[media] xc4000: added mutex

This patch adds a mutex to xc4000_priv, to protect the driver
from being accessed by multiple processes at the same time.

Signed-off-by: Istvan Varga <istvan_v@mailbox.hu>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

1 files changed, 50 insertions, 30 deletions

diff --git a/drivers/media/common/tuners/xc4000.c b/drivers/media/common/tuners/xc4000.c
index 307a8745e06e..be43a6dfac6c 100644
--- a/drivers/media/common/tuners/xc4000.c
+++ b/drivers/media/common/tuners/xc4000.c
@@ -28,6 +28,7 @@
 #include <linux/delay.h>
 #include <linux/dvb/frontend.h>
 #include <linux/i2c.h>
+#include <linux/mutex.h>
 #include <asm/unaligned.h>
 
 #include "dvb_frontend.h"
@@ -90,6 +91,7 @@ struct xc4000_priv {
         struct firmware_properties cur_fw;
         __u16   hwmodel;
         __u16   hwvers;
+        struct mutex    lock;
 };
 
 /* Misc Defines */
@@ -1145,10 +1147,12 @@ static int xc4000_set_params(struct dvb_frontend *fe,
 {
         struct xc4000_priv *priv = fe->tuner_priv;
         unsigned int type;
-        int     ret;
+        int     ret = -EREMOTEIO;
 
         dprintk(1, "%s() frequency=%d (Hz)\n", __func__, params->frequency);
 
+        mutex_lock(&priv->lock);
+
         if (fe->ops.info.type == FE_ATSC) {
                 dprintk(1, "%s() ATSC\n", __func__);
                 switch (params->u.vsb.modulation) {
@@ -1172,7 +1176,8 @@ static int xc4000_set_params(struct dvb_frontend *fe,
                         type = DTV6;
                         break;
                 default:
-                        return -EINVAL;
+                        ret = -EINVAL;
+                        goto fail;
                 }
         } else if (fe->ops.info.type == FE_OFDM) {
                 dprintk(1, "%s() OFDM\n", __func__);
@@ -1208,28 +1213,29 @@ static int xc4000_set_params(struct dvb_frontend *fe,
                         break;
                 default:
                         printk(KERN_ERR "xc4000 bandwidth not set!\n");
-                        return -EINVAL;
+                        ret = -EINVAL;
+                        goto fail;
                 }
                 priv->rf_mode = XC_RF_MODE_AIR;
         } else {
                 printk(KERN_ERR "xc4000 modulation type not supported!\n");
-                return -EINVAL;
+                ret = -EINVAL;
+                goto fail;
         }
 
         dprintk(1, "%s() frequency=%d (compensated)\n",
                 __func__, priv->freq_hz);
 
         /* Make sure the correct firmware type is loaded */
-        if (check_firmware(fe, type, 0, priv->if_khz) != XC_RESULT_SUCCESS) {
-                return -EREMOTEIO;
-        }
+        if (check_firmware(fe, type, 0, priv->if_khz) != XC_RESULT_SUCCESS)
+                goto fail;
 
         ret = xc_SetSignalSource(priv, priv->rf_mode);
         if (ret != XC_RESULT_SUCCESS) {
                 printk(KERN_ERR
-                        "xc4000: xc_SetSignalSource(%d) failed\n",
-                        priv->rf_mode);
-                return -EREMOTEIO;
+                       "xc4000: xc_SetSignalSource(%d) failed\n",
+                       priv->rf_mode);
+                goto fail;
         }
 
         ret = xc_SetTVStandard(priv,
@@ -1237,33 +1243,32 @@ static int xc4000_set_params(struct dvb_frontend *fe,
                 XC4000_Standard[priv->video_standard].AudioMode);
         if (ret != XC_RESULT_SUCCESS) {
                 printk(KERN_ERR "xc4000: xc_SetTVStandard failed\n");
-                return -EREMOTEIO;
-        }
-#ifdef DJH_DEBUG
-        ret = xc_set_IF_frequency(priv, priv->if_khz);
-        if (ret != XC_RESULT_SUCCESS) {
-                printk(KERN_ERR "xc4000: xc_Set_IF_frequency(%d) failed\n",
-                       priv->if_khz);
-                return -EIO;
+                goto fail;
         }
-#endif
         xc_tune_channel(priv, priv->freq_hz, XC_TUNE_DIGITAL);
 
         if (debug)
                 xc_debug_dump(priv);
 
-        return 0;
+        ret = 0;
+
+fail:
+        mutex_unlock(&priv->lock);
+
+        return ret;
 }
 
 static int xc4000_set_analog_params(struct dvb_frontend *fe,
         struct analog_parameters *params)
 {
         struct xc4000_priv *priv = fe->tuner_priv;
-        int     ret;
+        int     ret = -EREMOTEIO;
 
         dprintk(1, "%s() frequency=%d (in units of 62.5khz)\n",
                 __func__, params->frequency);
 
+        mutex_lock(&priv->lock);
+
         /* Fix me: it could be air. */
         priv->rf_mode = params->mode;
         if (params->mode > XC_RF_MODE_CABLE)
@@ -1318,16 +1323,15 @@ static int xc4000_set_analog_params(struct dvb_frontend *fe,
 tune_channel:
 
         /* FIXME - firmware type not being set properly */
-        if (check_firmware(fe, DTV8, 0, priv->if_khz) != XC_RESULT_SUCCESS) {
-                return -EREMOTEIO;
-        }
+        if (check_firmware(fe, DTV8, 0, priv->if_khz) != XC_RESULT_SUCCESS)
+                goto fail;
 
         ret = xc_SetSignalSource(priv, priv->rf_mode);
         if (ret != XC_RESULT_SUCCESS) {
                 printk(KERN_ERR
-                        "xc4000: xc_SetSignalSource(%d) failed\n",
-                        priv->rf_mode);
-                return -EREMOTEIO;
+                       "xc4000: xc_SetSignalSource(%d) failed\n",
+                       priv->rf_mode);
+                goto fail;
         }
 
         ret = xc_SetTVStandard(priv,
@@ -1335,7 +1339,7 @@ tune_channel:
                 XC4000_Standard[priv->video_standard].AudioMode);
         if (ret != XC_RESULT_SUCCESS) {
                 printk(KERN_ERR "xc4000: xc_SetTVStandard failed\n");
-                return -EREMOTEIO;
+                goto fail;
         }
 
         xc_tune_channel(priv, priv->freq_hz, XC_TUNE_ANALOG);
@@ -1343,7 +1347,12 @@ tune_channel:
         if (debug)
                 xc_debug_dump(priv);
 
-        return 0;
+        ret = 0;
+
+fail:
+        mutex_unlock(&priv->lock);
+
+        return ret;
 }
 
 static int xc4000_get_frequency(struct dvb_frontend *fe, u32 *freq)
@@ -1368,8 +1377,12 @@ static int xc4000_get_status(struct dvb_frontend *fe, u32 *status)
         struct xc4000_priv *priv = fe->tuner_priv;
         u16     lock_status = 0;
 
+        mutex_lock(&priv->lock);
+
         xc_get_lock_status(priv, &lock_status);
 
+        mutex_unlock(&priv->lock);
+
         dprintk(1, "%s() lock_status = 0x%08x\n", __func__, lock_status);
 
         *status = lock_status;
@@ -1386,9 +1399,13 @@ static int xc4000_sleep(struct dvb_frontend *fe)
 static int xc4000_init(struct dvb_frontend *fe)
 {
         struct xc4000_priv *priv = fe->tuner_priv;
+        int     ret;
         dprintk(1, "%s()\n", __func__);
 
-        if (check_firmware(fe, DTV8, 0, priv->if_khz) != XC_RESULT_SUCCESS) {
+        mutex_lock(&priv->lock);
+        ret = check_firmware(fe, DTV8, 0, priv->if_khz);
+        mutex_unlock(&priv->lock);
+        if (ret != XC_RESULT_SUCCESS) {
                 printk(KERN_ERR "xc4000: Unable to initialise tuner\n");
                 return -EREMOTEIO;
         }
@@ -1460,6 +1477,7 @@ struct dvb_frontend *xc4000_attach(struct dvb_frontend *fe,
         case 1:
                 /* new tuner instance */
                 priv->bandwidth = BANDWIDTH_6_MHZ;
+                mutex_init(&priv->lock);
                 fe->tuner_priv = priv;
                 break;
         default:
@@ -1511,7 +1529,9 @@ struct dvb_frontend *xc4000_attach(struct dvb_frontend *fe,
 
         /* FIXME: For now, load the firmware at startup.  We will remove this
            before the code goes to production... */
+        mutex_lock(&priv->lock);
         check_firmware(fe, DTV8, 0, priv->if_khz);
+        mutex_unlock(&priv->lock);
 
         return fe;
 fail: