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authorMathieu Poirier <mathieu.poirier@linaro.org>2021-03-12 09:24:47 -0700
committerBjorn Andersson <bjorn.andersson@linaro.org>2021-03-18 08:00:51 -0500
commit9dc9507f1880fb6225e3e058cb5219b152cbf198 (patch)
tree08840dfef1ebf94c4875befd0c35f5d6f554adde
parentd3962a397885518a85d2dc6b0c51e6594f71c30f (diff)
remoteproc: Properly deal with the resource table when detaching
If it is possible to detach the remote processor, keep an untouched copy of the resource table. That way we can start from the same resource table without having to worry about original values or what elements the startup code has changed when re-attaching to the remote processor. Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org> Reviewed-by: Arnaud Pouliquen <arnaud.pouliquen@st.com> Link: https://lore.kernel.org/r/20210312162453.1234145-12-mathieu.poirier@linaro.org Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
-rw-r--r--drivers/remoteproc/remoteproc_core.c81
-rw-r--r--include/linux/remoteproc.h3
2 files changed, 84 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);
diff --git a/include/linux/remoteproc.h b/include/linux/remoteproc.h
index fc2cca600423..8b795b544f75 100644
--- a/include/linux/remoteproc.h
+++ b/include/linux/remoteproc.h
@@ -516,6 +516,8 @@ struct rproc_dump_segment {
* @recovery_disabled: flag that state if recovery was disabled
* @max_notifyid: largest allocated notify id.
* @table_ptr: pointer to the resource table in effect
+ * @clean_table: copy of the resource table without modifications. Used
+ * when a remote processor is attached or detached from the core
* @cached_table: copy of the resource table
* @table_sz: size of @cached_table
* @has_iommu: flag to indicate if remote processor is behind an MMU
@@ -552,6 +554,7 @@ struct rproc {
bool recovery_disabled;
int max_notifyid;
struct resource_table *table_ptr;
+ struct resource_table *clean_table;
struct resource_table *cached_table;
size_t table_sz;
bool has_iommu;