/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2013, Nathan Whitehorn <nwhitehorn@FreeBSD.org>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice unmodified, this list of conditions, and the following
 *    disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <sys/param.h>
#include <sys/bus.h>
#include <sys/kernel.h>
#include <sys/libkern.h>
#include <sys/module.h>
#include <sys/vmem.h>

#include <dev/ofw/ofw_bus.h>
#include <dev/ofw/ofw_bus_subr.h>
#include <dev/ofw/openfirm.h>

#include <machine/bus.h>

#include <powerpc/pseries/phyp-hvcall.h>
#include <powerpc/pseries/plpar_iommu.h>

MALLOC_DEFINE(M_PHYPIOMMU, "iommu", "IOMMU data for PAPR LPARs");

struct papr_iommu_map {
        uint32_t iobn;
        vmem_t *vmem;
        struct papr_iommu_map *next;
};

static SLIST_HEAD(iommu_maps, iommu_map) iommu_map_head =
    SLIST_HEAD_INITIALIZER(iommu_map_head);
static int papr_supports_stuff_tce = -1;

struct iommu_map {
        uint32_t iobn;
        vmem_t *vmem;

        SLIST_ENTRY(iommu_map) entries;
};

struct dma_window {
        struct iommu_map *map;
        bus_addr_t start;
        bus_addr_t end;
};

int
phyp_iommu_set_dma_tag(device_t bus, device_t dev, bus_dma_tag_t tag)
{
        device_t p;
        phandle_t node;
        cell_t dma_acells, dma_scells, dmawindow[6];
        struct iommu_map *i;
        int cell;

        for (p = dev; device_get_parent(p) != NULL; p = device_get_parent(p)) {
                if (ofw_bus_has_prop(p, "ibm,my-dma-window"))
                        break;
                if (ofw_bus_has_prop(p, "ibm,dma-window"))
                        break;
        }

        if (p == NULL)
                return (ENXIO);

        node = ofw_bus_get_node(p);
        if (OF_getencprop(node, "ibm,#dma-size-cells", &dma_scells,
            sizeof(cell_t)) <= 0)
                OF_searchencprop(node, "#size-cells", &dma_scells,
                    sizeof(cell_t));
        if (OF_getencprop(node, "ibm,#dma-address-cells", &dma_acells,
            sizeof(cell_t)) <= 0)
                OF_searchencprop(node, "#address-cells", &dma_acells,
                    sizeof(cell_t));

        if (ofw_bus_has_prop(p, "ibm,my-dma-window"))
                OF_getencprop(node, "ibm,my-dma-window", dmawindow,
                    sizeof(cell_t)*(dma_scells + dma_acells + 1));
        else
                OF_getencprop(node, "ibm,dma-window", dmawindow,
                    sizeof(cell_t)*(dma_scells + dma_acells + 1));

        struct dma_window *window = malloc(sizeof(struct dma_window),
            M_PHYPIOMMU, M_WAITOK);
        window->start = 0;
        for (cell = 1; cell < 1 + dma_acells; cell++) {
                window->start <<= 32;
                window->start |= dmawindow[cell];
        }
        window->end = 0;
        for (; cell < 1 + dma_acells + dma_scells; cell++) {
                window->end <<= 32;
                window->end |= dmawindow[cell];
        }
        window->end += window->start;

        if (bootverbose)
                device_printf(dev, "Mapping IOMMU domain %#x\n", dmawindow[0]);
        window->map = NULL;
        SLIST_FOREACH(i, &iommu_map_head, entries) {
                if (i->iobn == dmawindow[0]) {
                        window->map = i;
                        break;
                }
        }

        if (window->map == NULL) {
                window->map = malloc(sizeof(struct iommu_map), M_PHYPIOMMU,
                    M_WAITOK);
                window->map->iobn = dmawindow[0];
                /*
                 * Allocate IOMMU range beginning at PAGE_SIZE. Some drivers
                 * (em(4), for example) do not like getting mappings at 0.
                 */
                window->map->vmem = vmem_create("IOMMU mappings", PAGE_SIZE,
                    trunc_page(VMEM_ADDR_MAX) - PAGE_SIZE, PAGE_SIZE, 0,
                    M_BESTFIT | M_NOWAIT);
                SLIST_INSERT_HEAD(&iommu_map_head, window->map, entries);
        }

        /*
         * Check experimentally whether we can use H_STUFF_TCE. It is required
         * by the spec but some firmware (e.g. QEMU) does not actually support
         * it
         */
        if (papr_supports_stuff_tce == -1)
                papr_supports_stuff_tce = !(phyp_hcall(H_STUFF_TCE,
                    window->map->iobn, 0, 0, 0) == H_FUNCTION);

        bus_dma_tag_set_iommu(tag, bus, window);

        return (0);
}

int
phyp_iommu_map(device_t dev, bus_dma_segment_t *segs, int *nsegs,
    bus_addr_t min, bus_addr_t max, bus_size_t alignment, bus_addr_t boundary,
    void *cookie)
{
        struct dma_window *window = cookie;
        bus_addr_t minaddr, maxaddr;
        bus_addr_t alloced;
        bus_size_t allocsize;
        int error, i, j;
        uint64_t tce;
        minaddr = window->start;
        maxaddr = window->end;

        /* XXX: handle exclusion range in a more useful way */
        if (min < maxaddr)
                maxaddr = min;

        /* XXX: consolidate segs? */
        for (i = 0; i < *nsegs; i++) {
                allocsize = round_page(segs[i].ds_len +
                    (segs[i].ds_addr & PAGE_MASK));
                error = vmem_xalloc(window->map->vmem, allocsize,
                    (alignment < PAGE_SIZE) ? PAGE_SIZE : alignment, 0,
                    boundary, minaddr, maxaddr, M_BESTFIT | M_NOWAIT, &alloced);
                if (error != 0) {
                        panic("VMEM failure: %d\n", error);
                        return (error);
                }
                KASSERT(alloced % PAGE_SIZE == 0, ("Alloc not page aligned"));
                KASSERT((alloced + (segs[i].ds_addr & PAGE_MASK)) %
                    alignment == 0,
                    ("Allocated segment does not match alignment constraint"));

                tce = trunc_page(segs[i].ds_addr);
                tce |= 0x3; /* read/write */
                for (j = 0; j < allocsize; j += PAGE_SIZE) {
                        error = phyp_hcall(H_PUT_TCE, window->map->iobn,
                            alloced + j, tce + j);
                        if (error < 0) {
                                panic("IOMMU mapping error: %d\n", error);
                                return (ENOMEM);
                        }
                }

                segs[i].ds_addr = alloced + (segs[i].ds_addr & PAGE_MASK);
                KASSERT(segs[i].ds_addr > 0, ("Address needs to be positive"));
                KASSERT(segs[i].ds_addr + segs[i].ds_len < maxaddr,
                    ("Address not in range"));
                if (error < 0) {
                        panic("IOMMU mapping error: %d\n", error);
                        return (ENOMEM);
                }
        }

        return (0);
}

int
phyp_iommu_unmap(device_t dev, bus_dma_segment_t *segs, int nsegs, void *cookie)
{
        struct dma_window *window = cookie;
        bus_addr_t pageround;
        bus_size_t roundedsize;
        int i;
        bus_addr_t j;

        for (i = 0; i < nsegs; i++) {
                pageround = trunc_page(segs[i].ds_addr);
                roundedsize = round_page(segs[i].ds_len +
                    (segs[i].ds_addr & PAGE_MASK));

                if (papr_supports_stuff_tce) {
                        phyp_hcall(H_STUFF_TCE, window->map->iobn, pageround, 0,
                            roundedsize/PAGE_SIZE);
                } else {
                        for (j = 0; j < roundedsize; j += PAGE_SIZE)
                                phyp_hcall(H_PUT_TCE, window->map->iobn,
                                    pageround + j, 0);
                }

                vmem_xfree(window->map->vmem, pageround, roundedsize);
        }

        return (0);
}