linux-kernel - [PATCH RFT v2 12/18] firmware: arm_ffa: Add notification handling mechanism

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Date:   Tue, 19 Sep 2023 18:41:00 +0100
From:   Sudeep Holla <sudeep.holla@....com>
To:     linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        Sudeep Holla <sudeep.holla@....com>,
        Jens Wiklander <jens.wiklander@...aro.org>,
        Marc Bonnici <marc.bonnici@....com>,
        Coboy Chen <coboy.chen@...iatek.com>,
        Lorenzo Pieralisi <lpieralisi@...nel.org>,
        Olivier Deprez <olivier.deprez@....com>
Subject: [PATCH RFT v2 12/18] firmware: arm_ffa: Add notification handling
 mechanism

With all the necessary plumbing in place, let us add handling the
notifications as part of schedule receiver interrupt handler. In order
to do so, we need to just register scheduling callback on behalf of the
driver partition.

Signed-off-by: Sudeep Holla <sudeep.holla@....com>
---
 drivers/firmware/arm_ffa/driver.c | 62 ++++++++++++++++++++++++++++++++++++++-
 1 file changed, 61 insertions(+), 1 deletion(-)

diff --git a/drivers/firmware/arm_ffa/driver.c b/drivers/firmware/arm_ffa/driver.c
index b95c7979da8d..8a5b5c274bb9 100644
--- a/drivers/firmware/arm_ffa/driver.c
+++ b/drivers/firmware/arm_ffa/driver.c
@@ -103,6 +103,7 @@ struct ffa_drv_info {
 	unsigned int cpuhp_state;
 	struct ffa_pcpu_irq __percpu *irq_pcpu;
 	struct workqueue_struct *notif_pcpu_wq;
+	struct work_struct notif_pcpu_work;
 	struct work_struct irq_work;
 	bool info_get_64b;
 	struct xarray partition_info;
@@ -1045,6 +1046,55 @@ static int ffa_notify_send(struct ffa_device *dev, int notify_id,
 				    BIT(notify_id));
 }
 
+static void handle_notif_callbacks(u64 bitmap, u16 part_id)
+{
+	int notify_id;
+	struct notifier_cb_info *cb_info = NULL;
+
+	for (notify_id = 0; notify_id <= FFA_MAX_NOTIFICATIONS && bitmap;
+	     notify_id++, bitmap >>= 1) {
+		if (!(bitmap & 1))
+			continue;
+
+		mutex_lock(&drv_info->notify_lock);
+		cb_info = notifier_hash_node_get(part_id, notify_id);
+		mutex_unlock(&drv_info->notify_lock);
+
+		if (cb_info && cb_info->cb)
+			cb_info->cb(notify_id, cb_info->cb_data);
+	}
+}
+
+static void notif_pcpu_irq_work_fn(struct work_struct *work)
+{
+	int rc;
+	struct ffa_notify_bitmaps bitmaps;
+	struct ffa_drv_info *info = container_of(work, struct ffa_drv_info,
+						 notif_pcpu_work);
+
+	rc = ffa_notification_get(ALL_NOTIFICATION_BITMAPS_FLAGS, &bitmaps);
+	if (rc) {
+		pr_err("Failed to retrieve notifications with %d!\n", rc);
+		return;
+	}
+
+	handle_notif_callbacks(bitmaps.vm_map, info->vm_id);
+	handle_notif_callbacks(bitmaps.sp_map, info->vm_id);
+	handle_notif_callbacks(bitmaps.arch_map, info->vm_id);
+}
+
+static void
+ffa_self_notif_handle(u16 vcpu, bool is_per_vcpu, void *cb_data)
+{
+	struct ffa_drv_info *info = cb_data;
+
+	if (!is_per_vcpu)
+		notif_pcpu_irq_work_fn(&info->notif_pcpu_work);
+	else
+		queue_work_on(vcpu, info->notif_pcpu_wq,
+			      &info->notif_pcpu_work);
+}
+
 static const struct ffa_info_ops ffa_drv_info_ops = {
 	.api_version_get = ffa_api_version_get,
 	.partition_info_get = ffa_partition_info_get,
@@ -1149,6 +1199,13 @@ static void ffa_setup_partitions(void)
 	drv_info->partition_count = count;
 
 	kfree(pbuf);
+
+	/* Allocate for the host */
+	info = kzalloc(sizeof(*info), GFP_KERNEL);
+	if (!info)
+		return;
+	xa_store(&drv_info->partition_info, drv_info->vm_id, info, GFP_KERNEL);
+	drv_info->partition_count++;
 }
 
 static void ffa_partitions_cleanup(void)
@@ -1292,6 +1349,7 @@ static int ffa_init_pcpu_irq(unsigned int irq)
 	}
 
 	INIT_WORK(&drv_info->irq_work, ffa_sched_recv_irq_work_fn);
+	INIT_WORK(&drv_info->notif_pcpu_work, notif_pcpu_irq_work_fn);
 	drv_info->notif_pcpu_wq = create_workqueue("ffa_pcpu_irq_notification");
 	if (!drv_info->notif_pcpu_wq)
 		return -EINVAL;
@@ -1349,7 +1407,9 @@ static int ffa_notifications_setup(void)
 	hash_init(drv_info->notifier_hash);
 	mutex_init(&drv_info->notify_lock);
 
-	return 0;
+	/* Register internal scheduling callback */
+	return ffa_sched_recv_cb_update(drv_info->vm_id,
+					ffa_self_notif_handle, drv_info, true);
 cleanup:
 	ffa_notifications_cleanup();
 	return ret;

-- 
2.42.0