/* SPDX-License-Identifier: BSD-3-Clause
 * Copyright(c) 2010-2014 Intel Corporation
 */
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");

#include <sys/param.h> /* defines used in kernel.h */
#include <sys/module.h>
#include <sys/kernel.h> /* types used in module initialization */
#include <sys/conf.h> /* cdevsw struct */
#include <sys/bus.h> /* structs, prototypes for pci bus stuff and DEVMETHOD */
#include <sys/rman.h>
#include <sys/systm.h>
#include <sys/lock.h>
#include <sys/rwlock.h>
#include <sys/proc.h>

#include <machine/bus.h>
#include <dev/pci/pcivar.h> /* For pci_get macros! */
#include <dev/pci/pcireg.h> /* The softc holds our per-instance data. */
#include <vm/vm.h>
#include <vm/uma.h>
#include <vm/vm_object.h>
#include <vm/vm_page.h>
#include <vm/vm_pager.h>


#define MAX_BARS (PCIR_MAX_BAR_0 + 1)

#define MAX_DETACHED_DEVICES    128
static device_t detached_devices[MAX_DETACHED_DEVICES] = {};
static int num_detached = 0;

struct nic_uio_softc {
        device_t        dev_t;
        struct cdev     *my_cdev;
        int              bar_id[MAX_BARS];
        struct resource *bar_res[MAX_BARS];
        u_long           bar_start[MAX_BARS];
        u_long           bar_size[MAX_BARS];
};

/* Function prototypes */
static d_open_t         nic_uio_open;
static d_close_t        nic_uio_close;
static d_mmap_t         nic_uio_mmap;
static d_mmap_single_t  nic_uio_mmap_single;
static int              nic_uio_probe(device_t dev);
static int              nic_uio_attach(device_t dev);
static int              nic_uio_detach(device_t dev);
static int              nic_uio_shutdown(void);
static int              nic_uio_modevent(module_t mod, int type, void *arg);

static struct cdevsw uio_cdevsw = {
                .d_name        = "nic_uio",
                .d_version     = D_VERSION,
                .d_open        = nic_uio_open,
                .d_close       = nic_uio_close,
                .d_mmap        = nic_uio_mmap,
                .d_mmap_single = nic_uio_mmap_single,
};

static device_method_t nic_uio_methods[] = {
        DEVMETHOD(device_probe,    nic_uio_probe),
        DEVMETHOD(device_attach,   nic_uio_attach),
        DEVMETHOD(device_detach,   nic_uio_detach),
        DEVMETHOD_END
};

struct device {
    int vend;
    int dev;
};

struct pci_bdf {
        uint32_t bus;
        uint32_t devid;
        uint32_t function;
};

static devclass_t nic_uio_devclass;

DEFINE_CLASS_0(nic_uio, nic_uio_driver, nic_uio_methods, sizeof(struct nic_uio_softc));
DRIVER_MODULE(nic_uio, pci, nic_uio_driver, nic_uio_devclass, nic_uio_modevent, 0);

static int
nic_uio_mmap(struct cdev *cdev, vm_ooffset_t offset, vm_paddr_t *paddr,
                int prot, vm_memattr_t *memattr)
{
        *paddr = offset;
        return 0;
}

static int
nic_uio_mmap_single(struct cdev *cdev, vm_ooffset_t *offset, vm_size_t size,
                struct vm_object **obj, int nprot)
{
        /*
         * The BAR index is encoded in the offset.  Divide the offset by
         *  PAGE_SIZE to get the index of the bar requested by the user
         *  app.
         */
        unsigned bar = *offset/PAGE_SIZE;
        struct nic_uio_softc *sc = cdev->si_drv1;

        if (bar >= MAX_BARS)
                return EINVAL;

        if (sc->bar_res[bar] == NULL) {
                sc->bar_id[bar] = PCIR_BAR(bar);

                if (PCI_BAR_IO(pci_read_config(sc->dev_t, sc->bar_id[bar], 4)))
                        sc->bar_res[bar] = bus_alloc_resource_any(sc->dev_t, SYS_RES_IOPORT,
                                        &sc->bar_id[bar], RF_ACTIVE);
                else
                        sc->bar_res[bar] = bus_alloc_resource_any(sc->dev_t, SYS_RES_MEMORY,
                                        &sc->bar_id[bar], RF_ACTIVE);
        }
        if (sc->bar_res[bar] == NULL)
                return ENXIO;

        sc->bar_start[bar] = rman_get_start(sc->bar_res[bar]);
        sc->bar_size[bar] = rman_get_size(sc->bar_res[bar]);

        device_printf(sc->dev_t, "Bar %u @ %lx, size %lx\n", bar,
                        sc->bar_start[bar], sc->bar_size[bar]);

        *offset = sc->bar_start[bar];
        *obj = vm_pager_allocate(OBJT_DEVICE, cdev, size, nprot, *offset,
                                curthread->td_ucred);
        return 0;
}


int
nic_uio_open(struct cdev *dev, int oflags, int devtype, struct thread *td)
{
        return 0;
}

int
nic_uio_close(struct cdev *dev, int fflag, int devtype, struct thread *td)
{
        return 0;
}

static int
nic_uio_probe (device_t dev)
{
        int i;
        unsigned int bus = pci_get_bus(dev);
        unsigned int device = pci_get_slot(dev);
        unsigned int function = pci_get_function(dev);

        char bdf_str[256];
        char *token, *remaining;

        /* First check if we found this on load */
        for (i = 0; i < num_detached; i++)
                if (bus == pci_get_bus(detached_devices[i]) &&
                    device == pci_get_slot(detached_devices[i]) &&
                    function == pci_get_function(detached_devices[i])) {
                        device_set_desc(dev, "DPDK PCI Device");
                        return BUS_PROBE_SPECIFIC;
                }

        /* otherwise check if it's a new device and if it matches the BDF */
        memset(bdf_str, 0, sizeof(bdf_str));
        TUNABLE_STR_FETCH("hw.nic_uio.bdfs", bdf_str, sizeof(bdf_str));
        remaining = bdf_str;
        while (1) {
                if (remaining == NULL || remaining[0] == '\0')
                        break;
                token = strsep(&remaining, ",:");
                if (token == NULL)
                        break;
                bus = strtol(token, NULL, 10);
                token = strsep(&remaining, ",:");
                if (token == NULL)
                        break;
                device = strtol(token, NULL, 10);
                token = strsep(&remaining, ",:");
                if (token == NULL)
                        break;
                function = strtol(token, NULL, 10);

                if (bus == pci_get_bus(dev) &&
                                device == pci_get_slot(dev) &&
                                function == pci_get_function(dev)) {

                        if (num_detached < MAX_DETACHED_DEVICES) {
                                printf("%s: probed dev=%p\n",
                                               __func__, dev);
                                detached_devices[num_detached++] = dev;
                                device_set_desc(dev, "DPDK PCI Device");
                                return BUS_PROBE_SPECIFIC;
                        } else {
                                printf("%s: reached MAX_DETACHED_DEVICES=%d. dev=%p won't be reattached\n",
                                                __func__, MAX_DETACHED_DEVICES,
                                                dev);
                                break;
                        }
                }
        }

        return ENXIO;
}

static int
nic_uio_attach(device_t dev)
{
        int i;
        struct nic_uio_softc *sc;

        sc = device_get_softc(dev);
        sc->dev_t = dev;
        sc->my_cdev = make_dev(&uio_cdevsw, device_get_unit(dev),
                        UID_ROOT, GID_WHEEL, 0600, "uio@pci:%u:%u:%u",
                        pci_get_bus(dev), pci_get_slot(dev), pci_get_function(dev));
        if (sc->my_cdev == NULL)
                return ENXIO;
        sc->my_cdev->si_drv1 = sc;

        for (i = 0; i < MAX_BARS; i++)
                sc->bar_res[i] = NULL;

        pci_enable_busmaster(dev);

        return 0;
}

static int
nic_uio_detach(device_t dev)
{
        int i;
        struct nic_uio_softc *sc;
        sc = device_get_softc(dev);

        for (i = 0; i < MAX_BARS; i++)
                if (sc->bar_res[i] != NULL) {

                        if (PCI_BAR_IO(pci_read_config(dev, sc->bar_id[i], 4)))
                                bus_release_resource(dev, SYS_RES_IOPORT, sc->bar_id[i],
                                                sc->bar_res[i]);
                        else
                                bus_release_resource(dev, SYS_RES_MEMORY, sc->bar_id[i],
                                                sc->bar_res[i]);
                }

        if (sc->my_cdev != NULL)
                destroy_dev(sc->my_cdev);
        return 0;
}

static void
nic_uio_load(void)
{
        uint32_t bus, device, function;
        device_t dev;
        char bdf_str[256];
        char *token, *remaining;

        memset(bdf_str, 0, sizeof(bdf_str));
        TUNABLE_STR_FETCH("hw.nic_uio.bdfs", bdf_str, sizeof(bdf_str));
        remaining = bdf_str;
        printf("nic_uio: hw.nic_uio.bdfs = '%s'\n", bdf_str);
        /*
         * Users should specify PCI BDFs in the format "b:d:f,b:d:f,b:d:f".
         *  But the code below does not try differentiate between : and ,
         *  and just blindly uses 3 tokens at a time to construct a
         *  bus/device/function tuple.
         *
         * There is no checking on strtol() return values, but this should
         *  be OK.  Worst case is it cannot convert and returns 0.  This
         *  could give us a different BDF than intended, but as long as the
         *  PCI device/vendor ID does not match it will not matter.
         */
        while (1) {
                if (remaining == NULL || remaining[0] == '\0')
                        break;
                token = strsep(&remaining, ",:");
                if (token == NULL)
                        break;
                bus = strtol(token, NULL, 10);
                token = strsep(&remaining, ",:");
                if (token == NULL)
                        break;
                device = strtol(token, NULL, 10);
                token = strsep(&remaining, ",:");
                if (token == NULL)
                        break;
                function = strtol(token, NULL, 10);

                dev = pci_find_bsf(bus, device, function);
                if (dev == NULL)
                        continue;

                if (num_detached < MAX_DETACHED_DEVICES) {
                        printf("nic_uio_load: detaching and storing dev=%p\n",
                               dev);
                        detached_devices[num_detached++] = dev;
                } else {
                        printf("nic_uio_load: reached MAX_DETACHED_DEVICES=%d. dev=%p won't be reattached\n",
                               MAX_DETACHED_DEVICES, dev);
                }
                device_detach(dev);
        }
}

static void
nic_uio_unload(void)
{
        int i;
        printf("nic_uio_unload: entered...\n");

        for (i = 0; i < num_detached; i++) {
                printf("nic_uio_unload: calling to device_probe_and_attach for dev=%p...\n",
                        detached_devices[i]);
                device_probe_and_attach(detached_devices[i]);
                printf("nic_uio_unload: done.\n");
        }

        printf("nic_uio_unload: leaving...\n");
}

static int
nic_uio_shutdown(void)
{
        return 0;
}

static int
nic_uio_modevent(module_t mod, int type, void *arg)
{

        switch (type) {
        case MOD_LOAD:
                nic_uio_load();
                break;
        case MOD_UNLOAD:
                nic_uio_unload();
                break;
        case MOD_SHUTDOWN:
                nic_uio_shutdown();
                break;
        default:
                break;
        }

        return 0;
}