[1/3] gpu: host1x: Add support for DMA fences

From: Mikko Perttunen <mperttunen@nvidia.com>

Add an implementation of DMA fences backed by Host1x syncpoints,
an interface to specify a prefence for job submissions.

Before submission, prefences containing only Host1x syncpoints
are waited by pushing wait commands to CDMA, whereas other
fences are CPU-waited.

Signed-off-by: Mikko Perttunen <mperttunen@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
---
 drivers/gpu/host1x/Kconfig         |   1 +
 drivers/gpu/host1x/Makefile        |   1 +
 drivers/gpu/host1x/dev.h           |  12 ++-
 drivers/gpu/host1x/fence.c         | 202 +++++++++++++++++++++++++++++++++++++
 drivers/gpu/host1x/fence.h         |  28 +++++
 drivers/gpu/host1x/hw/channel_hw.c |  36 +++++--
 drivers/gpu/host1x/intr.c          |  11 +-
 drivers/gpu/host1x/intr.h          |   8 +-
 drivers/gpu/host1x/syncpt.c        |   2 +
 include/linux/host1x.h             |  12 ++-
 10 files changed, 302 insertions(+), 11 deletions(-)
 create mode 100644 drivers/gpu/host1x/fence.c
 create mode 100644 drivers/gpu/host1x/fence.h

On 12.01.2018 01:22, Thierry Reding wrote:
> From: Mikko Perttunen <mperttunen@nvidia.com>
> 
> Add an implementation of DMA fences backed by Host1x syncpoints,
> an interface to specify a prefence for job submissions.
> 
> Before submission, prefences containing only Host1x syncpoints
> are waited by pushing wait commands to CDMA, whereas other
> fences are CPU-waited.
> 
> Signed-off-by: Mikko Perttunen <mperttunen@nvidia.com>
> Signed-off-by: Thierry Reding <treding@nvidia.com>
> ---
>  drivers/gpu/host1x/Kconfig         |   1 +
>  drivers/gpu/host1x/Makefile        |   1 +
>  drivers/gpu/host1x/dev.h           |  12 ++-
>  drivers/gpu/host1x/fence.c         | 202 +++++++++++++++++++++++++++++++++++++
>  drivers/gpu/host1x/fence.h         |  28 +++++
>  drivers/gpu/host1x/hw/channel_hw.c |  36 +++++--
>  drivers/gpu/host1x/intr.c          |  11 +-
>  drivers/gpu/host1x/intr.h          |   8 +-
>  drivers/gpu/host1x/syncpt.c        |   2 +
>  include/linux/host1x.h             |  12 ++-
>  10 files changed, 302 insertions(+), 11 deletions(-)
>  create mode 100644 drivers/gpu/host1x/fence.c
>  create mode 100644 drivers/gpu/host1x/fence.h
> 
> diff --git a/drivers/gpu/host1x/Kconfig b/drivers/gpu/host1x/Kconfig
> index 91916326957f..e41032ebf16d 100644
> --- a/drivers/gpu/host1x/Kconfig
> +++ b/drivers/gpu/host1x/Kconfig
> @@ -1,6 +1,7 @@
>  config TEGRA_HOST1X
>  	tristate "NVIDIA Tegra host1x driver"
>  	depends on ARCH_TEGRA || (ARM && COMPILE_TEST)
> +	select DMA_SHARED_BUFFER
>  	select IOMMU_IOVA if IOMMU_SUPPORT
>  	help
>  	  Driver for the NVIDIA Tegra host1x hardware.
> diff --git a/drivers/gpu/host1x/Makefile b/drivers/gpu/host1x/Makefile
> index b92016ce09b7..ae3a6edf74b4 100644
> --- a/drivers/gpu/host1x/Makefile
> +++ b/drivers/gpu/host1x/Makefile
> @@ -9,6 +9,7 @@ host1x-y = \
>  	job.o \
>  	debug.o \
>  	mipi.o \
> +	fence.o \
>  	hw/host1x01.o \
>  	hw/host1x02.o \
>  	hw/host1x04.o \
> diff --git a/drivers/gpu/host1x/dev.h b/drivers/gpu/host1x/dev.h
> index 43e9fabb43a1..c9071c9c443e 100644
> --- a/drivers/gpu/host1x/dev.h
> +++ b/drivers/gpu/host1x/dev.h
> @@ -1,5 +1,5 @@
>  /*
> - * Copyright (c) 2012-2015, NVIDIA Corporation.
> + * Copyright (C) 2012-2016 NVIDIA CORPORATION.  All rights reserved.
>   *
>   * This program is free software; you can redistribute it and/or modify it
>   * under the terms and conditions of the GNU General Public License,
> @@ -42,6 +42,7 @@ struct host1x_channel_ops {
>  	int (*init)(struct host1x_channel *channel, struct host1x *host,
>  		    unsigned int id);
>  	int (*submit)(struct host1x_job *job);
> +	void (*push_wait)(struct host1x_channel *ch, u32 id, u32 thresh);
>  };
>  
>  struct host1x_cdma_ops {
> @@ -117,6 +118,8 @@ struct host1x {
>  	struct clk *clk;
>  	struct reset_control *rst;
>  
> +	u64 fence_ctx_base;
> +
>  	struct iommu_group *group;
>  	struct iommu_domain *domain;
>  	struct iova_domain iova;
> @@ -250,6 +253,13 @@ static inline int host1x_hw_channel_submit(struct host1x *host,
>  	return host->channel_op->submit(job);
>  }
>  
> +static inline void host1x_hw_channel_push_wait(struct host1x *host,
> +					       struct host1x_channel *channel,
> +					       u32 id, u32 thresh)
> +{
> +	host->channel_op->push_wait(channel, id, thresh);
> +}
> +
>  static inline void host1x_hw_cdma_start(struct host1x *host,
>  					struct host1x_cdma *cdma)
>  {
> diff --git a/drivers/gpu/host1x/fence.c b/drivers/gpu/host1x/fence.c
> new file mode 100644
> index 000000000000..3b056623ea64
> --- /dev/null
> +++ b/drivers/gpu/host1x/fence.c
> @@ -0,0 +1,202 @@
> +/*
> + * Copyright (C) 2016 NVIDIA CORPORATION.  All rights reserved.
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms and conditions of the GNU General Public License,
> + * version 2, as published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope 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.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program.  If not, see <http://www.gnu.org/licenses/>.
> + */
> +
> +#include <linux/dma-fence.h>
> +#include <linux/dma-fence-array.h>
> +#include <linux/slab.h>
> +
> +#include "fence.h"
> +#include "intr.h"
> +#include "syncpt.h"
> +#include "cdma.h"
> +#include "channel.h"
> +#include "dev.h"
> +
> +struct host1x_fence {
> +	struct dma_fence base;
> +	spinlock_t lock;
> +
> +	struct host1x_syncpt *syncpt;
> +	u32 threshold;
> +
> +	struct host1x *host;
> +	void *waiter;
> +
> +	char timeline_name[10];
> +};
> +
> +static inline struct host1x_fence *to_host1x_fence(struct dma_fence *fence)
> +{
> +	return (struct host1x_fence *)fence;
> +}
> +
> +static const char *host1x_fence_get_driver_name(struct dma_fence *fence)
> +{
> +	return "host1x";
> +}
> +
> +static const char *host1x_fence_get_timeline_name(struct dma_fence *fence)
> +{
> +	struct host1x_fence *f = to_host1x_fence(fence);
> +
> +	return f->timeline_name;
> +}
> +
> +static bool host1x_fence_enable_signaling(struct dma_fence *fence)
> +{
> +	struct host1x_fence *f = to_host1x_fence(fence);
> +
> +	if (host1x_syncpt_is_expired(f->syncpt, f->threshold))
> +		return false;
> +
> +	return true;
> +}
> +
> +static bool host1x_fence_signaled(struct dma_fence *fence)
> +{
> +	struct host1x_fence *f = to_host1x_fence(fence);
> +
> +	return host1x_syncpt_is_expired(f->syncpt, f->threshold);
> +}
> +
> +static void host1x_fence_release(struct dma_fence *fence)
> +{
> +	struct host1x_fence *f = to_host1x_fence(fence);
> +
> +	if (f->waiter)
> +		host1x_intr_put_ref(f->host, f->syncpt->id, f->waiter);
> +
> +	kfree(f);
> +}
> +
> +const struct dma_fence_ops host1x_fence_ops = {
> +	.get_driver_name = host1x_fence_get_driver_name,
> +	.get_timeline_name = host1x_fence_get_timeline_name,
> +	.enable_signaling = host1x_fence_enable_signaling,
> +	.signaled = host1x_fence_signaled,
> +	.wait = dma_fence_default_wait,
> +	.release = host1x_fence_release,
> +};
> +
> +static void host1x_fence_wait_single(struct host1x_fence *f,
> +				     struct host1x *host,
> +				     struct host1x_channel *ch)
> +{
> +	if (host1x_syncpt_is_expired(f->syncpt, f->threshold))
> +		return;
> +
> +	host1x_hw_channel_push_wait(host, ch, f->syncpt->id, f->threshold);
> +}
> +
> +/**
> + * host1x_fence_is_waitable() - Check if DMA fence can be waited by hardware
> + * @fence: DMA fence
> + *
> + * Check is @fence is only backed by Host1x syncpoints and can therefore be
> + * waited using only hardware.
> + */
> +bool host1x_fence_is_waitable(struct dma_fence *fence)
> +{
> +	struct dma_fence_array *array;
> +	int i;
> +
> +	array = to_dma_fence_array(fence);
> +	if (!array)
> +		return fence->ops == &host1x_fence_ops;
> +
> +	for (i = 0; i < array->num_fences; ++i) {
> +		if (array->fences[i]->ops != &host1x_fence_ops)
> +			return false;
> +	}
> +
> +	return true;
> +}
> +
> +/**
> + * host1x_fence_wait() - Insert waits for fence into channel
> + * @fence: DMA fence
> + * @host: Host1x
> + * @ch: Host1x channel
> + *
> + * Inserts wait commands into Host1x channel fences in @fence.
> + * in @fence. @fence must only consist of syncpoint-backed fences.
> + *
> + * Return: 0 on success, -errno otherwise.
> + */
> +int host1x_fence_wait(struct dma_fence *fence, struct host1x *host,
> +		      struct host1x_channel *ch)
> +{
> +	struct dma_fence_array *array;
> +	int i = 0;
> +
> +	if (!host1x_fence_is_waitable(fence))
> +		return -EINVAL;
> +
> +	array = to_dma_fence_array(fence);
> +	if (!array) {
> +		host1x_fence_wait_single(to_host1x_fence(fence), host, ch);
> +		return 0;
> +	}
> +
> +	for (i = 0; i < array->num_fences; ++i) {
> +		host1x_fence_wait_single(to_host1x_fence(array->fences[i]),
> +					 host, ch);
> +	}
> +
> +	return 0;
> +}
> +
> +struct dma_fence *host1x_fence_create(struct host1x *host,
> +				      struct host1x_syncpt *syncpt,
> +				      u32 threshold)
> +{
> +	struct host1x_waitlist *waiter;
> +	struct host1x_fence *f;
> +	int err;
> +
> +	f = kzalloc(sizeof(*f), GFP_KERNEL);
> +	if (!f)
> +		return NULL;
> +
> +	waiter = kzalloc(sizeof(*waiter), GFP_KERNEL);
> +	if (!waiter) {
> +		kfree(f);
> +		return NULL;
> +	}
> +
> +	f->host = host;
> +	f->syncpt = syncpt;
> +	f->threshold = threshold;
> +	f->waiter = NULL;
> +	snprintf(f->timeline_name, ARRAY_SIZE(f->timeline_name),
> +		 "%d", syncpt->id);
> +
> +	spin_lock_init(&f->lock);
> +	dma_fence_init(&f->base, &host1x_fence_ops, &f->lock,
> +		       host->fence_ctx_base + syncpt->id, threshold);
> +
> +	err = host1x_intr_add_action(f->host, f->syncpt->id, f->threshold,
> +				     HOST1X_INTR_ACTION_SIGNAL_FENCE, f,
> +				     waiter, &f->waiter);
> +	if (err) {
> +		kfree(waiter);
> +		dma_fence_put((struct dma_fence *)f);
> +		return NULL;
> +	}
> +
> +	return (struct dma_fence *)f;
> +}
> +EXPORT_SYMBOL(host1x_fence_create);
> diff --git a/drivers/gpu/host1x/fence.h b/drivers/gpu/host1x/fence.h
> new file mode 100644
> index 000000000000..5725c95c0f1b
> --- /dev/null
> +++ b/drivers/gpu/host1x/fence.h
> @@ -0,0 +1,28 @@
> +/*
> + * Copyright (C) 2016 NVIDIA CORPORATION.  All rights reserved.
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms and conditions of the GNU General Public License,
> + * version 2, as published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope 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.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program.  If not, see <http://www.gnu.org/licenses/>.
> + */
> +
> +#ifndef __HOST1X_FENCE_H
> +#define __HOST1X_FENCE_H
> +
> +struct host1x;
> +struct host1x_channel;
> +struct dma_fence;
> +
> +bool host1x_fence_is_waitable(struct dma_fence *fence);
> +int host1x_fence_wait(struct dma_fence *fence, struct host1x *host,
> +		      struct host1x_channel *ch);
> +
> +#endif
> diff --git a/drivers/gpu/host1x/hw/channel_hw.c b/drivers/gpu/host1x/hw/channel_hw.c
> index 9af758785a11..d43828902248 100644
> --- a/drivers/gpu/host1x/hw/channel_hw.c
> +++ b/drivers/gpu/host1x/hw/channel_hw.c
> @@ -1,7 +1,7 @@
>  /*
>   * Tegra host1x Channel
>   *
> - * Copyright (c) 2010-2013, NVIDIA Corporation.
> + * Copyright (C) 2010-2016 NVIDIA CORPORATION.  All rights reserved.
>   *
>   * This program is free software; you can redistribute it and/or modify it
>   * under the terms and conditions of the GNU General Public License,
> @@ -16,6 +16,7 @@
>   * along with this program.  If not, see <http://www.gnu.org/licenses/>.
>   */
>  
> +#include <linux/dma-fence.h>
>  #include <linux/host1x.h>
>  #include <linux/slab.h>
>  
> @@ -23,6 +24,7 @@
>  
>  #include "../channel.h"
>  #include "../dev.h"
> +#include "../fence.h"
>  #include "../intr.h"
>  #include "../job.h"
>  
> @@ -68,11 +70,26 @@ static void submit_gathers(struct host1x_job *job)
>  		u32 op1 = host1x_opcode_gather(g->words);
>  		u32 op2 = g->base + g->offset;
>  
> +		/* add a setclass for modules that require it */
> +		if (job->class)
> +			host1x_cdma_push(cdma,
> +				 host1x_opcode_setclass(job->class, 0, 0),
> +				 HOST1X_OPCODE_NOP);
> +
>  		trace_write_gather(cdma, g->bo, g->offset, op1 & 0xffff);
>  		host1x_cdma_push(cdma, op1, op2);
>  	}
>  }
>  
> +static void channel_push_wait(struct host1x_channel *channel,
> +			     u32 id, u32 thresh)
> +{
> +	host1x_cdma_push(&channel->cdma,
> +			 host1x_opcode_setclass(HOST1X_CLASS_HOST1X,
> +				host1x_uclass_wait_syncpt_r(), 1),
> +			 host1x_class_host_wait_syncpt(id, thresh));
> +}
> +
>  static inline void synchronize_syncpt_base(struct host1x_job *job)
>  {
>  	struct host1x *host = dev_get_drvdata(job->channel->dev->parent);
> @@ -110,6 +127,16 @@ static int channel_submit(struct host1x_job *job)
>  	/* before error checks, return current max */
>  	prev_max = job->syncpt_end = host1x_syncpt_read_max(sp);
>  
> +	if (job->prefence) {
> +		if (host1x_fence_is_waitable(job->prefence)) {
> +			host1x_fence_wait(job->prefence, host, job->channel);
> +		} else {
> +			err = dma_fence_wait(job->prefence, true);
> +			if (err)
> +				goto error;
> +		}
> +	}
> +
>  	/* get submit lock */
>  	err = mutex_lock_interruptible(&ch->submitlock);
>  	if (err)
> @@ -151,12 +178,6 @@ static int channel_submit(struct host1x_job *job)
>  
>  	job->syncpt_end = syncval;
>  
> -	/* add a setclass for modules that require it */
> -	if (job->class)
> -		host1x_cdma_push(&ch->cdma,
> -				 host1x_opcode_setclass(job->class, 0, 0),
> -				 HOST1X_OPCODE_NOP);
> -
>  	submit_gathers(job);
>  
>  	/* end CDMA submit & stash pinned hMems into sync queue */
> @@ -212,4 +233,5 @@ static int host1x_channel_init(struct host1x_channel *ch, struct host1x *dev,
>  static const struct host1x_channel_ops host1x_channel_ops = {
>  	.init = host1x_channel_init,
>  	.submit = channel_submit,
> +	.push_wait = channel_push_wait
>  };
> diff --git a/drivers/gpu/host1x/intr.c b/drivers/gpu/host1x/intr.c
> index 8b4fad0ab35d..b3d51288243d 100644
> --- a/drivers/gpu/host1x/intr.c
> +++ b/drivers/gpu/host1x/intr.c
> @@ -1,7 +1,7 @@
>  /*
>   * Tegra host1x Interrupt Management
>   *
> - * Copyright (c) 2010-2013, NVIDIA Corporation.
> + * Copyright (C) 2010-2016 NVIDIA CORPORATION.  All rights reserved.
>   *
>   * This program is free software; you can redistribute it and/or modify it
>   * under the terms and conditions of the GNU General Public License,
> @@ -17,6 +17,7 @@
>   */
>  
>  #include <linux/clk.h>
> +#include <linux/dma-fence.h>
>  #include <linux/interrupt.h>
>  #include <linux/slab.h>
>  #include <linux/irq.h>
> @@ -133,12 +134,20 @@ static void action_wakeup_interruptible(struct host1x_waitlist *waiter)
>  	wake_up_interruptible(wq);
>  }
>  
> +static void action_signal_fence(struct host1x_waitlist *waiter)
> +{
> +	struct dma_fence *fence = waiter->data;
> +
> +	dma_fence_signal(fence);
> +}
> +
>  typedef void (*action_handler)(struct host1x_waitlist *waiter);
>  
>  static const action_handler action_handlers[HOST1X_INTR_ACTION_COUNT] = {
>  	action_submit_complete,
>  	action_wakeup,
>  	action_wakeup_interruptible,
> +	action_signal_fence
>  };
>  
>  static void run_handlers(struct list_head completed[HOST1X_INTR_ACTION_COUNT])
> diff --git a/drivers/gpu/host1x/intr.h b/drivers/gpu/host1x/intr.h
> index 1370c2bb75b8..6b2c090fa91c 100644
> --- a/drivers/gpu/host1x/intr.h
> +++ b/drivers/gpu/host1x/intr.h
> @@ -1,7 +1,7 @@
>  /*
>   * Tegra host1x Interrupt Management
>   *
> - * Copyright (c) 2010-2013, NVIDIA Corporation.
> + * Copyright (C) 2010-2016 NVIDIA CORPORATION.  All rights reserved.
>   *
>   * This program is free software; you can redistribute it and/or modify it
>   * under the terms and conditions of the GNU General Public License,
> @@ -43,6 +43,12 @@ enum host1x_intr_action {
>  	 */
>  	HOST1X_INTR_ACTION_WAKEUP_INTERRUPTIBLE,
>  
> +	/*
> +	 * Signal a dma fence.
> +	 * 'data' points to a host1x_fence
> +	 */
> +	HOST1X_INTR_ACTION_SIGNAL_FENCE,
> +
>  	HOST1X_INTR_ACTION_COUNT
>  };
>  
> diff --git a/drivers/gpu/host1x/syncpt.c b/drivers/gpu/host1x/syncpt.c
> index a2a952adc136..652803b610b2 100644
> --- a/drivers/gpu/host1x/syncpt.c
> +++ b/drivers/gpu/host1x/syncpt.c
> @@ -18,6 +18,7 @@
>  
>  #include <linux/module.h>
>  #include <linux/device.h>
> +#include <linux/dma-fence.h>
>  #include <linux/slab.h>
>  
>  #include <trace/events/host1x.h>
> @@ -413,6 +414,7 @@ int host1x_syncpt_init(struct host1x *host)
>  	mutex_init(&host->syncpt_mutex);
>  	host->syncpt = syncpt;
>  	host->bases = bases;
> +	host->fence_ctx_base = dma_fence_context_alloc(host->info->nb_pts);
>  
>  	host1x_syncpt_restore(host);
>  	host1x_hw_syncpt_enable_protection(host);
> diff --git a/include/linux/host1x.h b/include/linux/host1x.h
> index ddf7f9ca86cc..fd4daa78768f 100644
> --- a/include/linux/host1x.h
> +++ b/include/linux/host1x.h
> @@ -1,5 +1,5 @@
>  /*
> - * Copyright (c) 2009-2013, NVIDIA Corporation. All rights reserved.
> + * Copyright (C) 2009-2016 NVIDIA CORPORATION.  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 as published by
> @@ -71,6 +71,7 @@ struct host1x_client {
>   * host1x buffer objects
>   */
>  
> +struct dma_fence;
>  struct host1x_bo;
>  struct sg_table;
>  
> @@ -258,6 +259,9 @@ struct host1x_job {
>  
>  	/* Add a channel wait for previous ops to complete */
>  	bool serialize;
> +
> +	/* Wait for prefence to complete before submitting */
> +	struct dma_fence *prefence;
>  };
>  
>  struct host1x_job *host1x_job_alloc(struct host1x_channel *ch,
> @@ -343,4 +347,10 @@ int tegra_mipi_enable(struct tegra_mipi_device *device);
>  int tegra_mipi_disable(struct tegra_mipi_device *device);
>  int tegra_mipi_calibrate(struct tegra_mipi_device *device);
>  
> +struct host1x_fence;
> +
> +struct dma_fence *host1x_fence_create(struct host1x *host,
> +				      struct host1x_syncpt *syncpt,
> +				      u32 threshold);
> +
>  #endif
> 

This looks like original version of the Mikko's patch that suffered from racing
condition of fence destruction vs signalling, it also didn't take into account
case of host1x module unload. I've reworked this patch over time a tad, the
current version is here [0], feel free to borrow it if you wish. Note that I
removed waiting for fence on host1x because blocking of whole channel doesn't
feel like a good idea.

[0]
https://github.com/grate-driver/linux/commit/3526b2520154da4d84d3e0dd31cd00aad89b6e2c
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