Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Subject: Re: [PATCH] powerpc/powernv: remove dead npu-dma code
To:     Christoph Hellwig <hch@lst.de>,
        Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        Paul Mackerras <paulus@samba.org>,
        Michael Ellerman <mpe@ellerman.id.au>
Cc:     James Bottomley <jejb@linux.vnet.ibm.com>,
        "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org
References: <20181030133122.GA31102@lst.de>
From:   Alexey Kardashevskiy <aik@ozlabs.ru>
Openpgp: preference=signencrypt
Autocrypt: addr=aik@ozlabs.ru; keydata=
 xsFNBE+rT0sBEADFEI2UtPRsLLvnRf+tI9nA8T91+jDK3NLkqV+2DKHkTGPP5qzDZpRSH6mD
 EePO1JqpVuIow/wGud9xaPA5uvuVgRS1q7RU8otD+7VLDFzPRiRE4Jfr2CW89Ox6BF+q5ZPV
 /pS4v4G9eOrw1v09lEKHB9WtiBVhhxKK1LnUjPEH3ifkOkgW7jFfoYgTdtB3XaXVgYnNPDFo
 PTBYsJy+wr89XfyHr2Ev7BB3Xaf7qICXdBF8MEVY8t/UFsesg4wFWOuzCfqxFmKEaPDZlTuR
 tfLAeVpslNfWCi5ybPlowLx6KJqOsI9R2a9o4qRXWGP7IwiMRAC3iiPyk9cknt8ee6EUIxI6
 t847eFaVKI/6WcxhszI0R6Cj+N4y+1rHfkGWYWupCiHwj9DjILW9iEAncVgQmkNPpUsZECLT
 WQzMuVSxjuXW4nJ6f4OFHqL2dU//qR+BM/eJ0TT3OnfLcPqfucGxubhT7n/CXUxEy+mvWwnm
 s9p4uqVpTfEuzQ0/bE6t7dZdPBua7eYox1AQnk8JQDwC3Rn9kZq2O7u5KuJP5MfludMmQevm
 pHYEMF4vZuIpWcOrrSctJfIIEyhDoDmR34bCXAZfNJ4p4H6TPqPh671uMQV82CfTxTrMhGFq
 8WYU2AH86FrVQfWoH09z1WqhlOm/KZhAV5FndwVjQJs1MRXD8QARAQABzSRBbGV4ZXkgS2Fy
 ZGFzaGV2c2tpeSA8YWlrQG96bGFicy5ydT7CwXgEEwECACIFAk+rT0sCGwMGCwkIBwMCBhUI
 AgkKCwQWAgMBAh4BAheAAAoJEIYTPdgrwSC5fAIP/0wf/oSYaCq9PhO0UP9zLSEz66SSZUf7
 AM9O1rau1lJpT8RoNa0hXFXIVbqPPKPZgorQV8SVmYRLr0oSmPnTiZC82x2dJGOR8x4E01gK
 TanY53J/Z6+CpYykqcIpOlGsytUTBA+AFOpdaFxnJ9a8p2wA586fhCZHVpV7W6EtUPH1SFTQ
 q5xvBmr3KkWGjz1FSLH4FeB70zP6uyuf/B2KPmdlPkyuoafl2UrU8LBADi/efc53PZUAREih
 sm3ch4AxaL4QIWOmlE93S+9nHZSRo9jgGXB1LzAiMRII3/2Leg7O4hBHZ9Nki8/fbDo5///+
 kD4L7UNbSUM/ACWHhd4m1zkzTbyRzvL8NAVQ3rckLOmju7Eu9whiPueGMi5sihy9VQKHmEOx
 OMEhxLRQbzj4ypRLS9a+oxk1BMMu9cd/TccNy0uwx2UUjDQw/cXw2rRWTRCxoKmUsQ+eNWEd
 iYLW6TCfl9CfHlT6A7Zmeqx2DCeFafqEd69DqR9A8W5rx6LQcl0iOlkNqJxxbbW3ddDsLU/Y
 r4cY20++WwOhSNghhtrroP+gouTOIrNE/tvG16jHs8nrYBZuc02nfX1/gd8eguNfVX/ZTHiR
 gHBWe40xBKwBEK2UeqSpeVTohYWGBkcd64naGtK9qHdo1zY1P55lHEc5Uhlk743PgAnOi27Q
 ns5zzsFNBE+rT0sBEACnV6GBSm+25ACT+XAE0t6HHAwDy+UKfPNaQBNTTt31GIk5aXb2Kl/p
 AgwZhQFEjZwDbl9D/f2GtmUHWKcCmWsYd5M/6Ljnbp0Ti5/xi6FyfqnO+G/wD2VhGcKBId1X
 Em/B5y1kZVbzcGVjgD3HiRTqE63UPld45bgK2XVbi2+x8lFvzuFq56E3ZsJZ+WrXpArQXib2
 hzNFwQleq/KLBDOqTT7H+NpjPFR09Qzfa7wIU6pMNF2uFg5ihb+KatxgRDHg70+BzQfa6PPA
 o1xioKXW1eHeRGMmULM0Eweuvpc7/STD3K7EJ5bBq8svoXKuRxoWRkAp9Ll65KTUXgfS+c0x
 gkzJAn8aTG0z/oEJCKPJ08CtYQ5j7AgWJBIqG+PpYrEkhjzSn+DZ5Yl8r+JnZ2cJlYsUHAB9
 jwBnWmLCR3gfop65q84zLXRQKWkASRhBp4JK3IS2Zz7Nd/Sqsowwh8x+3/IUxVEIMaVoUaxk
 Wt8kx40h3VrnLTFRQwQChm/TBtXqVFIuv7/Mhvvcq11xnzKjm2FCnTvCh6T2wJw3de6kYjCO
 7wsaQ2y3i1Gkad45S0hzag/AuhQJbieowKecuI7WSeV8AOFVHmgfhKti8t4Ff758Z0tw5Fpc
 BFDngh6Lty9yR/fKrbkkp6ux1gJ2QncwK1v5kFks82Cgj+DSXK6GUQARAQABwsFfBBgBAgAJ
 BQJPq09LAhsMAAoJEIYTPdgrwSC5NYEP/2DmcEa7K9A+BT2+G5GXaaiFa098DeDrnjmRvumJ
 BhA1UdZRdfqICBADmKHlJjj2xYo387sZpS6ABbhrFxM6s37g/pGPvFUFn49C47SqkoGcbeDz
 Ha7JHyYUC+Tz1dpB8EQDh5xHMXj7t59mRDgsZ2uVBKtXj2ZkbizSHlyoeCfs1gZKQgQE8Ffc
 F8eWKoqAQtn3j4nE3RXbxzTJJfExjFB53vy2wV48fUBdyoXKwE85fiPglQ8bU++0XdOr9oyy
 j1llZlB9t3tKVv401JAdX8EN0++ETiOovQdzE1m+6ioDCtKEx84ObZJM0yGSEGEanrWjiwsa
 nzeK0pJQM9EwoEYi8TBGhHC9ksaAAQipSH7F2OHSYIlYtd91QoiemgclZcSgrxKSJhyFhmLr
 QEiEILTKn/pqJfhHU/7R7UtlDAmFMUp7ByywB4JLcyD10lTmrEJ0iyRRTVfDrfVP82aMBXgF
 tKQaCxcmLCaEtrSrYGzd1sSPwJne9ssfq0SE/LM1J7VdCjm6OWV33SwKrfd6rOtvOzgadrG6
 3bgUVBw+bsXhWDd8tvuCXmdY4bnUblxF2B6GOwSY43v6suugBttIyW5Bl2tXSTwP+zQisOJo
 +dpVG2pRr39h+buHB3NY83NEPXm1kUOhduJUA17XUY6QQCAaN4sdwPqHq938S3EmtVhs
Message-ID: <2c87f9d2-3beb-6c7e-71a4-db8a905f57b1@ozlabs.ru>
Date:   Thu, 1 Nov 2018 15:41:02 +1100
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101
 Thunderbird/60.2.1
MIME-Version: 1.0
In-Reply-To: <20181030133122.GA31102@lst.de>
Content-Type: text/plain; charset=utf-8
Content-Language: en-US
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk


On 31/10/2018 00:31, Christoph Hellwig wrote:
> This code has never been unused in the kernel since it was merged, and
> there has been no attempt that I could find to even submit users for
> it.  Besides the general policy of not keep 1000+ lines of dead
> code, it helps cleaning up the DMA code and making powerpc user common
> infrastructure.
> 
> This effectively reverts commit 5d2aa710 ("powerpc/powernv: Add support
> for Nvlink NPUs").
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
> 
> [this is a follow up to the brief maintainer summit discussion]
> 
>  arch/powerpc/include/asm/pci.h            |   3 -
>  arch/powerpc/include/asm/powernv.h        |  23 -
>  arch/powerpc/platforms/powernv/Makefile   |   2 +-
>  arch/powerpc/platforms/powernv/npu-dma.c  | 989 ----------------------
>  arch/powerpc/platforms/powernv/pci-ioda.c | 243 ------
>  arch/powerpc/platforms/powernv/pci.h      |  11 -
>  6 files changed, 1 insertion(+), 1270 deletions(-)
>  delete mode 100644 arch/powerpc/platforms/powernv/npu-dma.c
> 
> diff --git a/arch/powerpc/include/asm/pci.h b/arch/powerpc/include/asm/pci.h
> index 2af9ded80540..a01d2e3d6ff9 100644
> --- a/arch/powerpc/include/asm/pci.h
> +++ b/arch/powerpc/include/asm/pci.h
> @@ -127,7 +127,4 @@ extern void pcibios_scan_phb(struct pci_controller *hose);
>  
>  #endif	/* __KERNEL__ */
>  
> -extern struct pci_dev *pnv_pci_get_gpu_dev(struct pci_dev *npdev);
> -extern struct pci_dev *pnv_pci_get_npu_dev(struct pci_dev *gpdev, int index);
> -
>  #endif /* __ASM_POWERPC_PCI_H */
> diff --git a/arch/powerpc/include/asm/powernv.h b/arch/powerpc/include/asm/powernv.h
> index 2f3ff7a27881..4848a6b3c6b2 100644
> --- a/arch/powerpc/include/asm/powernv.h
> +++ b/arch/powerpc/include/asm/powernv.h
> @@ -11,33 +11,10 @@
>  #define _ASM_POWERNV_H
>  
>  #ifdef CONFIG_PPC_POWERNV
> -#define NPU2_WRITE 1
>  extern void powernv_set_nmmu_ptcr(unsigned long ptcr);
> -extern struct npu_context *pnv_npu2_init_context(struct pci_dev *gpdev,
> -			unsigned long flags,
> -			void (*cb)(struct npu_context *, void *),
> -			void *priv);
> -extern void pnv_npu2_destroy_context(struct npu_context *context,
> -				struct pci_dev *gpdev);
> -extern int pnv_npu2_handle_fault(struct npu_context *context, uintptr_t *ea,
> -				unsigned long *flags, unsigned long *status,
> -				int count);
> -
>  void pnv_tm_init(void);
>  #else
>  static inline void powernv_set_nmmu_ptcr(unsigned long ptcr) { }
> -static inline struct npu_context *pnv_npu2_init_context(struct pci_dev *gpdev,
> -			unsigned long flags,
> -			struct npu_context *(*cb)(struct npu_context *, void *),
> -			void *priv) { return ERR_PTR(-ENODEV); }
> -static inline void pnv_npu2_destroy_context(struct npu_context *context,
> -					struct pci_dev *gpdev) { }
> -
> -static inline int pnv_npu2_handle_fault(struct npu_context *context,
> -					uintptr_t *ea, unsigned long *flags,
> -					unsigned long *status, int count) {
> -	return -ENODEV;
> -}
>  
>  static inline void pnv_tm_init(void) { }
>  static inline void pnv_power9_force_smt4(void) { }
> diff --git a/arch/powerpc/platforms/powernv/Makefile b/arch/powerpc/platforms/powernv/Makefile
> index b540ce8eec55..2b13e9dd137c 100644
> --- a/arch/powerpc/platforms/powernv/Makefile
> +++ b/arch/powerpc/platforms/powernv/Makefile
> @@ -6,7 +6,7 @@ obj-y			+= opal-msglog.o opal-hmi.o opal-power.o opal-irqchip.o
>  obj-y			+= opal-kmsg.o opal-powercap.o opal-psr.o opal-sensor-groups.o
>  
>  obj-$(CONFIG_SMP)	+= smp.o subcore.o subcore-asm.o
> -obj-$(CONFIG_PCI)	+= pci.o pci-ioda.o npu-dma.o pci-ioda-tce.o
> +obj-$(CONFIG_PCI)	+= pci.o pci-ioda.o pci-ioda-tce.o
>  obj-$(CONFIG_CXL_BASE)	+= pci-cxl.o
>  obj-$(CONFIG_EEH)	+= eeh-powernv.o
>  obj-$(CONFIG_PPC_SCOM)	+= opal-xscom.o
> diff --git a/arch/powerpc/platforms/powernv/npu-dma.c b/arch/powerpc/platforms/powernv/npu-dma.c
> deleted file mode 100644
> index 6f60e0931922..000000000000
> --- a/arch/powerpc/platforms/powernv/npu-dma.c
> +++ /dev/null
> @@ -1,989 +0,0 @@
> -/*
> - * This file implements the DMA operations for NVLink devices. The NPU
> - * devices all point to the same iommu table as the parent PCI device.
> - *
> - * Copyright Alistair Popple, IBM Corporation 2015.
> - *
> - * This program is free software; you can redistribute it and/or
> - * modify it under the terms of version 2 of the GNU General Public
> - * License as published by the Free Software Foundation.
> - */
> -
> -#include <linux/slab.h>
> -#include <linux/mmu_notifier.h>
> -#include <linux/mmu_context.h>
> -#include <linux/of.h>
> -#include <linux/export.h>
> -#include <linux/pci.h>
> -#include <linux/memblock.h>
> -#include <linux/iommu.h>
> -#include <linux/sizes.h>
> -
> -#include <asm/debugfs.h>
> -#include <asm/tlb.h>
> -#include <asm/powernv.h>
> -#include <asm/reg.h>
> -#include <asm/opal.h>
> -#include <asm/io.h>
> -#include <asm/iommu.h>
> -#include <asm/pnv-pci.h>
> -#include <asm/msi_bitmap.h>
> -#include <asm/opal.h>
> -
> -#include "powernv.h"
> -#include "pci.h"
> -
> -#define npu_to_phb(x) container_of(x, struct pnv_phb, npu)
> -
> -/*
> - * spinlock to protect initialisation of an npu_context for a particular
> - * mm_struct.
> - */
> -static DEFINE_SPINLOCK(npu_context_lock);
> -
> -/*
> - * Other types of TCE cache invalidation are not functional in the
> - * hardware.
> - */
> -static struct pci_dev *get_pci_dev(struct device_node *dn)
> -{
> -	struct pci_dn *pdn = PCI_DN(dn);
> -
> -	return pci_get_domain_bus_and_slot(pci_domain_nr(pdn->phb->bus),
> -					   pdn->busno, pdn->devfn);
> -}
> -
> -/* Given a NPU device get the associated PCI device. */
> -struct pci_dev *pnv_pci_get_gpu_dev(struct pci_dev *npdev)
> -{
> -	struct device_node *dn;
> -	struct pci_dev *gpdev;
> -
> -	if (WARN_ON(!npdev))
> -		return NULL;
> -
> -	if (WARN_ON(!npdev->dev.of_node))
> -		return NULL;
> -
> -	/* Get assoicated PCI device */
> -	dn = of_parse_phandle(npdev->dev.of_node, "ibm,gpu", 0);
> -	if (!dn)
> -		return NULL;
> -
> -	gpdev = get_pci_dev(dn);
> -	of_node_put(dn);
> -
> -	return gpdev;
> -}
> -EXPORT_SYMBOL(pnv_pci_get_gpu_dev);
> -
> -/* Given the real PCI device get a linked NPU device. */
> -struct pci_dev *pnv_pci_get_npu_dev(struct pci_dev *gpdev, int index)
> -{
> -	struct device_node *dn;
> -	struct pci_dev *npdev;
> -
> -	if (WARN_ON(!gpdev))
> -		return NULL;
> -
> -	/* Not all PCI devices have device-tree nodes */
> -	if (!gpdev->dev.of_node)
> -		return NULL;
> -
> -	/* Get assoicated PCI device */
> -	dn = of_parse_phandle(gpdev->dev.of_node, "ibm,npu", index);
> -	if (!dn)
> -		return NULL;
> -
> -	npdev = get_pci_dev(dn);
> -	of_node_put(dn);
> -
> -	return npdev;
> -}
> -EXPORT_SYMBOL(pnv_pci_get_npu_dev);
> -
> -#define NPU_DMA_OP_UNSUPPORTED()					\
> -	dev_err_once(dev, "%s operation unsupported for NVLink devices\n", \
> -		__func__)
> -
> -static void *dma_npu_alloc(struct device *dev, size_t size,
> -			   dma_addr_t *dma_handle, gfp_t flag,
> -			   unsigned long attrs)
> -{
> -	NPU_DMA_OP_UNSUPPORTED();
> -	return NULL;
> -}
> -
> -static void dma_npu_free(struct device *dev, size_t size,
> -			 void *vaddr, dma_addr_t dma_handle,
> -			 unsigned long attrs)
> -{
> -	NPU_DMA_OP_UNSUPPORTED();
> -}
> -
> -static dma_addr_t dma_npu_map_page(struct device *dev, struct page *page,
> -				   unsigned long offset, size_t size,
> -				   enum dma_data_direction direction,
> -				   unsigned long attrs)
> -{
> -	NPU_DMA_OP_UNSUPPORTED();
> -	return 0;
> -}
> -
> -static int dma_npu_map_sg(struct device *dev, struct scatterlist *sglist,
> -			  int nelems, enum dma_data_direction direction,
> -			  unsigned long attrs)
> -{
> -	NPU_DMA_OP_UNSUPPORTED();
> -	return 0;
> -}
> -
> -static int dma_npu_dma_supported(struct device *dev, u64 mask)
> -{
> -	NPU_DMA_OP_UNSUPPORTED();
> -	return 0;
> -}
> -
> -static u64 dma_npu_get_required_mask(struct device *dev)
> -{
> -	NPU_DMA_OP_UNSUPPORTED();
> -	return 0;
> -}
> -
> -static const struct dma_map_ops dma_npu_ops = {
> -	.map_page		= dma_npu_map_page,
> -	.map_sg			= dma_npu_map_sg,
> -	.alloc			= dma_npu_alloc,
> -	.free			= dma_npu_free,
> -	.dma_supported		= dma_npu_dma_supported,
> -	.get_required_mask	= dma_npu_get_required_mask,
> -};
> -
> -/*
> - * Returns the PE assoicated with the PCI device of the given
> - * NPU. Returns the linked pci device if pci_dev != NULL.
> - */
> -static struct pnv_ioda_pe *get_gpu_pci_dev_and_pe(struct pnv_ioda_pe *npe,
> -						  struct pci_dev **gpdev)
> -{
> -	struct pnv_phb *phb;
> -	struct pci_controller *hose;
> -	struct pci_dev *pdev;
> -	struct pnv_ioda_pe *pe;
> -	struct pci_dn *pdn;
> -
> -	pdev = pnv_pci_get_gpu_dev(npe->pdev);
> -	if (!pdev)
> -		return NULL;
> -
> -	pdn = pci_get_pdn(pdev);
> -	if (WARN_ON(!pdn || pdn->pe_number == IODA_INVALID_PE))
> -		return NULL;
> -
> -	hose = pci_bus_to_host(pdev->bus);
> -	phb = hose->private_data;
> -	pe = &phb->ioda.pe_array[pdn->pe_number];
> -
> -	if (gpdev)
> -		*gpdev = pdev;
> -
> -	return pe;
> -}
> -
> -long pnv_npu_set_window(struct pnv_ioda_pe *npe, int num,
> -		struct iommu_table *tbl)
> -{
> -	struct pnv_phb *phb = npe->phb;
> -	int64_t rc;
> -	const unsigned long size = tbl->it_indirect_levels ?
> -		tbl->it_level_size : tbl->it_size;
> -	const __u64 start_addr = tbl->it_offset << tbl->it_page_shift;
> -	const __u64 win_size = tbl->it_size << tbl->it_page_shift;
> -
> -	pe_info(npe, "Setting up window %llx..%llx pg=%lx\n",
> -			start_addr, start_addr + win_size - 1,
> -			IOMMU_PAGE_SIZE(tbl));
> -
> -	rc = opal_pci_map_pe_dma_window(phb->opal_id,
> -			npe->pe_number,
> -			npe->pe_number,
> -			tbl->it_indirect_levels + 1,
> -			__pa(tbl->it_base),
> -			size << 3,
> -			IOMMU_PAGE_SIZE(tbl));
> -	if (rc) {
> -		pe_err(npe, "Failed to configure TCE table, err %lld\n", rc);
> -		return rc;
> -	}
> -	pnv_pci_ioda2_tce_invalidate_entire(phb, false);
> -
> -	/* Add the table to the list so its TCE cache will get invalidated */
> -	pnv_pci_link_table_and_group(phb->hose->node, num,
> -			tbl, &npe->table_group);
> -
> -	return 0;
> -}
> -
> -long pnv_npu_unset_window(struct pnv_ioda_pe *npe, int num)
> -{
> -	struct pnv_phb *phb = npe->phb;
> -	int64_t rc;
> -
> -	pe_info(npe, "Removing DMA window\n");
> -
> -	rc = opal_pci_map_pe_dma_window(phb->opal_id, npe->pe_number,
> -			npe->pe_number,
> -			0/* levels */, 0/* table address */,
> -			0/* table size */, 0/* page size */);
> -	if (rc) {
> -		pe_err(npe, "Unmapping failed, ret = %lld\n", rc);
> -		return rc;
> -	}
> -	pnv_pci_ioda2_tce_invalidate_entire(phb, false);
> -
> -	pnv_pci_unlink_table_and_group(npe->table_group.tables[num],
> -			&npe->table_group);
> -
> -	return 0;
> -}
> -
> -/*
> - * Enables 32 bit DMA on NPU.
> - */
> -static void pnv_npu_dma_set_32(struct pnv_ioda_pe *npe)
> -{
> -	struct pci_dev *gpdev;
> -	struct pnv_ioda_pe *gpe;
> -	int64_t rc;
> -
> -	/*
> -	 * Find the assoicated PCI devices and get the dma window
> -	 * information from there.
> -	 */
> -	if (!npe->pdev || !(npe->flags & PNV_IODA_PE_DEV))
> -		return;
> -
> -	gpe = get_gpu_pci_dev_and_pe(npe, &gpdev);
> -	if (!gpe)
> -		return;
> -
> -	rc = pnv_npu_set_window(npe, 0, gpe->table_group.tables[0]);
> -
> -	/*
> -	 * We don't initialise npu_pe->tce32_table as we always use
> -	 * dma_npu_ops which are nops.
> -	 */
> -	set_dma_ops(&npe->pdev->dev, &dma_npu_ops);
> -}
> -
> -/*
> - * Enables bypass mode on the NPU. The NPU only supports one
> - * window per link, so bypass needs to be explicitly enabled or
> - * disabled. Unlike for a PHB3 bypass and non-bypass modes can't be
> - * active at the same time.
> - */
> -static int pnv_npu_dma_set_bypass(struct pnv_ioda_pe *npe)
> -{
> -	struct pnv_phb *phb = npe->phb;
> -	int64_t rc = 0;
> -	phys_addr_t top = memblock_end_of_DRAM();
> -
> -	if (phb->type != PNV_PHB_NPU_NVLINK || !npe->pdev)
> -		return -EINVAL;
> -
> -	rc = pnv_npu_unset_window(npe, 0);
> -	if (rc != OPAL_SUCCESS)
> -		return rc;
> -
> -	/* Enable the bypass window */
> -
> -	top = roundup_pow_of_two(top);
> -	dev_info(&npe->pdev->dev, "Enabling bypass for PE %x\n",
> -			npe->pe_number);
> -	rc = opal_pci_map_pe_dma_window_real(phb->opal_id,
> -			npe->pe_number, npe->pe_number,
> -			0 /* bypass base */, top);
> -
> -	if (rc == OPAL_SUCCESS)
> -		pnv_pci_ioda2_tce_invalidate_entire(phb, false);
> -
> -	return rc;
> -}
> -
> -void pnv_npu_try_dma_set_bypass(struct pci_dev *gpdev, bool bypass)
> -{
> -	int i;
> -	struct pnv_phb *phb;
> -	struct pci_dn *pdn;
> -	struct pnv_ioda_pe *npe;
> -	struct pci_dev *npdev;
> -
> -	for (i = 0; ; ++i) {
> -		npdev = pnv_pci_get_npu_dev(gpdev, i);
> -
> -		if (!npdev)
> -			break;
> -
> -		pdn = pci_get_pdn(npdev);
> -		if (WARN_ON(!pdn || pdn->pe_number == IODA_INVALID_PE))
> -			return;
> -
> -		phb = pci_bus_to_host(npdev->bus)->private_data;
> -
> -		/* We only do bypass if it's enabled on the linked device */
> -		npe = &phb->ioda.pe_array[pdn->pe_number];
> -
> -		if (bypass) {
> -			dev_info(&npdev->dev,
> -					"Using 64-bit DMA iommu bypass\n");
> -			pnv_npu_dma_set_bypass(npe);
> -		} else {
> -			dev_info(&npdev->dev, "Using 32-bit DMA via iommu\n");
> -			pnv_npu_dma_set_32(npe);
> -		}
> -	}
> -}
> -
> -/* Switch ownership from platform code to external user (e.g. VFIO) */
> -void pnv_npu_take_ownership(struct pnv_ioda_pe *npe)
> -{
> -	struct pnv_phb *phb = npe->phb;
> -	int64_t rc;
> -
> -	/*
> -	 * Note: NPU has just a single TVE in the hardware which means that
> -	 * while used by the kernel, it can have either 32bit window or
> -	 * DMA bypass but never both. So we deconfigure 32bit window only
> -	 * if it was enabled at the moment of ownership change.
> -	 */
> -	if (npe->table_group.tables[0]) {
> -		pnv_npu_unset_window(npe, 0);
> -		return;
> -	}
> -
> -	/* Disable bypass */
> -	rc = opal_pci_map_pe_dma_window_real(phb->opal_id,
> -			npe->pe_number, npe->pe_number,
> -			0 /* bypass base */, 0);
> -	if (rc) {
> -		pe_err(npe, "Failed to disable bypass, err %lld\n", rc);
> -		return;
> -	}
> -	pnv_pci_ioda2_tce_invalidate_entire(npe->phb, false);
> -}
> -
> -struct pnv_ioda_pe *pnv_pci_npu_setup_iommu(struct pnv_ioda_pe *npe)
> -{
> -	struct pnv_phb *phb = npe->phb;
> -	struct pci_bus *pbus = phb->hose->bus;
> -	struct pci_dev *npdev, *gpdev = NULL, *gptmp;
> -	struct pnv_ioda_pe *gpe = get_gpu_pci_dev_and_pe(npe, &gpdev);
> -
> -	if (!gpe || !gpdev)
> -		return NULL;
> -
> -	list_for_each_entry(npdev, &pbus->devices, bus_list) {
> -		gptmp = pnv_pci_get_gpu_dev(npdev);
> -
> -		if (gptmp != gpdev)
> -			continue;
> -
> -		pe_info(gpe, "Attached NPU %s\n", dev_name(&npdev->dev));
> -		iommu_group_add_device(gpe->table_group.group, &npdev->dev);
> -	}
> -
> -	return gpe;
> -}
> -
> -/* Maximum number of nvlinks per npu */
> -#define NV_MAX_LINKS 6
> -
> -/* Maximum index of npu2 hosts in the system. Always < NV_MAX_NPUS */
> -static int max_npu2_index;
> -
> -struct npu_context {
> -	struct mm_struct *mm;
> -	struct pci_dev *npdev[NV_MAX_NPUS][NV_MAX_LINKS];
> -	struct mmu_notifier mn;
> -	struct kref kref;
> -	bool nmmu_flush;
> -
> -	/* Callback to stop translation requests on a given GPU */
> -	void (*release_cb)(struct npu_context *context, void *priv);
> -
> -	/*
> -	 * Private pointer passed to the above callback for usage by
> -	 * device drivers.
> -	 */
> -	void *priv;
> -};
> -
> -struct mmio_atsd_reg {
> -	struct npu *npu;
> -	int reg;
> -};
> -
> -/*
> - * Find a free MMIO ATSD register and mark it in use. Return -ENOSPC
> - * if none are available.
> - */
> -static int get_mmio_atsd_reg(struct npu *npu)
> -{
> -	int i;
> -
> -	for (i = 0; i < npu->mmio_atsd_count; i++) {
> -		if (!test_bit(i, &npu->mmio_atsd_usage))
> -			if (!test_and_set_bit_lock(i, &npu->mmio_atsd_usage))
> -				return i;
> -	}
> -
> -	return -ENOSPC;
> -}
> -
> -static void put_mmio_atsd_reg(struct npu *npu, int reg)
> -{
> -	clear_bit_unlock(reg, &npu->mmio_atsd_usage);
> -}
> -
> -/* MMIO ATSD register offsets */
> -#define XTS_ATSD_LAUNCH 0
> -#define XTS_ATSD_AVA    1
> -#define XTS_ATSD_STAT   2
> -
> -static unsigned long get_atsd_launch_val(unsigned long pid, unsigned long psize)
> -{
> -	unsigned long launch = 0;
> -
> -	if (psize == MMU_PAGE_COUNT) {
> -		/* IS set to invalidate entire matching PID */
> -		launch |= PPC_BIT(12);
> -	} else {
> -		/* AP set to invalidate region of psize */
> -		launch |= (u64)mmu_get_ap(psize) << PPC_BITLSHIFT(17);
> -	}
> -
> -	/* PRS set to process-scoped */
> -	launch |= PPC_BIT(13);
> -
> -	/* PID */
> -	launch |= pid << PPC_BITLSHIFT(38);
> -
> -	/* Leave "No flush" (bit 39) 0 so every ATSD performs a flush */
> -
> -	return launch;
> -}
> -
> -static void mmio_atsd_regs_write(struct mmio_atsd_reg
> -			mmio_atsd_reg[NV_MAX_NPUS], unsigned long offset,
> -			unsigned long val)
> -{
> -	struct npu *npu;
> -	int i, reg;
> -
> -	for (i = 0; i <= max_npu2_index; i++) {
> -		reg = mmio_atsd_reg[i].reg;
> -		if (reg < 0)
> -			continue;
> -
> -		npu = mmio_atsd_reg[i].npu;
> -		__raw_writeq_be(val, npu->mmio_atsd_regs[reg] + offset);
> -	}
> -}
> -
> -static void mmio_invalidate_pid(struct mmio_atsd_reg mmio_atsd_reg[NV_MAX_NPUS],
> -				unsigned long pid)
> -{
> -	unsigned long launch = get_atsd_launch_val(pid, MMU_PAGE_COUNT);
> -
> -	/* Invalidating the entire process doesn't use a va */
> -	mmio_atsd_regs_write(mmio_atsd_reg, XTS_ATSD_LAUNCH, launch);
> -}
> -
> -static void mmio_invalidate_range(struct mmio_atsd_reg
> -			mmio_atsd_reg[NV_MAX_NPUS], unsigned long pid,
> -			unsigned long start, unsigned long psize)
> -{
> -	unsigned long launch = get_atsd_launch_val(pid, psize);
> -
> -	/* Write all VAs first */
> -	mmio_atsd_regs_write(mmio_atsd_reg, XTS_ATSD_AVA, start);
> -
> -	/* Issue one barrier for all address writes */
> -	eieio();
> -
> -	/* Launch */
> -	mmio_atsd_regs_write(mmio_atsd_reg, XTS_ATSD_LAUNCH, launch);
> -}
> -
> -#define mn_to_npu_context(x) container_of(x, struct npu_context, mn)
> -
> -static void mmio_invalidate_wait(
> -	struct mmio_atsd_reg mmio_atsd_reg[NV_MAX_NPUS])
> -{
> -	struct npu *npu;
> -	int i, reg;
> -
> -	/* Wait for all invalidations to complete */
> -	for (i = 0; i <= max_npu2_index; i++) {
> -		if (mmio_atsd_reg[i].reg < 0)
> -			continue;
> -
> -		/* Wait for completion */
> -		npu = mmio_atsd_reg[i].npu;
> -		reg = mmio_atsd_reg[i].reg;
> -		while (__raw_readq(npu->mmio_atsd_regs[reg] + XTS_ATSD_STAT))
> -			cpu_relax();
> -	}
> -}
> -
> -/*
> - * Acquires all the address translation shootdown (ATSD) registers required to
> - * launch an ATSD on all links this npu_context is active on.
> - */
> -static void acquire_atsd_reg(struct npu_context *npu_context,
> -			struct mmio_atsd_reg mmio_atsd_reg[NV_MAX_NPUS])
> -{
> -	int i, j;
> -	struct npu *npu;
> -	struct pci_dev *npdev;
> -	struct pnv_phb *nphb;
> -
> -	for (i = 0; i <= max_npu2_index; i++) {
> -		mmio_atsd_reg[i].reg = -1;
> -		for (j = 0; j < NV_MAX_LINKS; j++) {
> -			/*
> -			 * There are no ordering requirements with respect to
> -			 * the setup of struct npu_context, but to ensure
> -			 * consistent behaviour we need to ensure npdev[][] is
> -			 * only read once.
> -			 */
> -			npdev = READ_ONCE(npu_context->npdev[i][j]);
> -			if (!npdev)
> -				continue;
> -
> -			nphb = pci_bus_to_host(npdev->bus)->private_data;
> -			npu = &nphb->npu;
> -			mmio_atsd_reg[i].npu = npu;
> -			mmio_atsd_reg[i].reg = get_mmio_atsd_reg(npu);
> -			while (mmio_atsd_reg[i].reg < 0) {
> -				mmio_atsd_reg[i].reg = get_mmio_atsd_reg(npu);
> -				cpu_relax();
> -			}
> -			break;
> -		}
> -	}
> -}
> -
> -/*
> - * Release previously acquired ATSD registers. To avoid deadlocks the registers
> - * must be released in the same order they were acquired above in
> - * acquire_atsd_reg.
> - */
> -static void release_atsd_reg(struct mmio_atsd_reg mmio_atsd_reg[NV_MAX_NPUS])
> -{
> -	int i;
> -
> -	for (i = 0; i <= max_npu2_index; i++) {
> -		/*
> -		 * We can't rely on npu_context->npdev[][] being the same here
> -		 * as when acquire_atsd_reg() was called, hence we use the
> -		 * values stored in mmio_atsd_reg during the acquire phase
> -		 * rather than re-reading npdev[][].
> -		 */
> -		if (mmio_atsd_reg[i].reg < 0)
> -			continue;
> -
> -		put_mmio_atsd_reg(mmio_atsd_reg[i].npu, mmio_atsd_reg[i].reg);
> -	}
> -}
> -
> -/*
> - * Invalidate a virtual address range
> - */
> -static void mmio_invalidate(struct npu_context *npu_context,
> -			unsigned long start, unsigned long size)
> -{
> -	struct mmio_atsd_reg mmio_atsd_reg[NV_MAX_NPUS];
> -	unsigned long pid = npu_context->mm->context.id;
> -	unsigned long atsd_start = 0;
> -	unsigned long end = start + size - 1;
> -	int atsd_psize = MMU_PAGE_COUNT;
> -
> -	/*
> -	 * Convert the input range into one of the supported sizes. If the range
> -	 * doesn't fit, use the next larger supported size. Invalidation latency
> -	 * is high, so over-invalidation is preferred to issuing multiple
> -	 * invalidates.
> -	 *
> -	 * A 4K page size isn't supported by NPU/GPU ATS, so that case is
> -	 * ignored.
> -	 */
> -	if (size == SZ_64K) {
> -		atsd_start = start;
> -		atsd_psize = MMU_PAGE_64K;
> -	} else if (ALIGN_DOWN(start, SZ_2M) == ALIGN_DOWN(end, SZ_2M)) {
> -		atsd_start = ALIGN_DOWN(start, SZ_2M);
> -		atsd_psize = MMU_PAGE_2M;
> -	} else if (ALIGN_DOWN(start, SZ_1G) == ALIGN_DOWN(end, SZ_1G)) {
> -		atsd_start = ALIGN_DOWN(start, SZ_1G);
> -		atsd_psize = MMU_PAGE_1G;
> -	}
> -
> -	if (npu_context->nmmu_flush)
> -		/*
> -		 * Unfortunately the nest mmu does not support flushing specific
> -		 * addresses so we have to flush the whole mm once before
> -		 * shooting down the GPU translation.
> -		 */
> -		flush_all_mm(npu_context->mm);
> -
> -	/*
> -	 * Loop over all the NPUs this process is active on and launch
> -	 * an invalidate.
> -	 */
> -	acquire_atsd_reg(npu_context, mmio_atsd_reg);
> -
> -	if (atsd_psize == MMU_PAGE_COUNT)
> -		mmio_invalidate_pid(mmio_atsd_reg, pid);
> -	else
> -		mmio_invalidate_range(mmio_atsd_reg, pid, atsd_start,
> -					atsd_psize);
> -
> -	mmio_invalidate_wait(mmio_atsd_reg);
> -
> -	/*
> -	 * The GPU requires two flush ATSDs to ensure all entries have been
> -	 * flushed. We use PID 0 as it will never be used for a process on the
> -	 * GPU.
> -	 */
> -	mmio_invalidate_pid(mmio_atsd_reg, 0);
> -	mmio_invalidate_wait(mmio_atsd_reg);
> -	mmio_invalidate_pid(mmio_atsd_reg, 0);
> -	mmio_invalidate_wait(mmio_atsd_reg);
> -
> -	release_atsd_reg(mmio_atsd_reg);
> -}
> -
> -static void pnv_npu2_mn_release(struct mmu_notifier *mn,
> -				struct mm_struct *mm)
> -{
> -	struct npu_context *npu_context = mn_to_npu_context(mn);
> -
> -	/* Call into device driver to stop requests to the NMMU */
> -	if (npu_context->release_cb)
> -		npu_context->release_cb(npu_context, npu_context->priv);
> -
> -	/*
> -	 * There should be no more translation requests for this PID, but we
> -	 * need to ensure any entries for it are removed from the TLB.
> -	 */
> -	mmio_invalidate(npu_context, 0, ~0UL);
> -}
> -
> -static void pnv_npu2_mn_change_pte(struct mmu_notifier *mn,
> -				struct mm_struct *mm,
> -				unsigned long address,
> -				pte_t pte)
> -{
> -	struct npu_context *npu_context = mn_to_npu_context(mn);
> -	mmio_invalidate(npu_context, address, PAGE_SIZE);
> -}
> -
> -static void pnv_npu2_mn_invalidate_range(struct mmu_notifier *mn,
> -					struct mm_struct *mm,
> -					unsigned long start, unsigned long end)
> -{
> -	struct npu_context *npu_context = mn_to_npu_context(mn);
> -	mmio_invalidate(npu_context, start, end - start);
> -}
> -
> -static const struct mmu_notifier_ops nv_nmmu_notifier_ops = {
> -	.release = pnv_npu2_mn_release,
> -	.change_pte = pnv_npu2_mn_change_pte,
> -	.invalidate_range = pnv_npu2_mn_invalidate_range,
> -};
> -
> -/*
> - * Call into OPAL to setup the nmmu context for the current task in
> - * the NPU. This must be called to setup the context tables before the
> - * GPU issues ATRs. pdev should be a pointed to PCIe GPU device.
> - *
> - * A release callback should be registered to allow a device driver to
> - * be notified that it should not launch any new translation requests
> - * as the final TLB invalidate is about to occur.
> - *
> - * Returns an error if there no contexts are currently available or a
> - * npu_context which should be passed to pnv_npu2_handle_fault().
> - *
> - * mmap_sem must be held in write mode and must not be called from interrupt
> - * context.
> - */
> -struct npu_context *pnv_npu2_init_context(struct pci_dev *gpdev,
> -			unsigned long flags,
> -			void (*cb)(struct npu_context *, void *),
> -			void *priv)

> -{
> -	int rc;
> -	u32 nvlink_index;
> -	struct device_node *nvlink_dn;
> -	struct mm_struct *mm = current->mm;
> -	struct pnv_phb *nphb;
> -	struct npu *npu;
> -	struct npu_context *npu_context;
> -
> -	/*
> -	 * At present we don't support GPUs connected to multiple NPUs and I'm
> -	 * not sure the hardware does either.
> -	 */
> -	struct pci_dev *npdev = pnv_pci_get_npu_dev(gpdev, 0);
> -
> -	if (!firmware_has_feature(FW_FEATURE_OPAL))
> -		return ERR_PTR(-ENODEV);
> -
> -	if (!npdev)
> -		/* No nvlink associated with this GPU device */
> -		return ERR_PTR(-ENODEV);
> -
> -	nvlink_dn = of_parse_phandle(npdev->dev.of_node, "ibm,nvlink", 0);
> -	if (WARN_ON(of_property_read_u32(nvlink_dn, "ibm,npu-link-index",
> -							&nvlink_index)))
> -		return ERR_PTR(-ENODEV);
> -
> -	if (!mm || mm->context.id == 0) {
> -		/*
> -		 * Kernel thread contexts are not supported and context id 0 is
> -		 * reserved on the GPU.
> -		 */
> -		return ERR_PTR(-EINVAL);
> -	}
> -
> -	nphb = pci_bus_to_host(npdev->bus)->private_data;
> -	npu = &nphb->npu;
> -
> -	/*
> -	 * Setup the NPU context table for a particular GPU. These need to be
> -	 * per-GPU as we need the tables to filter ATSDs when there are no
> -	 * active contexts on a particular GPU. It is safe for these to be
> -	 * called concurrently with destroy as the OPAL call takes appropriate
> -	 * locks and refcounts on init/destroy.
> -	 */
> -	rc = opal_npu_init_context(nphb->opal_id, mm->context.id, flags,
> -				PCI_DEVID(gpdev->bus->number, gpdev->devfn));
> -	if (rc < 0)
> -		return ERR_PTR(-ENOSPC);
> -
> -	/*
> -	 * We store the npu pci device so we can more easily get at the
> -	 * associated npus.
> -	 */
> -	spin_lock(&npu_context_lock);
> -	npu_context = mm->context.npu_context;
> -	if (npu_context) {
> -		if (npu_context->release_cb != cb ||
> -			npu_context->priv != priv) {
> -			spin_unlock(&npu_context_lock);
> -			opal_npu_destroy_context(nphb->opal_id, mm->context.id,
> -						PCI_DEVID(gpdev->bus->number,
> -							gpdev->devfn));
> -			return ERR_PTR(-EINVAL);
> -		}
> -
> -		WARN_ON(!kref_get_unless_zero(&npu_context->kref));
> -	}
> -	spin_unlock(&npu_context_lock);
> -
> -	if (!npu_context) {
> -		/*
> -		 * We can set up these fields without holding the
> -		 * npu_context_lock as the npu_context hasn't been returned to
> -		 * the caller meaning it can't be destroyed. Parallel allocation
> -		 * is protected against by mmap_sem.
> -		 */
> -		rc = -ENOMEM;
> -		npu_context = kzalloc(sizeof(struct npu_context), GFP_KERNEL);
> -		if (npu_context) {
> -			kref_init(&npu_context->kref);
> -			npu_context->mm = mm;
> -			npu_context->mn.ops = &nv_nmmu_notifier_ops;
> -			rc = __mmu_notifier_register(&npu_context->mn, mm);
> -		}
> -
> -		if (rc) {
> -			kfree(npu_context);
> -			opal_npu_destroy_context(nphb->opal_id, mm->context.id,
> -					PCI_DEVID(gpdev->bus->number,
> -						gpdev->devfn));
> -			return ERR_PTR(rc);
> -		}
> -
> -		mm->context.npu_context = npu_context;
> -	}
> -
> -	npu_context->release_cb = cb;
> -	npu_context->priv = priv;
> -
> -	/*
> -	 * npdev is a pci_dev pointer setup by the PCI code. We assign it to
> -	 * npdev[][] to indicate to the mmu notifiers that an invalidation
> -	 * should also be sent over this nvlink. The notifiers don't use any
> -	 * other fields in npu_context, so we just need to ensure that when they
> -	 * deference npu_context->npdev[][] it is either a valid pointer or
> -	 * NULL.
> -	 */
> -	WRITE_ONCE(npu_context->npdev[npu->index][nvlink_index], npdev);
> -
> -	if (!nphb->npu.nmmu_flush) {
> -		/*
> -		 * If we're not explicitly flushing ourselves we need to mark
> -		 * the thread for global flushes
> -		 */
> -		npu_context->nmmu_flush = false;
> -		mm_context_add_copro(mm);
> -	} else
> -		npu_context->nmmu_flush = true;
> -
> -	return npu_context;
> -}
> -EXPORT_SYMBOL(pnv_npu2_init_context);
> -
> -static void pnv_npu2_release_context(struct kref *kref)
> -{
> -	struct npu_context *npu_context =
> -		container_of(kref, struct npu_context, kref);
> -
> -	if (!npu_context->nmmu_flush)
> -		mm_context_remove_copro(npu_context->mm);
> -
> -	npu_context->mm->context.npu_context = NULL;
> -}
> -
> -/*
> - * Destroy a context on the given GPU. May free the npu_context if it is no
> - * longer active on any GPUs. Must not be called from interrupt context.
> - */
> -void pnv_npu2_destroy_context(struct npu_context *npu_context,
> -			struct pci_dev *gpdev)
> -{
> -	int removed;
> -	struct pnv_phb *nphb;
> -	struct npu *npu;
> -	struct pci_dev *npdev = pnv_pci_get_npu_dev(gpdev, 0);
> -	struct device_node *nvlink_dn;
> -	u32 nvlink_index;
> -
> -	if (WARN_ON(!npdev))
> -		return;
> -
> -	if (!firmware_has_feature(FW_FEATURE_OPAL))
> -		return;
> -
> -	nphb = pci_bus_to_host(npdev->bus)->private_data;
> -	npu = &nphb->npu;
> -	nvlink_dn = of_parse_phandle(npdev->dev.of_node, "ibm,nvlink", 0);
> -	if (WARN_ON(of_property_read_u32(nvlink_dn, "ibm,npu-link-index",
> -							&nvlink_index)))
> -		return;
> -	WRITE_ONCE(npu_context->npdev[npu->index][nvlink_index], NULL);
> -	opal_npu_destroy_context(nphb->opal_id, npu_context->mm->context.id,
> -				PCI_DEVID(gpdev->bus->number, gpdev->devfn));
> -	spin_lock(&npu_context_lock);
> -	removed = kref_put(&npu_context->kref, pnv_npu2_release_context);
> -	spin_unlock(&npu_context_lock);
> -
> -	/*
> -	 * We need to do this outside of pnv_npu2_release_context so that it is
> -	 * outside the spinlock as mmu_notifier_destroy uses SRCU.
> -	 */
> -	if (removed) {
> -		mmu_notifier_unregister(&npu_context->mn,
> -					npu_context->mm);
> -
> -		kfree(npu_context);
> -	}
> -
> -}
> -EXPORT_SYMBOL(pnv_npu2_destroy_context);
> -
> -/*
> - * Assumes mmap_sem is held for the contexts associated mm.
> - */
> -int pnv_npu2_handle_fault(struct npu_context *context, uintptr_t *ea,
> -			unsigned long *flags, unsigned long *status, int count)
> -{
> -	u64 rc = 0, result = 0;
> -	int i, is_write;
> -	struct page *page[1];
> -
> -	/* mmap_sem should be held so the struct_mm must be present */
> -	struct mm_struct *mm = context->mm;
> -
> -	if (!firmware_has_feature(FW_FEATURE_OPAL))
> -		return -ENODEV;
> -
> -	WARN_ON(!rwsem_is_locked(&mm->mmap_sem));
> -
> -	for (i = 0; i < count; i++) {
> -		is_write = flags[i] & NPU2_WRITE;
> -		rc = get_user_pages_remote(NULL, mm, ea[i], 1,
> -					is_write ? FOLL_WRITE : 0,
> -					page, NULL, NULL);
> -
> -		/*
> -		 * To support virtualised environments we will have to do an
> -		 * access to the page to ensure it gets faulted into the
> -		 * hypervisor. For the moment virtualisation is not supported in
> -		 * other areas so leave the access out.
> -		 */
> -		if (rc != 1) {
> -			status[i] = rc;
> -			result = -EFAULT;
> -			continue;
> -		}
> -
> -		status[i] = 0;
> -		put_page(page[0]);
> -	}
> -
> -	return result;
> -}
> -EXPORT_SYMBOL(pnv_npu2_handle_fault);
> -
> -int pnv_npu2_init(struct pnv_phb *phb)
> -{
> -	unsigned int i;
> -	u64 mmio_atsd;
> -	struct device_node *dn;
> -	struct pci_dev *gpdev;
> -	static int npu_index;
> -	uint64_t rc = 0;
> -
> -	phb->npu.nmmu_flush =
> -		of_property_read_bool(phb->hose->dn, "ibm,nmmu-flush");
> -	for_each_child_of_node(phb->hose->dn, dn) {
> -		gpdev = pnv_pci_get_gpu_dev(get_pci_dev(dn));
> -		if (gpdev) {
> -			rc = opal_npu_map_lpar(phb->opal_id,
> -				PCI_DEVID(gpdev->bus->number, gpdev->devfn),
> -				0, 0);

I heavily hacked on these (draft):
https://patchwork.ozlabs.org/project/kvm-ppc/list/?series=70791

and the result is going to be used for VFIO purposes (draft too):
https://patchwork.ozlabs.org/project/kvm-ppc/list/?series=70793

Other bits can go away from npu-dma but I still need some to make
KVM+VFIO work for GPUs, this is without any vendor driver on the host
side whatsoever.


> -			if (rc)
> -				dev_err(&gpdev->dev,
> -					"Error %lld mapping device to LPAR\n",
> -					rc);
> -		}
> -	}
> -
> -	for (i = 0; !of_property_read_u64_index(phb->hose->dn, "ibm,mmio-atsd",
> -							i, &mmio_atsd); i++)
> -		phb->npu.mmio_atsd_regs[i] = ioremap(mmio_atsd, 32);
> -
> -	pr_info("NPU%lld: Found %d MMIO ATSD registers", phb->opal_id, i);
> -	phb->npu.mmio_atsd_count = i;
> -	phb->npu.mmio_atsd_usage = 0;
> -	npu_index++;
> -	if (WARN_ON(npu_index >= NV_MAX_NPUS))
> -		return -ENOSPC;
> -	max_npu2_index = npu_index;
> -	phb->npu.index = npu_index;
> -
> -	return 0;
> -}
> diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c
> index cde710297a4e..f480e3fc9ebb 100644
> --- a/arch/powerpc/platforms/powernv/pci-ioda.c
> +++ b/arch/powerpc/platforms/powernv/pci-ioda.c
> @@ -1203,75 +1203,6 @@ static struct pnv_ioda_pe *pnv_ioda_setup_bus_PE(struct pci_bus *bus, bool all)
>  	return pe;
>  }
>  
> -static struct pnv_ioda_pe *pnv_ioda_setup_npu_PE(struct pci_dev *npu_pdev)
> -{
> -	int pe_num, found_pe = false, rc;
> -	long rid;
> -	struct pnv_ioda_pe *pe;
> -	struct pci_dev *gpu_pdev;
> -	struct pci_dn *npu_pdn;
> -	struct pci_controller *hose = pci_bus_to_host(npu_pdev->bus);
> -	struct pnv_phb *phb = hose->private_data;
> -
> -	/*
> -	 * Due to a hardware errata PE#0 on the NPU is reserved for
> -	 * error handling. This means we only have three PEs remaining
> -	 * which need to be assigned to four links, implying some
> -	 * links must share PEs.
> -	 *
> -	 * To achieve this we assign PEs such that NPUs linking the
> -	 * same GPU get assigned the same PE.
> -	 */
> -	gpu_pdev = pnv_pci_get_gpu_dev(npu_pdev);
> -	for (pe_num = 0; pe_num < phb->ioda.total_pe_num; pe_num++) {
> -		pe = &phb->ioda.pe_array[pe_num];
> -		if (!pe->pdev)
> -			continue;
> -
> -		if (pnv_pci_get_gpu_dev(pe->pdev) == gpu_pdev) {
> -			/*
> -			 * This device has the same peer GPU so should
> -			 * be assigned the same PE as the existing
> -			 * peer NPU.
> -			 */
> -			dev_info(&npu_pdev->dev,
> -				"Associating to existing PE %x\n", pe_num);
> -			pci_dev_get(npu_pdev);
> -			npu_pdn = pci_get_pdn(npu_pdev);
> -			rid = npu_pdev->bus->number << 8 | npu_pdn->devfn;
> -			npu_pdn->pe_number = pe_num;
> -			phb->ioda.pe_rmap[rid] = pe->pe_number;
> -
> -			/* Map the PE to this link */
> -			rc = opal_pci_set_pe(phb->opal_id, pe_num, rid,
> -					OpalPciBusAll,
> -					OPAL_COMPARE_RID_DEVICE_NUMBER,
> -					OPAL_COMPARE_RID_FUNCTION_NUMBER,
> -					OPAL_MAP_PE);
> -			WARN_ON(rc != OPAL_SUCCESS);
> -			found_pe = true;
> -			break;
> -		}
> -	}
> -
> -	if (!found_pe)
> -		/*
> -		 * Could not find an existing PE so allocate a new
> -		 * one.
> -		 */
> -		return pnv_ioda_setup_dev_PE(npu_pdev);
> -	else
> -		return pe;
> -}
> -
> -static void pnv_ioda_setup_npu_PEs(struct pci_bus *bus)
> -{
> -	struct pci_dev *pdev;
> -
> -	list_for_each_entry(pdev, &bus->devices, bus_list)
> -		pnv_ioda_setup_npu_PE(pdev);
> -}
> -
>  static void pnv_pci_ioda_setup_PEs(void)
>  {
>  	struct pci_controller *hose, *tmp;
> @@ -1281,13 +1212,6 @@ static void pnv_pci_ioda_setup_PEs(void)
>  
>  	list_for_each_entry_safe(hose, tmp, &hose_list, list_node) {
>  		phb = hose->private_data;
> -		if (phb->type == PNV_PHB_NPU_NVLINK) {
> -			/* PE#0 is needed for error reporting */
> -			pnv_ioda_reserve_pe(phb, 0);
> -			pnv_ioda_setup_npu_PEs(hose->bus);
> -			if (phb->model == PNV_PHB_MODEL_NPU2)
> -				pnv_npu2_init(phb);
> -		}
>  		if (phb->type == PNV_PHB_NPU_OCAPI) {
>  			bus = hose->bus;
>  			list_for_each_entry(pdev, &bus->devices, bus_list)
> @@ -1895,9 +1819,6 @@ static int pnv_pci_ioda_dma_set_mask(struct pci_dev *pdev, u64 dma_mask)
>  	}
>  	*pdev->dev.dma_mask = dma_mask;
>  
> -	/* Update peer npu devices */
> -	pnv_npu_try_dma_set_bypass(pdev, bypass);
> -
>  	return 0;
>  }
>  
> @@ -2143,14 +2064,6 @@ static void pnv_pci_ioda2_tce_invalidate(struct iommu_table *tbl,
>  	}
>  }
>  
> -void pnv_pci_ioda2_tce_invalidate_entire(struct pnv_phb *phb, bool rm)
> -{
> -	if (phb->model == PNV_PHB_MODEL_NPU || phb->model == PNV_PHB_MODEL_PHB3)
> -		pnv_pci_phb3_tce_invalidate_entire(phb, rm);
> -	else
> -		opal_pci_tce_kill(phb->opal_id, OPAL_PCI_TCE_KILL, 0, 0, 0, 0);
> -}
> -
>  static int pnv_ioda2_tce_build(struct iommu_table *tbl, long index,
>  		long npages, unsigned long uaddr,
>  		enum dma_data_direction direction,
> @@ -2639,137 +2552,6 @@ static struct iommu_table_group_ops pnv_pci_ioda2_ops = {
>  	.take_ownership = pnv_ioda2_take_ownership,
>  	.release_ownership = pnv_ioda2_release_ownership,
>  };
> -
> -static int gpe_table_group_to_npe_cb(struct device *dev, void *opaque)
> -{
> -	struct pci_controller *hose;
> -	struct pnv_phb *phb;
> -	struct pnv_ioda_pe **ptmppe = opaque;
> -	struct pci_dev *pdev = container_of(dev, struct pci_dev, dev);
> -	struct pci_dn *pdn = pci_get_pdn(pdev);
> -
> -	if (!pdn || pdn->pe_number == IODA_INVALID_PE)
> -		return 0;
> -
> -	hose = pci_bus_to_host(pdev->bus);
> -	phb = hose->private_data;
> -	if (phb->type != PNV_PHB_NPU_NVLINK)
> -		return 0;
> -
> -	*ptmppe = &phb->ioda.pe_array[pdn->pe_number];
> -
> -	return 1;
> -}
> -
> -/*
> - * This returns PE of associated NPU.
> - * This assumes that NPU is in the same IOMMU group with GPU and there is
> - * no other PEs.
> - */
> -static struct pnv_ioda_pe *gpe_table_group_to_npe(
> -		struct iommu_table_group *table_group)
> -{
> -	struct pnv_ioda_pe *npe = NULL;
> -	int ret = iommu_group_for_each_dev(table_group->group, &npe,
> -			gpe_table_group_to_npe_cb);
> -
> -	BUG_ON(!ret || !npe);
> -
> -	return npe;
> -}
> -
> -static long pnv_pci_ioda2_npu_set_window(struct iommu_table_group *table_group,
> -		int num, struct iommu_table *tbl)
> -{
> -	struct pnv_ioda_pe *npe = gpe_table_group_to_npe(table_group);
> -	int num2 = (num == 0) ? 1 : 0;
> -	long ret = pnv_pci_ioda2_set_window(table_group, num, tbl);
> -
> -	if (ret)
> -		return ret;
> -
> -	if (table_group->tables[num2])
> -		pnv_npu_unset_window(npe, num2);
> -
> -	ret = pnv_npu_set_window(npe, num, tbl);
> -	if (ret) {
> -		pnv_pci_ioda2_unset_window(table_group, num);
> -		if (table_group->tables[num2])
> -			pnv_npu_set_window(npe, num2,
> -					table_group->tables[num2]);
> -	}
> -
> -	return ret;
> -}
> -
> -static long pnv_pci_ioda2_npu_unset_window(
> -		struct iommu_table_group *table_group,
> -		int num)
> -{
> -	struct pnv_ioda_pe *npe = gpe_table_group_to_npe(table_group);
> -	int num2 = (num == 0) ? 1 : 0;
> -	long ret = pnv_pci_ioda2_unset_window(table_group, num);
> -
> -	if (ret)
> -		return ret;
> -
> -	if (!npe->table_group.tables[num])
> -		return 0;
> -
> -	ret = pnv_npu_unset_window(npe, num);
> -	if (ret)
> -		return ret;
> -
> -	if (table_group->tables[num2])
> -		ret = pnv_npu_set_window(npe, num2, table_group->tables[num2]);
> -
> -	return ret;
> -}
> -
> -static void pnv_ioda2_npu_take_ownership(struct iommu_table_group *table_group)
> -{
> -	/*
> -	 * Detach NPU first as pnv_ioda2_take_ownership() will destroy
> -	 * the iommu_table if 32bit DMA is enabled.
> -	 */
> -	pnv_npu_take_ownership(gpe_table_group_to_npe(table_group));
> -	pnv_ioda2_take_ownership(table_group);
> -}
> -
> -static struct iommu_table_group_ops pnv_pci_ioda2_npu_ops = {
> -	.get_table_size = pnv_pci_ioda2_get_table_size,
> -	.create_table = pnv_pci_ioda2_create_table_userspace,
> -	.set_window = pnv_pci_ioda2_npu_set_window,
> -	.unset_window = pnv_pci_ioda2_npu_unset_window,
> -	.take_ownership = pnv_ioda2_npu_take_ownership,
> -	.release_ownership = pnv_ioda2_release_ownership,


These are called from the VFIO SPAPR TCE IOMMU subdriver when certain
GPUs are passed through with VFIO:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/vfio/vfio_iommu_spapr_tce.c


> -};
> -
> -static void pnv_pci_ioda_setup_iommu_api(void)
> -{
> -	struct pci_controller *hose, *tmp;
> -	struct pnv_phb *phb;
> -	struct pnv_ioda_pe *pe, *gpe;
> -
> -	/*
> -	 * Now we have all PHBs discovered, time to add NPU devices to
> -	 * the corresponding IOMMU groups.
> -	 */
> -	list_for_each_entry_safe(hose, tmp, &hose_list, list_node) {
> -		phb = hose->private_data;
> -
> -		if (phb->type != PNV_PHB_NPU_NVLINK)
> -			continue;
> -
> -		list_for_each_entry(pe, &phb->ioda.pe_list, list) {
> -			gpe = pnv_pci_npu_setup_iommu(pe);
> -			if (gpe)
> -				gpe->table_group.ops = &pnv_pci_ioda2_npu_ops;
> -		}
> -	}
> -}
> -#else /* !CONFIG_IOMMU_API */
> -static void pnv_pci_ioda_setup_iommu_api(void) { };
>  #endif
>  
>  static unsigned long pnv_ioda_parse_tce_sizes(struct pnv_phb *phb)
> @@ -3266,7 +3048,6 @@ static void pnv_pci_enable_bridges(void)
>  static void pnv_pci_ioda_fixup(void)
>  {
>  	pnv_pci_ioda_setup_PEs();
> -	pnv_pci_ioda_setup_iommu_api();
>  	pnv_pci_ioda_create_dbgfs();
>  
>  	pnv_pci_enable_bridges();
> @@ -3713,27 +3494,6 @@ static const struct pci_controller_ops pnv_pci_ioda_controller_ops = {
>  	.shutdown		= pnv_pci_ioda_shutdown,
>  };
>  
> -static int pnv_npu_dma_set_mask(struct pci_dev *npdev, u64 dma_mask)
> -{
> -	dev_err_once(&npdev->dev,
> -			"%s operation unsupported for NVLink devices\n",
> -			__func__);
> -	return -EPERM;
> -}
> -
> -static const struct pci_controller_ops pnv_npu_ioda_controller_ops = {
> -	.dma_dev_setup		= pnv_pci_dma_dev_setup,
> -#ifdef CONFIG_PCI_MSI
> -	.setup_msi_irqs		= pnv_setup_msi_irqs,
> -	.teardown_msi_irqs	= pnv_teardown_msi_irqs,
> -#endif
> -	.enable_device_hook	= pnv_pci_enable_device_hook,
> -	.window_alignment	= pnv_pci_window_alignment,
> -	.reset_secondary_bus	= pnv_pci_reset_secondary_bus,
> -	.dma_set_mask		= pnv_npu_dma_set_mask,
> -	.shutdown		= pnv_pci_ioda_shutdown,
> -};
> -
>  static const struct pci_controller_ops pnv_npu_ocapi_ioda_controller_ops = {
>  	.enable_device_hook	= pnv_pci_enable_device_hook,
>  	.window_alignment	= pnv_pci_window_alignment,
> @@ -3955,9 +3715,6 @@ static void __init pnv_pci_init_ioda_phb(struct device_node *np,
>  	ppc_md.pcibios_fixup = pnv_pci_ioda_fixup;
>  
>  	switch (phb->type) {
> -	case PNV_PHB_NPU_NVLINK:
> -		hose->controller_ops = pnv_npu_ioda_controller_ops;
> -		break;
>  	case PNV_PHB_NPU_OCAPI:
>  		hose->controller_ops = pnv_npu_ocapi_ioda_controller_ops;
>  		break;
> diff --git a/arch/powerpc/platforms/powernv/pci.h b/arch/powerpc/platforms/powernv/pci.h
> index 8b37b28e3831..54f2935b7ac5 100644
> --- a/arch/powerpc/platforms/powernv/pci.h
> +++ b/arch/powerpc/platforms/powernv/pci.h
> @@ -231,17 +231,6 @@ extern void pe_level_printk(const struct pnv_ioda_pe *pe, const char *level,
>  #define pe_info(pe, fmt, ...)					\
>  	pe_level_printk(pe, KERN_INFO, fmt, ##__VA_ARGS__)
>  
> -/* Nvlink functions */
> -extern void pnv_npu_try_dma_set_bypass(struct pci_dev *gpdev, bool bypass);
> -extern void pnv_pci_ioda2_tce_invalidate_entire(struct pnv_phb *phb, bool rm);
> -extern struct pnv_ioda_pe *pnv_pci_npu_setup_iommu(struct pnv_ioda_pe *npe);
> -extern long pnv_npu_set_window(struct pnv_ioda_pe *npe, int num,
> -		struct iommu_table *tbl);
> -extern long pnv_npu_unset_window(struct pnv_ioda_pe *npe, int num);
> -extern void pnv_npu_take_ownership(struct pnv_ioda_pe *npe);
> -extern void pnv_npu_release_ownership(struct pnv_ioda_pe *npe);
> -extern int pnv_npu2_init(struct pnv_phb *phb);
> -
>  /* pci-ioda-tce.c */
>  #define POWERNV_IOMMU_DEFAULT_LEVELS	1
>  #define POWERNV_IOMMU_MAX_LEVELS	5
> 


-- 
Alexey