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 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 02D53C04A68 for ; Wed, 27 Jul 2022 13:22:59 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id E8884C5789; Wed, 27 Jul 2022 13:22:58 +0000 (UTC) Received: from perceval.ideasonboard.com (perceval.ideasonboard.com [213.167.242.64]) by gabe.freedesktop.org (Postfix) with ESMTPS id BC42AC4DF5 for ; Wed, 27 Jul 2022 13:22:56 +0000 (UTC) Received: from [192.168.1.111] (91-158-154-79.elisa-laajakaista.fi [91.158.154.79]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 27C74835; Wed, 27 Jul 2022 15:22:54 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1658928174; bh=eotjNVMAx8QGW06uc3w0MIvKkRtcfjCQLq3gxWF/uIQ=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=Q+e5gl73+JqpP0dYQ4eSjNqjCNe4M4TG2Sjx+O2xlDudTYz/i3tKWrWLtynEldDgO Nwmzb60YTLItlupERg3e/OWkyQwRdzR6t4IoGoK4uI22nQijb75Fof+RwTIL873C7/ vlfPQQ8tLDGP1OtT+jfY2n9LJ2C5yvIEYQQF1rVs= Message-ID: <83df99ee-1304-121f-97e6-85ca416aef1f@ideasonboard.com> Date: Wed, 27 Jul 2022 16:22:50 +0300 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.11.0 Subject: Re: [PATCH 8/8] drm/tidss: Enable Dual and Duplicate Modes for OLDI Content-Language: en-US To: Aradhya Bhatia , Jyri Sarha , Rob Herring , David Airlie , Daniel Vetter , Krzysztof Kozlowski References: <20220719080845.22122-1-a-bhatia1@ti.com> <20220719080845.22122-9-a-bhatia1@ti.com> From: Tomi Valkeinen In-Reply-To: <20220719080845.22122-9-a-bhatia1@ti.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit 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: , Cc: Nishanth Menon , Devicetree List , Vignesh Raghavendra , Devarsh Thakkar , Linux Kernel List , DRI Development List , Darren Etheridge , Rahul T R , Krunal Bhargav Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" Hi, On 19/07/2022 11:08, Aradhya Bhatia wrote: > The AM625 DSS peripheral supports 2 OLDI TXes which can work to enable 2 > duplicated displays of smaller resolutions or enable a single Dual-Link > display with a higher resolution (1920x1200). > > Configure the necessary register to enable the different modes. > > Signed-off-by: Aradhya Bhatia > --- > drivers/gpu/drm/tidss/tidss_dispc.c | 44 +++++++++++++++++++++++++++-- > 1 file changed, 41 insertions(+), 3 deletions(-) > > diff --git a/drivers/gpu/drm/tidss/tidss_dispc.c b/drivers/gpu/drm/tidss/tidss_dispc.c > index 0b9689453ee8..28cb61259471 100644 > --- a/drivers/gpu/drm/tidss/tidss_dispc.c > +++ b/drivers/gpu/drm/tidss/tidss_dispc.c > @@ -1021,8 +1021,8 @@ static void dispc_enable_oldi(struct dispc_device *dispc, u32 hw_videoport, > int count = 0; > > /* > - * For the moment DUALMODESYNC, MASTERSLAVE, MODE, and SRC > - * bits of DISPC_VP_DSS_OLDI_CFG are set statically to 0. > + * For the moment MASTERSLAVE, and SRC bits of DISPC_VP_DSS_OLDI_CFG are > + * set statically to 0. > */ > > if (fmt->data_width == 24) > @@ -1039,7 +1039,45 @@ static void dispc_enable_oldi(struct dispc_device *dispc, u32 hw_videoport, > > oldi_cfg |= BIT(0); /* ENABLE */ > > - dispc_vp_write(dispc, hw_videoport, DISPC_VP_DSS_OLDI_CFG, oldi_cfg); > + /* > + * As per all the current implementations of DSS, the OLDI TXes are present only on > + * hw_videoport = 0 (OLDI TX 0). However, the config register for 2nd OLDI TX (OLDI TX 1) > + * is present in the address space of hw_videoport = 1. Hence, using "hw_videoport + 1" to > + * configure OLDI TX 1. > + */ > + > + switch (dispc->oldi_mode) { > + case OLDI_MODE_OFF: > + oldi_cfg &= ~BIT(0); /* DISABLE */ > + dispc_vp_write(dispc, hw_videoport, DISPC_VP_DSS_OLDI_CFG, oldi_cfg); > + dispc_vp_write(dispc, hw_videoport + 1, DISPC_VP_DSS_OLDI_CFG, oldi_cfg); > + break; > + > + case OLDI_SINGLE_LINK_SINGLE_MODE_0: > + dispc_vp_write(dispc, hw_videoport, DISPC_VP_DSS_OLDI_CFG, oldi_cfg); > + break; > + > + case OLDI_SINGLE_LINK_SINGLE_MODE_1: > + dispc_vp_write(dispc, hw_videoport + 1, DISPC_VP_DSS_OLDI_CFG, oldi_cfg); > + break; > + > + case OLDI_SINGLE_LINK_DUPLICATE_MODE: > + oldi_cfg |= BIT(5); /* DUPLICATE MODE */ > + dispc_vp_write(dispc, hw_videoport, DISPC_VP_DSS_OLDI_CFG, oldi_cfg); > + dispc_vp_write(dispc, hw_videoport + 1, DISPC_VP_DSS_OLDI_CFG, oldi_cfg); > + break; > + > + case OLDI_DUAL_LINK: > + oldi_cfg |= BIT(11); /* DUALMODESYNC */ > + dispc_vp_write(dispc, hw_videoport, DISPC_VP_DSS_OLDI_CFG, oldi_cfg); > + dispc_vp_write(dispc, hw_videoport + 1, DISPC_VP_DSS_OLDI_CFG, oldi_cfg); > + break; > + > + default: > + dev_warn(dispc->dev, "%s: Incorrect oldi mode. Returning.\n", > + __func__); > + return; > + } > > while (!(oldi_reset_bit & dispc_read(dispc, DSS_SYSSTATUS)) && > count < 10000) This feels a bit hacky: - The function is dispc_enable_oldi, but the above code also disables oldi. We have code in dispc_vp_unprepare() which disables OLDI at the moment. - The function takes hw_videoport as a parameter, and is designed to work on that videoport. The above operates on two videoports. Isn't the function also called for hw_videoport +1, which would result in reg writes to hw_videoport + 2? - No matching code in dispc_vp_unprepare Obviously the duplicate mode (I presume that's "cloning") and the dual link complicate things here, and I have to say I haven't worked with such setups. But I think somehow this should be restructured so that common configuration (common to the OLDIs) is done somewhere else. I would guess that there are other drivers that support cloning and dual mode. Did you have a look how they handle things? Tomi