i2c: tiny-usb: do not use stack as URB transfer_buffer

Patch fixes i2c-tiny-usb not to use stack as URB transfer_buffer. URB buffers
need to be DMA-able, which stack is not.

Patch is only compile tested.

Signed-off-by: Jussi Kivilinna <jussi.kivilinna@iki.fi>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

1 files changed, 34 insertions, 15 deletions

diff --git a/drivers/i2c/busses/i2c-tiny-usb.c b/drivers/i2c/busses/i2c-tiny-usb.c
index 05106368d405..e7d3b755af3b 100644
--- a/drivers/i2c/busses/i2c-tiny-usb.c
+++ b/drivers/i2c/busses/i2c-tiny-usb.c
@@ -54,12 +54,16 @@ static int usb_write(struct i2c_adapter *adapter, int cmd,
 
 static int usb_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs, int num)
 {
-        unsigned char status;
+        unsigned char *pstatus;
         struct i2c_msg *pmsg;
-        int i;
+        int i, ret;
 
         dev_dbg(&adapter->dev, "master xfer %d messages:\n", num);
 
+        pstatus = kmalloc(sizeof(*pstatus), GFP_KERNEL);
+        if (!pstatus)
+                return -ENOMEM;
+
         for (i = 0 ; i < num ; i++) {
                 int cmd = CMD_I2C_IO;
 
@@ -84,7 +88,8 @@ static int usb_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs, int num)
                                      pmsg->buf, pmsg->len) != pmsg->len) {
                                 dev_err(&adapter->dev,
                                         "failure reading data\n");
-                                return -EREMOTEIO;
+                                ret = -EREMOTEIO;
+                                goto out;
                         }
                 } else {
                         /* write data */
@@ -93,36 +98,50 @@ static int usb_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs, int num)
                                       pmsg->buf, pmsg->len) != pmsg->len) {
                                 dev_err(&adapter->dev,
                                         "failure writing data\n");
-                                return -EREMOTEIO;
+                                ret = -EREMOTEIO;
+                                goto out;
                         }
                 }
 
                 /* read status */
-                if (usb_read(adapter, CMD_GET_STATUS, 0, 0, &status, 1) != 1) {
+                if (usb_read(adapter, CMD_GET_STATUS, 0, 0, pstatus, 1) != 1) {
                         dev_err(&adapter->dev, "failure reading status\n");
-                        return -EREMOTEIO;
+                        ret = -EREMOTEIO;
+                        goto out;
                 }
 
-                dev_dbg(&adapter->dev, "  status = %d\n", status);
-                if (status == STATUS_ADDRESS_NAK)
-                        return -EREMOTEIO;
+                dev_dbg(&adapter->dev, "  status = %d\n", *pstatus);
+                if (*pstatus == STATUS_ADDRESS_NAK) {
+                        ret = -EREMOTEIO;
+                        goto out;
+                }
         }
 
-        return i;
+        ret = i;
+out:
+        kfree(pstatus);
+        return ret;
 }
 
 static u32 usb_func(struct i2c_adapter *adapter)
 {
-        __le32 func;
+        __le32 *pfunc;
+        u32 ret;
+
+        pfunc = kmalloc(sizeof(*pfunc), GFP_KERNEL);
 
         /* get functionality from adapter */
-        if (usb_read(adapter, CMD_GET_FUNC, 0, 0, &func, sizeof(func)) !=
-            sizeof(func)) {
+        if (!pfunc || usb_read(adapter, CMD_GET_FUNC, 0, 0, pfunc,
+                               sizeof(*pfunc)) != sizeof(*pfunc)) {
                 dev_err(&adapter->dev, "failure reading functionality\n");
-                return 0;
+                ret = 0;
+                goto out;
         }
 
-        return le32_to_cpu(func);
+        ret = le32_to_cpup(pfunc);
+out:
+        kfree(pfunc);
+        return ret;
 }
 
 /* This is the actual algorithm we define */