[PATCH 05/11] rvtrace: Add trace encoder driver

[Anup Patel <apatel@ventanamicro.com>]

From: Mayuresh Chitale <mchitale@ventanamicro.com>

Add initial implementation of RISC-V trace encoder driver. The encoder
is defined in the RISC-V Trace Control Interface specification.

Co-developed-by: Anup Patel <apatel@ventanamicro.com>
Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Signed-off-by: Mayuresh Chitale <mchitale@ventanamicro.com>
---
 drivers/hwtracing/rvtrace/Kconfig           |   7 ++
 drivers/hwtracing/rvtrace/Makefile          |   1 +
 drivers/hwtracing/rvtrace/rvtrace-encoder.c | 107 ++++++++++++++++++++
 3 files changed, 115 insertions(+)
 create mode 100644 drivers/hwtracing/rvtrace/rvtrace-encoder.c

diff --git a/drivers/hwtracing/rvtrace/Kconfig b/drivers/hwtracing/rvtrace/Kconfig
index f8f6feea1953..ba35c05f3f54 100644
--- a/drivers/hwtracing/rvtrace/Kconfig
+++ b/drivers/hwtracing/rvtrace/Kconfig
@@ -14,3 +14,10 @@ menuconfig RVTRACE
 
 	  To compile this driver as a module, choose M here: the module
 	  will be called rvtrace.
+
+config RVTRACE_ENCODER
+	tristate "RISC-V Trace Encoder driver"
+	depends on RVTRACE
+	default y
+	help
+	  This driver provides support for RISC-V Trace Encoder component.
diff --git a/drivers/hwtracing/rvtrace/Makefile b/drivers/hwtracing/rvtrace/Makefile
index 988525a379cf..f320693a1fc5 100644
--- a/drivers/hwtracing/rvtrace/Makefile
+++ b/drivers/hwtracing/rvtrace/Makefile
@@ -2,3 +2,4 @@
 
 obj-$(CONFIG_RVTRACE) += rvtrace.o
 rvtrace-y := rvtrace-core.o rvtrace-platform.o
+obj-$(CONFIG_RVTRACE_ENCODER) += rvtrace-encoder.o
diff --git a/drivers/hwtracing/rvtrace/rvtrace-encoder.c b/drivers/hwtracing/rvtrace/rvtrace-encoder.c
new file mode 100644
index 000000000000..45d1c5b12c51
--- /dev/null
+++ b/drivers/hwtracing/rvtrace/rvtrace-encoder.c
@@ -0,0 +1,107 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2025 Ventana Micro Systems Inc.
+ */
+
+#include <linux/device.h>
+#include <linux/io.h>
+#include <linux/of.h>
+#include <linux/of_graph.h>
+#include <linux/platform_device.h>
+#include <linux/property.h>
+#include <linux/rvtrace.h>
+#include <linux/types.h>
+
+#define RVTRACE_COMPONENT_CTRL_ITRACE_MASK	0x1
+#define RVTRACE_COMPONENT_CTRL_ITRACE_SHIFT	2
+#define RVTRACE_COMPONENT_CTRL_INSTMODE_MASK	0x7
+#define RVTRACE_COMPONENT_CTRL_INSTMODE_SHIFT	4
+
+static int rvtrace_encoder_start(struct rvtrace_component *comp)
+{
+	u32 val;
+
+	val = rvtrace_read32(comp->pdata, RVTRACE_COMPONENT_CTRL_OFFSET);
+	val |= BIT(RVTRACE_COMPONENT_CTRL_ITRACE_SHIFT);
+	rvtrace_write32(comp->pdata, val, RVTRACE_COMPONENT_CTRL_OFFSET);
+	return rvtrace_poll_bit(comp->pdata, RVTRACE_COMPONENT_CTRL_OFFSET,
+				RVTRACE_COMPONENT_CTRL_ITRACE_SHIFT, 1,
+				comp->pdata->control_poll_timeout_usecs);
+}
+
+static int rvtrace_encoder_stop(struct rvtrace_component *comp)
+{
+	u32 val;
+
+	val = rvtrace_read32(comp->pdata, RVTRACE_COMPONENT_CTRL_OFFSET);
+	val &= ~BIT(RVTRACE_COMPONENT_CTRL_ITRACE_SHIFT);
+	rvtrace_write32(comp->pdata, val, RVTRACE_COMPONENT_CTRL_OFFSET);
+	return rvtrace_poll_bit(comp->pdata, RVTRACE_COMPONENT_CTRL_OFFSET,
+				RVTRACE_COMPONENT_CTRL_ITRACE_SHIFT, 0,
+				comp->pdata->control_poll_timeout_usecs);
+}
+
+static void rvtrace_encoder_setmode(struct rvtrace_component *comp, u32 mode)
+{
+	u32 val;
+
+	val = rvtrace_read32(comp->pdata, RVTRACE_COMPONENT_CTRL_OFFSET);
+	val |= (mode << RVTRACE_COMPONENT_CTRL_INSTMODE_SHIFT);
+	rvtrace_write32(comp->pdata, val, RVTRACE_COMPONENT_CTRL_OFFSET);
+}
+
+static int rvtrace_encoder_probe(struct rvtrace_component *comp)
+{
+	int ret;
+
+	rvtrace_encoder_setmode(comp, 0x6);
+	ret = rvtrace_enable_component(comp);
+	if (ret)
+		return dev_err_probe(&comp->dev, ret, "failed to enable encoder.\n");
+
+	return 0;
+}
+
+static void rvtrace_encoder_remove(struct rvtrace_component *comp)
+{
+	int ret;
+
+	ret = rvtrace_disable_component(comp);
+	if (ret)
+		dev_err(&comp->dev, "failed to disable encoder.\n");
+}
+
+static struct rvtrace_component_id rvtrace_encoder_ids[] = {
+	{ .type = RVTRACE_COMPONENT_TYPE_ENCODER,
+	  .version = rvtrace_component_mkversion(1, 0), },
+	{},
+};
+
+static struct rvtrace_driver rvtrace_encoder_driver = {
+	.id_table = rvtrace_encoder_ids,
+	.start = rvtrace_encoder_start,
+	.stop = rvtrace_encoder_stop,
+	.probe = rvtrace_encoder_probe,
+	.remove = rvtrace_encoder_remove,
+	.driver = {
+		.name = "rvtrace-encoder",
+	},
+};
+
+static int __init rvtrace_encoder_init(void)
+{
+	return rvtrace_register_driver(&rvtrace_encoder_driver);
+}
+
+static void __exit rvtrace_encoder_exit(void)
+{
+	rvtrace_unregister_driver(&rvtrace_encoder_driver);
+}
+
+module_init(rvtrace_encoder_init);
+module_exit(rvtrace_encoder_exit);
+
+/* Module information */
+MODULE_AUTHOR("Mayuresh Chitale <mchitale@ventanamicro.com>");
+MODULE_DESCRIPTION("RISC-V Trace Encoder Driver");
+MODULE_LICENSE("GPL");
-- 
2.43.0