ntb_hw_switchtec.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Microsemi Switchtec(tm) PCIe Management Driver
 * Copyright (c) 2017, Microsemi Corporation
 */

#include <linux/interrupt.h>
#include <linux/io-64-nonatomic-lo-hi.h>
#include <linux/delay.h>
#include <linux/kthread.h>
#include <linux/module.h>
#include <linux/ntb.h>
#include <linux/pci.h>
#include <linux/switchtec.h>

MODULE_DESCRIPTION("Microsemi Switchtec(tm) NTB Driver");
MODULE_VERSION("0.1");
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Microsemi Corporation");

static ulong max_mw_size = SZ_2M;
module_param(max_mw_size, ulong, 0644);
MODULE_PARM_DESC(max_mw_size,
	"Max memory window size reported to the upper layer");

static bool use_lut_mws;
module_param(use_lut_mws, bool, 0644);
MODULE_PARM_DESC(use_lut_mws,
		 "Enable the use of the LUT based memory windows");

#define SWITCHTEC_NTB_MAGIC 0x45CC0001
#define MAX_MWS     128

struct shared_mw {
	u32 magic;
	u32 link_sta;
	u32 partition_id;
	u64 mw_sizes[MAX_MWS];
	u32 spad[128];
};

#define MAX_DIRECT_MW ARRAY_SIZE(((struct ntb_ctrl_regs *)(0))->bar_entry)
#define LUT_SIZE SZ_64K

struct switchtec_ntb {
	struct ntb_dev ntb;
	struct switchtec_dev *stdev;

	int self_partition;
	int peer_partition;

	int doorbell_irq;
	int message_irq;

	struct ntb_info_regs __iomem *mmio_ntb;
	struct ntb_ctrl_regs __iomem *mmio_ctrl;
	struct ntb_dbmsg_regs __iomem *mmio_dbmsg;
	struct ntb_ctrl_regs __iomem *mmio_self_ctrl;
	struct ntb_ctrl_regs __iomem *mmio_peer_ctrl;
	struct ntb_dbmsg_regs __iomem *mmio_self_dbmsg;
	struct ntb_dbmsg_regs __iomem *mmio_peer_dbmsg;

	void __iomem *mmio_xlink_win;

	struct shared_mw *self_shared;
	struct shared_mw __iomem *peer_shared;
	dma_addr_t self_shared_dma;

	u64 db_mask;
	u64 db_valid_mask;
	int db_shift;
	int db_peer_shift;

	/* synchronize rmw access of db_mask and hw reg */
	spinlock_t db_mask_lock;

	int nr_direct_mw;
	int nr_lut_mw;
	int nr_rsvd_luts;
	int direct_mw_to_bar[MAX_DIRECT_MW];

	int peer_nr_direct_mw;
	int peer_nr_lut_mw;
	int peer_direct_mw_to_bar[MAX_DIRECT_MW];

	bool link_is_up;
	enum ntb_speed link_speed;
	enum ntb_width link_width;
	struct work_struct check_link_status_work;
	bool link_force_down;
};

static struct switchtec_ntb *ntb_sndev(struct ntb_dev *ntb)
{
	return container_of(ntb, struct switchtec_ntb, ntb);
}

static int switchtec_ntb_part_op(struct switchtec_ntb *sndev,
				 struct ntb_ctrl_regs __iomem *ctl,
				 u32 op, int wait_status)
{
	static const char * const op_text[] = {
		[NTB_CTRL_PART_OP_LOCK] = "lock",
		[NTB_CTRL_PART_OP_CFG] = "configure",
		[NTB_CTRL_PART_OP_RESET] = "reset",
	};

	int i;
	u32 ps;
	int status;

	switch (op) {
	case NTB_CTRL_PART_OP_LOCK:
		status = NTB_CTRL_PART_STATUS_LOCKING;
		break;
	case NTB_CTRL_PART_OP_CFG:
		status = NTB_CTRL_PART_STATUS_CONFIGURING;
		break;
	case NTB_CTRL_PART_OP_RESET:
		status = NTB_CTRL_PART_STATUS_RESETTING;
		break;
	default:
		return -EINVAL;
	}

	iowrite32(op, &ctl->partition_op);

	for (i = 0; i < 1000; i++) {
		if (msleep_interruptible(50) != 0) {
			iowrite32(NTB_CTRL_PART_OP_RESET, &ctl->partition_op);
			return -EINTR;
		}

		ps = ioread32(&ctl->partition_status) & 0xFFFF;

		if (ps != status)
			break;
	}

	if (ps == wait_status)
		return 0;

	if (ps == status) {
		dev_err(&sndev->stdev->dev,
			"Timed out while performing %s (%d). (%08x)\n",
			op_text[op], op,
			ioread32(&ctl->partition_status));

		return -ETIMEDOUT;
	}

	return -EIO;
}

static int switchtec_ntb_send_msg(struct switchtec_ntb *sndev, int idx,
				  u32 val)
{
	if (idx < 0 || idx >= ARRAY_SIZE(sndev->mmio_peer_dbmsg->omsg))
		return -EINVAL;

	iowrite32(val, &sndev->mmio_peer_dbmsg->omsg[idx].msg);

	return 0;
}

static int switchtec_ntb_mw_count(struct ntb_dev *ntb, int pidx)
{
	struct switchtec_ntb *sndev = ntb_sndev(ntb);
	int nr_direct_mw = sndev->peer_nr_direct_mw;
	int nr_lut_mw = sndev->peer_nr_lut_mw - sndev->nr_rsvd_luts;

	if (pidx != NTB_DEF_PEER_IDX)
		return -EINVAL;

	if (!use_lut_mws)
		nr_lut_mw = 0;

	return nr_direct_mw + nr_lut_mw;
}

static int lut_index(struct switchtec_ntb *sndev, int mw_idx)
{
	return mw_idx - sndev->nr_direct_mw + sndev->nr_rsvd_luts;
}

static int peer_lut_index(struct switchtec_ntb *sndev, int mw_idx)
{
	return mw_idx - sndev->peer_nr_direct_mw + sndev->nr_rsvd_luts;
}

static int switchtec_ntb_mw_get_align(struct ntb_dev *ntb, int pidx,
				      int widx, resource_size_t *addr_align,
				      resource_size_t *size_align,
				      resource_size_t *size_max)
{
	struct switchtec_ntb *sndev = ntb_sndev(ntb);
	int lut;
	resource_size_t size;

	if (pidx != NTB_DEF_PEER_IDX)
		return -EINVAL;

	lut = widx >= sndev->peer_nr_direct_mw;
	size = ioread64(&sndev->peer_shared->mw_sizes[widx]);

	if (size == 0)
		return -EINVAL;

	if (addr_align)
		*addr_align = lut ? size : SZ_4K;

	if (size_align)
		*size_align = lut ? size : SZ_4K;

	if (size_max)
		*size_max = size;

	return 0;
}

static void switchtec_ntb_mw_clr_direct(struct switchtec_ntb *sndev, int idx)
{
	struct ntb_ctrl_regs __iomem *ctl = sndev->mmio_peer_ctrl;
	int bar = sndev->peer_direct_mw_to_bar[idx];
	u32 ctl_val;

	ctl_val = ioread32(&ctl->bar_entry[bar].ctl);
	ctl_val &= ~NTB_CTRL_BAR_DIR_WIN_EN;
	iowrite32(ctl_val, &ctl->bar_entry[bar].ctl);
	iowrite32(0, &ctl->bar_entry[bar].win_size);
	iowrite32(0, &ctl->bar_ext_entry[bar].win_size);
	iowrite64(sndev->self_partition, &ctl->bar_entry[bar].xlate_addr);
}

static void switchtec_ntb_mw_clr_lut(struct switchtec_ntb *sndev, int idx)
{
	struct ntb_ctrl_regs __iomem *ctl = sndev->mmio_peer_ctrl;

	iowrite64(0, &ctl->lut_entry[peer_lut_index(sndev, idx)]);
}

static void switchtec_ntb_mw_set_direct(struct switchtec_ntb *sndev, int idx,
					dma_addr_t addr, resource_size_t size)
{
	int xlate_pos = ilog2(size);
	int bar = sndev->peer_direct_mw_to_bar[idx];
	struct ntb_ctrl_regs __iomem *ctl = sndev->mmio_peer_ctrl;
	u32 ctl_val;

	ctl_val = ioread32(&ctl->bar_entry[bar].ctl);
	ctl_val |= NTB_CTRL_BAR_DIR_WIN_EN;

	iowrite32(ctl_val, &ctl->bar_entry[bar].ctl);
	iowrite32(xlate_pos | (lower_32_bits(size) & 0xFFFFF000),
		  &ctl->bar_entry[bar].win_size);
	iowrite32(upper_32_bits(size), &ctl->bar_ext_entry[bar].win_size);
	iowrite64(sndev->self_partition | addr,
		  &ctl->bar_entry[bar].xlate_addr);
}

static void switchtec_ntb_mw_set_lut(struct switchtec_ntb *sndev, int idx,
				     dma_addr_t addr, resource_size_t size)
{
	struct ntb_ctrl_regs __iomem *ctl = sndev->mmio_peer_ctrl;

	iowrite64((NTB_CTRL_LUT_EN | (sndev->self_partition << 1) | addr),
		  &ctl->lut_entry[peer_lut_index(sndev, idx)]);
}

static int switchtec_ntb_mw_set_trans(struct ntb_dev *ntb, int pidx, int widx,
				      dma_addr_t addr, resource_size_t size)
{
	struct switchtec_ntb *sndev = ntb_sndev(ntb);
	struct ntb_ctrl_regs __iomem *ctl = sndev->mmio_peer_ctrl;
	int xlate_pos = ilog2(size);
	int nr_direct_mw = sndev->peer_nr_direct_mw;
	int rc;

	if (pidx != NTB_DEF_PEER_IDX)
		return -EINVAL;

	dev_dbg(&sndev->stdev->dev, "MW %d: part %d addr %pad size %pap\n",
		widx, pidx, &addr, &size);

	if (widx >= switchtec_ntb_mw_count(ntb, pidx))
		return -EINVAL;

	if (size != 0 && xlate_pos < 12)
		return -EINVAL;

	if (!IS_ALIGNED(addr, BIT_ULL(xlate_pos))) {
		/*
		 * In certain circumstances we can get a buffer that is
		 * not aligned to its size. (Most of the time
		 * dma_alloc_coherent ensures this). This can happen when
		 * using large buffers allocated by the CMA
		 * (see CMA_CONFIG_ALIGNMENT)
		 */
		dev_err(&sndev->stdev->dev,
			"ERROR: Memory window address is not aligned to it's size!\n");
		return -EINVAL;
	}

	rc = switchtec_ntb_part_op(sndev, ctl, NTB_CTRL_PART_OP_LOCK,
				   NTB_CTRL_PART_STATUS_LOCKED);
	if (rc)
		return rc;

	if (size == 0) {
		if (widx < nr_direct_mw)
			switchtec_ntb_mw_clr_direct(sndev, widx);
		else
			switchtec_ntb_mw_clr_lut(sndev, widx);
	} else {
		if (widx < nr_direct_mw)
			switchtec_ntb_mw_set_direct(sndev, widx, addr, size);
		else
			switchtec_ntb_mw_set_lut(sndev, widx, addr, size);
	}

	rc = switchtec_ntb_part_op(sndev, ctl, NTB_CTRL_PART_OP_CFG,
				   NTB_CTRL_PART_STATUS_NORMAL);

	if (rc == -EIO) {
		dev_err(&sndev->stdev->dev,
			"Hardware reported an error configuring mw %d: %08x\n",
			widx, ioread32(&ctl->bar_error));

		if (widx < nr_direct_mw)
			switchtec_ntb_mw_clr_direct(sndev, widx);
		else
			switchtec_ntb_mw_clr_lut(sndev, widx);

		switchtec_ntb_part_op(sndev, ctl, NTB_CTRL_PART_OP_CFG,
				      NTB_CTRL_PART_STATUS_NORMAL);
	}

	return rc;
}

static int switchtec_ntb_peer_mw_count(struct ntb_dev *ntb)
{
	struct switchtec_ntb *sndev = ntb_sndev(ntb);
	int nr_lut_mw = sndev->nr_lut_mw - sndev->nr_rsvd_luts;

	return sndev->nr_direct_mw + (use_lut_mws ? nr_lut_mw : 0);
}

static int switchtec_ntb_direct_get_addr(struct switchtec_ntb *sndev,
					 int idx, phys_addr_t *base,
					 resource_size_t *size)
{
	int bar = sndev->direct_mw_to_bar[idx];
	size_t offset = 0;

	if (bar < 0)
		return -EINVAL;

	if (idx == 0) {
		/*
		 * This is the direct BAR shared with the LUTs
		 * which means the actual window will be offset
		 * by the size of all the LUT entries.
		 */

		offset = LUT_SIZE * sndev->nr_lut_mw;
	}

	if (base)
		*base = pci_resource_start(sndev->ntb.pdev, bar) + offset;

	if (size) {
		*size = pci_resource_len(sndev->ntb.pdev, bar) - offset;
		if (offset && *size > offset)
			*size = offset;

		if (*size > max_mw_size)
			*size = max_mw_size;
	}

	return 0;
}

static int switchtec_ntb_lut_get_addr(struct switchtec_ntb *sndev,
				      int idx, phys_addr_t *base,
				      resource_size_t *size)
{
	int bar = sndev->direct_mw_to_bar[0];
	int offset;

	offset = LUT_SIZE * lut_index(sndev, idx);

	if (base)
		*base = pci_resource_start(sndev->ntb.pdev, bar) + offset;

	if (size)
		*size = LUT_SIZE;

	return 0;
}

static int switchtec_ntb_peer_mw_get_addr(struct ntb_dev *ntb, int idx,
					  phys_addr_t *base,
					  resource_size_t *size)
{
	struct switchtec_ntb *sndev = ntb_sndev(ntb);

	if (idx < sndev->nr_direct_mw)
		return switchtec_ntb_direct_get_addr(sndev, idx, base, size);
	else if (idx < switchtec_ntb_peer_mw_count(ntb))
		return switchtec_ntb_lut_get_addr(sndev, idx, base, size);
	else
		return -EINVAL;
}

static void switchtec_ntb_part_link_speed(struct switchtec_ntb *sndev,
					  int partition,
					  enum ntb_speed *speed,
					  enum ntb_width *width)
{
	struct switchtec_dev *stdev = sndev->stdev;
	u32 pff =
		ioread32(&stdev->mmio_part_cfg_all[partition].vep_pff_inst_id);
	u32 linksta = ioread32(&stdev->mmio_pff_csr[pff].pci_cap_region[13]);

	if (speed)
		*speed = (linksta >> 16) & 0xF;

	if (width)
		*width = (linksta >> 20) & 0x3F;
}

static void switchtec_ntb_set_link_speed(struct switchtec_ntb *sndev)
{
	enum ntb_speed self_speed, peer_speed;
	enum ntb_width self_width, peer_width;

	if (!sndev->link_is_up) {
		sndev->link_speed = NTB_SPEED_NONE;
		sndev->link_width = NTB_WIDTH_NONE;
		return;
	}

	switchtec_ntb_part_link_speed(sndev, sndev->self_partition,
				      &self_speed, &self_width);
	switchtec_ntb_part_link_speed(sndev, sndev->peer_partition,
				      &peer_speed, &peer_width);

	sndev->link_speed = min(self_speed, peer_speed);
	sndev->link_width = min(self_width, peer_width);
}

static int crosslink_is_enabled(struct switchtec_ntb *sndev)
{
	struct ntb_info_regs __iomem *inf = sndev->mmio_ntb;

	return ioread8(&inf->ntp_info[sndev->peer_partition].xlink_enabled);
}

static void crosslink_init_dbmsgs(struct switchtec_ntb *sndev)
{
	int i;
	u32 msg_map = 0;

	if (!crosslink_is_enabled(sndev))
		return;

	for (i = 0; i < ARRAY_SIZE(sndev->mmio_peer_dbmsg->imsg); i++) {
		int m = i | sndev->self_partition << 2;

		msg_map |= m << i * 8;
	}

	iowrite32(msg_map, &sndev->mmio_peer_dbmsg->msg_map);
	iowrite64(sndev->db_valid_mask << sndev->db_peer_shift,
		  &sndev->mmio_peer_dbmsg->odb_mask);
}

enum switchtec_msg {
	LINK_MESSAGE = 0,
	MSG_LINK_UP = 1,
	MSG_LINK_DOWN = 2,
	MSG_CHECK_LINK = 3,
	MSG_LINK_FORCE_DOWN = 4,
};

static int switchtec_ntb_reinit_peer(struct switchtec_ntb *sndev);

static void switchtec_ntb_link_status_update(struct switchtec_ntb *sndev)
{
	int link_sta;
	int old = sndev->link_is_up;

	link_sta = sndev->self_shared->link_sta;
	if (link_sta) {
		u64 peer = ioread64(&sndev->peer_shared->magic);

		if ((peer & 0xFFFFFFFF) == SWITCHTEC_NTB_MAGIC)
			link_sta = peer >> 32;
		else
			link_sta = 0;
	}

	sndev->link_is_up = link_sta;
	switchtec_ntb_set_link_speed(sndev);

	if (link_sta != old) {
		switchtec_ntb_send_msg(sndev, LINK_MESSAGE, MSG_CHECK_LINK);
		ntb_link_event(&sndev->ntb);
		dev_info(&sndev->stdev->dev, "ntb link %s\n",
			 link_sta ? "up" : "down");

		if (link_sta)
			crosslink_init_dbmsgs(sndev);
	}
}

static void check_link_status_work(struct work_struct *work)
{
	struct switchtec_ntb *sndev;

	sndev = container_of(work, struct switchtec_ntb,
			     check_link_status_work);

	if (sndev->link_force_down) {
		sndev->link_force_down = false;
		switchtec_ntb_reinit_peer(sndev);

		if (sndev->link_is_up) {
			sndev->link_is_up = 0;
			ntb_link_event(&sndev->ntb);
			dev_info(&sndev->stdev->dev, "ntb link forced down\n");
		}

		return;
	}

	switchtec_ntb_link_status_update(sndev);
}

static void switchtec_ntb_check_link(struct switchtec_ntb *sndev,
				      enum switchtec_msg msg)
{
	if (msg == MSG_LINK_FORCE_DOWN)
		sndev->link_force_down = true;

	schedule_work(&sndev->check_link_status_work);
}

static void switchtec_ntb_link_notification(struct switchtec_dev *stdev)
{
	struct switchtec_ntb *sndev = stdev->sndev;

	switchtec_ntb_check_link(sndev, MSG_CHECK_LINK);
}

static u64 switchtec_ntb_link_is_up(struct ntb_dev *ntb,
				    enum ntb_speed *speed,
				    enum ntb_width *width)
{
	struct switchtec_ntb *sndev = ntb_sndev(ntb);

	if (speed)
		*speed = sndev->link_speed;
	if (width)
		*width = sndev->link_width;

	return sndev->link_is_up;
}

static int switchtec_ntb_link_enable(struct ntb_dev *ntb,
				     enum ntb_speed max_speed,
				     enum ntb_width max_width)
{
	struct switchtec_ntb *sndev = ntb_sndev(ntb);

	dev_dbg(&sndev->stdev->dev, "enabling link\n");

	sndev->self_shared->link_sta = 1;
	switchtec_ntb_send_msg(sndev, LINK_MESSAGE, MSG_LINK_UP);

	switchtec_ntb_link_status_update(sndev);

	return 0;
}

static int switchtec_ntb_link_disable(struct ntb_dev *ntb)
{
	struct switchtec_ntb *sndev = ntb_sndev(ntb);

	dev_dbg(&sndev->stdev->dev, "disabling link\n");

	sndev->self_shared->link_sta = 0;
	switchtec_ntb_send_msg(sndev, LINK_MESSAGE, MSG_LINK_DOWN);

	switchtec_ntb_link_status_update(sndev);

	return 0;
}

static u64 switchtec_ntb_db_valid_mask(struct ntb_dev *ntb)
{
	struct switchtec_ntb *sndev = ntb_sndev(ntb);

	return sndev->db_valid_mask;
}

static int switchtec_ntb_db_vector_count(struct ntb_dev *ntb)
{
	return 1;
}

static u64 switchtec_ntb_db_vector_mask(struct ntb_dev *ntb, int db_vector)
{
	struct switchtec_ntb *sndev = ntb_sndev(ntb);

	if (db_vector < 0 || db_vector > 1)
		return 0;

	return sndev->db_valid_mask;
}

static u64 switchtec_ntb_db_read(struct ntb_dev *ntb)
{
	u64 ret;
	struct switchtec_ntb *sndev = ntb_sndev(ntb);

	ret = ioread64(&sndev->mmio_self_dbmsg->idb) >> sndev->db_shift;

	return ret & sndev->db_valid_mask;
}

static int switchtec_ntb_db_clear(struct ntb_dev *ntb, u64 db_bits)
{
	struct switchtec_ntb *sndev = ntb_sndev(ntb);

	iowrite64(db_bits << sndev->db_shift, &sndev->mmio_self_dbmsg->idb);

	return 0;
}

static int switchtec_ntb_db_set_mask(struct ntb_dev *ntb, u64 db_bits)
{
	unsigned long irqflags;
	struct switchtec_ntb *sndev = ntb_sndev(ntb);

	if (db_bits & ~sndev->db_valid_mask)
		return -EINVAL;

	spin_lock_irqsave(&sndev->db_mask_lock, irqflags);

	sndev->db_mask |= db_bits << sndev->db_shift;
	iowrite64(~sndev->db_mask, &sndev->mmio_self_dbmsg->idb_mask);

	spin_unlock_irqrestore(&sndev->db_mask_lock, irqflags);

	return 0;
}

static int switchtec_ntb_db_clear_mask(struct ntb_dev *ntb, u64 db_bits)
{
	unsigned long irqflags;
	struct switchtec_ntb *sndev = ntb_sndev(ntb);

	if (db_bits & ~sndev->db_valid_mask)
		return -EINVAL;

	spin_lock_irqsave(&sndev->db_mask_lock, irqflags);

	sndev->db_mask &= ~(db_bits << sndev->db_shift);
	iowrite64(~sndev->db_mask, &sndev->mmio_self_dbmsg->idb_mask);

	spin_unlock_irqrestore(&sndev->db_mask_lock, irqflags);

	return 0;
}

static u64 switchtec_ntb_db_read_mask(struct ntb_dev *ntb)
{
	struct switchtec_ntb *sndev = ntb_sndev(ntb);

	return (sndev->db_mask >> sndev->db_shift) & sndev->db_valid_mask;
}

static int switchtec_ntb_peer_db_addr(struct ntb_dev *ntb,
				      phys_addr_t *db_addr,
				      resource_size_t *db_size,
				      u64 *db_data,
				      int db_bit)
{
	struct switchtec_ntb *sndev = ntb_sndev(ntb);
	unsigned long offset;

	if (unlikely(db_bit >= BITS_PER_LONG_LONG))
		return -EINVAL;

	offset = (unsigned long)sndev->mmio_peer_dbmsg->odb -
		(unsigned long)sndev->stdev->mmio;

	offset += sndev->db_shift / 8;

	if (db_addr)
		*db_addr = pci_resource_start(ntb->pdev, 0) + offset;
	if (db_size)
		*db_size = sizeof(u32);
	if (db_data)
		*db_data = BIT_ULL(db_bit) << sndev->db_peer_shift;

	return 0;
}

static int switchtec_ntb_peer_db_set(struct ntb_dev *ntb, u64 db_bits)
{
	struct switchtec_ntb *sndev = ntb_sndev(ntb);

	iowrite64(db_bits << sndev->db_peer_shift,
		  &sndev->mmio_peer_dbmsg->odb);

	return 0;
}

static int switchtec_ntb_spad_count(struct ntb_dev *ntb)
{
	struct switchtec_ntb *sndev = ntb_sndev(ntb);

	return ARRAY_SIZE(sndev->self_shared->spad);
}

static u32 switchtec_ntb_spad_read(struct ntb_dev *ntb, int idx)
{
	struct switchtec_ntb *sndev = ntb_sndev(ntb);

	if (idx < 0 || idx >= ARRAY_SIZE(sndev->self_shared->spad))
		return 0;

	if (!sndev->self_shared)
		return 0;

	return sndev->self_shared->spad[idx];
}

static int switchtec_ntb_spad_write(struct ntb_dev *ntb, int idx, u32 val)
{
	struct switchtec_ntb *sndev = ntb_sndev(ntb);

	if (idx < 0 || idx >= ARRAY_SIZE(sndev->self_shared->spad))
		return -EINVAL;

	if (!sndev->self_shared)
		return -EIO;

	sndev->self_shared->spad[idx] = val;

	return 0;
}

static u32 switchtec_ntb_peer_spad_read(struct ntb_dev *ntb, int pidx,
					int sidx)
{
	struct switchtec_ntb *sndev = ntb_sndev(ntb);

	if (pidx != NTB_DEF_PEER_IDX)
		return -EINVAL;

	if (sidx < 0 || sidx >= ARRAY_SIZE(sndev->peer_shared->spad))
		return 0;

	if (!sndev->peer_shared)
		return 0;

	return ioread32(&sndev->peer_shared->spad[sidx]);
}

static int switchtec_ntb_peer_spad_write(struct ntb_dev *ntb, int pidx,
					 int sidx, u32 val)
{
	struct switchtec_ntb *sndev = ntb_sndev(ntb);

	if (pidx != NTB_DEF_PEER_IDX)
		return -EINVAL;

	if (sidx < 0 || sidx >= ARRAY_SIZE(sndev->peer_shared->spad))
		return -EINVAL;

	if (!sndev->peer_shared)
		return -EIO;

	iowrite32(val, &sndev->peer_shared->spad[sidx]);

	return 0;
}

static int switchtec_ntb_peer_spad_addr(struct ntb_dev *ntb, int pidx,
					int sidx, phys_addr_t *spad_addr)
{
	struct switchtec_ntb *sndev = ntb_sndev(ntb);
	unsigned long offset;

	if (pidx != NTB_DEF_PEER_IDX)
		return -EINVAL;

	offset = (unsigned long)&sndev->peer_shared->spad[sidx] -
		(unsigned long)sndev->stdev->mmio;

	if (spad_addr)
		*spad_addr = pci_resource_start(ntb->pdev, 0) + offset;

	return 0;
}

static const struct ntb_dev_ops switchtec_ntb_ops = {
	.mw_count		= switchtec_ntb_mw_count,
	.mw_get_align		= switchtec_ntb_mw_get_align,
	.mw_set_trans		= switchtec_ntb_mw_set_trans,
	.peer_mw_count		= switchtec_ntb_peer_mw_count,
	.peer_mw_get_addr	= switchtec_ntb_peer_mw_get_addr,
	.link_is_up		= switchtec_ntb_link_is_up,
	.link_enable		= switchtec_ntb_link_enable,
	.link_disable		= switchtec_ntb_link_disable,
	.db_valid_mask		= switchtec_ntb_db_valid_mask,
	.db_vector_count	= switchtec_ntb_db_vector_count,
	.db_vector_mask		= switchtec_ntb_db_vector_mask,
	.db_read		= switchtec_ntb_db_read,
	.db_clear		= switchtec_ntb_db_clear,
	.db_set_mask		= switchtec_ntb_db_set_mask,
	.db_clear_mask		= switchtec_ntb_db_clear_mask,
	.db_read_mask		= switchtec_ntb_db_read_mask,
	.peer_db_addr		= switchtec_ntb_peer_db_addr,
	.peer_db_set		= switchtec_ntb_peer_db_set,
	.spad_count		= switchtec_ntb_spad_count,
	.spad_read		= switchtec_ntb_spad_read,
	.spad_write		= switchtec_ntb_spad_write,
	.peer_spad_read		= switchtec_ntb_peer_spad_read,
	.peer_spad_write	= switchtec_ntb_peer_spad_write,
	.peer_spad_addr		= switchtec_ntb_peer_spad_addr,
};

static int switchtec_ntb_init_sndev(struct switchtec_ntb *sndev)
{
	u64 tpart_vec;
	int self;
	u64 part_map;
	int bit;

	sndev->ntb.pdev = sndev->stdev->pdev;
	sndev->ntb.topo = NTB_TOPO_SWITCH;
	sndev->ntb.ops = &switchtec_ntb_ops;

	INIT_WORK(&sndev->check_link_status_work, check_link_status_work);
	sndev->link_force_down = false;

	sndev->self_partition = sndev->stdev->partition;

	sndev->mmio_ntb = sndev->stdev->mmio_ntb;

	self = sndev->self_partition;
	tpart_vec = ioread32(&sndev->mmio_ntb->ntp_info[self].target_part_high);
	tpart_vec <<= 32;
	tpart_vec |= ioread32(&sndev->mmio_ntb->ntp_info[self].target_part_low);

	part_map = ioread64(&sndev->mmio_ntb->ep_map);
	part_map &= ~(1 << sndev->self_partition);

	if (!ffs(tpart_vec)) {
		if (sndev->stdev->partition_count != 2) {
			dev_err(&sndev->stdev->dev,
				"ntb target partition not defined\n");
			return -ENODEV;
		}

		bit = ffs(part_map);
		if (!bit) {
			dev_err(&sndev->stdev->dev,
				"peer partition is not NT partition\n");
			return -ENODEV;
		}

		sndev->peer_partition = bit - 1;
	} else {
		if (ffs(tpart_vec) != fls(tpart_vec)) {
			dev_err(&sndev->stdev->dev,
				"ntb driver only supports 1 pair of 1-1 ntb mapping\n");
			return -ENODEV;
		}

		sndev->peer_partition = ffs(tpart_vec) - 1;
		if (!(part_map & (1ULL << sndev->peer_partition))) {
			dev_err(&sndev->stdev->dev,
				"ntb target partition is not NT partition\n");
			return -ENODEV;
		}
	}

	dev_dbg(&sndev->stdev->dev, "Partition ID %d of %d\n",
		sndev->self_partition, sndev->stdev->partition_count);

	sndev->mmio_ctrl = (void * __iomem)sndev->mmio_ntb +
		SWITCHTEC_NTB_REG_CTRL_OFFSET;
	sndev->mmio_dbmsg = (void * __iomem)sndev->mmio_ntb +
		SWITCHTEC_NTB_REG_DBMSG_OFFSET;

	sndev->mmio_self_ctrl = &sndev->mmio_ctrl[sndev->self_partition];
	sndev->mmio_peer_ctrl = &sndev->mmio_ctrl[sndev->peer_partition];
	sndev->mmio_self_dbmsg = &sndev->mmio_dbmsg[sndev->self_partition];
	sndev->mmio_peer_dbmsg = sndev->mmio_self_dbmsg;

	return 0;
}

static int config_rsvd_lut_win(struct switchtec_ntb *sndev,
			       struct ntb_ctrl_regs __iomem *ctl,
			       int lut_idx, int partition, u64 addr)
{
	int peer_bar = sndev->peer_direct_mw_to_bar[0];
	u32 ctl_val;
	int rc;

	rc = switchtec_ntb_part_op(sndev, ctl, NTB_CTRL_PART_OP_LOCK,
				   NTB_CTRL_PART_STATUS_LOCKED);
	if (rc)
		return rc;

	ctl_val = ioread32(&ctl->bar_entry[peer_bar].ctl);
	ctl_val &= 0xFF;
	ctl_val |= NTB_CTRL_BAR_LUT_WIN_EN;
	ctl_val |= ilog2(LUT_SIZE) << 8;
	ctl_val |= (sndev->nr_lut_mw - 1) << 14;
	iowrite32(ctl_val, &ctl->bar_entry[peer_bar].ctl);

	iowrite64((NTB_CTRL_LUT_EN | (partition << 1) | addr),
		  &ctl->lut_entry[lut_idx]);

	rc = switchtec_ntb_part_op(sndev, ctl, NTB_CTRL_PART_OP_CFG,
				   NTB_CTRL_PART_STATUS_NORMAL);
	if (rc) {
		u32 bar_error, lut_error;

		bar_error = ioread32(&ctl->bar_error);
		lut_error = ioread32(&ctl->lut_error);
		dev_err(&sndev->stdev->dev,
			"Error setting up reserved lut window: %08x / %08x\n",
			bar_error, lut_error);
		return rc;
	}

	return 0;
}

static int config_req_id_table(struct switchtec_ntb *sndev,
			       struct ntb_ctrl_regs __iomem *mmio_ctrl,
			       int *req_ids, int count)
{
	int i, rc = 0;
	u32 error;
	u32 proxy_id;

	if (ioread32(&mmio_ctrl->req_id_table_size) < count) {
		dev_err(&sndev->stdev->dev,
			"Not enough requester IDs available.\n");
		return -EFAULT;
	}

	rc = switchtec_ntb_part_op(sndev, mmio_ctrl,
				   NTB_CTRL_PART_OP_LOCK,
				   NTB_CTRL_PART_STATUS_LOCKED);
	if (rc)
		return rc;

	iowrite32(NTB_PART_CTRL_ID_PROT_DIS,
		  &mmio_ctrl->partition_ctrl);

	for (i = 0; i < count; i++) {
		iowrite32(req_ids[i] << 16 | NTB_CTRL_REQ_ID_EN,
			  &mmio_ctrl->req_id_table[i]);

		proxy_id = ioread32(&mmio_ctrl->req_id_table[i]);
		dev_dbg(&sndev->stdev->dev,
			"Requester ID %02X:%02X.%X -> BB:%02X.%X\n",
			req_ids[i] >> 8, (req_ids[i] >> 3) & 0x1F,
			req_ids[i] & 0x7, (proxy_id >> 4) & 0x1F,
			(proxy_id >> 1) & 0x7);
	}

	rc = switchtec_ntb_part_op(sndev, mmio_ctrl,
				   NTB_CTRL_PART_OP_CFG,
				   NTB_CTRL_PART_STATUS_NORMAL);

	if (rc == -EIO) {
		error = ioread32(&mmio_ctrl->req_id_error);
		dev_err(&sndev->stdev->dev,
			"Error setting up the requester ID table: %08x\n",
			error);
	}

	return 0;
}

static int crosslink_setup_mws(struct switchtec_ntb *sndev, int ntb_lut_idx,
			       u64 *mw_addrs, int mw_count)
{
	int rc, i;
	struct ntb_ctrl_regs __iomem *ctl = sndev->mmio_self_ctrl;
	u64 addr;
	size_t size, offset;
	int bar;
	int xlate_pos;
	u32 ctl_val;

	rc = switchtec_ntb_part_op(sndev, ctl, NTB_CTRL_PART_OP_LOCK,
				   NTB_CTRL_PART_STATUS_LOCKED);
	if (rc)
		return rc;

	for (i = 0; i < sndev->nr_lut_mw; i++) {
		if (i == ntb_lut_idx)
			continue;

		addr = mw_addrs[0] + LUT_SIZE * i;

		iowrite64((NTB_CTRL_LUT_EN | (sndev->peer_partition << 1) |
			   addr),
			  &ctl->lut_entry[i]);
	}

	sndev->nr_direct_mw = min_t(int, sndev->nr_direct_mw, mw_count);

	for (i = 0; i < sndev->nr_direct_mw; i++) {
		bar = sndev->direct_mw_to_bar[i];
		offset = (i == 0) ? LUT_SIZE * sndev->nr_lut_mw : 0;
		addr = mw_addrs[i] + offset;
		size = pci_resource_len(sndev->ntb.pdev, bar) - offset;
		xlate_pos = ilog2(size);

		if (offset && size > offset)
			size = offset;

		ctl_val = ioread32(&ctl->bar_entry[bar].ctl);
		ctl_val |= NTB_CTRL_BAR_DIR_WIN_EN;

		iowrite32(ctl_val, &ctl->bar_entry[bar].ctl);
		iowrite32(xlate_pos | (lower_32_bits(size) & 0xFFFFF000),
			  &ctl->bar_entry[bar].win_size);
		iowrite32(upper_32_bits(size), &ctl->bar_ext_entry[bar].win_size);
		iowrite64(sndev->peer_partition | addr,
			  &ctl->bar_entry[bar].xlate_addr);
	}

	rc = switchtec_ntb_part_op(sndev, ctl, NTB_CTRL_PART_OP_CFG,
				   NTB_CTRL_PART_STATUS_NORMAL);
	if (rc) {
		u32 bar_error, lut_error;

		bar_error = ioread32(&ctl->bar_error);
		lut_error = ioread32(&ctl->lut_error);
		dev_err(&sndev->stdev->dev,
			"Error setting up cross link windows: %08x / %08x\n",
			bar_error, lut_error);
		return rc;
	}

	return 0;
}

static int crosslink_setup_req_ids(struct switchtec_ntb *sndev,
	struct ntb_ctrl_regs __iomem *mmio_ctrl)
{
	int req_ids[16];
	int i;
	u32 proxy_id;

	for (i = 0; i < ARRAY_SIZE(req_ids); i++) {
		proxy_id = ioread32(&sndev->mmio_self_ctrl->req_id_table[i]);

		if (!(proxy_id & NTB_CTRL_REQ_ID_EN))
			break;

		req_ids[i] = ((proxy_id >> 1) & 0xFF);
	}

	return config_req_id_table(sndev, mmio_ctrl, req_ids, i);
}

/*
 * In crosslink configuration there is a virtual partition in the
 * middle of the two switches. The BARs in this partition have to be
 * enumerated and assigned addresses.
 */
static int crosslink_enum_partition(struct switchtec_ntb *sndev,
				    u64 *bar_addrs)
{
	struct part_cfg_regs __iomem *part_cfg =
		&sndev->stdev->mmio_part_cfg_all[sndev->peer_partition];
	u32 pff = ioread32(&part_cfg->vep_pff_inst_id);
	struct pff_csr_regs __iomem *mmio_pff =
		&sndev->stdev->mmio_pff_csr[pff];
	const u64 bar_space = 0x1000000000LL;
	u64 bar_addr;
	int bar_cnt = 0;
	int i;

	iowrite16(0x6, &mmio_pff->pcicmd);

	for (i = 0; i < ARRAY_SIZE(mmio_pff->pci_bar64); i++) {
		iowrite64(bar_space * i, &mmio_pff->pci_bar64[i]);
		bar_addr = ioread64(&mmio_pff->pci_bar64[i]);
		bar_addr &= ~0xf;

		dev_dbg(&sndev->stdev->dev,
			"Crosslink BAR%d addr: %llx\n",
			i*2, bar_addr);

		if (bar_addr != bar_space * i)
			continue;

		bar_addrs[bar_cnt++] = bar_addr;
	}

	return bar_cnt;
}

static int switchtec_ntb_init_crosslink(struct switchtec_ntb *sndev)
{
	int rc;
	int bar = sndev->direct_mw_to_bar[0];
	const int ntb_lut_idx = 1;
	u64 bar_addrs[6];
	u64 addr;
	int offset;
	int bar_cnt;

	if (!crosslink_is_enabled(sndev))
		return 0;

	dev_info(&sndev->stdev->dev, "Using crosslink configuration\n");
	sndev->ntb.topo = NTB_TOPO_CROSSLINK;

	bar_cnt = crosslink_enum_partition(sndev, bar_addrs);
	if (bar_cnt < sndev->nr_direct_mw + 1) {
		dev_err(&sndev->stdev->dev,
			"Error enumerating crosslink partition\n");
		return -EINVAL;
	}

	addr = (bar_addrs[0] + SWITCHTEC_GAS_NTB_OFFSET +
		SWITCHTEC_NTB_REG_DBMSG_OFFSET +
		sizeof(struct ntb_dbmsg_regs) * sndev->peer_partition);

	offset = addr & (LUT_SIZE - 1);
	addr -= offset;

	rc = config_rsvd_lut_win(sndev, sndev->mmio_self_ctrl, ntb_lut_idx,
				 sndev->peer_partition, addr);
	if (rc)
		return rc;

	rc = crosslink_setup_mws(sndev, ntb_lut_idx, &bar_addrs[1],
				 bar_cnt - 1);
	if (rc)
		return rc;

	rc = crosslink_setup_req_ids(sndev, sndev->mmio_peer_ctrl);
	if (rc)
		return rc;

	sndev->mmio_xlink_win = pci_iomap_range(sndev->stdev->pdev, bar,
						LUT_SIZE, LUT_SIZE);
	if (!sndev->mmio_xlink_win) {
		rc = -ENOMEM;
		return rc;
	}

	sndev->mmio_peer_dbmsg = sndev->mmio_xlink_win + offset;
	sndev->nr_rsvd_luts++;

	crosslink_init_dbmsgs(sndev);

	return 0;
}

static void switchtec_ntb_deinit_crosslink(struct switchtec_ntb *sndev)
{
	if (sndev->mmio_xlink_win)
		pci_iounmap(sndev->stdev->pdev, sndev->mmio_xlink_win);
}

static int map_bars(int *map, struct ntb_ctrl_regs __iomem *ctrl)
{
	int i;
	int cnt = 0;

	for (i = 0; i < ARRAY_SIZE(ctrl->bar_entry); i++) {
		u32 r = ioread32(&ctrl->bar_entry[i].ctl);

		if (r & NTB_CTRL_BAR_VALID)
			map[cnt++] = i;
	}

	return cnt;
}

static void switchtec_ntb_init_mw(struct switchtec_ntb *sndev)
{
	sndev->nr_direct_mw = map_bars(sndev->direct_mw_to_bar,
				       sndev->mmio_self_ctrl);

	sndev->nr_lut_mw = ioread16(&sndev->mmio_self_ctrl->lut_table_entries);
	sndev->nr_lut_mw = rounddown_pow_of_two(sndev->nr_lut_mw);

	dev_dbg(&sndev->stdev->dev, "MWs: %d direct, %d lut\n",
		sndev->nr_direct_mw, sndev->nr_lut_mw);

	sndev->peer_nr_direct_mw = map_bars(sndev->peer_direct_mw_to_bar,
					    sndev->mmio_peer_ctrl);

	sndev->peer_nr_lut_mw =
		ioread16(&sndev->mmio_peer_ctrl->lut_table_entries);
	sndev->peer_nr_lut_mw = rounddown_pow_of_two(sndev->peer_nr_lut_mw);

	dev_dbg(&sndev->stdev->dev, "Peer MWs: %d direct, %d lut\n",
		sndev->peer_nr_direct_mw, sndev->peer_nr_lut_mw);

}

/*
 * There are 64 doorbells in the switch hardware but this is
 * shared among all partitions. So we must split them in half
 * (32 for each partition). However, the message interrupts are
 * also shared with the top 4 doorbells so we just limit this to
 * 28 doorbells per partition.
 *
 * In crosslink mode, each side has it's own dbmsg register so
 * they can each use all 60 of the available doorbells.
 */
static void switchtec_ntb_init_db(struct switchtec_ntb *sndev)
{
	sndev->db_mask = 0x0FFFFFFFFFFFFFFFULL;

	if (sndev->mmio_peer_dbmsg != sndev->mmio_self_dbmsg) {
		sndev->db_shift = 0;
		sndev->db_peer_shift = 0;
		sndev->db_valid_mask = sndev->db_mask;
	} else if (sndev->self_partition < sndev->peer_partition) {
		sndev->db_shift = 0;
		sndev->db_peer_shift = 32;
		sndev->db_valid_mask = 0x0FFFFFFF;
	} else {
		sndev->db_shift = 32;
		sndev->db_peer_shift = 0;
		sndev->db_valid_mask = 0x0FFFFFFF;
	}

	iowrite64(~sndev->db_mask, &sndev->mmio_self_dbmsg->idb_mask);
	iowrite64(sndev->db_valid_mask << sndev->db_peer_shift,
		  &sndev->mmio_peer_dbmsg->odb_mask);

	dev_dbg(&sndev->stdev->dev, "dbs: shift %d/%d, mask %016llx\n",
		sndev->db_shift, sndev->db_peer_shift, sndev->db_valid_mask);
}

static void switchtec_ntb_init_msgs(struct switchtec_ntb *sndev)
{
	int i;
	u32 msg_map = 0;

	for (i = 0; i < ARRAY_SIZE(sndev->mmio_self_dbmsg->imsg); i++) {
		int m = i | sndev->peer_partition << 2;

		msg_map |= m << i * 8;
	}

	iowrite32(msg_map, &sndev->mmio_self_dbmsg->msg_map);

	for (i = 0; i < ARRAY_SIZE(sndev->mmio_self_dbmsg->imsg); i++)
		iowrite64(NTB_DBMSG_IMSG_STATUS | NTB_DBMSG_IMSG_MASK,
			  &sndev->mmio_self_dbmsg->imsg[i]);
}

static int
switchtec_ntb_init_req_id_table(struct switchtec_ntb *sndev)
{
	int req_ids[2];

	/*
	 * Root Complex Requester ID (which is 0:00.0)
	 */
	req_ids[0] = 0;

	/*
	 * Host Bridge Requester ID (as read from the mmap address)
	 */
	req_ids[1] = ioread16(&sndev->mmio_ntb->requester_id);

	return config_req_id_table(sndev, sndev->mmio_self_ctrl, req_ids,
				   ARRAY_SIZE(req_ids));
}

static void switchtec_ntb_init_shared(struct switchtec_ntb *sndev)
{
	int i;

	memset(sndev->self_shared, 0, LUT_SIZE);
	sndev->self_shared->magic = SWITCHTEC_NTB_MAGIC;
	sndev->self_shared->partition_id = sndev->stdev->partition;

	for (i = 0; i < sndev->nr_direct_mw; i++) {
		int bar = sndev->direct_mw_to_bar[i];
		resource_size_t sz = pci_resource_len(sndev->stdev->pdev, bar);

		if (i == 0)
			sz = min_t(resource_size_t, sz,
				   LUT_SIZE * sndev->nr_lut_mw);

		sndev->self_shared->mw_sizes[i] = sz;
	}

	for (i = 0; i < sndev->nr_lut_mw; i++) {
		int idx = sndev->nr_direct_mw + i;

		sndev->self_shared->mw_sizes[idx] = LUT_SIZE;
	}
}

static int switchtec_ntb_init_shared_mw(struct switchtec_ntb *sndev)
{
	int self_bar = sndev->direct_mw_to_bar[0];
	int rc;

	sndev->nr_rsvd_luts++;
	sndev->self_shared = dma_alloc_coherent(&sndev->stdev->pdev->dev,
						LUT_SIZE,
						&sndev->self_shared_dma,
						GFP_KERNEL);
	if (!sndev->self_shared) {
		dev_err(&sndev->stdev->dev,
			"unable to allocate memory for shared mw\n");
		return -ENOMEM;
	}

	switchtec_ntb_init_shared(sndev);

	rc = config_rsvd_lut_win(sndev, sndev->mmio_peer_ctrl, 0,
				 sndev->self_partition,
				 sndev->self_shared_dma);
	if (rc)
		goto unalloc_and_exit;

	sndev->peer_shared = pci_iomap(sndev->stdev->pdev, self_bar, LUT_SIZE);
	if (!sndev->peer_shared) {
		rc = -ENOMEM;
		goto unalloc_and_exit;
	}

	dev_dbg(&sndev->stdev->dev, "Shared MW Ready\n");
	return 0;

unalloc_and_exit:
	dma_free_coherent(&sndev->stdev->pdev->dev, LUT_SIZE,
			  sndev->self_shared, sndev->self_shared_dma);

	return rc;
}

static void switchtec_ntb_deinit_shared_mw(struct switchtec_ntb *sndev)
{
	if (sndev->peer_shared)
		pci_iounmap(sndev->stdev->pdev, sndev->peer_shared);

	if (sndev->self_shared)
		dma_free_coherent(&sndev->stdev->pdev->dev, LUT_SIZE,
				  sndev->self_shared,
				  sndev->self_shared_dma);
	sndev->nr_rsvd_luts--;
}

static irqreturn_t switchtec_ntb_doorbell_isr(int irq, void *dev)
{
	struct switchtec_ntb *sndev = dev;

	dev_dbg(&sndev->stdev->dev, "doorbell\n");

	ntb_db_event(&sndev->ntb, 0);

	return IRQ_HANDLED;
}

static irqreturn_t switchtec_ntb_message_isr(int irq, void *dev)
{
	int i;
	struct switchtec_ntb *sndev = dev;

	for (i = 0; i < ARRAY_SIZE(sndev->mmio_self_dbmsg->imsg); i++) {
		u64 msg = ioread64(&sndev->mmio_self_dbmsg->imsg[i]);

		if (msg & NTB_DBMSG_IMSG_STATUS) {
			dev_dbg(&sndev->stdev->dev, "message: %d %08x\n",
				i, (u32)msg);
			iowrite8(1, &sndev->mmio_self_dbmsg->imsg[i].status);

			if (i == LINK_MESSAGE)
				switchtec_ntb_check_link(sndev, msg);
		}
	}

	return IRQ_HANDLED;
}

static int switchtec_ntb_init_db_msg_irq(struct switchtec_ntb *sndev)
{
	int i;
	int rc;
	int doorbell_irq = 0;
	int message_irq = 0;
	int event_irq;
	int idb_vecs = sizeof(sndev->mmio_self_dbmsg->idb_vec_map);

	event_irq = ioread32(&sndev->stdev->mmio_part_cfg->vep_vector_number);

	while (doorbell_irq == event_irq)
		doorbell_irq++;
	while (message_irq == doorbell_irq ||
	       message_irq == event_irq)
		message_irq++;

	dev_dbg(&sndev->stdev->dev, "irqs - event: %d, db: %d, msgs: %d\n",
		event_irq, doorbell_irq, message_irq);

	for (i = 0; i < idb_vecs - 4; i++)
		iowrite8(doorbell_irq,
			 &sndev->mmio_self_dbmsg->idb_vec_map[i]);

	for (; i < idb_vecs; i++)
		iowrite8(message_irq,
			 &sndev->mmio_self_dbmsg->idb_vec_map[i]);

	sndev->doorbell_irq = pci_irq_vector(sndev->stdev->pdev, doorbell_irq);
	sndev->message_irq = pci_irq_vector(sndev->stdev->pdev, message_irq);

	rc = request_irq(sndev->doorbell_irq,
			 switchtec_ntb_doorbell_isr, 0,
			 "switchtec_ntb_doorbell", sndev);
	if (rc)
		return rc;

	rc = request_irq(sndev->message_irq,
			 switchtec_ntb_message_isr, 0,
			 "switchtec_ntb_message", sndev);
	if (rc) {
		free_irq(sndev->doorbell_irq, sndev);
		return rc;
	}

	return 0;
}

static void switchtec_ntb_deinit_db_msg_irq(struct switchtec_ntb *sndev)
{
	free_irq(sndev->doorbell_irq, sndev);
	free_irq(sndev->message_irq, sndev);
}

static int switchtec_ntb_reinit_peer(struct switchtec_ntb *sndev)
{
	int rc;

	if (crosslink_is_enabled(sndev))
		return 0;

	dev_info(&sndev->stdev->dev, "reinitialize shared memory window\n");
	rc = config_rsvd_lut_win(sndev, sndev->mmio_peer_ctrl, 0,
				 sndev->self_partition,
				 sndev->self_shared_dma);
	return rc;
}

static int switchtec_ntb_add(struct device *dev,
			     struct class_interface *class_intf)
{
	struct switchtec_dev *stdev = to_stdev(dev);
	struct switchtec_ntb *sndev;
	int rc;

	stdev->sndev = NULL;

	if (stdev->pdev->class != (PCI_CLASS_BRIDGE_OTHER << 8))
		return -ENODEV;

	sndev = kzalloc_node(sizeof(*sndev), GFP_KERNEL, dev_to_node(dev));
	if (!sndev)
		return -ENOMEM;

	sndev->stdev = stdev;
	rc = switchtec_ntb_init_sndev(sndev);
	if (rc)
		goto free_and_exit;

	switchtec_ntb_init_mw(sndev);

	rc = switchtec_ntb_init_req_id_table(sndev);
	if (rc)
		goto free_and_exit;

	rc = switchtec_ntb_init_crosslink(sndev);
	if (rc)
		goto free_and_exit;

	switchtec_ntb_init_db(sndev);
	switchtec_ntb_init_msgs(sndev);

	rc = switchtec_ntb_init_shared_mw(sndev);
	if (rc)
		goto deinit_crosslink;

	rc = switchtec_ntb_init_db_msg_irq(sndev);
	if (rc)
		goto deinit_shared_and_exit;

	/*
	 * If this host crashed, the other host may think the link is
	 * still up. Tell them to force it down (it will go back up
	 * once we register the ntb device).
	 */
	switchtec_ntb_send_msg(sndev, LINK_MESSAGE, MSG_LINK_FORCE_DOWN);

	rc = ntb_register_device(&sndev->ntb);
	if (rc)
		goto deinit_and_exit;

	stdev->sndev = sndev;
	stdev->link_notifier = switchtec_ntb_link_notification;
	dev_info(dev, "NTB device registered\n");

	return 0;

deinit_and_exit:
	switchtec_ntb_deinit_db_msg_irq(sndev);
deinit_shared_and_exit:
	switchtec_ntb_deinit_shared_mw(sndev);
deinit_crosslink:
	switchtec_ntb_deinit_crosslink(sndev);
free_and_exit:
	kfree(sndev);
	dev_err(dev, "failed to register ntb device: %d\n", rc);
	return rc;
}

static void switchtec_ntb_remove(struct device *dev,
				 struct class_interface *class_intf)
{
	struct switchtec_dev *stdev = to_stdev(dev);
	struct switchtec_ntb *sndev = stdev->sndev;

	if (!sndev)
		return;

	stdev->link_notifier = NULL;
	stdev->sndev = NULL;
	ntb_unregister_device(&sndev->ntb);
	switchtec_ntb_deinit_db_msg_irq(sndev);
	switchtec_ntb_deinit_shared_mw(sndev);
	switchtec_ntb_deinit_crosslink(sndev);
	kfree(sndev);
	dev_info(dev, "ntb device unregistered\n");
}

static struct class_interface switchtec_interface  = {
	.add_dev = switchtec_ntb_add,
	.remove_dev = switchtec_ntb_remove,
};

static int __init switchtec_ntb_init(void)
{
	switchtec_interface.class = switchtec_class;
	return class_interface_register(&switchtec_interface);
}
module_init(switchtec_ntb_init);

static void __exit switchtec_ntb_exit(void)
{
	class_interface_unregister(&switchtec_interface);
}
module_exit(switchtec_ntb_exit);