arm/acpi: Add a new ACPI initialized function for UART

This adds a new function to initialize UART for ACPI on ARM.

Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org>
Reviewed-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>

xen/arch/arm/setup.c

@@ -768,7 +768,7 @@ void __init start_xen(unsigned long boot_phys_offset,
 
     gic_preinit();
 
-    dt_uart_init();
+    arm_uart_init();
     console_init_preirq();
     console_init_ring();
 

xen/drivers/char/arm-uart.c

@@ -1,7 +1,7 @@
 /*
  * xen/drivers/char/arm-uart.c
  *
- * Generic uart retrieved via the device tree
+ * Generic uart retrieved via the device tree or ACPI
  *
  * Julien Grall <julien.grall@linaro.org>
  * Copyright (c) 2013 Linaro Limited.
@@ -23,6 +23,7 @@
 #include <xen/device_tree.h>
 #include <xen/serial.h>
 #include <xen/errno.h>
+#include <xen/acpi.h>
 
 /*
  * Configure UART port with a string:
@@ -35,7 +36,7 @@
 static char __initdata opt_dtuart[256] = "";
 string_param("dtuart", opt_dtuart);
 
-void __init dt_uart_init(void)
+static void __init dt_uart_init(void)
 {
     struct dt_device_node *dev;
     int ret;
@@ -96,6 +97,38 @@ void __init dt_uart_init(void)
         printk("Unable to initialize dtuart: %d\n", ret);
 }
 
+#ifdef CONFIG_ACPI
+static void __init acpi_uart_init(void)
+{
+    struct acpi_table_spcr *spcr = NULL;
+    int ret;
+
+    acpi_get_table(ACPI_SIG_SPCR, 0, (struct acpi_table_header **)&spcr);
+
+    if ( spcr == NULL )
+    {
+        printk("Unable to get spcr table\n");
+    }
+    else
+    {
+        ret = acpi_device_init(DEVICE_SERIAL, NULL, spcr->interface_type);
+
+        if ( ret )
+            printk("Unable to initialize acpi uart: %d\n", ret);
+    }
+}
+#else
+static void __init acpi_uart_init(void) { }
+#endif
+
+void __init arm_uart_init(void)
+{
+    if ( acpi_disabled )
+        dt_uart_init();
+    else
+        acpi_uart_init();
+}
+
 /*
  * Local variables:
  * mode: C

xen/include/xen/serial.h

@@ -170,7 +170,7 @@ struct ns16550_defaults {
 void ns16550_init(int index, struct ns16550_defaults *defaults);
 void ehci_dbgp_init(void);
 
-void __init dt_uart_init(void);
+void arm_uart_init(void);
 
 struct physdev_dbgp_op;
 int dbgp_op(const struct physdev_dbgp_op *);