Re: [PATCH v3 02/14] remoteproc: Introduce function rproc_alloc_internals()

On Tue, May 05, 2020 at 03:31:58PM -0700, Bjorn Andersson wrote:

On Fri 24 Apr 13:01 PDT 2020, Mathieu Poirier wrote:

quoted

In scenarios where the remote processor's lifecycle is entirely
managed by another entity there is no point in allocating memory for
a firmware name since it will never be used.  The same goes for a core
set of operations.

As such introduce function rproc_alloc_internals() to decide if the
allocation of a firmware name and the core operations need to be done.
That way rproc_alloc() can be kept as clean as possible.

Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
---
 drivers/remoteproc/remoteproc_core.c | 31 +++++++++++++++++++++++-----
 1 file changed, 26 insertions(+), 5 deletions(-)

diff --git a/drivers/remoteproc/remoteproc_core.c b/drivers/remoteproc/remoteproc_core.c
index 448262470fc7..1b4756909584 100644
--- a/drivers/remoteproc/remoteproc_core.c
+++ b/drivers/remoteproc/remoteproc_core.c

@@ -2076,6 +2076,30 @@ static int rproc_alloc_ops(struct rproc *rproc, const struct rproc_ops *ops)
 	return 0;
 }
 
+static int rproc_alloc_internals(struct rproc *rproc,
+				 const struct rproc_ops *ops,
+				 const char *name, const char *firmware)
+{
+	int ret;
+
+	/*
+	 * In scenarios where the remote processor's lifecycle is entirely
+	 * managed by another entity there is no point in carrying a set
+	 * of operations that will never be used.
+	 *
+	 * And since no firmware will ever be loaded, there is no point in
+	 * allocating memory for it either.

While this is true, I would expect that there are cases where the
remoteproc has ops but no firmware.

That is a scenario I did not envisioned, but I agree, the remote processor could
be fetching from a private ROM memory and still required handling from the
remoteproc core.

How about splitting this decision already now; i.e. moving the if(!ops)
to rproc_alloc_ops() and perhaps only allocate firmware if ops->load is
specified?

Or just add "if (ops->load)" before calling rproc_alloc_firmware()...  Otherwise
we need to change the calling order of rproc_alloc_firmware() and
rproc_alloc_ops() in order to make sure 'ops' is valid when calling the former.
Either way I'll add a comment with the rationale you have detailed above.

Regards,
Bjorn

quoted

+	 */
+	if (!ops)
+		return 0;
+
+	ret = rproc_alloc_firmware(rproc, name, firmware);
+	if (ret)
+		return ret;
+
+	return rproc_alloc_ops(rproc, ops);
+}
+
 /**
  * rproc_alloc() - allocate a remote processor handle
  * @dev: the underlying device

@@ -2105,7 +2129,7 @@ struct rproc *rproc_alloc(struct device *dev, const char *name,
 {
 	struct rproc *rproc;
 
-	if (!dev || !name || !ops)
+	if (!dev || !name)
 		return NULL;
 
 	rproc = kzalloc(sizeof(struct rproc) + len, GFP_KERNEL);

@@ -2128,10 +2152,7 @@ struct rproc *rproc_alloc(struct device *dev, const char *name,
 	if (!rproc->name)
 		goto put_device;
 
-	if (rproc_alloc_firmware(rproc, name, firmware))
-		goto put_device;
-
-	if (rproc_alloc_ops(rproc, ops))
+	if (rproc_alloc_internals(rproc, ops, name, firmware))
 		goto put_device;
 
 	/* Assign a unique device index and name */

-- 
2.20.1