From mboxrd@z Thu Jan 1 00:00:00 1970 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0825FC3DA7D for ; Wed, 28 Dec 2022 15:35:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233247AbiL1PfI (ORCPT ); Wed, 28 Dec 2022 10:35:08 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52668 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233868AbiL1PfG (ORCPT ); Wed, 28 Dec 2022 10:35:06 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CDAFB164AE for ; Wed, 28 Dec 2022 07:35:05 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 833AEB81647 for ; Wed, 28 Dec 2022 15:35:04 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id DBC35C433D2; Wed, 28 Dec 2022 15:35:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1672241703; bh=O2UZt/D8iRl4mCvJNm26WOqTGnZ0ZCFMgQY6QpAQZPU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=2tcJydUVC+TPLKipsRWhNC1KJdczueBueKrIKJUmgXZgxcBmI9Mu4XV/oKTZXkMLJ w1/YeENhD6IqxjyzJM8gzkLkaobFrfXmjnHw36KNo6I3Y5H54bz++nmS3Db1Gqmo4Q rs19rDXJ3W1JxrUkkueGO65AmmjD3/9+dNg0mWSw= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Marco Felsch , Marek Vasut , Sasha Levin Subject: [PATCH 6.1 0267/1146] drm: lcdif: change burst size to 256B Date: Wed, 28 Dec 2022 15:30:06 +0100 Message-Id: <20221228144337.386885082@linuxfoundation.org> X-Mailer: git-send-email 2.39.0 In-Reply-To: <20221228144330.180012208@linuxfoundation.org> References: <20221228144330.180012208@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Marco Felsch [ Upstream commit 2215cb3be5c28a1fd43036550c00c2371aeeba95 ] If a axi bus master with a higher priority do a lot of memory access FIFO underruns can be inspected. Increase the burst size to 256B to avoid such underruns and to improve the memory access efficiency. Fixes: 9db35bb349a0 ("drm: lcdif: Add support for i.MX8MP LCDIF variant") Signed-off-by: Marco Felsch Reviewed-by: Marek Vasut Signed-off-by: Marek Vasut Link: https://patchwork.freedesktop.org/patch/msgid/20221101164615.778299-1-m.felsch@pengutronix.de Signed-off-by: Sasha Levin --- drivers/gpu/drm/mxsfb/lcdif_kms.c | 14 ++++++++++++-- drivers/gpu/drm/mxsfb/lcdif_regs.h | 4 ++++ 2 files changed, 16 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/mxsfb/lcdif_kms.c b/drivers/gpu/drm/mxsfb/lcdif_kms.c index 9f212e29059b..d594938a6c8d 100644 --- a/drivers/gpu/drm/mxsfb/lcdif_kms.c +++ b/drivers/gpu/drm/mxsfb/lcdif_kms.c @@ -148,8 +148,18 @@ static void lcdif_set_mode(struct lcdif_drm_private *lcdif, u32 bus_flags) CTRLDESCL0_1_WIDTH(m->hdisplay), lcdif->base + LCDC_V8_CTRLDESCL0_1); - writel(CTRLDESCL0_3_PITCH(lcdif->crtc.primary->state->fb->pitches[0]), - lcdif->base + LCDC_V8_CTRLDESCL0_3); + /* + * Undocumented P_SIZE and T_SIZE register but those written in the + * downstream kernel those registers control the AXI burst size. As of + * now there are two known values: + * 1 - 128Byte + * 2 - 256Byte + * Downstream set it to 256B burst size to improve the memory + * efficiency so set it here too. + */ + ctrl = CTRLDESCL0_3_P_SIZE(2) | CTRLDESCL0_3_T_SIZE(2) | + CTRLDESCL0_3_PITCH(lcdif->crtc.primary->state->fb->pitches[0]); + writel(ctrl, lcdif->base + LCDC_V8_CTRLDESCL0_3); } static void lcdif_enable_controller(struct lcdif_drm_private *lcdif) diff --git a/drivers/gpu/drm/mxsfb/lcdif_regs.h b/drivers/gpu/drm/mxsfb/lcdif_regs.h index c70220651e3a..8e8bef175bf2 100644 --- a/drivers/gpu/drm/mxsfb/lcdif_regs.h +++ b/drivers/gpu/drm/mxsfb/lcdif_regs.h @@ -190,6 +190,10 @@ #define CTRLDESCL0_1_WIDTH(n) ((n) & 0xffff) #define CTRLDESCL0_1_WIDTH_MASK GENMASK(15, 0) +#define CTRLDESCL0_3_P_SIZE(n) (((n) << 20) & CTRLDESCL0_3_P_SIZE_MASK) +#define CTRLDESCL0_3_P_SIZE_MASK GENMASK(22, 20) +#define CTRLDESCL0_3_T_SIZE(n) (((n) << 16) & CTRLDESCL0_3_T_SIZE_MASK) +#define CTRLDESCL0_3_T_SIZE_MASK GENMASK(17, 16) #define CTRLDESCL0_3_PITCH(n) ((n) & 0xffff) #define CTRLDESCL0_3_PITCH_MASK GENMASK(15, 0) -- 2.35.1