[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/dib0070.c b/drivers/media/dvb/frontends/dib0070.c
index 1d47d4d..dc1cb17 100644
--- a/drivers/media/dvb/frontends/dib0070.c
+++ b/drivers/media/dvb/frontends/dib0070.c
@@ -27,6 +27,7 @@
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/i2c.h>
+#include <linux/mutex.h>
#include "dvb_frontend.h"
@@ -78,10 +79,18 @@
struct i2c_msg msg[2];
u8 i2c_write_buffer[3];
u8 i2c_read_buffer[2];
+ struct mutex i2c_buffer_lock;
};
-static uint16_t dib0070_read_reg(struct dib0070_state *state, u8 reg)
+static u16 dib0070_read_reg(struct dib0070_state *state, u8 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;
memset(state->msg, 0, 2 * sizeof(struct i2c_msg));
@@ -96,13 +105,23 @@
if (i2c_transfer(state->i2c, state->msg, 2) != 2) {
printk(KERN_WARNING "DiB0070 I2C read failed\n");
- return 0;
- }
- return (state->i2c_read_buffer[0] << 8) | state->i2c_read_buffer[1];
+ ret = 0;
+ } else
+ ret = (state->i2c_read_buffer[0] << 8)
+ | state->i2c_read_buffer[1];
+
+ mutex_unlock(&state->i2c_buffer_lock);
+ return ret;
}
static int dib0070_write_reg(struct dib0070_state *state, u8 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;
state->i2c_write_buffer[1] = val >> 8;
state->i2c_write_buffer[2] = val & 0xff;
@@ -115,9 +134,12 @@
if (i2c_transfer(state->i2c, state->msg, 1) != 1) {
printk(KERN_WARNING "DiB0070 I2C write failed\n");
- return -EREMOTEIO;
- }
- return 0;
+ ret = -EREMOTEIO;
+ } else
+ ret = 0;
+
+ mutex_unlock(&state->i2c_buffer_lock);
+ return ret;
}
#define HARD_RESET(state) do { \
@@ -734,6 +756,7 @@
state->cfg = cfg;
state->i2c = i2c;
state->fe = fe;
+ mutex_init(&state->i2c_buffer_lock);
fe->tuner_priv = state;
if (dib0070_reset(fe) != 0)
