From: "Rafael J. Wysocki" <rafael@kernel.org>
To: Shannon Zhao <zhaoshenglong@huawei.com>
Cc: "devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
sstabellini@kernel.org, "Rafael J. Wysocki" <rjw@rjwysocki.net>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will.deacon@arm.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
xen-devel@lists.xen.org,
"open list:ACPI" <linux-acpi@vger.kernel.org>,
julien.grall@arm.com, linux-efi@vger.kernel.org,
stefano.stabellini@citrix.com, david.vrabel@citrix.com,
peter.huangpeng@huawei.com, Len Brown <lenb@kernel.org>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
Shannon Zhao <shannon.zhao@linaro.org>
Subject: Re: [PATCH v9 01/17] Xen: ACPI: Hide UART used by Xen
Date: Thu, 31 Mar 2016 14:02:47 +0200 [thread overview]
Message-ID: <CAJZ5v0iSDk1u47jhed9TyEef1D=nERMfBw8AzcquTgH9g=Yqpg__46851.8279413276$1459425852$gmane$org@mail.gmail.com> (raw)
In-Reply-To: <1459423425-1220-2-git-send-email-zhaoshenglong@huawei.com>
On Thu, Mar 31, 2016 at 1:23 PM, Shannon Zhao <zhaoshenglong@huawei.com> wrote:
> From: Shannon Zhao <shannon.zhao@linaro.org>
>
> 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@rjwysocki.net> (supporter:ACPI)
> CC: Len Brown <lenb@kernel.org> (supporter:ACPI)
> CC: linux-acpi@vger.kernel.org (open list:ACPI)
> Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org>
> ---
> drivers/acpi/scan.c | 69 +++++++++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 69 insertions(+)
>
> diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
> index 5f28cf7..29f26fc 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);
> +static u64 spcr_uart_addr;
>
> struct acpi_dep_data {
> struct list_head node;
> @@ -1453,6 +1454,42 @@ 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 != 0) {
Why not to write this as
if (spcr_uart_addr) {
Or even
if (!spcr_uart_addr)
return false;
and then the indentation level of the rest will be reduced.
> + if (!acpi_has_method(handle, METHOD_NAME__CRS))
> + return false;
> +
I'd like to see a comment here that the devices in question are
assumed to have only one memory resource present which is why we only
look for the first one.
> + 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) {
> + printk(KERN_INFO PREFIX "The UART device @%pa in SPCR table will be hidden\n",
> + &res.start);
> + return true;
> + }
> + }
> +
> + return false;
> +}
> +
Thanks,
Rafael
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next prev parent reply other threads:[~2016-03-31 12:02 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-31 11:23 [PATCH v9 00/17] Add ACPI support for Xen Dom0 on ARM64 Shannon Zhao
2016-03-31 11:23 ` [PATCH v9 01/17] Xen: ACPI: Hide UART used by Xen Shannon Zhao
2016-03-31 11:23 ` [PATCH v9 02/17] xen/grant-table: Move xlated_setup_gnttab_pages to common place Shannon Zhao
2016-03-31 11:23 ` [PATCH v9 03/17] Xen: xlate: Use page_to_xen_pfn instead of page_to_pfn Shannon Zhao
2016-03-31 11:23 ` [PATCH v9 04/17] arm/xen: Use xen_xlate_map_ballooned_pages to setup grant table Shannon Zhao
2016-03-31 11:23 ` [PATCH v9 05/17] xen: memory : Add new XENMAPSPACE type XENMAPSPACE_dev_mmio Shannon Zhao
2016-03-31 11:23 ` [PATCH v9 06/17] Xen: ARM: Add support for mapping platform device mmio Shannon Zhao
2016-03-31 11:23 ` [PATCH v9 07/17] Xen: ARM: Add support for mapping AMBA " Shannon Zhao
2016-03-31 11:23 ` [PATCH v9 08/17] Xen: public/hvm: sync changes of HVM_PARAM_CALLBACK_VIA ABI from Xen Shannon Zhao
2016-03-31 11:23 ` [PATCH v9 09/17] xen/hvm/params: Add a new delivery type for event-channel in HVM_PARAM_CALLBACK_IRQ Shannon Zhao
2016-03-31 11:23 ` [PATCH v9 10/17] arm/xen: Get event-channel irq through HVM_PARAM when booting with ACPI Shannon Zhao
2016-03-31 11:23 ` [PATCH v9 11/17] ARM: XEN: Move xen_early_init() before efi_init() Shannon Zhao
2016-03-31 11:23 ` [PATCH v9 12/17] ARM64: ACPI: Check if it runs on Xen to enable or disable ACPI Shannon Zhao
2016-03-31 11:23 ` [PATCH v9 13/17] ARM: Xen: Document UEFI support on Xen ARM virtual platforms Shannon Zhao
2016-03-31 11:23 ` [PATCH v9 14/17] XEN: EFI: Move x86 specific codes to architecture directory Shannon Zhao
2016-03-31 11:23 ` [PATCH v9 15/17] ARM64: XEN: Add a function to initialize Xen specific UEFI runtime services Shannon Zhao
2016-03-31 11:23 ` [PATCH v9 16/17] FDT: Add a helper to get the subnode by given name Shannon Zhao
2016-03-31 11:23 ` [PATCH v9 17/17] Xen: EFI: Parse DT parameters for Xen specific UEFI Shannon Zhao
[not found] ` <1459423425-1220-2-git-send-email-zhaoshenglong@huawei.com>
2016-03-31 12:02 ` Rafael J. Wysocki [this message]
-- strict thread matches above, loose matches on Subject: below --
2016-03-29 8:05 [PATCH v9 01/17] Xen: ACPI: Hide UART used by Xen Shannon Zhao
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