Re: [PATCH v12 09/13] drm/msm: Add support to create a local pagetable

[Guenter Roeck]

On Mon, Aug 10, 2020 at 04:26:53PM -0600, Jordan Crouse wrote:
> Add support to create a io-pgtable for use by targets that support
> per-instance pagetables. In order to support per-instance pagetables the
> GPU SMMU device needs to have the qcom,adreno-smmu compatible string and
> split pagetables enabled.
> 
> Signed-off-by: Jordan Crouse <jcrouse@xxxxxxxxxxxxxx>

This patch adds a hard dependency on IOMMU_IO_PGTABLE (for
alloc_io_pgtable_ops and free_io_pgtable_ops).

Guenter

> ---
> 
>  drivers/gpu/drm/msm/msm_gpummu.c |   2 +-
>  drivers/gpu/drm/msm/msm_iommu.c  | 190 ++++++++++++++++++++++++++++++-
>  drivers/gpu/drm/msm/msm_mmu.h    |  16 ++-
>  3 files changed, 205 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/gpu/drm/msm/msm_gpummu.c b/drivers/gpu/drm/msm/msm_gpummu.c
> index 310a31b05faa..aab121f4beb7 100644
> --- a/drivers/gpu/drm/msm/msm_gpummu.c
> +++ b/drivers/gpu/drm/msm/msm_gpummu.c
> @@ -102,7 +102,7 @@ struct msm_mmu *msm_gpummu_new(struct device *dev, struct msm_gpu *gpu)
>  	}
>  
>  	gpummu->gpu = gpu;
> -	msm_mmu_init(&gpummu->base, dev, &funcs);
> +	msm_mmu_init(&gpummu->base, dev, &funcs, MSM_MMU_GPUMMU);
>  
>  	return &gpummu->base;
>  }
> diff --git a/drivers/gpu/drm/msm/msm_iommu.c b/drivers/gpu/drm/msm/msm_iommu.c
> index 1b6635504069..bc04dda8a198 100644
> --- a/drivers/gpu/drm/msm/msm_iommu.c
> +++ b/drivers/gpu/drm/msm/msm_iommu.c
> @@ -4,15 +4,201 @@
>   * Author: Rob Clark <robdclark@xxxxxxxxx>
>   */
>  
> +#include <linux/io-pgtable.h>
>  #include "msm_drv.h"
>  #include "msm_mmu.h"
>  
>  struct msm_iommu {
>  	struct msm_mmu base;
>  	struct iommu_domain *domain;
> +	atomic_t pagetables;
>  };
> +
>  #define to_msm_iommu(x) container_of(x, struct msm_iommu, base)
>  
> +struct msm_iommu_pagetable {
> +	struct msm_mmu base;
> +	struct msm_mmu *parent;
> +	struct io_pgtable_ops *pgtbl_ops;
> +	phys_addr_t ttbr;
> +	u32 asid;
> +};
> +static struct msm_iommu_pagetable *to_pagetable(struct msm_mmu *mmu)
> +{
> +	return container_of(mmu, struct msm_iommu_pagetable, base);
> +}
> +
> +static int msm_iommu_pagetable_unmap(struct msm_mmu *mmu, u64 iova,
> +		size_t size)
> +{
> +	struct msm_iommu_pagetable *pagetable = to_pagetable(mmu);
> +	struct io_pgtable_ops *ops = pagetable->pgtbl_ops;
> +	size_t unmapped = 0;
> +
> +	/* Unmap the block one page at a time */
> +	while (size) {
> +		unmapped += ops->unmap(ops, iova, 4096, NULL);
> +		iova += 4096;
> +		size -= 4096;
> +	}
> +
> +	iommu_flush_tlb_all(to_msm_iommu(pagetable->parent)->domain);
> +
> +	return (unmapped == size) ? 0 : -EINVAL;
> +}
> +
> +static int msm_iommu_pagetable_map(struct msm_mmu *mmu, u64 iova,
> +		struct sg_table *sgt, size_t len, int prot)
> +{
> +	struct msm_iommu_pagetable *pagetable = to_pagetable(mmu);
> +	struct io_pgtable_ops *ops = pagetable->pgtbl_ops;
> +	struct scatterlist *sg;
> +	size_t mapped = 0;
> +	u64 addr = iova;
> +	unsigned int i;
> +
> +	for_each_sg(sgt->sgl, sg, sgt->nents, i) {
> +		size_t size = sg->length;
> +		phys_addr_t phys = sg_phys(sg);
> +
> +		/* Map the block one page at a time */
> +		while (size) {
> +			if (ops->map(ops, addr, phys, 4096, prot, GFP_KERNEL)) {
> +				msm_iommu_pagetable_unmap(mmu, iova, mapped);
> +				return -EINVAL;
> +			}
> +
> +			phys += 4096;
> +			addr += 4096;
> +			size -= 4096;
> +			mapped += 4096;
> +		}
> +	}
> +
> +	return 0;
> +}
> +
> +static void msm_iommu_pagetable_destroy(struct msm_mmu *mmu)
> +{
> +	struct msm_iommu_pagetable *pagetable = to_pagetable(mmu);
> +	struct msm_iommu *iommu = to_msm_iommu(pagetable->parent);
> +
> +	/*
> +	 * If this is the last attached pagetable for the parent,
> +	 * disable TTBR0 in the arm-smmu driver
> +	 */
> +	if (atomic_dec_return(&iommu->pagetables) == 0)
> +		iommu_domain_set_attr(iommu->domain,
> +			DOMAIN_ATTR_PGTABLE_CFG, NULL);
> +
> +	free_io_pgtable_ops(pagetable->pgtbl_ops);
> +	kfree(pagetable);
> +}
> +
> +int msm_iommu_pagetable_params(struct msm_mmu *mmu,
> +		phys_addr_t *ttbr, int *asid)
> +{
> +	struct msm_iommu_pagetable *pagetable;
> +
> +	if (mmu->type != MSM_MMU_IOMMU_PAGETABLE)
> +		return -EINVAL;
> +
> +	pagetable = to_pagetable(mmu);
> +
> +	if (ttbr)
> +		*ttbr = pagetable->ttbr;
> +
> +	if (asid)
> +		*asid = pagetable->asid;
> +
> +	return 0;
> +}
> +
> +static const struct msm_mmu_funcs pagetable_funcs = {
> +		.map = msm_iommu_pagetable_map,
> +		.unmap = msm_iommu_pagetable_unmap,
> +		.destroy = msm_iommu_pagetable_destroy,
> +};
> +
> +static void msm_iommu_tlb_flush_all(void *cookie)
> +{
> +}
> +
> +static void msm_iommu_tlb_flush_walk(unsigned long iova, size_t size,
> +		size_t granule, void *cookie)
> +{
> +}
> +
> +static void msm_iommu_tlb_add_page(struct iommu_iotlb_gather *gather,
> +		unsigned long iova, size_t granule, void *cookie)
> +{
> +}
> +
> +static const struct iommu_flush_ops null_tlb_ops = {
> +	.tlb_flush_all = msm_iommu_tlb_flush_all,
> +	.tlb_flush_walk = msm_iommu_tlb_flush_walk,
> +	.tlb_flush_leaf = msm_iommu_tlb_flush_walk,
> +	.tlb_add_page = msm_iommu_tlb_add_page,
> +};
> +
> +struct msm_mmu *msm_iommu_pagetable_create(struct msm_mmu *parent)
> +{
> +	struct msm_iommu *iommu = to_msm_iommu(parent);
> +	static int next_asid = 16;
> +	struct msm_iommu_pagetable *pagetable;
> +	struct io_pgtable_cfg cfg;
> +	int ret;
> +
> +	/* Get the pagetable configuration from the domain */
> +	ret = iommu_domain_get_attr(iommu->domain,
> +		DOMAIN_ATTR_PGTABLE_CFG, &cfg);
> +	if (ret)
> +		return ERR_PTR(ret);
> +
> +	pagetable = kzalloc(sizeof(*pagetable), GFP_KERNEL);
> +	if (!pagetable)
> +		return ERR_PTR(-ENOMEM);
> +
> +	msm_mmu_init(&pagetable->base, parent->dev, &pagetable_funcs,
> +		MSM_MMU_IOMMU_PAGETABLE);
> +
> +	/* The incoming cfg will have the TTBR1 quirk enabled */
> +	cfg.quirks &= ~IO_PGTABLE_QUIRK_ARM_TTBR1;
> +	cfg.tlb = &null_tlb_ops;
> +
> +	pagetable->pgtbl_ops = alloc_io_pgtable_ops(ARM_64_LPAE_S1,
> +		&cfg, iommu->domain);
> +
> +	if (!pagetable->pgtbl_ops) {
> +		kfree(pagetable);
> +		return ERR_PTR(-ENOMEM);
> +	}
> +
> +	/*
> +	 * If this is the first pagetable that we've allocated, send it back to
> +	 * the arm-smmu driver as a trigger to set up TTBR0
> +	 */
> +	if (atomic_inc_return(&iommu->pagetables) == 1) {
> +		ret = iommu_domain_set_attr(iommu->domain,
> +			DOMAIN_ATTR_PGTABLE_CFG, &cfg);
> +		if (ret) {
> +			free_io_pgtable_ops(pagetable->pgtbl_ops);
> +			kfree(pagetable);
> +			return ERR_PTR(ret);
> +		}
> +	}
> +
> +	/* Needed later for TLB flush */
> +	pagetable->parent = parent;
> +	pagetable->ttbr = cfg.arm_lpae_s1_cfg.ttbr;
> +
> +	pagetable->asid = next_asid;
> +	next_asid = (next_asid + 1) % 255;
> +	next_asid = min(16, next_asid);
> +
> +	return &pagetable->base;
> +}
> +
>  static int msm_fault_handler(struct iommu_domain *domain, struct device *dev,
>  		unsigned long iova, int flags, void *arg)
>  {
> @@ -85,9 +271,11 @@ struct msm_mmu *msm_iommu_new(struct device *dev, struct iommu_domain *domain)
>  		return ERR_PTR(-ENOMEM);
>  
>  	iommu->domain = domain;
> -	msm_mmu_init(&iommu->base, dev, &funcs);
> +	msm_mmu_init(&iommu->base, dev, &funcs, MSM_MMU_IOMMU);
>  	iommu_set_fault_handler(domain, msm_fault_handler, iommu);
>  
> +	atomic_set(&iommu->pagetables, 0);
> +
>  	ret = iommu_attach_device(iommu->domain, dev);
>  	if (ret) {
>  		kfree(iommu);
> diff --git a/drivers/gpu/drm/msm/msm_mmu.h b/drivers/gpu/drm/msm/msm_mmu.h
> index 3a534ee59bf6..61ade89d9e48 100644
> --- a/drivers/gpu/drm/msm/msm_mmu.h
> +++ b/drivers/gpu/drm/msm/msm_mmu.h
> @@ -17,18 +17,26 @@ struct msm_mmu_funcs {
>  	void (*destroy)(struct msm_mmu *mmu);
>  };
>  
> +enum msm_mmu_type {
> +	MSM_MMU_GPUMMU,
> +	MSM_MMU_IOMMU,
> +	MSM_MMU_IOMMU_PAGETABLE,
> +};
> +
>  struct msm_mmu {
>  	const struct msm_mmu_funcs *funcs;
>  	struct device *dev;
>  	int (*handler)(void *arg, unsigned long iova, int flags);
>  	void *arg;
> +	enum msm_mmu_type type;
>  };
>  
>  static inline void msm_mmu_init(struct msm_mmu *mmu, struct device *dev,
> -		const struct msm_mmu_funcs *funcs)
> +		const struct msm_mmu_funcs *funcs, enum msm_mmu_type type)
>  {
>  	mmu->dev = dev;
>  	mmu->funcs = funcs;
> +	mmu->type = type;
>  }
>  
>  struct msm_mmu *msm_iommu_new(struct device *dev, struct iommu_domain *domain);
> @@ -41,7 +49,13 @@ static inline void msm_mmu_set_fault_handler(struct msm_mmu *mmu, void *arg,
>  	mmu->handler = handler;
>  }
>  
> +struct msm_mmu *msm_iommu_pagetable_create(struct msm_mmu *parent);
> +
>  void msm_gpummu_params(struct msm_mmu *mmu, dma_addr_t *pt_base,
>  		dma_addr_t *tran_error);
>  
> +
> +int msm_iommu_pagetable_params(struct msm_mmu *mmu, phys_addr_t *ttbr,
> +		int *asid);
> +
>  #endif /* __MSM_MMU_H__ */