i2c: i2c-tiny-usb: fix buffer not being DMA capable

Since v4.9 i2c-tiny-usb generates the below call trace and longer works, since it can't communicate with the USB device. The reason is, that since v4.9 the USB stack checks, that the buffer it should transfer is DMA capable. This was a requirement since v2.2 days, but it usually worked nevertheless. [ 17.504959] ------------[ cut here ]------------ [ 17.505488] WARNING: CPU: 0 PID: 93 at drivers/usb/core/hcd.c:1587 usb_hcd_map_urb_for_dma+0x37c/0x570 [ 17.506545] transfer buffer not dma capable [ 17.507022] Modules linked in: [ 17.507370] CPU: 0 PID: 93 Comm: i2cdetect Not tainted 4.11.0-rc8+ #10 [ 17.508103] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014 [ 17.509039] Call Trace: [ 17.509320] ? dump_stack+0x5c/0x78 [ 17.509714] ? __warn+0xbe/0xe0 [ 17.510073] ? warn_slowpath_fmt+0x5a/0x80 [ 17.510532] ? nommu_map_sg+0xb0/0xb0 [ 17.510949] ? usb_hcd_map_urb_for_dma+0x37c/0x570 [ 17.511482] ? usb_hcd_submit_urb+0x336/0xab0 [ 17.511976] ? wait_for_completion_timeout+0x12f/0x1a0 [ 17.512549] ? wait_for_completion_timeout+0x65/0x1a0 [ 17.513125] ? usb_start_wait_urb+0x65/0x160 [ 17.513604] ? usb_control_msg+0xdc/0x130 [ 17.514061] ? usb_xfer+0xa4/0x2a0 [ 17.514445] ? __i2c_transfer+0x108/0x3c0 [ 17.514899] ? i2c_transfer+0x57/0xb0 [ 17.515310] ? i2c_smbus_xfer_emulated+0x12f/0x590 [ 17.515851] ? _raw_spin_unlock_irqrestore+0x11/0x20 [ 17.516408] ? i2c_smbus_xfer+0x125/0x330 [ 17.516876] ? i2c_smbus_xfer+0x125/0x330 [ 17.517329] ? i2cdev_ioctl_smbus+0x1c1/0x2b0 [ 17.517824] ? i2cdev_ioctl+0x75/0x1c0 [ 17.518248] ? do_vfs_ioctl+0x9f/0x600 [ 17.518671] ? vfs_write+0x144/0x190 [ 17.519078] ? SyS_ioctl+0x74/0x80 [ 17.519463] ? entry_SYSCALL_64_fastpath+0x1e/0xad [ 17.519959] ---[ end trace d047c04982f5ac50 ]--- Cc: <[email protected]> Signed-off-by: Sebastian Reichel <[email protected]> Reviewed-by: Greg Kroah-Hartman <[email protected]> Acked-by: Till Harbaum <[email protected]> Signed-off-by: Wolfram Sang <[email protected]>
dabrace · May 22, 2017 · 5165da5 · 5165da5
1 parent 0833289
commit 5165da5
Showing 1 changed file with 21 additions and 4 deletions.
diff --git a/drivers/i2c/busses/i2c-tiny-usb.c b/drivers/i2c/busses/i2c-tiny-usb.c
@@ -178,22 +178,39 @@ static int usb_read(struct i2c_adapter *adapter, int cmd,
 		    int value, int index, void *data, int len)
 {
 	struct i2c_tiny_usb *dev = (struct i2c_tiny_usb *)adapter->algo_data;
+	void *dmadata = kmalloc(len, GFP_KERNEL);
+	int ret;
+
+	if (!dmadata)
+		return -ENOMEM;
 
 	/* do control transfer */
-	return usb_control_msg(dev->usb_dev, usb_rcvctrlpipe(dev->usb_dev, 0),
+	ret = usb_control_msg(dev->usb_dev, usb_rcvctrlpipe(dev->usb_dev, 0),
 			       cmd, USB_TYPE_VENDOR | USB_RECIP_INTERFACE |
-			       USB_DIR_IN, value, index, data, len, 2000);
+			       USB_DIR_IN, value, index, dmadata, len, 2000);
+
+	memcpy(data, dmadata, len);
+	kfree(dmadata);
+	return ret;
 }
 
 static int usb_write(struct i2c_adapter *adapter, int cmd,
 		     int value, int index, void *data, int len)
 {
 	struct i2c_tiny_usb *dev = (struct i2c_tiny_usb *)adapter->algo_data;
+	void *dmadata = kmemdup(data, len, GFP_KERNEL);
+	int ret;
+
+	if (!dmadata)
+		return -ENOMEM;
 
 	/* do control transfer */
-	return usb_control_msg(dev->usb_dev, usb_sndctrlpipe(dev->usb_dev, 0),
+	ret = usb_control_msg(dev->usb_dev, usb_sndctrlpipe(dev->usb_dev, 0),
 			       cmd, USB_TYPE_VENDOR | USB_RECIP_INTERFACE,
-			       value, index, data, len, 2000);
+			       value, index, dmadata, len, 2000);
+
+	kfree(dmadata);
+	return ret;
 }
 
 static void i2c_tiny_usb_free(struct i2c_tiny_usb *dev)