diff options
| -rw-r--r-- | drivers/acpi/scan.c | 74 |
1 files changed, 74 insertions, 0 deletions
diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c index 5f28cf778349..cfc73fecaba4 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); +/* + * The UART device described by the SPCR table is the only object which needs + * special-casing. Everything else is covered by ACPI namespace paths 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; } +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) || res.start != spcr_uart_addr) + return false; + + acpi_handle_info(handle, "The UART device @%pa in SPCR table will be 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 = ACPI_BUS_TYPE_DEVICE; status = 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; } +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 +1994,20 @@ 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. |