Re: [Xen-devel] [PATCH V2 21/33] xen/arm: Use device tree API in pl011 UART driver

[Ian Campbell <Ian.Campbell@xxxxxxxxxx>]

On Wed, 2013-05-08 at 03:33 +0100, Julien Grall wrote:
> @@ -227,32 +239,56 @@ static struct uart_driver __read_mostly pl011_driver = {
>      .tx_ready     = pl011_tx_ready,
>      .putc         = pl011_putc,
>      .getc         = pl011_getc,
> -    .irq          = pl011_irq
> +    .irq          = pl011_irq,
> +    .dt_irq_get   = pl011_dt_irq,
>  };
>  
> -/* TODO: Parse UART config from device-tree or command-line */
> -
> -void __init pl011_init(int index, unsigned long register_base_address)
> +/* TODO: Parse UART config from the command line */
> +static int __init pl011_uart_init(struct dt_device_node *dev,
> +                                  const void *data)
>  {
> +    const struct serial_arm_defaults *defaults = data;
>      struct pl011 *uart;
> +    int res;
>  
> -    if ( (index < 0) || (index > 1) )
> -        return;
> +    if ( (defaults->index < 0) || (defaults->index > 1) )
> +        return -EINVAL;
>  
> -    uart = &pl011_com[index];
> +    uart = &pl011_com[defaults->index];
>  
>      uart->clock_hz  = 0x16e3600;
>      uart->baud      = 38400;
>      uart->data_bits = 8;
>      uart->parity    = PARITY_NONE;
>      uart->stop_bits = 1;
> -    uart->irq       = 37; /* TODO Need to find this from devicetree */
> -    uart->regs      = (uint32_t *) register_base_address;
> +    uart->regs      = (uint32_t *) defaults->register_base_address;

Should this not come from struct dt_device_node?

Perhaps the driver needs to be instantiating its own FIXMAP mapping
instead of doing it in common code? In fact can we not get rid of the
fixmap for the runtime (not early) console and use the ioremap stuff
which Stefano just enabled with his vmap patches, or the early_ioremap
stuff if necessary.

That does then call into question the whole serial_arm_defaults thing.
Perhaps index should just be the order in which they are registered (and
at the moment it is effectively hardcoded to 0 anyway)

> +
> +    res = dt_device_get_irq(dev, 0, &uart->irq);
> +    if ( res )
> +    {
> +        early_printk("pl011: Unable to retrieve the IRQ\n");
> +        return res;
> +    }
>  
>      /* Register with generic serial driver. */
>      serial_register_uart(uart - pl011_com, &pl011_driver, uart);
> +
> +    dt_device_set_used_by(dev, DT_USED_BY_XEN);
> +
> +    return 0;
>  }

Ian.



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