Re: [PATCH v2 3/8] firmware: arm_scmi: introduce new protocol operations support
From: Thara Gopinath
Date: Fri Nov 06 2020 - 11:07:22 EST
On 11/4/20 1:08 PM, Cristian Marussi wrote:
Hi,
On Wed, Nov 04, 2020 at 11:16:31AM -0500, Thara Gopinath wrote:
Hi Cristian,
On 10/28/20 4:29 PM, Cristian Marussi wrote:
Expose a new generic get/put protocols API based on protocol handles;
provide also a devres managed version also for notifications.
minor nit.. Maybe yous should reword this! Kind of confusing to understand!
Also, if it was me, I will separate the notifications and get/put hooks
into two separate patches. Not an issue though if you want to keep it
in the same patch.
You're right I have to reword the commit message, and I'll review the
possibility of a further split, even though many parts of this series
are tightly bound together given the kind of changes so sometimes to
avoid breaking bisectability I had to push painfully long patches (like
6/8 :< )...but maybe I've got it wrong and this is not the case here.
All SCMI drivers still keep using the old handle based interface.
Signed-off-by: Cristian Marussi <cristian.marussi@xxxxxxx>
---
drivers/firmware/arm_scmi/driver.c | 126 +++++++++++++++++++++++++++++
drivers/firmware/arm_scmi/notify.c | 123 ++++++++++++++++++++++++++++
include/linux/scmi_protocol.h | 34 +++++++-
3 files changed, 282 insertions(+), 1 deletion(-)
diff --git a/drivers/firmware/arm_scmi/driver.c b/drivers/firmware/arm_scmi/driver.c
index 8ca04acb6abb..4d86aafbf465 100644
--- a/drivers/firmware/arm_scmi/driver.c
+++ b/drivers/firmware/arm_scmi/driver.c
@@ -15,6 +15,7 @@
*/
#include <linux/bitmap.h>
+#include <linux/device.h>
#include <linux/export.h>
#include <linux/idr.h>
#include <linux/io.h>
@@ -728,6 +729,38 @@ void scmi_release_protocol(struct scmi_handle *handle, u8 protocol_id)
mutex_unlock(&info->protocols_mtx);
}
+/**
+ * scmi_get_protocol_operations - Get protocol operations
+ * @handle: A reference to the SCMI platform instance.
+ * @protocol_id: The protocol being requested.
+ * @ph: A pointer reference used to pass back the associated protocol handle.
+ *
+ * Get hold of a protocol accounting for its usage, eventually triggering its
+ * initialization, and returning the protocol specific operations and related
+ * protocol handle which will be used as first argument in most of the protocols
+ * operations methods.
+ *
+ * Return: A reference to the requested protocol operations or error.
+ * Must be checked for errors by caller.
+ */
+static const void __must_check *
+scmi_get_protocol_operations(struct scmi_handle *handle, u8 protocol_id,
+ struct scmi_protocol_handle **ph)
+{
+ struct scmi_protocol_instance *pi;
+
+ if (!ph)
+ return ERR_PTR(-EINVAL);
+
+ pi = scmi_get_protocol_instance(handle, protocol_id);
+ if (IS_ERR(pi))
+ return pi;
+
+ *ph = &pi->ph;
+
+ return pi->proto->ops;
+}
+
void scmi_setup_protocol_implemented(const struct scmi_handle *handle,
u8 *prot_imp)
{
@@ -751,6 +784,95 @@ scmi_is_protocol_implemented(const struct scmi_handle *handle, u8 prot_id)
return false;
}
+struct scmi_protocol_devres {
+ struct scmi_handle *handle;
+ u8 protocol_id;
+};
+
+static void scmi_devm_release_protocol(struct device *dev, void *res)
+{
+ struct scmi_protocol_devres *dres = res;
+
+ scmi_release_protocol(dres->handle, dres->protocol_id);
+}
+
+/**
+ * scmi_devm_get_protocol_ops - Devres managed get protocol operations
+ * @sdev: A reference to an scmi_device whose embedded struct device is to
+ * be used for devres accounting.
+ * @protocol_id: The protocol being requested.
+ * @ph: A pointer reference used to pass back the associated protocol handle.
+ *
+ * Get hold of a protocol accounting for its usage, eventually triggering its
+ * initialization, and returning the protocol specific operations and related
+ * protocol handle which will be used as first argument in most of the
+ * protocols operations methods.
+ * Being a devres based managed method, protocol hold will be automatically
+ * released, and possibly de-initialized on last user, once the SCMI driver
+ * owning the scmi_device is unbound from it.
+ *
+ * Return: A reference to the requested protocol operations or error.
+ * Must be checked for errors by caller.
+ */
+static const void __must_check *
+scmi_devm_get_protocol_ops(struct scmi_device *sdev, u8 protocol_id,
+ struct scmi_protocol_handle **ph)
+{
+ struct scmi_protocol_instance *pi;
+ struct scmi_protocol_devres *dres;
+ struct scmi_handle *handle = sdev->handle;
+
+ if (!ph)
+ return ERR_PTR(-EINVAL);
+
+ dres = devres_alloc(scmi_devm_release_protocol,
+ sizeof(*dres), GFP_KERNEL);
+ if (!dres)
+ return ERR_PTR(-ENOMEM);
+
+ pi = scmi_get_protocol_instance(handle, protocol_id);
+ if (IS_ERR(pi)) {
+ devres_free(dres);
+ return pi;
+ }
+
+ dres->handle = handle;
+ dres->protocol_id = protocol_id;
+ devres_add(&sdev->dev, dres);
+
+ *ph = &pi->ph;
+
+ return pi->proto->ops;
+}
+
+static int scmi_devm_protocol_match(struct device *dev, void *res, void *data)
+{
+ struct scmi_protocol_devres *dres = res;
+
+ if (WARN_ON(!dres || !data))
+ return 0;
+
+ return dres->protocol_id == *((u8 *)data);
+}
+
+/**
+ * scmi_devm_put_protocol_ops - Devres managed put protocol operations
+ * @sdev: A reference to an scmi_device whose embedded struct device is to
+ * be used for devres accounting.
+ * @protocol_id: The protocol being requested.
+ *
+ * Explicitly release a protocol hold previously obtained calling the above
+ * @scmi_devm_get_protocol_ops.
+ */
+static void scmi_devm_put_protocol_ops(struct scmi_device *sdev, u8 protocol_id)
+{
+ int ret;
+
+ ret = devres_release(&sdev->dev, scmi_devm_release_protocol,
+ scmi_devm_protocol_match, &protocol_id);
+ WARN_ON(ret);
+}
+
/**
* scmi_handle_get() - Get the SCMI handle for a device
*
@@ -1004,6 +1126,10 @@ static int scmi_probe(struct platform_device *pdev)
handle = &info->handle;
handle->dev = info->dev;
handle->version = &info->version;
+ handle->devm_get_ops = scmi_devm_get_protocol_ops;
+ handle->devm_put_ops = scmi_devm_put_protocol_ops;
+ handle->get_ops = scmi_get_protocol_operations;
+ handle->put_ops = scmi_release_protocol;
Why do you need a dev_res version and a non dev_res version? I checked
patch 6 where you convert the drivers to use these hooks and all of them
are using the dev res apis.
Yes indeed, I wanted to drop the non devm_ version, but I was not sure
if for completeness I should have instead not provided...So I left it
to have it discussed on the list...I was hoping to be told to remove
those non devres :D
Also because in fact any current or future SCMI driver (that are the only
possible users of this interface) will certainly have an scmi_dev to use
with devm_() methods.
Probably the same is true for notify_ops, I could stick with the new
devres managed versions.
I think you should drop it, unless any one else has issues not having it.
--
Warm Regards
Thara