From patchwork Mon Sep 30 23:09:56 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lyude Paul X-Patchwork-Id: 13817266 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id DBE33CEB2CD for ; Mon, 30 Sep 2024 23:39:11 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 60E8110E598; Mon, 30 Sep 2024 23:39:11 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (1024-bit key; unprotected) header.d=redhat.com header.i=@redhat.com header.b="AtrJZ9xb"; dkim-atps=neutral Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by gabe.freedesktop.org (Postfix) with ESMTPS id 830EF10E598 for ; Mon, 30 Sep 2024 23:39:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1727739546; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=j6rI5OuJT5Uhwr5YsNsmFqxJRozJhSEgscnGrLzTJHQ=; b=AtrJZ9xb7t4DElm5VkHqkW+K9yIcTDPWmPdcOoqQQbSM3rSZv6WqHlkc8E8DYjF1sCogQE lHriig8jURirmrhU5XBJMpOT1P8hZ2kiXQNXLIUJoeQaWMNyJPcqTYAenPOtqbLjztWnGJ DaNgZxmNWBlmWJILfYXpWfj5NRIgZkE= Received: from mx-prod-mc-01.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-54-T22mXw6dOM2PCD_MgYanjg-1; Mon, 30 Sep 2024 19:39:05 -0400 X-MC-Unique: T22mXw6dOM2PCD_MgYanjg-1 Received: from mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (unknown [10.30.177.4]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id E91D6196A122; Mon, 30 Sep 2024 23:39:02 +0000 (UTC) Received: from chopper.redhat.com (unknown [10.22.32.36]) by mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 25EDD3003DEC; Mon, 30 Sep 2024 23:38:58 +0000 (UTC) From: Lyude Paul To: dri-devel@lists.freedesktop.org, rust-for-linux@vger.kernel.org Cc: Asahi Lina , Danilo Krummrich , mcanal@igalia.com, airlied@redhat.com, zhiw@nvidia.com, cjia@nvidia.com, jhubbard@nvidia.com, Miguel Ojeda , Alex Gaynor , Wedson Almeida Filho , Boqun Feng , Gary Guo , =?utf-8?q?Bj=C3=B6rn_Roy_Baron?= , Benno Lossin , Andreas Hindborg , Alice Ryhl , Trevor Gross , linux-kernel@vger.kernel.org (open list) Subject: [WIP RFC v2 13/35] WIP: rust: drm/kms: Add OpaqueConnector and OpaqueConnectorState Date: Mon, 30 Sep 2024 19:09:56 -0400 Message-ID: <20240930233257.1189730-14-lyude@redhat.com> In-Reply-To: <20240930233257.1189730-1-lyude@redhat.com> References: <20240930233257.1189730-1-lyude@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.4 X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" Since we allow drivers to have multiple implementations of DriverConnector and DriverConnectorState (in C, the equivalent of this is having multiple structs which embed drm_connector) - there are some situations we will run into where it's not possible for us to know the corresponding DriverConnector or DriverConnectorState for a given connector. The most obvious one is iterating through all connectors on a KMS device. So, take advantage of the various connector traits we added to introduce OpaqueConnector<> and OpaqueConnectorState<> which both can be used as a DRM connector and connector state respectively without needing to know the corresponding traits. Signed-off-by: Lyude Paul --- TODO: * Add upcast functions for these types Signed-off-by: Lyude Paul --- rust/kernel/drm/kms/connector.rs | 108 +++++++++++++++++++++++++++++++ 1 file changed, 108 insertions(+) diff --git a/rust/kernel/drm/kms/connector.rs b/rust/kernel/drm/kms/connector.rs index ec842ebc111ae..98ac7fb781d4e 100644 --- a/rust/kernel/drm/kms/connector.rs +++ b/rust/kernel/drm/kms/connector.rs @@ -359,6 +359,64 @@ unsafe fn from_raw<'a>(ptr: *mut bindings::drm_connector) -> &'a Self { T::get_modes(connector.guard(&guard), &guard) } +/// A [`struct drm_connector`] without a known [`DriverConnector`] implementation. +/// +/// This is mainly for situations where our bindings can't infer the [`DriverConnector`] +/// implementation for a [`struct drm_connector`] automatically. It is identical to [`Connector`], +/// except that it does not provide access to the driver's private data. +/// +/// TODO: Add upcast methods for this +/// +/// # Invariants +/// +/// - `connector` is initialized for as long as this object is exposed to users. +/// - The data layout of this type is equivalent to [`struct drm_connector`]. +/// +/// [`struct drm_connector`]: srctree/include/drm/drm_connector.h +#[repr(transparent)] +pub struct OpaqueConnector { + connector: Opaque, + _p: PhantomData +} + +impl Sealed for OpaqueConnector {} + +impl AsRawConnector for OpaqueConnector { + type Driver = T; + type State = OpaqueConnectorState; + + fn as_raw(&self) -> *mut bindings::drm_connector { + self.connector.get() + } + + unsafe fn from_raw<'a>(ptr: *mut bindings::drm_connector) -> &'a Self { + // SAFETY: Our data layout is identical to `bindings::drm_connector` + unsafe { &*ptr.cast() } + } +} + +impl ModeObject for OpaqueConnector { + type Driver = T; + + fn drm_dev(&self) -> &Device { + // SAFETY: The parent device for a DRM connector will never outlive the connector, and this + // pointer is invariant through the lifetime of the connector + unsafe { Device::borrow((*self.as_raw()).dev) } + } + + fn raw_mode_obj(&self) -> *mut bindings::drm_mode_object { + // SAFETY: We don't expose DRM connectors to users before `base` is initialized + unsafe { &mut (*self.as_raw()).base } + } +} + +// SAFETY: Connectors are reference counted mode objects +unsafe impl RcModeObject for OpaqueConnector {} + +// SAFETY: Our connector interfaces are guaranteed to be thread-safe +unsafe impl Send for OpaqueConnector {} +unsafe impl Sync for OpaqueConnector {} + /// A privileged [`Connector`] obtained while holding a [`ModeConfigGuard`]. /// /// This provides access to various methods for [`Connector`] that must happen under lock, such as @@ -537,6 +595,56 @@ unsafe fn from_raw_mut<'a>(ptr: *mut bindings::drm_connector_state) -> &'a mut S } } +/// A [`struct drm_connector_state`] without a known [`DriverConnectorState`] implementation. +/// +/// This is mainly for situations where our bindings can't infer the [`DriverConnectorState`] +/// implementation for a [`struct drm_connector_state`] automatically. It is identical to +/// [`Connector`], except that it does not provide access to the driver's private data. +/// +/// TODO: Add upcast functions +/// +/// # Invariants +/// +/// - `state` is initialized for as long as this object is exposed to users. +/// - The data layout of this type is identical to [`struct drm_connector_state`]. +/// - The DRM C API and our interface guarantees that only the user has mutable access to `state`, +/// up until [`drm_atomic_helper_commit_hw_done`] is called. Therefore, `connector` follows rust's +/// data aliasing rules and does not need to be behind an [`Opaque`] type. +/// +/// [`struct drm_connector_state`]: srctree/include/drm/drm_connector.h +/// [`drm_atomic_helper_commit_hw_done`]: srctree/include/drm/drm_atomic_helper.h +#[repr(transparent)] +pub struct OpaqueConnectorState { + state: bindings::drm_connector_state, + _p: PhantomData +} + +impl AsRawConnectorState for OpaqueConnectorState { + type Connector = OpaqueConnector; +} + +impl private::AsRawConnectorState for OpaqueConnectorState { + fn as_raw(&self) -> &bindings::drm_connector_state { + &self.state + } + + unsafe fn as_raw_mut(&mut self) -> &mut bindings::drm_connector_state { + &mut self.state + } +} + +impl FromRawConnectorState for OpaqueConnectorState { + unsafe fn from_raw<'a>(ptr: *const bindings::drm_connector_state) -> &'a Self { + // SAFETY: Our data layout is identical to `bindings::drm_connector_state` + unsafe { &*ptr.cast() } + } + + unsafe fn from_raw_mut<'a>(ptr: *mut bindings::drm_connector_state) -> &'a mut Self { + // SAFETY: Our data layout is identical to `bindings::drm_connector_state` + unsafe { &mut *ptr.cast() } + } +} + unsafe extern "C" fn atomic_duplicate_state_callback( connector: *mut bindings::drm_connector ) -> *mut bindings::drm_connector_state