[PATCH v3 0/4] soc/arm64: qcom: Add initial version of bwmon

[PATCH v3 0/4] soc/arm64: qcom: Add initial version of bwmon

[Krzysztof Kozlowski]

Hi,

Changes since v2
================
1. Spent a lot of time on benchmarking and learning the BWMON behavior.
2. Drop PM/OPP patch - applied.
3. Patch #1: drop opp-avg-kBps.
4. Patch #2: Add several comments explaining pieces of code and BWMON, extend
   commit msg with measurements, extend help message, add new #defines to document
   some magic values, reorder bwmon clear/disable/enable operations to match
   downstream source and document this with comments, fix unit count from 1 MB
   to 65 kB.
5. Patch #4: drop opp-avg-kBps.
6. Add accumulated Rb tags.

Changes since v1
================
1. Add defconfig change.
2. Fix missing semicolon in MODULE_AUTHOR.
3. Add original downstream (msm-4.9 tree) copyrights to the driver.

Description
===========
BWMON is a data bandwidth monitor providing throughput/bandwidth over certain
interconnect links in a SoC.  It might be used to gather current bus usage and
vote for interconnect bandwidth, thus adjusting the bus speed based on actual
usage.

The work is built on top of Thara Gopinath's patches with several cleanups,
changes and simplifications.

Best regards,
Krzysztof

Krzysztof Kozlowski (4):
  dt-bindings: interconnect: qcom,sdm845-cpu-bwmon: add BWMON device
  soc: qcom: icc-bwmon: Add bandwidth monitoring driver
  arm64: defconfig: enable Qualcomm Bandwidth Monitor
  arm64: dts: qcom: sdm845: Add CPU BWMON

 .../interconnect/qcom,sdm845-cpu-bwmon.yaml   |  97 ++++
 MAINTAINERS                                   |   7 +
 arch/arm64/boot/dts/qcom/sdm845.dtsi          |  54 +++
 arch/arm64/configs/defconfig                  |   1 +
 drivers/soc/qcom/Kconfig                      |  15 +
 drivers/soc/qcom/Makefile                     |   1 +
 drivers/soc/qcom/icc-bwmon.c                  | 418 ++++++++++++++++++
 7 files changed, 593 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/interconnect/qcom,sdm845-cpu-bwmon.yaml
 create mode 100644 drivers/soc/qcom/icc-bwmon.c

-- 
2.34.1

[PATCH v3 1/4] dt-bindings: interconnect: qcom,sdm845-cpu-bwmon: add BWMON device

[Krzysztof Kozlowski]

Add bindings for the Qualcomm Bandwidth Monitor device providing
performance data on interconnects.  The bindings describe only BWMON
version 4, e.g. the instance on SDM845 between CPU and Last Level Cache
Controller.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Acked-by: Georgi Djakov <djakov@kernel.org>
---
 .../interconnect/qcom,sdm845-cpu-bwmon.yaml   | 97 +++++++++++++++++++
 1 file changed, 97 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/interconnect/qcom,sdm845-cpu-bwmon.yaml

diff --git a/Documentation/devicetree/bindings/interconnect/qcom,sdm845-cpu-bwmon.yaml b/Documentation/devicetree/bindings/interconnect/qcom,sdm845-cpu-bwmon.yaml
new file mode 100644
index 000000000000..8c82e06ee432
--- /dev/null
+++ b/Documentation/devicetree/bindings/interconnect/qcom,sdm845-cpu-bwmon.yaml
@@ -0,0 +1,97 @@
+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/interconnect/qcom,sdm845-cpu-bwmon.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Qualcomm Interconnect Bandwidth Monitor
+
+maintainers:
+  - Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
+
+description:
+  Bandwidth Monitor measures current throughput on buses between various NoC
+  fabrics and provides information when it crosses configured thresholds.
+
+properties:
+  compatible:
+    enum:
+      - qcom,sdm845-cpu-bwmon       # BWMON v4
+
+  interconnects:
+    maxItems: 2
+
+  interconnect-names:
+    items:
+      - const: ddr
+      - const: l3c
+
+  interrupts:
+    maxItems: 1
+
+  operating-points-v2: true
+  opp-table: true
+
+  reg:
+    # Currently described BWMON v4 and v5 use one register address space.
+    # BWMON v2 uses two register spaces - not yet described.
+    maxItems: 1
+
+required:
+  - compatible
+  - interconnects
+  - interconnect-names
+  - interrupts
+  - operating-points-v2
+  - opp-table
+  - reg
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/interconnect/qcom,osm-l3.h>
+    #include <dt-bindings/interconnect/qcom,sdm845.h>
+    #include <dt-bindings/interrupt-controller/arm-gic.h>
+
+    pmu@1436400 {
+        compatible = "qcom,sdm845-cpu-bwmon";
+        reg = <0x01436400 0x600>;
+
+        interrupts = <GIC_SPI 581 IRQ_TYPE_LEVEL_HIGH>;
+
+        interconnects = <&gladiator_noc MASTER_APPSS_PROC 3 &mem_noc SLAVE_EBI1 3>,
+                        <&osm_l3 MASTER_OSM_L3_APPS &osm_l3 SLAVE_OSM_L3>;
+        interconnect-names = "ddr", "l3c";
+
+        operating-points-v2 = <&cpu_bwmon_opp_table>;
+
+        cpu_bwmon_opp_table: opp-table {
+            compatible = "operating-points-v2";
+
+            opp-0 {
+                opp-peak-kBps = <800000 4800000>;
+            };
+            opp-1 {
+                opp-peak-kBps = <1804000 9216000>;
+            };
+            opp-2 {
+                opp-peak-kBps = <2188000 11980800>;
+            };
+            opp-3 {
+                opp-peak-kBps = <3072000 15052800>;
+            };
+            opp-4 {
+                opp-peak-kBps = <4068000 19353600>;
+            };
+            opp-5 {
+                opp-peak-kBps = <5412000 20889600>;
+            };
+            opp-6 {
+                opp-peak-kBps = <6220000 22425600>;
+            };
+            opp-7 {
+                opp-peak-kBps = <7216000 25497600>;
+            };
+        };
+    };
-- 
2.34.1

[PATCH v3 2/4] soc: qcom: icc-bwmon: Add bandwidth monitoring driver

[Krzysztof Kozlowski]

Bandwidth monitoring (BWMON) sits between various subsytems like CPU,
GPU, Last Level caches and memory subsystem.  The BWMON can be
configured to monitor the data throuhput between memory and other
subsytems.  The throughput is measured within specified sampling window
and is used to vote for corresponding interconnect bandwidth.

Current implementation brings support for BWMON v4, used for example on
SDM845 to measure bandwidth between CPU (gladiator_noc) and Last Level
Cache (memnoc).  Usage of this BWMON allows to remove fixed bandwidth
votes from cpufreq (CPU nodes) thus achieve high memory throughput even
with lower CPU frequencies.

Co-developed-by: Thara Gopinath <thara.gopinath@linaro.org>
Signed-off-by: Thara Gopinath <thara.gopinath@linaro.org>
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
---
 MAINTAINERS                  |   7 +
 drivers/soc/qcom/Kconfig     |  15 ++
 drivers/soc/qcom/Makefile    |   1 +
 drivers/soc/qcom/icc-bwmon.c | 418 +++++++++++++++++++++++++++++++++++
 4 files changed, 441 insertions(+)
 create mode 100644 drivers/soc/qcom/icc-bwmon.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 6157e706ed02..bc123f706256 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -16376,6 +16376,13 @@ S:	Maintained
 F:	Documentation/devicetree/bindings/i2c/i2c-qcom-cci.txt
 F:	drivers/i2c/busses/i2c-qcom-cci.c
 
+QUALCOMM INTERCONNECT BWMON DRIVER
+M:	Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
+L:	linux-arm-msm@vger.kernel.org
+S:	Maintained
+F:	Documentation/devicetree/bindings/interconnect/qcom,sdm845-cpu-bwmon.yaml
+F:	drivers/soc/qcom/icc-bwmon.c
+
 QUALCOMM IOMMU
 M:	Rob Clark <robdclark@gmail.com>
 L:	iommu@lists.linux-foundation.org
diff --git a/drivers/soc/qcom/Kconfig b/drivers/soc/qcom/Kconfig
index e718b8735444..35c5192dcfc7 100644
--- a/drivers/soc/qcom/Kconfig
+++ b/drivers/soc/qcom/Kconfig
@@ -228,4 +228,19 @@ config QCOM_APR
 	  application processor and QDSP6. APR is
 	  used by audio driver to configure QDSP6
 	  ASM, ADM and AFE modules.
+
+config QCOM_ICC_BWMON
+	tristate "QCOM Interconnect Bandwidth Monitor driver"
+	depends on ARCH_QCOM || COMPILE_TEST
+	select PM_OPP
+	help
+	  Sets up driver monitoring bandwidth on various interconnects and
+	  based on that voting for interconnect bandwidth, adjusting their
+	  speed to current demand.
+	  Current implementation brings support for BWMON v4, used for example
+	  on SDM845 to measure bandwidth between CPU (gladiator_noc) and Last
+	  Level Cache (memnoc).  Usage of this BWMON allows to remove fixed
+	  bandwidth votes from cpufreq (CPU nodes) thus achieve high memory
+	  throughput even with lower CPU frequencies.
+
 endmenu
diff --git a/drivers/soc/qcom/Makefile b/drivers/soc/qcom/Makefile
index 70d5de69fd7b..d66604aff2b0 100644
--- a/drivers/soc/qcom/Makefile
+++ b/drivers/soc/qcom/Makefile
@@ -28,3 +28,4 @@ obj-$(CONFIG_QCOM_LLCC) += llcc-qcom.o
 obj-$(CONFIG_QCOM_RPMHPD) += rpmhpd.o
 obj-$(CONFIG_QCOM_RPMPD) += rpmpd.o
 obj-$(CONFIG_QCOM_KRYO_L2_ACCESSORS) +=	kryo-l2-accessors.o
+obj-$(CONFIG_QCOM_ICC_BWMON)	+= icc-bwmon.o
diff --git a/drivers/soc/qcom/icc-bwmon.c b/drivers/soc/qcom/icc-bwmon.c
new file mode 100644
index 000000000000..7feb27f49291
--- /dev/null
+++ b/drivers/soc/qcom/icc-bwmon.c
@@ -0,0 +1,418 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2014-2018, The Linux Foundation. All rights reserved.
+ * Copyright (C) 2021-2022 Linaro Ltd
+ * Author: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>, based on
+ *         previous work of Thara Gopinath and msm-4.9 downstream sources.
+ */
+#include <linux/interconnect.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/pm_opp.h>
+#include <linux/sizes.h>
+
+/*
+ * The BWMON samples data throughput within 'sample_ms' time. With three
+ * configurable thresholds (Low, Medium and High) gives four windows (called
+ * zones) of current bandwidth:
+ *
+ * Zone 0: byte count < THRES_LO
+ * Zone 1: THRES_LO < byte count < THRES_MED
+ * Zone 2: THRES_MED < byte count < THRES_HIGH
+ * Zone 3: THRES_HIGH < byte count
+ *
+ * Zones 0 and 2 are not used by this driver.
+ */
+
+/* Internal sampling clock frequency */
+#define HW_TIMER_HZ				19200000
+
+#define BWMON_GLOBAL_IRQ_STATUS			0x0
+#define BWMON_GLOBAL_IRQ_CLEAR			0x8
+#define BWMON_GLOBAL_IRQ_ENABLE			0xc
+#define BWMON_GLOBAL_IRQ_ENABLE_ENABLE		BIT(0)
+
+#define BWMON_IRQ_STATUS			0x100
+#define BWMON_IRQ_STATUS_ZONE_SHIFT		4
+#define BWMON_IRQ_CLEAR				0x108
+#define BWMON_IRQ_ENABLE			0x10c
+#define BWMON_IRQ_ENABLE_ZONE1_SHIFT		5
+#define BWMON_IRQ_ENABLE_ZONE2_SHIFT		6
+#define BWMON_IRQ_ENABLE_ZONE3_SHIFT		7
+#define BWMON_IRQ_ENABLE_MASK			(BIT(BWMON_IRQ_ENABLE_ZONE1_SHIFT) | \
+						 BIT(BWMON_IRQ_ENABLE_ZONE3_SHIFT))
+
+#define BWMON_ENABLE				0x2a0
+#define BWMON_ENABLE_ENABLE			BIT(0)
+
+#define BWMON_CLEAR				0x2a4
+#define BWMON_CLEAR_CLEAR			BIT(0)
+
+#define BWMON_SAMPLE_WINDOW			0x2a8
+#define BWMON_THRESHOLD_HIGH			0x2ac
+#define BWMON_THRESHOLD_MED			0x2b0
+#define BWMON_THRESHOLD_LOW			0x2b4
+
+#define BWMON_ZONE_ACTIONS			0x2b8
+/*
+ * Actions to perform on some zone 'z' when current zone hits the threshold:
+ * Increment counter of zone 'z'
+ */
+#define BWMON_ZONE_ACTIONS_INCREMENT(z)		(0x2 << ((z) * 2))
+/* Clear counter of zone 'z' */
+#define BWMON_ZONE_ACTIONS_CLEAR(z)		(0x1 << ((z) * 2))
+
+/* Zone 0 threshold hit: Clear zone count */
+#define BWMON_ZONE_ACTIONS_ZONE0		(BWMON_ZONE_ACTIONS_CLEAR(0))
+
+/* Zone 1 threshold hit: Increment zone count & clear lower zones */
+#define BWMON_ZONE_ACTIONS_ZONE1		(BWMON_ZONE_ACTIONS_INCREMENT(1) | \
+						 BWMON_ZONE_ACTIONS_CLEAR(0))
+
+/* Zone 2 threshold hit: Increment zone count & clear lower zones */
+#define BWMON_ZONE_ACTIONS_ZONE2		(BWMON_ZONE_ACTIONS_INCREMENT(2) | \
+						 BWMON_ZONE_ACTIONS_CLEAR(1) | \
+						 BWMON_ZONE_ACTIONS_CLEAR(0))
+
+/* Zone 3 threshold hit: Increment zone count & clear lower zones */
+#define BWMON_ZONE_ACTIONS_ZONE3		(BWMON_ZONE_ACTIONS_INCREMENT(3) | \
+						 BWMON_ZONE_ACTIONS_CLEAR(2) | \
+						 BWMON_ZONE_ACTIONS_CLEAR(1) | \
+						 BWMON_ZONE_ACTIONS_CLEAR(0))
+/* Value for BWMON_ZONE_ACTIONS */
+#define BWMON_ZONE_ACTIONS_DEFAULT		(BWMON_ZONE_ACTIONS_ZONE0 | \
+						 BWMON_ZONE_ACTIONS_ZONE1 << 8 | \
+						 BWMON_ZONE_ACTIONS_ZONE2 << 16 | \
+						 BWMON_ZONE_ACTIONS_ZONE3 << 24)
+
+/*
+ * There is no clear documentation/explanation of BWMON_THRESHOLD_COUNT
+ * register. Based on observations, this is number of times one threshold has to
+ * be reached, to trigger interrupt in given zone.
+ *
+ * 0xff are maximum values meant to ignore the zones 0 and 2.
+ */
+#define BWMON_THRESHOLD_COUNT			0x2bc
+#define BWMON_THRESHOLD_COUNT_ZONE1_SHIFT	8
+#define BWMON_THRESHOLD_COUNT_ZONE2_SHIFT	16
+#define BWMON_THRESHOLD_COUNT_ZONE3_SHIFT	24
+#define BWMON_THRESHOLD_COUNT_ZONE0_DEFAULT	0xff
+#define BWMON_THRESHOLD_COUNT_ZONE2_DEFAULT	0xff
+
+/* BWMONv4 count registers use count unit of 64 kB */
+#define BWMON_COUNT_UNIT_KB			64
+#define BWMON_ZONE_COUNT			0x2d8
+#define BWMON_ZONE_MAX(zone)			(0x2e0 + 4 * (zone))
+
+struct icc_bwmon_data {
+	unsigned int sample_ms;
+	unsigned int default_highbw_kbps;
+	unsigned int default_medbw_kbps;
+	unsigned int default_lowbw_kbps;
+	u8 zone1_thres_count;
+	u8 zone3_thres_count;
+};
+
+struct icc_bwmon {
+	struct device *dev;
+	void __iomem *base;
+	int irq;
+
+	unsigned int default_lowbw_kbps;
+	unsigned int sample_ms;
+	unsigned int max_bw_kbps;
+	unsigned int min_bw_kbps;
+	unsigned int target_kbps;
+	unsigned int current_kbps;
+};
+
+static void bwmon_clear(struct icc_bwmon *bwmon)
+{
+	/*
+	 * Clear counters. The order and barriers are
+	 * important. Quoting downstream Qualcomm msm-4.9 tree:
+	 *
+	 * The counter clear and IRQ clear bits are not in the same 4KB
+	 * region. So, we need to make sure the counter clear is completed
+	 * before we try to clear the IRQ or do any other counter operations.
+	 */
+	writel(BWMON_CLEAR_CLEAR, bwmon->base + BWMON_CLEAR);
+
+	/*
+	 * Clear zone and global interrupts. The order and barriers are
+	 * important. Quoting downstream Qualcomm msm-4.9 tree:
+	 *
+	 * Synchronize the local interrupt clear in mon_irq_clear()
+	 * with the global interrupt clear here. Otherwise, the CPU
+	 * may reorder the two writes and clear the global interrupt
+	 * before the local interrupt, causing the global interrupt
+	 * to be retriggered by the local interrupt still being high.
+	 *
+	 * Similarly, because the global registers are in a different
+	 * region than the local registers, we need to ensure any register
+	 * writes to enable the monitor after this call are ordered with the
+	 * clearing here so that local writes don't happen before the
+	 * interrupt is cleared.
+	 */
+	writel(BWMON_IRQ_ENABLE_MASK, bwmon->base + BWMON_IRQ_CLEAR);
+	writel(BIT(0), bwmon->base + BWMON_GLOBAL_IRQ_CLEAR);
+}
+
+static void bwmon_disable(struct icc_bwmon *bwmon)
+{
+	/* Disable interrupts. Strict ordering, see bwmon_clear(). */
+	writel(0x0, bwmon->base + BWMON_GLOBAL_IRQ_ENABLE);
+	writel(0x0, bwmon->base + BWMON_IRQ_ENABLE);
+
+	/*
+	 * Disable bwmon. Must happen before bwmon_clear() to avoid spurious
+	 * IRQ.
+	 */
+	writel(0x0, bwmon->base + BWMON_ENABLE);
+}
+
+static void bwmon_enable(struct icc_bwmon *bwmon, unsigned int irq_enable)
+{
+	/* Enable interrupts */
+	writel(BWMON_GLOBAL_IRQ_ENABLE_ENABLE,
+	       bwmon->base + BWMON_GLOBAL_IRQ_ENABLE);
+	writel(irq_enable, bwmon->base + BWMON_IRQ_ENABLE);
+
+	/* Enable bwmon */
+	writel(BWMON_ENABLE_ENABLE, bwmon->base + BWMON_ENABLE);
+}
+
+static unsigned int bwmon_kbps_to_count(unsigned int kbps)
+{
+	return kbps / BWMON_COUNT_UNIT_KB;
+}
+
+static void bwmon_set_threshold(struct icc_bwmon *bwmon, unsigned int reg,
+				unsigned int kbps)
+{
+	unsigned int thres;
+
+	thres = mult_frac(bwmon_kbps_to_count(kbps), bwmon->sample_ms,
+			  MSEC_PER_SEC);
+	writel_relaxed(thres, bwmon->base + reg);
+}
+
+static void bwmon_start(struct icc_bwmon *bwmon,
+			const struct icc_bwmon_data *data)
+{
+	unsigned int thres_count, irq_enable;
+	int window;
+
+	bwmon_clear(bwmon);
+
+	window = mult_frac(bwmon->sample_ms, HW_TIMER_HZ, MSEC_PER_SEC);
+	/* Maximum sampling window: 0xfffff */
+	writel_relaxed(window, bwmon->base + BWMON_SAMPLE_WINDOW);
+
+	bwmon_set_threshold(bwmon, BWMON_THRESHOLD_HIGH,
+			    data->default_highbw_kbps);
+	bwmon_set_threshold(bwmon, BWMON_THRESHOLD_MED,
+			    data->default_medbw_kbps);
+	bwmon_set_threshold(bwmon, BWMON_THRESHOLD_LOW,
+			    data->default_lowbw_kbps);
+
+	thres_count = data->zone3_thres_count << BWMON_THRESHOLD_COUNT_ZONE3_SHIFT |
+		      BWMON_THRESHOLD_COUNT_ZONE2_DEFAULT << BWMON_THRESHOLD_COUNT_ZONE2_SHIFT |
+		      data->zone1_thres_count << BWMON_THRESHOLD_COUNT_ZONE1_SHIFT |
+		      BWMON_THRESHOLD_COUNT_ZONE0_DEFAULT;
+	writel_relaxed(thres_count, bwmon->base + BWMON_THRESHOLD_COUNT);
+	writel_relaxed(BWMON_ZONE_ACTIONS_DEFAULT,
+		       bwmon->base + BWMON_ZONE_ACTIONS);
+
+	/* Write barriers in bwmon_clear() */
+	irq_enable = BIT(BWMON_IRQ_ENABLE_ZONE1_SHIFT) |
+		     BIT(BWMON_IRQ_ENABLE_ZONE3_SHIFT);
+	bwmon_clear(bwmon);
+	bwmon_enable(bwmon, BWMON_IRQ_ENABLE_MASK);
+}
+
+static irqreturn_t bwmon_intr(int irq, void *dev_id)
+{
+	struct icc_bwmon *bwmon = dev_id;
+	unsigned int status, max;
+	int zone;
+
+	status = readl(bwmon->base + BWMON_IRQ_STATUS);
+	status &= BWMON_IRQ_ENABLE_MASK;
+	if (!status) {
+		/*
+		 * Only zone 1 and zone 3 interrupts are enabled but zone 2
+		 * threshold could be hit and trigger interrupt even if not
+		 * enabled.
+		 * Such spurious interrupt might come with valuable max count or
+		 * not, so solution would be to always check all
+		 * BWMON_ZONE_MAX() registers to find the highest value.
+		 * Such case is currently ignored.
+		 */
+		return IRQ_NONE;
+	}
+
+	bwmon_disable(bwmon);
+
+	zone = get_bitmask_order(status >> BWMON_IRQ_STATUS_ZONE_SHIFT) - 1;
+	/*
+	 * Zone max bytes count register returns count units within sampling
+	 * window.  Downstream kernel for BWMONv4 (called BWMON type 2 in
+	 * downstream) always increments the max bytes count by one.
+	 */
+	max = readl(bwmon->base + BWMON_ZONE_MAX(zone)) + 1;
+	max *= BWMON_COUNT_UNIT_KB;
+	bwmon->target_kbps = mult_frac(max, MSEC_PER_SEC, bwmon->sample_ms);
+
+	return IRQ_WAKE_THREAD;
+}
+
+static irqreturn_t bwmon_intr_thread(int irq, void *dev_id)
+{
+	struct icc_bwmon *bwmon = dev_id;
+	unsigned int irq_enable = 0;
+	struct dev_pm_opp *opp, *target_opp;
+	unsigned int bw_kbps, up_kbps, down_kbps;
+
+	bw_kbps = bwmon->target_kbps;
+
+	target_opp = dev_pm_opp_find_bw_ceil(bwmon->dev, &bw_kbps, 0);
+	if (IS_ERR(target_opp) && PTR_ERR(target_opp) == -ERANGE)
+		target_opp = dev_pm_opp_find_bw_floor(bwmon->dev, &bw_kbps, 0);
+
+	bwmon->target_kbps = bw_kbps;
+
+	bw_kbps--;
+	opp = dev_pm_opp_find_bw_floor(bwmon->dev, &bw_kbps, 0);
+	if (IS_ERR(opp) && PTR_ERR(opp) == -ERANGE)
+		down_kbps = bwmon->target_kbps;
+	else
+		down_kbps = bw_kbps;
+
+	up_kbps = bwmon->target_kbps + 1;
+
+	if (bwmon->target_kbps >= bwmon->max_bw_kbps)
+		irq_enable = BIT(BWMON_IRQ_ENABLE_ZONE1_SHIFT);
+	else if (bwmon->target_kbps <= bwmon->min_bw_kbps)
+		irq_enable = BIT(BWMON_IRQ_ENABLE_ZONE3_SHIFT);
+	else
+		irq_enable = BWMON_IRQ_ENABLE_MASK;
+
+	bwmon_set_threshold(bwmon, BWMON_THRESHOLD_HIGH, up_kbps);
+	bwmon_set_threshold(bwmon, BWMON_THRESHOLD_MED, down_kbps);
+	bwmon_clear(bwmon);
+	bwmon_enable(bwmon, irq_enable);
+
+	if (bwmon->target_kbps == bwmon->current_kbps)
+		goto out;
+
+	dev_pm_opp_set_opp(bwmon->dev, target_opp);
+	bwmon->current_kbps = bwmon->target_kbps;
+
+out:
+	dev_pm_opp_put(target_opp);
+	if (!IS_ERR(opp))
+		dev_pm_opp_put(opp);
+
+	return IRQ_HANDLED;
+}
+
+static int bwmon_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct dev_pm_opp *opp;
+	struct icc_bwmon *bwmon;
+	const struct icc_bwmon_data *data;
+	int ret;
+
+	bwmon = devm_kzalloc(dev, sizeof(*bwmon), GFP_KERNEL);
+	if (!bwmon)
+		return -ENOMEM;
+
+	data = of_device_get_match_data(dev);
+
+	bwmon->base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(bwmon->base)) {
+		dev_err(dev, "failed to map bwmon registers\n");
+		return PTR_ERR(bwmon->base);
+	}
+
+	bwmon->irq = platform_get_irq(pdev, 0);
+	if (bwmon->irq < 0) {
+		dev_err(dev, "failed to acquire bwmon IRQ\n");
+		return bwmon->irq;
+	}
+
+	ret = devm_pm_opp_of_add_table(dev);
+	if (ret)
+		return dev_err_probe(dev, ret, "failed to add OPP table\n");
+
+	bwmon->max_bw_kbps = UINT_MAX;
+	opp = dev_pm_opp_find_bw_floor(dev, &bwmon->max_bw_kbps, 0);
+	if (IS_ERR(opp))
+		return dev_err_probe(dev, ret, "failed to find max peak bandwidth\n");
+
+	bwmon->min_bw_kbps = 0;
+	opp = dev_pm_opp_find_bw_ceil(dev, &bwmon->min_bw_kbps, 0);
+	if (IS_ERR(opp))
+		return dev_err_probe(dev, ret, "failed to find min peak bandwidth\n");
+
+	bwmon->sample_ms = data->sample_ms;
+	bwmon->default_lowbw_kbps = data->default_lowbw_kbps;
+	bwmon->dev = dev;
+
+	bwmon_disable(bwmon);
+	ret = devm_request_threaded_irq(dev, bwmon->irq, bwmon_intr,
+					bwmon_intr_thread,
+					IRQF_ONESHOT, dev_name(dev), bwmon);
+	if (ret)
+		return dev_err_probe(dev, ret, "failed to request IRQ\n");
+
+	platform_set_drvdata(pdev, bwmon);
+	bwmon_start(bwmon, data);
+
+	return 0;
+}
+
+static int bwmon_remove(struct platform_device *pdev)
+{
+	struct icc_bwmon *bwmon = platform_get_drvdata(pdev);
+
+	bwmon_disable(bwmon);
+
+	return 0;
+}
+
+/* BWMON v4 */
+static const struct icc_bwmon_data sdm845_bwmon_data = {
+	.sample_ms = 4,
+	.default_highbw_kbps = 4800 * 1024, /* 4.8 GBps */
+	.default_medbw_kbps = 512 * 1024, /* 512 MBps */
+	.default_lowbw_kbps = 0,
+	.zone1_thres_count = 16,
+	.zone3_thres_count = 1,
+};
+
+static const struct of_device_id bwmon_of_match[] = {
+	{ .compatible = "qcom,sdm845-cpu-bwmon", .data = &sdm845_bwmon_data },
+	{}
+};
+MODULE_DEVICE_TABLE(of, bwmon_of_match);
+
+static struct platform_driver bwmon_driver = {
+	.probe = bwmon_probe,
+	.remove = bwmon_remove,
+	.driver = {
+		.name = "qcom-bwmon",
+		.of_match_table = bwmon_of_match,
+	},
+};
+module_platform_driver(bwmon_driver);
+
+MODULE_AUTHOR("Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>");
+MODULE_DESCRIPTION("QCOM BWMON driver");
+MODULE_LICENSE("GPL");
-- 
2.34.1

[PATCH v3 3/4] arm64: defconfig: enable Qualcomm Bandwidth Monitor

[Krzysztof Kozlowski]

Enable the Qualcomm Bandwidth Monitor to allow scaling interconnects
depending on bandwidth usage between CPU and memory.  This is used
already on Qualcomm SDM845 SoC.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
---
 arch/arm64/configs/defconfig | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/arm64/configs/defconfig b/arch/arm64/configs/defconfig
index 6906b83f5e45..6edbcfd3f4ca 100644
--- a/arch/arm64/configs/defconfig
+++ b/arch/arm64/configs/defconfig
@@ -1096,6 +1096,7 @@ CONFIG_QCOM_SOCINFO=m
 CONFIG_QCOM_STATS=m
 CONFIG_QCOM_WCNSS_CTRL=m
 CONFIG_QCOM_APR=m
+CONFIG_QCOM_ICC_BWMON=m
 CONFIG_ARCH_R8A77995=y
 CONFIG_ARCH_R8A77990=y
 CONFIG_ARCH_R8A77950=y
-- 
2.34.1

[PATCH v3 4/4] arm64: dts: qcom: sdm845: Add CPU BWMON

[Krzysztof Kozlowski]

Add device node for CPU-memory BWMON device (bandwidth monitoring) on
SDM845 measuring bandwidth between CPU (gladiator_noc) and Last Level
Cache (memnoc).  Usage of this BWMON allows to remove fixed bandwidth
votes from cpufreq (CPU nodes) thus achieve high memory throughput even
with lower CPU frequencies.

Performance impact (SDM845-MTP RB3 board, linux next-20220422):
1. No noticeable impact when running with schedutil or performance
   governors.

2. When comparing to customized kernel with synced interconnects and
   without bandwidth votes from CPU freq, the sysbench memory tests
   show significant improvement with bwmon for blocksizes past the L3
   cache.  The results for such superficial comparison:

sysbench memory test, results in MB/s (higher is better)
 bs kB |  type |    V  | V+no bw votes | bwmon | benefit %
     1 | W/seq | 14795 |          4816 |  4985 |      3.5%
    64 | W/seq | 41987 |         10334 | 10433 |      1.0%
  4096 | W/seq | 29768 |          8728 | 32007 |    266.7%
 65536 | W/seq | 17711 |          4846 | 18399 |    279.6%
262144 | W/seq | 16112 |          4538 | 17429 |    284.1%
    64 | R/seq | 61202 |         67092 | 66804 |     -0.4%
  4096 | R/seq | 23871 |          5458 | 24307 |    345.4%
 65536 | R/seq | 18554 |          4240 | 18685 |    340.7%
262144 | R/seq | 17524 |          4207 | 17774 |    322.4%
    64 | W/rnd |  2663 |          1098 |  1119 |      1.9%
 65536 | W/rnd |   600 |           316 |   610 |     92.7%
    64 | R/rnd |  4915 |          4784 |  4594 |     -4.0%
 65536 | R/rnd |   664 |           281 |   678 |    140.7%

Legend:
bs kB: block size in KB (small block size means only L1-3 caches are
      used
type: R - read, W - write, seq - sequential, rnd - random
V: vanilla (next-20220422)
V + no bw votes: vanilla without bandwidth votes from CPU freq
bwmon: bwmon without bandwidth votes from CPU freq
benefit %: difference between vanilla without bandwidth votes and bwmon
           (higher is better)

Co-developed-by: Thara Gopinath <thara.gopinath@linaro.org>
Signed-off-by: Thara Gopinath <thara.gopinath@linaro.org>
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
---
 arch/arm64/boot/dts/qcom/sdm845.dtsi | 54 ++++++++++++++++++++++++++++
 1 file changed, 54 insertions(+)

diff --git a/arch/arm64/boot/dts/qcom/sdm845.dtsi b/arch/arm64/boot/dts/qcom/sdm845.dtsi
index 83e8b63f0910..adffb9c70566 100644
--- a/arch/arm64/boot/dts/qcom/sdm845.dtsi
+++ b/arch/arm64/boot/dts/qcom/sdm845.dtsi
@@ -2026,6 +2026,60 @@ llcc: system-cache-controller@1100000 {
 			interrupts = <GIC_SPI 582 IRQ_TYPE_LEVEL_HIGH>;
 		};
 
+		pmu@1436400 {
+			compatible = "qcom,sdm845-cpu-bwmon";
+			reg = <0 0x01436400 0 0x600>;
+
+			interrupts = <GIC_SPI 581 IRQ_TYPE_LEVEL_HIGH>;
+
+			interconnects = <&gladiator_noc MASTER_APPSS_PROC 3 &mem_noc SLAVE_EBI1 3>,
+					<&osm_l3 MASTER_OSM_L3_APPS &osm_l3 SLAVE_OSM_L3>;
+			interconnect-names = "ddr", "l3c";
+
+			operating-points-v2 = <&cpu_bwmon_opp_table>;
+
+			cpu_bwmon_opp_table: opp-table {
+				compatible = "operating-points-v2";
+
+				/*
+				 * The interconnect paths bandwidths taken from
+				 * cpu4_opp_table bandwidth.
+				 * They also match different tables from
+				 * msm-4.9 downstream kernel:
+				 *  - the gladiator_noc-mem_noc from bandwidth
+				 *    table of qcom,llccbw (property qcom,bw-tbl);
+				 *    bus width: 4 bytes;
+				 *  - the OSM L3 from bandwidth table of
+				 *    qcom,cpu4-l3lat-mon (qcom,core-dev-table);
+				 *    bus width: 16 bytes;
+				 */
+				opp-0 {
+					opp-peak-kBps = <800000 4800000>;
+				};
+				opp-1 {
+					opp-peak-kBps = <1804000 9216000>;
+				};
+				opp-2 {
+					opp-peak-kBps = <2188000 11980800>;
+				};
+				opp-3 {
+					opp-peak-kBps = <3072000 15052800>;
+				};
+				opp-4 {
+					opp-peak-kBps = <4068000 19353600>;
+				};
+				opp-5 {
+					opp-peak-kBps = <5412000 20889600>;
+				};
+				opp-6 {
+					opp-peak-kBps = <6220000 22425600>;
+				};
+				opp-7 {
+					opp-peak-kBps = <7216000 25497600>;
+				};
+			};
+		};
+
 		pcie0: pci@1c00000 {
 			compatible = "qcom,pcie-sdm845";
 			reg = <0 0x01c00000 0 0x2000>,
-- 
2.34.1

Re: [PATCH v3 2/4] soc: qcom: icc-bwmon: Add bandwidth monitoring driver

[Krzysztof Kozlowski]

On 31/05/2022 12:51, Krzysztof Kozlowski wrote:
> +	window = mult_frac(bwmon->sample_ms, HW_TIMER_HZ, MSEC_PER_SEC);
> +	/* Maximum sampling window: 0xfffff */
> +	writel_relaxed(window, bwmon->base + BWMON_SAMPLE_WINDOW);
> +
> +	bwmon_set_threshold(bwmon, BWMON_THRESHOLD_HIGH,
> +			    data->default_highbw_kbps);
> +	bwmon_set_threshold(bwmon, BWMON_THRESHOLD_MED,
> +			    data->default_medbw_kbps);
> +	bwmon_set_threshold(bwmon, BWMON_THRESHOLD_LOW,
> +			    data->default_lowbw_kbps);
> +
> +	thres_count = data->zone3_thres_count << BWMON_THRESHOLD_COUNT_ZONE3_SHIFT |
> +		      BWMON_THRESHOLD_COUNT_ZONE2_DEFAULT << BWMON_THRESHOLD_COUNT_ZONE2_SHIFT |
> +		      data->zone1_thres_count << BWMON_THRESHOLD_COUNT_ZONE1_SHIFT |
> +		      BWMON_THRESHOLD_COUNT_ZONE0_DEFAULT;
> +	writel_relaxed(thres_count, bwmon->base + BWMON_THRESHOLD_COUNT);
> +	writel_relaxed(BWMON_ZONE_ACTIONS_DEFAULT,
> +		       bwmon->base + BWMON_ZONE_ACTIONS);
> +
> +	/* Write barriers in bwmon_clear() */
> +	irq_enable = BIT(BWMON_IRQ_ENABLE_ZONE1_SHIFT) |
> +		     BIT(BWMON_IRQ_ENABLE_ZONE3_SHIFT);

Unusued variable, I will send a v4.



Best regards,
Krzysztof