lkml.org 
[lkml]   [2016]   [Oct]   [11]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH v2 17/31] dtv5100: don't do DMA on stack
Date
From: Mauro Carvalho Chehab <mchehab@osg.samsung.com>

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@osg.samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
---
drivers/media/usb/dvb-usb/dtv5100.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/media/usb/dvb-usb/dtv5100.c b/drivers/media/usb/dvb-usb/dtv5100.c
index 3d11df41cac0..c60fb54f445f 100644
--- a/drivers/media/usb/dvb-usb/dtv5100.c
+++ b/drivers/media/usb/dvb-usb/dtv5100.c
@@ -31,9 +31,14 @@ module_param_named(debug, dvb_usb_dtv5100_debug, int, 0644);
MODULE_PARM_DESC(debug, "set debugging level" DVB_USB_DEBUG_STATUS);
DVB_DEFINE_MOD_OPT_ADAPTER_NR(adapter_nr);

+struct dtv5100_state {
+ unsigned char data[80];
+};
+
static int dtv5100_i2c_msg(struct dvb_usb_device *d, u8 addr,
u8 *wbuf, u16 wlen, u8 *rbuf, u16 rlen)
{
+ struct dtv5100_state *st = d->priv;
u8 request;
u8 type;
u16 value;
@@ -60,9 +65,10 @@ static int dtv5100_i2c_msg(struct dvb_usb_device *d, u8 addr,
}
index = (addr << 8) + wbuf[0];

+ memcpy(st->data, rbuf, rlen);
msleep(1); /* avoid I2C errors */
return usb_control_msg(d->udev, usb_rcvctrlpipe(d->udev, 0), request,
- type, value, index, rbuf, rlen,
+ type, value, index, st->data, rlen,
DTV5100_USB_TIMEOUT);
}

@@ -176,7 +182,7 @@ static struct dvb_usb_device_properties dtv5100_properties = {
.caps = DVB_USB_IS_AN_I2C_ADAPTER,
.usb_ctrl = DEVICE_SPECIFIC,

- .size_of_priv = 0,
+ .size_of_priv = sizeof(struct dtv5100_state),

.num_adapters = 1,
.adapter = {{
--
2.7.4

\
 
 \ /
  Last update: 2016-10-11 12:14    [W:0.262 / U:1.912 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site