[qemu.git] / pc-bios / s390-ccw / virtio.c

/*
 * Virtio driver bits
 *
 * Copyright (c) 2013 Alexander Graf <[email protected]>
 *
 * This work is licensed under the terms of the GNU GPL, version 2 or (at
 * your option) any later version. See the COPYING file in the top-level
 * directory.
 */

#include "s390-ccw.h"
#include "virtio.h"

struct vring block;

static char chsc_page[PAGE_SIZE] __attribute__((__aligned__(PAGE_SIZE)));

static long kvm_hypercall(unsigned long nr, unsigned long param1,
                          unsigned long param2)
{
	register ulong r_nr asm("1") = nr;
	register ulong r_param1 asm("2") = param1;
	register ulong r_param2 asm("3") = param2;
	register long retval asm("2");

	asm volatile ("diag 2,4,0x500"
		      : "=d" (retval)
		      : "d" (r_nr), "0" (r_param1), "r"(r_param2)
		      : "memory", "cc");

	return retval;
}

static void virtio_notify(struct subchannel_id schid)
{
    kvm_hypercall(KVM_S390_VIRTIO_CCW_NOTIFY, *(u32*)&schid, 0);
}

/***********************************************
 *             Virtio functions                *
 ***********************************************/

static int drain_irqs(struct subchannel_id schid)
{
    struct irb irb = {};
    int r = 0;

    while (1) {
        /* FIXME: make use of TPI, for that enable subchannel and isc */
        if (tsch(schid, &irb)) {
            /* Might want to differentiate error codes later on. */
            if (irb.scsw.cstat) {
                r = -EIO;
            } else if (irb.scsw.dstat != 0xc) {
                r = -EIO;
            }
            return r;
        }
    }
}

static int run_ccw(struct subchannel_id schid, int cmd, void *ptr, int len)
{
    struct ccw1 ccw = {};
    struct cmd_orb orb = {};
    struct schib schib;
    int r;

    /* start command processing */
    stsch_err(schid, &schib);
    schib.scsw.ctrl = SCSW_FCTL_START_FUNC;
    msch(schid, &schib);

    /* start subchannel command */
    orb.fmt = 1;
    orb.cpa = (u32)(long)&ccw;
    orb.lpm = 0x80;

    ccw.cmd_code = cmd;
    ccw.cda = (long)ptr;
    ccw.count = len;

    r = ssch(schid, &orb);
    /*
     * XXX Wait until device is done processing the CCW. For now we can
     *     assume that a simple tsch will have finished the CCW processing,
     *     but the architecture allows for asynchronous operation
     */
    if (!r) {
        r = drain_irqs(schid);
    }
    return r;
}

static void virtio_set_status(struct subchannel_id schid,
                              unsigned long dev_addr)
{
    unsigned char status = dev_addr;
    if (run_ccw(schid, CCW_CMD_WRITE_STATUS, &status, sizeof(status))) {
        virtio_panic("Could not write status to host!\n");
    }
}

static void virtio_reset(struct subchannel_id schid)
{
    run_ccw(schid, CCW_CMD_VDEV_RESET, NULL, 0);
}

static void vring_init(struct vring *vr, unsigned int num, void *p,
                       unsigned long align)
{
    debug_print_addr("init p", p);
    vr->num = num;
    vr->desc = p;
    vr->avail = p + num*sizeof(struct vring_desc);
    vr->used = (void *)(((unsigned long)&vr->avail->ring[num] + align-1)
                & ~(align - 1));

    /* Zero out all relevant field */
    vr->avail->flags = 0;
    vr->avail->idx = 0;

    /* We're running with interrupts off anyways, so don't bother */
    vr->used->flags = VRING_USED_F_NO_NOTIFY;
    vr->used->idx = 0;

    debug_print_addr("init vr", vr);
}

static void vring_notify(struct subchannel_id schid)
{
    virtio_notify(schid);
}

static void vring_send_buf(struct vring *vr, void *p, int len, int flags)
{
    /* For follow-up chains we need to keep the first entry point */
    if (!(flags & VRING_HIDDEN_IS_CHAIN)) {
        vr->avail->ring[vr->avail->idx % vr->num] = vr->next_idx;
    }

    vr->desc[vr->next_idx].addr = (ulong)p;
    vr->desc[vr->next_idx].len = len;
    vr->desc[vr->next_idx].flags = flags & ~VRING_HIDDEN_IS_CHAIN;
    vr->desc[vr->next_idx].next = vr->next_idx;
    vr->desc[vr->next_idx].next++;
    vr->next_idx++;

    /* Chains only have a single ID */
    if (!(flags & VRING_DESC_F_NEXT)) {
        vr->avail->idx++;
    }

    vr->used->idx = vr->next_idx;
}

static u64 get_clock(void)
{
    u64 r;

    asm volatile("stck %0" : "=Q" (r) : : "cc");
    return r;
}

static ulong get_second(void)
{
    return (get_clock() >> 12) / 1000000;
}

/*
 * Wait for the host to reply.
 *
 * timeout is in seconds if > 0.
 *
 * Returns 0 on success, 1 on timeout.
 */
static int vring_wait_reply(struct vring *vr, int timeout)
{
    ulong target_second = get_second() + timeout;
    struct subchannel_id schid = vr->schid;
    int r = 0;

    while (vr->used->idx == vr->next_idx) {
        vring_notify(schid);
        if (timeout && (get_second() >= target_second)) {
            r = 1;
            break;
        }
        yield();
    }

    vr->next_idx = 0;
    vr->desc[0].len = 0;
    vr->desc[0].flags = 0;

    return r;
}

/***********************************************
 *               Virtio block                  *
 ***********************************************/

static int virtio_read_many(ulong sector, void *load_addr, int sec_num)
{
    struct virtio_blk_outhdr out_hdr;
    u8 status;
    int r;

    /* Tell the host we want to read */
    out_hdr.type = VIRTIO_BLK_T_IN;
    out_hdr.ioprio = 99;
    out_hdr.sector = sector;

    vring_send_buf(&block, &out_hdr, sizeof(out_hdr), VRING_DESC_F_NEXT);

    /* This is where we want to receive data */
    vring_send_buf(&block, load_addr, SECTOR_SIZE * sec_num,
                   VRING_DESC_F_WRITE | VRING_HIDDEN_IS_CHAIN |
                   VRING_DESC_F_NEXT);

    /* status field */
    vring_send_buf(&block, &status, sizeof(u8), VRING_DESC_F_WRITE |
                   VRING_HIDDEN_IS_CHAIN);

    /* Now we can tell the host to read */
    vring_wait_reply(&block, 0);

    r = drain_irqs(block.schid);
    if (r) {
        /* Well, whatever status is supposed to contain... */
        status = 1;
    }
    return status;
}

unsigned long virtio_load_direct(ulong rec_list1, ulong rec_list2,
				 ulong subchan_id, void *load_addr)
{
    u8 status;
    int sec = rec_list1;
    int sec_num = (((rec_list2 >> 32)+ 1) & 0xffff);
    int sec_len = rec_list2 >> 48;
    ulong addr = (ulong)load_addr;

    if (sec_len != SECTOR_SIZE) {
        return -1;
    }

    sclp_print(".");
    status = virtio_read_many(sec, (void*)addr, sec_num);
    if (status) {
        virtio_panic("I/O Error");
    }
    addr += sec_num * SECTOR_SIZE;

    return addr;
}

int virtio_read(ulong sector, void *load_addr)
{
    return virtio_read_many(sector, load_addr, 1);
}

void virtio_setup_block(struct subchannel_id schid)
{
    struct vq_info_block info;
    struct vq_config_block config = {};

    virtio_reset(schid);

    config.index = 0;
    if (run_ccw(schid, CCW_CMD_READ_VQ_CONF, &config, sizeof(config))) {
        virtio_panic("Could not get block device configuration\n");
    }
    vring_init(&block, config.num, (void*)(100 * 1024 * 1024),
               KVM_S390_VIRTIO_RING_ALIGN);

    info.queue = (100ULL * 1024ULL* 1024ULL);
    info.align = KVM_S390_VIRTIO_RING_ALIGN;
    info.index = 0;
    info.num = config.num;
    block.schid = schid;

    if (!run_ccw(schid, CCW_CMD_SET_VQ, &info, sizeof(info))) {
        virtio_set_status(schid, VIRTIO_CONFIG_S_DRIVER_OK);
    }
}

bool virtio_is_blk(struct subchannel_id schid)
{
    int r;
    struct senseid senseid = {};

    /* run sense id command */
    r = run_ccw(schid, CCW_CMD_SENSE_ID, &senseid, sizeof(senseid));
    if (r) {
        return false;
    }
    if ((senseid.cu_type != 0x3832) || (senseid.cu_model != VIRTIO_ID_BLOCK)) {
        return false;
    }

    return true;
}

int enable_mss_facility(void)
{
    int ret;
    struct chsc_area_sda *sda_area = (struct chsc_area_sda *) chsc_page;

    memset(sda_area, 0, PAGE_SIZE);
    sda_area->request.length = 0x0400;
    sda_area->request.code = 0x0031;
    sda_area->operation_code = 0x2;

    ret = chsc(sda_area);
    if ((ret == 0) && (sda_area->response.code == 0x0001)) {
        return 0;
    }
    return -EIO;
}
Commit	Line	Data
1e17c2c1 AG	1	/*
	2	* Virtio driver bits
	3	*
	4	* Copyright (c) 2013 Alexander Graf <[email protected]>
	5	*
	6	* This work is licensed under the terms of the GNU GPL, version 2 or (at
	7	* your option) any later version. See the COPYING file in the top-level
	8	* directory.
	9	*/
	10
	11	#include "s390-ccw.h"
	12	#include "virtio.h"
	13
	14	struct vring block;
	15
c8cda874 DD	16	static char chsc_page[PAGE_SIZE] __attribute__((__aligned__(PAGE_SIZE)));
c8cda874 DD	17
1e17c2c1 AG	18	static long kvm_hypercall(unsigned long nr, unsigned long param1,
	19	unsigned long param2)
	20	{
	21	register ulong r_nr asm("1") = nr;
	22	register ulong r_param1 asm("2") = param1;
	23	register ulong r_param2 asm("3") = param2;
	24	register long retval asm("2");
	25
	26	asm volatile ("diag 2,4,0x500"
	27	: "=d" (retval)
	28	: "d" (r_nr), "0" (r_param1), "r"(r_param2)
	29	: "memory", "cc");
	30
	31	return retval;
	32	}
	33
	34	static void virtio_notify(struct subchannel_id schid)
	35	{
	36	kvm_hypercall(KVM_S390_VIRTIO_CCW_NOTIFY, (u32)&schid, 0);
	37	}
	38
	39	/***********************************************
	40	* Virtio functions *
	41	***********************************************/
	42
776e7f0f	43	static int drain_irqs(struct subchannel_id schid)
1e17c2c1 AG	44	{
1e17c2c1 AG	45	struct irb irb = {};
776e7f0f CH	46	int r = 0;
776e7f0f CH	47
1e17c2c1	48	while (1) {
776e7f0f	49	/* FIXME: make use of TPI, for that enable subchannel and isc */
1e17c2c1	50	if (tsch(schid, &irb)) {
776e7f0f CH	51	/* Might want to differentiate error codes later on. */
	52	if (irb.scsw.cstat) {
	53	r = -EIO;
	54	} else if (irb.scsw.dstat != 0xc) {
	55	r = -EIO;
	56	}
	57	return r;
1e17c2c1 AG	58	}
	59	}
	60	}
	61
	62	static int run_ccw(struct subchannel_id schid, int cmd, void *ptr, int len)
	63	{
	64	struct ccw1 ccw = {};
	65	struct cmd_orb orb = {};
	66	struct schib schib;
	67	int r;
	68
	69	/* start command processing */
	70	stsch_err(schid, &schib);
	71	schib.scsw.ctrl = SCSW_FCTL_START_FUNC;
	72	msch(schid, &schib);
	73
	74	/* start subchannel command */
	75	orb.fmt = 1;
	76	orb.cpa = (u32)(long)&ccw;
	77	orb.lpm = 0x80;
	78
	79	ccw.cmd_code = cmd;
	80	ccw.cda = (long)ptr;
	81	ccw.count = len;
	82
	83	r = ssch(schid, &orb);
	84	/*
	85	* XXX Wait until device is done processing the CCW. For now we can
	86	* assume that a simple tsch will have finished the CCW processing,
	87	* but the architecture allows for asynchronous operation
	88	*/
0f3f1f30 CH	89	if (!r) {
	90	r = drain_irqs(schid);
	91	}
1e17c2c1 AG	92	return r;
	93	}
	94
	95	static void virtio_set_status(struct subchannel_id schid,
	96	unsigned long dev_addr)
	97	{
	98	unsigned char status = dev_addr;
0f3f1f30 CH	99	if (run_ccw(schid, CCW_CMD_WRITE_STATUS, &status, sizeof(status))) {
	100	virtio_panic("Could not write status to host!\n");
	101	}
1e17c2c1 AG	102	}
	103
	104	static void virtio_reset(struct subchannel_id schid)
	105	{
	106	run_ccw(schid, CCW_CMD_VDEV_RESET, NULL, 0);
	107	}
	108
	109	static void vring_init(struct vring vr, unsigned int num, void p,
	110	unsigned long align)
	111	{
	112	debug_print_addr("init p", p);
	113	vr->num = num;
	114	vr->desc = p;
	115	vr->avail = p + num*sizeof(struct vring_desc);
	116	vr->used = (void *)(((unsigned long)&vr->avail->ring[num] + align-1)
	117	& ~(align - 1));
	118
39c93c67 CB	119	/* Zero out all relevant field */
	120	vr->avail->flags = 0;
	121	vr->avail->idx = 0;
	122
1e17c2c1 AG	123	/* We're running with interrupts off anyways, so don't bother */
1e17c2c1 AG	124	vr->used->flags = VRING_USED_F_NO_NOTIFY;
39c93c67	125	vr->used->idx = 0;
1e17c2c1 AG	126
	127	debug_print_addr("init vr", vr);
	128	}
	129
	130	static void vring_notify(struct subchannel_id schid)
	131	{
	132	virtio_notify(schid);
	133	}
	134
	135	static void vring_send_buf(struct vring vr, void p, int len, int flags)
	136	{
	137	/* For follow-up chains we need to keep the first entry point */
	138	if (!(flags & VRING_HIDDEN_IS_CHAIN)) {
	139	vr->avail->ring[vr->avail->idx % vr->num] = vr->next_idx;
	140	}
	141
	142	vr->desc[vr->next_idx].addr = (ulong)p;
	143	vr->desc[vr->next_idx].len = len;
	144	vr->desc[vr->next_idx].flags = flags & ~VRING_HIDDEN_IS_CHAIN;
dc03640b CB	145	vr->desc[vr->next_idx].next = vr->next_idx;
	146	vr->desc[vr->next_idx].next++;
	147	vr->next_idx++;
1e17c2c1 AG	148
	149	/* Chains only have a single ID */
	150	if (!(flags & VRING_DESC_F_NEXT)) {
	151	vr->avail->idx++;
	152	}
	153
	154	vr->used->idx = vr->next_idx;
	155	}
	156
	157	static u64 get_clock(void)
	158	{
	159	u64 r;
	160
	161	asm volatile("stck %0" : "=Q" (r) : : "cc");
	162	return r;
	163	}
	164
	165	static ulong get_second(void)
	166	{
	167	return (get_clock() >> 12) / 1000000;
	168	}
	169
	170	/*
	171	* Wait for the host to reply.
	172	*
	173	* timeout is in seconds if > 0.
	174	*
	175	* Returns 0 on success, 1 on timeout.
	176	*/
	177	static int vring_wait_reply(struct vring *vr, int timeout)
	178	{
	179	ulong target_second = get_second() + timeout;
	180	struct subchannel_id schid = vr->schid;
	181	int r = 0;
	182
	183	while (vr->used->idx == vr->next_idx) {
	184	vring_notify(schid);
	185	if (timeout && (get_second() >= target_second)) {
	186	r = 1;
	187	break;
	188	}
	189	yield();
	190	}
	191
	192	vr->next_idx = 0;
	193	vr->desc[0].len = 0;
	194	vr->desc[0].flags = 0;
	195
	196	return r;
	197	}
	198
	199	/***********************************************
	200	* Virtio block *
	201	***********************************************/
	202
	203	static int virtio_read_many(ulong sector, void *load_addr, int sec_num)
	204	{
	205	struct virtio_blk_outhdr out_hdr;
	206	u8 status;
0f3f1f30	207	int r;
1e17c2c1 AG	208
	209	/* Tell the host we want to read */
	210	out_hdr.type = VIRTIO_BLK_T_IN;
	211	out_hdr.ioprio = 99;
	212	out_hdr.sector = sector;
	213
	214	vring_send_buf(&block, &out_hdr, sizeof(out_hdr), VRING_DESC_F_NEXT);
	215
	216	/* This is where we want to receive data */
	217	vring_send_buf(&block, load_addr, SECTOR_SIZE * sec_num,
	218	VRING_DESC_F_WRITE \| VRING_HIDDEN_IS_CHAIN \|
	219	VRING_DESC_F_NEXT);
	220
	221	/* status field */
	222	vring_send_buf(&block, &status, sizeof(u8), VRING_DESC_F_WRITE \|
	223	VRING_HIDDEN_IS_CHAIN);
	224
	225	/* Now we can tell the host to read */
	226	vring_wait_reply(&block, 0);
	227
0f3f1f30 CH	228	r = drain_irqs(block.schid);
	229	if (r) {
	230	/* Well, whatever status is supposed to contain... */
	231	status = 1;
	232	}
1e17c2c1 AG	233	return status;
	234	}
	235
	236	unsigned long virtio_load_direct(ulong rec_list1, ulong rec_list2,
	237	ulong subchan_id, void *load_addr)
	238	{
	239	u8 status;
	240	int sec = rec_list1;
	241	int sec_num = (((rec_list2 >> 32)+ 1) & 0xffff);
	242	int sec_len = rec_list2 >> 48;
	243	ulong addr = (ulong)load_addr;
	244
	245	if (sec_len != SECTOR_SIZE) {
	246	return -1;
	247	}
	248
	249	sclp_print(".");
	250	status = virtio_read_many(sec, (void*)addr, sec_num);
	251	if (status) {
	252	virtio_panic("I/O Error");
	253	}
	254	addr += sec_num * SECTOR_SIZE;
	255
	256	return addr;
	257	}
	258
	259	int virtio_read(ulong sector, void *load_addr)
	260	{
	261	return virtio_read_many(sector, load_addr, 1);
	262	}
	263
	264	void virtio_setup_block(struct subchannel_id schid)
	265	{
	266	struct vq_info_block info;
abbbe3de	267	struct vq_config_block config = {};
1e17c2c1 AG	268
	269	virtio_reset(schid);
	270
abbbe3de CH	271	config.index = 0;
	272	if (run_ccw(schid, CCW_CMD_READ_VQ_CONF, &config, sizeof(config))) {
	273	virtio_panic("Could not get block device configuration\n");
	274	}
	275	vring_init(&block, config.num, (void)(100 1024 * 1024),
1e17c2c1 AG	276	KVM_S390_VIRTIO_RING_ALIGN);
	277
	278	info.queue = (100ULL * 1024ULL* 1024ULL);
	279	info.align = KVM_S390_VIRTIO_RING_ALIGN;
	280	info.index = 0;
abbbe3de	281	info.num = config.num;
1e17c2c1 AG	282	block.schid = schid;
1e17c2c1 AG	283
0f3f1f30 CH	284	if (!run_ccw(schid, CCW_CMD_SET_VQ, &info, sizeof(info))) {
	285	virtio_set_status(schid, VIRTIO_CONFIG_S_DRIVER_OK);
	286	}
1e17c2c1 AG	287	}
	288
	289	bool virtio_is_blk(struct subchannel_id schid)
	290	{
	291	int r;
	292	struct senseid senseid = {};
	293
	294	/* run sense id command */
	295	r = run_ccw(schid, CCW_CMD_SENSE_ID, &senseid, sizeof(senseid));
	296	if (r) {
	297	return false;
	298	}
	299	if ((senseid.cu_type != 0x3832) \|\| (senseid.cu_model != VIRTIO_ID_BLOCK)) {
	300	return false;
	301	}
	302
	303	return true;
	304	}
	305
c8cda874 DD	306	int enable_mss_facility(void)
	307	{
	308	int ret;
	309	struct chsc_area_sda sda_area = (struct chsc_area_sda ) chsc_page;
	310
	311	memset(sda_area, 0, PAGE_SIZE);
	312	sda_area->request.length = 0x0400;
	313	sda_area->request.code = 0x0031;
	314	sda_area->operation_code = 0x2;
	315
	316	ret = chsc(sda_area);
	317	if ((ret == 0) && (sda_area->response.code == 0x0001)) {
	318	return 0;
	319	}
	320	return -EIO;
	321	}