perf/imx_ddr: Add support for AXI ID filtering

AXI filtering is used by events 0x41 and 0x42 to count reads or writes
with an ARID or AWID matching a specified filter. The filter is exposed
to userspace as an (ID, MASK) pair, where each set bit in the mask
causes the corresponding bit in the ID to be ignored when matching
against the ID of memory transactions for the purposes of incrementing
the counter.

For example:

  # perf stat -a -e imx8_ddr0/axid-read,axi_mask=0xff,axi_id=0x800/ cmd

will count all read transactions from AXI IDs 0x800 - 0x8ff. If the
'axi_mask' is omitted, then it is treated as 0x0 which means that the
'axi_id' will be matched exactly.

Signed-off-by: Joakim Zhang <qiangqing.zhang@nxp.com>
Signed-off-by: Will Deacon <will@kernel.org>

drivers/perf/fsl_imx8_ddr_perf.c

@@ -35,6 +35,8 @@
 #define EVENT_CYCLES_COUNTER	0
 #define NUM_COUNTERS		4
 
+#define AXI_MASKING_REVERT	0xffff0000	/* AXI_MASKING(MSB 16bits) + AXI_ID(LSB 16bits) */
+
 #define to_ddr_pmu(p)		container_of(p, struct ddr_pmu, pmu)
 
 #define DDR_PERF_DEV_NAME	"imx8_ddr"
@@ -42,9 +44,22 @@
 
 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 */ }
 };
 MODULE_DEVICE_TABLE(of, imx_ddr_pmu_dt_ids);
@@ -58,6 +73,7 @@ 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;
 };
@@ -129,6 +145,8 @@ 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(axid-read, 0x41),
+	IMX8_DDR_PMU_EVENT_ATTR(axid-write, 0x42),
 	NULL,
 };
 
@@ -138,9 +156,13 @@ static struct attribute_group ddr_perf_events_attr_group = {
 };
 
 PMU_FORMAT_ATTR(event, "config:0-7");
+PMU_FORMAT_ATTR(axi_id, "config1:0-15");
+PMU_FORMAT_ATTR(axi_mask, "config1:16-31");
 
 static struct attribute *ddr_perf_format_attrs[] = {
 	&format_attr_event.attr,
+	&format_attr_axi_id.attr,
+	&format_attr_axi_mask.attr,
 	NULL,
 };
 
@@ -190,6 +212,26 @@ static u32 ddr_perf_read_counter(struct ddr_pmu *pmu, int counter)
 	return readl_relaxed(pmu->base + COUNTER_READ + counter * 4);
 }
 
+static bool ddr_perf_is_filtered(struct perf_event *event)
+{
+	return event->attr.config == 0x41 || event->attr.config == 0x42;
+}
+
+static u32 ddr_perf_filter_val(struct perf_event *event)
+{
+	return event->attr.config1;
+}
+
+static bool ddr_perf_filters_compatible(struct perf_event *a,
+					struct perf_event *b)
+{
+	if (!ddr_perf_is_filtered(a))
+		return true;
+	if (!ddr_perf_is_filtered(b))
+		return true;
+	return ddr_perf_filter_val(a) == ddr_perf_filter_val(b);
+}
+
 static int ddr_perf_event_init(struct perf_event *event)
 {
 	struct ddr_pmu *pmu = to_ddr_pmu(event->pmu);
@@ -216,6 +258,15 @@ static int ddr_perf_event_init(struct perf_event *event)
 			!is_software_event(event->group_leader))
 		return -EINVAL;
 
+	if (pmu->devtype_data->quirks & DDR_CAP_AXI_ID_FILTER) {
+		if (!ddr_perf_filters_compatible(event, event->group_leader))
+			return -EINVAL;
+		for_each_sibling_event(sibling, event->group_leader) {
+			if (!ddr_perf_filters_compatible(event, sibling))
+				return -EINVAL;
+		}
+	}
+
 	for_each_sibling_event(sibling, event->group_leader) {
 		if (sibling->pmu != event->pmu &&
 				!is_software_event(sibling))
@@ -288,6 +339,23 @@ static int ddr_perf_event_add(struct perf_event *event, int flags)
 	struct hw_perf_event *hwc = &event->hw;
 	int counter;
 	int cfg = event->attr.config;
+	int cfg1 = event->attr.config1;
+
+	if (pmu->devtype_data->quirks & DDR_CAP_AXI_ID_FILTER) {
+		int i;
+
+		for (i = 1; i < NUM_COUNTERS; i++) {
+			if (pmu->events[i] &&
+			    !ddr_perf_filters_compatible(event, pmu->events[i]))
+				return -EINVAL;
+		}
+
+		if (ddr_perf_is_filtered(event)) {
+			/* revert axi id masking(axi_mask) value */
+			cfg1 ^= AXI_MASKING_REVERT;
+			writel(cfg1, pmu->base + COUNTER_DPCR1);
+		}
+	}
 
 	counter = ddr_perf_alloc_counter(pmu, cfg);
 	if (counter < 0) {
@@ -473,6 +541,8 @@ static int ddr_perf_probe(struct platform_device *pdev)
 	if (!name)
 		return -ENOMEM;
 
+	pmu->devtype_data = of_device_get_match_data(&pdev->dev);
+
 	pmu->cpu = raw_smp_processor_id();
 	ret = cpuhp_setup_state_multi(CPUHP_AP_ONLINE_DYN,
 				      DDR_CPUHP_CB_NAME,