Messages in this thread | | | Date | Tue, 15 Dec 2015 12:40:37 +0000 | From | Vladimir Murzin <> | Subject | Re: [PATCH v1 04/10] serial: mps2-uart: add MPS2 UART driver |
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On 12/12/15 23:39, Andy Shevchenko wrote: > On Wed, Dec 2, 2015 at 11:33 AM, Vladimir Murzin > <vladimir.murzin@arm.com> wrote: >> This driver adds support to the UART controller found on ARM MPS2 >> platform. > > Just few comments (have neither time not big desire to do full review). >
Still better than nothing ;) I'm mostly agree on points you had, so I've just left some I'm doubt about...
>> + >> +static void mps2_uart_enable_ms(struct uart_port *port) >> +{ >> +} >> + >> +static void mps2_uart_break_ctl(struct uart_port *port, int ctl) >> +{ >> +} > > Are those required to be present? If not, remove them until you have > alive code there.
A quick grep shows that core calls mps2_uart_break_ctl() unconditionally, but, yes, it checks for presence of mps2_uart_enable_ms() before jumping there, so it is safe to remove latter.
>> +static irqreturn_t mps2_uart_oerrirq(int irq, void *data) >> +{ >> + irqreturn_t handled = IRQ_NONE; >> + struct uart_port *port = data; >> + u8 irqflag = mps2_uart_read8(port, UARTn_INT); >> + >> + spin_lock(&port->lock); >> + >> + if (irqflag & UARTn_INT_RX_OVERRUN) { >> + struct tty_port *tport = &port->state->port; >> + >> + mps2_uart_write8(port, UARTn_INT_RX_OVERRUN, UARTn_INT); >> + tty_insert_flip_char(tport, 0, TTY_OVERRUN); >> + port->icount.overrun++; >> + handled = IRQ_HANDLED; >> + } >> + >> + /* XXX: this shouldn't happen? */ > > If shouldn't why it's there? Otherwise better to explain which > conditions may lead to this. >
In practice I've never seen that happened and I think it never *should* happen since we check if there is room in TX buffer. However, I could be wrong here, so it is why that statement has question mark.
>> + if (irqflag & UARTn_INT_TX_OVERRUN) { >> + mps2_uart_write8(port, UARTn_INT_TX_OVERRUN, UARTn_INT); >> + handled = IRQ_HANDLED; >> + } >> + >> + spin_unlock(&port->lock); >> + >> + return handled; >> +} >> + ... >> +static void mps2_uart_release_port(struct uart_port *port) >> +{ >> +} >> + >> +static int mps2_uart_request_port(struct uart_port *port) >> +{ >> + return 0; >> +} >> + > > Same question about empty stubs.
Looks like they called unconditionally by the core.
>> +static int __init mps2_uart_init(void) >> +{ >> + int ret; >> + >> + ret = uart_register_driver(&mps2_uart_driver); >> + if (ret) >> + return ret; >> + >> + ret = platform_driver_register(&mps2_serial_driver); >> + if (ret) >> + uart_unregister_driver(&mps2_uart_driver); >> + >> + pr_info("MPS2 UART driver initialized\n"); >> + >> + return ret; >> +} >> +module_init(mps2_uart_init); >> + >> +static void __exit mps2_uart_exit(void) >> +{ >> + platform_driver_unregister(&mps2_serial_driver); >> + uart_unregister_driver(&mps2_uart_driver); >> +} >> +module_exit(mps2_uart_exit); > > module_platform_driver(); > And move uart_*register calls to probe/remove. >
With this move we'll get uart_*register for every device probed, no?
Thanks Vladimir
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