Re: [Xen-devel] [PATCH 01/13] Xen : Hide UART used by Xen

[Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>]

CC'ing ACPI maintainers.

Please use ./scripts/get_maintainer.pl to retrieve a list of maintainers
to CC for each patch.


On Tue, 17 Nov 2015, shannon.zhao@xxxxxxxxxx wrote:
> From: Shannon Zhao <shannon.zhao@xxxxxxxxxx>
> 
> According to the STAO table, hide UART used by Xen from Dom0.
> 
> Signed-off-by: Shannon Zhao <shannon.zhao@xxxxxxxxxx>
> ---
>  drivers/acpi/bus.c | 22 ++++++++++++++++++++++
>  1 file changed, 22 insertions(+)
> 
> diff --git a/drivers/acpi/bus.c b/drivers/acpi/bus.c
> index a212cef..e93806b 100644
> --- a/drivers/acpi/bus.c
> +++ b/drivers/acpi/bus.c
> @@ -46,6 +46,7 @@ ACPI_MODULE_NAME("bus");
>  struct acpi_device *acpi_root;
>  struct proc_dir_entry *acpi_root_dir;
>  EXPORT_SYMBOL(acpi_root_dir);
> +static u64 uart_addr;

I would call this spcr_addr or spcr_uart_addr because there are many
uarts on the system but only one spcr. It might make sense to initialize
this to 0xffffffffffffffff rather than 0, which could actually be a
correct uart address.


>  #ifdef CONFIG_X86
>  #ifdef CONFIG_ACPI_CUSTOM_DSDT
> @@ -93,6 +94,16 @@ acpi_status acpi_bus_get_status_handle(acpi_handle handle,
>  {
>       acpi_status status;
>
> +     if (uart_addr) {
> +             u64 addr;
> +             status = acpi_evaluate_integer(handle, METHOD_NAME__ADR, NULL,
> +                                            &addr);
> +             if (ACPI_SUCCESS(status) && (addr == uart_addr)) {
> +                     *sta = 0;
> +                     return AE_OK;
> +             }
> +     }
> +
>       status = acpi_evaluate_integer(handle, "_STA", NULL, sta);
>       if (ACPI_SUCCESS(status))
>               return AE_OK;
> @@ -1069,6 +1080,7 @@ EXPORT_SYMBOL_GPL(acpi_kobj);
>  static int __init acpi_init(void)
>  {
>       int result;
> +     struct acpi_table_stao *stao_ptr;
>  
>       if (acpi_disabled) {
>               printk(KERN_INFO PREFIX "Interpreter disabled.\n");
> @@ -1081,6 +1093,16 @@ static int __init acpi_init(void)
>               acpi_kobj = NULL;
>       }
>  
> +     acpi_get_table(ACPI_SIG_STAO, 1,
> +                    (struct acpi_table_header **)&stao_ptr);
> +     if(stao_ptr->ignore_uart)
> +     {

Please follow the linux coding style. You can use
./scripts/checkpatch.pl to check for coding style errors.


> +             struct acpi_table_spcr *spcr_ptr;
> +             acpi_get_table(ACPI_SIG_SPCR, 1,
> +                            (struct acpi_table_header **)&spcr_ptr);
> +             uart_addr = spcr_ptr->serial_port.address;
> +     }
> +
>       init_acpi_device_notify();
>       result = acpi_bus_init();
>       if (result) {
> -- 
> 2.1.0
> 

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