Documentation/mainboard: Add emulation/spike-riscv.md

Move the usage instructions from their ad-hoc place in Kconfig.name to
the Documentation directory, and expand them a bit.

Change-Id: Id6c7bbca40a21ecba00cab736af2f2662a985106
Signed-off-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net>
Reviewed-on: https://review.coreboot.org/28874
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Patrick Rudolph <siro@das-labor.org>
Reviewed-by: Philipp Hug <philipp@hug.cx>

2 files changed, 29 insertions, 0 deletions

diff --git a/Documentation/mainboard/emulation/spike-riscv.md b/Documentation/mainboard/emulation/spike-riscv.md
new file mode 100644
index 0000000000..55e87d9cc9
--- /dev/null
+++ b/Documentation/mainboard/emulation/spike-riscv.md
@@ -0,0 +1,23 @@
+# Spike RISC-V emulator
+
+[Spike], also known as riscv-isa-sim, is a commonly used [RISC-V] emulator.
+
+
+## Installation
+
+- Download `riscv-fesvr` and `riscv-isa-sim` from <https://github.com/riscv/>
+- Apply the two patches in <https://github.com/riscv/riscv-isa-sim/pull/53>,
+  which are necessary in order to have a serial console
+- Compile `riscv-fesvr` and then `riscv-isa-sim`
+
+
+## Building coreboot and running it in Spike
+
+- Configure coreboot and run `make` as usual
+- Run `util/riscv/make-spike-elf.sh build/coreboot.rom build/coreboot.elf` to
+  convert coreboot to an ELF that Spike can load
+- Run `spike -m1024 build/coreboot.elf`
+
+
+[Spike]: https://github.com/riscv/riscv-isa-sim
+[RISC-V]: https://riscv.org/
diff --git a/Documentation/mainboard/index.md b/Documentation/mainboard/index.md
index c346a3b8f0..c1e5262a98 100644
--- a/Documentation/mainboard/index.md
+++ b/Documentation/mainboard/index.md
@@ -10,6 +10,12 @@ This section contains documentation about coreboot on specific mainboards.
 
 - [CN81XX EVB SFF](cavium/cn8100_sff_evb.md)
 
+## Emulation
+
+The boards in this section are not real mainboards, but emulators.
+
+- [Spike RISC-V emulator](emulation/spike-riscv.md)
+
 ## Foxconn
 
 - [D41S](foxconn/d41s.md)