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

From: Patrick Boettcher
Date: Mon Oct 10 2016 - 02:36:34 EST


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>