1 files changed, 81 insertions, 0 deletions

diff --git a/drivers/remoteproc/remoteproc_core.c b/drivers/remoteproc/remoteproc_core.c
index 78a36a3723ec..57c851d22ba6 100644
--- a/drivers/remoteproc/remoteproc_core.c
+++ b/drivers/remoteproc/remoteproc_core.c
@@ -1562,6 +1562,24 @@ static int rproc_set_rsc_table(struct rproc *rproc)
 		return ret;
 	}
 
+	/*
+	 * If it is possible to detach the remote processor, keep an untouched
+	 * copy of the resource table.  That way we can start fresh again when
+	 * the remote processor is re-attached, that is:
+	 *
+	 *      DETACHED -> ATTACHED -> DETACHED -> ATTACHED
+	 *
+	 * Free'd in rproc_reset_rsc_table_on_detach() and
+	 * rproc_reset_rsc_table_on_stop().
+	 */
+	if (rproc->ops->detach) {
+		rproc->clean_table = kmemdup(table_ptr, table_sz, GFP_KERNEL);
+		if (!rproc->clean_table)
+			return -ENOMEM;
+	} else {
+		rproc->clean_table = NULL;
+	}
+
 	rproc->cached_table = NULL;
 	rproc->table_ptr = table_ptr;
 	rproc->table_sz = table_sz;
@@ -1569,6 +1587,59 @@ static int rproc_set_rsc_table(struct rproc *rproc)
 	return 0;
 }
 
+static int rproc_reset_rsc_table_on_detach(struct rproc *rproc)
+{
+	struct resource_table *table_ptr;
+
+	/* A resource table was never retrieved, nothing to do here */
+	if (!rproc->table_ptr)
+		return 0;
+
+	/*
+	 * If we made it to this point a clean_table _must_ have been
+	 * allocated in rproc_set_rsc_table().  If one isn't present
+	 * something went really wrong and we must complain.
+	 */
+	if (WARN_ON(!rproc->clean_table))
+		return -EINVAL;
+
+	/* Remember where the external entity installed the resource table */
+	table_ptr = rproc->table_ptr;
+
+	/*
+	 * If we made it here the remote processor was started by another
+	 * entity and a cache table doesn't exist.  As such make a copy of
+	 * the resource table currently used by the remote processor and
+	 * use that for the rest of the shutdown process.  The memory
+	 * allocated here is free'd in rproc_detach().
+	 */
+	rproc->cached_table = kmemdup(rproc->table_ptr,
+				      rproc->table_sz, GFP_KERNEL);
+	if (!rproc->cached_table)
+		return -ENOMEM;
+
+	/*
+	 * Use a copy of the resource table for the remainder of the
+	 * shutdown process.
+	 */
+	rproc->table_ptr = rproc->cached_table;
+
+	/*
+	 * Reset the memory area where the firmware loaded the resource table
+	 * to its original value.  That way when we re-attach the remote
+	 * processor the resource table is clean and ready to be used again.
+	 */
+	memcpy(table_ptr, rproc->clean_table, rproc->table_sz);
+
+	/*
+	 * The clean resource table is no longer needed.  Allocated in
+	 * rproc_set_rsc_table().
+	 */
+	kfree(rproc->clean_table);
+
+	return 0;
+}
+
 /*
  * Attach to remote processor - similar to rproc_fw_boot() but without
  * the steps that deal with the firmware image.
@@ -1727,6 +1798,13 @@ static int __rproc_detach(struct rproc *rproc)
 	/* Stop any subdevices for the remote processor */
 	rproc_stop_subdevices(rproc, false);
 
+	/* the installed resource table is no longer accessible */
+	ret = rproc_reset_rsc_table_on_detach(rproc);
+	if (ret) {
+		dev_err(dev, "can't reset resource table: %d\n", ret);
+		return ret;
+	}
+
 	/* Tell the remote processor the core isn't available anymore */
 	ret = rproc->ops->detach(rproc);
 	if (ret) {
@@ -2003,6 +2081,9 @@ int rproc_detach(struct rproc *rproc)
 
 	rproc_disable_iommu(rproc);
 
+	/* Free the copy of the resource table */
+	kfree(rproc->cached_table);
+	rproc->cached_table = NULL;
 	rproc->table_ptr = NULL;
 out:
 	mutex_unlock(&rproc->lock);