[media] dib8000: improves the auto search mode check logic

The logic that detects if auto search mode should be used is too
complex.

Also, it doesn't cover all cases, as the dib8000_tune logic
requires either auto mode or a fully specified manual mode.
So, move it to a separate function and add some extra debug
data to help identifying when it falled back to auto mode,
because the manual settings are invalid.

Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
Acked-by: Patrick Boettcher <pboettcher@kernellabs.com>

diff --git a/drivers/media/dvb-frontends/dib8000.c b/drivers/media/dvb-frontends/dib8000.c
index 063232a..f11c9f8 100644 (file)
--- a/drivers/media/dvb-frontends/dib8000.c
+++ b/drivers/media/dvb-frontends/dib8000.c
@@ -2873,6 +2873,91 @@ static int dib8090p_init_sdram(struct dib8000_state *state)
        return 0;
 }
 
+/**
+ * is_manual_mode - Check if TMCC should be used for parameters settings
+ * @c: struct dvb_frontend_properties
+ *
+ * By default, TMCC table should be used for parameter settings on most
+ * usercases. However, sometimes it is desirable to lock the demod to
+ * use the manual parameters.
+ *
+ * On manual mode, the current dib8000_tune state machine is very restrict:
+ * It requires that both per-layer and per-transponder parameters to be
+ * properly specified, otherwise the device won't lock.
+ *
+ * Check if all those conditions are properly satisfied before allowing
+ * the device to use the manual frequency lock mode.
+ */
+static int is_manual_mode(struct dtv_frontend_properties *c)
+{
+       int i, n_segs = 0;
+
+       /* Use auto mode on DVB-T compat mode */
+       if (c->delivery_system != SYS_ISDBT)
+               return 0;
+
+       /*
+        * Transmission mode is only detected on auto mode, currently
+        */
+       if (c->transmission_mode == TRANSMISSION_MODE_AUTO) {
+               dprintk("transmission mode auto");
+               return 0;
+       }
+
+       /*
+        * Guard interval is only detected on auto mode, currently
+        */
+       if (c->guard_interval == GUARD_INTERVAL_AUTO) {
+               dprintk("guard interval auto");
+               return 0;
+       }
+
+       /*
+        * If no layer is enabled, assume auto mode, as at least one
+        * layer should be enabled
+        */
+       if (!c->isdbt_layer_enabled) {
+               dprintk("no layer modulation specified");
+               return 0;
+       }
+
+       /*
+        * Check if the per-layer parameters aren't auto and
+        * disable a layer if segment count is 0 or invalid.
+        */
+       for (i = 0; i < 3; i++) {
+               if (!(c->isdbt_layer_enabled & 1 << i))
+                       continue;
+
+               if ((c->layer[i].segment_count > 13) ||
+                   (c->layer[i].segment_count == 0)) {
+                       c->isdbt_layer_enabled &= ~(1 << i);
+                       continue;
+               }
+
+               n_segs += c->layer[i].segment_count;
+
+               if ((c->layer[i].modulation == QAM_AUTO) ||
+                   (c->layer[i].fec == FEC_AUTO)) {
+                       dprintk("layer %c has either modulation or FEC auto",
+                               'A' + i);
+                       return 0;
+               }
+       }
+
+       /*
+        * Userspace specified a wrong number of segments.
+        *      fallback to auto mode.
+        */
+       if (n_segs == 0 || n_segs > 13) {
+               dprintk("number of segments is invalid");
+               return 0;
+       }
+
+       /* Everything looks ok for manual mode */
+       return 1;
+}
+
 static int dib8000_tune(struct dvb_frontend *fe)
 {
        struct dib8000_state *state = fe->demodulator_priv;
@@ -2901,37 +2986,14 @@ static int dib8000_tune(struct dvb_frontend *fe)
                        if (state->revision == 0x8090)
                                dib8090p_init_sdram(state);
                        state->status = FE_STATUS_TUNE_PENDING;
-                       if ((c->delivery_system != SYS_ISDBT) ||
-                                       (c->inversion == INVERSION_AUTO) ||
-                                       (c->transmission_mode == TRANSMISSION_MODE_AUTO) ||
-                                       (c->guard_interval == GUARD_INTERVAL_AUTO) ||
-                                       (((c->isdbt_layer_enabled & (1 << 0)) != 0) &&
-                                        (c->layer[0].segment_count != 0xff) &&
-                                        (c->layer[0].segment_count != 0) &&
-                                        ((c->layer[0].modulation == QAM_AUTO) ||
-                                         (c->layer[0].fec == FEC_AUTO))) ||
-                                       (((c->isdbt_layer_enabled & (1 << 1)) != 0) &&
-                                        (c->layer[1].segment_count != 0xff) &&
-                                        (c->layer[1].segment_count != 0) &&
-                                        ((c->layer[1].modulation == QAM_AUTO) ||
-                                         (c->layer[1].fec == FEC_AUTO))) ||
-                                       (((c->isdbt_layer_enabled & (1 << 2)) != 0) &&
-                                        (c->layer[2].segment_count != 0xff) &&
-                                        (c->layer[2].segment_count != 0) &&
-                                        ((c->layer[2].modulation == QAM_AUTO) ||
-                                         (c->layer[2].fec == FEC_AUTO))) ||
-                                       (((c->layer[0].segment_count == 0) ||
-                                         ((c->isdbt_layer_enabled & (1 << 0)) == 0)) &&
-                                        ((c->layer[1].segment_count == 0) ||
-                                         ((c->isdbt_layer_enabled & (2 << 0)) == 0)) &&
-                                        ((c->layer[2].segment_count == 0) || ((c->isdbt_layer_enabled & (3 << 0)) == 0))))
-                               state->channel_parameters_set = 0; /* auto search */
-                       else
-                               state->channel_parameters_set = 1; /* channel parameters are known */
+                       state->channel_parameters_set = is_manual_mode(c);
+
+                       dprintk("Tuning channel on %s search mode",
+                               state->channel_parameters_set ? "manual" : "auto");
 
                        dib8000_viterbi_state(state, 0); /* force chan dec in restart */
 
-                       /* Layer monit */
+                       /* Layer monitor */
                        dib8000_write_word(state, 285, dib8000_read_word(state, 285) & 0x60);
 
                        dib8000_set_frequency_offset(state);