From 9272a0797833eec27403eaa2ccfcf3a4c9283607 Mon Sep 17 00:00:00 2001 From: Tomas Winkler Date: Thu, 12 Dec 2019 10:41:03 +0200 Subject: [PATCH] mei: hdcp: bind only with i915 on the same PCH commit 1e8d19d9b0dfcf11b61bac627203a290577e807a upstream. The mei device and i915 must reside on the same PCH in order for HDCP to work. Make the component matching function enforce this requirement. hdcp | i915 mei | | +----= PCH =----+ Cc: v5.0+ Cc: Ramalingam C Signed-off-by: Tomas Winkler Reviewed-by: Alexander Usyskin Link: https://lore.kernel.org/r/20191212084103.2893-1-tomas.winkler@intel.com Signed-off-by: Greg Kroah-Hartman --- drivers/misc/mei/hdcp/mei_hdcp.c | 33 +++++++++++++++++++++++++++++--- 1 file changed, 30 insertions(+), 3 deletions(-) diff --git a/drivers/misc/mei/hdcp/mei_hdcp.c b/drivers/misc/mei/hdcp/mei_hdcp.c index c681f6fab342..a9793ea6933b 100644 --- a/drivers/misc/mei/hdcp/mei_hdcp.c +++ b/drivers/misc/mei/hdcp/mei_hdcp.c @@ -758,11 +758,38 @@ static const struct component_master_ops mei_component_master_ops = { .unbind = mei_component_master_unbind, }; +/** + * mei_hdcp_component_match - compare function for matching mei hdcp. + * + * The function checks if the driver is i915, the subcomponent is HDCP + * and the grand parent of hdcp and the parent of i915 are the same + * PCH device. + * + * @dev: master device + * @subcomponent: subcomponent to match (I915_COMPONENT_HDCP) + * @data: compare data (mei hdcp device) + * + * Return: + * * 1 - if components match + * * 0 - otherwise + */ static int mei_hdcp_component_match(struct device *dev, int subcomponent, void *data) { - return !strcmp(dev->driver->name, "i915") && - subcomponent == I915_COMPONENT_HDCP; + struct device *base = data; + + if (strcmp(dev->driver->name, "i915") || + subcomponent != I915_COMPONENT_HDCP) + return 0; + + base = base->parent; + if (!base) + return 0; + + base = base->parent; + dev = dev->parent; + + return (base && dev && dev == base); } static int mei_hdcp_probe(struct mei_cl_device *cldev, @@ -786,7 +813,7 @@ static int mei_hdcp_probe(struct mei_cl_device *cldev, master_match = NULL; component_match_add_typed(&cldev->dev, &master_match, - mei_hdcp_component_match, comp_master); + mei_hdcp_component_match, &cldev->dev); if (IS_ERR_OR_NULL(master_match)) { ret = -ENOMEM; goto err_exit;