Merge tag 'for-linus-4.8-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git...

[sfrench/cifs-2.6.git] / drivers / acpi / scan.c

diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index 405056b95b05b34a29b9d90c283032d11614047a..ad9fc84a8601206cec6cc1fb15cb36e5c23250cb 100644 (file)
--- 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;
@@ -1458,6 +1465,41 @@ 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)
 {
@@ -1471,6 +1513,9 @@ 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))
@@ -1925,11 +1970,26 @@ 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");
+}
+
 static bool acpi_scan_initialized;
 
 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();
@@ -1945,6 +2005,20 @@ 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.