support qemu-riscv-virt platform

Signed-off-by: Axel Heider <axel.heider@hensoldt.net>

include/drivers/irq/riscv_plic0.h

@@ -4,15 +4,18 @@
  *
  * SPDX-License-Identifier: GPL-2.0-only
  *
- * SiFive U54/U74 PLIC handling (HiFive Unleashed/Unmatched, Polarfire)
+ * SiFive U54/U74 PLIC handling (HiFive Unleashed/Unmatched, Polarfire,
+ * QEMU RISC-V virt)
  */
 
 #pragma once
 
 /* This is a check that prevents using this driver blindly. Extend the list if
  * this driver is confirmed to be working on other platforms. */
-#if !defined(CONFIG_PLAT_HIFIVE) && !defined(CONFIG_PLAT_POLARFIRE)
-#error "This code supports the SiFive U54/U74 PLIC only."
+#if !defined(CONFIG_PLAT_HIFIVE) && \
+    !defined(CONFIG_PLAT_POLARFIRE) && \
+    !defined(CONFIG_PLAT_QEMU_RISCV_VIRT)
+#error "Check if this platform suppots a PLIC."
 #endif
 
 /* tell the kernel we have the set trigger feature */

libsel4/sel4_plat_include/qemu-riscv-virt/sel4/plat/api/constants.h

@@ -0,0 +1,11 @@
+/*
+ * Copyright 2022, HENSOLDT Cyber
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <autoconf.h>
+
+/* nothing here */

src/plat/qemu-riscv-virt/config.cmake

@@ -0,0 +1,103 @@
+#
+# Copyright 2022, HENSOLDT Cyber
+# Copyright 2020, Data61, CSIRO (ABN 41 687 119 230)
+#
+# SPDX-License-Identifier: GPL-2.0-only
+#
+
+cmake_minimum_required(VERSION 3.7.2)
+
+declare_platform(qemu-riscv-virt KernelPlatformQEMURiscVVirt PLAT_QEMU_RISCV_VIRT KernelArchRiscV)
+
+if(KernelPlatformQEMURiscVVirt)
+
+    if("${KernelSel4Arch}" STREQUAL riscv64)
+        declare_seL4_arch(riscv64)
+    elseif("${KernelSel4Arch}" STREQUAL riscv32)
+        # This is still untested
+        declare_seL4_arch(riscv32)
+    else()
+        fallback_declare_seL4_arch_default(riscv64)
+    endif()
+
+    config_set(KernelOpenSBIPlatform OPENSBI_PLATFORM "generic")
+    config_set(KernelPlatformFirstHartID FIRST_HART_ID 1)
+
+    set(QEMU_BINARY "qemu-system-${KernelSel4Arch}")
+    find_program(QEMU_BINARY ${QEMU_BINARY})
+
+    set(MIN_QEMU_VERSION "5.1.0")
+    execute_process(
+        COMMAND ${QEMU_BINARY} -version
+        OUTPUT_VARIABLE QEMU_VERSION_STR
+        RESULT_VARIABLE error
+    )
+    if(error)
+        message(FATAL_ERROR "Failed to determine qemu version (${QEMU_BINARY})")
+    endif()
+    string(
+        REGEX
+            MATCH
+            "[0-9](\\.[0-9])+"
+            QEMU_VERSION
+            ${QEMU_VERSION_STR}
+    )
+    if("${QEMU_VERSION}" VERSION_LESS "${MIN_QEMU_VERSION}")
+        message(FATAL_ERROR "Error: neev at least QEMU version ${MIN_QEMU_VERSION}")
+    endif()
+
+    set(QEMU_DT_BASE_NAME "${CMAKE_BINARY_DIR}/qemu-riscv-virt")
+    set(QEMU_DTB "${QEMU_DT_BASE_NAME}.dtb")
+    set(QEMU_DTS "${QEMU_DT_BASE_NAME}.dts")
+
+    if(KernelSel4ArchRiscV64)
+        set(QEMU_CPU "rv64")
+    elseif(KernelSel4ArchRiscV32)
+        set(QEMU_CPU "rv32")
+    else()
+        message(FATAL_ERROR "unknown RISC-V KernelSel4Arch '${KernelSel4Arch}'")
+    endif()
+
+    if("${QEMU_MEMORY}" STREQUAL "")
+        set(QEMU_MEMORY "1024")
+    endif()
+
+    if(KernelMaxNumNodes)
+        set(QEMU_SMP_OPTION "${KernelMaxNumNodes}")
+    else()
+        set(QEMU_SMP_OPTION "1")
+    endif()
+
+    execute_process(
+        COMMAND
+            ${QEMU_BINARY} -machine virt,dumpdtb=${QEMU_DTB} -cpu ${QEMU_CPU} -smp
+            ${QEMU_SMP_OPTION} -m ${QEMU_MEMORY} -nographic
+        ERROR_VARIABLE QEMU_OUTPUT_MESSAGE
+        RESULT_VARIABLE error
+    )
+    if(${QEMU_OUTPUT_MESSAGE})
+        string(STRIP ${QEMU_OUTPUT_MESSAGE} QEMU_OUTPUT_MESSAGE)
+    endif()
+    message(STATUS ${QEMU_OUTPUT_MESSAGE})
+    if(error)
+        message(FATAL_ERROR "Failed to dump DTB using ${QEMU_BINARY})")
+    endif()
+    execute_process(
+        COMMAND
+            dtc -q -I dtb -O dts -o ${QEMU_DTS} ${QEMU_DTB}
+        RESULT_VARIABLE error
+    )
+    if(error)
+        message(FATAL_ERROR "Failed to convert DTB to DTS (${QEMU_DTB})")
+    endif()
+
+    list(APPEND KernelDTSList "${QEMU_DTS}" "${CMAKE_CURRENT_LIST_DIR}/overlay-qemu-riscv-virt.dts")
+
+    # QEMU emulates SiFive PLIC/CLINT by default with a few interrupts, using
+    # 64 here seems a safe value. The 10 MHz timer clock is just a dummy value.
+    declare_default_headers(
+        TIMER_FREQUENCY 10000000 PLIC_MAX_NUM_INT 64
+        INTERRUPT_CONTROLLER drivers/irq/riscv_plic0.h
+    )
+
+endif()

src/plat/qemu-riscv-virt/overlay-qemu-riscv-virt.dts

@@ -0,0 +1,20 @@
+/*
+ * Copyright 2022, HENSOLDT Cyber
+ *
+ * SPDX-License-Identifier: GPL-2.0-only
+ */
+
+/ {
+    chosen {
+        /*
+         * - elfloader and kernel use SBI console by default
+         * - QEMU emulates a SiFive PLIC and CLINT by default
+         *
+         * Nothing needed for elfloader
+         *      seL4,elfloader-devices = ... ;
+         *
+         */
+        seL4,kernel-devices =
+            &{/soc/plic@c000000};
+    };
+};