PM / devfreq: Add MSM BIMC bwmon support for bw_hwmon governor

The BIMC bwmon device supports monitoring read/write traffic from each BIMC
master port. It also has the capability to raise an IRQ when the traffic
count exceeds a programmable threshold. This allows for it to be used with
the bw_hwmon governor to scale the BW requests from each BIMC master.

Change-Id: Ie8a1471226411e23954ed556292186a5a864ddc1
Signed-off-by: Saravana Kannan <skannan@codeaurora.org>

Documentation/devicetree/bindings/devfreq/bimc-bwmon.txt

@@ -0,0 +1,25 @@
+MSM BIMC bandwidth monitor device
+
+bimc-bwmon is a device that represents the MSM BIMC bandwidth monitors that
+can be used to measure the bandwidth of read/write traffic from the BIMC
+master ports. For example, the CPU subsystem sits on one BIMC master port.
+
+Required properties:
+- compatible:		Must be "qcom,bimc-bwmon"
+- reg:			Pairs of physical base addresses and region sizes of
+			memory mapped registers.
+- reg-names:		Names of the bases for the above registers. Expected
+			bases are: "base", "global_base"
+- interrupts:		Lists the threshold IRQ.
+- qcom,mport:		The hardware master port that this device can monitor
+- qcom,target-dev:	The DT device that corresponds to this master port
+
+Example:
+	qcom,cpu-bwmon {
+		compatible = "qcom,bimc-bwmon";
+		reg = <0xfc388000 0x300>, <0xfc381000 0x200>;
+		reg-names = "base", "global_base";
+		interrupts = <0 183 1>;
+		qcom,mport = <0>;
+		qcom,target-dev = <&cpubw>;
+	};

drivers/devfreq/Kconfig

@@ -73,6 +73,15 @@ config DEVFREQ_GOV_PASSIVE
 	  through sysfs entries. The passive governor recommends that
 	  devfreq device uses the OPP table to get the frequency/voltage.
 
+config QCOM_BIMC_BWMON
+	tristate "QCOM BIMC Bandwidth monitor hardware"
+	depends on ARCH_QCOM
+	help
+	  The BIMC Bandwidth monitor hardware allows for monitoring the
+	  traffic coming from each master port connected to the BIMC. It also
+	  has the capability to raise an IRQ when the count exceeds a
+	  programmable limit.
+
 config DEVFREQ_GOV_QCOM_BW_HWMON
 	tristate "HW monitor based governor for device BW"
 	depends on QCOM_BIMC_BWMON

drivers/devfreq/Makefile

@@ -6,6 +6,7 @@ obj-$(CONFIG_DEVFREQ_GOV_PERFORMANCE)	+= governor_performance.o
 obj-$(CONFIG_DEVFREQ_GOV_POWERSAVE)	+= governor_powersave.o
 obj-$(CONFIG_DEVFREQ_GOV_USERSPACE)	+= governor_userspace.o
 obj-$(CONFIG_DEVFREQ_GOV_PASSIVE)	+= governor_passive.o
+obj-$(CONFIG_QCOM_BIMC_BWMON)		+= bimc-bwmon.o
 obj-$(CONFIG_DEVFREQ_GOV_QCOM_BW_HWMON)	+= governor_bw_hwmon.o
 obj-$(CONFIG_DEVFREQ_GOV_QCOM_CACHE_HWMON)	+= governor_cache_hwmon.o
 

drivers/devfreq/bimc-bwmon.c

@@ -0,0 +1,328 @@
+/*
+ * Copyright (c) 2014, The Linux Foundation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#define pr_fmt(fmt) "bimc-bwmon: " fmt
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/errno.h>
+#include <linux/interrupt.h>
+#include <linux/platform_device.h>
+#include <linux/of.h>
+#include <linux/spinlock.h>
+#include "governor_bw_hwmon.h"
+
+#define GLB_INT_STATUS(m)	((m)->global_base + 0x100)
+#define GLB_INT_CLR(m)		((m)->global_base + 0x108)
+#define	GLB_INT_EN(m)		((m)->global_base + 0x10C)
+#define MON_INT_STATUS(m)	((m)->base + 0x100)
+#define MON_INT_CLR(m)		((m)->base + 0x108)
+#define	MON_INT_EN(m)		((m)->base + 0x10C)
+#define	MON_EN(m)		((m)->base + 0x280)
+#define MON_CLEAR(m)		((m)->base + 0x284)
+#define MON_CNT(m)		((m)->base + 0x288)
+#define MON_THRES(m)		((m)->base + 0x290)
+#define MON_MASK(m)		((m)->base + 0x298)
+#define MON_MATCH(m)		((m)->base + 0x29C)
+
+struct bwmon {
+	void __iomem *base;
+	void __iomem *global_base;
+	unsigned int mport;
+	unsigned int irq;
+	struct device *dev;
+	struct bw_hwmon hw;
+};
+
+#define to_bwmon(ptr)		container_of(ptr, struct bwmon, hw)
+
+static DEFINE_SPINLOCK(glb_lock);
+static void mon_enable(struct bwmon *m)
+{
+	writel_relaxed(0x1, MON_EN(m));
+}
+
+static void mon_disable(struct bwmon *m)
+{
+	writel_relaxed(0x0, MON_EN(m));
+}
+
+static void mon_clear(struct bwmon *m)
+{
+	writel_relaxed(0x1, MON_CLEAR(m));
+	/*
+	 * 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.
+	 */
+	mb();
+}
+
+static void mon_irq_enable(struct bwmon *m)
+{
+	u32 val;
+
+	spin_lock(&glb_lock);
+	val = readl_relaxed(GLB_INT_EN(m));
+	val |= 1 << m->mport;
+	writel_relaxed(val, GLB_INT_EN(m));
+	spin_unlock(&glb_lock);
+
+	val = readl_relaxed(MON_INT_EN(m));
+	val |= 0x1;
+	writel_relaxed(val, MON_INT_EN(m));
+}
+
+static void mon_irq_disable(struct bwmon *m)
+{
+	u32 val;
+
+	spin_lock(&glb_lock);
+	val = readl_relaxed(GLB_INT_EN(m));
+	val &= ~(1 << m->mport);
+	writel_relaxed(val, GLB_INT_EN(m));
+	spin_unlock(&glb_lock);
+
+	val = readl_relaxed(MON_INT_EN(m));
+	val &= ~0x1;
+	writel_relaxed(val, MON_INT_EN(m));
+}
+
+static int mon_irq_status(struct bwmon *m)
+{
+	u32 mval;
+
+	mval = readl_relaxed(MON_INT_STATUS(m));
+
+	dev_dbg(m->dev, "IRQ status p:%x, g:%x\n", mval,
+			readl_relaxed(GLB_INT_STATUS(m)));
+
+	return mval & 0x1;
+}
+
+static void mon_irq_clear(struct bwmon *m)
+{
+	writel_relaxed(0x1, MON_INT_CLR(m));
+	mb();
+	writel_relaxed(1 << m->mport, GLB_INT_CLR(m));
+	mb();
+}
+
+static void mon_set_limit(struct bwmon *m, u32 count)
+{
+	writel_relaxed(count, MON_THRES(m));
+	dev_dbg(m->dev, "Thres: %08x\n", count);
+}
+
+static u32 mon_get_limit(struct bwmon *m)
+{
+	return readl_relaxed(MON_THRES(m));
+}
+
+static unsigned long mon_get_count(struct bwmon *m)
+{
+	unsigned long count;
+
+	count = readl_relaxed(MON_CNT(m));
+	dev_dbg(m->dev, "Counter: %08lx\n", count);
+	if (mon_irq_status(m))
+		count += mon_get_limit(m);
+	dev_dbg(m->dev, "Actual Count: %08lx\n", count);
+
+	return count;
+}
+
+/* ********** CPUBW specific code  ********** */
+
+/* Returns MBps of read/writes for the sampling window. */
+static unsigned int bytes_to_mbps(long long bytes, unsigned int us)
+{
+	bytes *= USEC_PER_SEC;
+	do_div(bytes, us);
+	bytes = DIV_ROUND_UP_ULL(bytes, SZ_1M);
+	return bytes;
+}
+
+static unsigned int mbps_to_bytes(unsigned long mbps, unsigned int ms,
+				  unsigned int tolerance_percent)
+{
+	mbps *= (100 + tolerance_percent) * ms;
+	mbps /= 100;
+	mbps = DIV_ROUND_UP(mbps, MSEC_PER_SEC);
+	mbps *= SZ_1M;
+	return mbps;
+}
+
+static unsigned long meas_bw_and_set_irq(struct bw_hwmon *hw,
+					 unsigned int tol, unsigned int us)
+{
+	unsigned long mbps;
+	u32 limit;
+	unsigned int sample_ms = hw->df->profile->polling_ms;
+	struct bwmon *m = to_bwmon(hw);
+
+	mon_disable(m);
+
+	mbps = mon_get_count(m);
+	mbps = bytes_to_mbps(mbps, us);
+	/*
+	 * The fudging of mbps when calculating limit is to workaround a HW
+	 * design issue. Needs further tuning.
+	 */
+	limit = mbps_to_bytes(max(mbps, 400UL), sample_ms, tol);
+	mon_set_limit(m, limit);
+
+	mon_clear(m);
+	mon_irq_clear(m);
+	mon_enable(m);
+
+	dev_dbg(m->dev, "MBps = %lu\n", mbps);
+	return mbps;
+}
+
+static irqreturn_t bwmon_intr_handler(int irq, void *dev)
+{
+	struct bwmon *m = dev;
+	if (mon_irq_status(m)) {
+		update_bw_hwmon(&m->hw);
+		return IRQ_HANDLED;
+	}
+
+	return IRQ_NONE;
+}
+
+static int start_bw_hwmon(struct bw_hwmon *hw, unsigned long mbps)
+{
+	struct bwmon *m = to_bwmon(hw);
+	u32 limit;
+	int ret;
+
+	ret = request_threaded_irq(m->irq, NULL, bwmon_intr_handler,
+				  IRQF_ONESHOT | IRQF_SHARED,
+				  dev_name(m->dev), m);
+	if (ret) {
+		dev_err(m->dev, "Unable to register interrupt handler!\n");
+		return ret;
+	}
+
+	mon_disable(m);
+
+	limit = mbps_to_bytes(mbps, hw->df->profile->polling_ms, 0);
+	mon_set_limit(m, limit);
+
+	mon_clear(m);
+	mon_irq_clear(m);
+	mon_irq_enable(m);
+	mon_enable(m);
+
+	return 0;
+}
+
+static void stop_bw_hwmon(struct bw_hwmon *hw)
+{
+	struct bwmon *m = to_bwmon(hw);
+
+	disable_irq(m->irq);
+	free_irq(m->irq, m);
+	mon_disable(m);
+	mon_irq_disable(m);
+	mon_clear(m);
+	mon_irq_clear(m);
+}
+
+/*************************************************************************/
+
+static int bimc_bwmon_driver_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct resource *res;
+	struct bwmon *m;
+	int ret;
+	u32 data;
+
+	m = devm_kzalloc(dev, sizeof(*m), GFP_KERNEL);
+	if (!m)
+		return -ENOMEM;
+	m->dev = dev;
+
+	ret = of_property_read_u32(dev->of_node, "qcom,mport", &data);
+	if (ret) {
+		dev_err(dev, "mport not found!\n");
+		return ret;
+	}
+	m->mport = data;
+
+	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "base");
+	if (!res) {
+		dev_err(dev, "base not found!\n");
+		return -EINVAL;
+	}
+	m->base = devm_ioremap(dev, res->start, resource_size(res));
+	if (!m->base) {
+		dev_err(dev, "Unable map base!\n");
+		return -ENOMEM;
+	}
+
+	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "global_base");
+	if (!res) {
+		dev_err(dev, "global_base not found!\n");
+		return -EINVAL;
+	}
+	m->global_base = devm_ioremap(dev, res->start, resource_size(res));
+	if (!m->global_base) {
+		dev_err(dev, "Unable map global_base!\n");
+		return -ENOMEM;
+	}
+
+	m->irq = platform_get_irq(pdev, 0);
+	if (m->irq < 0) {
+		dev_err(dev, "Unable to get IRQ number\n");
+		return m->irq;
+	}
+
+	m->hw.of_node = of_parse_phandle(dev->of_node, "qcom,target-dev", 0);
+	if (!m->hw.of_node)
+		return -EINVAL;
+	m->hw.start_hwmon = &start_bw_hwmon;
+	m->hw.stop_hwmon = &stop_bw_hwmon;
+	m->hw.meas_bw_and_set_irq = &meas_bw_and_set_irq;
+
+	ret = register_bw_hwmon(dev, &m->hw);
+	if (ret) {
+		dev_err(dev, "Dev BW hwmon registration failed\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+static const struct of_device_id bimc_bwmon_match_table[] = {
+	{ .compatible = "qcom,bimc-bwmon" },
+	{}
+};
+
+static struct platform_driver bimc_bwmon_driver = {
+	.probe = bimc_bwmon_driver_probe,
+	.driver = {
+		.name = "bimc-bwmon",
+		.of_match_table = bimc_bwmon_match_table,
+	},
+};
+
+module_platform_driver(bimc_bwmon_driver);
+MODULE_DESCRIPTION("BIMC bandwidth monitor driver");
+MODULE_LICENSE("GPL v2");