Re: [PATCH v11 10/10] tty: serial: Add Nuvoton ma35d1 serial driver support

[Jacky Huang]

Dear Jiri,

Thanks for your advice.

On 2023/5/24 下午 03:42, Jiri Slaby wrote:
> On 16. 05. 23, 9:52, Jacky Huang wrote:
> > +static void ma35d1serial_config_port(struct uart_port *port, int flags)
> > +{
> > +    /*
> > +     * Driver core for serial ports forces a non-zero value for port 
> > type.
> > +     * Write an arbitrary value here to accommodate the serial core 
> > driver,
> > +     * as ID part of UAPI is redundant.
> > +     */
> > +    port->type = 1;
>
> So this 1 translates to PORT_8250. Why not to use it directly? Or 
> something more saner like PORT_16550A?
It's not actually 8250 or 16550A.
Can we add the following definition to 
'include/uapi/linux/serial_core.h' and use PORT_MA35 instead?

#define PORT_MA35    124


> > +}
> > +
> > +static int ma35d1serial_verify_port(struct uart_port *port, struct 
> > serial_struct *ser)
> > +{
> > +    if (port->type != PORT_UNKNOWN && ser->type != 1)
> > +        return -EINVAL;
> > +
> > +    return 0;
> > +}
> ...
> > +static int __init ma35d1serial_console_setup(struct console *co, 
> > char *options)
> > +{
> > +    struct device_node *np = ma35d1serial_uart_nodes[co->index];
> > +    struct uart_ma35d1_port *p = &ma35d1serial_ports[co->index];
> > +    u32 val32[4];
> > +    struct uart_port *port;
> > +    int baud = 115200;
> > +    int bits = 8;
> > +    int parity = 'n';
> > +    int flow = 'n';
> > +
> > +    /*
> > +     * Check whether an invalid uart number has been specified, and
>
> You dereferenced ma35d1serial_uart_nodes already. Doesn't 
> console=ttyNVT1000 (or something like that) crash the system?

I will add the following check before np = 
"ma35d1serial_uart_nodes[co->index]".

if (co->index < 0 || co->index >= MA35_UART_NR)
    return -EINVAL;


> > +     * if so, search for the first available port that does have
> > +     * console support.
>
> The code below doesn't match this comment.

Yes, I will remove the above comment.

> > +     */
> > +    if ((co->index < 0) || (co->index >= MA35_UART_NR)) {
> > +        pr_debug("Console Port%x out of range\n", co->index);
> > +        return -EINVAL;
> > +    }
> > +
> > +    if (of_property_read_u32_array(np, "reg", val32, 4) != 0)
>
> Shouldn't that 4 be ARRAY_SIZE(val32) instead?

Will be fixed.

> > +        return -EINVAL;
>
> One \n here please.

Okay, I will add it.

> > +    p->port.iobase = val32[1];
> > +    p->port.membase = ioremap(p->port.iobase, MA35_UART_REG_SIZE);
>
> What if this fails?

I will add a check for the return value.

> > +    p->port.ops = &ma35d1serial_ops;
> > +    p->port.line = 0;
> > +    p->port.uartclk = MA35_UART_CONSOLE_CLK;
> > +
> > +    port = &ma35d1serial_ports[co->index].port;
>
> Isn't this:
>   port = &p->port;
> ?
>
> Either use port on all above lines or drop the "port" variable 
> completely and use "p->port" below instead.

I will remove port variable and use p->port only.

> > +
> > +    if (options)
> > +        uart_parse_options(options, &baud, &parity, &bits, &flow);
> > +
> > +    return uart_set_options(port, co, baud, parity, bits, flow);
> > +}
> > +
> > +static struct console ma35d1serial_console = {
> > +    .name    = "ttyNVT",
> > +    .write   = ma35d1serial_console_write,
> > +    .device  = uart_console_device,
> > +    .setup   = ma35d1serial_console_setup,
> > +    .flags   = CON_PRINTBUFFER | CON_ENABLED,
> > +    .index   = -1,
> > +    .data    = &ma35d1serial_reg,
>
> I don't see console->data used anywhere in the driver?

I will remove it.

> > +};
> ...
> > +static int ma35d1serial_probe(struct platform_device *pdev)
> > +{
> > +    struct resource *res_mem;
> > +    struct uart_ma35d1_port *up;
> > +    int ret = 0;
> > +
> > +    if (pdev->dev.of_node) {
> > +        ret = of_alias_get_id(pdev->dev.of_node, "serial");
> > +        if (ret < 0) {
> > +            dev_err(&pdev->dev, "failed to get alias/pdev id, errno 
> > %d\n", ret);
> > +            return ret;
> > +        }
> > +    }
> > +    up = &ma35d1serial_ports[ret];
> > +    up->port.line = ret;
> > +    res_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> > +    if (!res_mem)
> > +        return -ENODEV;
> > +
> > +    up->port.iobase = res_mem->start;
> > +    up->port.membase = ioremap(up->port.iobase, MA35_UART_REG_SIZE);
>
> Check this too.

Okay, sure.

> > +    up->port.ops = &ma35d1serial_ops;
> > +
> > +    spin_lock_init(&up->port.lock);
> > +
> > +    up->clk = of_clk_get(pdev->dev.of_node, 0);
> > +    if (IS_ERR(up->clk)) {
> > +        ret = PTR_ERR(up->clk);
> > +        dev_err(&pdev->dev, "failed to get core clk: %d\n", ret);
> > +        goto err_iounmap;
> > +    }
> > +
> > +    ret = clk_prepare_enable(up->clk);
> > +    if (ret)
> > +        goto err_iounmap;
> > +
> > +    if (up->port.line != 0)
> > +        up->port.uartclk = clk_get_rate(up->clk);
> > +
> > +    ret = platform_get_irq(pdev, 0);
> > +    if (ret < 0)
> > +        goto err_clk_disable;
> > +
> > +    up->port.irq = ret;
> > +    up->port.dev = &pdev->dev;
> > +    up->port.flags = UPF_BOOT_AUTOCONF;
> > +
> > +    platform_set_drvdata(pdev, up);
> > +
> > +    ret = uart_add_one_port(&ma35d1serial_reg, &up->port);
> > +    if (ret < 0)
> > +        goto err_free_irq;
> > +
> > +    return 0;
> > +
> > +err_free_irq:
> > +    free_irq(up->port.irq, &up->port);
> > +
> > +err_clk_disable:
> > +    clk_disable_unprepare(up->clk);
> > +
> > +err_iounmap:
> > +    iounmap(up->port.membase);
> > +    return ret;
> > +}
>
> thanks,

Best regards,
Jacky Huang