From patchwork Fri Sep 20 06:56:26 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Animesh Manna X-Patchwork-Id: 11153843 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 387E31745 for ; Fri, 20 Sep 2019 07:05:02 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 20EE6206C2 for ; Fri, 20 Sep 2019 07:05:02 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 20EE6206C2 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=intel-gfx-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 8D93F6EF44; Fri, 20 Sep 2019 07:05:01 +0000 (UTC) X-Original-To: intel-gfx@lists.freedesktop.org Delivered-To: intel-gfx@lists.freedesktop.org Received: from mga06.intel.com (mga06.intel.com [134.134.136.31]) by gabe.freedesktop.org (Postfix) with ESMTPS id 3024E6F3AC for ; Fri, 20 Sep 2019 07:05:00 +0000 (UTC) X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga005.jf.intel.com ([10.7.209.41]) by orsmga104.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 20 Sep 2019 00:05:00 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.64,527,1559545200"; d="scan'208";a="362764858" Received: from amanna.iind.intel.com ([10.223.74.216]) by orsmga005.jf.intel.com with ESMTP; 20 Sep 2019 00:04:57 -0700 From: Animesh Manna To: intel-gfx@lists.freedesktop.org Date: Fri, 20 Sep 2019 12:26:26 +0530 Message-Id: <20190920065626.3525-11-animesh.manna@intel.com> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20190920065626.3525-1-animesh.manna@intel.com> References: <20190920065626.3525-1-animesh.manna@intel.com> MIME-Version: 1.0 Subject: [Intel-gfx] [PATCH v8 10/10] drm/i915/dsb: Documentation for DSB. X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Jani Nikula Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" Added docbook info regarding Display State Buffer(DSB) which is added from gen12 onwards to batch submit display HW programming. v1: Initial version as RFC. Cc: Jani Nikula Cc: Rodrigo Vivi Cc: Shashank Sharma Reviewed-by: Shashank Sharma Signed-off-by: Animesh Manna --- Documentation/gpu/i915.rst | 9 ++++ drivers/gpu/drm/i915/display/intel_dsb.c | 68 ++++++++++++++++++++++++ 2 files changed, 77 insertions(+) diff --git a/Documentation/gpu/i915.rst b/Documentation/gpu/i915.rst index e249ea7b0ec7..465779670fd4 100644 --- a/Documentation/gpu/i915.rst +++ b/Documentation/gpu/i915.rst @@ -246,6 +246,15 @@ Display PLLs .. kernel-doc:: drivers/gpu/drm/i915/display/intel_dpll_mgr.h :internal: +Display State Buffer +-------------------- + +.. kernel-doc:: drivers/gpu/drm/i915/display/intel_dsb.c + :doc: DSB + +.. kernel-doc:: drivers/gpu/drm/i915/display/intel_dsb.c + :internal: + Memory Management and Command Submission ======================================== diff --git a/drivers/gpu/drm/i915/display/intel_dsb.c b/drivers/gpu/drm/i915/display/intel_dsb.c index 000291c100a0..768841a8883b 100644 --- a/drivers/gpu/drm/i915/display/intel_dsb.c +++ b/drivers/gpu/drm/i915/display/intel_dsb.c @@ -9,6 +9,23 @@ #define DSB_BUF_SIZE (2 * PAGE_SIZE) +/** + * DOC: DSB + * + * A DSB (Display State Buffer) is a queue of MMIO instructions in the memory + * which can be offloaded to DSB HW in Display Controller. DSB HW is a DMA + * engine that can be programmed to download the DSB from memory. + * It allows driver to batch submit display HW programming. This helps to + * reduce loading time and CPU activity, thereby making the context switch + * faster. DSB Support added from Gen12 Intel graphics based platform. + * + * DSB's can access only the pipe, plane, and transcoder Data Island Packet + * registers. + * + * DSB HW can support only register writes (both indexed and direct MMIO + * writes). There are no registers reads possible with DSB HW engine. + */ + /* DSB opcodes. */ #define DSB_OPCODE_SHIFT 24 #define DSB_OPCODE_MMIO_WRITE 0x1 @@ -66,6 +83,17 @@ static inline bool intel_dsb_disable_engine(struct intel_dsb *dsb) return true; } +/** + * intel_dsb_get() - Allocate DSB context and return a DSB instance. + * @crtc: intel_crtc structure to get pipe info. + * + * This function provides handle of a DSB instance, for the further DSB + * operations. + * + * Returns: address of Intel_dsb instance requested for. + * Failure: Returns the same DSB instance, but without a command buffer. + */ + struct intel_dsb * intel_dsb_get(struct intel_crtc *crtc) { @@ -116,6 +144,14 @@ intel_dsb_get(struct intel_crtc *crtc) return dsb; } +/** + * intel_dsb_put() - To destroy DSB context. + * @dsb: intel_dsb structure. + * + * This function destroys the DSB context allocated by a dsb_get(), by + * unpinning and releasing the VMA object associated with it. + */ + void intel_dsb_put(struct intel_dsb *dsb) { struct intel_crtc *crtc = container_of(dsb, typeof(*crtc), dsb); @@ -138,6 +174,19 @@ void intel_dsb_put(struct intel_dsb *dsb) } } +/** + * intel_dsb_indexed_reg_write() -Write to the DSB context for auto + * increment register. + * @dsb: intel_dsb structure. + * @reg: register address. + * @val: value. + * + * This function is used for writing register-value pair in command + * buffer of DSB for auto-increment register. During command buffer overflow, + * a warning is thrown and rest all erroneous condition register programming + * is done through mmio write. + */ + void intel_dsb_indexed_reg_write(struct intel_dsb *dsb, i915_reg_t reg, u32 val) { @@ -202,6 +251,18 @@ void intel_dsb_indexed_reg_write(struct intel_dsb *dsb, i915_reg_t reg, buf[dsb->free_pos] = 0; } +/** + * intel_dsb_reg_write() -Write to the DSB context for normal + * register. + * @dsb: intel_dsb structure. + * @reg: register address. + * @val: value. + * + * This function is used for writing register-value pair in command + * buffer of DSB. During command buffer overflow, a warning is thrown + * and rest all erroneous condition register programming is done + * through mmio write. + */ void intel_dsb_reg_write(struct intel_dsb *dsb, i915_reg_t reg, u32 val) { struct intel_crtc *crtc = container_of(dsb, typeof(*crtc), dsb); @@ -224,6 +285,13 @@ void intel_dsb_reg_write(struct intel_dsb *dsb, i915_reg_t reg, u32 val) i915_mmio_reg_offset(reg); } +/** + * intel_dsb_commit() - Trigger workload execution of DSB. + * @dsb: intel_dsb structure. + * + * This function is used to do actual write to hardware using DSB. + * On errors, fall back to MMIO. Also this function help to reset the context. + */ void intel_dsb_commit(struct intel_dsb *dsb) { struct intel_crtc *crtc = container_of(dsb, typeof(*crtc), dsb);