[qemu] Create and attach flash device for SPI Host 0/SPI Device

Depends on lowRISC/qemu#255

Signed-off-by: Alice Ziuziakowska <[email protected]>

Author: ziuziakowska

rules/opentitan/qemu.bzl

@@ -431,6 +431,10 @@ def _test_dispatch(ctx, exec_env, firmware):
         }
         param["bootstrap_cmd"] = '--exec="no-op" # SKIPPING BOOTSTRAP'
 
+    # Attach SPI flash to SPI Host 0/SPI Device bus. Chosen model is W25Q256 (32MiB)
+    qemu_args += ["-global", "ot-earlgrey-board.spiflash0=w25q256"]
+    qemu_args += ["-drive", "if=mtd,file=spiflash0.bin,format=raw,bus=0"]
+
     # Get the pre-test_cmd args.
     args = get_fallback(ctx, "attr.args", exec_env)
     args = " ".join(args).format(**param)

rules/scripts/qemu_test.sh

@@ -18,6 +18,7 @@ args=( __args__ )
 
 mutable_flash="flash_img.bin"
 mutable_otp="otp_img.raw"
+spiflash0="spiflash0.bin"
 
 test_args=( "$@" )
 qemu_test_args=()
@@ -52,6 +53,7 @@ cleanup() {
     wait "$qemu_pid"
 
     rm -f "${mutable_otp}" "${mutable_flash}"
+    rm -f "${spiflash0}"
     rm -f qemu-monitor qemu.log
 }
 trap cleanup EXIT
@@ -63,6 +65,9 @@ if [ -n "${flash}" ]; then
     cp "${flash}" "${mutable_flash}" && chmod +w "${mutable_flash}"
 fi
 
+# create backing storage for flash device on SPI Host 0/SPI Device SPI bus
+dd if=/dev/zero of="${spiflash0}" bs=1M count=32 status=none && chmod +w "${spiflash0}"
+
 # QEMU disconnects from `stdout` when it daemonizes so we need to stream
 # the log through a pipe:
 mkfifo qemu.log && cat qemu.log &