Re: [PATCH 14/26] dtt200u: don't do DMA on stack

[Patrick Boettcher]

On Fri,  7 Oct 2016 14:24:24 -0300
Mauro Carvalho Chehab <mchehab@xxxxxxxxxxxxxxxx> wrote:

> From: Mauro Carvalho Chehab <mchehab@xxxxxxxxxxxxxxx>
> 
> The USB control messages require DMA to work. We cannot pass
> a stack-allocated buffer, as it is not warranted that the
> stack would be into a DMA enabled area.
> 
> Signed-off-by: Mauro Carvalho Chehab <mchehab@xxxxxxxxxxxxxxx>
> Signed-off-by: Mauro Carvalho Chehab <mchehab@xxxxxxxxxxxxxxxx>
> ---
>  drivers/media/usb/dvb-usb/dtt200u.c | 73
> +++++++++++++++++++++++++------------ 1 file changed, 49
> insertions(+), 24 deletions(-)
> 
> diff --git a/drivers/media/usb/dvb-usb/dtt200u.c
> b/drivers/media/usb/dvb-usb/dtt200u.c index
> d2a01b50af0d..d6023fb6a1d4 100644 ---
> a/drivers/media/usb/dvb-usb/dtt200u.c +++
> b/drivers/media/usb/dvb-usb/dtt200u.c @@ -20,73 +20,88 @@
> MODULE_PARM_DESC(debug, "set debugging level (1=info,xfer=2
> (or-able))." DVB_USB DVB_DEFINE_MOD_OPT_ADAPTER_NR(adapter_nr);
>  
> +struct dtt200u_state {
> +	unsigned char data[80];
> +};
> +
>  static int dtt200u_power_ctrl(struct dvb_usb_device *d, int onoff)
>  {
> -	u8 b = SET_INIT;
> +	struct dtt200u_state *st = d->priv;
> +
> +	st->data[0] = SET_INIT;
>  
>  	if (onoff)
> -		dvb_usb_generic_write(d,&b,2);
> +		dvb_usb_generic_write(d, st->data, 2);
>  
>  	return 0;
>  }
>  
>  static int dtt200u_streaming_ctrl(struct dvb_usb_adapter *adap, int
> onoff) {
> -	u8 b_streaming[2] = { SET_STREAMING, onoff };
> -	u8 b_rst_pid = RESET_PID_FILTER;
> +	struct dtt200u_state *st = adap->dev->priv;
>  
> -	dvb_usb_generic_write(adap->dev, b_streaming, 2);
> +	st->data[0] = SET_STREAMING;
> +	st->data[1] = onoff;
> +
> +	dvb_usb_generic_write(adap->dev, st->data, 2);
> +
> +	if (onoff)
> +		return 0;
> +
> +	st->data[0] = RESET_PID_FILTER;
> +	dvb_usb_generic_write(adap->dev, st->data, 1);
>  
> -	if (onoff == 0)
> -		dvb_usb_generic_write(adap->dev, &b_rst_pid, 1);
>  	return 0;
>  }
>  
>  static int dtt200u_pid_filter(struct dvb_usb_adapter *adap, int
> index, u16 pid, int onoff) {
> -	u8 b_pid[4];
> +	struct dtt200u_state *st = adap->dev->priv;
> +
>  	pid = onoff ? pid : 0;
>  
> -	b_pid[0] = SET_PID_FILTER;
> -	b_pid[1] = index;
> -	b_pid[2] = pid & 0xff;
> -	b_pid[3] = (pid >> 8) & 0x1f;
> +	st->data[0] = SET_PID_FILTER;
> +	st->data[1] = index;
> +	st->data[2] = pid & 0xff;
> +	st->data[3] = (pid >> 8) & 0x1f;
>  
> -	return dvb_usb_generic_write(adap->dev, b_pid, 4);
> +	return dvb_usb_generic_write(adap->dev, st->data, 4);
>  }
>  
>  static int dtt200u_rc_query(struct dvb_usb_device *d)
>  {
> -	u8 key[5],cmd = GET_RC_CODE;
> +	struct dtt200u_state *st = d->priv;
>  	u32 scancode;
>  
> -	dvb_usb_generic_rw(d,&cmd,1,key,5,0);
> -	if (key[0] == 1) {
> +	st->data[0] = GET_RC_CODE;
> +
> +	dvb_usb_generic_rw(d, st->data, 1, st->data, 5, 0);
> +	if (st->data[0] == 1) {
>  		enum rc_type proto = RC_TYPE_NEC;
>  
> -		scancode = key[1];
> -		if ((u8) ~key[1] != key[2]) {
> +		scancode = st->data[1];
> +		if ((u8) ~st->data[1] != st->data[2]) {
>  			/* Extended NEC */
>  			scancode = scancode << 8;
> -			scancode |= key[2];
> +			scancode |= st->data[2];
>  			proto = RC_TYPE_NECX;
>  		}
>  		scancode = scancode << 8;
> -		scancode |= key[3];
> +		scancode |= st->data[3];
>  
>  		/* Check command checksum is ok */
> -		if ((u8) ~key[3] == key[4])
> +		if ((u8) ~st->data[3] == st->data[4])
>  			rc_keydown(d->rc_dev, proto, scancode, 0);
>  		else
>  			rc_keyup(d->rc_dev);
> -	} else if (key[0] == 2) {
> +	} else if (st->data[0] == 2) {
>  		rc_repeat(d->rc_dev);
>  	} else {
>  		rc_keyup(d->rc_dev);
>  	}
>  
> -	if (key[0] != 0)
> -		deb_info("key: %*ph\n", 5, key);
> +	if (st->data[0] != 0)
> +		deb_info("st->data: %*ph\n", 5, st->data);
>  
>  	return 0;
>  }
> @@ -140,6 +155,8 @@ static struct dvb_usb_device_properties
> dtt200u_properties = { .usb_ctrl = CYPRESS_FX2,
>  	.firmware = "dvb-usb-dtt200u-01.fw",
>  
> +	.size_of_priv     = sizeof(struct dtt200u_state),
> +
>  	.num_adapters = 1,
>  	.adapter = {
>  		{
> @@ -190,6 +207,8 @@ static struct dvb_usb_device_properties
> wt220u_properties = { .usb_ctrl = CYPRESS_FX2,
>  	.firmware = "dvb-usb-wt220u-02.fw",
>  
> +	.size_of_priv     = sizeof(struct dtt200u_state),
> +
>  	.num_adapters = 1,
>  	.adapter = {
>  		{
> @@ -240,6 +259,8 @@ static struct dvb_usb_device_properties
> wt220u_fc_properties = { .usb_ctrl = CYPRESS_FX2,
>  	.firmware = "dvb-usb-wt220u-fc03.fw",
>  
> +	.size_of_priv     = sizeof(struct dtt200u_state),
> +
>  	.num_adapters = 1,
>  	.adapter = {
>  		{
> @@ -290,6 +311,8 @@ static struct dvb_usb_device_properties
> wt220u_zl0353_properties = { .usb_ctrl = CYPRESS_FX2,
>  	.firmware = "dvb-usb-wt220u-zl0353-01.fw",
>  
> +	.size_of_priv     = sizeof(struct dtt200u_state),
> +
>  	.num_adapters = 1,
>  	.adapter = {
>  		{
> @@ -340,6 +363,8 @@ static struct dvb_usb_device_properties
> wt220u_miglia_properties = { .usb_ctrl = CYPRESS_FX2,
>  	.firmware = "dvb-usb-wt220u-miglia-01.fw",
>  
> +	.size_of_priv     = sizeof(struct dtt200u_state),
> +
>  	.num_adapters = 1,
>  	.generic_bulk_ctrl_endpoint = 0x01,
>  

Reviewed-By: Patrick Boettcher <patrick.boettcher@xxxxxxxxx>