On Fri, Apr 1, 2016 at 5:48 PM, Shannon Zhao <shannon.zhao@xxxxxxxxxx> wrote:
> ACPI 6.0 introduces a new table STAO to list the devices which are used
> by Xen and can't be used by Dom0. On Xen virtual platforms, the physical
> UART is used by Xen. So here it hides UART from Dom0.
>
> CC: "Rafael J. Wysocki" <rjw@xxxxxxxxxxxxx> (supporter:ACPI)
> CC: Len Brown <lenb@xxxxxxxxxx> (supporter:ACPI)
> CC: linux-acpi@xxxxxxxxxxxxxxx (open list:ACPI)
> Signed-off-by: Shannon Zhao <shannon.zhao@xxxxxxxxxx>
> ---
> drivers/acpi/scan.c | 71 +++++++++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 71 insertions(+)
>
> diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
> index 5f28cf7..4d2d9eb 100644
> --- a/drivers/acpi/scan.c
> +++ b/drivers/acpi/scan.c
> @@ -45,6 +45,7 @@ static LIST_HEAD(acpi_scan_handlers_list);
> DEFINE_MUTEX(acpi_device_lock);
> LIST_HEAD(acpi_wakeup_device_list);
> static DEFINE_MUTEX(acpi_hp_context_lock);
A comment here would be useful explaining that the below is an
exceptional thing an nothing like it is expected to be needed if
foreseeable future.
> +static u64 spcr_uart_addr;
>
> struct acpi_dep_data {
> struct list_head node;
> @@ -1453,6 +1454,44 @@ static int acpi_add_single_object(struct acpi_device **child,
> return 0;
> }
>
> +static acpi_status acpi_get_resource_memory(struct acpi_resource *ares,
> + void *context)
> +{
> + struct resource *res = context;
> +
> + if (acpi_dev_resource_memory(ares, res))
> + return AE_CTRL_TERMINATE;
> +
> + return AE_OK;
> +}
> +
> +static bool acpi_device_should_be_hidden(acpi_handle handle)
> +{
> + acpi_status status;
> + struct resource res;
> +
> + /* Check if it should ignore the UART device */
> + if (!(spcr_uart_addr && acpi_has_method(handle, METHOD_NAME__CRS)))
> + return false;
> +
> + /*
> + * The UART device described in SPCR table is assumed to have only one
> + * memory resource present. So we only look for the first one here.
> + */
> + status = acpi_walk_resources(handle, METHOD_NAME__CRS,
> + acpi_get_resource_memory, &res);
> + if (ACPI_FAILURE(status))
> + return false;
> +
> + if (res.start == spcr_uart_addr) {
What about restructuring that a bit.
if (ACPI_FAILURE(status) || res.start != spcr_uart_addr)
return false;
> + printk(KERN_INFO PREFIX "The UART device @%pa in SPCR table will be hidden\n",
> + &res.start);
And maybe use acpi_handle_info() for this message?
Thanks,
Rafael
--
To unsubscribe from this list: send the line "unsubscribe devicetree" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
