From mboxrd@z Thu Jan 1 00:00:00 1970 From: Shannon Zhao Subject: Re: [PATCH v11 01/17] Xen: ACPI: Hide UART used by Xen Date: Fri, 15 Apr 2016 14:43:37 +0800 Message-ID: <57108D99.5030800@huawei.com> References: <1460030614-16112-1-git-send-email-zhaoshenglong@huawei.com> <1460030614-16112-2-git-send-email-zhaoshenglong@huawei.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <1460030614-16112-2-git-send-email-zhaoshenglong-hv44wF8Li93QT0dZR+AlfA@public.gmane.org> Sender: linux-efi-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, sstabellini-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, "Rafael J. Wysocki" Cc: catalin.marinas-5wv7dgnIgG8@public.gmane.org, will.deacon-5wv7dgnIgG8@public.gmane.org, julien.grall-5wv7dgnIgG8@public.gmane.org, david.vrabel-Sxgqhf6Nn4DQT0dZR+AlfA@public.gmane.org, xen-devel-GuqFBffKawuEi8DpZVb4nw@public.gmane.org, devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-efi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, shannon.zhao-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org, peter.huangpeng-hv44wF8Li93QT0dZR+AlfA@public.gmane.org, Len Brown , ACPI List-Id: linux-acpi@vger.kernel.org Hi Rafael=EF=BC=8C Could you please give your comments on this patch? Thanks in advanced! On 2016/4/7 20:03, Shannon Zhao wrote: > From: Shannon Zhao >=20 > ACPI 6.0 introduces a new table STAO to list the devices which are us= ed > by Xen and can't be used by Dom0. On Xen virtual platforms, the physi= cal > UART is used by Xen. So here it hides UART from Dom0. >=20 > CC: "Rafael J. Wysocki" (supporter:ACPI) > CC: Len Brown (supporter:ACPI) > CC: linux-acpi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org (open list:ACPI) > Signed-off-by: Shannon Zhao > --- > drivers/acpi/scan.c | 74 +++++++++++++++++++++++++++++++++++++++++++= ++++++++++ > 1 file changed, 74 insertions(+) >=20 > diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c > index 5f28cf7..cfc73fe 100644 > --- a/drivers/acpi/scan.c > +++ b/drivers/acpi/scan.c > @@ -46,6 +46,13 @@ DEFINE_MUTEX(acpi_device_lock); > LIST_HEAD(acpi_wakeup_device_list); > static DEFINE_MUTEX(acpi_hp_context_lock); > =20 > +/* > + * The UART device described by the SPCR table is the only object wh= ich needs > + * special-casing. Everything else is covered by ACPI namespace path= s in STAO > + * table. > + */ > +static u64 spcr_uart_addr; > + > struct acpi_dep_data { > struct list_head node; > acpi_handle master; > @@ -1453,6 +1460,41 @@ static int acpi_add_single_object(struct acpi_= device **child, > return 0; > } > =20 > +static acpi_status acpi_get_resource_memory(struct acpi_resource *ar= es, > + void *context) > +{ > + struct resource *res =3D 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 =3D acpi_walk_resources(handle, METHOD_NAME__CRS, > + acpi_get_resource_memory, &res); > + if (ACPI_FAILURE(status) || res.start !=3D spcr_uart_addr) > + return false; > + > + acpi_handle_info(handle, "The UART device @%pa in SPCR table will b= e hidden\n", > + &res.start); > + > + return true; > +} > + > static int acpi_bus_type_and_status(acpi_handle handle, int *type, > unsigned long long *sta) > { > @@ -1466,6 +1508,9 @@ static int acpi_bus_type_and_status(acpi_handle= handle, int *type, > switch (acpi_type) { > case ACPI_TYPE_ANY: /* for ACPI_ROOT_OBJECT */ > case ACPI_TYPE_DEVICE: > + if (acpi_device_should_be_hidden(handle)) > + return -ENODEV; > + > *type =3D ACPI_BUS_TYPE_DEVICE; > status =3D acpi_bus_get_status_handle(handle, sta); > if (ACPI_FAILURE(status)) > @@ -1916,9 +1961,24 @@ static int acpi_bus_scan_fixed(void) > return result < 0 ? result : 0; > } > =20 > +static void __init acpi_get_spcr_uart_addr(void) > +{ > + acpi_status status; > + struct acpi_table_spcr *spcr_ptr; > + > + status =3D acpi_get_table(ACPI_SIG_SPCR, 0, > + (struct acpi_table_header **)&spcr_ptr); > + if (ACPI_SUCCESS(status)) > + spcr_uart_addr =3D spcr_ptr->serial_port.address; > + else > + printk(KERN_WARNING PREFIX "STAO table present, but SPCR is missin= g\n"); > +} > + > int __init acpi_scan_init(void) > { > int result; > + acpi_status status; > + struct acpi_table_stao *stao_ptr; > =20 > acpi_pci_root_init(); > acpi_pci_link_init(); > @@ -1934,6 +1994,20 @@ int __init acpi_scan_init(void) > =20 > acpi_scan_add_handler(&generic_device_handler); > =20 > + /* > + * If there is STAO table, check whether it needs to ignore the UAR= T > + * device in SPCR table. > + */ > + status =3D acpi_get_table(ACPI_SIG_STAO, 0, > + (struct acpi_table_header **)&stao_ptr); > + if (ACPI_SUCCESS(status)) { > + if (stao_ptr->header.length > sizeof(struct acpi_table_stao)) > + printk(KERN_INFO PREFIX "STAO Name List not yet supported."); > + > + if (stao_ptr->ignore_uart) > + acpi_get_spcr_uart_addr(); > + } > + > mutex_lock(&acpi_scan_lock); > /* > * Enumerate devices in the ACPI namespace. >=20 --=20 Shannon