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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 9F0CBC3601E for ; Tue, 17 Sep 2024 13:58:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=jecH/p+s4cVp8cVZ3BXs0vP3dWaGdtEpKGnaGgkaZMM=; b=LBtY9yDIoAMYBA IE4bbqrCQCh8XfR4VuWsWaNQAQuJOrT34S7GG/D6QH1ijyK4yZFm9wTg4zXwPyVg9w5/vuEJfFDqr tAbPh4VcafFDDiJWaZICAZNP+AhloOqfXIaIxvY1zI3s9YYRi4mr7m6HQJBQ1qyxEwEWW5MxRuOTe DxQYnPm6Pm7Y3itB4ZZjnPlaMJhM3LSE0Tj60UT+OnPt+Zcylmq3jESxc9g4JTRMkFaUPJs8T/V4D lydelHGMtIU4CtN+s0g4CKIrm58DbVLhjyVKQDpJErmP64rli72zTEdfk+vhNbCtMu6nVFl3OqkSr ir0q5GajOiycakquuBUw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1sqYj7-00000006Gtd-2XpC; Tue, 17 Sep 2024 13:58:45 +0000 Received: from mgamail.intel.com ([198.175.65.16]) by bombadil.infradead.org with esmtps (Exim 4.98 #2 (Red Hat Linux)) id 1sqYj4-00000006GtE-1w4q for linux-riscv@lists.infradead.org; Tue, 17 Sep 2024 13:58:43 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1726581523; x=1758117523; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=ZXeO3cCGpQp8km56A8jsnfTWizOI32RKsbTpSpPVZrM=; b=E4yB86KRVjEe5Ms0VFY298YXHLURFDig19oD28PTWwAUWFteJewatiEW 4SVeIwGMOoV3szNaLgb5O1G7CPRRZbcnhuU/VVAfRNKaKYsOyAx//f7FA kd2irkQ7yOjiQMCjOGIhc9rpDtDKstl8OIcndzXuWoIULvNTcIUBrWnEk 5K6tlO88g7/UD9GWwGMAIfIbSMrGv1CEmx6k06sXZBjoMChBDxftBcD/+ hMs9r05+7IZIaAUTWVxgXssicvUwNfqw8InEK9b0vo5xregLh8fm3BhYO DuxodQyhyJuk2Cp6ol9TZd4yOhIz+8n5ZCmQ09XNyxX+L4HaNbd0Lyl07 Q==; X-CSE-ConnectionGUID: cvVwbTjoRrmPABTOmesCtA== X-CSE-MsgGUID: kYfKR6FGQWeiT2JuqsrC5g== X-IronPort-AV: E=McAfee;i="6700,10204,11198"; a="25538896" X-IronPort-AV: E=Sophos;i="6.10,235,1719903600"; d="scan'208";a="25538896" Received: from fmviesa001.fm.intel.com ([10.60.135.141]) by orvoesa108.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 17 Sep 2024 06:58:41 -0700 X-CSE-ConnectionGUID: DrsjfDWiQXS1CygqQkRpgQ== X-CSE-MsgGUID: +42bj6NxTM6E86iNmlIkXg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.10,235,1719903600"; d="scan'208";a="100036764" Received: from smile.fi.intel.com ([10.237.72.54]) by fmviesa001.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 17 Sep 2024 06:58:38 -0700 Received: from andy by smile.fi.intel.com with local (Exim 4.98) (envelope-from ) id 1sqYix-00000009q6z-1l1f; Tue, 17 Sep 2024 16:58:35 +0300 Date: Tue, 17 Sep 2024 16:58:35 +0300 From: Andy Shevchenko To: Palmer Dabbelt Subject: Re: [PATCH] serial: 8250_platform: Enable generic 16550A platform devices Message-ID: References: <20240730051218.767580-1-sunilvl@ventanamicro.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240917_065842_583391_28E564DD X-CRM114-Status: GOOD ( 17.05 ) X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: apatel@ventanamicro.com, Greg KH , linux-kernel@vger.kernel.org, andrei.warkentin@intel.com, linux-serial@vger.kernel.org, linux-riscv@lists.infradead.org, dfustini@tenstorrent.com, jirislaby@kernel.org, ajones@ventanamicro.com Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org On Tue, Sep 17, 2024 at 06:10:25AM -0700, Palmer Dabbelt wrote: > On Mon, 29 Jul 2024 22:12:18 PDT (-0700), Sunil V L wrote: > > Currently, 8250_platform driver is used only for devices with fixed > > serial ports (plat_serial8250_port). Extend this driver for any generic > > 16550A platform devices which can be probed using standard hardware > > discovery mechanisms like ACPI. > > > > This is required in particular for RISC-V which has non-PNP generic > > 16550A compatible UART that needs to be enumerated as ACPI platform > > device. > It seems a bit awkward that we need something RISC-V specific here. I > guess the idea is that we don't want to depend on PNP because we'd end > up with a bunch of PCI dependencies as well? That seems like kind of an > odd way to do things, but I'm frequently suprised by ACPI stuff so We have the same for HSUART on Intel (see 8250_dw.c). The ACPI devices use different approach than PNP. PNP has the exact requirements for compatibility with the legacy UARTs (to some extend). It puts some limitations. I believe having specifics for RISC-V is fine. But I haven't checked the real IP used in the SoC. If it's one that we have the existing driver for (like again mentioned 8250_dw.c), then it should be added there. TL;DR: so, what is the IP is in hardware for UART? Custom? -- With Best Regards, Andy Shevchenko _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv