DiBcom: protect the I2C bufer access
commit 79fcce3230b140f7675f8529ee53fe2f9644f902 upstream.
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>
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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;