qcacmn: Add new HAL API to get SRNG descriptor which is pending reap

To release/flush buffers from source SRNGs which have not been reaped yet,
add a new HAL API to get next descriptor which is pending reap

Change-Id: Ibe490d8f8667ed046beb98fe19bfd7feb31aa286
CRs-Fixed: 2165595

hal/wifi3.0/hal_api.h

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2016-2017 The Linux Foundation. All rights reserved.
+ * Copyright (c) 2016-2018 The Linux Foundation. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
@@ -579,6 +579,33 @@ static inline void *hal_srng_src_get_next_reaped(void *hal_soc, void *hal_ring)
 	return NULL;
 }
 
+/**
+ * hal_srng_src_pending_reap_next - Reap next entry from a source ring and
+ * move reap pointer. This API is used in detach path to release any buffers
+ * associated with ring entries which are pending reap.
+ *
+ * @hal_soc: Opaque HAL SOC handle
+ * @hal_ring: Source ring pointer
+ *
+ * Return: Opaque pointer for next ring entry; NULL on failire
+ */
+static inline void *hal_srng_src_pending_reap_next(void *hal_soc, void *hal_ring)
+{
+	struct hal_srng *srng = (struct hal_srng *)hal_ring;
+	uint32_t *desc;
+
+	uint32_t next_reap_hp = (srng->u.src_ring.reap_hp + srng->entry_size) %
+		srng->ring_size;
+
+	if (next_reap_hp != srng->u.src_ring.hp) {
+		desc = &(srng->ring_base_vaddr[next_reap_hp]);
+		srng->u.src_ring.reap_hp = next_reap_hp;
+		return (void *)desc;
+	}
+
+	return NULL;
+}
+
 /**
  * hal_srng_src_done_val -
  *