Re: [PATCH 4/5] i3c: slave: func: add tty driver

From: Jiri Slaby
Date: Thu Oct 19 2023 - 03:21:47 EST


On 18. 10. 23, 23:58, Frank Li wrote:
Add tty over I3C slave function driver.

Many of the master review comments apply also here. Please fix here too. More below.

--- /dev/null
+++ b/drivers/i3c/func/tty.c
@@ -0,0 +1,548 @@
...
+static void i3c_slave_tty_rx_complete(struct i3c_request *req)
+{
+ struct ttyi3c_port *port = req->context;
+
+ if (req->status == I3C_REQUEST_CANCEL) {
+ i3c_slave_ctrl_free_request(req);
+ return;
+ }
+
+ for (int i = 0; i < req->actual; i++)
+ tty_insert_flip_char(&port->port, *(u8 *)(req->buf + i), 0);

Maybe I miss something obvious, but req->buf is void *. So why not simple tty_insert_flip_string()?


+ sport->buffer = (void *)get_zeroed_page(GFP_KERNEL);
+ if (!sport->buffer)
+ return -ENOMEM;
+
+ sport->xmit.buf = (void *)get_zeroed_page(GFP_KERNEL);

tty_port_alloc_xmit_buf()


+static int i3c_tty_probe(struct i3c_slave_func *func)
+{
+ struct device *dev = &func->dev;
+ struct ttyi3c_port *port;
+
+ port = devm_kzalloc(dev, sizeof(*port), GFP_KERNEL);
+ if (!port)
+ return -ENOMEM;
+
+ port->i3cdev = func;
+ dev_set_drvdata(&func->dev, port);
+
+ port->workqueue = alloc_workqueue("%s", 0, 0, dev_name(&func->dev));

Another wq? You'd have to have a strong reason for these. Drop that.

+ if (!port->workqueue)
+ return -ENOMEM;
+
+ INIT_WORK(&port->work, i3c_slave_tty_i3c_work);
+
+ return 0;
+}
+
+static void i3c_tty_remove(struct i3c_slave_func *func)
+{
+ struct ttyi3c_port *port;
+
+ port = dev_get_drvdata(&func->dev);

That can be on one line.

+
+ destroy_workqueue(port->workqueue);
+}


+static int i3c_open(struct tty_struct *tty, struct file *filp)
+{
+ struct ttyi3c_port *sport = tty->driver_data;
+ int ret;
+
+ if (!i3c_slave_ctrl_get_addr(sport->i3cdev->ctrl)) {
+ dev_info(&sport->i3cdev->dev, "No slave addr assigned, try hotjoin");

Should this be a debug print instead?

+ ret = i3c_slave_ctrl_hotjoin(sport->i3cdev->ctrl);
+ if (ret) {
+ dev_err(&sport->i3cdev->dev, "Hotjoin failure, check connection");
+ return ret;
+ }
+ }
+
+ return tty_port_open(&sport->port, tty, filp);

regards,
--
js
suse labs