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 0AE96C433FE for ; Mon, 7 Nov 2022 18:09:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233055AbiKGSJZ (ORCPT ); Mon, 7 Nov 2022 13:09:25 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51338 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232796AbiKGSJD (ORCPT ); Mon, 7 Nov 2022 13:09:03 -0500 Received: from mail-ed1-x534.google.com (mail-ed1-x534.google.com [IPv6:2a00:1450:4864:20::534]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B4F2DBE1 for ; Mon, 7 Nov 2022 10:05:36 -0800 (PST) Received: by mail-ed1-x534.google.com with SMTP id x2so18891686edd.2 for ; Mon, 07 Nov 2022 10:05:36 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=VCTpqEx+nj1n6HjmRbfujsCzReaOepaCfo3WlWBlSOs=; b=kkw8H1QERm0GF5D+iS4KT6fZ4SYYp6uvTjhGEoGPgwq4dVWvWQjaCel2y3WVJlaOaE e5RStAF8t1Pu63/2phYMxZ3eMnlV8avzvgW8eaZg0kjlNhuonZsrQ+N3F29oFWWrbQJa 0XVweEG5LvZrQIkVPfXx6PQxtjzmogkRZ8eqbG/jSCdy2MHJMkMLcPkpBEt1otOhJYmn /5Sc1TtwiGnxrxCE2p+iu+jd3zCXnPCD0XO8jVbQI6zSVlLPWgVWZ53XA5kXJlQFadqg et0hOf+R8C8fwCn5J8LpjKtYNuZiFG6vjBLWY1Oo5dx42Q4PDYm3/bFeE+WuqhN6s16z avfQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=VCTpqEx+nj1n6HjmRbfujsCzReaOepaCfo3WlWBlSOs=; b=t0DhpKys9h+VGkEFVZFE8rdl2jO65MAi0RIFs927vsAN2KWKxIaH1359+cknyOgKqK ymOF2TF9f7T3A1rZXKi/rwtjzAdMdVIVnEJ8rN5JhucJ7mbixP3FtVaRd1aNOzmZRGwW 4E/tCViJf+sHh6GczNnY1xJ5NqnveGOl7leOQVvdKWlBUDzoMi5ZupCKMdZkvqWVxcri 4EzW7gnvblDse5nqDVXC0aX5822YXpiEZ9C0rnjwIduopJWPvj6x850l+Vrc73aTBhbL XbMjehjIhwHKDCIypf1rjKY39XXyY82zb6hm5aPgm0qWlptV8NcI5SkTC+SxY08bOPoA HOOg== X-Gm-Message-State: ACrzQf3ee83MuxlY+9nHU9hhgOp/5zeXwd344I+udQ2aNG00D2vaTGp+ yNPbuQ4OmqvP4fBGS71ZaEw= X-Google-Smtp-Source: AMsMyM6Goj84logVrQ5XP20UoYPJnj8X72vsGoAAviPjLBcIzvX+wqD4eLNfV4AQDTIEyo+FSyuFaQ== X-Received: by 2002:a05:6402:1d4f:b0:461:d2ed:788c with SMTP id dz15-20020a0564021d4f00b00461d2ed788cmr51595245edb.418.1667844335245; Mon, 07 Nov 2022 10:05:35 -0800 (PST) Received: from kista.localnet (82-149-19-102.dynamic.telemach.net. [82.149.19.102]) by smtp.gmail.com with ESMTPSA id p20-20020a17090653d400b007adf2e4c6f7sm3694732ejo.195.2022.11.07.10.05.34 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 07 Nov 2022 10:05:34 -0800 (PST) From: Jernej =?utf-8?B?xaBrcmFiZWM=?= To: Samuel Holland , Andre Przywara Cc: Chen-Yu Tsai , linux-arm-kernel@lists.infradead.org, Ivaylo Dimitrov , linux-kernel@vger.kernel.org, linux-sunxi@lists.linux.dev Subject: Re: Re: [PATCH v2 2/2] bus: sunxi-rsb: Support atomic transfers Date: Mon, 07 Nov 2022 19:05:33 +0100 Message-ID: <1929426.usQuhbGJ8B@kista> In-Reply-To: <20221107112949.21f52e50@donnerap.cambridge.arm.com> References: <20221107052201.65477-1-samuel@sholland.org> <20221107052201.65477-3-samuel@sholland.org> <20221107112949.21f52e50@donnerap.cambridge.arm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Dne ponedeljek, 07. november 2022 ob 12:30:29 CET je Andre Przywara napisal(a): > On Sun, 6 Nov 2022 23:22:00 -0600 > Samuel Holland wrote: > > Hi, > > > When communicating with a PMIC during system poweroff (pm_power_off()), > > IRQs are disabled and we are in a RCU read-side critical section, so we > > cannot use wait_for_completion_io_timeout(). Instead, poll the status > > register for transfer completion. > > > > Fixes: d787dcdb9c8f ("bus: sunxi-rsb: Add driver for Allwinner Reduced > > Serial Bus") Signed-off-by: Samuel Holland > > --- > > > > Changes in v2: > > - Add Fixes tag to patch 2 > > - Only check for specific status bits when polling > > > > drivers/bus/sunxi-rsb.c | 27 ++++++++++++++++++++------- > > 1 file changed, 20 insertions(+), 7 deletions(-) > > > > diff --git a/drivers/bus/sunxi-rsb.c b/drivers/bus/sunxi-rsb.c > > index 17343cd75338..012e82f9b7b0 100644 > > --- a/drivers/bus/sunxi-rsb.c > > +++ b/drivers/bus/sunxi-rsb.c > > @@ -267,6 +267,9 @@ EXPORT_SYMBOL_GPL(sunxi_rsb_driver_register); > > > > /* common code that starts a transfer */ > > static int _sunxi_rsb_run_xfer(struct sunxi_rsb *rsb) > > { > > > > + u32 int_mask, status; > > + bool timeout; > > + > > > > if (readl(rsb->regs + RSB_CTRL) & RSB_CTRL_START_TRANS) { > > > > dev_dbg(rsb->dev, "RSB transfer still in progress\n"); > > return -EBUSY; > > > > @@ -274,13 +277,23 @@ static int _sunxi_rsb_run_xfer(struct sunxi_rsb > > *rsb) > > > > reinit_completion(&rsb->complete); > > > > - writel(RSB_INTS_LOAD_BSY | RSB_INTS_TRANS_ERR | RSB_INTS_TRANS_OVER, > > + int_mask = RSB_INTS_LOAD_BSY | RSB_INTS_TRANS_ERR | RSB_INTS_TRANS_OVER; > > + writel(int_mask, > > > > rsb->regs + RSB_INTE); > > > > writel(RSB_CTRL_START_TRANS | RSB_CTRL_GLOBAL_INT_ENB, > > > > rsb->regs + RSB_CTRL); > > > > - if (!wait_for_completion_io_timeout(&rsb->complete, > > - msecs_to_jiffies(100))) { > > + if (irqs_disabled()) { > > + timeout = readl_poll_timeout_atomic(rsb->regs + RSB_INTS, > > + status, (status & int_mask), > > + 10, 100000); > > So if I understand correctly, this mimics the operation of > sunxi_rsb_irq(), just replacing rsb->status with status. > But wouldn't that also mean that we need to clear the interrupt bits in > INTS, since we are about to handle them below? Yes, I pointed out that in review of v1. Best regards, Jernej > > It probably doesn't matter in practise, since we call this during power > down only, but looks like more robust to do, from a driver's perspective. > > Cheers, > Andre > > > + } else { > > + timeout = !wait_for_completion_io_timeout(&rsb- >complete, > > + msecs_to_jiffies(100)); > > + status = rsb->status; > > + } > > + > > + if (timeout) { > > > > dev_dbg(rsb->dev, "RSB timeout\n"); > > > > /* abort the transfer */ > > > > @@ -292,18 +305,18 @@ static int _sunxi_rsb_run_xfer(struct sunxi_rsb > > *rsb) > > > > return -ETIMEDOUT; > > > > } > > > > - if (rsb->status & RSB_INTS_LOAD_BSY) { > > + if (status & RSB_INTS_LOAD_BSY) { > > > > dev_dbg(rsb->dev, "RSB busy\n"); > > return -EBUSY; > > > > } > > > > - if (rsb->status & RSB_INTS_TRANS_ERR) { > > - if (rsb->status & RSB_INTS_TRANS_ERR_ACK) { > > + if (status & RSB_INTS_TRANS_ERR) { > > + if (status & RSB_INTS_TRANS_ERR_ACK) { > > > > dev_dbg(rsb->dev, "RSB slave nack\n"); > > return -EINVAL; > > > > } > > > > - if (rsb->status & RSB_INTS_TRANS_ERR_DATA) { > > + if (status & RSB_INTS_TRANS_ERR_DATA) { > > > > dev_dbg(rsb->dev, "RSB transfer data error\n"); > > return -EIO; > > > > }