diff --git a/Documentation/ABI/testing/sysfs-class-cxl b/Documentation/ABI/testing/sysfs-class-cxl
index 4ba0a2a..dae2b38 100644
--- a/Documentation/ABI/testing/sysfs-class-cxl
+++ b/Documentation/ABI/testing/sysfs-class-cxl
@@ -220,8 +220,11 @@ What:           /sys/class/cxl/<card>/reset
 Date:           October 2014
 Contact:        linuxppc-dev@lists.ozlabs.org
 Description:    write only
-                Writing 1 will issue a PERST to card which may cause the card
-                to reload the FPGA depending on load_image_on_perst.
+                Writing 1 will issue a PERST to card provided there are no
+		contexts active on any one of the card AFUs. This may cause
+		the card to reload the FPGA depending on load_image_on_perst.
+		Writing -1 will do a force PERST irrespective of any active
+		contexts on the card AFUs.
 Users:		https://github.com/ibm-capi/libcxl
 
 What:		/sys/class/cxl/<card>/perst_reloads_same_image (not in a guest)
diff --git a/drivers/misc/cxl/api.c b/drivers/misc/cxl/api.c
index f3d34b9..85bb2d9 100644
--- a/drivers/misc/cxl/api.c
+++ b/drivers/misc/cxl/api.c
@@ -236,10 +236,19 @@ int cxl_start_context(struct cxl_context *ctx, u64 wed,
 		ctx->real_mode = false;
 	}
 
+	/*
+	 * Increment the mapped context count for adapter. This also checks
+	 * if adapter_context_lock is taken.
+	 */
+	rc = cxl_adapter_context_get(ctx->afu->adapter);
+	if (rc)
+		goto out;
+
 	cxl_ctx_get();
 
 	if ((rc = cxl_ops->attach_process(ctx, kernel, wed, 0))) {
 		put_pid(ctx->pid);
+		cxl_adapter_context_put(ctx->afu->adapter);
 		cxl_ctx_put();
 		goto out;
 	}
diff --git a/drivers/misc/cxl/context.c b/drivers/misc/cxl/context.c
index c466ee2..5e506c1 100644
--- a/drivers/misc/cxl/context.c
+++ b/drivers/misc/cxl/context.c
@@ -238,6 +238,9 @@ int __detach_context(struct cxl_context *ctx)
 	put_pid(ctx->glpid);
 
 	cxl_ctx_put();
+
+	/* Decrease the attached context count on the adapter */
+	cxl_adapter_context_put(ctx->afu->adapter);
 	return 0;
 }
 
diff --git a/drivers/misc/cxl/cxl.h b/drivers/misc/cxl/cxl.h
index 01d372a..ed89c57 100644
--- a/drivers/misc/cxl/cxl.h
+++ b/drivers/misc/cxl/cxl.h
@@ -618,6 +618,14 @@ struct cxl {
 	bool perst_select_user;
 	bool perst_same_image;
 	bool psl_timebase_synced;
+
+	/*
+	 * number of contexts mapped on to this card.
+	 * +ve: Number of contexts mapped and new one can be mapped.
+	 *  0 : No active contexts and new ones can be mapped.
+	 * -ve: No contexts mapped and new ones cannot be mapped.
+	 */
+	atomic_t contexts_num;
 };
 
 int cxl_pci_alloc_one_irq(struct cxl *adapter);
@@ -944,4 +952,17 @@ bool cxl_pci_is_vphb_device(struct pci_dev *dev);
 
 /* decode AFU error bits in the PSL register PSL_SERR_An */
 void cxl_afu_decode_psl_serr(struct cxl_afu *afu, u64 serr);
+
+/*
+ * Increments the number of attached contexts on an adapter.
+ * Incase an adapter_context_lock is taken the return -EBUSY.
+ */
+int cxl_adapter_context_get(struct cxl *adapter);
+
+/* Decrements the number of attached contexts on an adapter */
+void cxl_adapter_context_put(struct cxl *adapter);
+
+/* If no active contexts then prevents contexts from being attached */
+int cxl_adapter_context_lock(struct cxl *adapter);
+
 #endif
diff --git a/drivers/misc/cxl/file.c b/drivers/misc/cxl/file.c
index 5fb9894..3b2272a 100644
--- a/drivers/misc/cxl/file.c
+++ b/drivers/misc/cxl/file.c
@@ -205,11 +205,20 @@ static long afu_ioctl_start_work(struct cxl_context *ctx,
 	ctx->pid = get_task_pid(current, PIDTYPE_PID);
 	ctx->glpid = get_task_pid(current->group_leader, PIDTYPE_PID);
 
+	/*
+	 * Increment the mapped context count for adapter. This also checks
+	 * if adapter_context_lock is taken.
+	 */
+	rc = cxl_adapter_context_get(ctx->afu->adapter);
+	if (rc)
+		goto out;
+
 	trace_cxl_attach(ctx, work.work_element_descriptor, work.num_interrupts, amr);
 
 	if ((rc = cxl_ops->attach_process(ctx, false, work.work_element_descriptor,
 							amr))) {
 		afu_release_irqs(ctx, ctx);
+		cxl_adapter_context_put(ctx->afu->adapter);
 		goto out;
 	}
 
diff --git a/drivers/misc/cxl/main.c b/drivers/misc/cxl/main.c
index d9be23b2..5c3c02a 100644
--- a/drivers/misc/cxl/main.c
+++ b/drivers/misc/cxl/main.c
@@ -243,8 +243,9 @@ struct cxl *cxl_alloc_adapter(void)
 	if (dev_set_name(&adapter->dev, "card%i", adapter->adapter_num))
 		goto err2;
 
-	return adapter;
+	atomic_set(&adapter->contexts_num, 0);
 
+	return adapter;
 err2:
 	cxl_remove_adapter_nr(adapter);
 err1:
@@ -286,6 +287,27 @@ int cxl_afu_select_best_mode(struct cxl_afu *afu)
 	return 0;
 }
 
+int cxl_adapter_context_get(struct cxl *adapter)
+{
+	int rc;
+
+	rc = atomic_inc_unless_negative(&adapter->contexts_num);
+	return rc >= 0 ? 0 : -EBUSY;
+}
+
+void cxl_adapter_context_put(struct cxl *adapter)
+{
+	atomic_dec_if_positive(&adapter->contexts_num);
+}
+
+int cxl_adapter_context_lock(struct cxl *adapter)
+{
+	int rc;
+	/* no active contexts -> contexts_num == 0 */
+	rc = atomic_cmpxchg(&adapter->contexts_num, 0, -1);
+	return rc ? -EBUSY : 0;
+}
+
 static int __init init_cxl(void)
 {
 	int rc = 0;
diff --git a/drivers/misc/cxl/sysfs.c b/drivers/misc/cxl/sysfs.c
index b043c20..592dbf2 100644
--- a/drivers/misc/cxl/sysfs.c
+++ b/drivers/misc/cxl/sysfs.c
@@ -75,12 +75,22 @@ static ssize_t reset_adapter_store(struct device *device,
 	int val;
 
 	rc = sscanf(buf, "%i", &val);
-	if ((rc != 1) || (val != 1))
+	if ((rc != 1) || (val != 1 && val != -1))
 		return -EINVAL;
 
-	if ((rc = cxl_ops->adapter_reset(adapter)))
-		return rc;
-	return count;
+	/*
+	 * See if we can lock the context mapping that's only allowed
+	 * when there are no contexts attached to the adapter. Once
+	 * taken this will also prevent any context being attached.
+	 */
+	if (val == 1)
+		rc = cxl_adapter_context_lock(adapter);
+
+	/* Perform a forced adapter reset */
+	if (rc >= 0)
+		rc = cxl_ops->adapter_reset(adapter);
+
+	return rc ? rc : count;
 }
 
 static ssize_t load_image_on_perst_show(struct device *device,
