[media] dvb-frontend: split set_delivery_system()

This function is complex, and has different workflows, one for
DVBv3 calls, and another one for DVBv5 calls. Break it into 3
functions, in order to make easier to understand what each
block does.
No functional changes so far. A few comments got improved.

Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

diff --git a/drivers/media/dvb-core/dvb_frontend.c b/drivers/media/dvb-core/dvb_frontend.c
index 6e50a75..d0d193d 100644 (file)
--- a/drivers/media/dvb-core/dvb_frontend.c
+++ b/drivers/media/dvb-core/dvb_frontend.c
@@ -1509,132 +1509,12 @@ static bool is_dvbv3_delsys(u32 delsys)
        return status;
 }
 
-static int set_delivery_system(struct dvb_frontend *fe, u32 desired_system)
+static int emulate_delivery_system(struct dvb_frontend *fe,
+                                  enum dvbv3_emulation_type type,
+                                  u32 delsys, u32 desired_system)
 {
-       int ncaps, i;
-       u32 delsys = SYS_UNDEFINED;
+       int i;
        struct dtv_frontend_properties *c = &fe->dtv_property_cache;
-       enum dvbv3_emulation_type type;
-
-       /*
-        * It was reported that some old DVBv5 applications were
-        * filling delivery_system with SYS_UNDEFINED. If this happens,
-        * assume that the application wants to use the first supported
-        * delivery system.
-        */
-       if (c->delivery_system == SYS_UNDEFINED)
-               c->delivery_system = fe->ops.delsys[0];
-
-       if (desired_system == SYS_UNDEFINED) {
-               /*
-                * A DVBv3 call doesn't know what's the desired system.
-                * Also, DVBv3 applications don't know that ops.info->type
-                * could be changed, and they simply dies when it doesn't
-                * match.
-                * So, don't change the current delivery system, as it
-                * may be trying to do the wrong thing, like setting an
-                * ISDB-T frontend as DVB-T. Instead, find the closest
-                * DVBv3 system that matches the delivery system.
-                */
-               if (is_dvbv3_delsys(c->delivery_system)) {
-                       dev_dbg(fe->dvb->device,
-                                       "%s: Using delivery system to %d\n",
-                                       __func__, c->delivery_system);
-                       return 0;
-               }
-               type = dvbv3_type(c->delivery_system);
-               switch (type) {
-               case DVBV3_QPSK:
-                       desired_system = SYS_DVBS;
-                       break;
-               case DVBV3_QAM:
-                       desired_system = SYS_DVBC_ANNEX_A;
-                       break;
-               case DVBV3_ATSC:
-                       desired_system = SYS_ATSC;
-                       break;
-               case DVBV3_OFDM:
-                       desired_system = SYS_DVBT;
-                       break;
-               default:
-                       dev_dbg(fe->dvb->device, "%s: This frontend doesn't support DVBv3 calls\n",
-                                       __func__);
-                       return -EINVAL;
-               }
-               /*
-                * Get a delivery system that is compatible with DVBv3
-                * NOTE: in order for this to work with softwares like Kaffeine that
-                *      uses a DVBv5 call for DVB-S2 and a DVBv3 call to go back to
-                *      DVB-S, drivers that support both should put the SYS_DVBS entry
-                *      before the SYS_DVBS2, otherwise it won't switch back to DVB-S.
-                *      The real fix is that userspace applications should not use DVBv3
-                *      and not trust on calling FE_SET_FRONTEND to switch the delivery
-                *      system.
-                */
-               ncaps = 0;
-               while (fe->ops.delsys[ncaps] && ncaps < MAX_DELSYS) {
-                       if (fe->ops.delsys[ncaps] == desired_system) {
-                               delsys = desired_system;
-                               break;
-                       }
-                       ncaps++;
-               }
-               if (delsys == SYS_UNDEFINED) {
-                       dev_dbg(fe->dvb->device, "%s: Couldn't find a delivery system that matches %d\n",
-                                       __func__, desired_system);
-               }
-       } else {
-               /*
-                * This is a DVBv5 call. So, it likely knows the supported
-                * delivery systems.
-                */
-
-               /* Check if the desired delivery system is supported */
-               ncaps = 0;
-               while (fe->ops.delsys[ncaps] && ncaps < MAX_DELSYS) {
-                       if (fe->ops.delsys[ncaps] == desired_system) {
-                               c->delivery_system = desired_system;
-                               dev_dbg(fe->dvb->device,
-                                               "%s: Changing delivery system to %d\n",
-                                               __func__, desired_system);
-                               return 0;
-                       }
-                       ncaps++;
-               }
-               type = dvbv3_type(desired_system);
-
-               /*
-                * The delivery system is not supported. See if it can be
-                * emulated.
-                * The emulation only works if the desired system is one of the
-                * DVBv3 delivery systems
-                */
-               if (!is_dvbv3_delsys(desired_system)) {
-                       dev_dbg(fe->dvb->device,
-                                       "%s: can't use a DVBv3 FE_SET_FRONTEND call on this frontend\n",
-                                       __func__);
-                       return -EINVAL;
-               }
-
-               /*
-                * Get the last non-DVBv3 delivery system that has the same type
-                * of the desired system
-                */
-               ncaps = 0;
-               while (fe->ops.delsys[ncaps] && ncaps < MAX_DELSYS) {
-                       if ((dvbv3_type(fe->ops.delsys[ncaps]) == type) &&
-                           !is_dvbv3_delsys(fe->ops.delsys[ncaps]))
-                               delsys = fe->ops.delsys[ncaps];
-                       ncaps++;
-               }
-               /* There's nothing compatible with the desired delivery system */
-               if (delsys == SYS_UNDEFINED) {
-                       dev_dbg(fe->dvb->device,
-                                       "%s: Incompatible DVBv3 FE_SET_FRONTEND call for this frontend\n",
-                                       __func__);
-                       return -EINVAL;
-               }
-       }
 
        c->delivery_system = delsys;
 
@@ -1648,8 +1528,8 @@ static int set_delivery_system(struct dvb_frontend *fe, u32 desired_system)
         * delivery system is the last one at the ops.delsys[] array
         */
        dev_dbg(fe->dvb->device,
-                       "%s: Using delivery system %d emulated as if it were a %d\n",
-                       __func__, delsys, desired_system);
+               "%s: Using delivery system %d emulated as if it were a %d\n",
+               __func__, delsys, desired_system);
 
        /*
         * For now, handles ISDB-T calls. More code may be needed here for the
@@ -1684,6 +1564,162 @@ static int set_delivery_system(struct dvb_frontend *fe, u32 desired_system)
        return 0;
 }
 
+static int dvbv5_set_delivery_system(struct dvb_frontend *fe,
+                                    u32 desired_system)
+{
+       int ncaps;
+       u32 delsys = SYS_UNDEFINED;
+       struct dtv_frontend_properties *c = &fe->dtv_property_cache;
+       enum dvbv3_emulation_type type;
+
+       /*
+        * It was reported that some old DVBv5 applications were
+        * filling delivery_system with SYS_UNDEFINED. If this happens,
+        * assume that the application wants to use the first supported
+        * delivery system.
+        */
+       if (c->delivery_system == SYS_UNDEFINED)
+               c->delivery_system = fe->ops.delsys[0];
+
+       /*
+       * This is a DVBv5 call. So, it likely knows the supported
+       * delivery systems.
+       */
+
+       /* Check if the desired delivery system is supported */
+       ncaps = 0;
+       while (fe->ops.delsys[ncaps] && ncaps < MAX_DELSYS) {
+               if (fe->ops.delsys[ncaps] == desired_system) {
+                       c->delivery_system = desired_system;
+                       dev_dbg(fe->dvb->device,
+                                       "%s: Changing delivery system to %d\n",
+                                       __func__, desired_system);
+                       return 0;
+               }
+               ncaps++;
+       }
+
+       /*
+        * Need to emulate a delivery system
+        */
+
+       type = dvbv3_type(desired_system);
+
+       /*
+       * The delivery system is not supported. See if it can be
+       * emulated.
+       * The emulation only works if the desired system is one of the
+       * DVBv3 delivery systems
+       */
+       if (!is_dvbv3_delsys(desired_system)) {
+               dev_dbg(fe->dvb->device,
+                       "%s: can't use a DVBv3 FE_SET_FRONTEND call for this frontend\n",
+                       __func__);
+               return -EINVAL;
+       }
+
+       /*
+       * Get the last non-DVBv3 delivery system that has the same type
+       * of the desired system
+       */
+       ncaps = 0;
+       while (fe->ops.delsys[ncaps] && ncaps < MAX_DELSYS) {
+               if ((dvbv3_type(fe->ops.delsys[ncaps]) == type) &&
+                   !is_dvbv3_delsys(fe->ops.delsys[ncaps]))
+                       delsys = fe->ops.delsys[ncaps];
+               ncaps++;
+       }
+       /* There's nothing compatible with the desired delivery system */
+       if (delsys == SYS_UNDEFINED) {
+               dev_dbg(fe->dvb->device,
+                               "%s: Incompatible DVBv3 FE_SET_FRONTEND call for this frontend\n",
+                               __func__);
+               return -EINVAL;
+       }
+
+       return emulate_delivery_system(fe, type, delsys, desired_system);
+}
+
+static int dvbv3_set_delivery_system(struct dvb_frontend *fe)
+{
+       int ncaps;
+       u32 desired_system;
+       u32 delsys = SYS_UNDEFINED;
+       struct dtv_frontend_properties *c = &fe->dtv_property_cache;
+       enum dvbv3_emulation_type type;
+
+       /* If not set yet, defaults to the first supported delivery system */
+       if (c->delivery_system == SYS_UNDEFINED)
+               c->delivery_system = fe->ops.delsys[0];
+
+       /*
+        * A DVBv3 call doesn't know what's the desired system.
+        * Also, DVBv3 applications don't know that ops.info->type
+        * could be changed, and they simply don't tune when it doesn't
+        * match.
+        * So, don't change the current delivery system, as it
+        * may be trying to do the wrong thing, like setting an
+        * ISDB-T frontend as DVB-T. Instead, find the closest
+        * DVBv3 system that matches the delivery system.
+        */
+
+       /*
+        * Trivial case: just use the current one, if it already a DVBv3
+        * delivery system
+        */
+       if (is_dvbv3_delsys(c->delivery_system)) {
+               dev_dbg(fe->dvb->device,
+                               "%s: Using delivery system to %d\n",
+                               __func__, c->delivery_system);
+               return 0;
+       }
+
+       /* Convert from DVBv3 into DVBv5 namespace */
+       type = dvbv3_type(c->delivery_system);
+       switch (type) {
+       case DVBV3_QPSK:
+               desired_system = SYS_DVBS;
+               break;
+       case DVBV3_QAM:
+               desired_system = SYS_DVBC_ANNEX_A;
+               break;
+       case DVBV3_ATSC:
+               desired_system = SYS_ATSC;
+               break;
+       case DVBV3_OFDM:
+               desired_system = SYS_DVBT;
+               break;
+       default:
+               dev_dbg(fe->dvb->device, "%s: This frontend doesn't support DVBv3 calls\n",
+                               __func__);
+               return -EINVAL;
+       }
+
+       /*
+        * Get a delivery system that is compatible with DVBv3
+        * NOTE: in order for this to work with softwares like Kaffeine that
+        *      uses a DVBv5 call for DVB-S2 and a DVBv3 call to go back to
+        *      DVB-S, drivers that support both should put the SYS_DVBS entry
+        *      before the SYS_DVBS2, otherwise it won't switch back to DVB-S.
+        *      The real fix is that userspace applications should not use DVBv3
+        *      and not trust on calling FE_SET_FRONTEND to switch the delivery
+        *      system.
+        */
+       ncaps = 0;
+       while (fe->ops.delsys[ncaps] && ncaps < MAX_DELSYS) {
+               if (fe->ops.delsys[ncaps] == desired_system) {
+                       delsys = desired_system;
+                       break;
+               }
+               ncaps++;
+       }
+       if (delsys == SYS_UNDEFINED) {
+               dev_dbg(fe->dvb->device, "%s: Couldn't find a delivery system that matches %d\n",
+                       __func__, desired_system);
+       }
+       return emulate_delivery_system(fe, type, delsys, desired_system);
+}
+
 static int dtv_property_process_set(struct dvb_frontend *fe,
                                    struct dtv_property *tvp,
                                    struct file *file)
@@ -1742,7 +1778,7 @@ static int dtv_property_process_set(struct dvb_frontend *fe,
                c->rolloff = tvp->u.data;
                break;
        case DTV_DELIVERY_SYSTEM:
-               r = set_delivery_system(fe, tvp->u.data);
+               r = dvbv5_set_delivery_system(fe, tvp->u.data);
                break;
        case DTV_VOLTAGE:
                c->voltage = tvp->u.data;
@@ -2335,7 +2371,7 @@ static int dvb_frontend_ioctl_legacy(struct file *file,
                break;
 
        case FE_SET_FRONTEND:
-               err = set_delivery_system(fe, SYS_UNDEFINED);
+               err = dvbv3_set_delivery_system(fe);
                if (err)
                        break;
 
@@ -2594,7 +2630,7 @@ int dvb_register_frontend(struct dvb_adapter* dvb,
         * first supported delivery system (ops->delsys[0])
         */
 
-        fe->dtv_property_cache.delivery_system = fe->ops.delsys[0];
+       fe->dtv_property_cache.delivery_system = fe->ops.delsys[0];
        dvb_frontend_clear_cache(fe);
 
        mutex_unlock(&frontend_mutex);