linux-kernel - Re: [PATCH v2 2/2] serial: 8250_dw: add ACPI support for uart on Hisilicon Hip05 soc

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Date:	Thu, 30 Jun 2016 12:38:37 +0300
From:	Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To:	Kefeng Wang <wangkefeng.wang@...wei.com>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:	Jiri Slaby <jslaby@...e.com>, linux-serial@...r.kernel.org,
	linux-kernel@...r.kernel.org, z.liuxinliang@...ilicon.com,
	guohanjun@...wei.com, linux-acpi@...r.kernel.org,
	xuwei5@...ilicon.com, graeme.gregory@...aro.org
Subject: Re: [PATCH v2 2/2] serial: 8250_dw: add ACPI support for uart on
 Hisilicon Hip05 soc

On Thu, 2016-06-30 at 09:27 +0800, Kefeng Wang wrote:
> Add ACPI identifier for UART on Hisilicon Hip05 soc, be careful
> that it is not 16550 compatibal.
> 
> Meanwhile, set dw8250_serial_out32 to keep consistent between
> serial_out
> and serial_in in ACPI.
> 
> Signed-off-by: Kefeng Wang <wangkefeng.wang@...wei.com>
> ---
>  drivers/tty/serial/8250/8250_dw.c | 13 +++++++++++--
>  1 file changed, 11 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/tty/serial/8250/8250_dw.c
> b/drivers/tty/serial/8250/8250_dw.c
> index 65f3da7..096431b 100644
> --- a/drivers/tty/serial/8250/8250_dw.c
> +++ b/drivers/tty/serial/8250/8250_dw.c
> @@ -272,6 +272,12 @@ static bool dw8250_idma_filter(struct dma_chan
> *chan, void *param)
>  	return param == chan->device->dev->parent;
>  }
>  
> +/* non 16550 compatible id list*/
> +static const struct acpi_device_id non_16550_id_list[] = {
> +	{ "HISI0031", 0 },
> +	{ },
> +};
> +

On first glance it looks redundant, see below.

>  static void dw8250_quirks(struct uart_port *p, struct dw8250_data
> *data)
>  {
>  	if (p->dev->of_node) {
> @@ -301,8 +307,10 @@ static void dw8250_quirks(struct uart_port *p,
> struct dw8250_data *data)
>  		p->iotype = UPIO_MEM32;
>  		p->regshift = 2;
>  		p->serial_in = dw8250_serial_in32;
> -		/* So far none of there implement the Busy
> Functionality */
> -		data->uart_16550_compatible = true;
> +		p->serial_out = dw8250_serial_out32;
> +
> +		if (!acpi_match_device(non_16550_id_list, p->dev))
> +			data->uart_16550_compatible = true;
>  	}
>  
>  	/* Platforms with iDMA */
> @@ -618,6 +626,7 @@ static const struct acpi_device_id
> dw8250_acpi_match[] = {
>  	{ "APMC0D08", 0},
>  	{ "AMD0020", 0 },
>  	{ "AMDI0020", 0 },
> +	{ "HISI0031", 0 },

So, we may put something instead of 0 here and consider it as a set of
special quirks / setup instructions / etc.

struct dw8250_dev_info {
  unsigned int  uart_16550_compatible:1;
};

static const struct dw8250_dev_info hisi_dev_info = {
  .uart_16550_compatible = 1,
}

...
 { "HISI0031", (kernel_ulong_t)&hisi_dev_info },
...

And so on.

>  	{ },
>  };
>  MODULE_DEVICE_TABLE(acpi, dw8250_acpi_match);

-- 

Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Intel Finland Oy