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 6C49CC678DC for ; Fri, 18 Aug 2023 07:44:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1358238AbjHRHoI (ORCPT ); Fri, 18 Aug 2023 03:44:08 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40602 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1353097AbjHRHnd (ORCPT ); Fri, 18 Aug 2023 03:43:33 -0400 Received: from out4-smtp.messagingengine.com (out4-smtp.messagingengine.com [66.111.4.28]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DF0E030FE; Fri, 18 Aug 2023 00:43:31 -0700 (PDT) Received: from compute5.internal (compute5.nyi.internal [10.202.2.45]) by mailout.nyi.internal (Postfix) with ESMTP id 6A3615C0109; Fri, 18 Aug 2023 03:43:28 -0400 (EDT) Received: from mailfrontend1 ([10.202.2.162]) by compute5.internal (MEProxy); Fri, 18 Aug 2023 03:43:28 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:cc:content-type:content-type:date:date :feedback-id:feedback-id:from:from:in-reply-to:in-reply-to :message-id:mime-version:references:reply-to:sender:subject :subject:to:to:x-me-proxy:x-me-proxy:x-me-sender:x-me-sender :x-sasl-enc; s=fm1; t=1692344608; x=1692431008; bh=dgynFTvpIcFvK Eo0nbMvK3p2F9Xe31fJomXDBpjns84=; b=TpTIbyFzJgFY+xQiL0O6OXZLQFwzq gIQLlb5lIW2WuMN2aJ2lBWXqluX6mIL1wkgQSnMrrVgephGHF7BLk+v0vbSXy/91 zxSgwt7DKzspEYNNUNIj2uLQ/G5dnJCMspoQx20c/MlQA6fLMghNv8yN5Onwk0GO jFlKAAwY2XRH1dtKcx4H2gdW5SR73LoJ7RKiv6Qf43WLOY/uG3x6ZmjGvFU+7GmX iV6hS+X6HJMDw7EoQxnKRR1mu04091qb2KFfwIgK9f820EJWACZR1UEc8ueDQHxi QlIbNaeelrVYm33VI/0ycn/Y8FfOmIrfTq0RB1ljmNiBurrtDyaeP344w== X-ME-Sender: X-ME-Received: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgedviedrudduvddguddvfecutefuodetggdotefrod ftvfcurfhrohhfihhlvgemucfhrghsthforghilhdpqfgfvfdpuffrtefokffrpgfnqfgh necuuegrihhlohhuthemuceftddtnecusecvtfgvtghiphhivghnthhsucdlqddutddtmd enucfjughrpeffhffvvefujgfkfhggtgesthdtredttddtvdenucfhrhhomhephfhinhhn ucfvhhgrihhnuceofhhthhgrihhnsehlihhnuhigqdhmieekkhdrohhrgheqnecuggftrf grthhtvghrnhepleeuheelheekgfeuvedtveetjeekhfffkeeffffftdfgjeevkeegfedv ueehueelnecuvehluhhsthgvrhfuihiivgeptdenucfrrghrrghmpehmrghilhhfrhhomh epfhhthhgrihhnsehlihhnuhigqdhmieekkhdrohhrgh X-ME-Proxy: Feedback-ID: i58a146ae:Fastmail Received: by mail.messagingengine.com (Postfix) with ESMTPA; Fri, 18 Aug 2023 03:43:26 -0400 (EDT) Date: Fri, 18 Aug 2023 17:43:40 +1000 (AEST) From: Finn Thain To: Michael Schmitz cc: dlemoal@kernel.org, linux-ide@vger.kernel.org, linux-m68k@vger.kernel.org, will@sowerbutts.com, rz@linux-m68k.org, geert@linux-m68k.org Subject: Re: [PATCH v2 2/3] ata: pata_falcon: add data_swab option to byte-swap disk data In-Reply-To: <20230818071405.28581-3-schmitzmic@gmail.com> Message-ID: <16f01be8-de2e-4fb2-50c3-95f030e740ac@linux-m68k.org> References: <20230818071405.28581-1-schmitzmic@gmail.com> <20230818071405.28581-3-schmitzmic@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Precedence: bulk List-ID: X-Mailing-List: linux-m68k@vger.kernel.org On Fri, 18 Aug 2023, Michael Schmitz wrote: > Some users of pata_falcon on Q40 have IDE disks in default > IDE little endian byte order, whereas legacy disks use > host-native big-endian byte order as on the Atari Falcon. > > Add module parameter 'data_swab' to allow connecting drives > with non-native data byte order. Drives selected by the > data_swap bit mask will have their user data byte-swapped to > host byte order, i.e. 'pata_falcon.data_swab=2' will byte-swap > all user data on drive B, leaving data on drive A in native > byte order. On Q40, drives on a second IDE interface may be > added to the bit mask as bits 2 and 3. > > Default setting is no byte swapping, i.e. compatibility with > the native Falcon or Q40 operating system disk format. > > Cc: William R Sowerbutts > Cc: Finn Thain > Cc: Geert Uytterhoeven > Signed-off-by: Michael Schmitz > > --- > > Changes since v1: > > Damien Le Moal: > - change patch title > - drop swap_data flag > > Finn Thain: > - drop allocation of ap->private struct, use field as bitmask > > Changes since RFC v4: > > Geert Uytterhoeven: > - don't shift static module parameter for drive 3/4 bitmask > - simplify bit mask calculation to always use pdev->id > > Finn Thain: > - correct bit numbers for drive 3/4 > > Changes since RFC v3: > > - split off this byte swap handling into separate patch > > - add hint regarding third and fourth drive on Q40 > > Finn Thain: > - rename module parameter to 'data_swab' to better reflect its use > > William Sowerbutts: > - correct IDE drive number used in data swap conditional > --- > drivers/ata/pata_falcon.c | 10 +++++++++- > 1 file changed, 9 insertions(+), 1 deletion(-) > > diff --git a/drivers/ata/pata_falcon.c b/drivers/ata/pata_falcon.c > index 346259e3bbc8..27443cb757de 100644 > --- a/drivers/ata/pata_falcon.c > +++ b/drivers/ata/pata_falcon.c > @@ -33,6 +33,11 @@ > #define DRV_NAME "pata_falcon" > #define DRV_VERSION "0.1.0" > > +static int pata_falcon_swap_mask; > + > +module_param_named(data_swab, pata_falcon_swap_mask, int, 0444); > +MODULE_PARM_DESC(data_swab, "Data byte swap enable/disable bitmap (0x1==drive1, 0x2==drive2, 0x4==drive3, 0x8==drive4, default==0)"); > + > static const struct scsi_host_template pata_falcon_sht = { > ATA_PIO_SHT(DRV_NAME), > }; > @@ -46,11 +51,12 @@ static unsigned int pata_falcon_data_xfer(struct ata_queued_cmd *qc, > void __iomem *data_addr = ap->ioaddr.data_addr; > unsigned int words = buflen >> 1; > struct scsi_cmnd *cmd = qc->scsicmd; > + int dev_id = dev->devno; Is that variable really needed? > bool swap = 1; > > if (dev->class == ATA_DEV_ATA && cmd && > !blk_rq_is_passthrough(scsi_cmd_to_rq(cmd))) > - swap = 0; > + swap = (uintptr_t)ap->private_data & BIT(dev_id); > > /* Transfer multiple of 2 bytes */ > if (rw == READ) { > @@ -199,6 +205,8 @@ static int __init pata_falcon_init_one(struct platform_device *pdev) > ap->ioaddr.altstatus_addr = ctl_base + io_offset; > ap->ioaddr.ctl_addr = ctl_base + io_offset; > > + ap->private_data = (void *)(uintptr_t)(pata_falcon_swap_mask >> (2 * pdev->id)); > + My compiler doesn't need that extra type cast in there... > irq_res = platform_get_resource(pdev, IORESOURCE_IRQ, 0); > if (irq_res && irq_res->start > 0) { > irq = irq_res->start; >