From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received-SPF: Pass (sender SPF authorized) identity=mailfrom; client-ip=66.187.233.73; helo=mx1.redhat.com; envelope-from=lersek@redhat.com; receiver=edk2-devel@lists.01.org Received: from mx1.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id 28095203BBB80 for ; Thu, 24 May 2018 07:50:33 -0700 (PDT) Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.rdu2.redhat.com [10.11.54.4]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 55A1481902B3; Thu, 24 May 2018 14:50:32 +0000 (UTC) Received: from lacos-laptop-7.usersys.redhat.com (ovpn-121-84.rdu2.redhat.com [10.10.121.84]) by smtp.corp.redhat.com (Postfix) with ESMTP id BB4862026985; Thu, 24 May 2018 14:50:31 +0000 (UTC) To: Ard Biesheuvel Cc: edk2-devel-01 , Jordan Justen References: <20180523202121.8125-1-lersek@redhat.com> <20180523202121.8125-4-lersek@redhat.com> From: Laszlo Ersek Message-ID: <1cef03f3-f3be-9fd6-2644-a16ec95f1949@redhat.com> Date: Thu, 24 May 2018 16:50:31 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.7.0 MIME-Version: 1.0 In-Reply-To: X-Scanned-By: MIMEDefang 2.78 on 10.11.54.4 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.8]); Thu, 24 May 2018 14:50:32 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.8]); Thu, 24 May 2018 14:50:32 +0000 (UTC) for IP:'10.11.54.4' DOMAIN:'int-mx04.intmail.prod.int.rdu2.redhat.com' HELO:'smtp.corp.redhat.com' FROM:'lersek@redhat.com' RCPT:'' Subject: Re: [PATCH v2 3/7] OvmfPkg: introduce PciCapPciIoLib X-BeenThere: edk2-devel@lists.01.org X-Mailman-Version: 2.1.26 Precedence: list List-Id: EDK II Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 24 May 2018 14:50:33 -0000 Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit On 05/24/18 10:13, Ard Biesheuvel wrote: > On 23 May 2018 at 22:21, Laszlo Ersek wrote: >> Add a library class, and a UEFI_DRIVER lib instance, that are layered on >> top of PciCapLib, and allow clients to plug an EFI_PCI_IO_PROTOCOL backend >> into PciCapLib, for config space access. >> >> (Side note: >> > > Again, please retain the below. Will do. >> +STATIC >> +EFI_STATUS >> +ProtoDevTransferConfig ( >> + IN EFI_PCI_IO_PROTOCOL *PciIo, >> + IN EFI_PCI_IO_PROTOCOL_CONFIG TransferFunction, >> + IN UINT16 ConfigOffset, >> + IN OUT UINT8 *Buffer, >> + IN UINT16 Size >> + ) >> +{ >> + while (Size > 0) { >> + EFI_PCI_IO_PROTOCOL_WIDTH Width; >> + UINT16 Count; >> + EFI_STATUS Status; >> + UINT16 Progress; >> + >> + // >> + // Pick the largest access size that is allowed by the remaining transfer >> + // Size and by the alignment of ConfigOffset. >> + // >> + // When the largest access size is available, transfer as many bytes as >> + // possible in one iteration of the loop. Otherwise, transfer only one >> + // unit, to improve the alignment. >> + // >> + if (Size >= BIT2 && (ConfigOffset & (BIT2 - 1)) == 0) { > > Ugh. Just use '4' or sizeof(UINT32). > >> + Width = EfiPciIoWidthUint32; >> + Count = Size >> Width; >> + } else if (Size >= BIT1 && (ConfigOffset & (BIT1 - 1)) == 0) { >> + Width = EfiPciIoWidthUint16; >> + Count = 1; >> + } else { >> + Width = EfiPciIoWidthUint8; >> + Count = 1; >> + } I used "BITx" and "(BITx - 1)" for consistency, and because they seemed to convey the idea well (namely, shifting down the alignment). I'm fine replacing "BIT2" with "4", but then I believe I should also replace "(BIT2 - 1)" with "3". Similarly, replace "BIT1" with "2", and "(BIT1 -1)" with 1. Do you prefer the current code or the decimal constants? Thanks! Laszlo