vpl: Add Kconfig options for VPL

Add VPL versions of commonly used Kconfig options.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/serial/Kconfig b/drivers/serial/Kconfig
index 1e595d0..5dcf5c0 100644
--- a/drivers/serial/Kconfig
+++ b/drivers/serial/Kconfig
@@ -74,6 +74,16 @@
 	  This option enables the full UART in TPL, so if is it disabled,
 	  the full UART driver will be omitted, thus saving space.
 
+config VPL_SERIAL_PRESENT
+	bool "Provide a serial driver in VPL"
+	depends on DM_SERIAL && VPL
+	default y
+	help
+	  In very space-constrained devices even the full UART driver is too
+	  large. In this case the debug UART can still be used in some cases.
+	  This option enables the full UART in TPL, so if is it disabled,
+	  the full UART driver will be omitted, thus saving space.
+
 # Logic to allow us to use the imply keyword to set what the default port
 # should be.  The default is otherwise 1.
 config CONS_INDEX_0
@@ -195,6 +205,16 @@
 	  implements serial_putc() etc. The uclass interface is
 	  defined in include/serial.h.
 
+config VPL_DM_SERIAL
+	bool "Enable Driver Model for serial drivers in VPL"
+	depends on DM_SERIAL
+	default y if VPL && DM_SERIAL
+	help
+	  Enable driver model for serial in VPL. This replaces
+	  drivers/serial/serial.c with the serial uclass, which
+	  implements serial_putc() etc. The uclass interface is
+	  defined in include/serial.h.
+
 config DEBUG_UART
 	bool "Enable an early debug UART for debugging"
 	help