arch/powerpc/platforms/powernv/npu-dma.c - kernel/quantenna - Git at Google

 /*
  * 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/export.h>
 #include <linux/pci.h>
 #include <linux/memblock.h>
 #include <linux/iommu.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"

 /*
  * Other types of TCE cache invalidation are not functional in the
  * hardware.
  */
 static struct pci_dev *get_pci_dev(struct device_node *dn)
 {
 	return PCI_DN(dn)->pcidev;
 }

 /* 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;

 	/* 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;

 	/* 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,
 			   struct dma_attrs *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,
 			 struct dma_attrs *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,
 				   struct dma_attrs *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,
 			  struct dma_attrs *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;
 }

 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 || !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 %d\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;
 }
	/*
	* 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/export.h>
	#include <linux/pci.h>
	#include <linux/memblock.h>
	#include <linux/iommu.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"

	/*
	* Other types of TCE cache invalidation are not functional in the
	* hardware.
	*/
	static struct pci_dev get_pci_dev(struct device_node dn)
	{
	return PCI_DN(dn)->pcidev;
	}

	/* 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;

	/* 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;

	/* 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,
	struct dma_attrs *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,
	struct dma_attrs *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,
	struct dma_attrs *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,
	struct dma_attrs *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;
	}

	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 \|\| !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 %d\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;
	}