linux-kernel - [PATCH v4 03/13] coresight: stm: Update STM driver to use Trace ID API

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Date:   Tue, 23 Aug 2022 10:09:59 +0100
From:   Mike Leach <mike.leach@...aro.org>
To:     coresight@...ts.linaro.org, linux-arm-kernel@...ts.infradead.org,
        linux-kernel@...r.kernel.org
Cc:     mathieu.poirier@...aro.org, suzuki.poulose@....com,
        peterz@...radead.org, mingo@...hat.com, acme@...nel.org,
        linux-perf-users@...r.kernel.org, leo.yan@...aro.org,
        quic_jinlmao@...cinc.com, Mike Leach <mike.leach@...aro.org>
Subject: [PATCH v4 03/13] coresight: stm: Update STM driver to use Trace ID API

Updates the STM driver to use the trace ID allocation API.
This uses the _system_id calls to allocate an ID on device poll,
and release on device remove.

The sysfs access to the STMTRACEIDR register has been changed from RW
to RO. Having this value as writable is not appropriate for the new
Trace ID scheme - and had potential to cause errors in the previous
scheme if values clashed with other sources.

Signed-off-by: Mike Leach <mike.leach@...aro.org>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@....com>
---
 drivers/hwtracing/coresight/coresight-stm.c | 41 +++++++--------------
 1 file changed, 14 insertions(+), 27 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-stm.c b/drivers/hwtracing/coresight/coresight-stm.c
index bb14a3a8a921..9ef3e923a930 100644
--- a/drivers/hwtracing/coresight/coresight-stm.c
+++ b/drivers/hwtracing/coresight/coresight-stm.c
@@ -31,6 +31,7 @@
 #include <linux/stm.h>
 
 #include "coresight-priv.h"
+#include "coresight-trace-id.h"
 
 #define STMDMASTARTR			0xc04
 #define STMDMASTOPR			0xc08
@@ -615,24 +616,7 @@ static ssize_t traceid_show(struct device *dev,
 	val = drvdata->traceid;
 	return sprintf(buf, "%#lx\n", val);
 }
-
-static ssize_t traceid_store(struct device *dev,
-			     struct device_attribute *attr,
-			     const char *buf, size_t size)
-{
-	int ret;
-	unsigned long val;
-	struct stm_drvdata *drvdata = dev_get_drvdata(dev->parent);
-
-	ret = kstrtoul(buf, 16, &val);
-	if (ret)
-		return ret;
-
-	/* traceid field is 7bit wide on STM32 */
-	drvdata->traceid = val & 0x7f;
-	return size;
-}
-static DEVICE_ATTR_RW(traceid);
+static DEVICE_ATTR_RO(traceid);
 
 #define coresight_stm_reg(name, offset)	\
 	coresight_simple_reg32(struct stm_drvdata, name, offset)
@@ -819,14 +803,6 @@ static void stm_init_default_data(struct stm_drvdata *drvdata)
 	 */
 	drvdata->stmsper = ~0x0;
 
-	/*
-	 * The trace ID value for *ETM* tracers start at CPU_ID * 2 + 0x10 and
-	 * anything equal to or higher than 0x70 is reserved.  Since 0x00 is
-	 * also reserved the STM trace ID needs to be higher than 0x00 and
-	 * lowner than 0x10.
-	 */
-	drvdata->traceid = 0x1;
-
 	/* Set invariant transaction timing on all channels */
 	bitmap_clear(drvdata->chs.guaranteed, 0, drvdata->numsp);
 }
@@ -854,7 +830,7 @@ static void stm_init_generic_data(struct stm_drvdata *drvdata,
 
 static int stm_probe(struct amba_device *adev, const struct amba_id *id)
 {
-	int ret;
+	int ret, trace_id;
 	void __iomem *base;
 	struct device *dev = &adev->dev;
 	struct coresight_platform_data *pdata = NULL;
@@ -938,12 +914,22 @@ static int stm_probe(struct amba_device *adev, const struct amba_id *id)
 		goto stm_unregister;
 	}
 
+	trace_id = coresight_trace_id_get_system_id();
+	if (trace_id < 0) {
+		ret = trace_id;
+		goto cs_unregister;
+	}
+	drvdata->traceid = (u8)trace_id;
+
 	pm_runtime_put(&adev->dev);
 
 	dev_info(&drvdata->csdev->dev, "%s initialized\n",
 		 (char *)coresight_get_uci_data(id));
 	return 0;
 
+cs_unregister:
+	coresight_unregister(drvdata->csdev);
+
 stm_unregister:
 	stm_unregister_device(&drvdata->stm);
 	return ret;
@@ -953,6 +939,7 @@ static void stm_remove(struct amba_device *adev)
 {
 	struct stm_drvdata *drvdata = dev_get_drvdata(&adev->dev);
 
+	coresight_trace_id_put_system_id(drvdata->traceid);
 	coresight_unregister(drvdata->csdev);
 
 	stm_unregister_device(&drvdata->stm);
-- 
2.17.1