firmware: arm_ffa: Skip creation of the notification bitmaps

When the FF-A driver is running inside a guest VM under an hypervisor,
the driver/guest VM doesn't have the permission/capability to request
the creation of notification bitmaps. For a VM, the hypervisor reserves
memory for its VM and hypervisor framework notification bitmaps and the
SPMC reserves memory for its SP and SPMC framework notification bitmaps
before the hypervisor initializes it.

The hypervisor does not initialize a VM if memory cannot be reserved
for all its notification bitmaps. So the creation of all the necessary
bitmaps are already done when the driver initialises and hence it can be
skipped. We rely on FFA_FEATURES(FFA_NOTIFICATION_BITMAP_CREATE) to fail
when running in the guest to handle this in the driver.

Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>
Link: https://lore.kernel.org/r/20240411-ffa_npi_support-v2-1-927a670254e6@arm.com
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

diff --git a/drivers/firmware/arm_ffa/driver.c b/drivers/firmware/arm_ffa/driver.c
index f2556a8e940156bc4f9d34ae5dc92aac837b688a..a2818b69c8aa5c70cf00c033c54f9347586be54e 100644 (file)
--- a/drivers/firmware/arm_ffa/driver.c
+++ b/drivers/firmware/arm_ffa/driver.c
@@ -1442,17 +1442,15 @@ static void ffa_notifications_setup(void)
        int ret, irq;
 
        ret = ffa_features(FFA_NOTIFICATION_BITMAP_CREATE, 0, NULL, NULL);
-       if (ret) {
-               pr_info("Notifications not supported, continuing with it ..\n");
-               return;
-       }
+       if (!ret) {
+               ret = ffa_notification_bitmap_create();
+               if (ret) {
+                       pr_err("Notification bitmap create error %d\n", ret);
+                       return;
+               }
 
-       ret = ffa_notification_bitmap_create();
-       if (ret) {
-               pr_info("Notification bitmap create error %d\n", ret);
-               return;
+               drv_info->bitmap_created = true;
        }
-       drv_info->bitmap_created = true;
 
        irq = ffa_sched_recv_irq_map();
        if (irq <= 0) {