// SPDX-License-Identifier: GPL-2.0-only
/*
 * 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.
 */

#include <linux/mmu_notifier.h>
#include <linux/mmu_context.h>
#include <linux/of.h>
#include <linux/pci.h>
#include <linux/memblock.h>
#include <linux/sizes.h>

#include <asm/debugfs.h>
#include <asm/powernv.h>
#include <asm/ppc-pci.h>
#include <asm/opal.h>

#include "pci.h"

static struct pci_dev *get_pci_dev(struct device_node *dn)
{
        struct pci_dn *pdn = PCI_DN(dn);
        struct pci_dev *pdev;

        pdev = pci_get_domain_bus_and_slot(pci_domain_nr(pdn->phb->bus),
                                           pdn->busno, pdn->devfn);

        /*
         * pci_get_domain_bus_and_slot() increased the reference count of
         * the PCI device, but callers don't need that actually as the PE
         * already holds a reference to the device. Since callers aren't
         * aware of the reference count change, call pci_dev_put() now to
         * avoid leaks.
         */
        if (pdev)
                pci_dev_put(pdev);

        return pdev;
}

/* 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);

#ifdef CONFIG_IOMMU_API
/*
 * 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;
}

static long pnv_npu_unset_window(struct iommu_table_group *table_group,
                int num);

static long pnv_npu_set_window(struct iommu_table_group *table_group, int num,
                struct iommu_table *tbl)
{
        struct pnv_ioda_pe *npe = container_of(table_group, struct pnv_ioda_pe,
                        table_group);
        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;
        int num2 = (num == 0) ? 1 : 0;

        /* NPU has just one TVE so if there is another table, remove it first */
        if (npe->table_group.tables[num2])
                pnv_npu_unset_window(&npe->table_group, num2);

        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;
}

static long pnv_npu_unset_window(struct iommu_table_group *table_group, int num)
{
        struct pnv_ioda_pe *npe = container_of(table_group, struct pnv_ioda_pe,
                        table_group);
        struct pnv_phb *phb = npe->phb;
        int64_t rc;

        if (!npe->table_group.tables[num])
                return 0;

        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;
}

/* Switch ownership from platform code to external user (e.g. VFIO) */
static void pnv_npu_take_ownership(struct iommu_table_group *table_group)
{
        struct pnv_ioda_pe *npe = container_of(table_group, struct pnv_ioda_pe,
                        table_group);
        struct pnv_phb *phb = npe->phb;
        int64_t rc;
        struct pci_dev *gpdev = NULL;

        /*
         * 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->table_group, 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);

        get_gpu_pci_dev_and_pe(npe, &gpdev);
        if (gpdev)
                pnv_npu2_unmap_lpar_dev(gpdev);
}

static void pnv_npu_release_ownership(struct iommu_table_group *table_group)
{
        struct pnv_ioda_pe *npe = container_of(table_group, struct pnv_ioda_pe,
                        table_group);
        struct pci_dev *gpdev = NULL;

        get_gpu_pci_dev_and_pe(npe, &gpdev);
        if (gpdev)
                pnv_npu2_map_lpar_dev(gpdev, 0, MSR_DR | MSR_PR | MSR_HV);
}

static struct iommu_table_group_ops pnv_pci_npu_ops = {
        .set_window = pnv_npu_set_window,
        .unset_window = pnv_npu_unset_window,
        .take_ownership = pnv_npu_take_ownership,
        .release_ownership = pnv_npu_release_ownership,
};
#endif /* !CONFIG_IOMMU_API */

/*
 * NPU2 ATS
 */
/* Maximum possible number of ATSD MMIO registers per NPU */
#define NV_NMMU_ATSD_REGS 8
#define NV_NPU_MAX_PE_NUM       16

/*
 * A compound NPU IOMMU group which might consist of 1 GPU + 2xNPUs (POWER8) or
 * up to 3 x (GPU + 2xNPUs) (POWER9).
 */
struct npu_comp {
        struct iommu_table_group table_group;
        int pe_num;
        struct pnv_ioda_pe *pe[NV_NPU_MAX_PE_NUM];
};

/* An NPU descriptor, valid for POWER9 only */
struct npu {
        int index;
        struct npu_comp npucomp;
};

#ifdef CONFIG_IOMMU_API
static long pnv_npu_peers_create_table_userspace(
                struct iommu_table_group *table_group,
                int num, __u32 page_shift, __u64 window_size, __u32 levels,
                struct iommu_table **ptbl)
{
        struct npu_comp *npucomp = container_of(table_group, struct npu_comp,
                        table_group);

        if (!npucomp->pe_num || !npucomp->pe[0] ||
                        !npucomp->pe[0]->table_group.ops ||
                        !npucomp->pe[0]->table_group.ops->create_table)
                return -EFAULT;

        return npucomp->pe[0]->table_group.ops->create_table(
                        &npucomp->pe[0]->table_group, num, page_shift,
                        window_size, levels, ptbl);
}

static long pnv_npu_peers_set_window(struct iommu_table_group *table_group,
                int num, struct iommu_table *tbl)
{
        int i, j;
        long ret = 0;
        struct npu_comp *npucomp = container_of(table_group, struct npu_comp,
                        table_group);

        for (i = 0; i < npucomp->pe_num; ++i) {
                struct pnv_ioda_pe *pe = npucomp->pe[i];

                if (!pe->table_group.ops->set_window)
                        continue;

                ret = pe->table_group.ops->set_window(&pe->table_group,
                                num, tbl);
                if (ret)
                        break;
        }

        if (ret) {
                for (j = 0; j < i; ++j) {
                        struct pnv_ioda_pe *pe = npucomp->pe[j];

                        if (!pe->table_group.ops->unset_window)
                                continue;

                        ret = pe->table_group.ops->unset_window(
                                        &pe->table_group, num);
                        if (ret)
                                break;
                }
        } else {
                table_group->tables[num] = iommu_tce_table_get(tbl);
        }

        return ret;
}

static long pnv_npu_peers_unset_window(struct iommu_table_group *table_group,
                int num)
{
        int i, j;
        long ret = 0;
        struct npu_comp *npucomp = container_of(table_group, struct npu_comp,
                        table_group);

        for (i = 0; i < npucomp->pe_num; ++i) {
                struct pnv_ioda_pe *pe = npucomp->pe[i];

                WARN_ON(npucomp->table_group.tables[num] !=
                                table_group->tables[num]);
                if (!npucomp->table_group.tables[num])
                        continue;

                if (!pe->table_group.ops->unset_window)
                        continue;

                ret = pe->table_group.ops->unset_window(&pe->table_group, num);
                if (ret)
                        break;
        }

        if (ret) {
                for (j = 0; j < i; ++j) {
                        struct pnv_ioda_pe *pe = npucomp->pe[j];

                        if (!npucomp->table_group.tables[num])
                                continue;

                        if (!pe->table_group.ops->set_window)
                                continue;

                        ret = pe->table_group.ops->set_window(&pe->table_group,
                                        num, table_group->tables[num]);
                        if (ret)
                                break;
                }
        } else if (table_group->tables[num]) {
                iommu_tce_table_put(table_group->tables[num]);
                table_group->tables[num] = NULL;
        }

        return ret;
}

static void pnv_npu_peers_take_ownership(struct iommu_table_group *table_group)
{
        int i;
        struct npu_comp *npucomp = container_of(table_group, struct npu_comp,
                        table_group);

        for (i = 0; i < npucomp->pe_num; ++i) {
                struct pnv_ioda_pe *pe = npucomp->pe[i];

                if (!pe->table_group.ops->take_ownership)
                        continue;
                pe->table_group.ops->take_ownership(&pe->table_group);
        }
}

static void pnv_npu_peers_release_ownership(
                struct iommu_table_group *table_group)
{
        int i;
        struct npu_comp *npucomp = container_of(table_group, struct npu_comp,
                        table_group);

        for (i = 0; i < npucomp->pe_num; ++i) {
                struct pnv_ioda_pe *pe = npucomp->pe[i];

                if (!pe->table_group.ops->release_ownership)
                        continue;
                pe->table_group.ops->release_ownership(&pe->table_group);
        }
}

static struct iommu_table_group_ops pnv_npu_peers_ops = {
        .get_table_size = pnv_pci_ioda2_get_table_size,
        .create_table = pnv_npu_peers_create_table_userspace,
        .set_window = pnv_npu_peers_set_window,
        .unset_window = pnv_npu_peers_unset_window,
        .take_ownership = pnv_npu_peers_take_ownership,
        .release_ownership = pnv_npu_peers_release_ownership,
};

static void pnv_comp_attach_table_group(struct npu_comp *npucomp,
                struct pnv_ioda_pe *pe)
{
        if (WARN_ON(npucomp->pe_num == NV_NPU_MAX_PE_NUM))
                return;

        npucomp->pe[npucomp->pe_num] = pe;
        ++npucomp->pe_num;
}

static struct iommu_table_group *
        pnv_try_setup_npu_table_group(struct pnv_ioda_pe *pe)
{
        struct iommu_table_group *compound_group;
        struct npu_comp *npucomp;
        struct pci_dev *gpdev = NULL;
        struct pci_controller *hose;
        struct pci_dev *npdev = NULL;

        list_for_each_entry(gpdev, &pe->pbus->devices, bus_list) {
                npdev = pnv_pci_get_npu_dev(gpdev, 0);
                if (npdev)
                        break;
        }

        if (!npdev)
                /* It is not an NPU attached device, skip */
                return NULL;

        hose = pci_bus_to_host(npdev->bus);

        if (hose->npu) {
                /* P9 case: compound group is per-NPU (all gpus, all links) */
                npucomp = &hose->npu->npucomp;
        } else {
                /* P8 case: Compound group is per-GPU (1 gpu, 2 links) */
                npucomp = pe->npucomp = kzalloc(sizeof(*npucomp), GFP_KERNEL);
        }

        compound_group = &npucomp->table_group;
        if (!compound_group->group) {
                compound_group->ops = &pnv_npu_peers_ops;
                iommu_register_group(compound_group, hose->global_number,
                                pe->pe_number);

                /* Steal capabilities from a GPU PE */
                compound_group->max_dynamic_windows_supported =
                        pe->table_group.max_dynamic_windows_supported;
                compound_group->tce32_start = pe->table_group.tce32_start;
                compound_group->tce32_size = pe->table_group.tce32_size;
                compound_group->max_levels = pe->table_group.max_levels;
                if (!compound_group->pgsizes)
                        compound_group->pgsizes = pe->table_group.pgsizes;
        }

        /*
         * The gpu would have been added to the iommu group that's created
         * for the PE. Pull it out now.
         */
        iommu_del_device(&gpdev->dev);

       /*
        * I'm not sure this is strictly required, but it's probably a good idea
        * since the table_group for the PE is going to be attached to the
        * compound table group. If we leave the PE's iommu group active then
        * we might have the same table_group being modifiable via two sepeate
        * iommu groups.
        */
        iommu_group_put(pe->table_group.group);

        /* now put the GPU into the compound group */
        pnv_comp_attach_table_group(npucomp, pe);
        iommu_add_device(compound_group, &gpdev->dev);

        return compound_group;
}

static struct iommu_table_group *pnv_npu_compound_attach(struct pnv_ioda_pe *pe)
{
        struct iommu_table_group *table_group;
        struct npu_comp *npucomp;
        struct pci_dev *gpdev = NULL;
        struct pci_dev *npdev;
        struct pnv_ioda_pe *gpe = get_gpu_pci_dev_and_pe(pe, &gpdev);

        WARN_ON(!(pe->flags & PNV_IODA_PE_DEV));
        if (!gpe)
                return NULL;

        /*
         * IODA2 bridges get this set up from pci_controller_ops::setup_bridge
         * but NPU bridges do not have this hook defined so we do it here.
         * We do not setup other table group parameters as they won't be used
         * anyway - NVLink bridges are subordinate PEs.
         */
        pe->table_group.ops = &pnv_pci_npu_ops;

        table_group = iommu_group_get_iommudata(
                        iommu_group_get(&gpdev->dev));

        /*
         * On P9 NPU PHB and PCI PHB support different page sizes,
         * keep only matching. We expect here that NVLink bridge PE pgsizes is
         * initialized by the caller.
         */
        table_group->pgsizes &= pe->table_group.pgsizes;
        npucomp = container_of(table_group, struct npu_comp, table_group);
        pnv_comp_attach_table_group(npucomp, pe);

        list_for_each_entry(npdev, &pe->phb->hose->bus->devices, bus_list) {
                struct pci_dev *gpdevtmp = pnv_pci_get_gpu_dev(npdev);

                if (gpdevtmp != gpdev)
                        continue;

                iommu_add_device(table_group, &npdev->dev);
        }

        return table_group;
}

void pnv_pci_npu_setup_iommu_groups(void)
{
        struct pci_controller *hose;
        struct pnv_phb *phb;
        struct pnv_ioda_pe *pe;

        /*
         * For non-nvlink devices the IOMMU group is registered when the PE is
         * configured and devices are added to the group when the per-device
         * DMA setup is run. That's done in hose->ops.dma_dev_setup() which is
         * only initialise for "normal" IODA PHBs.
         *
         * For NVLink devices we need to ensure the NVLinks and the GPU end up
         * in the same IOMMU group, so that's handled here.
         */
        list_for_each_entry(hose, &hose_list, list_node) {
                phb = hose->private_data;

                if (phb->type == PNV_PHB_IODA2)
                        list_for_each_entry(pe, &phb->ioda.pe_list, list)
                                pnv_try_setup_npu_table_group(pe);
        }

        /*
         * Now we have all PHBs discovered, time to add NPU devices to
         * the corresponding IOMMU groups.
         */
        list_for_each_entry(hose, &hose_list, list_node) {
                unsigned long  pgsizes;

                phb = hose->private_data;

                if (phb->type != PNV_PHB_NPU_NVLINK)
                        continue;

                pgsizes = pnv_ioda_parse_tce_sizes(phb);
                list_for_each_entry(pe, &phb->ioda.pe_list, list) {
                        /*
                         * IODA2 bridges get this set up from
                         * pci_controller_ops::setup_bridge but NPU bridges
                         * do not have this hook defined so we do it here.
                         */
                        pe->table_group.pgsizes = pgsizes;
                        pnv_npu_compound_attach(pe);
                }
        }
}
#endif /* CONFIG_IOMMU_API */

int pnv_npu2_init(struct pci_controller *hose)
{
        static int npu_index;
        struct npu *npu;
        int ret;

        npu = kzalloc(sizeof(*npu), GFP_KERNEL);
        if (!npu)
                return -ENOMEM;

        npu_index++;
        if (WARN_ON(npu_index >= NV_MAX_NPUS)) {
                ret = -ENOSPC;
                goto fail_exit;
        }
        npu->index = npu_index;
        hose->npu = npu;

        return 0;

fail_exit:
        kfree(npu);
        return ret;
}

int pnv_npu2_map_lpar_dev(struct pci_dev *gpdev, unsigned int lparid,
                unsigned long msr)
{
        int ret;
        struct pci_dev *npdev = pnv_pci_get_npu_dev(gpdev, 0);
        struct pci_controller *hose;
        struct pnv_phb *nphb;

        if (!npdev)
                return -ENODEV;

        hose = pci_bus_to_host(npdev->bus);
        nphb = hose->private_data;

        dev_dbg(&gpdev->dev, "Map LPAR opalid=%llu lparid=%u\n",
                        nphb->opal_id, lparid);
        /*
         * Currently we only support radix and non-zero LPCR only makes sense
         * for hash tables so skiboot expects the LPCR parameter to be a zero.
         */
        ret = opal_npu_map_lpar(nphb->opal_id, pci_dev_id(gpdev), lparid,
                                0 /* LPCR bits */);
        if (ret) {
                dev_err(&gpdev->dev, "Error %d mapping device to LPAR\n", ret);
                return ret;
        }

        dev_dbg(&gpdev->dev, "init context opalid=%llu msr=%lx\n",
                        nphb->opal_id, msr);
        ret = opal_npu_init_context(nphb->opal_id, 0/*__unused*/, msr,
                                    pci_dev_id(gpdev));
        if (ret < 0)
                dev_err(&gpdev->dev, "Failed to init context: %d\n", ret);
        else
                ret = 0;

        return 0;
}
EXPORT_SYMBOL_GPL(pnv_npu2_map_lpar_dev);

void pnv_npu2_map_lpar(struct pnv_ioda_pe *gpe, unsigned long msr)
{
        struct pci_dev *gpdev;

        list_for_each_entry(gpdev, &gpe->pbus->devices, bus_list)
                pnv_npu2_map_lpar_dev(gpdev, 0, msr);
}

int pnv_npu2_unmap_lpar_dev(struct pci_dev *gpdev)
{
        int ret;
        struct pci_dev *npdev = pnv_pci_get_npu_dev(gpdev, 0);
        struct pci_controller *hose;
        struct pnv_phb *nphb;

        if (!npdev)
                return -ENODEV;

        hose = pci_bus_to_host(npdev->bus);
        nphb = hose->private_data;

        dev_dbg(&gpdev->dev, "destroy context opalid=%llu\n",
                        nphb->opal_id);
        ret = opal_npu_destroy_context(nphb->opal_id, 0/*__unused*/,
                                       pci_dev_id(gpdev));
        if (ret < 0) {
                dev_err(&gpdev->dev, "Failed to destroy context: %d\n", ret);
                return ret;
        }

        /* Set LPID to 0 anyway, just to be safe */
        dev_dbg(&gpdev->dev, "Map LPAR opalid=%llu lparid=0\n", nphb->opal_id);
        ret = opal_npu_map_lpar(nphb->opal_id, pci_dev_id(gpdev), 0 /*LPID*/,
                                0 /* LPCR bits */);
        if (ret)
                dev_err(&gpdev->dev, "Error %d mapping device to LPAR\n", ret);

        return ret;
}
EXPORT_SYMBOL_GPL(pnv_npu2_unmap_lpar_dev);