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SubjectRe: [RFC v2 1/1] drm/lima: Add optional devfreq support
On Sat, Dec 28, 2019 at 1:37 AM Martin Blumenstingl
<martin.blumenstingl@googlemail.com> wrote:
>
> Most platforms with a Mali-400 or Mali-450 GPU also have support for
> changing the GPU clock frequency. Add devfreq support so the GPU clock
> rate is updated based on the actual GPU usage when the
> "operating-points-v2" property is present in the board.dts.
>
> The actual devfreq code is taken from panfrost_devfreq.c and modified so
> it matches what the lima hardware needs:
> - a call to dev_pm_opp_set_clkname() during initialization because there
> are two clocks on Mali-4x0 IPs. "core" is the one that actually clocks
> the GPU so we need to control it using devfreq.
> - locking when reading or writing the devfreq statistics because (unlike
> than panfrost) we have multiple PP and GP IRQs which may finish jobs
> concurrently.
>
> Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
> ---
> drivers/gpu/drm/lima/Kconfig | 1 +
> drivers/gpu/drm/lima/Makefile | 3 +-
> drivers/gpu/drm/lima/lima_devfreq.c | 183 ++++++++++++++++++++++++++++
> drivers/gpu/drm/lima/lima_devfreq.h | 15 +++
> drivers/gpu/drm/lima/lima_device.c | 4 +
> drivers/gpu/drm/lima/lima_device.h | 17 +++
> drivers/gpu/drm/lima/lima_drv.c | 14 ++-
> drivers/gpu/drm/lima/lima_sched.c | 7 ++
> drivers/gpu/drm/lima/lima_sched.h | 3 +
> 9 files changed, 244 insertions(+), 3 deletions(-)
> create mode 100644 drivers/gpu/drm/lima/lima_devfreq.c
> create mode 100644 drivers/gpu/drm/lima/lima_devfreq.h
>
> diff --git a/drivers/gpu/drm/lima/Kconfig b/drivers/gpu/drm/lima/Kconfig
> index 571dc369a7e9..cdd24b68b5d4 100644
> --- a/drivers/gpu/drm/lima/Kconfig
> +++ b/drivers/gpu/drm/lima/Kconfig
> @@ -10,5 +10,6 @@ config DRM_LIMA
> depends on OF
> select DRM_SCHED
> select DRM_GEM_SHMEM_HELPER
> + select PM_DEVFREQ
> help
> DRM driver for ARM Mali 400/450 GPUs.
> diff --git a/drivers/gpu/drm/lima/Makefile b/drivers/gpu/drm/lima/Makefile
> index a85444b0a1d4..5e5c29875e9c 100644
> --- a/drivers/gpu/drm/lima/Makefile
> +++ b/drivers/gpu/drm/lima/Makefile
> @@ -14,6 +14,7 @@ lima-y := \
> lima_sched.o \
> lima_ctx.o \
> lima_dlbu.o \
> - lima_bcast.o
> + lima_bcast.o \
> + lima_devfreq.o
>
> obj-$(CONFIG_DRM_LIMA) += lima.o
> diff --git a/drivers/gpu/drm/lima/lima_devfreq.c b/drivers/gpu/drm/lima/lima_devfreq.c
> new file mode 100644
> index 000000000000..a5fd6b8faa77
> --- /dev/null
> +++ b/drivers/gpu/drm/lima/lima_devfreq.c
> @@ -0,0 +1,183 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright 2019 Martin Blumenstingl <martin.blumenstingl@googlemail.com>
> + *
> + * Based on panfrost_devfreq.c:
> + * Copyright 2019 Collabora ltd.
> + */
> +#include <linux/clk.h>
> +#include <linux/devfreq.h>
> +#include <linux/devfreq_cooling.h>
> +#include <linux/device.h>
> +#include <linux/platform_device.h>
> +#include <linux/pm_opp.h>
> +
> +#include "lima_device.h"
> +#include "lima_devfreq.h"
> +
> +static void lima_devfreq_update_utilization(struct lima_device *ldev)
> +{
> + unsigned long irqflags;
> + ktime_t now, last;
> +
> + if (!ldev->devfreq.devfreq)
> + return;
> +
> + spin_lock_irqsave(&ldev->devfreq.lock, irqflags);
> +
> + now = ktime_get();
> + last = ldev->devfreq.time_last_update;
> +
> + if (atomic_read(&ldev->devfreq.busy_count) > 0)
> + ldev->devfreq.busy_time += ktime_sub(now, last);
> + else
> + ldev->devfreq.idle_time += ktime_sub(now, last);
> +
> + ldev->devfreq.time_last_update = now;
> +
> + spin_unlock_irqrestore(&ldev->devfreq.lock, irqflags);
> +}
> +
> +static int lima_devfreq_target(struct device *dev, unsigned long *freq,
> + u32 flags)
> +{
> + struct dev_pm_opp *opp;
> + int err;
> +
> + opp = devfreq_recommended_opp(dev, freq, flags);
> + if (IS_ERR(opp))
> + return PTR_ERR(opp);
> + dev_pm_opp_put(opp);
> +
> + err = dev_pm_opp_set_rate(dev, *freq);
> + if (err)
> + return err;
> +
> + return 0;
> +}
> +
> +static void lima_devfreq_reset(struct lima_device *ldev)
> +{
> + unsigned long irqflags;
> +
> + spin_lock_irqsave(&ldev->devfreq.lock, irqflags);
> +
> + ldev->devfreq.busy_time = 0;
> + ldev->devfreq.idle_time = 0;
> + ldev->devfreq.time_last_update = ktime_get();
> +
> + spin_unlock_irqrestore(&ldev->devfreq.lock, irqflags);
> +}
> +
> +static int lima_devfreq_get_dev_status(struct device *dev,
> + struct devfreq_dev_status *status)
> +{
> + struct lima_device *ldev = dev_get_drvdata(dev);
> + unsigned long irqflags;
> +
> + lima_devfreq_update_utilization(ldev);
> +
> + status->current_frequency = clk_get_rate(ldev->clk_gpu);
> +
> + spin_lock_irqsave(&ldev->devfreq.lock, irqflags);
> +
> + status->total_time = ktime_to_ns(ktime_add(ldev->devfreq.busy_time,
> + ldev->devfreq.idle_time));
> + status->busy_time = ktime_to_ns(ldev->devfreq.busy_time);
> +
> + spin_unlock_irqrestore(&ldev->devfreq.lock, irqflags);
> +
> + lima_devfreq_reset(ldev);
> +
> + dev_dbg(ldev->dev, "busy %lu total %lu %lu %% freq %lu MHz\n",
> + status->busy_time, status->total_time,
> + status->busy_time / (status->total_time / 100),
> + status->current_frequency / 1000 / 1000);
> +
> + return 0;
> +}
> +
> +static struct devfreq_dev_profile lima_devfreq_profile = {
> + .polling_ms = 50, /* ~3 frames */
> + .target = lima_devfreq_target,
> + .get_dev_status = lima_devfreq_get_dev_status,
> +};
> +
> +int lima_devfreq_init(struct lima_device *ldev)
> +{
> + struct thermal_cooling_device *cooling;
> + struct device *dev = &ldev->pdev->dev;
> + struct devfreq *devfreq;
> + struct dev_pm_opp *opp;
> + unsigned long cur_freq;
> + int ret;
> +
> + spin_lock_init(&ldev->devfreq.lock);
> +
> + ldev->devfreq.opp_table = dev_pm_opp_set_clkname(dev, "core");
> + if (IS_ERR(ldev->devfreq.opp_table))
> + return PTR_ERR(ldev->devfreq.opp_table);
> +
> + ret = dev_pm_opp_of_add_table(dev);
> + if (ret == -ENODEV) /* Optional, continue without devfreq */
> + return 0;
> + else if (ret)
> + return ret;
> +
> + lima_devfreq_reset(ldev);
> +
> + cur_freq = clk_get_rate(ldev->clk_gpu);
> +
> + opp = devfreq_recommended_opp(dev, &cur_freq, 0);
> + if (IS_ERR(opp))
> + return PTR_ERR(opp);
> +
> + lima_devfreq_profile.initial_freq = cur_freq;
> + dev_pm_opp_put(opp);
> +
> + devfreq = devm_devfreq_add_device(dev, &lima_devfreq_profile,
> + DEVFREQ_GOV_SIMPLE_ONDEMAND, NULL);
> + if (IS_ERR(devfreq)) {
> + dev_err(dev, "Couldn't initialize GPU devfreq\n");
> + dev_pm_opp_of_remove_table(dev);
> + return PTR_ERR(devfreq);
> + }
> +
> + ldev->devfreq.devfreq = devfreq;
> +
> + cooling = of_devfreq_cooling_register(dev->of_node, devfreq);
> + if (IS_ERR(cooling))
> + dev_info(dev, "Failed to register cooling device\n");
> + else
> + ldev->devfreq.cooling = cooling;
> +
> + return 0;
> +}
> +
> +void lima_devfreq_fini(struct lima_device *ldev)
> +{
> + if (ldev->devfreq.cooling)
> + devfreq_cooling_unregister(ldev->devfreq.cooling);
> +
> + if (ldev->devfreq.opp_table) {
> + dev_pm_opp_put_clkname(ldev->devfreq.opp_table);
> + ldev->devfreq.opp_table = NULL;
> + }
> +
> + dev_pm_opp_of_remove_table(&ldev->pdev->dev);
> +}
> +
> +void lima_devfreq_record_busy(struct lima_device *ldev)
> +{
> + lima_devfreq_update_utilization(ldev);
> + atomic_inc(&ldev->devfreq.busy_count);
> +}
> +
> +void lima_devfreq_record_idle(struct lima_device *ldev)
> +{
> + int count;
> +
> + lima_devfreq_update_utilization(ldev);
> + count = atomic_dec_if_positive(&ldev->devfreq.busy_count);
> + WARN_ON(count < 0);
> +}
> diff --git a/drivers/gpu/drm/lima/lima_devfreq.h b/drivers/gpu/drm/lima/lima_devfreq.h
> new file mode 100644
> index 000000000000..fe4f8a437033
> --- /dev/null
> +++ b/drivers/gpu/drm/lima/lima_devfreq.h
> @@ -0,0 +1,15 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/* Copyright 2019 Martin Blumenstingl <martin.blumenstingl@googlemail.com> */
> +
> +#ifndef __LIMA_DEVFREQ_H__
> +#define __LIMA_DEVFREQ_H__
> +
> +struct lima_device;
> +
> +int lima_devfreq_init(struct lima_device *ldev);
> +void lima_devfreq_fini(struct lima_device *ldev);
> +
> +void lima_devfreq_record_busy(struct lima_device *ldev);
> +void lima_devfreq_record_idle(struct lima_device *ldev);
> +
> +#endif
> diff --git a/drivers/gpu/drm/lima/lima_device.c b/drivers/gpu/drm/lima/lima_device.c
> index 19829b543024..7f1f7a1c03e5 100644
> --- a/drivers/gpu/drm/lima/lima_device.c
> +++ b/drivers/gpu/drm/lima/lima_device.c
> @@ -214,6 +214,8 @@ static int lima_init_gp_pipe(struct lima_device *dev)
> struct lima_sched_pipe *pipe = dev->pipe + lima_pipe_gp;
> int err;
>
> + pipe->ldev = dev;
> +
> err = lima_sched_pipe_init(pipe, "gp");
> if (err)
> return err;
> @@ -244,6 +246,8 @@ static int lima_init_pp_pipe(struct lima_device *dev)
> struct lima_sched_pipe *pipe = dev->pipe + lima_pipe_pp;
> int err, i;
>
> + pipe->ldev = dev;
> +
> err = lima_sched_pipe_init(pipe, "pp");
> if (err)
> return err;
> diff --git a/drivers/gpu/drm/lima/lima_device.h b/drivers/gpu/drm/lima/lima_device.h
> index 31158d86271c..26f0efdd17f1 100644
> --- a/drivers/gpu/drm/lima/lima_device.h
> +++ b/drivers/gpu/drm/lima/lima_device.h
> @@ -5,6 +5,7 @@
> #define __LIMA_DEVICE_H__
>
> #include <drm/drm_device.h>
> +#include <linux/atomic.h>
> #include <linux/delay.h>
>
> #include "lima_sched.h"
> @@ -94,6 +95,22 @@ struct lima_device {
>
> u32 *dlbu_cpu;
> dma_addr_t dlbu_dma;
> +
> + struct {
> + struct devfreq *devfreq;
> + struct opp_table *opp_table;
> + struct thermal_cooling_device *cooling;
> + ktime_t busy_time;
> + ktime_t idle_time;
> + ktime_t time_last_update;
> + atomic_t busy_count;
> + /*
> + * Protect busy_time, idle_time and time_last_update because
> + * these can be updated concurrently - for example by the GP
> + * and PP interrupts.
> + */
> + spinlock_t lock;
> + } devfreq;
> };
>
> static inline struct lima_device *
> diff --git a/drivers/gpu/drm/lima/lima_drv.c b/drivers/gpu/drm/lima/lima_drv.c
> index 124efe4fa97b..b64b1777f220 100644
> --- a/drivers/gpu/drm/lima/lima_drv.c
> +++ b/drivers/gpu/drm/lima/lima_drv.c
> @@ -10,6 +10,7 @@
> #include <drm/drm_prime.h>
> #include <drm/lima_drm.h>
>
> +#include "lima_devfreq.h"
> #include "lima_drv.h"
> #include "lima_gem.h"
> #include "lima_vm.h"
> @@ -296,18 +297,26 @@ static int lima_pdev_probe(struct platform_device *pdev)
> if (err)
> goto err_out1;
>
> + err = lima_devfreq_init(ldev);
> + if (err) {
> + dev_err(&pdev->dev, "Fatal error during devfreq init\n");
> + goto err_out2;
> + }
> +
> /*
> * Register the DRM device with the core and the connectors with
> * sysfs.
> */
> err = drm_dev_register(ddev, 0);
> if (err < 0)
> - goto err_out2;
> + goto err_out3;
>
> return 0;
>
> -err_out2:
> +err_out3:
> lima_device_fini(ldev);
> +err_out2:
> + lima_devfreq_fini(ldev);
> err_out1:
> drm_dev_put(ddev);
> err_out0:
> @@ -321,6 +330,7 @@ static int lima_pdev_remove(struct platform_device *pdev)
> struct drm_device *ddev = ldev->ddev;
>
> drm_dev_unregister(ddev);
> + lima_devfreq_fini(ldev);
> lima_device_fini(ldev);
> drm_dev_put(ddev);
> lima_sched_slab_fini();
> diff --git a/drivers/gpu/drm/lima/lima_sched.c b/drivers/gpu/drm/lima/lima_sched.c
> index f522c5f99729..851c496a168b 100644
> --- a/drivers/gpu/drm/lima/lima_sched.c
> +++ b/drivers/gpu/drm/lima/lima_sched.c
> @@ -5,6 +5,7 @@
> #include <linux/slab.h>
> #include <linux/xarray.h>
>
> +#include "lima_devfreq.h"
> #include "lima_drv.h"
> #include "lima_sched.h"
> #include "lima_vm.h"
> @@ -213,6 +214,8 @@ static struct dma_fence *lima_sched_run_job(struct drm_sched_job *job)
> */
> ret = dma_fence_get(task->fence);
>
> + lima_devfreq_record_busy(pipe->ldev);
> +
> pipe->current_task = task;
>
> /* this is needed for MMU to work correctly, otherwise GP/PP
> @@ -280,6 +283,8 @@ static void lima_sched_handle_error_task(struct lima_sched_pipe *pipe,
> pipe->current_vm = NULL;
> pipe->current_task = NULL;
>
> + lima_devfreq_record_idle(pipe->ldev);
> +
> drm_sched_resubmit_jobs(&pipe->base);
> drm_sched_start(&pipe->base, true);
> }
> @@ -348,6 +353,8 @@ void lima_sched_pipe_fini(struct lima_sched_pipe *pipe)
>
> void lima_sched_pipe_task_done(struct lima_sched_pipe *pipe)
> {
> + lima_devfreq_record_idle(pipe->ldev);

This should be moved to the else {} part of the following code. As you
have added the save
idle record to the lima_sched_handle_error_task which is just the if
{} part of the following
code, so no need to call it twice for error tasks. BTW.
lima_sched_handle_error_task is also
used for timeout tasks, so add idle record in it is fine.

Regards,
Qiang

> +
> if (pipe->error)
> schedule_work(&pipe->error_work);
> else {
> diff --git a/drivers/gpu/drm/lima/lima_sched.h b/drivers/gpu/drm/lima/lima_sched.h
> index 928af91c1118..9ae7df7d7fbb 100644
> --- a/drivers/gpu/drm/lima/lima_sched.h
> +++ b/drivers/gpu/drm/lima/lima_sched.h
> @@ -6,6 +6,7 @@
>
> #include <drm/gpu_scheduler.h>
>
> +struct lima_device;
> struct lima_vm;
>
> struct lima_sched_task {
> @@ -41,6 +42,8 @@ struct lima_sched_pipe {
> u32 fence_seqno;
> spinlock_t fence_lock;
>
> + struct lima_device *ldev;
> +
> struct lima_sched_task *current_task;
> struct lima_vm *current_vm;
>
> --
> 2.24.1
>

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