WIP FPC-III support

[linux/fpc-iii.git] / arch / powerpc / platforms / pseries / iommu.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Copyright (C) 2001 Mike Corrigan & Dave Engebretsen, IBM Corporation
 *
 * Rewrite, cleanup:
 *
 * Copyright (C) 2004 Olof Johansson <olof@lixom.net>, IBM Corporation
 * Copyright (C) 2006 Olof Johansson <olof@lixom.net>
 *
 * Dynamic DMA mapping support, pSeries-specific parts, both SMP and LPAR.
 */

#include <linux/init.h>
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/mm.h>
#include <linux/memblock.h>
#include <linux/spinlock.h>
#include <linux/string.h>
#include <linux/pci.h>
#include <linux/dma-mapping.h>
#include <linux/crash_dump.h>
#include <linux/memory.h>
#include <linux/of.h>
#include <linux/iommu.h>
#include <linux/rculist.h>
#include <asm/io.h>
#include <asm/prom.h>
#include <asm/rtas.h>
#include <asm/iommu.h>
#include <asm/pci-bridge.h>
#include <asm/machdep.h>
#include <asm/firmware.h>
#include <asm/tce.h>
#include <asm/ppc-pci.h>
#include <asm/udbg.h>
#include <asm/mmzone.h>
#include <asm/plpar_wrappers.h>

#include "pseries.h"

enum {
        DDW_QUERY_PE_DMA_WIN  = 0,
        DDW_CREATE_PE_DMA_WIN = 1,
        DDW_REMOVE_PE_DMA_WIN = 2,

        DDW_APPLICABLE_SIZE
};

enum {
        DDW_EXT_SIZE = 0,
        DDW_EXT_RESET_DMA_WIN = 1,
        DDW_EXT_QUERY_OUT_SIZE = 2
};

static struct iommu_table_group *iommu_pseries_alloc_group(int node)
{
        struct iommu_table_group *table_group;
        struct iommu_table *tbl;

        table_group = kzalloc_node(sizeof(struct iommu_table_group), GFP_KERNEL,
                           node);
        if (!table_group)
                return NULL;

        tbl = kzalloc_node(sizeof(struct iommu_table), GFP_KERNEL, node);
        if (!tbl)
                goto free_group;

        INIT_LIST_HEAD_RCU(&tbl->it_group_list);
        kref_init(&tbl->it_kref);

        table_group->tables[0] = tbl;

        return table_group;

free_group:
        kfree(table_group);
        return NULL;
}

static void iommu_pseries_free_group(struct iommu_table_group *table_group,
                const char *node_name)
{
        struct iommu_table *tbl;

        if (!table_group)
                return;

        tbl = table_group->tables[0];
#ifdef CONFIG_IOMMU_API
        if (table_group->group) {
                iommu_group_put(table_group->group);
                BUG_ON(table_group->group);
        }
#endif
        iommu_tce_table_put(tbl);

        kfree(table_group);
}

static int tce_build_pSeries(struct iommu_table *tbl, long index,
                              long npages, unsigned long uaddr,
                              enum dma_data_direction direction,
                              unsigned long attrs)
{
        u64 proto_tce;
        __be64 *tcep;
        u64 rpn;

        proto_tce = TCE_PCI_READ; // Read allowed

        if (direction != DMA_TO_DEVICE)
                proto_tce |= TCE_PCI_WRITE;

        tcep = ((__be64 *)tbl->it_base) + index;

        while (npages--) {
                /* can't move this out since we might cross MEMBLOCK boundary */
                rpn = __pa(uaddr) >> TCE_SHIFT;
                *tcep = cpu_to_be64(proto_tce | (rpn & TCE_RPN_MASK) << TCE_RPN_SHIFT);

                uaddr += TCE_PAGE_SIZE;
                tcep++;
        }
        return 0;
}


static void tce_free_pSeries(struct iommu_table *tbl, long index, long npages)
{
        __be64 *tcep;

        tcep = ((__be64 *)tbl->it_base) + index;

        while (npages--)
                *(tcep++) = 0;
}

static unsigned long tce_get_pseries(struct iommu_table *tbl, long index)
{
        __be64 *tcep;

        tcep = ((__be64 *)tbl->it_base) + index;

        return be64_to_cpu(*tcep);
}

static void tce_free_pSeriesLP(unsigned long liobn, long, long);
static void tce_freemulti_pSeriesLP(struct iommu_table*, long, long);

static int tce_build_pSeriesLP(unsigned long liobn, long tcenum, long tceshift,
                                long npages, unsigned long uaddr,
                                enum dma_data_direction direction,
                                unsigned long attrs)
{
        u64 rc = 0;
        u64 proto_tce, tce;
        u64 rpn;
        int ret = 0;
        long tcenum_start = tcenum, npages_start = npages;

        rpn = __pa(uaddr) >> tceshift;
        proto_tce = TCE_PCI_READ;
        if (direction != DMA_TO_DEVICE)
                proto_tce |= TCE_PCI_WRITE;

        while (npages--) {
                tce = proto_tce | (rpn & TCE_RPN_MASK) << tceshift;
                rc = plpar_tce_put((u64)liobn, (u64)tcenum << tceshift, tce);

                if (unlikely(rc == H_NOT_ENOUGH_RESOURCES)) {
                        ret = (int)rc;
                        tce_free_pSeriesLP(liobn, tcenum_start,
                                           (npages_start - (npages + 1)));
                        break;
                }

                if (rc && printk_ratelimit()) {
                        printk("tce_build_pSeriesLP: plpar_tce_put failed. rc=%lld\n", rc);
                        printk("\tindex   = 0x%llx\n", (u64)liobn);
                        printk("\ttcenum  = 0x%llx\n", (u64)tcenum);
                        printk("\ttce val = 0x%llx\n", tce );
                        dump_stack();
                }

                tcenum++;
                rpn++;
        }
        return ret;
}

static DEFINE_PER_CPU(__be64 *, tce_page);

static int tce_buildmulti_pSeriesLP(struct iommu_table *tbl, long tcenum,
                                     long npages, unsigned long uaddr,
                                     enum dma_data_direction direction,
                                     unsigned long attrs)
{
        u64 rc = 0;
        u64 proto_tce;
        __be64 *tcep;
        u64 rpn;
        long l, limit;
        long tcenum_start = tcenum, npages_start = npages;
        int ret = 0;
        unsigned long flags;

        if ((npages == 1) || !firmware_has_feature(FW_FEATURE_PUT_TCE_IND)) {
                return tce_build_pSeriesLP(tbl->it_index, tcenum,
                                           tbl->it_page_shift, npages, uaddr,
                                           direction, attrs);
        }

        local_irq_save(flags);  /* to protect tcep and the page behind it */

        tcep = __this_cpu_read(tce_page);

        /* This is safe to do since interrupts are off when we're called
         * from iommu_alloc{,_sg}()
         */
        if (!tcep) {
                tcep = (__be64 *)__get_free_page(GFP_ATOMIC);
                /* If allocation fails, fall back to the loop implementation */
                if (!tcep) {
                        local_irq_restore(flags);
                        return tce_build_pSeriesLP(tbl->it_index, tcenum,
                                        tbl->it_page_shift,
                                        npages, uaddr, direction, attrs);
                }
                __this_cpu_write(tce_page, tcep);
        }

        rpn = __pa(uaddr) >> TCE_SHIFT;
        proto_tce = TCE_PCI_READ;
        if (direction != DMA_TO_DEVICE)
                proto_tce |= TCE_PCI_WRITE;

        /* We can map max one pageful of TCEs at a time */
        do {
                /*
                 * Set up the page with TCE data, looping through and setting
                 * the values.
                 */
                limit = min_t(long, npages, 4096/TCE_ENTRY_SIZE);

                for (l = 0; l < limit; l++) {
                        tcep[l] = cpu_to_be64(proto_tce | (rpn & TCE_RPN_MASK) << TCE_RPN_SHIFT);
                        rpn++;
                }

                rc = plpar_tce_put_indirect((u64)tbl->it_index,
                                            (u64)tcenum << 12,
                                            (u64)__pa(tcep),
                                            limit);

                npages -= limit;
                tcenum += limit;
        } while (npages > 0 && !rc);

        local_irq_restore(flags);

        if (unlikely(rc == H_NOT_ENOUGH_RESOURCES)) {
                ret = (int)rc;
                tce_freemulti_pSeriesLP(tbl, tcenum_start,
                                        (npages_start - (npages + limit)));
                return ret;
        }

        if (rc && printk_ratelimit()) {
                printk("tce_buildmulti_pSeriesLP: plpar_tce_put failed. rc=%lld\n", rc);
                printk("\tindex   = 0x%llx\n", (u64)tbl->it_index);
                printk("\tnpages  = 0x%llx\n", (u64)npages);
                printk("\ttce[0] val = 0x%llx\n", tcep[0]);
                dump_stack();
        }
        return ret;
}

static void tce_free_pSeriesLP(unsigned long liobn, long tcenum, long npages)
{
        u64 rc;

        while (npages--) {
                rc = plpar_tce_put((u64)liobn, (u64)tcenum << 12, 0);

                if (rc && printk_ratelimit()) {
                        printk("tce_free_pSeriesLP: plpar_tce_put failed. rc=%lld\n", rc);
                        printk("\tindex   = 0x%llx\n", (u64)liobn);
                        printk("\ttcenum  = 0x%llx\n", (u64)tcenum);
                        dump_stack();
                }

                tcenum++;
        }
}


static void tce_freemulti_pSeriesLP(struct iommu_table *tbl, long tcenum, long npages)
{
        u64 rc;

        if (!firmware_has_feature(FW_FEATURE_STUFF_TCE))
                return tce_free_pSeriesLP(tbl->it_index, tcenum, npages);

        rc = plpar_tce_stuff((u64)tbl->it_index, (u64)tcenum << 12, 0, npages);

        if (rc && printk_ratelimit()) {
                printk("tce_freemulti_pSeriesLP: plpar_tce_stuff failed\n");
                printk("\trc      = %lld\n", rc);
                printk("\tindex   = 0x%llx\n", (u64)tbl->it_index);
                printk("\tnpages  = 0x%llx\n", (u64)npages);
                dump_stack();
        }
}

static unsigned long tce_get_pSeriesLP(struct iommu_table *tbl, long tcenum)
{
        u64 rc;
        unsigned long tce_ret;

        rc = plpar_tce_get((u64)tbl->it_index, (u64)tcenum << 12, &tce_ret);

        if (rc && printk_ratelimit()) {
                printk("tce_get_pSeriesLP: plpar_tce_get failed. rc=%lld\n", rc);
                printk("\tindex   = 0x%llx\n", (u64)tbl->it_index);
                printk("\ttcenum  = 0x%llx\n", (u64)tcenum);
                dump_stack();
        }

        return tce_ret;
}

/* this is compatible with cells for the device tree property */
struct dynamic_dma_window_prop {
        __be32  liobn;          /* tce table number */
        __be64  dma_base;       /* address hi,lo */
        __be32  tce_shift;      /* ilog2(tce_page_size) */
        __be32  window_shift;   /* ilog2(tce_window_size) */
};

struct direct_window {
        struct device_node *device;
        const struct dynamic_dma_window_prop *prop;
        struct list_head list;
};

/* Dynamic DMA Window support */
struct ddw_query_response {
        u32 windows_available;
        u64 largest_available_block;
        u32 page_size;
        u32 migration_capable;
};

struct ddw_create_response {
        u32 liobn;
        u32 addr_hi;
        u32 addr_lo;
};

static LIST_HEAD(direct_window_list);
/* prevents races between memory on/offline and window creation */
static DEFINE_SPINLOCK(direct_window_list_lock);
/* protects initializing window twice for same device */
static DEFINE_MUTEX(direct_window_init_mutex);
#define DIRECT64_PROPNAME "linux,direct64-ddr-window-info"

static int tce_clearrange_multi_pSeriesLP(unsigned long start_pfn,
                                        unsigned long num_pfn, const void *arg)
{
        const struct dynamic_dma_window_prop *maprange = arg;
        int rc;
        u64 tce_size, num_tce, dma_offset, next;
        u32 tce_shift;
        long limit;

        tce_shift = be32_to_cpu(maprange->tce_shift);
        tce_size = 1ULL << tce_shift;
        next = start_pfn << PAGE_SHIFT;
        num_tce = num_pfn << PAGE_SHIFT;

        /* round back to the beginning of the tce page size */
        num_tce += next & (tce_size - 1);
        next &= ~(tce_size - 1);

        /* covert to number of tces */
        num_tce |= tce_size - 1;
        num_tce >>= tce_shift;

        do {
                /*
                 * Set up the page with TCE data, looping through and setting
                 * the values.
                 */
                limit = min_t(long, num_tce, 512);
                dma_offset = next + be64_to_cpu(maprange->dma_base);

                rc = plpar_tce_stuff((u64)be32_to_cpu(maprange->liobn),
                                             dma_offset,
                                             0, limit);
                next += limit * tce_size;
                num_tce -= limit;
        } while (num_tce > 0 && !rc);

        return rc;
}

static int tce_setrange_multi_pSeriesLP(unsigned long start_pfn,
                                        unsigned long num_pfn, const void *arg)
{
        const struct dynamic_dma_window_prop *maprange = arg;
        u64 tce_size, num_tce, dma_offset, next, proto_tce, liobn;
        __be64 *tcep;
        u32 tce_shift;
        u64 rc = 0;
        long l, limit;

        if (!firmware_has_feature(FW_FEATURE_PUT_TCE_IND)) {
                unsigned long tceshift = be32_to_cpu(maprange->tce_shift);
                unsigned long dmastart = (start_pfn << PAGE_SHIFT) +
                                be64_to_cpu(maprange->dma_base);
                unsigned long tcenum = dmastart >> tceshift;
                unsigned long npages = num_pfn << PAGE_SHIFT >> tceshift;
                void *uaddr = __va(start_pfn << PAGE_SHIFT);

                return tce_build_pSeriesLP(be32_to_cpu(maprange->liobn),
                                tcenum, tceshift, npages, (unsigned long) uaddr,
                                DMA_BIDIRECTIONAL, 0);
        }

        local_irq_disable();    /* to protect tcep and the page behind it */
        tcep = __this_cpu_read(tce_page);

        if (!tcep) {
                tcep = (__be64 *)__get_free_page(GFP_ATOMIC);
                if (!tcep) {
                        local_irq_enable();
                        return -ENOMEM;
                }
                __this_cpu_write(tce_page, tcep);
        }

        proto_tce = TCE_PCI_READ | TCE_PCI_WRITE;

        liobn = (u64)be32_to_cpu(maprange->liobn);
        tce_shift = be32_to_cpu(maprange->tce_shift);
        tce_size = 1ULL << tce_shift;
        next = start_pfn << PAGE_SHIFT;
        num_tce = num_pfn << PAGE_SHIFT;

        /* round back to the beginning of the tce page size */
        num_tce += next & (tce_size - 1);
        next &= ~(tce_size - 1);

        /* covert to number of tces */
        num_tce |= tce_size - 1;
        num_tce >>= tce_shift;

        /* We can map max one pageful of TCEs at a time */
        do {
                /*
                 * Set up the page with TCE data, looping through and setting
                 * the values.
                 */
                limit = min_t(long, num_tce, 4096/TCE_ENTRY_SIZE);
                dma_offset = next + be64_to_cpu(maprange->dma_base);

                for (l = 0; l < limit; l++) {
                        tcep[l] = cpu_to_be64(proto_tce | next);
                        next += tce_size;
                }

                rc = plpar_tce_put_indirect(liobn,
                                            dma_offset,
                                            (u64)__pa(tcep),
                                            limit);

                num_tce -= limit;
        } while (num_tce > 0 && !rc);

        /* error cleanup: caller will clear whole range */

        local_irq_enable();
        return rc;
}

static int tce_setrange_multi_pSeriesLP_walk(unsigned long start_pfn,
                unsigned long num_pfn, void *arg)
{
        return tce_setrange_multi_pSeriesLP(start_pfn, num_pfn, arg);
}

static void iommu_table_setparms(struct pci_controller *phb,
                                 struct device_node *dn,
                                 struct iommu_table *tbl)
{
        struct device_node *node;
        const unsigned long *basep;
        const u32 *sizep;

        node = phb->dn;

        basep = of_get_property(node, "linux,tce-base", NULL);
        sizep = of_get_property(node, "linux,tce-size", NULL);
        if (basep == NULL || sizep == NULL) {
                printk(KERN_ERR "PCI_DMA: iommu_table_setparms: %pOF has "
                                "missing tce entries !\n", dn);
                return;
        }

        tbl->it_base = (unsigned long)__va(*basep);

        if (!is_kdump_kernel())
                memset((void *)tbl->it_base, 0, *sizep);

        tbl->it_busno = phb->bus->number;
        tbl->it_page_shift = IOMMU_PAGE_SHIFT_4K;

        /* Units of tce entries */
        tbl->it_offset = phb->dma_window_base_cur >> tbl->it_page_shift;

        /* Test if we are going over 2GB of DMA space */
        if (phb->dma_window_base_cur + phb->dma_window_size > 0x80000000ul) {
                udbg_printf("PCI_DMA: Unexpected number of IOAs under this PHB.\n");
                panic("PCI_DMA: Unexpected number of IOAs under this PHB.\n");
        }

        phb->dma_window_base_cur += phb->dma_window_size;

        /* Set the tce table size - measured in entries */
        tbl->it_size = phb->dma_window_size >> tbl->it_page_shift;

        tbl->it_index = 0;
        tbl->it_blocksize = 16;
        tbl->it_type = TCE_PCI;
}

/*
 * iommu_table_setparms_lpar
 *
 * Function: On pSeries LPAR systems, return TCE table info, given a pci bus.
 */
static void iommu_table_setparms_lpar(struct pci_controller *phb,
                                      struct device_node *dn,
                                      struct iommu_table *tbl,
                                      struct iommu_table_group *table_group,
                                      const __be32 *dma_window)
{
        unsigned long offset, size;

        of_parse_dma_window(dn, dma_window, &tbl->it_index, &offset, &size);

        tbl->it_busno = phb->bus->number;
        tbl->it_page_shift = IOMMU_PAGE_SHIFT_4K;
        tbl->it_base   = 0;
        tbl->it_blocksize  = 16;
        tbl->it_type = TCE_PCI;
        tbl->it_offset = offset >> tbl->it_page_shift;
        tbl->it_size = size >> tbl->it_page_shift;

        table_group->tce32_start = offset;
        table_group->tce32_size = size;
}

struct iommu_table_ops iommu_table_pseries_ops = {
        .set = tce_build_pSeries,
        .clear = tce_free_pSeries,
        .get = tce_get_pseries
};

static void pci_dma_bus_setup_pSeries(struct pci_bus *bus)
{
        struct device_node *dn;
        struct iommu_table *tbl;
        struct device_node *isa_dn, *isa_dn_orig;
        struct device_node *tmp;
        struct pci_dn *pci;
        int children;

        dn = pci_bus_to_OF_node(bus);

        pr_debug("pci_dma_bus_setup_pSeries: setting up bus %pOF\n", dn);

        if (bus->self) {
                /* This is not a root bus, any setup will be done for the
                 * device-side of the bridge in iommu_dev_setup_pSeries().
                 */
                return;
        }
        pci = PCI_DN(dn);

        /* Check if the ISA bus on the system is under
         * this PHB.
         */
        isa_dn = isa_dn_orig = of_find_node_by_type(NULL, "isa");

        while (isa_dn && isa_dn != dn)
                isa_dn = isa_dn->parent;

        of_node_put(isa_dn_orig);

        /* Count number of direct PCI children of the PHB. */
        for (children = 0, tmp = dn->child; tmp; tmp = tmp->sibling)
                children++;

        pr_debug("Children: %d\n", children);

        /* Calculate amount of DMA window per slot. Each window must be
         * a power of two (due to pci_alloc_consistent requirements).
         *
         * Keep 256MB aside for PHBs with ISA.
         */

        if (!isa_dn) {
                /* No ISA/IDE - just set window size and return */
                pci->phb->dma_window_size = 0x80000000ul; /* To be divided */

                while (pci->phb->dma_window_size * children > 0x80000000ul)
                        pci->phb->dma_window_size >>= 1;
                pr_debug("No ISA/IDE, window size is 0x%llx\n",
                         pci->phb->dma_window_size);
                pci->phb->dma_window_base_cur = 0;

                return;
        }

        /* If we have ISA, then we probably have an IDE
         * controller too. Allocate a 128MB table but
         * skip the first 128MB to avoid stepping on ISA
         * space.
         */
        pci->phb->dma_window_size = 0x8000000ul;
        pci->phb->dma_window_base_cur = 0x8000000ul;

        pci->table_group = iommu_pseries_alloc_group(pci->phb->node);
        tbl = pci->table_group->tables[0];

        iommu_table_setparms(pci->phb, dn, tbl);
        tbl->it_ops = &iommu_table_pseries_ops;
        iommu_init_table(tbl, pci->phb->node, 0, 0);

        /* Divide the rest (1.75GB) among the children */
        pci->phb->dma_window_size = 0x80000000ul;
        while (pci->phb->dma_window_size * children > 0x70000000ul)
                pci->phb->dma_window_size >>= 1;

        pr_debug("ISA/IDE, window size is 0x%llx\n", pci->phb->dma_window_size);
}

#ifdef CONFIG_IOMMU_API
static int tce_exchange_pseries(struct iommu_table *tbl, long index, unsigned
                                long *tce, enum dma_data_direction *direction,
                                bool realmode)
{
        long rc;
        unsigned long ioba = (unsigned long) index << tbl->it_page_shift;
        unsigned long flags, oldtce = 0;
        u64 proto_tce = iommu_direction_to_tce_perm(*direction);
        unsigned long newtce = *tce | proto_tce;

        spin_lock_irqsave(&tbl->large_pool.lock, flags);

        rc = plpar_tce_get((u64)tbl->it_index, ioba, &oldtce);
        if (!rc)
                rc = plpar_tce_put((u64)tbl->it_index, ioba, newtce);

        if (!rc) {
                *direction = iommu_tce_direction(oldtce);
                *tce = oldtce & ~(TCE_PCI_READ | TCE_PCI_WRITE);
        }

        spin_unlock_irqrestore(&tbl->large_pool.lock, flags);

        return rc;
}
#endif

struct iommu_table_ops iommu_table_lpar_multi_ops = {
        .set = tce_buildmulti_pSeriesLP,
#ifdef CONFIG_IOMMU_API
        .xchg_no_kill = tce_exchange_pseries,
#endif
        .clear = tce_freemulti_pSeriesLP,
        .get = tce_get_pSeriesLP
};

static void pci_dma_bus_setup_pSeriesLP(struct pci_bus *bus)
{
        struct iommu_table *tbl;
        struct device_node *dn, *pdn;
        struct pci_dn *ppci;
        const __be32 *dma_window = NULL;

        dn = pci_bus_to_OF_node(bus);

        pr_debug("pci_dma_bus_setup_pSeriesLP: setting up bus %pOF\n",
                 dn);

        /* Find nearest ibm,dma-window, walking up the device tree */
        for (pdn = dn; pdn != NULL; pdn = pdn->parent) {
                dma_window = of_get_property(pdn, "ibm,dma-window", NULL);
                if (dma_window != NULL)
                        break;
        }

        if (dma_window == NULL) {
                pr_debug("  no ibm,dma-window property !\n");
                return;
        }

        ppci = PCI_DN(pdn);

        pr_debug("  parent is %pOF, iommu_table: 0x%p\n",
                 pdn, ppci->table_group);

        if (!ppci->table_group) {
                ppci->table_group = iommu_pseries_alloc_group(ppci->phb->node);
                tbl = ppci->table_group->tables[0];
                iommu_table_setparms_lpar(ppci->phb, pdn, tbl,
                                ppci->table_group, dma_window);
                tbl->it_ops = &iommu_table_lpar_multi_ops;
                iommu_init_table(tbl, ppci->phb->node, 0, 0);
                iommu_register_group(ppci->table_group,
                                pci_domain_nr(bus), 0);
                pr_debug("  created table: %p\n", ppci->table_group);
        }
}


static void pci_dma_dev_setup_pSeries(struct pci_dev *dev)
{
        struct device_node *dn;
        struct iommu_table *tbl;

        pr_debug("pci_dma_dev_setup_pSeries: %s\n", pci_name(dev));

        dn = dev->dev.of_node;

        /* If we're the direct child of a root bus, then we need to allocate
         * an iommu table ourselves. The bus setup code should have setup
         * the window sizes already.
         */
        if (!dev->bus->self) {
                struct pci_controller *phb = PCI_DN(dn)->phb;

                pr_debug(" --> first child, no bridge. Allocating iommu table.\n");
                PCI_DN(dn)->table_group = iommu_pseries_alloc_group(phb->node);
                tbl = PCI_DN(dn)->table_group->tables[0];
                iommu_table_setparms(phb, dn, tbl);
                tbl->it_ops = &iommu_table_pseries_ops;
                iommu_init_table(tbl, phb->node, 0, 0);
                set_iommu_table_base(&dev->dev, tbl);
                return;
        }

        /* If this device is further down the bus tree, search upwards until
         * an already allocated iommu table is found and use that.
         */

        while (dn && PCI_DN(dn) && PCI_DN(dn)->table_group == NULL)
                dn = dn->parent;

        if (dn && PCI_DN(dn))
                set_iommu_table_base(&dev->dev,
                                PCI_DN(dn)->table_group->tables[0]);
        else
                printk(KERN_WARNING "iommu: Device %s has no iommu table\n",
                       pci_name(dev));
}

static int __read_mostly disable_ddw;

static int __init disable_ddw_setup(char *str)
{
        disable_ddw = 1;
        printk(KERN_INFO "ppc iommu: disabling ddw.\n");

        return 0;
}

early_param("disable_ddw", disable_ddw_setup);

static void remove_dma_window(struct device_node *np, u32 *ddw_avail,
                              struct property *win)
{
        struct dynamic_dma_window_prop *dwp;
        u64 liobn;
        int ret;

        dwp = win->value;
        liobn = (u64)be32_to_cpu(dwp->liobn);

        /* clear the whole window, note the arg is in kernel pages */
        ret = tce_clearrange_multi_pSeriesLP(0,
                1ULL << (be32_to_cpu(dwp->window_shift) - PAGE_SHIFT), dwp);
        if (ret)
                pr_warn("%pOF failed to clear tces in window.\n",
                        np);
        else
                pr_debug("%pOF successfully cleared tces in window.\n",
                         np);

        ret = rtas_call(ddw_avail[DDW_REMOVE_PE_DMA_WIN], 1, 1, NULL, liobn);
        if (ret)
                pr_warn("%pOF: failed to remove direct window: rtas returned "
                        "%d to ibm,remove-pe-dma-window(%x) %llx\n",
                        np, ret, ddw_avail[DDW_REMOVE_PE_DMA_WIN], liobn);
        else
                pr_debug("%pOF: successfully removed direct window: rtas returned "
                        "%d to ibm,remove-pe-dma-window(%x) %llx\n",
                        np, ret, ddw_avail[DDW_REMOVE_PE_DMA_WIN], liobn);
}

static void remove_ddw(struct device_node *np, bool remove_prop)
{
        struct property *win;
        u32 ddw_avail[DDW_APPLICABLE_SIZE];
        int ret = 0;

        ret = of_property_read_u32_array(np, "ibm,ddw-applicable",
                                         &ddw_avail[0], DDW_APPLICABLE_SIZE);
        if (ret)
                return;

        win = of_find_property(np, DIRECT64_PROPNAME, NULL);
        if (!win)
                return;

        if (win->length >= sizeof(struct dynamic_dma_window_prop))
                remove_dma_window(np, ddw_avail, win);

        if (!remove_prop)
                return;

        ret = of_remove_property(np, win);
        if (ret)
                pr_warn("%pOF: failed to remove direct window property: %d\n",
                        np, ret);
}

static u64 find_existing_ddw(struct device_node *pdn, int *window_shift)
{
        struct direct_window *window;
        const struct dynamic_dma_window_prop *direct64;
        u64 dma_addr = 0;

        spin_lock(&direct_window_list_lock);
        /* check if we already created a window and dupe that config if so */
        list_for_each_entry(window, &direct_window_list, list) {
                if (window->device == pdn) {
                        direct64 = window->prop;
                        dma_addr = be64_to_cpu(direct64->dma_base);
                        *window_shift = be32_to_cpu(direct64->window_shift);
                        break;
                }
        }
        spin_unlock(&direct_window_list_lock);

        return dma_addr;
}

static int find_existing_ddw_windows(void)
{
        int len;
        struct device_node *pdn;
        struct direct_window *window;
        const struct dynamic_dma_window_prop *direct64;

        if (!firmware_has_feature(FW_FEATURE_LPAR))
                return 0;

        for_each_node_with_property(pdn, DIRECT64_PROPNAME) {
                direct64 = of_get_property(pdn, DIRECT64_PROPNAME, &len);
                if (!direct64)
                        continue;

                window = kzalloc(sizeof(*window), GFP_KERNEL);
                if (!window || len < sizeof(struct dynamic_dma_window_prop)) {
                        kfree(window);
                        remove_ddw(pdn, true);
                        continue;
                }

                window->device = pdn;
                window->prop = direct64;
                spin_lock(&direct_window_list_lock);
                list_add(&window->list, &direct_window_list);
                spin_unlock(&direct_window_list_lock);
        }

        return 0;
}
machine_arch_initcall(pseries, find_existing_ddw_windows);

/**
 * ddw_read_ext - Get the value of an DDW extension
 * @np:         device node from which the extension value is to be read.
 * @extnum:     index number of the extension.
 * @value:      pointer to return value, modified when extension is available.
 *
 * Checks if "ibm,ddw-extensions" exists for this node, and get the value
 * on index 'extnum'.
 * It can be used only to check if a property exists, passing value == NULL.
 *
 * Returns:
 *      0 if extension successfully read
 *      -EINVAL if the "ibm,ddw-extensions" does not exist,
 *      -ENODATA if "ibm,ddw-extensions" does not have a value, and
 *      -EOVERFLOW if "ibm,ddw-extensions" does not contain this extension.
 */
static inline int ddw_read_ext(const struct device_node *np, int extnum,
                               u32 *value)
{
        static const char propname[] = "ibm,ddw-extensions";
        u32 count;
        int ret;

        ret = of_property_read_u32_index(np, propname, DDW_EXT_SIZE, &count);
        if (ret)
                return ret;

        if (count < extnum)
                return -EOVERFLOW;

        if (!value)
                value = &count;

        return of_property_read_u32_index(np, propname, extnum, value);
}

static int query_ddw(struct pci_dev *dev, const u32 *ddw_avail,
                     struct ddw_query_response *query,
                     struct device_node *parent)
{
        struct device_node *dn;
        struct pci_dn *pdn;
        u32 cfg_addr, ext_query, query_out[5];
        u64 buid;
        int ret, out_sz;

        /*
         * From LoPAR level 2.8, "ibm,ddw-extensions" index 3 can rule how many
         * output parameters ibm,query-pe-dma-windows will have, ranging from
         * 5 to 6.
         */
        ret = ddw_read_ext(parent, DDW_EXT_QUERY_OUT_SIZE, &ext_query);
        if (!ret && ext_query == 1)
                out_sz = 6;
        else
                out_sz = 5;

        /*
         * Get the config address and phb buid of the PE window.
         * Rely on eeh to retrieve this for us.
         * Retrieve them from the pci device, not the node with the
         * dma-window property
         */
        dn = pci_device_to_OF_node(dev);
        pdn = PCI_DN(dn);
        buid = pdn->phb->buid;
        cfg_addr = ((pdn->busno << 16) | (pdn->devfn << 8));

        ret = rtas_call(ddw_avail[DDW_QUERY_PE_DMA_WIN], 3, out_sz, query_out,
                        cfg_addr, BUID_HI(buid), BUID_LO(buid));
        dev_info(&dev->dev, "ibm,query-pe-dma-windows(%x) %x %x %x returned %d\n",
                 ddw_avail[DDW_QUERY_PE_DMA_WIN], cfg_addr, BUID_HI(buid),
                 BUID_LO(buid), ret);

        switch (out_sz) {
        case 5:
                query->windows_available = query_out[0];
                query->largest_available_block = query_out[1];
                query->page_size = query_out[2];
                query->migration_capable = query_out[3];
                break;
        case 6:
                query->windows_available = query_out[0];
                query->largest_available_block = ((u64)query_out[1] << 32) |
                                                 query_out[2];
                query->page_size = query_out[3];
                query->migration_capable = query_out[4];
                break;
        }

        return ret;
}

static int create_ddw(struct pci_dev *dev, const u32 *ddw_avail,
                        struct ddw_create_response *create, int page_shift,
                        int window_shift)
{
        struct device_node *dn;
        struct pci_dn *pdn;
        u32 cfg_addr;
        u64 buid;
        int ret;

        /*
         * Get the config address and phb buid of the PE window.
         * Rely on eeh to retrieve this for us.
         * Retrieve them from the pci device, not the node with the
         * dma-window property
         */
        dn = pci_device_to_OF_node(dev);
        pdn = PCI_DN(dn);
        buid = pdn->phb->buid;
        cfg_addr = ((pdn->busno << 16) | (pdn->devfn << 8));

        do {
                /* extra outputs are LIOBN and dma-addr (hi, lo) */
                ret = rtas_call(ddw_avail[DDW_CREATE_PE_DMA_WIN], 5, 4,
                                (u32 *)create, cfg_addr, BUID_HI(buid),
                                BUID_LO(buid), page_shift, window_shift);
        } while (rtas_busy_delay(ret));
        dev_info(&dev->dev,
                "ibm,create-pe-dma-window(%x) %x %x %x %x %x returned %d "
                "(liobn = 0x%x starting addr = %x %x)\n",
                 ddw_avail[DDW_CREATE_PE_DMA_WIN], cfg_addr, BUID_HI(buid),
                 BUID_LO(buid), page_shift, window_shift, ret, create->liobn,
                 create->addr_hi, create->addr_lo);

        return ret;
}

struct failed_ddw_pdn {
        struct device_node *pdn;
        struct list_head list;
};

static LIST_HEAD(failed_ddw_pdn_list);

static phys_addr_t ddw_memory_hotplug_max(void)
{
        phys_addr_t max_addr = memory_hotplug_max();
        struct device_node *memory;

        /*
         * The "ibm,pmemory" can appear anywhere in the address space.
         * Assuming it is still backed by page structs, set the upper limit
         * for the huge DMA window as MAX_PHYSMEM_BITS.
         */
        if (of_find_node_by_type(NULL, "ibm,pmemory"))
                return (sizeof(phys_addr_t) * 8 <= MAX_PHYSMEM_BITS) ?
                        (phys_addr_t) -1 : (1ULL << MAX_PHYSMEM_BITS);

        for_each_node_by_type(memory, "memory") {
                unsigned long start, size;
                int n_mem_addr_cells, n_mem_size_cells, len;
                const __be32 *memcell_buf;

                memcell_buf = of_get_property(memory, "reg", &len);
                if (!memcell_buf || len <= 0)
                        continue;

                n_mem_addr_cells = of_n_addr_cells(memory);
                n_mem_size_cells = of_n_size_cells(memory);

                start = of_read_number(memcell_buf, n_mem_addr_cells);
                memcell_buf += n_mem_addr_cells;
                size = of_read_number(memcell_buf, n_mem_size_cells);
                memcell_buf += n_mem_size_cells;

                max_addr = max_t(phys_addr_t, max_addr, start + size);
        }

        return max_addr;
}

/*
 * Platforms supporting the DDW option starting with LoPAR level 2.7 implement
 * ibm,ddw-extensions, which carries the rtas token for
 * ibm,reset-pe-dma-windows.
 * That rtas-call can be used to restore the default DMA window for the device.
 */
static void reset_dma_window(struct pci_dev *dev, struct device_node *par_dn)
{
        int ret;
        u32 cfg_addr, reset_dma_win;
        u64 buid;
        struct device_node *dn;
        struct pci_dn *pdn;

        ret = ddw_read_ext(par_dn, DDW_EXT_RESET_DMA_WIN, &reset_dma_win);
        if (ret)
                return;

        dn = pci_device_to_OF_node(dev);
        pdn = PCI_DN(dn);
        buid = pdn->phb->buid;
        cfg_addr = (pdn->busno << 16) | (pdn->devfn << 8);

        ret = rtas_call(reset_dma_win, 3, 1, NULL, cfg_addr, BUID_HI(buid),
                        BUID_LO(buid));
        if (ret)
                dev_info(&dev->dev,
                         "ibm,reset-pe-dma-windows(%x) %x %x %x returned %d ",
                         reset_dma_win, cfg_addr, BUID_HI(buid), BUID_LO(buid),
                         ret);
}

/*
 * If the PE supports dynamic dma windows, and there is space for a table
 * that can map all pages in a linear offset, then setup such a table,
 * and record the dma-offset in the struct device.
 *
 * dev: the pci device we are checking
 * pdn: the parent pe node with the ibm,dma_window property
 * Future: also check if we can remap the base window for our base page size
 *
 * returns the dma offset for use by the direct mapped DMA code.
 */
static u64 enable_ddw(struct pci_dev *dev, struct device_node *pdn)
{
        int len = 0, ret;
        int max_ram_len = order_base_2(ddw_memory_hotplug_max());
        struct ddw_query_response query;
        struct ddw_create_response create;
        int page_shift;
        u64 dma_addr;
        struct device_node *dn;
        u32 ddw_avail[DDW_APPLICABLE_SIZE];
        struct direct_window *window;
        struct property *win64;
        struct dynamic_dma_window_prop *ddwprop;
        struct failed_ddw_pdn *fpdn;
        bool default_win_removed = false;
        bool pmem_present;

        dn = of_find_node_by_type(NULL, "ibm,pmemory");
        pmem_present = dn != NULL;
        of_node_put(dn);

        mutex_lock(&direct_window_init_mutex);

        dma_addr = find_existing_ddw(pdn, &len);
        if (dma_addr != 0)
                goto out_unlock;

        /*
         * If we already went through this for a previous function of
         * the same device and failed, we don't want to muck with the
         * DMA window again, as it will race with in-flight operations
         * and can lead to EEHs. The above mutex protects access to the
         * list.
         */
        list_for_each_entry(fpdn, &failed_ddw_pdn_list, list) {
                if (fpdn->pdn == pdn)
                        goto out_unlock;
        }

        /*
         * the ibm,ddw-applicable property holds the tokens for:
         * ibm,query-pe-dma-window
         * ibm,create-pe-dma-window
         * ibm,remove-pe-dma-window
         * for the given node in that order.
         * the property is actually in the parent, not the PE
         */
        ret = of_property_read_u32_array(pdn, "ibm,ddw-applicable",
                                         &ddw_avail[0], DDW_APPLICABLE_SIZE);
        if (ret)
                goto out_failed;

       /*
         * Query if there is a second window of size to map the
         * whole partition.  Query returns number of windows, largest
         * block assigned to PE (partition endpoint), and two bitmasks
         * of page sizes: supported and supported for migrate-dma.
         */
        dn = pci_device_to_OF_node(dev);
        ret = query_ddw(dev, ddw_avail, &query, pdn);
        if (ret != 0)
                goto out_failed;

        /*
         * If there is no window available, remove the default DMA window,
         * if it's present. This will make all the resources available to the
         * new DDW window.
         * If anything fails after this, we need to restore it, so also check
         * for extensions presence.
         */
        if (query.windows_available == 0) {
                struct property *default_win;
                int reset_win_ext;

                default_win = of_find_property(pdn, "ibm,dma-window", NULL);
                if (!default_win)
                        goto out_failed;

                reset_win_ext = ddw_read_ext(pdn, DDW_EXT_RESET_DMA_WIN, NULL);
                if (reset_win_ext)
                        goto out_failed;

                remove_dma_window(pdn, ddw_avail, default_win);
                default_win_removed = true;

                /* Query again, to check if the window is available */
                ret = query_ddw(dev, ddw_avail, &query, pdn);
                if (ret != 0)
                        goto out_failed;

                if (query.windows_available == 0) {
                        /* no windows are available for this device. */
                        dev_dbg(&dev->dev, "no free dynamic windows");
                        goto out_failed;
                }
        }
        if (query.page_size & 4) {
                page_shift = 24; /* 16MB */
        } else if (query.page_size & 2) {
                page_shift = 16; /* 64kB */
        } else if (query.page_size & 1) {
                page_shift = 12; /* 4kB */
        } else {
                dev_dbg(&dev->dev, "no supported direct page size in mask %x",
                          query.page_size);
                goto out_failed;
        }
        /* verify the window * number of ptes will map the partition */
        /* check largest block * page size > max memory hotplug addr */
        /*
         * The "ibm,pmemory" can appear anywhere in the address space.
         * Assuming it is still backed by page structs, try MAX_PHYSMEM_BITS
         * for the upper limit and fallback to max RAM otherwise but this
         * disables device::dma_ops_bypass.
         */
        len = max_ram_len;
        if (pmem_present) {
                if (query.largest_available_block >=
                    (1ULL << (MAX_PHYSMEM_BITS - page_shift)))
                        len = MAX_PHYSMEM_BITS - page_shift;
                else
                        dev_info(&dev->dev, "Skipping ibm,pmemory");
        }

        if (query.largest_available_block < (1ULL << (len - page_shift))) {
                dev_dbg(&dev->dev,
                        "can't map partition max 0x%llx with %llu %llu-sized pages\n",
                        1ULL << len,
                        query.largest_available_block,
                        1ULL << page_shift);
                goto out_failed;
        }
        win64 = kzalloc(sizeof(struct property), GFP_KERNEL);
        if (!win64) {
                dev_info(&dev->dev,
                        "couldn't allocate property for 64bit dma window\n");
                goto out_failed;
        }
        win64->name = kstrdup(DIRECT64_PROPNAME, GFP_KERNEL);
        win64->value = ddwprop = kmalloc(sizeof(*ddwprop), GFP_KERNEL);
        win64->length = sizeof(*ddwprop);
        if (!win64->name || !win64->value) {
                dev_info(&dev->dev,
                        "couldn't allocate property name and value\n");
                goto out_free_prop;
        }

        ret = create_ddw(dev, ddw_avail, &create, page_shift, len);
        if (ret != 0)
                goto out_free_prop;

        ddwprop->liobn = cpu_to_be32(create.liobn);
        ddwprop->dma_base = cpu_to_be64(((u64)create.addr_hi << 32) |
                        create.addr_lo);
        ddwprop->tce_shift = cpu_to_be32(page_shift);
        ddwprop->window_shift = cpu_to_be32(len);

        dev_dbg(&dev->dev, "created tce table LIOBN 0x%x for %pOF\n",
                  create.liobn, dn);

        window = kzalloc(sizeof(*window), GFP_KERNEL);
        if (!window)
                goto out_clear_window;

        ret = walk_system_ram_range(0, memblock_end_of_DRAM() >> PAGE_SHIFT,
                        win64->value, tce_setrange_multi_pSeriesLP_walk);
        if (ret) {
                dev_info(&dev->dev, "failed to map direct window for %pOF: %d\n",
                         dn, ret);
                goto out_free_window;
        }

        ret = of_add_property(pdn, win64);
        if (ret) {
                dev_err(&dev->dev, "unable to add dma window property for %pOF: %d",
                         pdn, ret);
                goto out_free_window;
        }

        window->device = pdn;
        window->prop = ddwprop;
        spin_lock(&direct_window_list_lock);
        list_add(&window->list, &direct_window_list);
        spin_unlock(&direct_window_list_lock);

        dma_addr = be64_to_cpu(ddwprop->dma_base);
        goto out_unlock;

out_free_window:
        kfree(window);

out_clear_window:
        remove_ddw(pdn, true);

out_free_prop:
        kfree(win64->name);
        kfree(win64->value);
        kfree(win64);

out_failed:
        if (default_win_removed)
                reset_dma_window(dev, pdn);

        fpdn = kzalloc(sizeof(*fpdn), GFP_KERNEL);
        if (!fpdn)
                goto out_unlock;
        fpdn->pdn = pdn;
        list_add(&fpdn->list, &failed_ddw_pdn_list);

out_unlock:
        mutex_unlock(&direct_window_init_mutex);

        /*
         * If we have persistent memory and the window size is only as big
         * as RAM, then we failed to create a window to cover persistent
         * memory and need to set the DMA limit.
         */
        if (pmem_present && dma_addr && (len == max_ram_len))
                dev->dev.bus_dma_limit = dma_addr + (1ULL << len);

        return dma_addr;
}

static void pci_dma_dev_setup_pSeriesLP(struct pci_dev *dev)
{
        struct device_node *pdn, *dn;
        struct iommu_table *tbl;
        const __be32 *dma_window = NULL;
        struct pci_dn *pci;

        pr_debug("pci_dma_dev_setup_pSeriesLP: %s\n", pci_name(dev));

        /* dev setup for LPAR is a little tricky, since the device tree might
         * contain the dma-window properties per-device and not necessarily
         * for the bus. So we need to search upwards in the tree until we
         * either hit a dma-window property, OR find a parent with a table
         * already allocated.
         */
        dn = pci_device_to_OF_node(dev);
        pr_debug("  node is %pOF\n", dn);

        for (pdn = dn; pdn && PCI_DN(pdn) && !PCI_DN(pdn)->table_group;
             pdn = pdn->parent) {
                dma_window = of_get_property(pdn, "ibm,dma-window", NULL);
                if (dma_window)
                        break;
        }

        if (!pdn || !PCI_DN(pdn)) {
                printk(KERN_WARNING "pci_dma_dev_setup_pSeriesLP: "
                       "no DMA window found for pci dev=%s dn=%pOF\n",
                                 pci_name(dev), dn);
                return;
        }
        pr_debug("  parent is %pOF\n", pdn);

        pci = PCI_DN(pdn);
        if (!pci->table_group) {
                pci->table_group = iommu_pseries_alloc_group(pci->phb->node);
                tbl = pci->table_group->tables[0];
                iommu_table_setparms_lpar(pci->phb, pdn, tbl,
                                pci->table_group, dma_window);
                tbl->it_ops = &iommu_table_lpar_multi_ops;
                iommu_init_table(tbl, pci->phb->node, 0, 0);
                iommu_register_group(pci->table_group,
                                pci_domain_nr(pci->phb->bus), 0);
                pr_debug("  created table: %p\n", pci->table_group);
        } else {
                pr_debug("  found DMA window, table: %p\n", pci->table_group);
        }

        set_iommu_table_base(&dev->dev, pci->table_group->tables[0]);
        iommu_add_device(pci->table_group, &dev->dev);
}

static bool iommu_bypass_supported_pSeriesLP(struct pci_dev *pdev, u64 dma_mask)
{
        struct device_node *dn = pci_device_to_OF_node(pdev), *pdn;
        const __be32 *dma_window = NULL;

        /* only attempt to use a new window if 64-bit DMA is requested */
        if (dma_mask < DMA_BIT_MASK(64))
                return false;

        dev_dbg(&pdev->dev, "node is %pOF\n", dn);

        /*
         * the device tree might contain the dma-window properties
         * per-device and not necessarily for the bus. So we need to
         * search upwards in the tree until we either hit a dma-window
         * property, OR find a parent with a table already allocated.
         */
        for (pdn = dn; pdn && PCI_DN(pdn) && !PCI_DN(pdn)->table_group;
                        pdn = pdn->parent) {
                dma_window = of_get_property(pdn, "ibm,dma-window", NULL);
                if (dma_window)
                        break;
        }

        if (pdn && PCI_DN(pdn)) {
                pdev->dev.archdata.dma_offset = enable_ddw(pdev, pdn);
                if (pdev->dev.archdata.dma_offset)
                        return true;
        }

        return false;
}

static int iommu_mem_notifier(struct notifier_block *nb, unsigned long action,
                void *data)
{
        struct direct_window *window;
        struct memory_notify *arg = data;
        int ret = 0;

        switch (action) {
        case MEM_GOING_ONLINE:
                spin_lock(&direct_window_list_lock);
                list_for_each_entry(window, &direct_window_list, list) {
                        ret |= tce_setrange_multi_pSeriesLP(arg->start_pfn,
                                        arg->nr_pages, window->prop);
                        /* XXX log error */
                }
                spin_unlock(&direct_window_list_lock);
                break;
        case MEM_CANCEL_ONLINE:
        case MEM_OFFLINE:
                spin_lock(&direct_window_list_lock);
                list_for_each_entry(window, &direct_window_list, list) {
                        ret |= tce_clearrange_multi_pSeriesLP(arg->start_pfn,
                                        arg->nr_pages, window->prop);
                        /* XXX log error */
                }
                spin_unlock(&direct_window_list_lock);
                break;
        default:
                break;
        }
        if (ret && action != MEM_CANCEL_ONLINE)
                return NOTIFY_BAD;

        return NOTIFY_OK;
}

static struct notifier_block iommu_mem_nb = {
        .notifier_call = iommu_mem_notifier,
};

static int iommu_reconfig_notifier(struct notifier_block *nb, unsigned long action, void *data)
{
        int err = NOTIFY_OK;
        struct of_reconfig_data *rd = data;
        struct device_node *np = rd->dn;
        struct pci_dn *pci = PCI_DN(np);
        struct direct_window *window;

        switch (action) {
        case OF_RECONFIG_DETACH_NODE:
                /*
                 * Removing the property will invoke the reconfig
                 * notifier again, which causes dead-lock on the
                 * read-write semaphore of the notifier chain. So
                 * we have to remove the property when releasing
                 * the device node.
                 */
                remove_ddw(np, false);
                if (pci && pci->table_group)
                        iommu_pseries_free_group(pci->table_group,
                                        np->full_name);

                spin_lock(&direct_window_list_lock);
                list_for_each_entry(window, &direct_window_list, list) {
                        if (window->device == np) {
                                list_del(&window->list);
                                kfree(window);
                                break;
                        }
                }
                spin_unlock(&direct_window_list_lock);
                break;
        default:
                err = NOTIFY_DONE;
                break;
        }
        return err;
}

static struct notifier_block iommu_reconfig_nb = {
        .notifier_call = iommu_reconfig_notifier,
};

/* These are called very early. */
void iommu_init_early_pSeries(void)
{
        if (of_chosen && of_get_property(of_chosen, "linux,iommu-off", NULL))
                return;

        if (firmware_has_feature(FW_FEATURE_LPAR)) {
                pseries_pci_controller_ops.dma_bus_setup = pci_dma_bus_setup_pSeriesLP;
                pseries_pci_controller_ops.dma_dev_setup = pci_dma_dev_setup_pSeriesLP;
                if (!disable_ddw)
                        pseries_pci_controller_ops.iommu_bypass_supported =
                                iommu_bypass_supported_pSeriesLP;
        } else {
                pseries_pci_controller_ops.dma_bus_setup = pci_dma_bus_setup_pSeries;
                pseries_pci_controller_ops.dma_dev_setup = pci_dma_dev_setup_pSeries;
        }


        of_reconfig_notifier_register(&iommu_reconfig_nb);
        register_memory_notifier(&iommu_mem_nb);

        set_pci_dma_ops(&dma_iommu_ops);
}

static int __init disable_multitce(char *str)
{
        if (strcmp(str, "off") == 0 &&
            firmware_has_feature(FW_FEATURE_LPAR) &&
            (firmware_has_feature(FW_FEATURE_PUT_TCE_IND) ||
             firmware_has_feature(FW_FEATURE_STUFF_TCE))) {
                printk(KERN_INFO "Disabling MULTITCE firmware feature\n");
                powerpc_firmware_features &=
                        ~(FW_FEATURE_PUT_TCE_IND | FW_FEATURE_STUFF_TCE);
        }
        return 1;
}

__setup("multitce=", disable_multitce);

static int tce_iommu_bus_notifier(struct notifier_block *nb,
                unsigned long action, void *data)
{
        struct device *dev = data;

        switch (action) {
        case BUS_NOTIFY_DEL_DEVICE:
                iommu_del_device(dev);
                return 0;
        default:
                return 0;
        }
}

static struct notifier_block tce_iommu_bus_nb = {
        .notifier_call = tce_iommu_bus_notifier,
};

static int __init tce_iommu_bus_notifier_init(void)
{
        bus_register_notifier(&pci_bus_type, &tce_iommu_bus_nb);
        return 0;
}
machine_subsys_initcall_sync(pseries, tce_iommu_bus_notifier_init);