Re: [PATCH v11 6/9] Coresight: Add TPDA link driver

From: Jinlong Mao
Date: Fri Jul 01 2022 - 11:10:38 EST


Hi Suzuki,

Thanks for the review.

On 7/1/2022 6:24 PM, Suzuki K Poulose wrote:
On 20/06/2022 13:00, 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 | 206 +++++++++++++++++++
  drivers/hwtracing/coresight/coresight-tpda.h |  35 ++++
  4 files changed, 253 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 b2b72a35e416..0cbebfd0d23e 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
@@ -213,4 +214,14 @@ 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..7a0478a8b63e
--- /dev/null
+++ b/drivers/hwtracing/coresight/coresight-tpda.c
@@ -0,0 +1,206 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2022 Qualcomm Innovation Center, Inc. All rights reserved.
+ */
+
+#include <linux/amba/bus.h>
+#include <linux/bitfield.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);


Even though the drvdata->atid is constant during the life time
of the driver, I would recommend clearing the field and then
setting it. e.g, if you get a different ATID on unload-load
sequence of the driver, the field will corrupted.
I will release the id in module exist function.

    val &= ~TPDA_CR_ATID;

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


+    writel_relaxed(val, drvdata->base + TPDA_CR);
+}
+

Is there no global turn-ON for the TPDA ? Or is it per-port
enable only via TPDA_Pn_CR ?


No global turn-on for the TPDA.  It is per-port enable via TPDA_Pn_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)
+{
+    CS_UNLOCK(drvdata->base);
+
+    if (!drvdata->csdev->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);
+
+    spin_lock(&drvdata->spinlock);
+    if (atomic_read(&csdev->refcnt[inport]) == 0)
+        __tpda_enable(drvdata, inport);
+
+    atomic_inc(&csdev->refcnt[inport]);
+    spin_unlock(&drvdata->spinlock);
+
+    dev_dbg(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);
+
+    spin_lock(&drvdata->spinlock);
+    if (atomic_dec_return(&csdev->refcnt[inport]) == 0)
+        __tpda_disable(drvdata, inport);
+
+    spin_unlock(&drvdata->spinlock);
+
+    dev_dbg(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)
+{

Is there a register that indicates the number of ports on the device ?
We don't seem to be using that information.
No such register.

+    int atid;
+    /*
+     * TPDA must has a unique atid. This atid can uniquely
+     * identify the TPDM trace source connected to the TPDA.
+     */
+    atid = coresight_trace_id_get_system_id(coresight_get_trace_id_map());
+    if (atid < 0)
+        return atid;
+

You need to release this id at module exit. Otherwise, we are leaking
the id.

I will address the comments.

Suzuki