Re: [PATCH V6 1/1] usb:serial: Add Fintek F81532/534 driver

From: Peter Hung
Date: Wed Nov 04 2015 - 03:19:47 EST


Hi

Oliver Neukum æ 2015/11/3 äå 06:03 åé:
On Tue, 2015-11-03 at 11:51 +0800, Peter Hung wrote:
+static int f81534_attach(struct usb_serial *serial)
+{
+ struct f81534_serial_private *serial_priv = NULL;
+ int status;
+ int i;
+ int offset;
+ uintptr_t setting_idx = (uintptr_t) usb_get_serial_data(serial);
+
+ serial_priv = kzalloc(sizeof(*serial_priv), GFP_KERNEL);
+ if (!serial_priv)
+ return -ENOMEM;
+
+ usb_set_serial_data(serial, serial_priv);
+ serial_priv->setting_idx = setting_idx;
+
+ for (i = 0; i < F81534_NUM_PORT; ++i) {
+ /* Disable all interrupt before submit URB */
+ status = f81534_setregister(serial->dev, i,
+ INTERRUPT_ENABLE_REGISTER, 0x00);
+ if (status) {
+ dev_err(&serial->dev->dev, "%s: IER disable failed\n",
+ __func__);
+ goto failed;
+ }
+ }
+
+ for (i = 0; i < F81534_NUM_PORT; ++i)
+ atomic_set(&serial_priv->port_active[i], 0);

Should be ATOMIC_INIT()


ATOMIC_INIT() seems to be used only for variable initializer, It cant be
used for dynamic allocation. Should I change it to a normal boolean
flag protecting with spin_lock ?


+static int f81534_port_remove(struct usb_serial_port *port)
+{
+ struct f81534_port_private *port_priv;
+
+ f81534_release_gpio(port);
+ port_priv = usb_get_serial_port_data(port);
+ kfree(port_priv);
+ return 0;
+}
+
+static void f81534_compare_msr(struct usb_serial_port *port, u8 *msr,

Is the point of passing a pointer to msr locking?

+ bool is_port_open)

This function is used only with URB callback function. The *msr is
reported by H/W with newest MSR. The USB-Serial generic system will
re-submit read URB when callback complete. So this function should
run once on the same time.

+static int f81534_tiocmget(struct tty_struct *tty)
+{
+ struct usb_serial_port *port = tty->driver_data;
+ struct f81534_port_private *port_priv = usb_get_serial_port_data(port);
+ unsigned long flags;
+ int r;
+ u8 msr, mcr;
+
+ /*
+ * We'll avoid to direct read MSR register. The IC will read the MSR
+ * changed and report it f81534_process_per_serial_block() by
+ * F81534_TOKEN_MSR_CHANGE.
+ *
+ * When this device in heavy loading (e.g., BurnInTest Loopback Test)
+ * The report of MSR register will delay received a bit. It's due to
+ * MSR interrupt is lowest priority in 16550A. So we decide to sleep
+ * a little time to pass the test.
+ */
+ if (schedule_timeout_interruptible(
+ msecs_to_jiffies(F81534_DELAY_READ_MSR))) {
+ dev_info(&port->dev, "%s: breaked !!\n", __func__);
+ }

Is the delay necessary or isn't it?
If it is necessary you should do something about the signal.


We add this delay due to stress test (Loop-back & 921600bps with
BurnInTest). It'll receive MSR with some delay when connecting with
DTR-DSR & RTS/CTS, but the delay smaller than 10ms. So we decided to
delay some time to pass the test.

+static int f81534_prepare_write_buffer(struct usb_serial_port *port,
+ void *dest, size_t size)
+{
+ unsigned char *ptr = (unsigned char *) dest;
+ struct f81534_port_private *port_priv = usb_get_serial_port_data(port);
+ int port_num = port_priv->phy;
+ struct usb_serial *serial = port->serial;
+
+ WARN_ON(size != serial->port[0]->bulk_out_size);
+
+ if (size != F81534_WRITE_BUFFER_SIZE) {
+ WARN_ON(size != F81534_WRITE_BUFFER_SIZE);

What is the sense of this?


I'll remove the double-check section with next version patch.


+ ptr[F81534_RECEIVE_BLOCK_SIZE * 0] = 0;
+ ptr[F81534_RECEIVE_BLOCK_SIZE * 1] = 1;
+ ptr[F81534_RECEIVE_BLOCK_SIZE * 2] = 2;
+ ptr[F81534_RECEIVE_BLOCK_SIZE * 3] = 3;

Either these ...

+ ptr[F81534_RECEIVE_BLOCK_SIZE * port_num + 0] = port_num;

.. or that is redundant


I'll remove it too.

Thanks for your advice.
--
With Best Regards,
Peter Hung
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