Re: [PATCH v7 07/10] Coresight: Add TPDA link driver

From: Jinlong Mao
Date: Tue May 24 2022 - 03:34:05 EST


Hi Suzuki,

On 5/23/2022 5:40 PM, Suzuki K Poulose wrote:
On 09/05/2022 14:39, Mao Jinlong wrote:
TPDA(Trace, Profiling and Diagnostics Aggregator) is
to provide packetization, funneling and timestamping of
TPDM data. Multiple monitors are connected to different
input ports of TPDA.This change is to add tpda
enable/disable/probe functions for coresight tpda driver.

  - - - -         - - - -        - - - -
| TPDM 0|      | TPDM 1 |     | TPDM 2|
  - - - -         - - - -        - - - -
     |               |             |
     |_ _ _ _ _ _    |     _ _ _ _ |
                 |   |    |
                 |   |    |
            ------------------
           |        TPDA      |
            ------------------

Signed-off-by: Tao Zhang <quic_taozha@xxxxxxxxxxx>
Signed-off-by: Mao Jinlong <quic_jinlmao@xxxxxxxxxxx>
---
  drivers/hwtracing/coresight/Kconfig          |  11 +
  drivers/hwtracing/coresight/Makefile         |   1 +
  drivers/hwtracing/coresight/coresight-tpda.c | 201 +++++++++++++++++++
  drivers/hwtracing/coresight/coresight-tpda.h |  33 +++
  4 files changed, 246 insertions(+)
  create mode 100644 drivers/hwtracing/coresight/coresight-tpda.c
  create mode 100644 drivers/hwtracing/coresight/coresight-tpda.h

diff --git a/drivers/hwtracing/coresight/Kconfig b/drivers/hwtracing/coresight/Kconfig
index 5c506a1cd08f..447919565326 100644
--- a/drivers/hwtracing/coresight/Kconfig
+++ b/drivers/hwtracing/coresight/Kconfig
@@ -205,6 +205,7 @@ config CORESIGHT_TRBE
  config CORESIGHT_TPDM
      tristate "CoreSight Trace, Profiling & Diagnostics Monitor driver"
      select CORESIGHT_LINKS_AND_SINKS
+    select CORESIGHT_TPDA
      help
        This driver provides support for configuring monitor. Monitors are
        primarily responsible for data set collection and support the
@@ -214,4 +215,14 @@ config CORESIGHT_TPDM
        To compile this driver as a module, choose M here: the module will be
        called coresight-tpdm.
  +config CORESIGHT_TPDA
+    tristate "CoreSight Trace, Profiling & Diagnostics Aggregator driver"
+    help
+      This driver provides support for configuring aggregator. This is
+      primarily useful for pulling the data sets from one or more
+      attached monitors and pushing the resultant data out. Multiple
+      monitors are connected on different input ports of TPDA.
+
+      To compile this driver as a module, choose M here: the module will be
+      called coresight-tpda.
  endif
diff --git a/drivers/hwtracing/coresight/Makefile b/drivers/hwtracing/coresight/Makefile
index 6bb9b1746bc7..1712d82e7260 100644
--- a/drivers/hwtracing/coresight/Makefile
+++ b/drivers/hwtracing/coresight/Makefile
@@ -26,5 +26,6 @@ obj-$(CONFIG_CORESIGHT_CATU) += coresight-catu.o
  obj-$(CONFIG_CORESIGHT_CTI) += coresight-cti.o
  obj-$(CONFIG_CORESIGHT_TRBE) += coresight-trbe.o
  obj-$(CONFIG_CORESIGHT_TPDM) += coresight-tpdm.o
+obj-$(CONFIG_CORESIGHT_TPDA) += coresight-tpda.o
  coresight-cti-y := coresight-cti-core.o coresight-cti-platform.o \
             coresight-cti-sysfs.o
diff --git a/drivers/hwtracing/coresight/coresight-tpda.c b/drivers/hwtracing/coresight/coresight-tpda.c
new file mode 100644
index 000000000000..126286e89679
--- /dev/null
+++ b/drivers/hwtracing/coresight/coresight-tpda.c
@@ -0,0 +1,201 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2022 Qualcomm Innovation Center, Inc. All rights reserved.
+ */
+
+#include <linux/amba/bus.h>
+#include <linux/bitmap.h>
+#include <linux/coresight.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/fs.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+
+#include "coresight-priv.h"
+#include "coresight-tpda.h"
+#include "coresight-trace-id.h"
+
+DEFINE_CORESIGHT_DEVLIST(tpda_devs, "tpda");
+
+/* Settings pre enabling port control register */
+static void tpda_enable_pre_port(struct tpda_drvdata *drvdata)
+{
+    u32 val;
+
+    val = readl_relaxed(drvdata->base + TPDA_CR);
+    /* Bits 6 ~ 12 is for atid value */

minor nit, please could we use FIELD_PREP() and define the
ATID field in the TPDA_CR accordingly ?
I will check and update.

+    val |= (drvdata->atid << 6)

then we could have :

    val |= FIELD_PREP(TPDA_CR_ATID, drvdata->atid);

+    writel_relaxed(val, drvdata->base + TPDA_CR);
+}
+
+static void tpda_enable_port(struct tpda_drvdata *drvdata, int port)
+{
+    u32 val;
+
+    val = readl_relaxed(drvdata->base + TPDA_Pn_CR(port));
+    /* Enable the port */
+    val |= TPDA_Pn_CR_ENA;
+    writel_relaxed(val, drvdata->base + TPDA_Pn_CR(port));
+}
+
+static void _tpda_enable(struct tpda_drvdata *drvdata, int port)

minor nit: Similar to the tpdm, comment please use __tpda_{enable,disable}()
I will address this.

+{
+    CS_UNLOCK(drvdata->base);
+
+    if (!drvdata->enable)
+        tpda_enable_pre_port(drvdata);
+
+    tpda_enable_port(drvdata, port);
+
+    CS_LOCK(drvdata->base);
+}
+
+static int tpda_enable(struct coresight_device *csdev, int inport, int outport)
+{
+    struct tpda_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
+
+    mutex_lock(&drvdata->lock);
+    _tpda_enable(drvdata, inport);
+    drvdata->enable = true;

I am wondering if this is good enough ? Do we need a refcount ?
e.g, multiple TPDMs could be enabled independently and disabled
indpendently. And the tpda must stay alive until the last "source"
is gone away ?
it makes sense.

+    mutex_unlock(&drvdata->lock);
+
+    dev_info(drvdata->dev, "TPDA inport %d enabled\n", inport);
+    return 0;
+}
+
+static void _tpda_disable(struct tpda_drvdata *drvdata, int port)
+{
+    u32 val;
+
+    CS_UNLOCK(drvdata->base);
+
+    val = readl_relaxed(drvdata->base + TPDA_Pn_CR(port));
+    val &= ~TPDA_Pn_CR_ENA;
+    writel_relaxed(val, drvdata->base + TPDA_Pn_CR(port));
+
+    CS_LOCK(drvdata->base);
+}
+
+static void tpda_disable(struct coresight_device *csdev, int inport,
+               int outport)
+{
+    struct tpda_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
+
+    mutex_lock(&drvdata->lock);
+    _tpda_disable(drvdata, inport);
+    drvdata->enable = false;

This is not sufficient. We need to make sure the TPDA has a refcount of
the enabled ports.
I will update.

+    mutex_unlock(&drvdata->lock);
+
+    dev_info(drvdata->dev, "TPDA inport %d disabled\n", inport);
+}
+
+static const struct coresight_ops_link tpda_link_ops = {
+    .enable        = tpda_enable,
+    .disable    = tpda_disable,
+};
+
+static const struct coresight_ops tpda_cs_ops = {
+    .link_ops    = &tpda_link_ops,
+};
+
+static int tpda_init_default_data(struct tpda_drvdata *drvdata)
+{
+    int atid;
+    /*
+     * TPDA must has a unique atid. This atid can uniquely
+     * identify the TPDM trace source connect to the TPDA.

nit: s/connect/connected/

Also how do we identify the different TPDM sources
connected using a single atid ? Looking at the patch description
it is possible to have multiple TPDMs connected to a single TPDA.

+     */
+    atid = coresight_trace_id_get_system_id(coresight_get_trace_id_map());
+    if (atid < 0)
+        return atid;
+
+    drvdata->atid = atid;
+    return 0;
+}
+
+static int tpda_probe(struct amba_device *adev, const struct amba_id *id)
+{
+    int ret;
+    struct device *dev = &adev->dev;
+    struct coresight_platform_data *pdata;
+    struct tpda_drvdata *drvdata;
+    struct coresight_desc desc = { 0 };
+
+    pdata = coresight_get_platform_data(dev);
+    if (IS_ERR(pdata))
+        return PTR_ERR(pdata);
+    adev->dev.platform_data = pdata;
+
+    drvdata = devm_kzalloc(dev, sizeof(*drvdata), GFP_KERNEL);
+    if (!drvdata)
+        return -ENOMEM;
+
+    drvdata->dev = &adev->dev;
+    dev_set_drvdata(dev, drvdata);
+
+    drvdata->base = devm_ioremap_resource(dev, &adev->res);
+    if (!drvdata->base)
+        return -ENOMEM;
+
+    mutex_init(&drvdata->lock);
+
+    ret = tpda_init_default_data(drvdata);
+    if (ret)
+        return ret;
+
+    desc.name = coresight_alloc_device_name(&tpda_devs, dev);
+    if (!desc.name)
+        return -ENOMEM;
+    desc.type = CORESIGHT_DEV_TYPE_LINK;
+    desc.subtype.link_subtype = CORESIGHT_DEV_SUBTYPE_LINK_MERG;
+    desc.ops = &tpda_cs_ops;
+    desc.pdata = adev->dev.platform_data;
+    desc.dev = &adev->dev;

desc.access must be initialised.
I will address it.

+    drvdata->csdev = coresight_register(&desc);
+    if (IS_ERR(drvdata->csdev))
+        return PTR_ERR(drvdata->csdev);
+
+    pm_runtime_put(&adev->dev);
+
+    dev_dbg(drvdata->dev, "TPDA initialized\n");
+    return 0;
+}
+
+static void __exit tpda_remove(struct amba_device *adev)
+{
+    struct tpda_drvdata *drvdata = dev_get_drvdata(&adev->dev);
+
+    coresight_unregister(drvdata->csdev);
+}
+
+/*
+ * Different TPDA has different periph id.
+ * The difference is 0-7 bits' value. So ignore 0-7 bits.
+ */
+static struct amba_id tpda_ids[] = {
+    {
+        .id     = 0x000f0f00,
+        .mask   = 0x000fff00,
+    },
+    { 0, 0},
+};
+
+static struct amba_driver tpda_driver = {
+    .drv = {
+        .name   = "coresight-tpda",
+        .owner    = THIS_MODULE,
+        .suppress_bind_attrs = true,
+    },
+    .probe          = tpda_probe,
+    .remove        = tpda_remove,
+    .id_table    = tpda_ids,
+};
+
+module_amba_driver(tpda_driver);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("Trace, Profiling & Diagnostic Aggregator driver");
diff --git a/drivers/hwtracing/coresight/coresight-tpda.h b/drivers/hwtracing/coresight/coresight-tpda.h
new file mode 100644
index 000000000000..6df1b72b3b76
--- /dev/null
+++ b/drivers/hwtracing/coresight/coresight-tpda.h
@@ -0,0 +1,33 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2022 Qualcomm Innovation Center, Inc. All rights reserved.
+ */
+
+#ifndef _CORESIGHT_CORESIGHT_TPDA_H
+#define _CORESIGHT_CORESIGHT_TPDA_H
+
+#define TPDA_CR            (0x000)
+#define TPDA_Pn_CR(n)        (0x004 + (n * 4))
+/* Aggregator port enable bit */
+#define TPDA_Pn_CR_ENA        BIT(0)
+
+#define TPDA_MAX_INPORTS    32

Please add the bit fields for  TPDA_CR_ATID here and use
the FIELD_PREP()

#define TPDA_CR_ATID            GENMASK(12, 6)
I will check and update.

+
+/**
+ * struct tpda_drvdata - specifics associated to an TPDA component
+ * @base:       memory mapped base address for this component.
+ * @dev:        The device entity associated to this component.
+ * @csdev:      component vitals needed by the framework.
+ * @lock:       lock for the enable value.
+ * @enable:     enable status of the component.
+ */
+struct tpda_drvdata {
+    void __iomem        *base;
+    struct device        *dev;
+    struct coresight_device    *csdev;
+    struct mutex        lock;

Why mutex and not spinlock ?

Same as tpdm.

1. There is no irq for TPDA
2. There will be many registers to configure during enable/disable which may cause
some time.

+    bool            enable;
+    u32            atid;

    u8 atid ?
I will check.


Suzuki