/*
 * 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.
 *
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
 */

#include <linux/init.h>
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/mm.h>
#include <linux/spinlock.h>
#include <linux/string.h>
#include <linux/pci.h>
#include <linux/dma-mapping.h>
#include <linux/crash_dump.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/abs_addr.h>
#include <asm/pSeries_reconfig.h>
#include <asm/firmware.h>
#include <asm/tce.h>
#include <asm/ppc-pci.h>
#include <asm/udbg.h>

#include "plpar_wrappers.h"


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

        proto_tce = TCE_PCI_READ; // Read allowed

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

        tcep = ((u64 *)tbl->it_base) + index;

        while (npages--) {
                /* can't move this out since we might cross LMB boundary */
                rpn = (virt_to_abs(uaddr)) >> TCE_SHIFT;
                *tcep = 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)
{
        u64 *tcep;

        tcep = ((u64 *)tbl->it_base) + index;

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

static unsigned long tce_get_pseries(struct iommu_table *tbl, long index)
{
        u64 *tcep;

        tcep = ((u64 *)tbl->it_base) + index;

        return *tcep;
}

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

static int tce_build_pSeriesLP(struct iommu_table *tbl, long tcenum,
                                long npages, unsigned long uaddr,
                                enum dma_data_direction direction,
                                struct dma_attrs *attrs)
{
        u64 rc = 0;
        u64 proto_tce, tce;
        u64 rpn;
        int ret = 0;
        long tcenum_start = tcenum, npages_start = npages;

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

        while (npages--) {
                tce = proto_tce | (rpn & TCE_RPN_MASK) << TCE_RPN_SHIFT;
                rc = plpar_tce_put((u64)tbl->it_index, (u64)tcenum << 12, tce);

                if (unlikely(rc == H_NOT_ENOUGH_RESOURCES)) {
                        ret = (int)rc;
                        tce_free_pSeriesLP(tbl, 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)tbl->it_index);
                        printk("\ttcenum  = 0x%llx\n", (u64)tcenum);
                        printk("\ttce val = 0x%llx\n", tce );
                        show_stack(current, (unsigned long *)__get_SP());
                }

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

static DEFINE_PER_CPU(u64 *, tce_page) = NULL;

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

        if (npages == 1) {
                return tce_build_pSeriesLP(tbl, tcenum, npages, uaddr,
                                           direction, attrs);
        }

        tcep = __get_cpu_var(tce_page);

        /* This is safe to do since interrupts are off when we're called
         * from iommu_alloc{,_sg}()
         */
        if (!tcep) {
                tcep = (u64 *)__get_free_page(GFP_ATOMIC);
                /* If allocation fails, fall back to the loop implementation */
                if (!tcep) {
                        return tce_build_pSeriesLP(tbl, tcenum, npages, uaddr,
                                            direction, attrs);
                }
                __get_cpu_var(tce_page) = tcep;
        }

        rpn = (virt_to_abs(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] = proto_tce | (rpn & TCE_RPN_MASK) << TCE_RPN_SHIFT;
                        rpn++;
                }

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

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

        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]);
                show_stack(current, (unsigned long *)__get_SP());
        }
        return ret;
}

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

        while (npages--) {
                rc = plpar_tce_put((u64)tbl->it_index, (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)tbl->it_index);
                        printk("\ttcenum  = 0x%llx\n", (u64)tcenum);
                        show_stack(current, (unsigned long *)__get_SP());
                }

                tcenum++;
        }
}


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

        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);
                show_stack(current, (unsigned long *)__get_SP());
        }
}

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);
                show_stack(current, (unsigned long *)__get_SP());
        }

        return tce_ret;
}

#ifdef CONFIG_PCI
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: %s has "
                                "missing tce entries !\n", dn->full_name);
                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;

        /* Units of tce entries */
        tbl->it_offset = phb->dma_window_base_cur >> IOMMU_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 >> IOMMU_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,
                                      const void *dma_window,
                                      int bussubno)
{
        unsigned long offset, size;

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

        tbl->it_base   = 0;
        tbl->it_blocksize  = 16;
        tbl->it_type = TCE_PCI;
        tbl->it_offset = offset >> IOMMU_PAGE_SHIFT;
        tbl->it_size = size >> IOMMU_PAGE_SHIFT;
}

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 %s\n", dn->full_name);

        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;

        if (isa_dn_orig)
                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;

        tbl = kmalloc_node(sizeof(struct iommu_table), GFP_KERNEL,
                           pci->phb->node);

        iommu_table_setparms(pci->phb, dn, tbl);
        pci->iommu_table = iommu_init_table(tbl, pci->phb->node);

        /* 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);
}


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 void *dma_window = NULL;

        dn = pci_bus_to_OF_node(bus);

        pr_debug("pci_dma_bus_setup_pSeriesLP: setting up bus %s\n",
                 dn->full_name);

        /* 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 %s, iommu_table: 0x%p\n",
                 pdn->full_name, ppci->iommu_table);

        if (!ppci->iommu_table) {
                tbl = kmalloc_node(sizeof(struct iommu_table), GFP_KERNEL,
                                   ppci->phb->node);
                iommu_table_setparms_lpar(ppci->phb, pdn, tbl, dma_window,
                        bus->number);
                ppci->iommu_table = iommu_init_table(tbl, ppci->phb->node);
                pr_debug("  created table: %p\n", ppci->iommu_table);
        }

        if (pdn != dn)
                PCI_DN(dn)->iommu_table = ppci->iommu_table;
}


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.archdata.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");
                tbl = kmalloc_node(sizeof(struct iommu_table), GFP_KERNEL,
                                   phb->node);
                iommu_table_setparms(phb, dn, tbl);
                PCI_DN(dn)->iommu_table = iommu_init_table(tbl, phb->node);
                set_iommu_table_base(&dev->dev, PCI_DN(dn)->iommu_table);
                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)->iommu_table == NULL)
                dn = dn->parent;

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

static void pci_dma_dev_setup_pSeriesLP(struct pci_dev *dev)
{
        struct device_node *pdn, *dn;
        struct iommu_table *tbl;
        const void *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 neccesarily
         * 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 %s\n", dn->full_name);

        for (pdn = dn; pdn && PCI_DN(pdn) && !PCI_DN(pdn)->iommu_table;
             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=%s\n",
                                 pci_name(dev), dn? dn->full_name : "<null>");
                return;
        }
        pr_debug("  parent is %s\n", pdn->full_name);

        /* Check for parent == NULL so we don't try to setup the empty EADS
         * slots on POWER4 machines.
         */
        if (dma_window == NULL || pdn->parent == NULL) {
                pr_debug("  no dma window for device, linking to parent\n");
                set_iommu_table_base(&dev->dev, PCI_DN(pdn)->iommu_table);
                return;
        }

        pci = PCI_DN(pdn);
        if (!pci->iommu_table) {
                tbl = kmalloc_node(sizeof(struct iommu_table), GFP_KERNEL,
                                   pci->phb->node);
                iommu_table_setparms_lpar(pci->phb, pdn, tbl, dma_window,
                        pci->phb->bus->number);
                pci->iommu_table = iommu_init_table(tbl, pci->phb->node);
                pr_debug("  created table: %p\n", pci->iommu_table);
        } else {
                pr_debug("  found DMA window, table: %p\n", pci->iommu_table);
        }

        set_iommu_table_base(&dev->dev, pci->iommu_table);
}
#else  /* CONFIG_PCI */
#define pci_dma_bus_setup_pSeries       NULL
#define pci_dma_dev_setup_pSeries       NULL
#define pci_dma_bus_setup_pSeriesLP     NULL
#define pci_dma_dev_setup_pSeriesLP     NULL
#endif /* !CONFIG_PCI */

static int iommu_reconfig_notifier(struct notifier_block *nb, unsigned long action, void *node)
{
        int err = NOTIFY_OK;
        struct device_node *np = node;
        struct pci_dn *pci = PCI_DN(np);

        switch (action) {
        case PSERIES_RECONFIG_REMOVE:
                if (pci && pci->iommu_table &&
                    of_get_property(np, "ibm,dma-window", NULL))
                        iommu_free_table(pci->iommu_table, np->full_name);
                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)) {
                /* Direct I/O, IOMMU off */
                ppc_md.pci_dma_dev_setup = NULL;
                ppc_md.pci_dma_bus_setup = NULL;
                set_pci_dma_ops(&dma_direct_ops);
                return;
        }

        if (firmware_has_feature(FW_FEATURE_LPAR)) {
                if (firmware_has_feature(FW_FEATURE_MULTITCE)) {
                        ppc_md.tce_build = tce_buildmulti_pSeriesLP;
                        ppc_md.tce_free  = tce_freemulti_pSeriesLP;
                } else {
                        ppc_md.tce_build = tce_build_pSeriesLP;
                        ppc_md.tce_free  = tce_free_pSeriesLP;
                }
                ppc_md.tce_get   = tce_get_pSeriesLP;
                ppc_md.pci_dma_bus_setup = pci_dma_bus_setup_pSeriesLP;
                ppc_md.pci_dma_dev_setup = pci_dma_dev_setup_pSeriesLP;
        } else {
                ppc_md.tce_build = tce_build_pSeries;
                ppc_md.tce_free  = tce_free_pSeries;
                ppc_md.tce_get   = tce_get_pseries;
                ppc_md.pci_dma_bus_setup = pci_dma_bus_setup_pSeries;
                ppc_md.pci_dma_dev_setup = pci_dma_dev_setup_pSeries;
        }


        pSeries_reconfig_notifier_register(&iommu_reconfig_nb);

        set_pci_dma_ops(&dma_iommu_ops);
}