From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.11]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1A6FB3AB29E; Fri, 14 Aug 2026 11:52:47 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.175.65.11 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786708370; cv=none; b=hpqh69+rKxB/2CKpS/KlEdSwkW961L7kxQV+pam5epuN/YUNPrNNmfvFmKA/mcbS8MIODj3YGjylfiXO69OgT7Odx7QIkpib4NVi9w5O6xTB7ySFEm//yMK4yugD6+yGzmgjzdVkSwpBVlgXo0dWASmYVWPd/K0mgkaXNjgsu/I= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786708370; c=relaxed/simple; bh=FcdBGUrzl0QCcbxTJeDlANFo3txBB5VqLaqK7VwOQ/w=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=dwgMiiWR7aG/GevaTDRdlXfMeAKR5ioKwKRKnSTz2JC8dKNVh3xlBEh3fD1WBty3tMxFozeRJ9X1q6glgvYGENX9MdL/nESpYeDPBpRYIIPanX4hXzbHaF1VZN7N37c9EEZ5Iry2clmfLunfcYOByH8PQZ6Bq862bkDd6bid20g= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com; spf=pass smtp.mailfrom=linux.intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=lDhzPN7Q; arc=none smtp.client-ip=198.175.65.11 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="lDhzPN7Q" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1786708369; x=1818244369; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=FcdBGUrzl0QCcbxTJeDlANFo3txBB5VqLaqK7VwOQ/w=; b=lDhzPN7QO3y4mk6uf0i5IrYcJ42qbh8jDU/uBokyuuAVTtcmr2H7HPMS YMtBY7WHTRLdFk85mZ44eJ6Yh7tNUBMKZ9ioAfUF9NkRB82RikFL0SNwp 5HIg001Wb/OeOpCaIEBrTiSPdm4aUdR1GCuBXFRa1BTTJYCf6aFRCW9D8 xhwZinqcgiRvddcR4zq+El5koA/NaJLF+veGdb/3+jN9txLWGXd/wJudX K7VBm+VA/9YhuUKtUwESWGkMB2Xrmq5AJL1FpkTah9EKYNsppRZTH3tJj CmC3X6bKVyynyF7XHUaCy90+VFB9sCnR8+u9/DUsujFis4hZ4MC8DeHCR g==; X-CSE-ConnectionGUID: +crRLpoAR9CBpcuJsvC0DQ== X-CSE-MsgGUID: qT98ekwZRJG1COEOt2WB3Q== X-IronPort-AV: E=McAfee;i="6800,10657,11874"; a="97631296" X-IronPort-AV: E=Sophos;i="6.25,222,1779174000"; d="scan'208";a="97631296" Received: from fmviesa007.fm.intel.com ([10.60.135.147]) by orvoesa103.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 14 Aug 2026 04:52:48 -0700 X-CSE-ConnectionGUID: OEG5i7VXRa2w3uS+FUOKVg== X-CSE-MsgGUID: 7GrVpiJ7SPCzZpkOP6CRNg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.25,222,1779174000"; d="scan'208";a="260936894" Received: from mkosciow-mobl1.ger.corp.intel.com (HELO localhost) ([10.245.244.134]) by fmviesa007-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 14 Aug 2026 04:52:45 -0700 Date: Fri, 14 Aug 2026 14:52:42 +0300 From: Andy Shevchenko To: Long Zhao Cc: Greg Kroah-Hartman , Jiri Slaby , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Linus Walleij , Ilpo =?iso-8859-1?Q?J=E4rvinen?= , "linux-kernel@vger.kernel.org" , "linux-serial@vger.kernel.org" , "devicetree@vger.kernel.org" Subject: Re: [EXT] Re: [PATCH v3 2/2] serial: 8250_dw: add Ambarella CV75 quirks Message-ID: References: <20260813-cv75-v3-c-v3-0-9352b3fd6026@ambarella.com> <20260813-cv75-v3-c-v3-2-9352b3fd6026@ambarella.com> Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Organization: Intel Finland Oy - BIC 0357606-4 - c/o Alberga Business Park, 6 krs, Bertel Jungin Aukio 5, 02600 Espoo On Fri, Aug 14, 2026 at 09:33:45AM +0000, Long Zhao wrote: > From: Andy Shevchenko > Sent: Friday, August 14, 2026 16:56 > On Thu, Aug 13, 2026 at 06:35:13PM +0800, Long Zhao via B4 Relay wrote: > > > Add CV75 platform data with an ETOI IER mask and skip-set-rate so the > > DesignWare 8250 driver can drive the Ambarella UART for console use. > Thanks for the review. Agreed the commit message was too brief. ... > > + /* Keep variant-specific bits in the shadow across subsequent > > +updates. */ > > This says what code is doing. Instead it must say "why?" the code is doing this. > > > + up->ier |= d->pdata->ier_mask; > > + serial_port_out(p, UART_IER, up->ier); ... > In case there is an HW bug, where can we get the errata, please? (For a bare > minimum add a reference to the Errata document you give to the customers.) > This is not a silicon erratum. The Ambarella UART is not Synopsys > DesignWare IP; it is an Ambarella 8250-compatible UART. We still use > the snps-dw-apb-uart binding / 8250_dw because the programming model > matches closely enough, with two quirks (ETOI IER bit and > SKIP_SET_RATE). I will expand the commit message and rewrite the > comment to explain why in the next revision. Okay, what does it make to think that 8250_dw is a suitable choice? What are the features that are repetitive would be if you use a custom 8250-based driver (using the generic 8250 code)? -- With Best Regards, Andy Shevchenko