[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>

1 files changed, 165 insertions, 129 deletions

diff --git a/drivers/media/dvb-core/dvb_frontend.c b/drivers/media/dvb-core/dvb_frontend.c
index 6e50a7581568..d0d193d1404a 100644
--- 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);