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/dib8000.c b/drivers/media/dvb/frontends/dib8000.c
index 7d2ea11..fe284d5 100644
--- a/drivers/media/dvb/frontends/dib8000.c
+++ b/drivers/media/dvb/frontends/dib8000.c
@@ -10,6 +10,8 @@
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/i2c.h>
+#include <linux/mutex.h>
+
#include "dvb_math.h"
#include "dvb_frontend.h"
@@ -37,6 +39,7 @@
u8 addr;
u8 *i2c_write_buffer;
u8 *i2c_read_buffer;
+ struct mutex *i2c_buffer_lock;
};
struct dib8000_state {
@@ -77,6 +80,7 @@
struct i2c_msg msg[2];
u8 i2c_write_buffer[4];
u8 i2c_read_buffer[2];
+ struct mutex i2c_buffer_lock;
};
enum dib8000_power_mode {
@@ -86,24 +90,39 @@
static u16 dib8000_i2c_read16(struct i2c_device *i2c, u16 reg)
{
+ u16 ret;
struct i2c_msg msg[2] = {
- {.addr = i2c->addr >> 1, .flags = 0,
- .buf = i2c->i2c_write_buffer, .len = 2},
- {.addr = i2c->addr >> 1, .flags = I2C_M_RD,
- .buf = i2c->i2c_read_buffer, .len = 2},
+ {.addr = i2c->addr >> 1, .flags = 0, .len = 2},
+ {.addr = i2c->addr >> 1, .flags = I2C_M_RD, .len = 2},
};
+ if (mutex_lock_interruptible(i2c->i2c_buffer_lock) < 0) {
+ dprintk("could not acquire lock");
+ return 0;
+ }
+
+ msg[0].buf = i2c->i2c_write_buffer;
msg[0].buf[0] = reg >> 8;
msg[0].buf[1] = reg & 0xff;
+ msg[1].buf = i2c->i2c_read_buffer;
if (i2c_transfer(i2c->adap, msg, 2) != 2)
dprintk("i2c read error on %d", reg);
- return (msg[1].buf[0] << 8) | msg[1].buf[1];
+ ret = (msg[1].buf[0] << 8) | msg[1].buf[1];
+ mutex_unlock(i2c->i2c_buffer_lock);
+ return ret;
}
static u16 dib8000_read_word(struct dib8000_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;
state->i2c_write_buffer[1] = reg & 0xff;
@@ -120,7 +139,10 @@
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 u32 dib8000_read32(struct dib8000_state *state, u16 reg)
@@ -135,22 +157,35 @@
static int dib8000_i2c_write16(struct i2c_device *i2c, u16 reg, u16 val)
{
- struct i2c_msg msg = {.addr = i2c->addr >> 1, .flags = 0,
- .buf = i2c->i2c_write_buffer, .len = 4};
+ struct i2c_msg msg = {.addr = i2c->addr >> 1, .flags = 0, .len = 4};
int ret = 0;
+ if (mutex_lock_interruptible(i2c->i2c_buffer_lock) < 0) {
+ dprintk("could not acquire lock");
+ return -EINVAL;
+ }
+
+ msg.buf = i2c->i2c_write_buffer;
msg.buf[0] = (reg >> 8) & 0xff;
msg.buf[1] = reg & 0xff;
msg.buf[2] = (val >> 8) & 0xff;
msg.buf[3] = val & 0xff;
ret = i2c_transfer(i2c->adap, &msg, 1) != 1 ? -EREMOTEIO : 0;
+ mutex_unlock(i2c->i2c_buffer_lock);
return ret;
}
static int dib8000_write_word(struct dib8000_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;
@@ -162,7 +197,11 @@
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 const s16 coeff_2k_sb_1seg_dqpsk[8] = {
@@ -2434,8 +2473,15 @@
if (!client.i2c_read_buffer) {
dprintk("%s: not enough memory", __func__);
ret = -ENOMEM;
- goto error_memory;
+ goto error_memory_read;
}
+ client.i2c_buffer_lock = kzalloc(sizeof(struct mutex), GFP_KERNEL);
+ if (!client.i2c_buffer_lock) {
+ dprintk("%s: not enough memory", __func__);
+ ret = -ENOMEM;
+ goto error_memory_lock;
+ }
+ mutex_init(client.i2c_buffer_lock);
for (k = no_of_demods - 1; k >= 0; k--) {
/* designated i2c address */
@@ -2476,8 +2522,10 @@
}
error:
+ kfree(client.i2c_buffer_lock);
+error_memory_lock:
kfree(client.i2c_read_buffer);
-error_memory:
+error_memory_read:
kfree(client.i2c_write_buffer);
return ret;
@@ -2581,6 +2629,8 @@
state->i2c.addr = i2c_addr;
state->i2c.i2c_write_buffer = state->i2c_write_buffer;
state->i2c.i2c_read_buffer = state->i2c_read_buffer;
+ mutex_init(&state->i2c_buffer_lock);
+ state->i2c.i2c_buffer_lock = &state->i2c_buffer_lock;
state->gpio_val = cfg->gpio_val;
state->gpio_dir = cfg->gpio_dir;