[PATCH v4 6/6] cxl/test: Add cxl_test accelerator driver

[Dave Jiang <dave.jiang@intel.com>]

Add a type2 accelerator mock driver for the platform device that
simulates a CXL type2 device. The driver exercises the same
minimal API calls that a real CXL type2 driver would utilize.

Signed-off-by: Dave Jiang <dave.jiang@intel.com>
---
v4:
- Use pdev->id instead of pdev->dev->id. (sashiko)
---
 tools/testing/cxl/test/Kbuild  |  2 ++
 tools/testing/cxl/test/accel.c | 66 ++++++++++++++++++++++++++++++++++
 2 files changed, 68 insertions(+)
 create mode 100644 tools/testing/cxl/test/accel.c

diff --git a/tools/testing/cxl/test/Kbuild b/tools/testing/cxl/test/Kbuild
index c168e3c998a7..9a24ddc28488 100644
--- a/tools/testing/cxl/test/Kbuild
+++ b/tools/testing/cxl/test/Kbuild
@@ -5,10 +5,12 @@ obj-m += cxl_test.o
 obj-m += cxl_mock.o
 obj-m += cxl_mock_mem.o
 obj-m += cxl_translate.o
+obj-m += cxl_mock_accel.o
 
 cxl_test-y := cxl.o
 cxl_test-y += hmem_test.o
 cxl_mock-y := mock.o
 cxl_mock_mem-y := mem.o
+cxl_mock_accel-y := accel.o
 
 KBUILD_CFLAGS := $(filter-out -Wmissing-prototypes -Wmissing-declarations, $(KBUILD_CFLAGS))
diff --git a/tools/testing/cxl/test/accel.c b/tools/testing/cxl/test/accel.c
new file mode 100644
index 000000000000..9c8235f9d97b
--- /dev/null
+++ b/tools/testing/cxl/test/accel.c
@@ -0,0 +1,66 @@
+// SPDX-License-Identifier: GPL-2.0-only
+// Copyright(c) 2026 Intel Corporation. All rights reserved.
+
+#include <linux/platform_device.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/sizes.h>
+#include <cxl/mailbox.h>
+#include <cxlmem.h>
+
+struct mock_cxl_accel {
+	struct cxl_dev_state cxlds;
+	struct cxl_memdev *cxlmd;
+};
+
+static int cxl_mock_accel_probe(struct platform_device *pdev)
+{
+	struct mock_cxl_accel *cxl_accel;
+	struct device *dev = &pdev->dev;
+	struct cxl_dev_state *cxlds;
+	struct cxl_memdev *cxlmd;
+	struct range mock_range;
+	int rc;
+
+	cxl_accel = devm_cxl_dev_state_create(&pdev->dev, CXL_DEVTYPE_DEVMEM,
+					      pdev->id + 1, 0,
+					      struct mock_cxl_accel, cxlds,
+					      false);
+	if (!cxl_accel)
+		return -ENOMEM;
+
+	cxlds = &cxl_accel->cxlds;
+	cxlds->media_ready = true;
+	rc = cxl_set_capacity(cxlds, SZ_512M);
+	if (rc)
+		return rc;
+
+	cxlmd = devm_cxl_probe_mem(cxlds, &mock_range);
+	if (IS_ERR(cxlmd))
+		return PTR_ERR(cxlmd);
+	cxl_accel->cxlmd = cxlmd;
+
+	dev_dbg(dev, "Probed mock accelerator with range %pra\n", &mock_range);
+
+	return 0;
+}
+
+static const struct platform_device_id cxl_mock_accel_ids[] = {
+	{ .name = "cxl_type2_accel", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(platform, cxl_mock_accel_ids);
+
+static struct platform_driver cxl_mock_accel_driver = {
+	.probe = cxl_mock_accel_probe,
+	.id_table = cxl_mock_accel_ids,
+	.driver = {
+		.name = KBUILD_MODNAME,
+		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
+	},
+};
+
+module_platform_driver(cxl_mock_accel_driver);
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("cxl_test: accelerator device mock module");
+MODULE_IMPORT_NS("CXL");
-- 
2.54.0