From:
C, Ramalingam
Sent: Thursday, December 20, 2018 18:00
To: Daniel Vetter <daniel@xxxxxxxx>; Winkler, Tomas <tomas.winkler@xxxxxxxxx>
Cc: Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx>; Rafael J. Wysocki <rafael@xxxxxxxxxx>; intel-gfx <intel-gfx@xxxxxxxxxxxxxxxxxxxxx>; dri-devel <dri-devel@xxxxxxxxxxxxxxxxxxxxx>; Sean Paul <seanpaul@xxxxxxxxxxxx>; Shankar, Uma <uma.shankar@xxxxxxxxx>; Syrjala,
Ville <ville.syrjala@xxxxxxxxxxxxxxx>; Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Subject: Re: [PATCH v9 35/39] misc/mei/hdcp: Component framework for I915 Interface
On 12/19/2018 12:15 PM, C, Ramalingam wrote:
Tomas and Daniel,
From the discussion on this thread, I infer following understanding:
-
At present(v9) I915 wants to be hard binded to mei_hdcp device-driver binding status through components
-
This means I915 driver load will get complete only when the mei_hdcp's device and driver are bound.
-
if mei_hdcp device reset I915 will unregister itself from userspace, and wait for the mei_hdcp device-deriver rebinding.
-
Could be due to FW error or any unexpected failures those are rare occurances.
-
when mei_hdcp module is removed i915 will unregister itself.
-
Becasue of this, Ideally I915 dont expect the device reset from mei for suspend and resume.
-
At present Mei bus is designed as below:
-
Device will disappear on FW failures, FW upgrade, suspend of the system etc.
-
And when the errors are handled or on system resume mei device will reappear, hence binding with corresponding driver.
-
Mei doesn't plan to avoid the device reset(disappearance and reappearance) for suspend and resume in near future.
Based on above understanding, I propose the below approach. Please correct or approve it.
-
At present(v9) component_add from mei_hdcp indicates the mei_hdcp's device-driver binded state.
-
Instead lets use component to indicate the mei_hdcp's module availability,
-
by adding the component at module_init and removing it from module_exit.
-
This way I915 will not be impacted due to the mei device reset at suspend.
-
In such scenario I915 will have no idea about the device-driver bind status of mei_hdcp.
-
So incase of device is not available, mei_hdcp is responsible to prune such calls with -EIO error.
-
This approach avoid any future impact to I915, incase mei intended to support suspend and resume.
I am aware this is not the ideal solution we want. But I feel this is the best at present we could do for this I915-mei interface.
Best regards,
Ram
something like (un compiled code)
diff --git a/drivers/misc/mei/hdcp/mei_hdcp.c b/drivers/misc/mei/hdcp/mei_hdcp.c
index b22a71e8c5d7..b5b57a883e3b 100644
--- a/drivers/misc/mei/hdcp/mei_hdcp.c
+++ b/drivers/misc/mei/hdcp/mei_hdcp.c
@@ -23,11 +23,15 @@
#include <linux/slab.h>
#include <linux/uuid.h>
#include <linux/mei_cl_bus.h>
+#include <linux/component.h>
#include <drm/drm_connector.h>
#include <drm/i915_component.h>
#include "mei_hdcp.h"
+struct i915_component_master *i915_master_comp;
+static bool mei_hdcp_component_registered;
+
/**
* mei_initiate_hdcp2_session() - Initiate a Wired HDCP2.2 Tx Session in ME FW
* @dev: device corresponding to the mei_cl_device
@@ -691,8 +695,7 @@ mei_close_hdcp_session(struct device *dev, struct hdcp_port_data *data)
return 0;
}
-static __attribute__((unused))
-struct i915_hdcp_component_ops mei_hdcp_ops = {
+static struct i915_hdcp_component_ops mei_hdcp_ops = {
.owner = THIS_MODULE,
.initiate_hdcp2_session = mei_initiate_hdcp2_session,
.verify_receiver_cert_prepare_km = mei_verify_receiver_cert_prepare_km,
@@ -707,20 +710,84 @@ struct i915_hdcp_component_ops mei_hdcp_ops = {
.close_hdcp_session = mei_close_hdcp_session,
};
+static int mei_hdcp_component_bind(struct device *mei_kdev,
+ struct device *i915_kdev, void *data)
+{
+ struct i915_component_master *master_comp = data;
+
+ dev_info(mei_kdev, "MEI HDCP comp bind\n");
+ WARN_ON(master_comp->hdcp_ops);
+ master_comp->hdcp_ops = &mei_hdcp_ops;
+ master_comp->mei_dev = mei_kdev;
+
+ i915_master_comp = master_comp;
+
+ return 0;
+}
+
+static void mei_hdcp_component_unbind(struct device *mei_kdev,
+ struct device *i915_kdev, void *data)
+{
+ struct i915_component_master *master_comp = data;
+
+ dev_info(mei_kdev, "MEI HDCP comp unbind\n");
+ master_comp->hdcp_ops = NULL;
+ master_comp->mei_dev = NULL;
+ i915_master_comp = NULL;
+}
+
+static const struct component_ops mei_hdcp_component_bind_ops = {
+ .bind = mei_hdcp_component_bind,
+ .unbind = mei_hdcp_component_unbind,
+};
+
+static void mei_hdcp_component_init(struct device *dev)
+{
+ int ret;
+
+ if (mei_hdcp_component_registered && i915_master_comp) {
+ i915_master_comp->mei_dev = dev;
+ return;
+ }
+
+ dev_info(dev, "MEI HDCP comp init\n");
+ ret = component_add(dev, &mei_hdcp_component_bind_ops);
+ if (ret < 0) {
+ dev_err(dev, "Failed to add MEI HDCP comp (%d)\n", ret);
+ return;
+ }
+
+ mei_hdcp_component_registered = true;
+}
+
+static void mei_hdcp_component_cleanup(struct device *dev)
+{
+ if (!mei_hdcp_component_registered)
+ return;
+
+ dev_info(dev, "MEI HDCP comp cleanup\n");
+ component_del(dev, &mei_hdcp_component_bind_ops);
+ mei_hdcp_component_registered = false;
+}
+
static int mei_hdcp_probe(struct mei_cl_device *cldev,
const struct mei_cl_device_id *id)
{
int ret;
ret = mei_cldev_enable(cldev);
- if (ret < 0)
+ if (ret < 0) {
dev_err(&cldev->dev, "mei_cldev_enable Failed. %d\n", ret);
+ return ret;
+ }
+ mei_hdcp_component_init(&cldev->dev);
- return ret;
+ return 0;
}
static int mei_hdcp_remove(struct mei_cl_device *cldev)
{
+ i915_master_comp->mei_dev = NULL;
return mei_cldev_disable(cldev);
}
@@ -741,7 +808,23 @@ static struct mei_cl_driver mei_hdcp_driver = {
.remove = mei_hdcp_remove,
};
-module_mei_cl_driver(mei_hdcp_driver);
+static int __init mei_hdcp_init(void)
+{
+ int ret;
+
+ ret = mei_cldev_driver_register(mei_hdcp_driver);
+ if (ret)
+ return ret;
+}
+
+static void __exit mei_hdcp_exit(void)
+{
+ mei_hdcp_component_cleanup(&cldev->dev);
Don’t think you can do that, no guarantees this will be valid pointer
+ mei_cldev_driver_unregister(mei_hdcp_driver);
+}
+
+module_init(mei_hdcp_init);
+module_exit(mei_hdcp_exit);
MODULE_AUTHOR("Intel Corporation");
MODULE_LICENSE("Dual BSD/GPL");
--
2.7.4
-Ram
