[media] DiBcom: protect the I2C bufer access
This patch protects the I2C buffer access in order to manage concurrent
access. This protection is done using mutex.
Furthermore, for the dib9000, if a pid filtering command is
received during the tuning, this pid filtering command is delayed to
avoid any concurrent access issue.
Cc: Mauro Carvalho Chehab <mchehab@redhat.com>
Cc: Florian Mickler <florian@mickler.org>
Cc: stable@kernel.org
Signed-off-by: Olivier Grenie <olivier.grenie@dibcom.fr>
Signed-off-by: Patrick Boettcher <Patrick.Boettcher@dibcom.fr>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
diff --git a/drivers/media/dvb/frontends/dib7000m.c b/drivers/media/dvb/frontends/dib7000m.c
index 79cb1c2..dbb76d7 100644
--- a/drivers/media/dvb/frontends/dib7000m.c
+++ b/drivers/media/dvb/frontends/dib7000m.c
@@ -11,6 +11,7 @@
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/i2c.h>
+#include <linux/mutex.h>
#include "dvb_frontend.h"
@@ -55,6 +56,7 @@
struct i2c_msg msg[2];
u8 i2c_write_buffer[4];
u8 i2c_read_buffer[2];
+ struct mutex i2c_buffer_lock;
};
enum dib7000m_power_mode {
@@ -69,6 +71,13 @@
static u16 dib7000m_read_word(struct dib7000m_state *state, u16 reg)
{
+ u16 ret;
+
+ if (mutex_lock_interruptible(&state->i2c_buffer_lock) < 0) {
+ dprintk("could not acquire lock");
+ return 0;
+ }
+
state->i2c_write_buffer[0] = (reg >> 8) | 0x80;
state->i2c_write_buffer[1] = reg & 0xff;
@@ -85,11 +94,21 @@
if (i2c_transfer(state->i2c_adap, state->msg, 2) != 2)
dprintk("i2c read error on %d",reg);
- return (state->i2c_read_buffer[0] << 8) | state->i2c_read_buffer[1];
+ ret = (state->i2c_read_buffer[0] << 8) | state->i2c_read_buffer[1];
+ mutex_unlock(&state->i2c_buffer_lock);
+
+ return ret;
}
static int dib7000m_write_word(struct dib7000m_state *state, u16 reg, u16 val)
{
+ int ret;
+
+ if (mutex_lock_interruptible(&state->i2c_buffer_lock) < 0) {
+ dprintk("could not acquire lock");
+ return -EINVAL;
+ }
+
state->i2c_write_buffer[0] = (reg >> 8) & 0xff;
state->i2c_write_buffer[1] = reg & 0xff;
state->i2c_write_buffer[2] = (val >> 8) & 0xff;
@@ -101,7 +120,10 @@
state->msg[0].buf = state->i2c_write_buffer;
state->msg[0].len = 4;
- return i2c_transfer(state->i2c_adap, state->msg, 1) != 1 ? -EREMOTEIO : 0;
+ ret = (i2c_transfer(state->i2c_adap, state->msg, 1) != 1 ?
+ -EREMOTEIO : 0);
+ mutex_unlock(&state->i2c_buffer_lock);
+ return ret;
}
static void dib7000m_write_tab(struct dib7000m_state *state, u16 *buf)
{
@@ -1385,6 +1407,7 @@
demod = &st->demod;
demod->demodulator_priv = st;
memcpy(&st->demod.ops, &dib7000m_ops, sizeof(struct dvb_frontend_ops));
+ mutex_init(&st->i2c_buffer_lock);
st->timf_default = cfg->bw->timf;