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Subject: Re: [PATCH v4 0/2] Exynos IOMMU: proper runtime PM support (use
 device dependencies)
To: Marek Szyprowski <m.szyprowski@samsung.com>, linux-pm@vger.kernel.org,
        linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org,
        linux-samsung-soc@vger.kernel.org
Cc: Joerg Roedel <joro@8bytes.org>, Inki Dae <inki.dae@samsung.com>,
        Kukjin Kim <kgene@kernel.org>,
        Krzysztof Kozlowski <k.kozlowski@samsung.com>,
        Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>,
        "Rafael J. Wysocki" <rjw@rjwysocki.net>,
        Mark Brown <broonie@kernel.org>,
        "Luis R. Rodriguez" <mcgrof@kernel.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Tomeu Vizoso <tomeu.vizoso@collabora.com>,
        Lukas Wunner <lukas@wunner.de>, Kevin Hilman <khilman@kernel.org>,
        Tobias Jakobi <tjakobi@math.uni-bielefeld.de>
References: <CGME20160929081238eucas1p1a064e5371ce549f860d6cff4bd43b557@eucas1p1.samsung.com>
 <1475136751-31340-1-git-send-email-m.szyprowski@samsung.com>
From: Tobias Jakobi <tjakobi@math.uni-bielefeld.de>
Message-ID: <57F581BD.3070208@math.uni-bielefeld.de>
Date: Thu, 6 Oct 2016 00:42:05 +0200
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Hello Marek,

I have applied the new version onto 4.8.0 but I'm seeing this Oops on
shutdown/reboot. However it only shows up with my non-debug config.


> [  897.046373] Internal error: Oops: 80000005 [#1] PREEMPT SMP ARM
> [  897.046652] Modules linked in: bridge stp llc bnep btrfs xor xor_neon zlib_inflate zlib_deflate raid6_pq s5p_mfc extcon_odroid_usbotg btusb btbcm btintel s5p_jpeg videobuf2_dma_contig v4l2_mem2mem videobuf2_memops videobuf2_v4l2 videobuf2_core
> [  897.068174] CPU: 2 PID: 9437 Comm: reboot Not tainted 4.8.0-vanilla+ #2
> [  897.074772] Hardware name: SAMSUNG EXYNOS (Flattened Device Tree)
> [  897.080848] task: eea02100 task.stack: cb488000
> [  897.085363] PC is at 0xb886c672
> [  897.088489] LR is at device_shutdown+0x134/0x1c0
> [  897.093087] pc : [<b886c672>]    lr : [<c0405b14>]    psr: 600a0073
> [  897.093087] sp : cb489e28  ip : 00000000  fp : cb489e4c
> [  897.104547] r10: 00000000  r9 : ee0cfe44  r8 : c0a39020
> [  897.109752] r7 : c0a6d774  r6 : ee0cfe10  r5 : ee08b810  r4 : ee0cfe1c
> [  897.116262] r3 : b886c673  r2 : 00000000  r1 : 00000002  r0 : ee0cfe10
> [  897.122773] Flags: nZCv  IRQs on  FIQs off  Mode SVC_32  ISA Thumb  Segment none
> [  897.130151] Control: 10c5387d  Table: 6a24404a  DAC: 00000051
> [  897.135879] Process reboot (pid: 9437, stack limit = 0xcb488218)
> [  897.141868] Stack: (0xcb489e28 to 0xcb48a000)
> [  897.146209] 9e20:                   00000000 00000000 01234567 c0a09d4c 00000010 c0a09a88
> [  897.154371] 9e40: cb489e5c cb489e50 c013eb5c c04059ec cb489e74 cb489e60 c013ec38 c013eb2c
> [  897.162530] 9e60: 01234567 c0a02448 cb489fa4 cb489e78 c013ef08 c013ec30 eb87ca80 00c0d000
> [  897.170698] 9e80: cb489ea4 cb489e90 c01c9660 c01c9434 ef026000 00000000 cb489eb4 cb489ea8
> [  897.178855] 9ea0: c01c977c c01c961c cb489ec4 cb489eb8 c01c9798 c01c9760 cb489f3c cb489ec8
> [  897.187014] 9ec0: c01eeaa4 c01c978c eb87ca80 00000000 ec421210 00c0d000 ed8af3c0 eefd5140
> [  897.195173] 9ee0: ee84a140 eea11e40 cb489f14 cb489ef8 c022bc58 c016cfa0 ed8afa80 ee665c38
> [  897.203333] 9f00: 00000000 eea11e50 cb489f24 cb489f18 c022be1c c022bc20 cb489f5c cb489f28
> [  897.211492] 9f20: c020ce88 c022bdfc 00000020 00000000 cb489f54 eea024f8 c0a39f7c 00000000
> [  897.219651] 9f40: eea02100 c0107ee4 cb488000 00000000 cb489f6c cb489f60 c020cf80 c020cd5c
> [  897.227810] 9f60: cb489f8c cb489f70 c013aa40 c06dd2dc cb488010 c0107ee4 cb489fb0 00040800
> [  897.235969] 9f80: 00000001 be966ce0 00bec008 00000058 c0107ee4 cb488000 00000000 cb489fa8
> [  897.244129] 9fa0: c0107d20 c013ee04 00000001 be966ce0 fee1dead 28121969 01234567 00000010
> [  897.252287] 9fc0: 00000001 be966ce0 00bec008 00000058 00000000 000230e4 00000000 00000000
> [  897.260447] 9fe0: 00023030 be966cc4 00010e9c b6f3f290 200a0050 fee1dead 00000000 00000000
> [  897.268603] Backtrace: 
> [  897.271033] [<c04059e0>] (device_shutdown) from [<c013eb5c>] (kernel_restart_prepare+0x3c/0x40)
> [  897.279715]  r9:c0a09a88 r8:00000010 r7:c0a09d4c r6:01234567 r5:00000000 r4:00000000
> [  897.287439] [<c013eb20>] (kernel_restart_prepare) from [<c013ec38>] (kernel_restart+0x14/0x58)
> [  897.296036] [<c013ec24>] (kernel_restart) from [<c013ef08>] (SyS_reboot+0x110/0x1f8)
> [  897.303757]  r4:c0a02448 r3:01234567
> [  897.307314] [<c013edf8>] (SyS_reboot) from [<c0107d20>] (ret_fast_syscall+0x0/0x3c)
> [  897.314955]  r9:cb488000 r8:c0107ee4 r7:00000058 r6:00bec008 r5:be966ce0 r4:00000001
> [  897.322680] Code: bad PC value
> [  897.325940] ---[ end trace 861fd282a7bdc01e ]---


The corresponding config:
https://github.com/tobiasjakobi/odroid-environment/blob/master/sourcecode/system/vanilla-4.8.conf


With best wishes,
Tobias




Marek Szyprowski wrote:
> Hello,
> 
> This patch series finally implements proper runtime PM support in Exynos
> IOMMU driver. This has been achieved by using recently introduce device
> links, which lets SYSMMU controller's runtime PM to follow master's device
> runtime PM state (the device which actually performs DMA transaction).
> The main idea behind this solution is an observation that any DMA activity
> from master device can be done only when master device is active, thus when
> master device is suspended SYSMMU controller device can also be suspended.
> 
> This patchset solves the situation that power domains are always enabled,
> because all SYSMMU controllers (which belongs to those domains) are
> permanently active (because existing driver was simplified and kept
> SYSMMU device active all the time after initialization).
> 
> Patch requires fourth version of Rafeal's "Functional dependencies
> between devices" patchset, which is available here:
> https://www.mail-archive.com/linux-kernel@vger.kernel.org/msg1241473.html
> 
> If one wants to test this patchset, I've provided a branch with all needed
> patches (some fixes for Exynos4 FIMC-IS driver are needed):
> https://git.linaro.org/people/marek.szyprowski/linux-srpol.git v4.8-iommu-pm-v4
> 
> Patches are based on vanilla v4.8-rc8 kernel with Rafael's device
> dependencies v4 patchset applied.
> 
> Best regards
> Marek Szyprowski
> Samsung R&D Institute Poland
> 
> 
> Changelog:
> v4:
> - rebased on top of v4 of device dependencies/links patchset, what resolved
>   system hang on reboot
> 
> v3: http://www.spinics.net/lists/linux-samsung-soc/msg55256.html
> - rebased on top of latest device dependencies/links patchset
> - added proper locking between runtime pm, iommu_attach/detach and sysmmu
>   enable/disable(added per iommu owner device's rpm lock)
> 
> v2: http://www.spinics.net/lists/arm-kernel/msg512082.html
> - replaced PM notifiers with generic device dependencies/links developped
>   by Rafael J. Wysocki
> 
> v1: http://www.spinics.net/lists/arm-kernel/msg509600.html
> - initial version
> 
> 
> Patch summary:
> 
> Marek Szyprowski (2):
>   iommu/exynos: Remove excessive, useless debug
>   iommu/exynos: Add proper runtime pm support
> 
>  drivers/iommu/exynos-iommu.c | 228 ++++++++++++++++++-------------------------
>  1 file changed, 94 insertions(+), 134 deletions(-)
>