[RFC PATCH 04/12] coresight: Add RISC-V Trace Funnel driver
Zane Leung
liangzhen at linux.spacemit.com
Mon Apr 13 20:41:45 PDT 2026
From: liangzhen <zhen.liang at spacemit.com>
Add initial implementation of RISC-V trace funnel
driver. The funnel is defined in the RISC-V Trace
Control Interface specification.
Signed-off-by: liangzhen <zhen.liang at spacemit.com>
---
drivers/hwtracing/coresight/Kconfig | 12 +
drivers/hwtracing/coresight/Makefile | 1 +
drivers/hwtracing/coresight/rvtrace-funnel.c | 244 +++++++++++++++++++
drivers/hwtracing/coresight/rvtrace-funnel.h | 31 +++
4 files changed, 288 insertions(+)
create mode 100644 drivers/hwtracing/coresight/rvtrace-funnel.c
create mode 100644 drivers/hwtracing/coresight/rvtrace-funnel.h
diff --git a/drivers/hwtracing/coresight/Kconfig b/drivers/hwtracing/coresight/Kconfig
index 3e46728f2482..8381a84e2699 100644
--- a/drivers/hwtracing/coresight/Kconfig
+++ b/drivers/hwtracing/coresight/Kconfig
@@ -288,9 +288,21 @@ config RVTRACE
dynamically aggregated with CoreSight trace infrastructure
at run time to form a complete trace path.
+config RVTRACE_FUNNEL
+ tristate "RISCV Trace Funnel driver"
+ depends on RVTRACE
+ help
+ his driver provides support for the Trace Funnel driver. The Funnel
+ aggregates the trace from each of its inputs and sends the combined
+ trace stream to its designated Trace Sink or ATB Bridge.
+
+ To compile this driver as a module, choose M here: the module
+ will be called rvtrace-funnel.
+
config RVTRACE_ENCODER
tristate "RISCV Trace Encoder driver"
depends on RVTRACE
+ select RVTRACE_FUNNEL
help
This driver provides support for the Trace Encoder module, tracing
the instructions that a processor is executing. This is primarily
diff --git a/drivers/hwtracing/coresight/Makefile b/drivers/hwtracing/coresight/Makefile
index 9a526b1fb95a..409a0abf0642 100644
--- a/drivers/hwtracing/coresight/Makefile
+++ b/drivers/hwtracing/coresight/Makefile
@@ -59,5 +59,6 @@ coresight-ctcu-y := coresight-ctcu-core.o
obj-$(CONFIG_CORESIGHT_KUNIT_TESTS) += coresight-kunit-tests.o
obj-$(CONFIG_RVTRACE) += rvtrace.o
rvtrace-y := rvtrace-core.o
+obj-$(CONFIG_RVTRACE_FUNNEL) += rvtrace-funnel.o
obj-$(CONFIG_RVTRACE_ENCODER) += rvtrace-encoder.o
rvtrace-encoder-y := rvtrace-encoder-core.o rvtrace-encoder-sysfs.o
diff --git a/drivers/hwtracing/coresight/rvtrace-funnel.c b/drivers/hwtracing/coresight/rvtrace-funnel.c
new file mode 100644
index 000000000000..0dc7799a64ac
--- /dev/null
+++ b/drivers/hwtracing/coresight/rvtrace-funnel.c
@@ -0,0 +1,244 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright(C) 2026 Spacemit Limited. All rights reserved.
+ */
+
+#include <linux/kernel.h>
+#include <linux/coresight.h>
+#include <linux/platform_device.h>
+#include <linux/rvtrace.h>
+
+#include "coresight-priv.h"
+#include "rvtrace-funnel.h"
+
+DEFINE_CORESIGHT_DEVLIST(funnel_devs, "rvtrace_funnel");
+
+static int funnel_enable_hw(struct rvtrace_component *comp, int port)
+{
+ u32 disinput;
+ int ret = 0;
+ struct funnel_data *funnel_data = rvtrace_component_data(comp);
+
+ if (!comp->was_reset) {
+ ret = rvtrace_component_reset(comp);
+ if (ret)
+ goto done;
+ }
+
+ disinput = readl_relaxed(comp->base + RVTRACE_FUNNEL_DISINPUT_OFFSET);
+ disinput &= ~(1 << port);
+ writel_relaxed(disinput, comp->base + RVTRACE_FUNNEL_DISINPUT_OFFSET);
+ ret = rvtrace_poll_bit(comp, RVTRACE_FUNNEL_DISINPUT_OFFSET, port, 0);
+ if (ret)
+ goto done;
+
+ if (!funnel_data->was_enabled) {
+ ret = rvtrace_enable_component(comp);
+ if (ret)
+ goto done;
+ }
+
+done:
+ return ret;
+}
+
+static int funnel_enable(struct coresight_device *csdev,
+ struct coresight_connection *in,
+ struct coresight_connection *out)
+{
+ int ret = 0;
+ struct rvtrace_component *comp = dev_get_drvdata(csdev->dev.parent);
+ struct funnel_data *funnel_data = rvtrace_component_data(comp);
+ unsigned long flags;
+ bool first_enable = false;
+
+ spin_lock_irqsave(&funnel_data->spinlock, flags);
+ if (in->dest_refcnt == 0) {
+ ret = funnel_enable_hw(comp, in->dest_port);
+ if (!ret)
+ first_enable = true;
+ }
+ if (!ret) {
+ in->dest_refcnt++;
+ funnel_data->input_refcnt++;
+ }
+
+ if (first_enable)
+ dev_dbg(&csdev->dev, "Trace funnel inport %d enabled\n",
+ in->dest_port);
+
+ spin_unlock_irqrestore(&funnel_data->spinlock, flags);
+
+ return ret;
+}
+
+static void funnel_disable_hw(struct rvtrace_component *comp, int inport)
+{
+ struct funnel_data *funnel_data = rvtrace_component_data(comp);
+
+ if (--funnel_data->input_refcnt != 0)
+ return;
+
+ writel_relaxed(RVTRACE_FUNNEL_DISINPUT_MASK, comp->base + RVTRACE_FUNNEL_DISINPUT_OFFSET);
+
+ if (rvtrace_disable_component(comp))
+ dev_err(&funnel_data->csdev->dev,
+ "timeout while waiting for Trace Funnel to be disabled\n");
+
+ if (rvtrace_comp_is_empty(comp))
+ dev_err(&funnel_data->csdev->dev,
+ "timeout while waiting for Trace Funnel internal buffers become empty\n");
+}
+
+static void funnel_disable(struct coresight_device *csdev,
+ struct coresight_connection *in,
+ struct coresight_connection *out)
+{
+ struct rvtrace_component *comp = dev_get_drvdata(csdev->dev.parent);
+ struct funnel_data *funnel_data = rvtrace_component_data(comp);
+ unsigned long flags;
+ bool last_disable = false;
+
+ spin_lock_irqsave(&funnel_data->spinlock, flags);
+ if (--in->dest_refcnt == 0) {
+ funnel_disable_hw(comp, in->dest_port);
+ last_disable = true;
+ }
+ spin_unlock_irqrestore(&funnel_data->spinlock, flags);
+
+ if (last_disable)
+ dev_dbg(&csdev->dev, "Trace funnel inport %d disabled\n",
+ in->dest_port);
+
+ if (funnel_data->input_refcnt == 0)
+ dev_dbg(&csdev->dev, "Trace funnel disabled\n");
+}
+
+static const struct coresight_ops_link funnel_link_ops = {
+ .enable = funnel_enable,
+ .disable = funnel_disable,
+};
+
+static const struct coresight_ops funnel_cs_ops = {
+ .link_ops = &funnel_link_ops,
+};
+
+static ssize_t reset_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t size)
+{
+ unsigned long val;
+ struct rvtrace_component *comp = dev_get_drvdata(dev->parent);
+ struct funnel_data *funnel_data = rvtrace_component_data(comp);
+ unsigned long flags;
+
+ if (kstrtoul(buf, 16, &val))
+ return -EINVAL;
+
+ spin_lock_irqsave(&funnel_data->spinlock, flags);
+
+ if (val) {
+ if (rvtrace_component_reset(comp)) {
+ comp->was_reset = false;
+ spin_unlock_irqrestore(&funnel_data->spinlock, flags);
+ return -EINVAL;
+ }
+ }
+
+ spin_unlock_irqrestore(&funnel_data->spinlock, flags);
+
+ return size;
+}
+static DEVICE_ATTR_WO(reset);
+
+static ssize_t cpu_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ unsigned long val;
+ struct rvtrace_component *comp = dev_get_drvdata(dev->parent);
+
+ val = comp->cpu;
+ return scnprintf(buf, PAGE_SIZE, "%#lx\n", val);
+}
+static DEVICE_ATTR_RO(cpu);
+
+static struct attribute *trace_funnel_attrs[] = {
+ coresight_simple_reg32(control, RVTRACE_COMPONENT_CTRL_OFFSET),
+ coresight_simple_reg32(impl, RVTRACE_COMPONENT_IMPL_OFFSET),
+ coresight_simple_reg32(disinput, RVTRACE_FUNNEL_DISINPUT_OFFSET),
+ &dev_attr_reset.attr,
+ &dev_attr_cpu.attr,
+ NULL,
+};
+ATTRIBUTE_GROUPS(trace_funnel);
+
+static int funnel_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct coresight_platform_data *pdata;
+ struct funnel_data *funnel_data;
+ struct rvtrace_component *comp;
+ struct coresight_desc desc = { 0 };
+
+ comp = rvtrace_register_component(pdev);
+ if (IS_ERR(comp))
+ return PTR_ERR(comp);
+
+ funnel_data = devm_kzalloc(dev, sizeof(*funnel_data), GFP_KERNEL);
+ if (!funnel_data)
+ return -ENOMEM;
+
+ spin_lock_init(&funnel_data->spinlock);
+
+ pdata = coresight_get_platform_data(dev);
+ if (IS_ERR(pdata))
+ return PTR_ERR(pdata);
+ pdev->dev.platform_data = pdata;
+
+ platform_set_drvdata(pdev, comp);
+
+ desc.name = coresight_alloc_device_name(&funnel_devs, dev);
+ desc.access = CSDEV_ACCESS_IOMEM(comp->base);
+ desc.type = CORESIGHT_DEV_TYPE_LINK;
+ desc.subtype.link_subtype = CORESIGHT_DEV_SUBTYPE_LINK_MERG;
+ desc.ops = &funnel_cs_ops;
+ desc.pdata = pdata;
+ desc.dev = dev;
+ desc.groups = trace_funnel_groups;
+ funnel_data->csdev = coresight_register(&desc);
+ if (IS_ERR(funnel_data->csdev))
+ return PTR_ERR(funnel_data->csdev);
+
+ comp->id.data = funnel_data;
+
+ dev_dbg(dev, "Trace Funnel initialized\n");
+
+ return 0;
+}
+
+static void funnel_remove(struct platform_device *pdev)
+{
+ struct rvtrace_component *comp = platform_get_drvdata(pdev);
+ struct funnel_data *funnel_data = rvtrace_component_data(comp);
+
+ coresight_unregister(funnel_data->csdev);
+}
+
+static const struct of_device_id funnel_match[] = {
+ {.compatible = "riscv,trace-funnel"},
+ {},
+};
+
+static struct platform_driver funnel_driver = {
+ .probe = funnel_probe,
+ .remove = funnel_remove,
+ .driver = {
+ .name = "trace-funnel",
+ .of_match_table = funnel_match,
+ },
+};
+
+module_platform_driver(funnel_driver);
+
+MODULE_DESCRIPTION("RISC-V Trace funnel driver");
+MODULE_LICENSE("GPL");
diff --git a/drivers/hwtracing/coresight/rvtrace-funnel.h b/drivers/hwtracing/coresight/rvtrace-funnel.h
new file mode 100644
index 000000000000..e5247e6c1bf5
--- /dev/null
+++ b/drivers/hwtracing/coresight/rvtrace-funnel.h
@@ -0,0 +1,31 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright(C) 2026 Spacemit Limited. All rights reserved.
+ */
+
+#ifndef _RVTRACE_FUNNEL_H
+#define _RVTRACE_FUNNEL_H
+
+#include <linux/spinlock.h>
+#include <linux/coresight.h>
+
+/* Disable Individual Funnel Inputs */
+#define RVTRACE_FUNNEL_DISINPUT_OFFSET 0x008
+#define RVTRACE_FUNNEL_DISINPUT_MASK 0xffff
+
+/**
+ * struct funnel_data - specifics associated to a Trace Funnel component
+ * @csdev: Component vitals needed by the framework.
+ * @spinlock: Only one at a time pls.
+ * @was_enabled: Flag showing whether the Trace Funnel was enabled.
+ * @input_refcnt: Record the number of funnel inputs
+ */
+struct funnel_data {
+ struct coresight_device *csdev;
+ spinlock_t spinlock;
+ bool was_enabled;
+ u32 input_refcnt;
+ u32 disintput;
+};
+
+#endif
--
2.34.1
More information about the linux-riscv
mailing list