1 files changed, 125 insertions, 0 deletions
diff --git a/drivers/hwtracing/stm/dummy_stm.c b/drivers/hwtracing/stm/dummy_stm.c
new file mode 100644
index 0000000000..38528ffdc0
--- /dev/null
+++ b/drivers/hwtracing/stm/dummy_stm.c
@@ -0,0 +1,125 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * A dummy STM device for stm/stm_source class testing.
+ * Copyright (c) 2014, Intel Corporation.
+ *
+ * STM class implements generic infrastructure for  System Trace Module devices
+ * as defined in MIPI STPv2 specification.
+ */
+
+#undef DEBUG
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/stm.h>
+#include <uapi/linux/stm.h>
+
+static ssize_t notrace
+dummy_stm_packet(struct stm_data *stm_data, unsigned int master,
+		 unsigned int channel, unsigned int packet, unsigned int flags,
+		 unsigned int size, const unsigned char *payload)
+{
+#ifdef DEBUG
+	u64 pl = 0;
+
+	if (payload)
+		pl = *(u64 *)payload;
+
+	if (size < 8)
+		pl &= (1ull << (size * 8)) - 1;
+	trace_printk("[%u:%u] [pkt: %x/%x] (%llx)\n", master, channel,
+		     packet, size, pl);
+#endif
+	return size;
+}
+
+#define DUMMY_STM_MAX 32
+
+static struct stm_data dummy_stm[DUMMY_STM_MAX];
+
+static int nr_dummies = 4;
+
+module_param(nr_dummies, int, 0400);
+
+static unsigned int fail_mode;
+
+module_param(fail_mode, int, 0600);
+
+static unsigned int master_min;
+
+module_param(master_min, int, 0400);
+
+static unsigned int master_max = STP_MASTER_MAX;
+
+module_param(master_max, int, 0400);
+
+static unsigned int nr_channels = STP_CHANNEL_MAX;
+
+module_param(nr_channels, int, 0400);
+
+static int dummy_stm_link(struct stm_data *data, unsigned int master,
+			  unsigned int channel)
+{
+	if (fail_mode && (channel & fail_mode))
+		return -EINVAL;
+
+	return 0;
+}
+
+static int dummy_stm_init(void)
+{
+	int i, ret = -ENOMEM;
+
+	if (nr_dummies < 0 || nr_dummies > DUMMY_STM_MAX)
+		return -EINVAL;
+
+	if (master_min > master_max ||
+	    master_max > STP_MASTER_MAX ||
+	    nr_channels > STP_CHANNEL_MAX)
+		return -EINVAL;
+
+	for (i = 0; i < nr_dummies; i++) {
+		dummy_stm[i].name = kasprintf(GFP_KERNEL, "dummy_stm.%d", i);
+		if (!dummy_stm[i].name)
+			goto fail_unregister;
+
+		dummy_stm[i].sw_start		= master_min;
+		dummy_stm[i].sw_end		= master_max;
+		dummy_stm[i].sw_nchannels	= nr_channels;
+		dummy_stm[i].packet		= dummy_stm_packet;
+		dummy_stm[i].link		= dummy_stm_link;
+
+		ret = stm_register_device(NULL, &dummy_stm[i], THIS_MODULE);
+		if (ret)
+			goto fail_free;
+	}
+
+	return 0;
+
+fail_unregister:
+	for (i--; i >= 0; i--) {
+		stm_unregister_device(&dummy_stm[i]);
+fail_free:
+		kfree(dummy_stm[i].name);
+	}
+
+	return ret;
+
+}
+
+static void dummy_stm_exit(void)
+{
+	int i;
+
+	for (i = 0; i < nr_dummies; i++) {
+		stm_unregister_device(&dummy_stm[i]);
+		kfree(dummy_stm[i].name);
+	}
+}
+
+module_init(dummy_stm_init);
+module_exit(dummy_stm_exit);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("dummy_stm device");
+MODULE_AUTHOR("Alexander Shishkin <alexander.shishkin@linux.intel.com>");