Re: [PATCH FOR 3.2 FIX] af9015: limit I2C access to keep FW happy

[Antti Palosaari <crope@iki.fi>]

Mauro,
Don't still but that to the 3.2 as fix. It is not much tested and not 
critical so better put it master for some more testing.

regards
Antti

On 11/13/2011 09:05 PM, Antti Palosaari wrote:
> AF9015 firmware does not like if it gets interrupted by I2C adapter
> request on some critical phases. During normal operation I2C adapter
> is used only 2nd demodulator and tuner on dual tuner devices.
>
> Override demodulator callbacks and use mutex for limit access to
> those "critical" paths to keep AF9015 happy.
>
> Signed-off-by: Antti Palosaari<crope@iki.fi>
> ---
>   drivers/media/dvb/dvb-usb/af9015.c |   97 ++++++++++++++++++++++++++++++++++++
>   drivers/media/dvb/dvb-usb/af9015.h |    7 +++
>   2 files changed, 104 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/media/dvb/dvb-usb/af9015.c b/drivers/media/dvb/dvb-usb/af9015.c
> index c6c275b..033aa8a 100644
> --- a/drivers/media/dvb/dvb-usb/af9015.c
> +++ b/drivers/media/dvb/dvb-usb/af9015.c
> @@ -1093,9 +1093,80 @@ error:
>   	return ret;
>   }
>
> +/* override demod callbacks for resource locking */
> +static int af9015_af9013_set_frontend(struct dvb_frontend *fe,
> +	struct dvb_frontend_parameters *params)
> +{
> +	int ret;
> +	struct dvb_usb_adapter *adap = fe->dvb->priv;
> +	struct af9015_state *priv = adap->dev->priv;
> +
> +	if (mutex_lock_interruptible(&adap->dev->usb_mutex))
> +		return -EAGAIN;
> +
> +	ret = priv->set_frontend[adap->id](fe, params);
> +
> +	mutex_unlock(&adap->dev->usb_mutex);
> +
> +	return ret;
> +}
> +
> +/* override demod callbacks for resource locking */
> +static int af9015_af9013_read_status(struct dvb_frontend *fe,
> +	fe_status_t *status)
> +{
> +	int ret;
> +	struct dvb_usb_adapter *adap = fe->dvb->priv;
> +	struct af9015_state *priv = adap->dev->priv;
> +
> +	if (mutex_lock_interruptible(&adap->dev->usb_mutex))
> +		return -EAGAIN;
> +
> +	ret = priv->read_status[adap->id](fe, status);
> +
> +	mutex_unlock(&adap->dev->usb_mutex);
> +
> +	return ret;
> +}
> +
> +/* override demod callbacks for resource locking */
> +static int af9015_af9013_init(struct dvb_frontend *fe)
> +{
> +	int ret;
> +	struct dvb_usb_adapter *adap = fe->dvb->priv;
> +	struct af9015_state *priv = adap->dev->priv;
> +
> +	if (mutex_lock_interruptible(&adap->dev->usb_mutex))
> +		return -EAGAIN;
> +
> +	ret = priv->init[adap->id](fe);
> +
> +	mutex_unlock(&adap->dev->usb_mutex);
> +
> +	return ret;
> +}
> +
> +/* override demod callbacks for resource locking */
> +static int af9015_af9013_sleep(struct dvb_frontend *fe)
> +{
> +	int ret;
> +	struct dvb_usb_adapter *adap = fe->dvb->priv;
> +	struct af9015_state *priv = adap->dev->priv;
> +
> +	if (mutex_lock_interruptible(&adap->dev->usb_mutex))
> +		return -EAGAIN;
> +
> +	ret = priv->init[adap->id](fe);
> +
> +	mutex_unlock(&adap->dev->usb_mutex);
> +
> +	return ret;
> +}
> +
>   static int af9015_af9013_frontend_attach(struct dvb_usb_adapter *adap)
>   {
>   	int ret;
> +	struct af9015_state *state = adap->dev->priv;
>
>   	if (adap->id == 1) {
>   		/* copy firmware to 2nd demodulator */
> @@ -1116,6 +1187,32 @@ static int af9015_af9013_frontend_attach(struct dvb_usb_adapter *adap)
>   	adap->fe_adap[0].fe = dvb_attach(af9013_attach,&af9015_af9013_config[adap->id],
>   		&adap->dev->i2c_adap);
>
> +	/*
> +	 * AF9015 firmware does not like if it gets interrupted by I2C adapter
> +	 * request on some critical phases. During normal operation I2C adapter
> +	 * is used only 2nd demodulator and tuner on dual tuner devices.
> +	 * Override demodulator callbacks and use mutex for limit access to
> +	 * those "critical" paths to keep AF9015 happy.
> +	 * Note: we abuse unused usb_mutex here.
> +	 */
> +	if (adap->fe_adap[0].fe) {
> +		state->set_frontend[adap->id] =
> +			adap->fe_adap[0].fe->ops.set_frontend;
> +		adap->fe_adap[0].fe->ops.set_frontend =
> +			af9015_af9013_set_frontend;
> +
> +		state->read_status[adap->id] =
> +			adap->fe_adap[0].fe->ops.read_status;
> +		adap->fe_adap[0].fe->ops.read_status =
> +			af9015_af9013_read_status;
> +
> +		state->init[adap->id] = adap->fe_adap[0].fe->ops.init;
> +		adap->fe_adap[0].fe->ops.init = af9015_af9013_init;
> +
> +		state->sleep[adap->id] = adap->fe_adap[0].fe->ops.sleep;
> +		adap->fe_adap[0].fe->ops.sleep = af9015_af9013_sleep;
> +	}
> +
>   	return adap->fe_adap[0].fe == NULL ? -ENODEV : 0;
>   }
>
> diff --git a/drivers/media/dvb/dvb-usb/af9015.h b/drivers/media/dvb/dvb-usb/af9015.h
> index 6252ea6..4a12617 100644
> --- a/drivers/media/dvb/dvb-usb/af9015.h
> +++ b/drivers/media/dvb/dvb-usb/af9015.h
> @@ -102,6 +102,13 @@ struct af9015_state {
>   	u8 rc_repeat;
>   	u32 rc_keycode;
>   	u8 rc_last[4];
> +
> +	/* for demod callback override */
> +	int (*set_frontend[2]) (struct dvb_frontend *fe,
> +		struct dvb_frontend_parameters *params);
> +	int (*read_status[2]) (struct dvb_frontend *fe, fe_status_t *status);
> +	int (*init[2]) (struct dvb_frontend *fe);
> +	int (*sleep[2]) (struct dvb_frontend *fe);
>   };
>
>   struct af9015_config {


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