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 > o This means I915 driver load will get complete only when the > mei_hdcp's device and driver are bound. > o 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. > o when mei_hdcp module is removed i915 will unregister itself. > o Becasue of this, Ideally I915 dont expect the device reset > from mei for suspend and resume. > * At present Mei bus is designed as below: > o Device will disappear on FW failures, FW upgrade, suspend of > the system etc. > o 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, > o 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. > o 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 #include #include +#include #include #include #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); + 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