From 5165da5923d6c7df6f2927b0113b2e4d9288661e Mon Sep 17 00:00:00 2001 From: Sebastian Reichel Date: Fri, 5 May 2017 11:06:50 +0200 Subject: [PATCH] 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: Signed-off-by: Sebastian Reichel Reviewed-by: Greg Kroah-Hartman Acked-by: Till Harbaum Signed-off-by: Wolfram Sang --- drivers/i2c/busses/i2c-tiny-usb.c | 25 +++++++++++++++++++++---- 1 file changed, 21 insertions(+), 4 deletions(-) diff --git a/drivers/i2c/busses/i2c-tiny-usb.c b/drivers/i2c/busses/i2c-tiny-usb.c index 0ed77ee..a2e3dd7 100644 --- 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) -- 2.7.4