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path: root/drivers/i2c/i2c-core-smbus.c
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Diffstat (limited to 'drivers/i2c/i2c-core-smbus.c')
-rw-r--r--drivers/i2c/i2c-core-smbus.c45
1 files changed, 39 insertions, 6 deletions
diff --git a/drivers/i2c/i2c-core-smbus.c b/drivers/i2c/i2c-core-smbus.c
index a1082c04ac5c..59d5cf376f6a 100644
--- a/drivers/i2c/i2c-core-smbus.c
+++ b/drivers/i2c/i2c-core-smbus.c
@@ -18,6 +18,7 @@
#include <linux/err.h>
#include <linux/i2c.h>
#include <linux/i2c-smbus.h>
+#include <linux/slab.h>
#define CREATE_TRACE_POINTS
#include <trace/events/smbus.h>
@@ -291,6 +292,22 @@ s32 i2c_smbus_write_i2c_block_data(const struct i2c_client *client, u8 command,
}
EXPORT_SYMBOL(i2c_smbus_write_i2c_block_data);
+static void i2c_smbus_try_get_dmabuf(struct i2c_msg *msg, u8 init_val)
+{
+ bool is_read = msg->flags & I2C_M_RD;
+ unsigned char *dma_buf;
+
+ dma_buf = kzalloc(I2C_SMBUS_BLOCK_MAX + (is_read ? 2 : 3), GFP_KERNEL);
+ if (!dma_buf)
+ return;
+
+ msg->buf = dma_buf;
+ msg->flags |= I2C_M_DMA_SAFE;
+
+ if (init_val)
+ msg->buf[0] = init_val;
+}
+
/* Simulate a SMBus command using the i2c protocol
No checking of parameters is done! */
static s32 i2c_smbus_xfer_emulated(struct i2c_adapter *adapter, u16 addr,
@@ -368,6 +385,7 @@ static s32 i2c_smbus_xfer_emulated(struct i2c_adapter *adapter, u16 addr,
msg[1].flags |= I2C_M_RECV_LEN;
msg[1].len = 1; /* block length will be added by
the underlying bus driver */
+ i2c_smbus_try_get_dmabuf(&msg[1], 0);
} else {
msg[0].len = data->block[0] + 2;
if (msg[0].len > I2C_SMBUS_BLOCK_MAX + 2) {
@@ -376,8 +394,10 @@ static s32 i2c_smbus_xfer_emulated(struct i2c_adapter *adapter, u16 addr,
data->block[0]);
return -EINVAL;
}
+
+ i2c_smbus_try_get_dmabuf(&msg[0], command);
for (i = 1; i < msg[0].len; i++)
- msgbuf0[i] = data->block[i-1];
+ msg[0].buf[i] = data->block[i - 1];
}
break;
case I2C_SMBUS_BLOCK_PROC_CALL:
@@ -389,12 +409,16 @@ static s32 i2c_smbus_xfer_emulated(struct i2c_adapter *adapter, u16 addr,
data->block[0]);
return -EINVAL;
}
+
msg[0].len = data->block[0] + 2;
+ i2c_smbus_try_get_dmabuf(&msg[0], command);
for (i = 1; i < msg[0].len; i++)
- msgbuf0[i] = data->block[i-1];
+ msg[0].buf[i] = data->block[i - 1];
+
msg[1].flags |= I2C_M_RECV_LEN;
msg[1].len = 1; /* block length will be added by
the underlying bus driver */
+ i2c_smbus_try_get_dmabuf(&msg[1], 0);
break;
case I2C_SMBUS_I2C_BLOCK_DATA:
if (data->block[0] > I2C_SMBUS_BLOCK_MAX) {
@@ -406,10 +430,13 @@ static s32 i2c_smbus_xfer_emulated(struct i2c_adapter *adapter, u16 addr,
if (read_write == I2C_SMBUS_READ) {
msg[1].len = data->block[0];
+ i2c_smbus_try_get_dmabuf(&msg[1], 0);
} else {
msg[0].len = data->block[0] + 1;
+
+ i2c_smbus_try_get_dmabuf(&msg[0], command);
for (i = 1; i <= data->block[0]; i++)
- msgbuf0[i] = data->block[i];
+ msg[0].buf[i] = data->block[i];
}
break;
default:
@@ -457,14 +484,20 @@ static s32 i2c_smbus_xfer_emulated(struct i2c_adapter *adapter, u16 addr,
break;
case I2C_SMBUS_I2C_BLOCK_DATA:
for (i = 0; i < data->block[0]; i++)
- data->block[i+1] = msgbuf1[i];
+ data->block[i + 1] = msg[1].buf[i];
break;
case I2C_SMBUS_BLOCK_DATA:
case I2C_SMBUS_BLOCK_PROC_CALL:
- for (i = 0; i < msgbuf1[0] + 1; i++)
- data->block[i] = msgbuf1[i];
+ for (i = 0; i < msg[1].buf[0] + 1; i++)
+ data->block[i] = msg[1].buf[i];
break;
}
+
+ if (msg[0].flags & I2C_M_DMA_SAFE)
+ kfree(msg[0].buf);
+ if (msg[1].flags & I2C_M_DMA_SAFE)
+ kfree(msg[1].buf);
+
return 0;
}