Re: [PATCH v2] cinergyT2-core: don't do DMA on stack

[Mauro Carvalho Chehab]

Em Wed,  5 Oct 2016 15:54:18 -0300
Mauro Carvalho Chehab  escreveu:

> 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.

Please disregard this patch at linux-doc ML. It was sent to the wrong
list by mistake.

Regards,
Mauro

> 
> Signed-off-by: Mauro Carvalho Chehab 
> ---
> 
> Added the fixups made by Johannes Stezenbach
> 
>  drivers/media/usb/dvb-usb/cinergyT2-core.c | 45 
> ++
>  1 file changed, 27 insertions(+), 18 deletions(-)
> 
> diff --git a/drivers/media/usb/dvb-usb/cinergyT2-core.c 
> b/drivers/media/usb/dvb-usb/cinergyT2-core.c
> index 9fd1527494eb..8267e3777af6 100644
> --- a/drivers/media/usb/dvb-usb/cinergyT2-core.c
> +++ b/drivers/media/usb/dvb-usb/cinergyT2-core.c
> @@ -41,6 +41,7 @@ DVB_DEFINE_MOD_OPT_ADAPTER_NR(adapter_nr);
>  
>  struct cinergyt2_state {
>   u8 rc_counter;
> + unsigned char data[64];
>  };
>  
>  /* We are missing a release hook with usb_device data */
> @@ -50,29 +51,36 @@ static struct dvb_usb_device_properties 
> cinergyt2_properties;
>  
>  static int cinergyt2_streaming_ctrl(struct dvb_usb_adapter *adap, int enable)
>  {
> - char buf[] = { CINERGYT2_EP1_CONTROL_STREAM_TRANSFER, enable ? 1 : 0 };
> - char result[64];
> - return dvb_usb_generic_rw(adap->dev, buf, sizeof(buf), result,
> - sizeof(result), 0);
> + struct dvb_usb_device *d = adap->dev;
> + struct cinergyt2_state *st = d->priv;
> +
> + st->data[0] = CINERGYT2_EP1_CONTROL_STREAM_TRANSFER;
> + st->data[1] = enable ? 1 : 0;
> +
> + return dvb_usb_generic_rw(d, st->data, 2, st->data, 64, 0);
>  }
>  
>  static int cinergyt2_power_ctrl(struct dvb_usb_device *d, int enable)
>  {
> - char buf[] = { CINERGYT2_EP1_SLEEP_MODE, enable ? 0 : 1 };
> - char state[3];
> - return dvb_usb_generic_rw(d, buf, sizeof(buf), state, sizeof(state), 0);
> + struct cinergyt2_state *st = d->priv;
> +
> + st->data[0] = CINERGYT2_EP1_SLEEP_MODE;
> + st->data[1] = enable ? 1 : 0;
> +
> + return dvb_usb_generic_rw(d, st->data, 2, st->data, 3, 0);
>  }
>  
>  static int cinergyt2_frontend_attach(struct dvb_usb_adapter *adap)
>  {
> - char query[] = { CINERGYT2_EP1_GET_FIRMWARE_VERSION };
> - char state[3];
> + struct dvb_usb_device *d = adap->dev;
> + struct cinergyt2_state *st = d->priv;
>   int ret;
>  
>   adap->fe_adap[0].fe = cinergyt2_fe_attach(adap->dev);
>  
> - ret = dvb_usb_generic_rw(adap->dev, query, sizeof(query), state,
> - sizeof(state), 0);
> + st->data[0] = CINERGYT2_EP1_GET_FIRMWARE_VERSION;
> +
> + ret = dvb_usb_generic_rw(d, st->data, 1, st->data, 3, 0);
>   if (ret < 0) {
>   deb_rc("cinergyt2_power_ctrl() Failed to retrieve sleep "
>   "state info\n");
> @@ -141,13 +149,14 @@ static int repeatable_keys[] = {
>  static int cinergyt2_rc_query(struct dvb_usb_device *d, u32 *event, int 
> *state)
>  {
>   struct cinergyt2_state *st = d->priv;
> - u8 key[5] = {0, 0, 0, 0, 0}, cmd = CINERGYT2_EP1_GET_RC_EVENTS;
>   int i;
>  
>   *state = REMOTE_NO_KEY_PRESSED;
>  
> - dvb_usb_generic_rw(d, , 1, key, sizeof(key), 0);
> - if (key[4] == 0xff) {
> + st->data[0] = CINERGYT2_EP1_GET_RC_EVENTS;
> +
> + dvb_usb_generic_rw(d, st->data, 1, st->data, 5, 0);
> + if (st->data[4] == 0xff) {
>   /* key repeat */
>   st->rc_counter++;
>   if (st->rc_counter > RC_REPEAT_DELAY) {
> @@ -166,13 +175,13 @@ static int cinergyt2_rc_query(struct dvb_usb_device *d, 
> u32 *event, int *state)
>   }
>  
>   /* hack to pass checksum on the custom field */
> - key[2] = ~key[1];
> - dvb_usb_nec_rc_key_to_event(d, key, event, state);
> - if (key[0] != 0) {
> + st->data[2] = ~st->data[1];
> + dvb_usb_nec_rc_key_to_event(d, st->data, event, state);
> + if (st->data[0] != 0) {
>   if (*event != d->last_event)
>   st->rc_counter = 0;
>  
> - deb_rc("key: %*ph\n", 5, key);
> + deb_rc("key: %*ph\n", 5, st->data);
>   }
>   return 0;
>  }



Thanks,
Mauro
--
To unsubscribe from this list: send the line "unsubscribe linux-doc" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

[PATCH v2] cinergyT2-core: don't do DMA on stack

[Mauro Carvalho Chehab]

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 
---

Added the fixups made by Johannes Stezenbach

 drivers/media/usb/dvb-usb/cinergyT2-core.c | 45 ++
 1 file changed, 27 insertions(+), 18 deletions(-)

diff --git a/drivers/media/usb/dvb-usb/cinergyT2-core.c 
b/drivers/media/usb/dvb-usb/cinergyT2-core.c
index 9fd1527494eb..8267e3777af6 100644
--- a/drivers/media/usb/dvb-usb/cinergyT2-core.c
+++ b/drivers/media/usb/dvb-usb/cinergyT2-core.c
@@ -41,6 +41,7 @@ DVB_DEFINE_MOD_OPT_ADAPTER_NR(adapter_nr);
 
 struct cinergyt2_state {
u8 rc_counter;
+   unsigned char data[64];
 };
 
 /* We are missing a release hook with usb_device data */
@@ -50,29 +51,36 @@ static struct dvb_usb_device_properties 
cinergyt2_properties;
 
 static int cinergyt2_streaming_ctrl(struct dvb_usb_adapter *adap, int enable)
 {
-   char buf[] = { CINERGYT2_EP1_CONTROL_STREAM_TRANSFER, enable ? 1 : 0 };
-   char result[64];
-   return dvb_usb_generic_rw(adap->dev, buf, sizeof(buf), result,
-   sizeof(result), 0);
+   struct dvb_usb_device *d = adap->dev;
+   struct cinergyt2_state *st = d->priv;
+
+   st->data[0] = CINERGYT2_EP1_CONTROL_STREAM_TRANSFER;
+   st->data[1] = enable ? 1 : 0;
+
+   return dvb_usb_generic_rw(d, st->data, 2, st->data, 64, 0);
 }
 
 static int cinergyt2_power_ctrl(struct dvb_usb_device *d, int enable)
 {
-   char buf[] = { CINERGYT2_EP1_SLEEP_MODE, enable ? 0 : 1 };
-   char state[3];
-   return dvb_usb_generic_rw(d, buf, sizeof(buf), state, sizeof(state), 0);
+   struct cinergyt2_state *st = d->priv;
+
+   st->data[0] = CINERGYT2_EP1_SLEEP_MODE;
+   st->data[1] = enable ? 1 : 0;
+
+   return dvb_usb_generic_rw(d, st->data, 2, st->data, 3, 0);
 }
 
 static int cinergyt2_frontend_attach(struct dvb_usb_adapter *adap)
 {
-   char query[] = { CINERGYT2_EP1_GET_FIRMWARE_VERSION };
-   char state[3];
+   struct dvb_usb_device *d = adap->dev;
+   struct cinergyt2_state *st = d->priv;
int ret;
 
adap->fe_adap[0].fe = cinergyt2_fe_attach(adap->dev);
 
-   ret = dvb_usb_generic_rw(adap->dev, query, sizeof(query), state,
-   sizeof(state), 0);
+   st->data[0] = CINERGYT2_EP1_GET_FIRMWARE_VERSION;
+
+   ret = dvb_usb_generic_rw(d, st->data, 1, st->data, 3, 0);
if (ret < 0) {
deb_rc("cinergyt2_power_ctrl() Failed to retrieve sleep "
"state info\n");
@@ -141,13 +149,14 @@ static int repeatable_keys[] = {
 static int cinergyt2_rc_query(struct dvb_usb_device *d, u32 *event, int *state)
 {
struct cinergyt2_state *st = d->priv;
-   u8 key[5] = {0, 0, 0, 0, 0}, cmd = CINERGYT2_EP1_GET_RC_EVENTS;
int i;
 
*state = REMOTE_NO_KEY_PRESSED;
 
-   dvb_usb_generic_rw(d, , 1, key, sizeof(key), 0);
-   if (key[4] == 0xff) {
+   st->data[0] = CINERGYT2_EP1_GET_RC_EVENTS;
+
+   dvb_usb_generic_rw(d, st->data, 1, st->data, 5, 0);
+   if (st->data[4] == 0xff) {
/* key repeat */
st->rc_counter++;
if (st->rc_counter > RC_REPEAT_DELAY) {
@@ -166,13 +175,13 @@ static int cinergyt2_rc_query(struct dvb_usb_device *d, 
u32 *event, int *state)
}
 
/* hack to pass checksum on the custom field */
-   key[2] = ~key[1];
-   dvb_usb_nec_rc_key_to_event(d, key, event, state);
-   if (key[0] != 0) {
+   st->data[2] = ~st->data[1];
+   dvb_usb_nec_rc_key_to_event(d, st->data, event, state);
+   if (st->data[0] != 0) {
if (*event != d->last_event)
st->rc_counter = 0;
 
-   deb_rc("key: %*ph\n", 5, key);
+   deb_rc("key: %*ph\n", 5, st->data);
}
return 0;
 }
-- 
2.7.4


--
To unsubscribe from this list: send the line "unsubscribe linux-doc" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html