remtoteproc: maintain max notifyid

Some of the rproc drivers (STE modem specifically) needs to know
the range of the notification IDs used for notifying the device.

Maintain a variable in struct rproc holding the largest allocated
notification id, so low-level rproc drivers could access it.
Signed-off-by: Sjur Brændeland <sjur.brandeland@stericsson.com>
[ohad: rebase, slightly edit commit log]
Signed-off-by: Ohad Ben-Cohen <ohad@wizery.com>

drivers/remoteproc/remoteproc_core.c

@@ -228,6 +228,9 @@ int rproc_alloc_vring(struct rproc_vdev *rvdev, int i)
 		return ret;
 	}
 
+	/* Store largest notifyid */
+	rproc->max_notifyid = max(rproc->max_notifyid, notifyid);
+
 	dev_dbg(dev, "vring%d: va %p dma %x size %x idr %d\n", i, va,
 					dma, size, notifyid);
 
@@ -269,13 +272,25 @@ rproc_parse_vring(struct rproc_vdev *rvdev, struct fw_rsc_vdev *rsc, int i)
 	return 0;
 }
 
+static int rproc_max_notifyid(int id, void *p, void *data)
+{
+	int *maxid = data;
+	*maxid = max(*maxid, id);
+	return 0;
+}
+
 void rproc_free_vring(struct rproc_vring *rvring)
 {
 	int size = PAGE_ALIGN(vring_size(rvring->len, rvring->align));
 	struct rproc *rproc = rvring->rvdev->rproc;
+	int maxid = 0;
 
 	dma_free_coherent(rproc->dev.parent, size, rvring->va, rvring->dma);
 	idr_remove(&rproc->notifyids, rvring->notifyid);
+
+	/* Find the largest remaining notifyid */
+	idr_for_each(&rproc->notifyids, rproc_max_notifyid, &maxid);
+	rproc->max_notifyid = maxid;
 }
 
 /**

include/linux/remoteproc.h

@@ -400,6 +400,7 @@ enum rproc_crash_type {
  * @crash_cnt: crash counter
  * @crash_comp: completion used to sync crash handler and the rproc reload
  * @recovery_disabled: flag that state if recovery was disabled
+ * @max_notifyid: largest allocated notify id.
  */
 struct rproc {
 	struct klist_node node;
@@ -427,6 +428,7 @@ struct rproc {
 	unsigned crash_cnt;
 	struct completion crash_comp;
 	bool recovery_disabled;
+	int max_notifyid;
 };
 
 /* we currently support only two vrings per rvdev */