virtio-mmio: Devices parameter parsing

This patch adds an option to instantiate guest virtio-mmio devices
basing on a kernel command line (or module) parameter, for example:

	virtio_mmio.devices=0x100@0x100b0000:48

Signed-off-by: Pawel Moll <pawel.moll@arm.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

1 files changed, 17 insertions, 0 deletions

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index c1601e5a8b71..8b350512f360 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -110,6 +110,7 @@ parameter is applicable:
         USB     USB support is enabled.
         USBHID  USB Human Interface Device support is enabled.
         V4L     Video For Linux support is enabled.
+        VMMIO   Driver for memory mapped virtio devices is enabled.
         VGA     The VGA console has been enabled.
         VT      Virtual terminal support is enabled.
         WDT     Watchdog support is enabled.
@@ -2847,6 +2848,22 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
         video=          [FB] Frame buffer configuration
                         See Documentation/fb/modedb.txt.
 
+        virtio_mmio.device=
+                        [VMMIO] Memory mapped virtio (platform) device.
+
+                                <size>@<baseaddr>:<irq>[:<id>]
+                        where:
+                                <size>     := size (can use standard suffixes
+                                                like K, M and G)
+                                <baseaddr> := physical base address
+                                <irq>      := interrupt number (as passed to
+                                                request_irq())
+                                <id>       := (optional) platform device id
+                        example:
+                                virtio_mmio.device=1K@0x100b0000:48:7
+
+                        Can be used multiple times for multiple devices.
+
         vga=            [BOOT,X86-32] Select a particular video mode
                         See Documentation/x86/boot.txt and
                         Documentation/svga.txt.