Thread (64 messages) 64 messages, 4 authors, 2020-05-21

Re: [PATCH v3 03/14] remoteproc: Add new operation and flags for synchronistation

From: Bjorn Andersson <hidden>
Date: 2020-05-06 00:22:10
Also in: linux-remoteproc, lkml

On Fri 24 Apr 13:01 PDT 2020, Mathieu Poirier wrote:
Add a new sync_ops to support use cases where the remoteproc
core is synchronising with the remote processor.  Exactly when to use
the synchronisation operations is directed by the flags in structure
rproc_sync_flags.
I'm sorry, but no matter how many times I read these patches I have to
translate "synchronising" to "remote controlled", and given the number
of comments clarifying this makes me feel that we could perhaps come up
with a better name?
quoted hunk ↗ jump to hunk
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
---
 include/linux/remoteproc.h | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)
diff --git a/include/linux/remoteproc.h b/include/linux/remoteproc.h
index ac4082f12e8b..ceb3b2bba824 100644
--- a/include/linux/remoteproc.h
+++ b/include/linux/remoteproc.h
@@ -353,6 +353,23 @@ enum rsc_handling_status {
 	RSC_IGNORED	= 1,
 };
 
+/**
+ * struct rproc_sync_flags - platform specific flags indicating which
+ *			      rproc_ops to use at specific times during
+ *			      the rproc lifecycle.
+ * @on_init: true if synchronising with the remote processor at
+ *	     initialisation time
+ * @after_stop: true if synchronising with the remote processor after it was
+ *		stopped from the cmmand line
+ * @after_crash: true if synchronising with the remote processor after
+ *		 it has crashed
+ */
+struct rproc_sync_flags {
+	bool on_init;
This indirectly splits the RPROC_OFFLINE state in an "offline" and
"already-booted" state. Wouldn't it be clearer to represent this with a
new RPROC_ALREADY_BOOTED state?
+	bool after_stop;
What does it mean when this is true? That Linux can shut the remote core
down, but someone else will start it?
+	bool after_crash;
Similarly what is the expected steps to be taken by the core when this
is true? Should rproc_report_crash() simply stop/start the subdevices
and upon one of the ops somehow tell the remote controller that it can
proceed with the recovery?
quoted hunk ↗ jump to hunk
+};
+
 /**
  * struct rproc_ops - platform-specific device handlers
  * @start:	power on the device and boot it
@@ -459,6 +476,9 @@ struct rproc_dump_segment {
  * @firmware: name of firmware file to be loaded
  * @priv: private data which belongs to the platform-specific rproc module
  * @ops: platform-specific start/stop rproc handlers
+ * @sync_ops: platform-specific start/stop rproc handlers when
+ *	      synchronising with a remote processor.
+ * @sync_flags: Determine the rproc_ops to choose in specific states.
  * @dev: virtual device for refcounting and common remoteproc behavior
  * @power: refcount of users who need this rproc powered up
  * @state: state of the device
@@ -482,6 +502,7 @@ struct rproc_dump_segment {
  * @table_sz: size of @cached_table
  * @has_iommu: flag to indicate if remote processor is behind an MMU
  * @auto_boot: flag to indicate if remote processor should be auto-started
+ * @sync_with_rproc: true if currently synchronising with the rproc
  * @dump_segments: list of segments in the firmware
  * @nb_vdev: number of vdev currently handled by rproc
  */
@@ -492,6 +513,8 @@ struct rproc {
 	const char *firmware;
 	void *priv;
 	struct rproc_ops *ops;
+	struct rproc_ops *sync_ops;
Do we really need two rproc_ops, given that both are coming from the
platform driver and the sync_flags will define which one to look at?

Can't the platform driver just provide an ops table that works with the
flags it passes?

Regards,
Bjorn
quoted hunk ↗ jump to hunk
+	struct rproc_sync_flags sync_flags;
 	struct device dev;
 	atomic_t power;
 	unsigned int state;
@@ -515,6 +538,7 @@ struct rproc {
 	size_t table_sz;
 	bool has_iommu;
 	bool auto_boot;
+	bool sync_with_rproc;
 	struct list_head dump_segments;
 	int nb_vdev;
 	u8 elf_class;
-- 
2.20.1
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