Update doc

README.md

@@ -535,6 +535,17 @@ mm_malloc: Allocated 0x80046ac0, size 848
 nx_start: CPU0: Beginning Idle Loop
 ```
 
+_How does it work?_
+
+At NuttX Startup: [board_app_initialize](https://github.com/lupyuen2/wip-pinephone-nuttx/blob/tinyemu/boards/risc-v/qemu-rv/rv-virt/src/qemu_rv_appinit.c#L77-L123) calls...
+
+- [qemu_virtio_register_mmio_devices](https://github.com/lupyuen2/wip-pinephone-nuttx/blob/tinyemu/boards/risc-v/qemu-rv/rv-virt/src/qemu_rv_appinit.c#L54-L73) (to register all VirtIO MMIO Devices) which calls...
+
+- [virtio_register_mmio_device](https://github.com/lupyuen2/wip-pinephone-nuttx/blob/tinyemu/drivers/virtio/virtio-mmio.c#L809-L932) 
+(to register a VirtIO MMIO Device, explained below)
+
+Let's create a VirtIO Queue for the VirtIO Console and send some data...
+
 # Test TinyEMU VirtIO Console with NuttX
 
 Earlier we saw NuttX creating a VirtIO Queue for VirtIO Console: [virtio_serial_init](https://github.com/apache/nuttx/blob/master/drivers/virtio/virtio-serial.c#L445-L511) calls...
@@ -640,11 +651,12 @@ NuttX VirtIO Driver is based on OpenAMP with MMIO...
 
 - [NuttX VirtIO Framework and Future Works](https://www.youtube.com/watch?v=CYMkAv-WjQg)
 
-At NuttX Startup: [board_app_initialize](https://github.com/apache/nuttx/blob/master/boards/risc-v/qemu-rv/rv-virt/src/qemu_rv_appinit.c#L76-L121) calls...
+At NuttX Startup: [board_app_initialize](https://github.com/lupyuen2/wip-pinephone-nuttx/blob/tinyemu/boards/risc-v/qemu-rv/rv-virt/src/qemu_rv_appinit.c#L77-L123) calls...
 
-- [qemu_virtio_register_mmio_devices](https://github.com/apache/nuttx/blob/master/boards/risc-v/qemu-rv/rv-virt/src/qemu_rv_appinit.c#L53-L72) which calls...
+- [qemu_virtio_register_mmio_devices](https://github.com/lupyuen2/wip-pinephone-nuttx/blob/tinyemu/boards/risc-v/qemu-rv/rv-virt/src/qemu_rv_appinit.c#L54-L73) (to register all VirtIO MMIO Devices) which calls...
 
-- [virtio_register_mmio_device](https://github.com/apache/nuttx/blob/master/drivers/virtio/virtio-mmio.c#L809-L880) which calls...
+- [virtio_register_mmio_device](https://github.com/lupyuen2/wip-pinephone-nuttx/blob/tinyemu/drivers/virtio/virtio-mmio.c#L809-L932) 
+(to register a VirtIO MMIO Device) which calls...
 
 - [virtio_mmio_init_device](https://github.com/apache/nuttx/blob/master/drivers/virtio/virtio-mmio.c#L740-L805) which passes...