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Commit 58fd9375 authored by Alexandre Courbot's avatar Alexandre Courbot Committed by Ben Skeggs
Browse files

drm/nouveau/platform: probe IOMMU if present 



Tegra SoCs have an IOMMU that can be used to present non-contiguous
physical memory as contiguous to the GPU and maximize the use of large
pages in the GPU MMU, leading to performance gains. This patch adds
support for probing such a IOMMU if present and make its properties
available in the nouveau_platform_gpu structure so subsystems can take
advantage of it.

Signed-off-by: default avatarAlexandre Courbot <acourbot@nvidia.com>
Signed-off-by: default avatarBen Skeggs <bskeggs@redhat.com>
parent 5dc240bc

drivers/gpu/drm/nouveau/nouveau_platform.c

+74 −1
Original line number Original line Diff line number Diff line
@@ -27,6 +27,7 @@ 
#include <linux/of.h>

#include <linux/of.h>

#include <linux/reset.h>

#include <linux/reset.h>

#include <linux/regulator/consumer.h>

#include <linux/regulator/consumer.h>

#include <linux/iommu.h>

#include <soc/tegra/fuse.h>

#include <soc/tegra/fuse.h>

#include <soc/tegra/pmc.h>

#include <soc/tegra/pmc.h>
@@ -91,6 +92,71 @@ static int nouveau_platform_power_down(struct nouveau_platform_gpu *gpu) 
	return 0;

	return 0;

}

}





static void nouveau_platform_probe_iommu(struct device *dev,

					 struct nouveau_platform_gpu *gpu)

{

	int err;

	unsigned long pgsize_bitmap;



	mutex_init(&gpu->iommu.mutex);



	if (iommu_present(&platform_bus_type)) {

		gpu->iommu.domain = iommu_domain_alloc(&platform_bus_type);

		if (IS_ERR(gpu->iommu.domain))

			goto error;



		/*

		 * A IOMMU is only usable if it supports page sizes smaller

		 * or equal to the system's PAGE_SIZE, with a preference if

		 * both are equal.

		 */

		pgsize_bitmap = gpu->iommu.domain->ops->pgsize_bitmap;

		if (pgsize_bitmap & PAGE_SIZE) {

			gpu->iommu.pgshift = PAGE_SHIFT;

		} else {

			gpu->iommu.pgshift = fls(pgsize_bitmap & ~PAGE_MASK);

			if (gpu->iommu.pgshift == 0) {

				dev_warn(dev, "unsupported IOMMU page size\n");

				goto free_domain;

			}

			gpu->iommu.pgshift -= 1;

		}



		err = iommu_attach_device(gpu->iommu.domain, dev);

		if (err)

			goto free_domain;



		err = nvkm_mm_init(&gpu->iommu._mm, 0,

				   (1ULL << 40) >> gpu->iommu.pgshift, 1);

		if (err)

			goto detach_device;



		gpu->iommu.mm = &gpu->iommu._mm;

	}



	return;



detach_device:

	iommu_detach_device(gpu->iommu.domain, dev);



free_domain:

	iommu_domain_free(gpu->iommu.domain);



error:

	gpu->iommu.domain = NULL;

	gpu->iommu.pgshift = 0;

	dev_err(dev, "cannot initialize IOMMU MM\n");

}



static void nouveau_platform_remove_iommu(struct device *dev,

					  struct nouveau_platform_gpu *gpu)

{

	if (gpu->iommu.domain) {

		iommu_detach_device(gpu->iommu.domain, dev);

		iommu_domain_free(gpu->iommu.domain);

	}

}



static int nouveau_platform_probe(struct platform_device *pdev)

static int nouveau_platform_probe(struct platform_device *pdev)

{

{

	struct nouveau_platform_gpu *gpu;

	struct nouveau_platform_gpu *gpu;
@@ -118,6 +184,8 @@ static int nouveau_platform_probe(struct platform_device *pdev) 
	if (IS_ERR(gpu->clk_pwr))

	if (IS_ERR(gpu->clk_pwr))

		return PTR_ERR(gpu->clk_pwr);

		return PTR_ERR(gpu->clk_pwr);





	nouveau_platform_probe_iommu(&pdev->dev, gpu);



	err = nouveau_platform_power_up(gpu);

	err = nouveau_platform_power_up(gpu);

	if (err)

	if (err)

		return err;

		return err;
@@ -154,10 +222,15 @@ static int nouveau_platform_remove(struct platform_device *pdev) 
	struct nouveau_drm *drm = nouveau_drm(drm_dev);

	struct nouveau_drm *drm = nouveau_drm(drm_dev);

	struct nvkm_device *device = nvxx_device(&drm->device);

	struct nvkm_device *device = nvxx_device(&drm->device);

	struct nouveau_platform_gpu *gpu = nv_device_to_platform(device)->gpu;

	struct nouveau_platform_gpu *gpu = nv_device_to_platform(device)->gpu;

	int err;





	nouveau_drm_device_remove(drm_dev);

	nouveau_drm_device_remove(drm_dev);





	return nouveau_platform_power_down(gpu);

	err = nouveau_platform_power_down(gpu);



	nouveau_platform_remove_iommu(&pdev->dev, gpu);



	return err;

}

}





#if IS_ENABLED(CONFIG_OF)

#if IS_ENABLED(CONFIG_OF)

drivers/gpu/drm/nouveau/nouveau_platform.h

+18 −0
Original line number Original line Diff line number Diff line
@@ -24,10 +24,12 @@ 
#define __NOUVEAU_PLATFORM_H__

#define __NOUVEAU_PLATFORM_H__





#include "core/device.h"

#include "core/device.h"

#include "core/mm.h"





struct reset_control;

struct reset_control;

struct clk;

struct clk;

struct regulator;

struct regulator;

struct iommu_domain;

struct platform_driver;

struct platform_driver;





struct nouveau_platform_gpu {

struct nouveau_platform_gpu {
@@ -36,6 +38,22 @@ struct nouveau_platform_gpu { 
	struct clk *clk_pwr;

	struct clk *clk_pwr;





	struct regulator *vdd;

	struct regulator *vdd;



	struct {

		/*

		 * Protects accesses to mm from subsystems

		 */

		struct mutex mutex;



		struct nvkm_mm _mm;

		/*

		 * Just points to _mm. We need this to avoid embedding

		 * struct nvkm_mm in os.h

		 */

		struct nvkm_mm *mm;

		struct iommu_domain *domain;

		unsigned long pgshift;

	} iommu;

};

};





struct nouveau_platform_device {

struct nouveau_platform_device {