On 2021/7/2 17:58, Andy Shevchenko wrote:
On Fri, Jul 02, 2021 at 04:46:47PM +0800, Jie Deng wrote:
Add an I2C bus driver for virtio para-virtualization.
The controller can be emulated by the backend driver in
any device model software by following the virtio protocol.
The device specification can be found on
https://lists.oasis-open.org/archives/virtio-comment/202101/msg00008.html.
By following the specification, people may implement different
backend drivers to emulate different controllers according to
their needs.
...
+static int virtio_i2c_complete_reqs(struct virtqueue *vq,
+ struct virtio_i2c_req *reqs,
+ struct i2c_msg *msgs, int nr,
+ bool fail)
+{
+ struct virtio_i2c_req *req;
+ bool failed = fail;
+ unsigned int len;
+ int i, j = 0;
+
+ for (i = 0; i < nr; i++) {
+ /* Detach the ith request from the vq */
+ req = virtqueue_get_buf(vq, &len);
+
+ /*
+ * Condition (req && req == &reqs[i]) should always meet since
+ * we have total nr requests in the vq.
+ */
+ if (!failed && (WARN_ON(!(req && req == &reqs[i])) ||
+ (req->in_hdr.status != VIRTIO_I2C_MSG_OK)))
+ failed = true;
...and after failed is true, we are continuing the loop, why?
Still need to continue to do some cleanup.
+ i2c_put_dma_safe_msg_buf(reqs[i].buf, &msgs[i], !failed);
+ if (!failed)
+ ++j;
Besides better to read j++ the j itself can be renamed to something more
verbose.
Will change it to j++.
+ }
+ return (fail ? -ETIMEDOUT : j);
Redundant parentheses.
Will remove the parentheses.
+}
...
+ ret = virtio_i2c_send_reqs(vq, reqs, msgs, num);
+ if (ret != num) {
+ virtio_i2c_complete_reqs(vq, reqs, msgs, ret, true);
Below you check the returned code, here is not.
I will do some optimization here.
+ ret = 0;
+ goto err_free;
+ }
+
+ reinit_completion(&vi->completion);
+ virtqueue_kick(vq);
+
+ time_left = wait_for_completion_timeout(&vi->completion, adap->timeout);
+ if (!time_left)
+ dev_err(&adap->dev, "virtio i2c backend timeout.\n");
+
+ ret = virtio_i2c_complete_reqs(vq, reqs, msgs, num, !time_left);
+
+err_free:
+ kfree(reqs);
+ return ret;
+++ b/include/uapi/linux/virtio_i2c.h
+#include <linux/types.h>
+
+/* The bit 0 of the @virtio_i2c_out_hdr.@flags, used to group the requests */
+#define VIRTIO_I2C_FLAGS_FAIL_NEXT BIT(0)
It's _BITUL() or so from linux/const.h.
https://elixir.bootlin.com/linux/latest/source/include/uapi/linux/const.h#L28
You may not use internal definitions in UAPI headers.
Let's use this _BITUL() from linux/const.h instead. Thank you !
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