path: root/arch/sparc/kernel/viohs.c

/* viohs.c: LDOM Virtual I/O handshake helper layer.
 *
 * Copyright (C) 2007 David S. Miller <davem@davemloft.net>
 */

#include <linux/kernel.h>
#include <linux/export.h>
#include <linux/string.h>
#include <linux/delay.h>
#include <linux/sched.h>
#include <linux/slab.h>

#include <asm/ldc.h>
#include <asm/vio.h>

int vio_ldc_send(struct vio_driver_state *vio, void *data, int len)
{
	int err, limit = 1000;

	err = -EINVAL;
	while (limit-- > 0) {
		err = ldc_write(vio->lp, data, len);
		if (!err || (err != -EAGAIN))
			break;
		udelay(1);
	}

	return err;
}
EXPORT_SYMBOL(vio_ldc_send);

static int send_ctrl(struct vio_driver_state *vio,
		     struct vio_msg_tag *tag, int len)
{
	tag->sid = vio_send_sid(vio);
	return vio_ldc_send(vio, tag, len);
}

static void init_tag(struct vio_msg_tag *tag, u8 type, u8 stype, u16 stype_env)
{
	tag->type = type;
	tag->stype = stype;
	tag->stype_env = stype_env;
}

static int send_version(struct vio_driver_state *vio, u16 major, u16 minor)
{
	struct vio_ver_info pkt;

	vio->_local_sid = (u32) sched_clock();

	memset(&pkt, 0, sizeof(pkt));
	init_tag(&pkt.tag, VIO_TYPE_CTRL, VIO_SUBTYPE_INFO, VIO_VER_INFO);
	pkt.major = major;
	pkt.minor = minor;
	pkt.dev_class = vio->dev_class;

	viodbg(HS, "SEND VERSION INFO maj[%u] min[%u] devclass[%u]\n",
	       major, minor, vio->dev_class);

	return send_ctrl(vio, &pkt.tag, sizeof(pkt));
}

static int start_handshake(struct vio_driver_state *vio)
{
	int err;

	viodbg(HS, "START HANDSHAKE\n");

	vio->hs_state = VIO_HS_INVALID;

	err = send_version(vio,
			   vio->ver_table[0].major,
			   vio->ver_table[0].minor);
	if (err < 0)
		return err;

	return 0;
}

static void flush_rx_dring(struct vio_driver_state *vio)
{
	struct vio_dring_state *dr;
	u64 ident;

	BUG_ON(!(vio->dr_state & VIO_DR_STATE_RXREG));

	dr = &vio->drings[VIO_DRIVER_RX_RING];
	ident = dr->ident;

	BUG_ON(!vio->desc_buf);
	kfree(vio->desc_buf);
	vio->desc_buf = NULL;

	memset(dr, 0, sizeof(*dr));
	dr->ident = ident;
}

void vio_link_state_change(struct vio_driver_state *vio, int event)
{
	if (event == LDC_EVENT_UP) {
		vio->hs_state = VIO_HS_INVALID;

		switch (vio->dev_class) {
		case VDEV_NETWORK:
		case VDEV_NETWORK_SWITCH:
			vio->dr_state = (VIO_DR_STATE_TXREQ |
					 VIO_DR_STATE_RXREQ);
			break;

		case VDEV_DISK:
			vio->dr_state = VIO_DR_STATE_TXREQ;
			break;
		case VDEV_DISK_SERVER:
			vio->dr_state = VIO_DR_STATE_RXREQ;
			break;
		}
		start_handshake(vio);
	} else if (event == LDC_EVENT_RESET) {
		vio->hs_state = VIO_HS_INVALID;

		if (vio->dr_state & VIO_DR_STATE_RXREG)
			flush_rx_dring(vio);

		vio->dr_state = 0x00;
		memset(&vio->ver, 0, sizeof(vio->ver));

		ldc_disconnect(vio->lp);
	}
}
EXPORT_SYMBOL(vio_link_state_change);

static int handshake_failure(struct vio_driver_state *vio)
{
	struct vio_dring_state *dr;

	/* XXX Put policy here...  Perhaps start a timer to fire
	 * XXX in 100 ms, which will bring the link up and retry
	 * XXX the handshake.
	 */

	viodbg(HS, "HANDSHAKE FAILURE\n");

	vio->dr_state &= ~(VIO_DR_STATE_TXREG |
			   VIO_DR_STATE_RXREG);

	dr = &vio->drings[VIO_DRIVER_RX_RING];
	memset(dr, 0, sizeof(*dr));

	kfree(vio->desc_buf);
	vio->desc_buf = NULL;
	vio->desc_buf_len = 0;

	vio->hs_state = VIO_HS_INVALID;

	return -ECONNRESET;
}

static int process_unknown(struct vio_driver_state *vio, void *arg)
{
	struct vio_msg_tag *pkt = arg;

	viodbg(HS, "UNKNOWN CONTROL [%02x:%02x:%04x:%08x]\n",
	       pkt->type, pkt->stype, pkt->stype_env, pkt->sid);

	printk(KERN_ERR "vio: ID[%lu] Resetting connection.\n",
	       vio->vdev->channel_id);

	ldc_disconnect(vio->lp);

	return -ECONNRESET;
}

static int send_dreg(struct vio_driver_state *vio)
{
	struct vio_dring_state *dr = &vio->drings[VIO_DRIVER_TX_RING];
	union {
		struct vio_dring_register pkt;
		char all[sizeof(struct vio_dring_register) +
			 (sizeof(struct ldc_trans_cookie) *
			  dr->ncookies)];
	} u;
	int i;

	memset(