From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 49B3C7C for ; Mon, 5 Dec 2022 14:05:03 +0000 (UTC) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 34A9F23A; Mon, 5 Dec 2022 06:05:09 -0800 (PST) Received: from [10.57.71.118] (unknown [10.57.71.118]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 222003F71A; Mon, 5 Dec 2022 06:05:00 -0800 (PST) Message-ID: <71dbee25-8b93-a306-d7a1-abc17d1d7273@arm.com> Date: Mon, 5 Dec 2022 14:04:57 +0000 Precedence: bulk X-Mailing-List: asahi@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; rv:102.0) Gecko/20100101 Thunderbird/102.5.0 Subject: Re: [PATCH] iommu: dart: Add suspend/resume support Content-Language: en-GB To: Hector Martin , Joerg Roedel , Will Deacon Cc: Sven Peter , Alyssa Rosenzweig , asahi@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org References: <20221205100907.10230-1-marcan@marcan.st> From: Robin Murphy In-Reply-To: <20221205100907.10230-1-marcan@marcan.st> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 2022-12-05 10:09, Hector Martin wrote: > We need to save/restore the TCR/TTBR registers, since they are lost > on power gate. > > Signed-off-by: Hector Martin > --- > drivers/iommu/apple-dart.c | 50 ++++++++++++++++++++++++++++++++++++++ > 1 file changed, 50 insertions(+) > > diff --git a/drivers/iommu/apple-dart.c b/drivers/iommu/apple-dart.c > index 4f4a323be0d0..ed524765ad87 100644 > --- a/drivers/iommu/apple-dart.c > +++ b/drivers/iommu/apple-dart.c > @@ -121,6 +121,9 @@ struct apple_dart { > > struct iommu_group *sid2group[DART_MAX_STREAMS]; > struct iommu_device iommu; > + > + u32 save_tcr[DART_MAX_STREAMS]; > + u32 save_ttbr[DART_MAX_STREAMS][DART_MAX_TTBR]; > }; > > /* > @@ -932,6 +935,50 @@ static const struct apple_dart_hw apple_dart_hw_t6000 = { > .fmt = APPLE_DART2, > }; > > +#ifdef CONFIG_PM_SLEEP Between DEFINE_SIMPLE_DEV_PM_OPS() and pm_sleep_ptr(), I think we should be able to allow full coverage without any explicit #ifdefs or other annotations now. Cheers, Robin. > +static int apple_dart_suspend(struct device *dev) > +{ > + struct apple_dart *dart = dev_get_drvdata(dev); > + unsigned int sid, idx; > + > + for (sid = 0; sid < DART_MAX_STREAMS; sid++) { > + dart->save_tcr[sid] = readl_relaxed(dart->regs + DART_TCR(sid)); > + for (idx = 0; idx < DART_MAX_TTBR; idx++) > + dart->save_ttbr[sid][idx] = > + readl_relaxed(dart->regs + DART_TTBR(sid, idx)); > + } > + > + return 0; > +} > + > +static int apple_dart_resume(struct device *dev) > +{ > + struct apple_dart *dart = dev_get_drvdata(dev); > + unsigned int sid, idx; > + int ret; > + > + ret = apple_dart_hw_reset(dart); > + if (ret) { > + dev_err(dev, "Failed to reset DART on resume\n"); > + return ret; > + } > + > + for (sid = 0; sid < DART_MAX_STREAMS; sid++) { > + for (idx = 0; idx < DART_MAX_TTBR; idx++) > + writel_relaxed(dart->save_ttbr[sid][idx], > + dart->regs + DART_TTBR(sid, idx)); > + writel_relaxed(dart->save_tcr[sid], dart->regs + DART_TCR(sid)); > + } > + > + return 0; > +} > + > +static const struct dev_pm_ops apple_dart_pm_ops = { > + .suspend = apple_dart_suspend, > + .resume = apple_dart_resume, > +}; > +#endif > + > static const struct of_device_id apple_dart_of_match[] = { > { .compatible = "apple,t8103-dart", .data = &apple_dart_hw_t8103 }, > { .compatible = "apple,t6000-dart", .data = &apple_dart_hw_t6000 }, > @@ -944,6 +991,9 @@ static struct platform_driver apple_dart_driver = { > .name = "apple-dart", > .of_match_table = apple_dart_of_match, > .suppress_bind_attrs = true, > +#ifdef CONFIG_PM_SLEEP > + .pm = &apple_dart_pm_ops, > +#endif > }, > .probe = apple_dart_probe, > .remove = apple_dart_remove,