[PATCH v2 3/5] perf: stm32: ddrperfm driver creation

From: Gerald BAEZA
Date: Mon May 20 2019 - 11:30:40 EST


The DDRPERFM is the DDR Performance Monitor embedded in STM32MP1 SOC.

This perf drivers supports the read, write, activate, idle and total
time counters, described in the reference manual RM0436.

A 'bandwidth' attribute is added in the 'ddrperfm' event_source in order
to directly get the read and write bandwidths (in MB/s), from the last
read, write and total time counters reading.
This attribute is aside the 'events' attributes group because it is not
a counter, as seen by perf tool.

Signed-off-by: Gerald Baeza <gerald.baeza@xxxxxx>
---
drivers/perf/Kconfig | 6 +
drivers/perf/Makefile | 1 +
drivers/perf/stm32_ddr_pmu.c | 512 +++++++++++++++++++++++++++++++++++++++++++
3 files changed, 519 insertions(+)
create mode 100644 drivers/perf/stm32_ddr_pmu.c

diff --git a/drivers/perf/Kconfig b/drivers/perf/Kconfig
index a94e586..9add8a7 100644
--- a/drivers/perf/Kconfig
+++ b/drivers/perf/Kconfig
@@ -105,6 +105,12 @@ config THUNDERX2_PMU
The SoC has PMU support in its L3 cache controller (L3C) and
in the DDR4 Memory Controller (DMC).

+config STM32_DDR_PMU
+ tristate "STM32 DDR PMU"
+ depends on MACH_STM32MP157
+ help
+ Support for STM32 DDR performance monitor (DDRPERFM).
+
config XGENE_PMU
depends on ARCH_XGENE
bool "APM X-Gene SoC PMU"
diff --git a/drivers/perf/Makefile b/drivers/perf/Makefile
index 3048994..fa64719 100644
--- a/drivers/perf/Makefile
+++ b/drivers/perf/Makefile
@@ -8,6 +8,7 @@ obj-$(CONFIG_ARM_SMMU_V3_PMU) += arm_smmuv3_pmu.o
obj-$(CONFIG_HISI_PMU) += hisilicon/
obj-$(CONFIG_QCOM_L2_PMU) += qcom_l2_pmu.o
obj-$(CONFIG_QCOM_L3_PMU) += qcom_l3_pmu.o
+obj-$(CONFIG_STM32_DDR_PMU) += stm32_ddr_pmu.o
obj-$(CONFIG_THUNDERX2_PMU) += thunderx2_pmu.o
obj-$(CONFIG_XGENE_PMU) += xgene_pmu.o
obj-$(CONFIG_ARM_SPE_PMU) += arm_spe_pmu.o
diff --git a/drivers/perf/stm32_ddr_pmu.c b/drivers/perf/stm32_ddr_pmu.c
new file mode 100644
index 0000000..ae4a813
--- /dev/null
+++ b/drivers/perf/stm32_ddr_pmu.c
@@ -0,0 +1,512 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * This file is the STM32 DDR performance monitor (DDRPERFM) driver
+ *
+ * Copyright (C) 2019, STMicroelectronics - All Rights Reserved
+ * Author: Gerald Baeza <gerald.baeza@xxxxxx>
+ */
+
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/hrtimer.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of_platform.h>
+#include <linux/perf_event.h>
+#include <linux/reset.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+
+#define POLL_MS 4000 /* The counter roll over after ~8s @533MHz */
+#define WORD_LENGTH 4 /* Bytes */
+#define BURST_LENGTH 8 /* Words */
+
+#define DDRPERFM_CTL 0x000
+#define DDRPERFM_CFG 0x004
+#define DDRPERFM_STATUS 0x008
+#define DDRPERFM_CCR 0x00C
+#define DDRPERFM_IER 0x010
+#define DDRPERFM_ISR 0x014
+#define DDRPERFM_ICR 0x018
+#define DDRPERFM_TCNT 0x020
+#define DDRPERFM_CNT(X) (0x030 + 8 * (X))
+#define DDRPERFM_HWCFG 0x3F0
+#define DDRPERFM_VER 0x3F4
+#define DDRPERFM_ID 0x3F8
+#define DDRPERFM_SID 0x3FC
+
+#define CTL_START 0x00000001
+#define CTL_STOP 0x00000002
+#define CCR_CLEAR_ALL 0x8000000F
+#define SID_MAGIC_ID 0xA3C5DD01
+
+#define STRING "Read = %llu, Write = %llu, Read & Write = %llu (MB/s)\n"
+
+enum {
+ READ_CNT,
+ WRITE_CNT,
+ ACTIVATE_CNT,
+ IDLE_CNT,
+ TIME_CNT,
+ PMU_NR_COUNTERS
+};
+
+struct stm32_ddr_pmu {
+ struct pmu pmu;
+ void __iomem *membase;
+ struct clk *clk;
+ struct clk *clk_ddr;
+ unsigned long clk_ddr_rate;
+ struct hrtimer hrtimer;
+ ktime_t poll_period;
+ spinlock_t lock; /* for shared registers access */
+ struct perf_event *events[PMU_NR_COUNTERS];
+ u64 events_cnt[PMU_NR_COUNTERS];
+};
+
+static inline struct stm32_ddr_pmu *pmu_to_stm32_ddr_pmu(struct pmu *p)
+{
+ return container_of(p, struct stm32_ddr_pmu, pmu);
+}
+
+static inline struct stm32_ddr_pmu *hrtimer_to_stm32_ddr_pmu(struct hrtimer *h)
+{
+ return container_of(h, struct stm32_ddr_pmu, hrtimer);
+}
+
+static u64 stm32_ddr_pmu_compute_bw(struct stm32_ddr_pmu *stm32_ddr_pmu,
+ int counter)
+{
+ u64 bw = stm32_ddr_pmu->events_cnt[counter], tmp;
+ u64 div = stm32_ddr_pmu->events_cnt[TIME_CNT];
+ u32 prediv = 1, premul = 1;
+
+ if (bw && div) {
+ /* Maximize the dividend into 64 bits */
+ while ((bw < 0x8000000000000000ULL) &&
+ (premul < 0x40000000UL)) {
+ bw = bw << 1;
+ premul *= 2;
+ }
+ /* Minimize the dividor to fit in 32 bits */
+ while ((div > 0xffffffffUL) && (prediv < 0x40000000UL)) {
+ div = div >> 1;
+ prediv *= 2;
+ }
+ /* Divide counter per time and multiply per DDR settings */
+ do_div(bw, div);
+ tmp = bw * BURST_LENGTH * WORD_LENGTH;
+ tmp *= stm32_ddr_pmu->clk_ddr_rate;
+ if (tmp < bw)
+ goto error;
+ bw = tmp;
+ /* Cancel the prediv and premul factors */
+ while (prediv > 1) {
+ bw = bw >> 1;
+ prediv /= 2;
+ }
+ while (premul > 1) {
+ bw = bw >> 1;
+ premul /= 2;
+ }
+ /* Convert MHz to Hz and B to MB, to finally get MB/s */
+ tmp = bw * 1000000;
+ if (tmp < bw)
+ goto error;
+ bw = tmp;
+ premul = 1024 * 1024;
+ while (premul > 1) {
+ bw = bw >> 1;
+ premul /= 2;
+ }
+ }
+ return bw;
+
+error:
+ pr_warn("stm32-ddr-pmu: overflow detected\n");
+ return 0;
+}
+
+static void stm32_ddr_pmu_event_configure(struct perf_event *event)
+{
+ struct stm32_ddr_pmu *stm32_ddr_pmu = pmu_to_stm32_ddr_pmu(event->pmu);
+ unsigned long lock_flags, config_base = event->hw.config_base;
+ u32 val;
+
+ spin_lock_irqsave(&stm32_ddr_pmu->lock, lock_flags);
+ writel_relaxed(CTL_STOP, stm32_ddr_pmu->membase + DDRPERFM_CTL);
+
+ if (config_base < TIME_CNT) {
+ val = readl_relaxed(stm32_ddr_pmu->membase + DDRPERFM_CFG);
+ val |= (1 << config_base);
+ writel_relaxed(val, stm32_ddr_pmu->membase + DDRPERFM_CFG);
+ }
+ spin_unlock_irqrestore(&stm32_ddr_pmu->lock, lock_flags);
+}
+
+static void stm32_ddr_pmu_event_read(struct perf_event *event)
+{
+ struct stm32_ddr_pmu *stm32_ddr_pmu = pmu_to_stm32_ddr_pmu(event->pmu);
+ unsigned long flags, config_base = event->hw.config_base;
+ struct hw_perf_event *hw = &event->hw;
+ u64 prev_count, new_count, mask;
+ u32 val, offset, bit;
+
+ spin_lock_irqsave(&stm32_ddr_pmu->lock, flags);
+
+ writel_relaxed(CTL_STOP, stm32_ddr_pmu->membase + DDRPERFM_CTL);
+
+ if (config_base == TIME_CNT) {
+ offset = DDRPERFM_TCNT;
+ bit = 1 << 31;
+ } else {
+ offset = DDRPERFM_CNT(config_base);
+ bit = 1 << config_base;
+ }
+ val = readl_relaxed(stm32_ddr_pmu->membase + DDRPERFM_STATUS);
+ if (val & bit)
+ pr_warn("stm32_ddr_pmu hardware overflow\n");
+ val = readl_relaxed(stm32_ddr_pmu->membase + offset);
+ writel_relaxed(bit, stm32_ddr_pmu->membase + DDRPERFM_CCR);
+ writel_relaxed(CTL_START, stm32_ddr_pmu->membase + DDRPERFM_CTL);
+
+ do {
+ prev_count = local64_read(&hw->prev_count);
+ new_count = prev_count + val;
+ } while (local64_xchg(&hw->prev_count, new_count) != prev_count);
+
+ mask = GENMASK_ULL(31, 0);
+ local64_add(val & mask, &event->count);
+
+ if (new_count < prev_count)
+ pr_warn("STM32 DDR PMU counter saturated\n");
+
+ spin_unlock_irqrestore(&stm32_ddr_pmu->lock, flags);
+}
+
+static void stm32_ddr_pmu_event_start(struct perf_event *event, int flags)
+{
+ struct stm32_ddr_pmu *stm32_ddr_pmu = pmu_to_stm32_ddr_pmu(event->pmu);
+ struct hw_perf_event *hw = &event->hw;
+ unsigned long lock_flags;
+
+ if (WARN_ON_ONCE(!(hw->state & PERF_HES_STOPPED)))
+ return;
+
+ if (flags & PERF_EF_RELOAD)
+ WARN_ON_ONCE(!(hw->state & PERF_HES_UPTODATE));
+
+ stm32_ddr_pmu_event_configure(event);
+
+ /* Clear all counters to synchronize them, then start */
+ spin_lock_irqsave(&stm32_ddr_pmu->lock, lock_flags);
+ writel_relaxed(CCR_CLEAR_ALL, stm32_ddr_pmu->membase + DDRPERFM_CCR);
+ writel_relaxed(CTL_START, stm32_ddr_pmu->membase + DDRPERFM_CTL);
+ spin_unlock_irqrestore(&stm32_ddr_pmu->lock, lock_flags);
+
+ hw->state = 0;
+}
+
+static void stm32_ddr_pmu_event_stop(struct perf_event *event, int flags)
+{
+ struct stm32_ddr_pmu *stm32_ddr_pmu = pmu_to_stm32_ddr_pmu(event->pmu);
+ unsigned long lock_flags, config_base = event->hw.config_base;
+ struct hw_perf_event *hw = &event->hw;
+ u32 val, bit;
+
+ if (WARN_ON_ONCE(hw->state & PERF_HES_STOPPED))
+ return;
+
+ spin_lock_irqsave(&stm32_ddr_pmu->lock, lock_flags);
+ writel_relaxed(CTL_STOP, stm32_ddr_pmu->membase + DDRPERFM_CTL);
+ if (config_base == TIME_CNT)
+ bit = 1 << 31;
+ else
+ bit = 1 << config_base;
+ writel_relaxed(bit, stm32_ddr_pmu->membase + DDRPERFM_CCR);
+ if (config_base < TIME_CNT) {
+ val = readl_relaxed(stm32_ddr_pmu->membase + DDRPERFM_CFG);
+ val &= ~bit;
+ writel_relaxed(val, stm32_ddr_pmu->membase + DDRPERFM_CFG);
+ }
+ spin_unlock_irqrestore(&stm32_ddr_pmu->lock, lock_flags);
+
+ hw->state |= PERF_HES_STOPPED;
+
+ if (flags & PERF_EF_UPDATE) {
+ stm32_ddr_pmu_event_read(event);
+ hw->state |= PERF_HES_UPTODATE;
+ }
+}
+
+static int stm32_ddr_pmu_event_add(struct perf_event *event, int flags)
+{
+ struct stm32_ddr_pmu *stm32_ddr_pmu = pmu_to_stm32_ddr_pmu(event->pmu);
+ unsigned long config_base = event->hw.config_base;
+ struct hw_perf_event *hw = &event->hw;
+
+ stm32_ddr_pmu->events_cnt[config_base] = 0;
+ stm32_ddr_pmu->events[config_base] = event;
+
+ clk_enable(stm32_ddr_pmu->clk);
+ hrtimer_start(&stm32_ddr_pmu->hrtimer, stm32_ddr_pmu->poll_period,
+ HRTIMER_MODE_REL);
+
+ stm32_ddr_pmu_event_configure(event);
+
+ hw->state = PERF_HES_STOPPED | PERF_HES_UPTODATE;
+
+ if (flags & PERF_EF_START)
+ stm32_ddr_pmu_event_start(event, 0);
+
+ return 0;
+}
+
+static void stm32_ddr_pmu_event_del(struct perf_event *event, int flags)
+{
+ struct stm32_ddr_pmu *stm32_ddr_pmu = pmu_to_stm32_ddr_pmu(event->pmu);
+ unsigned long config_base = event->hw.config_base;
+ bool stop = true;
+ int i;
+
+ stm32_ddr_pmu_event_stop(event, PERF_EF_UPDATE);
+
+ stm32_ddr_pmu->events_cnt[config_base] += local64_read(&event->count);
+ stm32_ddr_pmu->events[config_base] = NULL;
+
+ for (i = 0; i < PMU_NR_COUNTERS; i++)
+ if (stm32_ddr_pmu->events[i])
+ stop = false;
+ if (stop)
+ hrtimer_cancel(&stm32_ddr_pmu->hrtimer);
+
+ clk_disable(stm32_ddr_pmu->clk);
+}
+
+static int stm32_ddr_pmu_event_init(struct perf_event *event)
+{
+ struct hw_perf_event *hw = &event->hw;
+
+ if (is_sampling_event(event))
+ return -EINVAL;
+
+ if (event->attach_state & PERF_ATTACH_TASK)
+ return -EINVAL;
+
+ if (event->attr.exclude_user ||
+ event->attr.exclude_kernel ||
+ event->attr.exclude_hv ||
+ event->attr.exclude_idle ||
+ event->attr.exclude_host ||
+ event->attr.exclude_guest)
+ return -EINVAL;
+
+ if (event->cpu < 0)
+ return -EINVAL;
+
+ hw->config_base = event->attr.config;
+
+ return 0;
+}
+
+static enum hrtimer_restart stm32_ddr_pmu_poll(struct hrtimer *hrtimer)
+{
+ struct stm32_ddr_pmu *stm32_ddr_pmu = hrtimer_to_stm32_ddr_pmu(hrtimer);
+ int i;
+
+ for (i = 0; i < PMU_NR_COUNTERS; i++)
+ if (stm32_ddr_pmu->events[i])
+ stm32_ddr_pmu_event_read(stm32_ddr_pmu->events[i]);
+
+ hrtimer_forward_now(hrtimer, stm32_ddr_pmu->poll_period);
+
+ return HRTIMER_RESTART;
+}
+
+static ssize_t stm32_ddr_pmu_sysfs_show(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct dev_ext_attribute *eattr;
+
+ eattr = container_of(attr, struct dev_ext_attribute, attr);
+
+ return sprintf(buf, "config=0x%lx\n", (unsigned long)eattr->var);
+}
+
+static ssize_t bandwidth_show(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct stm32_ddr_pmu *stm32_ddr_pmu = dev_get_drvdata(dev);
+ u64 r_bw, w_bw;
+ int ret;
+
+ if (stm32_ddr_pmu->events_cnt[TIME_CNT]) {
+ r_bw = stm32_ddr_pmu_compute_bw(stm32_ddr_pmu, READ_CNT);
+ w_bw = stm32_ddr_pmu_compute_bw(stm32_ddr_pmu, WRITE_CNT);
+
+ ret = snprintf(buf, PAGE_SIZE, STRING,
+ r_bw, w_bw, (r_bw + w_bw));
+ } else {
+ ret = snprintf(buf, PAGE_SIZE, "No data available\n");
+ }
+
+ return ret;
+}
+
+#define STM32_DDR_PMU_ATTR(_name, _func, _config) \
+ (&((struct dev_ext_attribute[]) { \
+ { __ATTR(_name, 0444, _func, NULL), (void *)_config } \
+ })[0].attr.attr)
+
+#define STM32_DDR_PMU_EVENT_ATTR(_name, _config) \
+ STM32_DDR_PMU_ATTR(_name, stm32_ddr_pmu_sysfs_show, \
+ (unsigned long)_config)
+
+static struct attribute *stm32_ddr_pmu_event_attrs[] = {
+ STM32_DDR_PMU_EVENT_ATTR(read_cnt, READ_CNT),
+ STM32_DDR_PMU_EVENT_ATTR(write_cnt, WRITE_CNT),
+ STM32_DDR_PMU_EVENT_ATTR(activate_cnt, ACTIVATE_CNT),
+ STM32_DDR_PMU_EVENT_ATTR(idle_cnt, IDLE_CNT),
+ STM32_DDR_PMU_EVENT_ATTR(time_cnt, TIME_CNT),
+ NULL
+};
+
+static DEVICE_ATTR_RO(bandwidth);
+static struct attribute *stm32_ddr_pmu_bandwidth_attrs[] = {
+ &dev_attr_bandwidth.attr,
+ NULL,
+};
+
+static struct attribute_group stm32_ddr_pmu_event_attrs_group = {
+ .name = "events",
+ .attrs = stm32_ddr_pmu_event_attrs,
+};
+
+static struct attribute_group stm32_ddr_pmu_bandwidth_attrs_group = {
+ .attrs = stm32_ddr_pmu_bandwidth_attrs,
+};
+
+static const struct attribute_group *stm32_ddr_pmu_attr_groups[] = {
+ &stm32_ddr_pmu_event_attrs_group,
+ &stm32_ddr_pmu_bandwidth_attrs_group,
+ NULL,
+};
+
+static int stm32_ddr_pmu_device_probe(struct platform_device *pdev)
+{
+ struct stm32_ddr_pmu *stm32_ddr_pmu;
+ struct reset_control *rst;
+ struct resource *res;
+ int i, ret;
+ u32 val;
+
+ stm32_ddr_pmu = devm_kzalloc(&pdev->dev, sizeof(struct stm32_ddr_pmu),
+ GFP_KERNEL);
+ if (!stm32_ddr_pmu)
+ return -ENOMEM;
+ platform_set_drvdata(pdev, stm32_ddr_pmu);
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ stm32_ddr_pmu->membase = devm_ioremap_resource(&pdev->dev, res);
+ if (IS_ERR(stm32_ddr_pmu->membase)) {
+ pr_warn("Unable to get STM32 DDR PMU membase\n");
+ return PTR_ERR(stm32_ddr_pmu->membase);
+ }
+
+ stm32_ddr_pmu->clk = devm_clk_get(&pdev->dev, "bus");
+ if (IS_ERR(stm32_ddr_pmu->clk)) {
+ pr_warn("Unable to get STM32 DDR PMU clock\n");
+ return PTR_ERR(stm32_ddr_pmu->clk);
+ }
+
+ ret = clk_prepare_enable(stm32_ddr_pmu->clk);
+ if (ret) {
+ pr_warn("Unable to prepare STM32 DDR PMU clock\n");
+ return ret;
+ }
+
+ stm32_ddr_pmu->clk_ddr = devm_clk_get(&pdev->dev, "ddr");
+ if (IS_ERR(stm32_ddr_pmu->clk_ddr)) {
+ pr_warn("Unable to get STM32 DDR clock\n");
+ return PTR_ERR(stm32_ddr_pmu->clk_ddr);
+ }
+ stm32_ddr_pmu->clk_ddr_rate = clk_get_rate(stm32_ddr_pmu->clk_ddr);
+ stm32_ddr_pmu->clk_ddr_rate /= 1000000;
+
+ stm32_ddr_pmu->poll_period = ms_to_ktime(POLL_MS);
+ hrtimer_init(&stm32_ddr_pmu->hrtimer, CLOCK_MONOTONIC,
+ HRTIMER_MODE_REL);
+ stm32_ddr_pmu->hrtimer.function = stm32_ddr_pmu_poll;
+ spin_lock_init(&stm32_ddr_pmu->lock);
+
+ for (i = 0; i < PMU_NR_COUNTERS; i++) {
+ stm32_ddr_pmu->events[i] = NULL;
+ stm32_ddr_pmu->events_cnt[i] = 0;
+ }
+
+ val = readl_relaxed(stm32_ddr_pmu->membase + DDRPERFM_SID);
+ if (val != SID_MAGIC_ID)
+ return -EINVAL;
+
+ stm32_ddr_pmu->pmu = (struct pmu) {
+ .task_ctx_nr = perf_invalid_context,
+ .start = stm32_ddr_pmu_event_start,
+ .stop = stm32_ddr_pmu_event_stop,
+ .add = stm32_ddr_pmu_event_add,
+ .del = stm32_ddr_pmu_event_del,
+ .event_init = stm32_ddr_pmu_event_init,
+ .attr_groups = stm32_ddr_pmu_attr_groups,
+ };
+ ret = perf_pmu_register(&stm32_ddr_pmu->pmu, "ddrperfm", -1);
+ if (ret) {
+ pr_warn("Unable to register STM32 DDR PMU\n");
+ return ret;
+ }
+
+ rst = devm_reset_control_get_exclusive(&pdev->dev, NULL);
+ if (!IS_ERR(rst)) {
+ reset_control_assert(rst);
+ udelay(2);
+ reset_control_deassert(rst);
+ }
+
+ pr_info("stm32-ddr-pmu: probed (ID=0x%08x VER=0x%08x), DDR@%luMHz\n",
+ readl_relaxed(stm32_ddr_pmu->membase + DDRPERFM_ID),
+ readl_relaxed(stm32_ddr_pmu->membase + DDRPERFM_VER),
+ stm32_ddr_pmu->clk_ddr_rate);
+
+ clk_disable(stm32_ddr_pmu->clk);
+
+ return 0;
+}
+
+static int stm32_ddr_pmu_device_remove(struct platform_device *pdev)
+{
+ struct stm32_ddr_pmu *stm32_ddr_pmu = platform_get_drvdata(pdev);
+
+ perf_pmu_unregister(&stm32_ddr_pmu->pmu);
+
+ return 0;
+}
+
+static const struct of_device_id stm32_ddr_pmu_of_match[] = {
+ { .compatible = "st,stm32-ddr-pmu" },
+ { },
+};
+
+static struct platform_driver stm32_ddr_pmu_driver = {
+ .driver = {
+ .name = "stm32-ddr-pmu",
+ .of_match_table = of_match_ptr(stm32_ddr_pmu_of_match),
+ },
+ .probe = stm32_ddr_pmu_device_probe,
+ .remove = stm32_ddr_pmu_device_remove,
+};
+
+module_platform_driver(stm32_ddr_pmu_driver);
+
+MODULE_DESCRIPTION("Perf driver for STM32 DDR performance monitor");
+MODULE_AUTHOR("Gerald Baeza <gerald.baeza@xxxxxx>");
+MODULE_LICENSE("GPL v2");
--
2.7.4