1 files changed, 843 insertions, 0 deletions

diff --git a/drivers/net/ethernet/fungible/funcore/fun_dev.c b/drivers/net/ethernet/fungible/funcore/fun_dev.c
new file mode 100644
index 000000000000..fb5120d90f26
--- /dev/null
+++ b/drivers/net/ethernet/fungible/funcore/fun_dev.c
@@ -0,0 +1,843 @@
+// SPDX-License-Identifier: (GPL-2.0-only OR BSD-3-Clause)
+
+#include <linux/aer.h>
+#include <linux/bitmap.h>
+#include <linux/delay.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/io-64-nonatomic-lo-hi.h>
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <linux/nvme.h>
+#include <linux/pci.h>
+#include <linux/wait.h>
+#include <linux/sched/signal.h>
+
+#include "fun_queue.h"
+#include "fun_dev.h"
+
+#define FUN_ADMIN_CMD_TO_MS 3000
+
+enum {
+	AQA_ASQS_SHIFT = 0,
+	AQA_ACQS_SHIFT = 16,
+	AQA_MIN_QUEUE_SIZE = 2,
+	AQA_MAX_QUEUE_SIZE = 4096
+};
+
+/* context for admin commands */
+struct fun_cmd_ctx {
+	fun_admin_callback_t cb;  /* callback to invoke on completion */
+	void *cb_data;            /* user data provided to callback */
+	int cpu;                  /* CPU where the cmd's tag was allocated */
+};
+
+/* Context for synchronous admin commands. */
+struct fun_sync_cmd_ctx {
+	struct completion compl;
+	u8 *rsp_buf;              /* caller provided response buffer */
+	unsigned int rsp_len;     /* response buffer size */
+	u8 rsp_status;            /* command response status */
+};
+
+/* Wait for the CSTS.RDY bit to match @enabled. */
+static int fun_wait_ready(struct fun_dev *fdev, bool enabled)
+{
+	unsigned int cap_to = NVME_CAP_TIMEOUT(fdev->cap_reg);
+	u32 bit = enabled ? NVME_CSTS_RDY : 0;
+	unsigned long deadline;
+
+	deadline = ((cap_to + 1) * HZ / 2) + jiffies; /* CAP.TO is in 500ms */
+
+	for (;;) {
+		u32 csts = readl(fdev->bar + NVME_REG_CSTS);
+
+		if (csts == ~0) {
+			dev_err(fdev->dev, "CSTS register read %#x\n", csts);
+			return -EIO;
+		}
+
+		if ((csts & NVME_CSTS_RDY) == bit)
+			return 0;
+
+		if (time_is_before_jiffies(deadline))
+			break;
+
+		msleep(100);
+	}
+
+	dev_err(fdev->dev,
+		"Timed out waiting for device to indicate RDY %u; aborting %s\n",
+		enabled, enabled ? "initialization" : "reset");
+	return -ETIMEDOUT;
+}
+
+/* Check CSTS and return an error if it is unreadable or has unexpected
+ * RDY value.
+ */
+static int fun_check_csts_rdy(struct fun_dev *fdev, unsigned int expected_rdy)
+{
+	u32 csts = readl(fdev->bar + NVME_REG_CSTS);
+	u32 actual_rdy = csts & NVME_CSTS_RDY;
+
+	if (csts == ~0) {
+		dev_err(fdev->dev, "CSTS register read %#x\n", csts);
+		return -EIO;
+	}
+	if (actual_rdy != expected_rdy) {
+		dev_err(fdev->dev, "Unexpected CSTS RDY %u\n", actual_rdy);
+		return -EINVAL;
+	}
+	return 0;
+}
+
+/* Check that CSTS RDY has the expected value. Then write a new value to the CC
+ * register and wait for CSTS RDY to match the new CC ENABLE state.
+ */
+static int fun_update_cc_enable(struct fun_dev *fdev, unsigned int initial_rdy)
+{
+	int rc = fun_check_csts_rdy(fdev, initial_rdy);
+
+	if (rc)
+		return rc;
+	writel(fdev->cc_reg, fdev->bar + NVME_REG_CC);
+	return fun_wait_ready(fdev, !!(fdev->cc_reg & NVME_CC_ENABLE));
+}
+
+static int fun_disable_ctrl(struct fun_dev *fdev)
+{
+	fdev->cc_reg &= ~(NVME_CC_SHN_MASK | NVME_CC_ENABLE);
+	return fun_update_cc_enable(fdev, 1);
+}
+
+static int fun_enable_ctrl(struct fun_dev *fdev, u32 admin_cqesz_log2,
+			   u32 admin_sqesz_log2)
+{
+	fdev->cc_reg = (admin_cqesz_log2 << NVME_CC_IOCQES_SHIFT) |
+		       (admin_sqesz_log2 << NVME_CC_IOSQES_SHIFT) |
+		       ((PAGE_SHIFT - 12) << NVME_CC_MPS_SHIFT) |
+		       NVME_CC_ENABLE;
+
+	return fun_update_cc_enable(fdev, 0);
+}
+
+static int fun_map_bars(struct fun_dev *fdev, const char *name)
+{
+	struct pci_dev *pdev = to_pci_dev(fdev->dev);
+	int err;
+
+	err = pci_request_mem_regions(pdev, name);
+	if (err) {
+		dev_err(&pdev->dev,
+			"Couldn't get PCI memory resources, err %d\n", err);
+		return err;
+	}
+
+	fdev->bar = pci_ioremap_bar(pdev, 0);
+	if (!fdev->bar) {
+		dev_err(&pdev->dev, "Couldn't map BAR 0\n");
+		pci_release_mem_regions(pdev);
+		return -ENOMEM;
+	}
+
+	return 0;
+}
+
+static void fun_unmap_bars(struct fun_dev *fdev)
+{
+	struct pci_dev *pdev = to_pci_dev(fdev->dev);
+
+	if (fdev->bar) {
+		iounmap(fdev->bar);
+		fdev->bar = NULL;
+		pci_release_mem_regions(pdev);
+	}
+}
+
+static int fun_set_dma_masks(struct device *dev)
+{
+	int err;
+
+	err = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(64));
+	if (err)
+		dev_err(dev, "DMA mask configuration failed, err %d\n", err);
+	return err;
+}
+
+static irqreturn_t fun_admin_irq(int irq, void *data)
+{
+	struct fun_queue *funq = data;
+
+	return fun_process_cq(funq, 0) ? IRQ_HANDLED : IRQ_NONE;
+}
+
+static void fun_complete_admin_cmd(struct fun_queue *funq, void *data,
+				   void *entry, const struct fun_cqe_info *info)
+{
+	const struct fun_admin_rsp_common *rsp_common = entry;
+	struct fun_dev *fdev = funq->fdev;
+	struct fun_cmd_ctx *cmd_ctx;
+	int cpu;
+	u16 cid;
+
+	if (info->sqhd == cpu_to_be16(0xffff)) {
+		dev_dbg(fdev->dev, "adminq event");
+		if (fdev->adminq_cb)
+			fdev->adminq_cb(fdev, entry);
+		return;
+	}
+
+	cid = be16_to_cpu(rsp_common->cid);
+	dev_dbg(fdev->dev, "admin CQE cid %u, op %u, ret %u\n", cid,
+		rsp_common->op, rsp_common->ret);
+
+	cmd_ctx = &fdev->cmd_ctx[cid];
+	if (cmd_ctx->cpu < 0) {
+		dev_err(fdev->dev,
+			"admin CQE with CID=%u, op=%u does not match a pending command\n",
+			cid, rsp_common->op);
+		return;
+	}
+
+	if (cmd_ctx->cb)
+		cmd_ctx->cb(fdev, entry, xchg(&cmd_ctx->cb_data, NULL));
+
+	cpu = cmd_ctx->cpu;
+	cmd_ctx->cpu = -1;
+	sbitmap_queue_clear(&fdev->admin_sbq, cid, cpu);
+}
+
+static int fun_init_cmd_ctx(struct fun_dev *fdev, unsigned int ntags)
+{
+	unsigned int i;
+
+	fdev->cmd_ctx = kvcalloc(ntags, sizeof(*fdev->cmd_ctx), GFP_KERNEL);
+	if (!fdev->cmd_ctx)
+		return -ENOMEM;
+
+	for (i = 0; i < ntags; i++)
+		fdev->cmd_ctx[i].cpu = -1;
+
+	return 0;
+}
+
+/* Allocate and enable an admin queue and assign it the first IRQ vector. */
+static int fun_enable_admin_queue(struct fun_dev *fdev,
+				  const struct fun_dev_params *areq)
+{
+	struct fun_queue_alloc_req qreq = {
+		.cqe_size_log2 = areq->cqe_size_log2,
+		.sqe_size_log2 = areq->sqe_size_log2,
+		.cq_depth = areq->cq_depth,
+		.sq_depth = areq->sq_depth,
+		.rq_depth = areq->rq_depth,
+	};
+	unsigned int ntags = areq->sq_depth - 1;
+	struct fun_queue *funq;
+	int rc;
+
+	if (fdev->admin_q)
+		return -EEXIST;
+
+	if (areq->sq_depth < AQA_MIN_QUEUE_SIZE ||
+	    areq->sq_depth > AQA_MAX_QUEUE_SIZE ||
+	    areq->cq_depth < AQA_MIN_QUEUE_SIZE ||
+	    areq->cq_depth > AQA_MAX_QUEUE_SIZE)
+		return -EINVAL;
+
+	fdev->admin_q = fun_alloc_queue(fdev, 0, &qreq);
+	if (!fdev->admin_q)
+		return -ENOMEM;
+
+	rc = fun_init_cmd_ctx(fdev, ntags);
+	if (rc)
+		goto free_q;
+
+	rc = sbitmap_queue_init_node(&fdev->admin_sbq, ntags, -1, false,
+				     GFP_KERNEL, dev_to_node(fdev->dev));
+	if (rc)
+		goto free_cmd_ctx;
+
+	funq = fdev->admin_q;
+	funq->cq_vector = 0;
+	rc = fun_request_irq(funq, dev_name(fdev->dev), fun_admin_irq, funq);
+	if (rc)
+		goto free_sbq;
+
+	fun_set_cq_callback(funq, fun_complete_admin_cmd, NULL);
+	fdev->adminq_cb = areq->event_cb;
+
+	writel((funq->sq_depth - 1) << AQA_ASQS_SHIFT |
+	       (funq->cq_depth - 1) << AQA_ACQS_SHIFT,
+	       fdev->bar + NVME_REG_AQA);
+
+	writeq(funq->sq_dma_addr, fdev->bar + NVME_REG_ASQ);
+	writeq(funq->cq_dma_addr, fdev->bar + NVME_REG_ACQ);
+
+	rc = fun_enable_ctrl(fdev, areq->cqe_size_log2, areq->sqe_size_log2);
+	if (rc)
+		goto free_irq;
+
+	if (areq->rq_depth) {
+		rc = fun_create_rq(funq);
+		if (rc)
+			goto disable_ctrl;
+
+		funq_rq_post(funq);
+	}
+
+	return 0;
+
+disable_ctrl:
+	fun_disable_ctrl(fdev);
+free_irq:
+	fun_free_irq(funq);
+free_sbq:
+	sbitmap_queue_free(&fdev->admin_sbq);
+free_cmd_ctx:
+	kvfree(fdev->cmd_ctx);
+	fdev->cmd_ctx = NULL;
+free_q:
+	fun_free_queue(fdev->admin_q);
+	fdev->admin_q = NULL;
+	return rc;
+}
+
+static void fun_disable_admin_queue(struct fun_dev *fdev)
+{
+	struct fun_queue *admq = fdev->admin_q;
+
+	if (!admq)
+		return;
+
+	fun_disable_ctrl(fdev);
+
+	fun_free_irq(admq);
+	__fun_process_cq(admq, 0);
+
+	sbitmap_queue_free(&fdev->admin_sbq);
+
+	kvfree(fdev->cmd_ctx);
+	fdev->cmd_ctx = NULL;
+
+	fun_free_queue(admq);
+	fdev->admin_q = NULL;
+}
+
+/* Return %true if the admin queue has stopped servicing commands as can be
+ * detected through registers. This isn't exhaustive and may provide false
+ * negatives.
+ */
+static bool fun_adminq_stopped(struct fun_dev *fdev)
+{
+	u32 csts = readl(fdev->bar + NVME_REG_CSTS);
+
+	return (csts & (NVME_CSTS_CFS | NVME_CSTS_RDY)) != NVME_CSTS_RDY;
+}
+
+static int fun_wait_for_tag(struct fun_dev *fdev, int *cpup)
+{
+	struct sbitmap_queue *sbq = &fdev->admin_sbq;
+	struct sbq_wait_state *ws = &sbq->ws[0];
+	DEFINE_SBQ_WAIT(wait);
+	int tag;
+
+	for (;;) {
+		sbitmap_prepare_to_wait(sbq, ws, &wait, TASK_UNINTERRUPTIBLE);
+		if (fdev->suppress_cmds) {
+			tag = -ESHUTDOWN;
+			break;
+		}
+		tag = sbitmap_queue_get(sbq, cpup);
+		if (tag >= 0)
+			break;
+		schedule();
+	}
+
+	sbitmap_finish_wait(sbq, ws, &wait);
+	return tag;
+}
+
+/* Submit an asynchronous admin command. Caller is responsible for implementing
+ * any waiting or timeout. Upon command completion the callback @cb is called.
+ */
+int fun_submit_admin_cmd(struct fun_dev *fdev, struct fun_admin_req_common *cmd,
+			 fun_admin_callback_t cb, void *cb_data, bool wait_ok)
+{
+	struct fun_queue *funq = fdev->admin_q;
+	unsigned int cmdsize = cmd->len8 * 8;
+	struct fun_cmd_ctx *cmd_ctx;
+	int tag, cpu, rc = 0;
+
+	if (WARN_ON(cmdsize > (1 << funq->sqe_size_log2)))
+		return -EMSGSIZE;
+
+	tag = sbitmap_queue_get(&fdev->admin_sbq, &cpu);
+	if (tag < 0) {
+		if (!wait_ok)
+			return -EAGAIN;
+		tag = fun_wait_for_tag(fdev, &cpu);
+		if (tag < 0)
+			return tag;
+	}
+
+	cmd->cid = cpu_to_be16(tag);
+
+	cmd_ctx = &fdev->cmd_ctx[tag];
+	cmd_ctx->cb = cb;
+	cmd_ctx->cb_data = cb_data;
+
+	spin_lock(&funq->sq_lock);
+
+	if (unlikely(fdev->suppress_cmds)) {
+		rc = -ESHUTDOWN;
+		sbitmap_queue_clear(&fdev->admin_sbq, tag, cpu);
+	} else {
+		cmd_ctx->cpu = cpu;
+		memcpy(fun_sqe_at(funq, funq->sq_tail), cmd, cmdsize);
+
+		dev_dbg(fdev->dev, "admin cmd @ %u: %8ph\n", funq->sq_tail,
+			cmd);
+
+		if (++funq->sq_tail == funq->sq_depth)
+			funq->sq_tail = 0;
+		writel(funq->sq_tail, funq->sq_db);
+	}
+	spin_unlock(&funq->sq_lock);
+	return rc;
+}
+
+/* Abandon a pending admin command by clearing the issuer's callback data.
+ * Failure indicates that the command either has already completed or its
+ * completion is racing with this call.
+ */
+static bool fun_abandon_admin_cmd(struct fun_dev *fd,
+				  const struct fun_admin_req_common *cmd,
+				  void *cb_data)
+{
+	u16 cid = be16_to_cpu(cmd->cid);
+	struct fun_cmd_ctx *cmd_ctx = &fd->cmd_ctx[cid];
+
+	return cmpxchg(&cmd_ctx->cb_data, cb_data, NULL) == cb_data;
+}
+
+/* Stop submission of new admin commands and wake up any processes waiting for
+ * tags. Already submitted commands are left to complete or time out.
+ */
+static void fun_admin_stop(struct fun_dev *fdev)
+{
+	spin_lock(&fdev->admin_q->sq_lock);
+	fdev->suppress_cmds = true;
+	spin_unlock(&fdev->admin_q->sq_lock);
+	sbitmap_queue_wake_all(&fdev->admin_sbq);
+}
+
+/* The callback for synchronous execution of admin commands. It copies the
+ * command response to the caller's buffer and signals completion.
+ */
+static void fun_admin_cmd_sync_cb(struct fun_dev *fd, void *rsp, void *cb_data)
+{
+	const struct fun_admin_rsp_common *rsp_common = rsp;
+	struct fun_sync_cmd_ctx *ctx = cb_data;
+
+	if (!ctx)
+		return;         /* command issuer timed out and left */
+	if (ctx->rsp_buf) {
+		unsigned int rsp_len = rsp_common->len8 * 8;
+
+		if (unlikely(rsp_len > ctx->rsp_len)) {
+			dev_err(fd->dev,
+				"response for op %u is %uB > response buffer %uB\n",
+				rsp_common->op, rsp_len, ctx->rsp_len);
+			rsp_len = ctx->rsp_len;
+		}
+		memcpy(ctx->rsp_buf, rsp, rsp_len);
+	}
+	ctx->rsp_status = rsp_common->ret;
+	complete(&ctx->compl);
+}
+
+/* Submit a synchronous admin command. */
+int fun_submit_admin_sync_cmd(struct fun_dev *fdev,
+			      struct fun_admin_req_common *cmd, void *rsp,
+			      size_t rspsize, unsigned int timeout)
+{
+	struct fun_sync_cmd_ctx ctx = {
+		.compl = COMPLETION_INITIALIZER_ONSTACK(ctx.compl),
+		.rsp_buf = rsp,
+		.rsp_len = rspsize,
+	};
+	unsigned int cmdlen = cmd->len8 * 8;
+	unsigned long jiffies_left;
+	int ret;
+
+	ret = fun_submit_admin_cmd(fdev, cmd, fun_admin_cmd_sync_cb, &ctx,
+				   true);
+	if (ret)
+		return ret;
+
+	if (!timeout)
+		timeout = FUN_ADMIN_CMD_TO_MS;
+
+	jiffies_left = wait_for_completion_timeout(&ctx.compl,
+						   msecs_to_jiffies(timeout));
+	if (!jiffies_left) {
+		/* The command timed out. Attempt to cancel it so we can return.
+		 * But if the command is in the process of completing we'll
+		 * wait for it.
+		 */
+		if (fun_abandon_admin_cmd(fdev, cmd, &ctx)) {
+			dev_err(fdev->dev, "admin command timed out: %*ph\n",
+				cmdlen, cmd);
+			fun_admin_stop(fdev);
+			/* see if the timeout was due to a queue failure */
+			if (fun_adminq_stopped(fdev))
+				dev_err(fdev->dev,
+					"device does not accept admin commands\n");
+
+			return -ETIMEDOUT;
+		}
+		wait_for_completion(&ctx.compl);
+	}
+
+	if (ctx.rsp_status) {
+		dev_err(fdev->dev, "admin command failed, err %d: %*ph\n",
+			ctx.rsp_status, cmdlen, cmd);
+	}
+
+	return -ctx.rsp_status;
+}
+EXPORT_SYMBOL_GPL(fun_submit_admin_sync_cmd);
+
+/* Return the number of device resources of the requested type. */
+int fun_get_res_count(struct fun_dev *fdev, enum fun_admin_op res)
+{
+	union {
+		struct fun_admin_res_count_req req;
+		struct fun_admin_res_count_rsp rsp;
+	} cmd;
+	int rc;
+
+	cmd.req.common = FUN_ADMIN_REQ_COMMON_INIT2(res, sizeof(cmd.req));
+	cmd.req.count = FUN_ADMIN_SIMPLE_SUBOP_INIT(FUN_ADMIN_SUBOP_RES_COUNT,
+						    0, 0);
+
+	rc = fun_submit_admin_sync_cmd(fdev, &cmd.req.common, &cmd.rsp,
+				       sizeof(cmd), 0);
+	return rc ? rc : be32_to_cpu(cmd.rsp.count.data);
+}
+EXPORT_SYMBOL_GPL(fun_get_res_count);
+
+/* Request that the instance of resource @res with the given id be deleted. */
+int fun_res_destroy(struct fun_dev *fdev, enum fun_admin_op res,
+		    unsigned int flags, u32 id)
+{
+	struct fun_admin_generic_destroy_req req = {
+		.common = FUN_ADMIN_REQ_COMMON_INIT2(res, sizeof(req)),
+		.destroy = FUN_ADMIN_SIMPLE_SUBOP_INIT(FUN_ADMIN_SUBOP_DESTROY,
+						       flags, id)
+	};
+
+	return fun_submit_admin_sync_cmd(fdev, &req.common, NULL, 0, 0);
+}
+EXPORT_SYMBOL_GPL(fun_res_destroy);
+
+/* Bind two entities of the given types and IDs. */
+int fun_bind(struct fun_dev *fdev, enum fun_admin_bind_type type0,
+	     unsigned int id0, enum fun_admin_bind_type type1,
+	     unsigned int id1)
+{
+	struct {
+		struct fun_admin_bind_req req;
+		struct fun_admin_bind_entry entry[2];
+	} cmd = {
+		.req.common = FUN_ADMIN_REQ_COMMON_INIT2(FUN_ADMIN_OP_BIND,
+							 sizeof(cmd)),
+		.entry[0] = FUN_ADMIN_BIND_ENTRY_INIT(type0, id0),
+		.entry[1] = FUN_ADMIN_BIND_ENTRY_INIT(type1, id1),
+	};
+
+	return fun_submit_admin_sync_cmd(fdev, &cmd.req.common, NULL, 0, 0);
+}
+EXPORT_SYMBOL_GPL(fun_bind);
+
+static int fun_get_dev_limits(struct fun_dev *fdev)
+{
+	struct pci_dev *pdev = to_pci_dev(fdev->dev);
+	unsigned int cq_count, sq_count, num_dbs;
+	int rc;
+
+	rc = fun_get_res_count(fdev, FUN_ADMIN_OP_EPCQ);
+	if (rc < 0)
+		return rc;
+	cq_count = rc;
+
+	rc = fun_get_res_count(fdev, FUN_ADMIN_OP_EPSQ);
+	if (rc < 0)
+		return rc;
+	sq_count = rc;
+
+	/* The admin queue consumes 1 CQ and at least 1 SQ. To be usable the
+	 * device must provide additional queues.
+	 */
+	if (cq_count < 2 || sq_count < 2 + !!fdev->admin_q->rq_depth)
+		return -EINVAL;
+
+	/* Calculate the max QID based on SQ/CQ/doorbell counts.
+	 * SQ/CQ doorbells alternate.
+	 */
+	num_dbs = (pci_resource_len(pdev, 0) - NVME_REG_DBS) >>
+		  (2 + NVME_CAP_STRIDE(fdev->cap_reg));
+	fdev->max_qid = min3(cq_count, sq_count, num_dbs / 2) - 1;
+	fdev->kern_end_qid = fdev->max_qid + 1;
+	return 0;
+}
+
+/* Allocate all MSI-X vectors available on a function and at least @min_vecs. */
+static int fun_alloc_irqs(struct pci_dev *pdev, unsigned int min_vecs)
+{
+	int vecs, num_msix = pci_msix_vec_count(pdev);
+
+	if (num_msix < 0)
+		return num_msix;
+	if (min_vecs > num_msix)
+		return -ERANGE;
+
+	vecs = pci_alloc_irq_vectors(pdev, min_vecs, num_msix, PCI_IRQ_MSIX);
+	if (vecs > 0) {
+		dev_info(&pdev->dev,
+			 "Allocated %d IRQ vectors of %d requested\n",
+			 vecs, num_msix);
+	} else {
+		dev_err(&pdev->dev,
+			"Unable to allocate at least %u IRQ vectors\n",
+			min_vecs);
+	}
+	return vecs;
+}
+
+/* Allocate and initialize the IRQ manager state. */
+static int fun_alloc_irq_mgr(struct fun_dev *fdev)
+{
+	fdev->irq_map = bitmap_zalloc(fdev->num_irqs, GFP_KERNEL);
+	if (!fdev->irq_map)
+		return -ENOMEM;
+
+	spin_lock_init(&fdev->irqmgr_lock);
+	/* mark IRQ 0 allocated, it is used by the admin queue */
+	__set_bit(0, fdev->irq_map);
+	fdev->irqs_avail = fdev->num_irqs - 1;
+	return 0;
+}
+
+/* Reserve @nirqs of the currently available IRQs and return their indices. */
+int fun_reserve_irqs(struct fun_dev *fdev, unsigned int nirqs, u16 *irq_indices)
+{
+	unsigned int b, n = 0;
+	int err = -ENOSPC;
+
+	if (!nirqs)
+		return 0;
+
+	spin_lock(&fdev->irqmgr_lock);
+	if (nirqs > fdev->irqs_avail)
+		goto unlock;
+
+	for_each_clear_bit(b, fdev->irq_map, fdev->num_irqs) {
+		__set_bit(b, fdev->irq_map);
+		irq_indices[n++] = b;
+		if (n >= nirqs)
+			break;
+	}
+
+	WARN_ON(n < nirqs);
+	fdev->irqs_avail -= n;
+	err = n;
+unlock:
+	spin_unlock(&fdev->irqmgr_lock);
+	return err;
+}
+EXPORT_SYMBOL(fun_reserve_irqs);
+
+/* Release @nirqs previously allocated IRQS with the supplied indices. */
+void fun_release_irqs(struct fun_dev *fdev, unsigned int nirqs,
+		      u16 *irq_indices)
+{
+	unsigned int i;
+
+	spin_lock(&fdev->irqmgr_lock);
+	for (i = 0; i < nirqs; i++)
+		__clear_bit(irq_indices[i], fdev->irq_map);
+	fdev->irqs_avail += nirqs;
+	spin_unlock(&fdev->irqmgr_lock);
+}
+EXPORT_SYMBOL(fun_release_irqs);
+
+static void fun_serv_handler(struct work_struct *work)
+{
+	struct fun_dev *fd = container_of(work, struct fun_dev, service_task);
+
+	if (test_bit(FUN_SERV_DISABLED, &fd->service_flags))
+		return;
+	if (fd->serv_cb)
+		fd->serv_cb(fd);
+}
+
+void fun_serv_stop(struct fun_dev *fd)
+{
+	set_bit(FUN_SERV_DISABLED, &fd->service_flags);
+	cancel_work_sync(&fd->service_task);
+}
+EXPORT_SYMBOL_GPL(fun_serv_stop);
+
+void fun_serv_restart(struct fun_dev *fd)
+{
+	clear_bit(FUN_SERV_DISABLED, &fd->service_flags);
+	if (fd->service_flags)
+		schedule_work(&fd->service_task);
+}
+EXPORT_SYMBOL_GPL(fun_serv_restart);
+
+void fun_serv_sched(struct fun_dev *fd)
+{
+	if (!test_bit(FUN_SERV_DISABLED, &fd->service_flags))
+		schedule_work(&fd->service_task);
+}
+EXPORT_SYMBOL_GPL(fun_serv_sched);
+
+/* Check and try to get the device into a proper state for initialization,
+ * i.e., CSTS.RDY = CC.EN = 0.
+ */
+static int sanitize_dev(struct fun_dev *fdev)
+{
+	int rc;
+
+	fdev->cap_reg = readq(fdev->bar + NVME_REG_CAP);
+	fdev->cc_reg = readl(fdev->bar + NVME_REG_CC);
+
+	/* First get RDY to agree with the current EN. Give RDY the opportunity
+	 * to complete a potential recent EN change.
+	 */
+	rc = fun_wait_ready(fdev, fdev->cc_reg & NVME_CC_ENABLE);
+	if (rc)
+		return rc;
+
+	/* Next, reset the device if EN is currently 1. */
+	if (fdev->cc_reg & NVME_CC_ENABLE)
+		rc = fun_disable_ctrl(fdev);
+
+	return rc;
+}
+
+/* Undo the device initialization of fun_dev_enable(). */
+void fun_dev_disable(struct fun_dev *fdev)
+{
+	struct pci_dev *pdev = to_pci_dev(fdev->dev);
+
+	pci_set_drvdata(pdev, NULL);
+
+	if (fdev->fw_handle != FUN_HCI_ID_INVALID) {
+		fun_res_destroy(fdev, FUN_ADMIN_OP_SWUPGRADE, 0,
+				fdev->fw_handle);
+		fdev->fw_handle = FUN_HCI_ID_INVALID;
+	}
+
+	fun_disable_admin_queue(fdev);
+
+	bitmap_free(fdev->irq_map);
+	pci_free_irq_vectors(pdev);
+
+	pci_clear_master(pdev);
+	pci_disable_pcie_error_reporting(pdev);
+	pci_disable_device(pdev);
+
+	fun_unmap_bars(fdev);
+}
+EXPORT_SYMBOL(fun_dev_disable);
+
+/* Perform basic initialization of a device, including
+ * - PCI config space setup and BAR0 mapping
+ * - interrupt management initialization
+ * - 1 admin queue setup
+ * - determination of some device limits, such as number of queues.
+ */
+int fun_dev_enable(struct fun_dev *fdev, struct pci_dev *pdev,
+		   const struct fun_dev_params *areq, const char *name)
+{
+	int rc;
+
+	fdev->dev = &pdev->dev;
+	rc = fun_map_bars(fdev, name);
+	if (rc)
+		return rc;
+
+	rc = fun_set_dma_masks(fdev->dev);
+	if (rc)
+		goto unmap;
+
+	rc = pci_enable_device_mem(pdev);
+	if (rc) {
+		dev_err(&pdev->dev, "Couldn't enable device, err %d\n", rc);
+		goto unmap;
+	}
+
+	pci_enable_pcie_error_reporting(pdev);
+
+	rc = sanitize_dev(fdev);
+	if (rc)
+		goto disable_dev;
+
+	fdev->fw_handle = FUN_HCI_ID_INVALID;
+	fdev->q_depth = NVME_CAP_MQES(fdev->cap_reg) + 1;
+	fdev->db_stride = 1 << NVME_CAP_STRIDE(fdev->cap_reg);
+	fdev->dbs = fdev->bar + NVME_REG_DBS;
+
+	INIT_WORK(&fdev->service_task, fun_serv_handler);
+	fdev->service_flags = FUN_SERV_DISABLED;
+	fdev->serv_cb = areq->serv_cb;
+
+	rc = fun_alloc_irqs(pdev, areq->min_msix + 1); /* +1 for admin CQ */
+	if (rc < 0)
+		goto disable_dev;
+	fdev->num_irqs = rc;
+
+	rc = fun_alloc_irq_mgr(fdev);
+	if (rc)
+		goto free_irqs;
+
+	pci_set_master(pdev);
+	rc = fun_enable_admin_queue(fdev, areq);
+	if (rc)
+		goto free_irq_mgr;
+
+	rc = fun_get_dev_limits(fdev);
+	if (rc < 0)
+		goto disable_admin;
+
+	pci_save_state(pdev);
+	pci_set_drvdata(pdev, fdev);
+	pcie_print_link_status(pdev);
+	dev_dbg(fdev->dev, "q_depth %u, db_stride %u, max qid %d kern_end_qid %d\n",
+		fdev->q_depth, fdev->db_stride, fdev->max_qid,
+		fdev->kern_end_qid);
+	return 0;
+
+disable_admin:
+	fun_disable_admin_queue(fdev);
+free_irq_mgr:
+	pci_clear_master(pdev);
+	bitmap_free(fdev->irq_map);
+free_irqs:
+	pci_free_irq_vectors(pdev);
+disable_dev:
+	pci_disable_pcie_error_reporting(pdev);
+	pci_disable_device(pdev);
+unmap:
+	fun_unmap_bars(fdev);
+	return rc;
+}
+EXPORT_SYMBOL(fun_dev_enable);
+
+MODULE_AUTHOR("Dimitris Michailidis <dmichail@fungible.com>");
+MODULE_DESCRIPTION("Core services driver for Fungible devices");
+MODULE_LICENSE("Dual BSD/GPL");