Message ID | 1459423425-1220-2-git-send-email-zhaoshenglong@huawei.com (mailing list archive) |
---|---|
State | Superseded, archived |
Headers | show |
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 -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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) { + if (!acpi_has_method(handle, METHOD_NAME__CRS)) + return false; + + 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; +} + static int acpi_bus_type_and_status(acpi_handle handle, int *type, unsigned long long *sta) { @@ -1466,6 +1503,9 @@ 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 = ACPI_BUS_TYPE_DEVICE; status = acpi_bus_get_status_handle(handle, sta); if (ACPI_FAILURE(status)) @@ -1916,9 +1956,24 @@ static int acpi_bus_scan_fixed(void) return result < 0 ? result : 0; } +static void __init acpi_get_spcr_uart_addr(void) +{ + acpi_status status; + struct acpi_table_spcr *spcr_ptr; + + status = acpi_get_table(ACPI_SIG_SPCR, 0, + (struct acpi_table_header **)&spcr_ptr); + if (ACPI_SUCCESS(status)) + spcr_uart_addr = spcr_ptr->serial_port.address; + else + printk(KERN_WARNING PREFIX "STAO table present, but SPCR is missing\n"); +} + int __init acpi_scan_init(void) { int result; + acpi_status status; + struct acpi_table_stao *stao_ptr; acpi_pci_root_init(); acpi_pci_link_init(); @@ -1934,6 +1989,20 @@ int __init acpi_scan_init(void) acpi_scan_add_handler(&generic_device_handler); + /* + * If there is STAO table, check whether it needs to ignore the UART + * device in SPCR table. + */ + status = 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.