[PATCH] perf: imx8_ddr_perf: add AXI ID filter support

[Joakim Zhang <qiangqing.zhang@nxp.com>]

AXI filtering is used by CSV modes 0x41 and 0x42 to count reads or
writes with an ARID or AXID matching filter setting. Granularity is at
subsystem level. Implementation does not allow filtring between masters
within a subsystem. Filter is defined with 2 configuration registers.

--AXI_ID defines AxID matching value
--AXI_MASKING defines which bits of AxID are meaningful for the matching

When non-masked bits are matching corresponding AXI_ID bits then counter
is incremented. This filter allows counting read or write access from a
subsystem or multiple subsystems.

Perf counter is incremented if AxID && AXI_MASKING == AXI_ID && AXI_MASKING

AXI_ID and AXI_MASKING are mapped on DPCR1 register in performance counter.

e.g.
perf stat -a -e imx8_ddr0/axi-id-read,axi_id=0xMMMMDDDD/ cmd
MMMM: AXI_MASKING
DDDD: AXI_ID

Signed-off-by: Joakim Zhang <qiangqing.zhang@nxp.com>
---
 drivers/perf/fsl_imx8_ddr_perf.c | 38 ++++++++++++++++++++++++++++++--
 1 file changed, 36 insertions(+), 2 deletions(-)

diff --git a/drivers/perf/fsl_imx8_ddr_perf.c b/drivers/perf/fsl_imx8_ddr_perf.c
index 63fe21600072..cd05f12ed5c4 100644
--- a/drivers/perf/fsl_imx8_ddr_perf.c
+++ b/drivers/perf/fsl_imx8_ddr_perf.c
@@ -42,9 +42,22 @@
 
 static DEFINE_IDA(ddr_ida);
 
+/* DDR Perf hardware feature */
+#define DDR_CAP_AXI_ID_FILTER		0x1	/* support AXI ID filter */
+
+struct fsl_ddr_devtype_data {
+	unsigned int quirks;	/* quirks needed for different DDR Perf core */
+};
+
+static const struct fsl_ddr_devtype_data imx8_devtype_data;
+
+static const struct fsl_ddr_devtype_data imx8m_devtype_data = {
+	.quirks = DDR_CAP_AXI_ID_FILTER,
+};
+
 static const struct of_device_id imx_ddr_pmu_dt_ids[] = {
-	{ .compatible = "fsl,imx8-ddr-pmu",},
-	{ .compatible = "fsl,imx8m-ddr-pmu",},
+	{ .compatible = "fsl,imx8-ddr-pmu", .data = &imx8_devtype_data},
+	{ .compatible = "fsl,imx8m-ddr-pmu", .data = &imx8m_devtype_data},
 	{ /* sentinel */ }
 };
 
@@ -57,6 +70,7 @@ struct ddr_pmu {
 	struct perf_event *events[NUM_COUNTERS];
 	int active_events;
 	enum cpuhp_state cpuhp_state;
+	const struct fsl_ddr_devtype_data *devtype_data;
 	int irq;
 	int id;
 };
@@ -128,6 +142,8 @@ static struct attribute *ddr_perf_events_attrs[] = {
 	IMX8_DDR_PMU_EVENT_ATTR(refresh, 0x37),
 	IMX8_DDR_PMU_EVENT_ATTR(write, 0x38),
 	IMX8_DDR_PMU_EVENT_ATTR(raw-hazard, 0x39),
+	IMX8_DDR_PMU_EVENT_ATTR(axi-id-read, 0x41),
+	IMX8_DDR_PMU_EVENT_ATTR(axi-id-write, 0x42),
 	NULL,
 };
 
@@ -137,9 +153,11 @@ static struct attribute_group ddr_perf_events_attr_group = {
 };
 
 PMU_FORMAT_ATTR(event, "config:0-7");
+PMU_FORMAT_ATTR(axi_id, "config1:0-31");
 
 static struct attribute *ddr_perf_format_attrs[] = {
 	&format_attr_event.attr,
+	&format_attr_axi_id.attr,
 	NULL,
 };
 
@@ -274,6 +292,15 @@ static void ddr_perf_event_start(struct perf_event *event, int flags)
 	struct hw_perf_event *hwc = &event->hw;
 	int counter = hwc->idx;
 
+	if (pmu->devtype_data->quirks & DDR_CAP_AXI_ID_FILTER) {
+		if (event->attr.config == 0x41 ||
+		    event->attr.config == 0x42) {
+			int val = event->attr.config1;
+
+			writel(val, pmu->base + COUNTER_DPCR1);
+		}
+	}
+
 	local64_set(&hwc->prev_count, 0);
 
 	ddr_perf_counter_enable(pmu, event->attr.config, counter, true);
@@ -445,6 +472,7 @@ static int ddr_perf_offline_cpu(unsigned int cpu, struct hlist_node *node)
 
 static int ddr_perf_probe(struct platform_device *pdev)
 {
+	const struct of_device_id *of_id;
 	struct ddr_pmu *pmu;
 	struct device_node *np;
 	void __iomem *base;
@@ -472,6 +500,12 @@ static int ddr_perf_probe(struct platform_device *pdev)
 	if (!name)
 		return -ENOMEM;
 
+	of_id = of_match_device(imx_ddr_pmu_dt_ids, &pdev->dev);
+	if (of_id)
+		pmu->devtype_data = of_id->data;
+	else
+		return -ENODEV;
+
 	pmu->cpu = raw_smp_processor_id();
 	ret = cpuhp_setup_state_multi(CPUHP_AP_ONLINE_DYN,
 				      DDR_CPUHP_CB_NAME,
-- 
2.17.1


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel