffer larger than the ecount size!\n");
                         status = -EIO;
-                        goto exit;
+			goto exit;
                 }
         }
 
@@ -612,29 +606,32 @@ static int dvb_ca_en50221_read_data(struct dvb_ca_private* ca, int slot, u8* ebu
                 buf[i] = status;
         }
 
-        /* check for read error (RE should now go to 0) */
+        /* check for read error (RE should now be 0) */
         if ((status = ca->pub->read_cam_control(ca->pub, slot, CTRLIF_STATUS)) < 0) goto exit;
         if (status & STATUSREG_RE) {
-                status = -EIO;
-                goto exit;
-        }
+		ca->slot_info[slot].slot_state = DVB_CA_SLOTSTATE_LINKINIT;
+		status = -EIO;
+		goto exit;
+	}
 
-        /* OK, add it to the receive buffer, or copy into external buffer if supplied */
+        /* OK, add it to the receive buffer, or copy into external buffer if supplied */	
         if (ebuf == NULL) {
+		down_read(&ca->slot_info[slot].sem);
                 dvb_ringbuffer_pkt_write(&ca->slot_info[slot].rx_buffer, buf, bytes_read, 0);
+		up_read(&ca->slot_info[slot].sem);
         } else {
                 memcpy(ebuf, buf, bytes_read);
         }
+	
+	dprintk("Received CA packet for slot %i connection id 0x%x last_frag:%i size:0x%x\n", slot, buf[0], (buf[1] & 0x80) == 0, bytes_read);
 
         /* wake up readers when a last_fragment is received */
         if ((buf[1] & 0x80) == 0x00) {
-                wake_up_interruptible(&ca->wait_queue);
+		wake_up_interruptible(&ca->wait_queue);
         }
-
-        status = bytes_read;
+	status = bytes_read;
 
 exit:
-        up(&ca->slot_info[slot].sem);
         return status;
 }
 
@@ -662,22 +659,12 @@ static int dvb_ca_en50221_write_data(struct dvb_ca_private* ca, int slot, u8* bu
         // sanity check
         if (bytes_write > ca->slot_info[slot].link_buf_size) return -EINVAL;
 
-        /* acquire the slot */
-        if ((status = down_interruptible(&ca->slot_info[slot].sem)) != 0) return status;
-
-        /* reset the interface if there's been a tx error */
+        /* check if interface is actually waiting for us to read from it, or if a read is in progress */
         if ((status = ca->pub->read_cam_control(ca->pub, slot, CTRLIF_STATUS)) < 0) goto exitnowrite;
-        if (status & STATUSREG_TXERR) {
-                ca->slot_info[slot].slot_state = DVB_CA_SLOTSTATE_LINKINIT;
-                status = -EIO;
-                goto exitnowrite;
-        }
-
-        /* check if interface is actually waiting for us to read from it */
-        if (status & STATUSREG_DA) {
-                status = -EAGAIN;
-                goto exitnowrite;
-        }
+        if (status & (STATUSREG_DA|STATUSREG_RE)) {
+		status = -EAGAIN;
+		goto exitnowrite;
+	}
 
         /* OK, set HC bit */
         if ((status = ca->pub->write_cam_control(ca->pub, slot, CTRLIF_COMMAND, IRQEN | CMDREG_HC)) != 0) goto exit;
@@ -685,10 +672,10 @@ static int dvb_ca_en50221_write_data(struct dvb_ca_private* ca, int slot, u8* bu
         /* check if interface is still free */
         if ((status = ca->pub->read_cam_control(ca->pub, slot, CTRLIF_STATUS)) < 0) goto exit;
         if (!(status & STATUSREG_FR)) {
-                /* it wasn't free => try again later */
-                status = -EAGAIN;
-                goto exit;
-        }
+		/* it wasn't free => try again later */
+		status = -EAGAIN; 
+		goto exit;
+	}
 
         /* send the amount of data */
         if ((status = ca->pub->write_cam_control(ca->pub, slot, CTRLIF_SIZE_HIGH, bytes_write >> 8)) != 0) goto exit;
@@ -702,16 +689,18 @@ static int dvb_ca_en50221_write_data(struct dvb_ca_private* ca, int slot, u8* bu
         /* check for write error (WE should now be 0) */
         if ((status = ca->pub->read_cam_control(ca->pub, slot, CTRLIF_STATUS)) < 0) goto exit;
         if (status & STATUSREG_WE) {
-                status = -EIO;
-                goto exit;
-        }
+		ca->slot_info[slot].slot_state = DVB_CA_SLOTSTATE_LINKINIT;
+		status = -EIO;
+		goto exit;
+	}
         status = bytes_write;
 
+	dprintk("Wrote CA packet for slot %i, connection id 0x%x last_frag:%i size:0x%x\n", slot, buf[0], (buf[1] & 0x80) == 0, bytes_write);
+	
 exit:
         ca->pub->write_cam_control(ca->pub, slot, CTRLIF_COMMAND, IRQEN);
 
 exitnowrite:
-        up(&ca->slot_info[slot].sem);
         return status;
 }
 
@@ -729,16 +718,14 @@ exitnowrite:
  */
 static int dvb_ca_en50221_slot_shutdown(struct dvb_ca_private* ca, int slot)
 {
-        int status;
-
         dprintk ("%s\n", __FUNCTION__);
 
-        if ((status = down_interruptible(&ca->slot_info[slot].sem)) != 0) return status;
+        down_write(&ca->slot_info[slot].sem);
         ca->pub->slot_shutdown(ca->pub, slot);
         ca->slot_info[slot].slot_state = DVB_CA_SLOTSTATE_NONE;
         if (ca->slot_info[slot].rx_buffer.data) vfree(ca->slot_info[slot].rx_buffer.data);
         ca->slot_info[slot].rx_buffer.data = NULL;
-        up(&ca->slot_info[slot].sem);
+        up_write(&ca->slot_info[slot].sem);
 
         /* need to wake up all processes to check if they're now
            trying to write to a defunct CAM */
@@ -821,10 +808,7 @@ void dvb_ca_en50221_frda_irq(struct dvb_ca_en50221* pubca, int slot)
                 break;
 
         case DVB_CA_SLOTSTATE_RUNNING:
-                flags = ca->pub->read_cam_control(pubca, slot, CTRLIF_STATUS);
-                if (flags & STATUSREG_DA) {
-                        dvb_ca_en50221_thread_wakeup(ca);
-                }
+		if (ca->open) dvb_ca_en50221_read_data(ca, slot, NULL, 0);
                 break;
         }
 }
@@ -1053,7 +1037,11 @@ static int dvb_ca_en50221_thread(void* data)
 
                         case DVB_CA_SLOTSTATE_RUNNING:
                                 if (!ca->open) break;
+				
+				// no need to poll if the CAM supports IRQs
+				if (ca->slot_info[slot].da_irq_supported) break;
 
+				// poll mode
                                 pktcount = 0;
                                 while(dvb_ca_en50221_read_data(ca, slot, NULL, 0) > 0) {
                                         if (!ca->open) break;
@@ -1266,7 +1254,7 @@ static int dvb_ca_en50221_io_read_condition(struct dvb_ca_private* ca, int* resu
         while((slot_count < ca->slot_count) && (!found)) {
                 if (ca->slot_info[slot].slot_state != DVB_CA_SLOTSTATE_RUNNING) goto nextslot;
 
-                if ((*result = down_interruptible(&ca->slot_info[slot].sem)) != 0) return 1;
+                down_read(&ca->slot_info[slot].sem);
 
                 idx = dvb_ringbuffer_pkt_next(&ca->slot_info[slot].rx_buffer, -1, &fraglen);
                 while(idx != -1) {
@@ -1281,7 +1269,7 @@ static int dvb_ca_en50221_io_read_condition(struct dvb_ca_private* ca, int* resu
                         idx = dvb_ringbuffer_pkt_next(&ca->slot_info[slot].rx_buffer, idx, &fraglen);
                 }
 
-                if (!found) up(&ca->slot_info[slot].sem);
+                if (!found) up_read(&ca->slot_info[slot].sem);
 
 nextslot:
                 slot = (slot + 1) % ca->slot_count;
@@ -1378,7 +1366,7 @@ static ssize_t dvb_ca_en50221_io_read(struct file *file, char *buf, size_t count
         status = pktlen;
 
 exit:
-        up(&ca->slot_info[slot].sem);
+        up_read(&ca->slot_info[slot].sem);
         return status;
 }
 
@@ -1406,7 +1394,9 @@ static int dvb_ca_en50221_io_open(struct inode *inode, struct file *file)
 
         for(i=0; i< ca->slot_count; i++) {
                 if (ca->slot_info[i].slot_state == DVB_CA_SLOTSTATE_RUNNING) {
+		        down_write(&ca->slot_info[i].sem);
                         dvb_ringbuffer_flush(&ca->slot_info[i].rx_buffer);
+		        up_write(&ca->slot_info[i].sem);
                 }
         }
 
@@ -1464,7 +1454,7 @@ static unsigned int dvb_ca_en50221_io_poll(struct file *file, poll_table *wait)
         dprintk ("%s\n", __FUNCTION__);
 
         if (dvb_ca_en50221_io_read_condition(ca, &result, &slot) == 1) {
-                up(&ca->slot_info[slot].sem);
+                up_read(&ca->slot_info[slot].sem);
                 mask |= POLLIN;
         }
 
@@ -1475,7 +1465,7 @@ static unsigned int dvb_ca_en50221_io_poll(struct file *file, poll_table *wait)
         poll_wait(file, &ca->wait_queue, wait);
 
         if (dvb_ca_en50221_io_read_condition(ca, &result, &slot) == 1) {
-                up(&ca->slot_info[slot].sem);
+                up_read(&ca->slot_info[slot].sem);
                 mask |= POLLIN;
         }
 
@@ -1559,7 +1549,7 @@ int dvb_ca_en50221_init(struct dvb_adapter *dvb_adapter, struct dvb_ca_en50221*
                 ca->slot_info[i].slot_state = DVB_CA_SLOTSTATE_NONE;
                 atomic_set(&ca->slot_info[i].camchange_count, 0);
                 ca->slot_info[i].camchange_type = DVB_CA_EN50221_CAMCHANGE_REMOVED;
-                init_MUTEX(&ca->slot_info[i].sem);
+                init_rwsem(&ca->slot_info[i].sem);
         }
 
         if (signal_pending(current)) {
diff --git a/linux/drivers/media/dvb/dvb-core/dvb_ca_en50221.h b/linux/drivers/media/dvb/dvb-core/dvb_ca_en50221.h
index 8458f7afd..882ca41a2 100644
--- a/linux/drivers/media/dvb/dvb-core/dvb_ca_en50221.h
+++ b/linux/drivers/media/dvb/dvb-core/dvb_ca_en50221.h
@@ -42,6 +42,9 @@
 /* Structure describing a CA interface */
 struct dvb_ca_en50221 {
 
+	/* NOTE: the read_*, write_* and poll_slot_status functions must use locks as
+	 * they may be called from several threads at once */
+
 	/* functions for accessing attribute memory on the CAM */
 	int (*read_attribute_mem)(struct dvb_ca_en50221* ca, int slot, int address);
 	int (*write_attribute_mem)(struct dvb_ca_en50221* ca, int slot, int address, u8 value);