[PATCH v2 6/6] tests/qtest: Add qtest for Milk-V Duo board

[Kuan-Wei Chiu <visitorckw@gmail.com>]

Add minimal qtest coverage for the Milk-V Duo machine to validate basic
MMIO mapping and register access.

Currently tested:
- Verify DW8250 UART component version and type signatures.
- Test read/write access to CV1800B clock bypass register.

Tested with:
$ meson test -C build -v qemu:qtest-riscv64/milkv-duo-test
[...]
Ok:                 1
Fail:               0

Signed-off-by: Kuan-Wei Chiu <visitorckw@gmail.com>
---
 MAINTAINERS                  |  1 +
 tests/qtest/meson.build      |  3 +-
 tests/qtest/milkv-duo-test.c | 70 ++++++++++++++++++++++++++++++++++++
 3 files changed, 73 insertions(+), 1 deletion(-)
 create mode 100644 tests/qtest/milkv-duo-test.c

diff --git a/MAINTAINERS b/MAINTAINERS
index a5649fd31f..8e62809728 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1790,6 +1790,7 @@ F: hw/riscv/milkv_duo.c
 F: include/hw/char/dw8250.h
 F: include/hw/misc/cv1800b_clk.h
 F: include/hw/riscv/cv1800b.h
+F: tests/qtest/milkv-duo-test.c
 
 RX Machines
 -----------
diff --git a/tests/qtest/meson.build b/tests/qtest/meson.build
index 43f83ffd3a..524340276e 100644
--- a/tests/qtest/meson.build
+++ b/tests/qtest/meson.build
@@ -290,7 +290,8 @@ qtests_riscv64 = ['riscv-csr-test'] + \
   (unpack_edk2_blobs ? ['bios-tables-test'] : []) + \
   (config_all_devices.has_key('CONFIG_IOMMU_TESTDEV') and
    config_all_devices.has_key('CONFIG_RISCV_IOMMU') ?
-   ['iommu-riscv-test'] : [])
+   ['iommu-riscv-test'] : []) + \
+   ['milkv-duo-test']
 
 qos_test_ss = ss.source_set()
 qos_test_ss.add(
diff --git a/tests/qtest/milkv-duo-test.c b/tests/qtest/milkv-duo-test.c
new file mode 100644
index 0000000000..06064b8733
--- /dev/null
+++ b/tests/qtest/milkv-duo-test.c
@@ -0,0 +1,70 @@
+/*
+ * QTest for Milk-V Duo Board
+ *
+ * Copyright (c) 2026 Kuan-Wei Chiu <visitorckw@gmail.com>
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include "qemu/osdep.h"
+#include "libqtest.h"
+
+#define CV1800B_CLK_BASE            0x03002000
+#define CV1800B_CLK_BYPASS          0x030
+#define CV1800B_CLK_BYPASS_RESET    0xFFFFFFFF
+#define TEST_PATTERN_5A             0x5A5A5A5A
+#define TEST_PATTERN_A5             0xA5A5A5A5
+
+#define CV1800B_UART0_BASE          0x04140000
+#define DW_UART_UCV                 0xF8
+#define DW_UART_CTR                 0xFC
+#define DW_UART_VERSION_3_23A       0x3332332A
+#define DW_UART_TYPE_SIGNATURE      0x44570110
+
+static void test_milkv_duo_uart(void)
+{
+    QTestState *qts;
+    uint32_t component_version;
+    uint32_t component_type;
+
+    qts = qtest_init("-M milkv-duo");
+
+    component_version = qtest_readl(qts, CV1800B_UART0_BASE + DW_UART_UCV);
+    g_assert_cmphex(component_version, ==, DW_UART_VERSION_3_23A);
+
+    component_type = qtest_readl(qts, CV1800B_UART0_BASE + DW_UART_CTR);
+    g_assert_cmphex(component_type, ==, DW_UART_TYPE_SIGNATURE);
+
+    qtest_quit(qts);
+}
+
+static void test_milkv_duo_clk(void)
+{
+    QTestState *qts;
+    uint32_t clk_bypass_val;
+
+    qts = qtest_init("-M milkv-duo");
+
+    clk_bypass_val = qtest_readl(qts, CV1800B_CLK_BASE + CV1800B_CLK_BYPASS);
+    g_assert_cmphex(clk_bypass_val, ==, CV1800B_CLK_BYPASS_RESET);
+
+    qtest_writel(qts, CV1800B_CLK_BASE + CV1800B_CLK_BYPASS, TEST_PATTERN_5A);
+    clk_bypass_val = qtest_readl(qts, CV1800B_CLK_BASE + CV1800B_CLK_BYPASS);
+    g_assert_cmphex(clk_bypass_val, ==, TEST_PATTERN_5A);
+
+    qtest_writel(qts, CV1800B_CLK_BASE + CV1800B_CLK_BYPASS, TEST_PATTERN_A5);
+    clk_bypass_val = qtest_readl(qts, CV1800B_CLK_BASE + CV1800B_CLK_BYPASS);
+    g_assert_cmphex(clk_bypass_val, ==, TEST_PATTERN_A5);
+
+    qtest_quit(qts);
+}
+
+int main(int argc, char **argv)
+{
+    g_test_init(&argc, &argv, NULL);
+
+    qtest_add_func("/riscv/milkv-duo/uart", test_milkv_duo_uart);
+    qtest_add_func("/riscv/milkv-duo/clk", test_milkv_duo_clk);
+
+    return g_test_run();
+}
-- 
2.54.0.563.g4f69b47b94-goog