/* $NetBSD: ld_virtio.c,v 1.44 2025/07/05 11:41:13 mlelstv Exp $ */

/* $NetBSD: ld_virtio.c,v 1.44 2025/07/05 11:41:13 mlelstv Exp $ */

/*
* Copyright (c) 2010 Minoura Makoto.
* 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, 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/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: ld_virtio.c,v 1.44 2025/07/05 11:41:13 mlelstv Exp $");

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/buf.h>
#include <sys/bufq.h>
#include <sys/bus.h>
#include <sys/device.h>
#include <sys/disk.h>
#include <sys/mutex.h>
#include <sys/module.h>
#include <sys/kmem.h>

#include <dev/ldvar.h>
#include <dev/pci/virtioreg.h>
#include <dev/pci/virtiovar.h>

#include "ioconf.h"

/*
* ld_virtioreg:
*/
/* Configuration registers */
#define VIRTIO_BLK_CONFIG_CAPACITY 0 /* 64bit */
#define VIRTIO_BLK_CONFIG_SIZE_MAX 8 /* 32bit */
#define VIRTIO_BLK_CONFIG_SEG_MAX 12 /* 32bit */
#define VIRTIO_BLK_CONFIG_GEOMETRY_C 16 /* 16bit */
#define VIRTIO_BLK_CONFIG_GEOMETRY_H 18 /* 8bit */
#define VIRTIO_BLK_CONFIG_GEOMETRY_S 19 /* 8bit */
#define VIRTIO_BLK_CONFIG_BLK_SIZE 20 /* 32bit */
#define VIRTIO_BLK_CONFIG_PHYSICAL_BLOCK_EXP 24 /* 8bit */
#define VIRTIO_BLK_CONFIG_ALIGNMENT_OFFSET 25 /* 8bit */
#define VIRTIO_BLK_CONFIG_MIN_IO_SIZE 26 /* 16bit */
#define VIRTIO_BLK_CONFIG_OPT_IO_SIZE 28 /* 32bit */
#define VIRTIO_BLK_CONFIG_WRITEBACK 32 /* 8bit */
#define VIRTIO_BLK_CONFIG_NUM_QUEUES 34 /* 16bit */
#define VIRTIO_BLK_CONFIG_MAX_DISCARD_SECTORS 36 /* 32bit */
#define VIRTIO_BLK_CONFIG_MAX_DISCARD_SEG 40 /* 32bit */
#define VIRTIO_BLK_CONFIG_DISCARD_SECTOR_ALIGNMENT 44 /* 32bit */

/* Feature bits */
#define VIRTIO_BLK_F_BARRIER (1<<0)
#define VIRTIO_BLK_F_SIZE_MAX (1<<1)
#define VIRTIO_BLK_F_SEG_MAX (1<<2)
#define VIRTIO_BLK_F_GEOMETRY (1<<4)
#define VIRTIO_BLK_F_RO (1<<5)
#define VIRTIO_BLK_F_BLK_SIZE (1<<6)
#define VIRTIO_BLK_F_SCSI (1<<7)
#define VIRTIO_BLK_F_FLUSH (1<<9)
#define VIRTIO_BLK_F_TOPOLOGY (1<<10)
#define VIRTIO_BLK_F_CONFIG_WCE (1<<11)
#define VIRTIO_BLK_F_MQ (1<<12)
#define VIRTIO_BLK_F_DISCARD (1<<13)
#define VIRTIO_BLK_F_WRITE_ZEROES (1<<14)
#define VIRTIO_BLK_F_LIFETIME (1<<15)
#define VIRTIO_BLK_F_SECURE_ERASE (1<<16)

/*
* Each block request uses at least two segments - one for the header
* and one for the status.
*/
#define VIRTIO_BLK_CTRL_SEGMENTS 2

#define VIRTIO_BLK_FLAG_BITS \
VIRTIO_COMMON_FLAG_BITS \
"b\x10" "SECURE_ERASE\0" \
"b\x0f" "LIFETIME\0" \
"b\x0e" "WRITE_ZEROES\0" \
"b\x0d" "DISCARD\0" \
"b\x0c" "MQ\0" \
"b\x0b" "CONFIG_WCE\0" \
"b\x0a" "TOPOLOGY\0" \
"b\x09" "FLUSH\0" \
"b\x07" "SCSI\0" \
"b\x06" "BLK_SIZE\0" \
"b\x05" "RO\0" \
"b\x04" "GEOMETRY\0" \
"b\x02" "SEG_MAX\0" \
"b\x01" "SIZE_MAX\0" \
"b\x00" "BARRIER\0"

/* Command */
#define VIRTIO_BLK_T_IN 0
#define VIRTIO_BLK_T_OUT 1
#define VIRTIO_BLK_T_FLUSH 4
#define VIRTIO_BLK_T_GET_ID 8
#define VIRTIO_BLK_T_GET_LIFETIME 10
#define VIRTIO_BLK_T_DISCARD 11
#define VIRTIO_BLK_T_WRITE_ZEROES 13
#define VIRTIO_BLK_T_SECURE_ERASE 14
#define VIRTIO_BLK_T_BARRIER 0x80000000

/* Sector */
#define VIRTIO_BLK_BSIZE 512

/* Status */
#define VIRTIO_BLK_S_OK 0
#define VIRTIO_BLK_S_IOERR 1
#define VIRTIO_BLK_S_UNSUPP 2

/* Request header structure */
struct virtio_blk_req_hdr {
uint32_t type; /* VIRTIO_BLK_T_* */
uint32_t ioprio;
uint64_t sector;
} __packed;
/* payload and 1 byte status follows */

struct virtio_blk_discard_write_zeroes {
uint64_t sector;
uint32_t num_sectors;
union {
uint32_t flags;
struct {
uint32_t unmap:1;
uint32_t reserved:31;
};
};
} __packed;

/*
* ld_virtiovar:
*/
struct virtio_blk_req {
struct virtio_blk_req_hdr vr_hdr;
uint8_t vr_status;
struct buf *vr_bp;
#define DUMMY_VR_BP ((void *)1)
bus_dmamap_t vr_cmdsts;
bus_dmamap_t vr_payload;
void * vr_datap;
size_t vr_datas;
};

struct ld_virtio_softc {
struct ld_softc sc_ld;
device_t sc_dev;

uint32_t sc_seg_max; /* max number of segs in xfer */
uint32_t sc_size_max; /* max size of single seg */

struct virtio_softc *sc_virtio;
struct virtqueue sc_vq;

struct virtio_blk_req *sc_reqs;
bus_dma_segment_t sc_reqs_seg;

int sc_readonly;

enum {
SYNC_FREE, SYNC_BUSY, SYNC_DONE
} sc_sync_use;
kcondvar_t sc_sync_wait;
kmutex_t sc_sync_wait_lock;
uint8_t sc_sync_status;
uint8_t *sc_typename;

uint32_t sc_max_discard_sectors;
uint32_t sc_max_discard_seg;
#if 0
uint32_t sc_discard_sector_alignment;
#endif
};

static int ld_virtio_match(device_t, cfdata_t, void *);
static void ld_virtio_attach(device_t, device_t, void *);
static int ld_virtio_detach(device_t, int);

CFATTACH_DECL_NEW(ld_virtio, sizeof(struct ld_virtio_softc),
ld_virtio_match, ld_virtio_attach, ld_virtio_detach, NULL);

static int
ld_virtio_match(device_t parent, cfdata_t match, void *aux)
{
struct virtio_attach_args *va = aux;

if (va->sc_childdevid == VIRTIO_DEVICE_ID_BLOCK)
return 1;

return 0;
}

static int ld_virtio_vq_done(struct virtqueue *);
static int ld_virtio_dump(struct ld_softc *, void *, daddr_t, int);
static int ld_virtio_start(struct ld_softc *, struct buf *);
static int ld_virtio_ioctl(struct ld_softc *, u_long, void *, int32_t, bool);
static int ld_virtio_info(struct ld_softc *, bool);
static int ld_virtio_discard(struct ld_softc *, struct buf *);

static int
ld_virtio_alloc_reqs(struct ld_virtio_softc *sc, int qsize)
{
int allocsize, r, rsegs, i;
struct ld_softc *ld = &sc->sc_ld;
void *vaddr;

allocsize = sizeof(struct virtio_blk_req) * qsize;
r = bus_dmamem_alloc(virtio_dmat(sc->sc_virtio), allocsize, 0, 0,
&sc->sc_reqs_seg, 1, &rsegs, BUS_DMA_WAITOK);
if (r != 0) {
aprint_error_dev(sc->sc_dev,
"DMA memory allocation failed, size %d, "
"error code %d\n", allocsize, r);
goto err_none;
}
r = bus_dmamem_map(virtio_dmat(sc->sc_virtio),
&sc->sc_reqs_seg, 1, allocsize,
&vaddr, BUS_DMA_WAITOK);
if (r != 0) {
aprint_error_dev(sc->sc_dev,
"DMA memory map failed, "
"error code %d\n", r);
goto err_dmamem_alloc;
}
sc->sc_reqs = vaddr;
memset(vaddr, 0, allocsize);
for (i = 0; i < qsize; i++) {
struct virtio_blk_req *vr = &sc->sc_reqs[i];
r = bus_dmamap_create(virtio_dmat(sc->sc_virtio),
offsetof(struct virtio_blk_req, vr_bp),
1,
offsetof(struct virtio_blk_req, vr_bp),
0,
BUS_DMA_WAITOK|BUS_DMA_ALLOCNOW,
&vr->vr_cmdsts);
if (r != 0) {
aprint_error_dev(sc->sc_dev,
"command dmamap creation failed, "
"error code %d\n", r);
goto err_reqs;
}
r = bus_dmamap_load(virtio_dmat(sc->sc_virtio), vr->vr_cmdsts,
&vr->vr_hdr,
offsetof(struct virtio_blk_req, vr_bp),
NULL, BUS_DMA_WAITOK);
if (r != 0) {
aprint_error_dev(sc->sc_dev,
"command dmamap load failed, "
"error code %d\n", r);
goto err_reqs;
}
r = bus_dmamap_create(virtio_dmat(sc->sc_virtio),
/*size*/ld->sc_maxxfer,
/*nseg*/sc->sc_seg_max,
/*maxsegsz*/sc->sc_size_max,
/*boundary*/0,
BUS_DMA_WAITOK|BUS_DMA_ALLOCNOW,
&vr->vr_payload);
if (r != 0) {
aprint_error_dev(sc->sc_dev,
"payload dmamap creation failed, "
"error code %d\n", r);
goto err_reqs;
}
vr->vr_datap = NULL;
vr->vr_datas = 0;
}
return 0;

err_reqs:
for (i = 0; i < qsize; i++) {
struct virtio_blk_req *vr = &sc->sc_reqs[i];
if (vr->vr_cmdsts) {
bus_dmamap_destroy(virtio_dmat(sc->sc_virtio),
vr->vr_cmdsts);
vr->vr_cmdsts = 0;
}
if (vr->vr_payload) {
bus_dmamap_destroy(virtio_dmat(sc->sc_virtio),
vr->vr_payload);
vr->vr_payload = 0;
}
}
bus_dmamem_unmap(virtio_dmat(sc->sc_virtio), sc->sc_reqs, allocsize);
err_dmamem_alloc:
bus_dmamem_free(virtio_dmat(sc->sc_virtio), &sc->sc_reqs_seg, 1);
err_none:
return -1;
}

static void
ld_virtio_attach(device_t parent, device_t self, void *aux)
{
struct ld_virtio_softc *sc = device_private(self);
struct ld_softc *ld = &sc->sc_ld;
struct virtio_softc *vsc = device_private(parent);
uint64_t features;
int qsize;

if (virtio_child(vsc) != NULL) {
aprint_normal(": child already attached for %s; "
"something wrong...\n", device_xname(parent));
return;
}

sc->sc_dev = self;
sc->sc_virtio = vsc;

virtio_child_attach_start(vsc, self, IPL_BIO,
(VIRTIO_BLK_F_SIZE_MAX | VIRTIO_BLK_F_SEG_MAX |
VIRTIO_BLK_F_GEOMETRY | VIRTIO_BLK_F_RO | VIRTIO_BLK_F_BLK_SIZE |
VIRTIO_BLK_F_FLUSH | VIRTIO_BLK_F_TOPOLOGY |
VIRTIO_BLK_F_CONFIG_WCE | VIRTIO_BLK_F_DISCARD),
VIRTIO_BLK_FLAG_BITS);

features = virtio_features(vsc);
if (features == 0)
goto err;

if (features & VIRTIO_BLK_F_RO)
sc->sc_readonly = 1;
else
sc->sc_readonly = 0;

if (features & VIRTIO_BLK_F_BLK_SIZE) {
ld->sc_secsize = virtio_read_device_config_4(vsc,
VIRTIO_BLK_CONFIG_BLK_SIZE);
} else
ld->sc_secsize = VIRTIO_BLK_BSIZE;

if (features & VIRTIO_BLK_F_SEG_MAX) {
sc->sc_seg_max = virtio_read_device_config_4(vsc,
VIRTIO_BLK_CONFIG_SEG_MAX);
if (sc->sc_seg_max == 0) {
aprint_error_dev(sc->sc_dev,
"Invalid SEG_MAX %d\n", sc->sc_seg_max);
goto err;
}
} else {
sc->sc_seg_max = 1;
aprint_verbose_dev(sc->sc_dev,
"Unknown SEG_MAX, assuming %"PRIu32"\n", sc->sc_seg_max);
}

/* At least genfs_io assumes size_max*seg_max >= MAXPHYS. */
if (features & VIRTIO_BLK_F_SIZE_MAX) {
sc->sc_size_max = virtio_read_device_config_4(vsc,
VIRTIO_BLK_CONFIG_SIZE_MAX);
if (sc->sc_size_max < MAXPHYS/sc->sc_seg_max) {
aprint_error_dev(sc->sc_dev,
"Too small SIZE_MAX %d minimum is %d\n",
sc->sc_size_max, MAXPHYS/sc->sc_seg_max);
// goto err;
sc->sc_size_max = MAXPHYS/sc->sc_seg_max;
} else if (sc->sc_size_max > MAXPHYS) {
aprint_verbose_dev(sc->sc_dev,
"Clip SIZE_MAX from %d to %d\n",
sc->sc_size_max, MAXPHYS);
sc->sc_size_max = MAXPHYS;
}
} else {
sc->sc_size_max = MAXPHYS;
aprint_verbose_dev(sc->sc_dev,
"Unknown SIZE_MAX, assuming %"PRIu32"\n",
sc->sc_size_max);
}

aprint_normal_dev(sc->sc_dev, "max %"PRIu32" segs"
" of max %"PRIu32" bytes\n",
sc->sc_seg_max, sc->sc_size_max);

virtio_init_vq_vqdone(vsc, &sc->sc_vq, 0,
ld_virtio_vq_done);

if (virtio_alloc_vq(vsc, &sc->sc_vq, sc->sc_size_max,
sc->sc_seg_max + VIRTIO_BLK_CTRL_SEGMENTS, "I/O request") != 0)
goto err;
qsize = sc->sc_vq.vq_num;

if (virtio_child_attach_finish(vsc, &sc->sc_vq, 1,
NULL, VIRTIO_F_INTR_MSIX) != 0)
goto err;

ld->sc_dv = self;
ld->sc_secperunit = virtio_read_device_config_8(vsc,
VIRTIO_BLK_CONFIG_CAPACITY) / (ld->sc_secsize / VIRTIO_BLK_BSIZE);

/*
* Clamp ld->sc_maxxfer to MAXPHYS before ld_virtio_alloc_reqs
* allocates DMA maps of at most ld->sc_maxxfer bytes.
* ldattach will also clamp to MAXPHYS, but not until after
* ld_virtio_alloc_reqs is done, so that doesn't help.
*/
ld->sc_maxxfer = MIN(MAXPHYS, sc->sc_size_max * sc->sc_seg_max);

if (features & VIRTIO_BLK_F_GEOMETRY) {
ld->sc_ncylinders = virtio_read_device_config_2(vsc,
VIRTIO_BLK_CONFIG_GEOMETRY_C);
ld->sc_nheads = virtio_read_device_config_1(vsc,
VIRTIO_BLK_CONFIG_GEOMETRY_H);
ld->sc_nsectors = virtio_read_device_config_1(vsc,
VIRTIO_BLK_CONFIG_GEOMETRY_S);
}
if (features & VIRTIO_BLK_F_TOPOLOGY) {
ld->sc_alignedsec = virtio_read_device_config_1(vsc,
VIRTIO_BLK_CONFIG_ALIGNMENT_OFFSET);
ld->sc_physsecsize = ld->sc_secsize <<
virtio_read_device_config_1(vsc,
VIRTIO_BLK_CONFIG_PHYSICAL_BLOCK_EXP);
}
ld->sc_maxqueuecnt = qsize - 1; /* reserve slot for dumps, flushes */

if (ld_virtio_alloc_reqs(sc, qsize) < 0)
goto err;

cv_init(&sc->sc_sync_wait, "vblksync");
mutex_init(&sc->sc_sync_wait_lock, MUTEX_DEFAULT, IPL_BIO);
sc->sc_sync_use = SYNC_FREE;

ld->sc_dump = ld_virtio_dump;
ld->sc_start = ld_virtio_start;
ld->sc_ioctl = ld_virtio_ioctl;

if (ld_virtio_info(ld, true) == 0)
ld->sc_typename = sc->sc_typename;
else
ld->sc_typename = __UNCONST("Virtio Block Device");

if (features & VIRTIO_BLK_F_DISCARD) {
ld->sc_discard = ld_virtio_discard;
sc->sc_max_discard_sectors = virtio_read_device_config_4(vsc,
VIRTIO_BLK_CONFIG_MAX_DISCARD_SECTORS);
sc->sc_max_discard_seg = virtio_read_device_config_4(vsc,
VIRTIO_BLK_CONFIG_MAX_DISCARD_SEG);
#if 0
sc->sc_discard_sector_alignment =
virtio_read_device_config_4(vsc,
VIRTIO_BLK_CONFIG_DISCARD_SECTOR_ALIGNMENT);
#endif
}

ld->sc_flags = LDF_ENABLED | LDF_MPSAFE;
ldattach(ld, BUFQ_DISK_DEFAULT_STRAT);

return;

err:
virtio_child_attach_failed(vsc);
return;
}

static int __used
ld_virtio_info(struct ld_softc *ld, bool poll)
{
struct ld_virtio_softc *sc = device_private(ld->sc_dv);
struct virtio_softc *vsc = sc->sc_virtio;
struct virtqueue *vq = &sc->sc_vq;
struct virtio_blk_req *vr;
int r;
int slot;
uint8_t *id_data; /* virtio v1.2 5.2.6 */
size_t id_len = 20;
bool unload = false;

if (sc->sc_typename != NULL) {
kmem_strfree(sc->sc_typename);
sc->sc_typename = NULL;
}

id_data = kmem_alloc(id_len, KM_SLEEP);

mutex_enter(&sc->sc_sync_wait_lock);
while (sc->sc_sync_use != SYNC_FREE) {
if (poll) {
mutex_exit(&sc->sc_sync_wait_lock);
ld_virtio_vq_done(vq);
mutex_enter(&sc->sc_sync_wait_lock);
continue;
}
cv_wait(&sc->sc_sync_wait, &sc->sc_sync_wait_lock);
}
sc->sc_sync_use = SYNC_BUSY;
mutex_exit(&sc->sc_sync_wait_lock);

r = virtio_enqueue_prep(vsc, vq, &slot);
if (r != 0)
goto done;

vr = &sc->sc_reqs[slot];
KASSERT(vr->vr_bp == NULL);

r = bus_dmamap_load(virtio_dmat(vsc), vr->vr_payload,
id_data, id_len, NULL,
BUS_DMA_READ|BUS_DMA_NOWAIT);
if (r != 0) {
aprint_error_dev(sc->sc_dev,
"payload dmamap failed, error code %d\n", r);
virtio_enqueue_abort(vsc, vq, slot);
goto done;
}
unload = true;

KASSERT(vr->vr_payload->dm_nsegs <= sc->sc_seg_max);
r = virtio_enqueue_reserve(vsc, vq, slot, vr->vr_payload->dm_nsegs +
VIRTIO_BLK_CTRL_SEGMENTS);
if (r != 0) {
bus_dmamap_unload(virtio_dmat(vsc), vr->vr_payload);
goto done;
}

vr->vr_bp = DUMMY_VR_BP;
vr->vr_hdr.type = virtio_rw32(vsc, VIRTIO_BLK_T_GET_ID);
vr->vr_hdr.ioprio = virtio_rw32(vsc, 0);
vr->vr_hdr.sector = virtio_rw64(vsc, 0);

bus_dmamap_sync(virtio_dmat(vsc), vr->vr_cmdsts,
0, sizeof(struct virtio_blk_req_hdr),
BUS_DMASYNC_PREWRITE);
bus_dmamap_sync(virtio_dmat(vsc), vr->vr_payload,
0, id_len,
BUS_DMASYNC_PREREAD);
bus_dmamap_sync(virtio_dmat(vsc), vr->vr_cmdsts,
offsetof(struct virtio_blk_req, vr_status),
sizeof(uint8_t),
BUS_DMASYNC_PREREAD);

virtio_enqueue_p(vsc, vq, slot, vr->vr_cmdsts,
0, sizeof(struct virtio_blk_req_hdr),
true);
virtio_enqueue(vsc, vq, slot, vr->vr_payload, false);
virtio_enqueue_p(vsc, vq, slot, vr->vr_cmdsts,
offsetof(struct virtio_blk_req, vr_status),
sizeof(uint8_t),
false);
virtio_enqueue_commit(vsc, vq, slot, true);

done:
mutex_enter(&sc->sc_sync_wait_lock);
while (sc->sc_sync_use != SYNC_DONE) {
if (poll) {
mutex_exit(&sc->sc_sync_wait_lock);
ld_virtio_vq_done(vq);
mutex_enter(&sc->sc_sync_wait_lock);
continue;
}
cv_wait(&sc->sc_sync_wait, &sc->sc_sync_wait_lock);
}

if (sc->sc_sync_status == VIRTIO_BLK_S_OK)
r = 0;
else
r = EIO;

sc->sc_sync_use = SYNC_FREE;
cv_broadcast(&sc->sc_sync_wait);
mutex_exit(&sc->sc_sync_wait_lock);

if (unload) {
bus_dmamap_sync(virtio_dmat(vsc), vr->vr_payload,
0, id_len, BUS_DMASYNC_POSTREAD);
bus_dmamap_unload(virtio_dmat(vsc), vr->vr_payload);
}

if (r == 0) {
if (id_data[0] == '\0')
r = ENOENT;
else
sc->sc_typename = kmem_strndup(id_data, sizeof(id_data), KM_NOSLEEP);
}

kmem_free(id_data, id_len);

return r;
}

static int
ld_virtio_start(struct ld_softc *ld, struct buf *bp)
{
/* splbio */
struct ld_virtio_softc *sc = device_private(ld->sc_dv);
struct virtio_softc *vsc = sc->sc_virtio;
struct virtqueue *vq = &sc->sc_vq;
struct virtio_blk_req *vr;
int r;
int isread = (bp->b_flags & B_READ);
int slot;

if (sc->sc_readonly && !isread)
return EIO;

r = virtio_enqueue_prep(vsc, vq, &slot);
if (r != 0)
return r;

vr = &sc->sc_reqs[slot];
KASSERT(vr->vr_bp == NULL);

r = bus_dmamap_load(virtio_dmat(vsc), vr->vr_payload,
bp->b_data, bp->b_bcount, NULL,
((isread?BUS_DMA_READ:BUS_DMA_WRITE)
|BUS_DMA_NOWAIT));
if (r != 0) {
aprint_error_dev(sc->sc_dev,
"payload dmamap failed, error code %d\n", r);
virtio_enqueue_abort(vsc, vq, slot);
return r;
}

KASSERT(vr->vr_payload->dm_nsegs <= sc->sc_seg_max);
r = virtio_enqueue_reserve(vsc, vq, slot, vr->vr_payload->dm_nsegs +
VIRTIO_BLK_CTRL_SEGMENTS);
if (r != 0) {
bus_dmamap_unload(virtio_dmat(vsc), vr->vr_payload);
return r;
}

vr->vr_bp = bp;
vr->vr_hdr.type = virtio_rw32(vsc,
isread ? VIRTIO_BLK_T_IN : VIRTIO_BLK_T_OUT);
vr->vr_hdr.ioprio = virtio_rw32(vsc, 0);
vr->vr_hdr.sector = virtio_rw64(vsc,
bp->b_rawblkno * sc->sc_ld.sc_secsize /
VIRTIO_BLK_BSIZE);

bus_dmamap_sync(virtio_dmat(vsc), vr->vr_cmdsts,
0, sizeof(struct virtio_blk_req_hdr),
BUS_DMASYNC_PREWRITE);
bus_dmamap_sync(virtio_dmat(vsc), vr->vr_payload,
0, bp->b_bcount,
isread?BUS_DMASYNC_PREREAD:BUS_DMASYNC_PREWRITE);
bus_dmamap_sync(virtio_dmat(vsc), vr->vr_cmdsts,
offsetof(struct virtio_blk_req, vr_status),
sizeof(uint8_t),
BUS_DMASYNC_PREREAD);

virtio_enqueue_p(vsc, vq, slot, vr->vr_cmdsts,
0, sizeof(struct virtio_blk_req_hdr),
true);
virtio_enqueue(vsc, vq, slot, vr->vr_payload, !isread);
virtio_enqueue_p(vsc, vq, slot, vr->vr_cmdsts,
offsetof(struct virtio_blk_req, vr_status),
sizeof(uint8_t),
false);
virtio_enqueue_commit(vsc, vq, slot, true);

return 0;
}

static void
ld_virtio_vq_done1(struct ld_virtio_softc *sc, struct virtio_softc *vsc,
struct virtqueue *vq, int slot)
{
struct virtio_blk_req *vr = &sc->sc_reqs[slot];
struct buf *bp = vr->vr_bp;
const uint32_t rt = virtio_rw32(vsc, vr->vr_hdr.type);

vr->vr_bp = NULL;

bus_dmamap_sync(virtio_dmat(vsc), vr->vr_cmdsts,
0, sizeof(struct virtio_blk_req_hdr),
BUS_DMASYNC_POSTWRITE);
bus_dmamap_sync(virtio_dmat(vsc), vr->vr_cmdsts,
sizeof(struct virtio_blk_req_hdr), sizeof(uint8_t),
BUS_DMASYNC_POSTREAD);
if (bp == DUMMY_VR_BP) {
mutex_enter(&sc->sc_sync_wait_lock);
sc->sc_sync_status = vr->vr_status;
sc->sc_sync_use = SYNC_DONE;
cv_broadcast(&sc->sc_sync_wait);
mutex_exit(&sc->sc_sync_wait_lock);
virtio_dequeue_commit(vsc, vq, slot);
return;
}
switch (rt) {
case VIRTIO_BLK_T_OUT:
case VIRTIO_BLK_T_IN:
bus_dmamap_sync(virtio_dmat(vsc), vr->vr_payload,
0, bp->b_bcount,
(bp->b_flags & B_READ)?BUS_DMASYNC_POSTREAD
:BUS_DMASYNC_POSTWRITE);
break;
default:
if (vr->vr_datap == NULL)
break;
bus_dmamap_sync(virtio_dmat(vsc), vr->vr_payload,
0, vr->vr_datas, BUS_DMASYNC_POSTREAD |
BUS_DMASYNC_POSTWRITE);
break;
}
bus_dmamap_unload(virtio_dmat(vsc), vr->vr_payload);

if (vr->vr_status != VIRTIO_BLK_S_OK) {
bp->b_error = EIO;
bp->b_resid = bp->b_bcount;
} else {
bp->b_error = 0;
bp->b_resid = 0;
}

if (vr->vr_datap != NULL) {
kmem_free(vr->vr_datap, vr->vr_datas);
vr->vr_datap = NULL;
vr->vr_datas = 0;
}

virtio_dequeue_commit(vsc, vq, slot);

switch (rt) {
case VIRTIO_BLK_T_OUT:
case VIRTIO_BLK_T_IN:
lddone(&sc->sc_ld, bp);
break;
case VIRTIO_BLK_T_DISCARD:
lddiscardend(&sc->sc_ld, bp);
break;
}
}

static int
ld_virtio_vq_done(struct virtqueue *vq)
{
struct virtio_softc *vsc = vq->vq_owner;
struct ld_virtio_softc *sc = device_private(virtio_child(vsc));
int r = 0;
int slot;

again:
if (virtio_dequeue(vsc, vq, &slot, NULL))
return r;
r = 1;

ld_virtio_vq_done1(sc, vsc, vq, slot);
goto again;
}

static int
ld_virtio_dump(struct ld_softc *ld, void *data, daddr_t blkno, int blkcnt)
{
struct ld_virtio_softc *sc = device_private(ld->sc_dv);
struct virtio_softc *vsc = sc->sc_virtio;
struct virtqueue *vq = &sc->sc_vq;
struct virtio_blk_req *vr;
int slot, r;

if (sc->sc_readonly)
return EIO;

r = virtio_enqueue_prep(vsc, vq, &slot);
if (r != 0) {
if (r == EAGAIN) { /* no free slot; dequeue first */
delay(100);
ld_virtio_vq_done(vq);
r = virtio_enqueue_prep(vsc, vq, &slot);
if (r != 0)
return r;
}
return r;
}
vr = &sc->sc_reqs[slot];
r = bus_dmamap_load(virtio_dmat(vsc), vr->vr_payload,
data, blkcnt*ld->sc_secsize, NULL,
BUS_DMA_WRITE|BUS_DMA_NOWAIT);
if (r != 0)
return r;

r = virtio_enqueue_reserve(vsc, vq, slot, vr->vr_payload->dm_nsegs +
VIRTIO_BLK_CTRL_SEGMENTS);
if (r != 0) {
bus_dmamap_unload(virtio_dmat(vsc), vr->vr_payload);
return r;
}

vr->vr_bp = (void*)0xdeadbeef;
vr->vr_hdr.type = virtio_rw32(vsc, VIRTIO_BLK_T_OUT);
vr->vr_hdr.ioprio = virtio_rw32(vsc, 0);
vr->vr_hdr.sector = virtio_rw64(vsc,
blkno * ld->sc_secsize /
VIRTIO_BLK_BSIZE);

bus_dmamap_sync(virtio_dmat(vsc), vr->vr_cmdsts,
0, sizeof(struct virtio_blk_req_hdr),
BUS_DMASYNC_PREWRITE);
bus_dmamap_sync(virtio_dmat(vsc), vr->vr_payload,
0, blkcnt*ld->sc_secsize,
BUS_DMASYNC_PREWRITE);
bus_dmamap_sync(virtio_dmat(vsc), vr->vr_cmdsts,
offsetof(struct virtio_blk_req, vr_status),
sizeof(uint8_t),
BUS_DMASYNC_PREREAD);

virtio_enqueue_p(vsc, vq, slot, vr->vr_cmdsts,
0, sizeof(struct virtio_blk_req_hdr),
true);
virtio_enqueue(vsc, vq, slot, vr->vr_payload, true);
virtio_enqueue_p(vsc, vq, slot, vr->vr_cmdsts,
offsetof(struct virtio_blk_req, vr_status),
sizeof(uint8_t),
false);
virtio_enqueue_commit(vsc, vq, slot, true);

for ( ; ; ) {
int dslot;

r = virtio_dequeue(vsc, vq, &dslot, NULL);
if (r != 0)
continue;
if (dslot != slot) {
ld_virtio_vq_done1(sc, vsc, vq, dslot);
continue;
} else
break;
}

bus_dmamap_sync(virtio_dmat(vsc), vr->vr_cmdsts,
0, sizeof(struct virtio_blk_req_hdr),
BUS_DMASYNC_POSTWRITE);
bus_dmamap_sync(virtio_dmat(vsc), vr->vr_payload,
0, blkcnt*ld->sc_secsize,
BUS_DMASYNC_POSTWRITE);
bus_dmamap_sync(virtio_dmat(vsc), vr->vr_cmdsts,
offsetof(struct virtio_blk_req, vr_status),
sizeof(uint8_t),
BUS_DMASYNC_POSTREAD);
if (vr->vr_status == VIRTIO_BLK_S_OK)
r = 0;
else
r = EIO;
virtio_dequeue_commit(vsc, vq, slot);

return r;
}

static int
ld_virtio_detach(device_t self, int flags)
{
struct ld_virtio_softc *sc = device_private(self);
struct ld_softc *ld = &sc->sc_ld;
bus_dma_tag_t dmat = virtio_dmat(sc->sc_virtio);
int r, i, qsize;

qsize = sc->sc_vq.vq_num;
r = ldbegindetach(ld, flags);
if (r != 0)
return r;
virtio_reset(sc->sc_virtio);
virtio_free_vq(sc->sc_virtio, &sc->sc_vq);

for (i = 0; i < qsize; i++) {
bus_dmamap_destroy(dmat,
sc->sc_reqs[i].vr_cmdsts);
bus_dmamap_destroy(dmat,
sc->sc_reqs[i].vr_payload);
}
bus_dmamem_unmap(dmat, sc->sc_reqs,
sizeof(struct virtio_blk_req) * qsize);
bus_dmamem_free(dmat, &sc->sc_reqs_seg, 1);

ldenddetach(ld);

if (sc->sc_typename != NULL)
kmem_strfree(sc->sc_typename);

cv_destroy(&sc->sc_sync_wait);
mutex_destroy(&sc->sc_sync_wait_lock);

virtio_child_detach(sc->sc_virtio);

return 0;
}

static int
ld_virtio_flush(struct ld_softc *ld, bool poll)
{
struct ld_virtio_softc * const sc = device_private(ld->sc_dv);
struct virtio_softc * const vsc = sc->sc_virtio;
const uint64_t features = virtio_features(vsc);
struct virtqueue *vq = &sc->sc_vq;
struct virtio_blk_req *vr;
int slot;
int r;

if ((features & VIRTIO_BLK_F_FLUSH) == 0)
return 0;

mutex_enter(&sc->sc_sync_wait_lock);
while (sc->sc_sync_use != SYNC_FREE) {
if (poll) {
mutex_exit(&sc->sc_sync_wait_lock);
ld_virtio_vq_done(vq);
mutex_enter(&sc->sc_sync_wait_lock);
continue;
}
cv_wait(&sc->sc_sync_wait, &sc->sc_sync_wait_lock);
}
sc->sc_sync_use = SYNC_BUSY;
mutex_exit(&sc->sc_sync_wait_lock);

r = virtio_enqueue_prep(vsc, vq, &slot);
if (r != 0) {
return r;
}

vr = &sc->sc_reqs[slot];
KASSERT(vr->vr_bp == NULL);

r = virtio_enqueue_reserve(vsc, vq, slot, VIRTIO_BLK_CTRL_SEGMENTS);
if (r != 0) {
return r;
}

vr->vr_bp = DUMMY_VR_BP;
vr->vr_hdr.type = virtio_rw32(vsc, VIRTIO_BLK_T_FLUSH);
vr->vr_hdr.ioprio = virtio_rw32(vsc, 0);
vr->vr_hdr.sector = virtio_rw64(vsc, 0);

bus_dmamap_sync(virtio_dmat(vsc), vr->vr_cmdsts,
0, sizeof(struct virtio_blk_req_hdr),
BUS_DMASYNC_PREWRITE);
bus_dmamap_sync(virtio_dmat(vsc), vr->vr_cmdsts,
offsetof(struct virtio_blk_req, vr_status),
sizeof(uint8_t),
BUS_DMASYNC_PREREAD);

virtio_enqueue_p(vsc, vq, slot, vr->vr_cmdsts,
0, sizeof(struct virtio_blk_req_hdr),
true);
virtio_enqueue_p(vsc, vq, slot, vr->vr_cmdsts,
offsetof(struct virtio_blk_req, vr_status),
sizeof(uint8_t),
false);
virtio_enqueue_commit(vsc, vq, slot, true);

mutex_enter(&sc->sc_sync_wait_lock);
while (sc->sc_sync_use != SYNC_DONE) {
if (poll) {
mutex_exit(&sc->sc_sync_wait_lock);
ld_virtio_vq_done(vq);
mutex_enter(&sc->sc_sync_wait_lock);
continue;
}
cv_wait(&sc->sc_sync_wait, &sc->sc_sync_wait_lock);
}

if (sc->sc_sync_status == VIRTIO_BLK_S_OK)
r = 0;
else
r = EIO;

sc->sc_sync_use = SYNC_FREE;
cv_broadcast(&sc->sc_sync_wait);
mutex_exit(&sc->sc_sync_wait_lock);

return r;
}

static int
ld_virtio_getcache(struct ld_softc *ld, int *bitsp)
{
struct ld_virtio_softc * const sc = device_private(ld->sc_dv);
struct virtio_softc * const vsc = sc->sc_virtio;
const uint64_t features = virtio_features(vsc);

*bitsp = DKCACHE_READ;
if ((features & VIRTIO_BLK_F_CONFIG_WCE) != 0)
*bitsp |= DKCACHE_WCHANGE;
if (virtio_read_device_config_1(vsc,
VIRTIO_BLK_CONFIG_WRITEBACK) != 0x00)
*bitsp |= DKCACHE_WRITE;

return 0;
}

static int
ld_virtio_setcache(struct ld_softc *ld, int bits)
{
struct ld_virtio_softc * const sc = device_private(ld->sc_dv);
struct virtio_softc * const vsc = sc->sc_virtio;
const uint8_t wce = (bits & DKCACHE_WRITE) ? 0x01 : 0x00;

virtio_write_device_config_1(vsc,
VIRTIO_BLK_CONFIG_WRITEBACK, wce);
if (virtio_read_device_config_1(vsc,
VIRTIO_BLK_CONFIG_WRITEBACK) != wce)
return EIO;

return 0;
}

static int
ld_virtio_ioctl(struct ld_softc *ld, u_long cmd, void *addr, int32_t flag, bool poll)
{
int error;

switch (cmd) {
case DIOCCACHESYNC:
error = ld_virtio_flush(ld, poll);
break;

case DIOCGCACHE:
error = ld_virtio_getcache(ld, (int *)addr);
break;

case DIOCSCACHE:
error = ld_virtio_setcache(ld, *(int *)addr);
break;

default:
error = EPASSTHROUGH;
break;
}

return error;
}

static int
ld_virtio_discard(struct ld_softc *ld, struct buf *bp)
{
struct ld_virtio_softc * const sc = device_private(ld->sc_dv);
struct virtio_softc * const vsc = sc->sc_virtio;
struct virtqueue * const vq = &sc->sc_vq;
struct virtio_blk_req *vr;
const uint64_t features = virtio_features(vsc);
int r;
int slot;
uint64_t blkno;
uint32_t nblks;
struct virtio_blk_discard_write_zeroes * dwz;

if ((features & VIRTIO_BLK_F_DISCARD) == 0 ||
sc->sc_max_discard_seg < 1)
return EINVAL;

if (sc->sc_readonly)
return EIO;

blkno = bp->b_rawblkno * sc->sc_ld.sc_secsize / VIRTIO_BLK_BSIZE;
nblks = bp->b_bcount / VIRTIO_BLK_BSIZE;

if (nblks > sc->sc_max_discard_sectors)
return ERANGE;

r = virtio_enqueue_prep(vsc, vq, &slot);
if (r != 0) {
return r;
}

vr = &sc->sc_reqs[slot];
KASSERT(vr->vr_bp == NULL);

dwz = kmem_alloc(sizeof(*dwz), KM_SLEEP);

r = bus_dmamap_load(virtio_dmat(vsc), vr->vr_payload,
dwz, sizeof(*dwz), NULL, BUS_DMA_WRITE | BUS_DMA_NOWAIT);
if (r != 0) {
device_printf(sc->sc_dev,
"discard payload dmamap failed, error code %d\n", r);
virtio_enqueue_abort(vsc, vq, slot);
kmem_free(dwz, sizeof(*dwz));
return r;
}

KASSERT(vr->vr_payload->dm_nsegs <= sc->sc_seg_max);
r = virtio_enqueue_reserve(vsc, vq, slot, vr->vr_payload->dm_nsegs +
VIRTIO_BLK_CTRL_SEGMENTS);
if (r != 0) {
bus_dmamap_unload(virtio_dmat(vsc), vr->vr_payload);
kmem_free(dwz, sizeof(*dwz));
return r;
}

vr->vr_hdr.type = virtio_rw32(vsc, VIRTIO_BLK_T_DISCARD);
vr->vr_hdr.ioprio = virtio_rw32(vsc, 0);
vr->vr_hdr.sector = virtio_rw64(vsc, 0);
vr->vr_bp = bp;

KASSERT(vr->vr_datap == NULL);
vr->vr_datap = dwz;
vr->vr_datas = sizeof(*dwz);

dwz->sector = virtio_rw64(vsc, blkno);
dwz->num_sectors = virtio_rw32(vsc, nblks);
dwz->flags = virtio_rw32(vsc, 0);

bus_dmamap_sync(virtio_dmat(vsc), vr->vr_cmdsts,
0, sizeof(struct virtio_blk_req_hdr),
BUS_DMASYNC_PREWRITE);
bus_dmamap_sync(virtio_dmat(vsc), vr->vr_payload,
0, vr->vr_datas, BUS_DMASYNC_PREWRITE);
bus_dmamap_sync(virtio_dmat(vsc), vr->vr_cmdsts,
offsetof(struct virtio_blk_req, vr_status),
sizeof(uint8_t),
BUS_DMASYNC_PREREAD);

virtio_enqueue_p(vsc, vq, slot, vr->vr_cmdsts,
0, sizeof(struct virtio_blk_req_hdr),
true);
virtio_enqueue(vsc, vq, slot, vr->vr_payload, true);
virtio_enqueue_p(vsc, vq, slot, vr->vr_cmdsts,
offsetof(struct virtio_blk_req, vr_status),
sizeof(uint8_t),
false);
virtio_enqueue_commit(vsc, vq, slot, true);

return 0;
}

MODULE(MODULE_CLASS_DRIVER, ld_virtio, "ld,virtio");

static int
ld_virtio_modcmd(modcmd_t cmd, void *opaque)
{
int error = 0;

switch (cmd) {
case MODULE_CMD_INIT:
#ifdef _MODULE
error = config_init_component(cfdriver_ioconf_ld_virtio,
cfattach_ioconf_ld_virtio, cfdata_ioconf_ld_virtio);
#endif
break;
case MODULE_CMD_FINI:
#ifdef _MODULE
error = config_fini_component(cfdriver_ioconf_ld_virtio,
cfattach_ioconf_ld_virtio, cfdata_ioconf_ld_virtio);
#endif
break;
default:
error = ENOTTY;
break;
}

return error;
}