remoteproc: Add AVM WASP driver

Some AVM Fritzbox router boards (3390, 3490, 5490, 5491, 7490),
that are Lantiq XRX200 based, have a memory only ATH79 based
WASP (Wireless Assistant Support Processor) SoC that has wifi
cards connected to it. It does not share anything with the
Lantiq host and has no persistent storage. It has an mdio based
connection for bringing up a small network boot firmware and is
connected to the Lantiq GSWIP switch via gigabit ethernet. This
is used to load an initramfs linux image to it, after the
network boot firmware was started.

In order to initialize this remote processor we need to:
- power on the SoC using startup gpio
- reset the SoC using the reset gpio
- send the network boot firmware using mdio
- send the linux image using raw ethernet frames

This driver allows to start and stop the WASP SoC.

Signed-off-by: Daniel Kestrel <kestrelseventyfour@gmail.com>

drivers/remoteproc/Kconfig

@@ -23,6 +23,16 @@ config REMOTEPROC_CDEV
 
 	  It's safe to say N if you don't want to use this interface.
 
+config AVM_WASP_REMOTEPROC
+	tristate "AVM WASP remoteproc support"
+	depends on NET_DSA_LANTIQ_GSWIP
+	help
+	  Say y here to support booting the secondary SoC ATH79 target
+	  called Wireless Assistant Support Processor (WASP) that some
+	  AVM Fritzbox devices (3390, 3490, 5490, 5491, 7490) have built in.
+
+	  It's safe to say N here.
+
 config IMX_REMOTEPROC
 	tristate "i.MX remoteproc support"
 	depends on ARCH_MXC

drivers/remoteproc/Makefile

@@ -11,6 +11,7 @@ remoteproc-y				+= remoteproc_sysfs.o
 remoteproc-y				+= remoteproc_virtio.o
 remoteproc-y				+= remoteproc_elf_loader.o
 obj-$(CONFIG_REMOTEPROC_CDEV)		+= remoteproc_cdev.o
+obj-$(CONFIG_AVM_WASP_REMOTEPROC)	+= avm_wasp.o
 obj-$(CONFIG_IMX_REMOTEPROC)		+= imx_rproc.o
 obj-$(CONFIG_IMX_DSP_REMOTEPROC)	+= imx_dsp_rproc.o
 obj-$(CONFIG_INGENIC_VPU_RPROC)		+= ingenic_rproc.o