audio.c

linux嵌入式课程实践中的一个关于声卡驱动程序 。

                                ainfo.record.precision =
                                        drv->ops->get_input_precision(drv);
                        else
                                ainfo.record.precision = (8);
                        if (drv->ops->get_input_encoding)
                                ainfo.record.encoding =
                                        drv->ops->get_input_encoding(drv);
                        else
                                ainfo.record.encoding = (AUDIO_ENCODING_ULAW);
                        if (drv->ops->get_input_volume)
                                ainfo.record.gain =
                                        drv->ops->get_input_volume(drv);
                        else
                                ainfo.record.gain = (0);
                        if (drv->ops->get_input_port)
                                ainfo.record.port =
                                        drv->ops->get_input_port(drv);
                        else
                                ainfo.record.port = (0);
                        if (drv->ops->get_input_ports)
                                ainfo.record.avail_ports = 
                                        drv->ops->get_input_ports(drv);
                        else
                                ainfo.record.avail_ports = (0);

                        /* To make e.g. vat happy, we let them think they control this */
                        ainfo.record.buffer_size = drv->buffer_size;
                        if (drv->ops->get_input_samples)
                                ainfo.record.samples = drv->ops->get_input_samples(drv);
                        else
                                ainfo.record.samples = 0;

                        /* This is undefined in the record context in Solaris */
                        ainfo.record.eof = 0;
                        if (drv->ops->get_input_pause)
                                ainfo.record.pause =
                                        drv->ops->get_input_pause(drv);
                        else
                                ainfo.record.pause = 0;
                        if (drv->ops->get_input_error)
                                ainfo.record.error = 
                                        (unsigned char) drv->ops->get_input_error(drv);
                        else
                                ainfo.record.error = 0;
                        ainfo.record.waiting = 0;
                        if (drv->ops->get_input_balance)
                                ainfo.record.balance =
                                        (unsigned char) drv->ops->get_input_balance(drv);
                        else
                                ainfo.record.balance = (unsigned char)(AUDIO_MID_BALANCE);
                        ainfo.record.minordev = 4 + (minor << SPARCAUDIO_DEVICE_SHIFT);
                        ainfo.record.open = (drv->flags & SDF_OPEN_READ);
                        ainfo.record.active = 0;

                        if (drv->ops->get_output_rate)
                                ainfo.play.sample_rate =
                                        drv->ops->get_output_rate(drv);
                        else
                                ainfo.play.sample_rate = (8000);
                        if (drv->ops->get_output_channels)
                                ainfo.play.channels =
                                        drv->ops->get_output_channels(drv);
                        else
                                ainfo.play.channels = (1);
                        if (drv->ops->get_output_precision)
                                ainfo.play.precision =
                                        drv->ops->get_output_precision(drv);
                        else
                                ainfo.play.precision = (8);
                        if (drv->ops->get_output_encoding)
                                ainfo.play.encoding =
                                        drv->ops->get_output_encoding(drv);
                        else
                                ainfo.play.encoding = (AUDIO_ENCODING_ULAW);
                        if (drv->ops->get_output_volume)
                                ainfo.play.gain =
                                        drv->ops->get_output_volume(drv);
                        else
                                ainfo.play.gain = (0);
                        if (drv->ops->get_output_port)
                                ainfo.play.port =
                                        drv->ops->get_output_port(drv);
                        else
                                ainfo.play.port = (0);
                        if (drv->ops->get_output_ports)
                                ainfo.play.avail_ports = 
                                        drv->ops->get_output_ports(drv);
                        else
                                ainfo.play.avail_ports = (0);

                        /* This is not defined in the play context in Solaris */
                        ainfo.play.buffer_size = 0;
                        if (drv->ops->get_output_samples)
                                ainfo.play.samples = drv->ops->get_output_samples(drv);
                        else
                                ainfo.play.samples = 0;
                        ainfo.play.eof = drv->output_eof;
                        if (drv->ops->get_output_pause)
                                ainfo.play.pause =
                                        drv->ops->get_output_pause(drv);
                        else
                                ainfo.play.pause = 0;
                        if (drv->ops->get_output_error)
                                ainfo.play.error =
                                        (unsigned char)drv->ops->get_output_error(drv);
                        else
                                ainfo.play.error = 0;
                        ainfo.play.waiting = waitqueue_active(&drv->open_wait);
                        if (drv->ops->get_output_balance)
                                ainfo.play.balance =
                                        (unsigned char)drv->ops->get_output_balance(drv);
                        else
                                ainfo.play.balance = (unsigned char)(AUDIO_MID_BALANCE);
                        ainfo.play.minordev = 4 + (minor << SPARCAUDIO_DEVICE_SHIFT);
                        ainfo.play.open = (drv->flags & SDF_OPEN_WRITE);
                        ainfo.play.active = drv->output_active;
	    
                        if (drv->ops->get_monitor_volume)
                                ainfo.monitor_gain =
                                        drv->ops->get_monitor_volume(drv);
                        else
                                ainfo.monitor_gain = (0);

                        if (drv->ops->get_output_muted)
                                ainfo.output_muted = 
                                        (unsigned char)drv->ops->get_output_muted(drv);
                        else
                                ainfo.output_muted = (unsigned char)(0);

                        retval = verify_area(VERIFY_WRITE, (void *)arg,
                                             sizeof(struct audio_info));
                        if (retval < 0)
                                break;

                        copy_to_user((struct audio_info *)arg, &ainfo, sizeof(ainfo));
                        break;
                case AUDIO_SETINFO:
                {
                        audio_info_t curinfo, newinfo;
	      
                        if (verify_area(VERIFY_READ, (audio_info_t *)arg, 
                                        sizeof(audio_info_t))) {
                                dprintk(("verify_area failed\n"));
                                return -EINVAL;
                        }
                        copy_from_user(&ainfo, (audio_info_t *)arg, sizeof(audio_info_t));

                        /* Without these there's no point in trying */
                        if (!drv->ops->get_input_precision ||
                            !drv->ops->get_input_channels ||
                            !drv->ops->get_input_rate ||
                            !drv->ops->get_input_encoding ||
                            !drv->ops->get_output_precision ||
                            !drv->ops->get_output_channels ||
                            !drv->ops->get_output_rate ||
                            !drv->ops->get_output_encoding) {
                                eprintk(("missing get routines: failed\n"));
                                retval = -EINVAL;
                                break;
                        }

                        /* Do bounds checking for things which always apply.
                         * Follow with enforcement of basic tenets of certain
                         * encodings. Everything over and above generic is
                         * enforced by the driver, which can assume that
                         * Martian cases are taken care of here.
                         */
                        if (Modify(ainfo.play.gain) && 
                            ((ainfo.play.gain > AUDIO_MAX_GAIN) || 
                             (ainfo.play.gain < AUDIO_MIN_GAIN))) {
                                /* Need to differentiate this from e.g. the above error */
                                eprintk(("play gain bounds: failed %d\n", ainfo.play.gain));
                                retval = -EINVAL;
                                break;
                        }
                        if (Modify(ainfo.record.gain) &&
                            ((ainfo.record.gain > AUDIO_MAX_GAIN) ||
                             (ainfo.record.gain < AUDIO_MIN_GAIN))) {
                                eprintk(("rec gain bounds: failed %d\n", ainfo.record.gain));
                                retval = -EINVAL;
                                break;
                        }
                        if (Modify(ainfo.monitor_gain) &&
                            ((ainfo.monitor_gain > AUDIO_MAX_GAIN) ||
                             (ainfo.monitor_gain < AUDIO_MIN_GAIN))) {
                                eprintk(("monitor gain bounds: failed\n"));
                                retval = -EINVAL;
                                break;
                        }

                        /* Don't need to check less than zero on these */
                        if (Modifyc(ainfo.play.balance) &&
                            (ainfo.play.balance > AUDIO_RIGHT_BALANCE)) {
                                eprintk(("play balance bounds: %d failed\n", 
                                         (int)ainfo.play.balance));
                                retval = -EINVAL;
                                break;
                        }
                        if (Modifyc(ainfo.record.balance) &&
                            (ainfo.record.balance > AUDIO_RIGHT_BALANCE)) {
                                eprintk(("rec balance bounds: failed\n"));
                                retval = -EINVAL;
                                break;
                        }
	      
                        /* If any of these changed, record them all, then make
                         * changes atomically. If something fails, back it all out.
                         */
                        if (Modify(ainfo.record.precision) || 
                            Modify(ainfo.record.sample_rate) ||
                            Modify(ainfo.record.channels) ||
                            Modify(ainfo.record.encoding) || 
                            Modify(ainfo.play.precision) || 
                            Modify(ainfo.play.sample_rate) ||
                            Modify(ainfo.play.channels) ||
                            Modify(ainfo.play.encoding)) {
                                /* If they're trying to change something we
                                 * have no routine for, they lose.
                                 */
                                if ((!drv->ops->set_input_encoding && 
                                     Modify(ainfo.record.encoding)) ||
                                    (!drv->ops->set_input_rate && 
                                     Modify(ainfo.record.sample_rate)) ||
                                    (!drv->ops->set_input_precision && 
                                     Modify(ainfo.record.precision)) ||
                                    (!drv->ops->set_input_channels && 
                                     Modify(ainfo.record.channels))) {
                                        eprintk(("rec set no routines: failed\n"));
                                        retval = -EINVAL;
                                        break;
                                }		  
		  
                                curinfo.record.encoding = 
                                        drv->ops->get_input_encoding(drv);
                                curinfo.record.sample_rate = 
                                        drv->ops->get_input_rate(drv);	   
                                curinfo.record.precision = 
                                        drv->ops->get_input_precision(drv);	   
                                curinfo.record.channels = 
                                        drv->ops->get_input_channels(drv);	   
                                newinfo.record.encoding =
                                        Modify(ainfo.record.encoding) ? 
                                        ainfo.record.encoding :
                                        curinfo.record.encoding;
                                newinfo.record.sample_rate =
                                        Modify(ainfo.record.sample_rate) ?
                                        ainfo.record.sample_rate :
                                        curinfo.record.sample_rate;
                                newinfo.record.precision =
                                        Modify(ainfo.record.precision) ? 
                                        ainfo.record.precision :
                                        curinfo.record.precision;
                                newinfo.record.channels =
                                        Modify(ainfo.record.channels) ? 
                                        ainfo.record.channels :
                                        curinfo.record.channels;
		    
                                switch (newinfo.record.encoding) {
                                case AUDIO_ENCODING_ALAW:
                                case AUDIO_ENCODING_ULAW:
                                        if (newinfo.record.precision != 8) {
                                                eprintk(("rec law precision bounds: "
                                                         "failed\n"));
                                                retval = -EINVAL;
                                                break;
                                        }
                                        if (newinfo.record.channels != 1) {
                                                eprintk(("rec law channel bounds: "
                                                         "failed\n"));
                                                retval = -EINVAL;
                                                break;
                                        }