From f255d366fdeb974f6d0728ac598fb21fc45a67cd Mon Sep 17 00:00:00 2001
From: Taylor R Campbell <riastradh@NetBSD.org>
Date: Sun, 21 Aug 2022 00:31:21 +0000
Subject: [PATCH] WIP: nvme(4): Add sysctl hw.nvmeN.ioqM.check=1 trigger.

This triggers checking the queue as if an interrupt had arrived.
Should not usually be necessary but this may help diagnose driver or
device bugs.
---
 sys/dev/ic/nvme.c    | 43 +++++++++++++++++++++++++++++++++++++++++++
 sys/dev/ic/nvmevar.h |  3 +++
 2 files changed, 46 insertions(+)

diff --git a/sys/dev/ic/nvme.c b/sys/dev/ic/nvme.c
index a4eca421782f..7d048eecd447 100644
--- a/sys/dev/ic/nvme.c
+++ b/sys/dev/ic/nvme.c
@@ -33,6 +33,7 @@ __KERNEL_RCSID(0, "$NetBSD: nvme.c,v 1.67 2022/09/13 10:14:20 riastradh Exp $");
 #include <sys/proc.h>
 #include <sys/queue.h>
 #include <sys/mutex.h>
+#include <sys/sysctl.h>
 
 #include <uvm/uvm_extern.h>
 
@@ -401,6 +402,12 @@ nvme_attach(struct nvme_softc *sc)
 		return 1;
 	}
 
+	sysctl_createv(&sc->sc_sysctllog, 0, NULL, &sc->sc_sysctlnode,
+	    CTLFLAG_PERMANENT, CTLTYPE_NODE, device_xname(sc->sc_dev),
+	    SYSCTL_DESCR("nvme device"),
+	    NULL, 0, NULL, 0,
+	    CTL_HW, CTL_CREATE, CTL_EOL);
+
 	sc->sc_admin_q = nvme_q_alloc(sc, NVME_ADMIN_Q, adminq_entries,
 	    sc->sc_dstrd);
 	if (sc->sc_admin_q == NULL) {
@@ -1926,6 +1933,24 @@ nvme_ccbs_free(struct nvme_queue *q)
 	mutex_destroy(&q->q_ccb_mtx);
 }
 
+static int
+nvme_q_sysctl(SYSCTLFN_ARGS)
+{
+	struct sysctlnode node = *rnode;
+	struct nvme_queue *q = node.sysctl_data;
+	int arg = 0;
+	int error;
+
+	node.sysctl_data = &arg;
+	error = sysctl_lookup(SYSCTLFN_CALL(&node));
+	if (error || newp == NULL)
+		return error;
+	if (arg)
+		nvme_q_complete(q->q_sc, q);
+
+	return 0;
+}
+
 static struct nvme_queue *
 nvme_q_alloc(struct nvme_softc *sc, uint16_t id, u_int entries, u_int dstrd)
 {
@@ -1974,6 +1999,24 @@ nvme_q_alloc(struct nvme_softc *sc, uint16_t id, u_int entries, u_int dstrd)
 		goto free_cq;
 	}
 
+    {
+	char qname[128];
+	const struct sysctlnode *qnode;
+
+	if (id == NVME_ADMIN_Q)
+		snprintf(qname, sizeof qname, "adminq");
+	else
+		snprintf(qname, sizeof qname, "ioq%u", id);
+	sysctl_createv(&sc->sc_sysctllog, 0, &sc->sc_sysctlnode, &qnode,
+	    CTLFLAG_PERMANENT, CTLTYPE_NODE, qname,
+	    SYSCTL_DESCR("Queue stuff"),
+	    NULL, 0, NULL, 0, CTL_CREATE, CTL_EOL);
+	sysctl_createv(&sc->sc_sysctllog, 0, &qnode, NULL,
+	    CTLFLAG_PERMANENT, CTLTYPE_INT, "check",
+	    SYSCTL_DESCR("Check queue as if we received an interrupt"),
+	    &nvme_q_sysctl, 0, (int *)q, 0, CTL_CREATE, CTL_EOL);
+    }
+
 	return q;
 
 free_cq:
diff --git a/sys/dev/ic/nvmevar.h b/sys/dev/ic/nvmevar.h
index 0920ab644767..13ef4f4f90d5 100644
--- a/sys/dev/ic/nvmevar.h
+++ b/sys/dev/ic/nvmevar.h
@@ -169,6 +169,9 @@ struct nvme_softc {
 #define	NVME_QUIRK_NOMSI		__BIT(1)
 
 	char			sc_modelname[81];
+
+	struct sysctllog	*sc_sysctllog;
+	const struct sysctlnode	*sc_sysctlnode;
 };
 
 #define	lemtoh16(p)	le16toh(*((uint16_t *)(p)))