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Message-ID: <20251002060732.100213-8-apatel@ventanamicro.com>
Date: Thu, 2 Oct 2025 11:37:28 +0530
From: Anup Patel <apatel@...tanamicro.com>
To: Rob Herring <robh@...nel.org>,
Krzysztof Kozlowski <krzk+dt@...nel.org>,
Conor Dooley <conor+dt@...nel.org>,
Paul Walmsley <paul.walmsley@...ive.com>,
Palmer Dabbelt <palmer@...belt.com>,
Greg KH <gregkh@...uxfoundation.org>,
Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
Ian Rogers <irogers@...gle.com>
Cc: Alexandre Ghiti <alex@...ti.fr>,
Peter Zijlstra <peterz@...radead.org>,
Ingo Molnar <mingo@...hat.com>,
Namhyung Kim <namhyung@...nel.org>,
Mark Rutland <mark.rutland@....com>,
Jiri Olsa <jolsa@...nel.org>,
Adrian Hunter <adrian.hunter@...el.com>,
Liang Kan <kan.liang@...ux.intel.com>,
Mayuresh Chitale <mchitale@...il.com>,
Anup Patel <anup@...infault.org>,
Atish Patra <atish.patra@...ux.dev>,
Andrew Jones <ajones@...tanamicro.com>,
Sunil V L <sunilvl@...tanamicro.com>,
linux-riscv@...ts.infradead.org,
devicetree@...r.kernel.org,
linux-kernel@...r.kernel.org,
Mayuresh Chitale <mchitale@...tanamicro.com>,
Anup Patel <apatel@...tanamicro.com>
Subject: [PATCH 07/11] rvtrace: Add trace ramsink driver
From: Mayuresh Chitale <mchitale@...tanamicro.com>
Add initial implementation of RISC-V trace ramsink driver. The ramsink
is defined in the RISC-V Trace Control Interface specification.
Co-developed-by: Anup Patel <apatel@...tanamicro.com>
Signed-off-by: Anup Patel <apatel@...tanamicro.com>
Signed-off-by: Mayuresh Chitale <mchitale@...tanamicro.com>
---
drivers/hwtracing/rvtrace/Kconfig | 8 +
drivers/hwtracing/rvtrace/Makefile | 1 +
drivers/hwtracing/rvtrace/rvtrace-ramsink.c | 198 ++++++++++++++++++++
3 files changed, 207 insertions(+)
create mode 100644 drivers/hwtracing/rvtrace/rvtrace-ramsink.c
diff --git a/drivers/hwtracing/rvtrace/Kconfig b/drivers/hwtracing/rvtrace/Kconfig
index ba35c05f3f54..aef7e9989165 100644
--- a/drivers/hwtracing/rvtrace/Kconfig
+++ b/drivers/hwtracing/rvtrace/Kconfig
@@ -21,3 +21,11 @@ config RVTRACE_ENCODER
default y
help
This driver provides support for RISC-V Trace Encoder component.
+
+config RVTRACE_RAMSINK
+ tristate "RISC-V Trace Ramsink driver"
+ depends on RVTRACE
+ default y
+ help
+ This driver provides support for Risc-V E-Trace Ramsink
+ component.
diff --git a/drivers/hwtracing/rvtrace/Makefile b/drivers/hwtracing/rvtrace/Makefile
index f320693a1fc5..122e575da9fb 100644
--- a/drivers/hwtracing/rvtrace/Makefile
+++ b/drivers/hwtracing/rvtrace/Makefile
@@ -3,3 +3,4 @@
obj-$(CONFIG_RVTRACE) += rvtrace.o
rvtrace-y := rvtrace-core.o rvtrace-platform.o
obj-$(CONFIG_RVTRACE_ENCODER) += rvtrace-encoder.o
+obj-$(CONFIG_RVTRACE_RAMSINK) += rvtrace-ramsink.o
diff --git a/drivers/hwtracing/rvtrace/rvtrace-ramsink.c b/drivers/hwtracing/rvtrace/rvtrace-ramsink.c
new file mode 100644
index 000000000000..7bd0cf1e4dfd
--- /dev/null
+++ b/drivers/hwtracing/rvtrace/rvtrace-ramsink.c
@@ -0,0 +1,198 @@
+// 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/dma-mapping.h>
+#include <linux/rvtrace.h>
+#include <linux/types.h>
+#include <linux/sizes.h>
+
+#define RVTRACE_RAMSINK_STARTLOW_OFF 0x010
+#define RVTRACE_RAMSINK_STARTHIGH_OFF 0x014
+#define RVTRACE_RAMSINK_LIMITLOW_OFF 0x018
+#define RVTRACE_RAMSINK_LIMITHIGH_OFF 0x01c
+#define RVTRACE_RAMSINK_WPLOW_OFF 0x020
+#define RVTRACE_RAMSINK_WPHIGH_OFF 0x024
+#define RVTRACE_RAMSINK_RPLOW_OFF 0x028
+#define RVTRACE_RAMSINK_RPHIGH_OFF 0x02c
+
+struct rvtrace_ramsink_priv {
+ size_t size;
+ void *va;
+ dma_addr_t start;
+ dma_addr_t end;
+ /* WP from prev iteration */
+ dma_addr_t prev_head;
+};
+
+struct trace_buf {
+ void *base;
+ size_t size;
+ int cur, len;
+};
+
+static void tbuf_to_pbuf_copy(struct trace_buf *src, struct trace_buf *dst)
+{
+ int bytes_dst, bytes_src, bytes;
+ void *dst_addr, *src_addr;
+
+ while (src->size) {
+ src_addr = src->base + src->cur;
+ dst_addr = dst->base + dst->cur;
+
+ if (dst->len - dst->cur < src->size)
+ bytes_dst = dst->len - dst->cur;
+ else
+ bytes_dst = src->size;
+ if (src->len - src->cur < src->size)
+ bytes_src = src->len - src->cur;
+ else
+ bytes_src = src->size;
+ bytes = bytes_dst < bytes_src ? bytes_dst : bytes_src;
+ memcpy(dst_addr, src_addr, bytes);
+ dst->cur = (dst->cur + bytes) % dst->len;
+ src->cur = (src->cur + bytes) % src->len;
+ src->size -= bytes;
+ }
+}
+
+static size_t rvtrace_ramsink_copyto_auxbuf(struct rvtrace_component *comp,
+ struct rvtrace_perf_auxbuf *buf)
+{
+ struct rvtrace_ramsink_priv *priv = dev_get_drvdata(&comp->dev);
+ struct trace_buf src, dst;
+ u32 wp_low, wp_high;
+ u64 buf_cur_head;
+ size_t size;
+
+ wp_low = rvtrace_read32(comp->pdata, RVTRACE_RAMSINK_WPLOW_OFF);
+ wp_high = rvtrace_read32(comp->pdata, RVTRACE_RAMSINK_WPHIGH_OFF);
+ buf_cur_head = (u64)(wp_high) << 32 | wp_low;
+
+ if (buf_cur_head == priv->prev_head)
+ return 0;
+
+ dst.base = buf->base;
+ dst.len = buf->length;
+ dst.cur = buf->pos;
+ dst.size = 0;
+
+ src.base = priv->va;
+ src.len = priv->end - priv->start;
+ if (buf_cur_head > priv->prev_head) {
+ src.size = buf_cur_head - priv->prev_head;
+ } else {
+ src.size = priv->end - priv->prev_head;
+ src.size += buf_cur_head - priv->start;
+ }
+
+ src.cur = buf_cur_head - priv->start;
+ size = src.size;
+ tbuf_to_pbuf_copy(&src, &dst);
+ buf->pos = dst.cur;
+ priv->prev_head = buf_cur_head;
+
+ return size;
+}
+
+static int rvtrace_ramsink_setup(struct rvtrace_component *comp)
+{
+ struct rvtrace_ramsink_priv *priv;
+
+ priv = devm_kzalloc(&comp->dev, sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+ dev_set_drvdata(&comp->dev, priv);
+
+ priv->size = SZ_4M;
+ priv->va = dma_alloc_coherent(&comp->dev, priv->size, &priv->start, GFP_KERNEL);
+ if (!priv->va)
+ return -ENOMEM;
+ priv->end = priv->start + priv->size;
+ priv->prev_head = priv->start;
+
+ /* Setup ram sink addresses */
+ rvtrace_write32(comp->pdata, lower_32_bits(priv->start), RVTRACE_RAMSINK_STARTLOW_OFF);
+ rvtrace_write32(comp->pdata, upper_32_bits(priv->start), RVTRACE_RAMSINK_STARTHIGH_OFF);
+ rvtrace_write32(comp->pdata, lower_32_bits(priv->start), RVTRACE_RAMSINK_WPLOW_OFF);
+ rvtrace_write32(comp->pdata, upper_32_bits(priv->start), RVTRACE_RAMSINK_WPHIGH_OFF);
+ /* Limit address needs to be set to end - 4 so that HW doesn't cause an overflow. */
+ rvtrace_write32(comp->pdata, lower_32_bits(priv->end - 0x4), RVTRACE_RAMSINK_LIMITLOW_OFF);
+ rvtrace_write32(comp->pdata, upper_32_bits(priv->end), RVTRACE_RAMSINK_LIMITHIGH_OFF);
+
+ return 0;
+}
+
+static void rvtrace_ramsink_cleanup(struct rvtrace_component *comp)
+{
+ struct rvtrace_ramsink_priv *priv = dev_get_drvdata(&comp->dev);
+
+ dma_free_coherent(&comp->dev, priv->size, priv->va, priv->start);
+}
+
+static int rvtrace_ramsink_probe(struct rvtrace_component *comp)
+{
+ int ret;
+
+ ret = rvtrace_ramsink_setup(comp);
+ if (ret)
+ return dev_err_probe(&comp->dev, ret, "failed to setup ramsink.\n");
+
+ ret = rvtrace_enable_component(comp);
+ if (ret)
+ return dev_err_probe(&comp->dev, ret, "failed to enable ramsink.\n");
+
+ return ret;
+}
+
+static void rvtrace_ramsink_remove(struct rvtrace_component *comp)
+{
+ int ret;
+
+ ret = rvtrace_disable_component(comp);
+ if (ret)
+ dev_err(&comp->dev, "failed to disable ramsink.\n");
+
+ rvtrace_ramsink_cleanup(comp);
+}
+
+static struct rvtrace_component_id rvtrace_ramsink_ids[] = {
+ { .type = RVTRACE_COMPONENT_TYPE_RAMSINK,
+ .version = rvtrace_component_mkversion(1, 0), },
+ {},
+};
+
+static struct rvtrace_driver rvtrace_ramsink_driver = {
+ .id_table = rvtrace_ramsink_ids,
+ .copyto_auxbuf = rvtrace_ramsink_copyto_auxbuf,
+ .probe = rvtrace_ramsink_probe,
+ .remove = rvtrace_ramsink_remove,
+ .driver = {
+ .name = "rvtrace-ramsink",
+ },
+};
+
+static int __init rvtrace_ramsink_init(void)
+{
+ return rvtrace_register_driver(&rvtrace_ramsink_driver);
+}
+
+static void __exit rvtrace_ramsink_exit(void)
+{
+ rvtrace_unregister_driver(&rvtrace_ramsink_driver);
+}
+
+module_init(rvtrace_ramsink_init);
+module_exit(rvtrace_ramsink_exit);
+
+/* Module information */
+MODULE_AUTHOR("Mayuresh Chitale <mchitale@...tanamicro.com>");
+MODULE_DESCRIPTION("RISC-V Trace Ramsink Driver");
+MODULE_LICENSE("GPL");
--
2.43.0
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