[PATCH v2 06/31] cxusb: don't do DMA on stack

From: Mauro Carvalho Chehab
Date: Tue Oct 11 2016 - 06:14:18 EST


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.

Reviewed-By: Patrick Boettcher <patrick.boettcher@xxxxxxxxx>
Signed-off-by: Mauro Carvalho Chehab <mchehab@xxxxxxxxxxxxxxxx>
---
drivers/media/usb/dvb-usb/cxusb.c | 62 ++++++++++++++++++++++-----------------
drivers/media/usb/dvb-usb/cxusb.h | 6 ++++
2 files changed, 41 insertions(+), 27 deletions(-)

diff --git a/drivers/media/usb/dvb-usb/cxusb.c b/drivers/media/usb/dvb-usb/cxusb.c
index 907ac01ae297..39772812269d 100644
--- a/drivers/media/usb/dvb-usb/cxusb.c
+++ b/drivers/media/usb/dvb-usb/cxusb.c
@@ -45,9 +45,6 @@
#include "si2168.h"
#include "si2157.h"

-/* Max transfer size done by I2C transfer functions */
-#define MAX_XFER_SIZE 80
-
/* debug */
static int dvb_usb_cxusb_debug;
module_param_named(debug, dvb_usb_cxusb_debug, int, 0644);
@@ -61,23 +58,27 @@ DVB_DEFINE_MOD_OPT_ADAPTER_NR(adapter_nr);
static int cxusb_ctrl_msg(struct dvb_usb_device *d,
u8 cmd, u8 *wbuf, int wlen, u8 *rbuf, int rlen)
{
- int wo = (rbuf == NULL || rlen == 0); /* write-only */
- u8 sndbuf[MAX_XFER_SIZE];
+ struct cxusb_state *st = d->priv;
+ int ret, wo;

- if (1 + wlen > sizeof(sndbuf)) {
- warn("i2c wr: len=%d is too big!\n",
- wlen);
+ if (1 + wlen > MAX_XFER_SIZE) {
+ warn("i2c wr: len=%d is too big!\n", wlen);
return -EOPNOTSUPP;
}

- memset(sndbuf, 0, 1+wlen);
+ wo = (rbuf == NULL || rlen == 0); /* write-only */

- sndbuf[0] = cmd;
- memcpy(&sndbuf[1], wbuf, wlen);
+ mutex_lock(&st->data_mutex);
+ st->data[0] = cmd;
+ memcpy(&st->data[1], wbuf, wlen);
if (wo)
- return dvb_usb_generic_write(d, sndbuf, 1+wlen);
+ ret = dvb_usb_generic_write(d, st->data, 1 + wlen);
else
- return dvb_usb_generic_rw(d, sndbuf, 1+wlen, rbuf, rlen, 0);
+ ret = dvb_usb_generic_rw(d, st->data, 1 + wlen,
+ rbuf, rlen, 0);
+
+ mutex_unlock(&st->data_mutex);
+ return ret;
}

/* GPIO */
@@ -1460,36 +1461,43 @@ static struct dvb_usb_device_properties cxusb_mygica_t230_properties;
static int cxusb_probe(struct usb_interface *intf,
const struct usb_device_id *id)
{
+ struct dvb_usb_device *d;
+ struct cxusb_state *st;
+
if (0 == dvb_usb_device_init(intf, &cxusb_medion_properties,
- THIS_MODULE, NULL, adapter_nr) ||
+ THIS_MODULE, &d, adapter_nr) ||
0 == dvb_usb_device_init(intf, &cxusb_bluebird_lgh064f_properties,
- THIS_MODULE, NULL, adapter_nr) ||
+ THIS_MODULE, &d, adapter_nr) ||
0 == dvb_usb_device_init(intf, &cxusb_bluebird_dee1601_properties,
- THIS_MODULE, NULL, adapter_nr) ||
+ THIS_MODULE, &d, adapter_nr) ||
0 == dvb_usb_device_init(intf, &cxusb_bluebird_lgz201_properties,
- THIS_MODULE, NULL, adapter_nr) ||
+ THIS_MODULE, &d, adapter_nr) ||
0 == dvb_usb_device_init(intf, &cxusb_bluebird_dtt7579_properties,
- THIS_MODULE, NULL, adapter_nr) ||
+ THIS_MODULE, &d, adapter_nr) ||
0 == dvb_usb_device_init(intf, &cxusb_bluebird_dualdig4_properties,
- THIS_MODULE, NULL, adapter_nr) ||
+ THIS_MODULE, &d, adapter_nr) ||
0 == dvb_usb_device_init(intf, &cxusb_bluebird_nano2_properties,
- THIS_MODULE, NULL, adapter_nr) ||
+ THIS_MODULE, &d, adapter_nr) ||
0 == dvb_usb_device_init(intf,
&cxusb_bluebird_nano2_needsfirmware_properties,
- THIS_MODULE, NULL, adapter_nr) ||
+ THIS_MODULE, &d, adapter_nr) ||
0 == dvb_usb_device_init(intf, &cxusb_aver_a868r_properties,
- THIS_MODULE, NULL, adapter_nr) ||
+ THIS_MODULE, &d, adapter_nr) ||
0 == dvb_usb_device_init(intf,
&cxusb_bluebird_dualdig4_rev2_properties,
- THIS_MODULE, NULL, adapter_nr) ||
+ THIS_MODULE, &d, adapter_nr) ||
0 == dvb_usb_device_init(intf, &cxusb_d680_dmb_properties,
- THIS_MODULE, NULL, adapter_nr) ||
+ THIS_MODULE, &d, adapter_nr) ||
0 == dvb_usb_device_init(intf, &cxusb_mygica_d689_properties,
- THIS_MODULE, NULL, adapter_nr) ||
+ THIS_MODULE, &d, adapter_nr) ||
0 == dvb_usb_device_init(intf, &cxusb_mygica_t230_properties,
- THIS_MODULE, NULL, adapter_nr) ||
- 0)
+ THIS_MODULE, &d, adapter_nr) ||
+ 0) {
+ st = d->priv;
+ mutex_init(&st->data_mutex);
+
return 0;
+ }

return -EINVAL;
}
diff --git a/drivers/media/usb/dvb-usb/cxusb.h b/drivers/media/usb/dvb-usb/cxusb.h
index 527ff7905e15..9f3ee0e47d5c 100644
--- a/drivers/media/usb/dvb-usb/cxusb.h
+++ b/drivers/media/usb/dvb-usb/cxusb.h
@@ -28,10 +28,16 @@
#define CMD_ANALOG 0x50
#define CMD_DIGITAL 0x51

+/* Max transfer size done by I2C transfer functions */
+#define MAX_XFER_SIZE 80
+
struct cxusb_state {
u8 gpio_write_state[3];
struct i2c_client *i2c_client_demod;
struct i2c_client *i2c_client_tuner;
+
+ unsigned char data[MAX_XFER_SIZE];
+ struct mutex data_mutex;
};

#endif
--
2.7.4