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From:   Peter Geis <pgwipeout@gmail.com>
Date:   Mon, 12 Apr 2021 16:49:59 -0400
Message-ID: <CAMdYzYrQ5f-mv_VmTq_CRf9tR=j3mwRpKHNLmPFgCF9whsGFRw@mail.gmail.com>
Subject: [RFC] ITS fails to allocate on rk3568/rk3566
To:     Thomas Gleixner <tglx@linutronix.de>, Marc Zyngier <maz@kernel.org>
Cc:     "open list:ARM/Rockchip SoC..." <linux-rockchip@lists.infradead.org>,
        linux-kernel@vger.kernel.org
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Good Afternoon,

I am assisting with early bringup of the rk3566 based quartz64
development board for mainline linux.
I've encountered a few issues with allocating ITS on their version of
the GIC-V3.
The first issue is the ITS controller can only use 32bit addresses.
This leads to the following error:
[    0.000000] NR_IRQS: 64, nr_irqs: 64, preallocated irqs: 0
[    0.000000] GICv3: GIC: Using split EOI/Deactivate mode
[    0.000000] GICv3: 320 SPIs implemented
[    0.000000] GICv3: 0 Extended SPIs implemented
[    0.000000] GICv3: Distributor has no Range Selector support
[    0.000000] Root IRQ handler: gic_handle_irq
[    0.000000] GICv3: 16 PPIs implemented
[    0.000000] GICv3: CPU0: found redistributor 0 region 0:0x00000000fd460000
[    0.000000] ITS [mem 0xfd440000-0xfd45ffff]
[    0.000000] ITS@0x00000000fd440000: Devices doesn't stick:
f907000100190600 f907000000190600
[    0.000000] ITS@0x00000000fd440000: failed probing (-6)
[    0.000000] ITS: No ITS available, not enabling LPIs

Downstream fixed this by adding the GFP_DMA32 flag to the memory allocations.
They also force clear the GITS_BASER_SHAREABILITY_MASK.
Unfortunately while this allowed ITS to allocate on downstream, as
soon as MSIs attempted to use it all interrupts would time out.

On upstream, we observe this during allocation:
[    0.000000] ITS [mem 0xfd440000-0xfd45ffff]
[    0.000000] ITS@0x00000000fd440000: allocated 8192 Devices @3810000
(indirect, esz 8, psz 64K, shr 1)
[    0.000000] ITS@0x00000000fd440000: allocated 32768 Interrupt
Collections @3820000 (flat, esz 2, psz 64K, shr 1)
[    0.000000] GICv3: using LPI property table @0x0000000003830000
[    0.000000] GICv3: CPU0: using allocated LPI pending table
@0x0000000003840000
[    0.000000] ITS queue timeout (64 1)
[    0.000000] ITS cmd its_build_mapc_cmd failed
[    0.000000] ITS queue timeout (96 1)
[    0.000000] ITS cmd its_build_invall_cmd failed
<snip>
[    0.150282] Platform MSI: interrupt-controller@fd440000 domain created
[    0.152409] PCI/MSI:
/interrupt-controller@fd400000/interrupt-controller@fd440000 domain
created
[    0.156158] EFI services will not be available.
[    0.161168] smp: Bringing up secondary CPUs ...
[    0.170252] Detected VIPT I-cache on CPU1
[    0.170325] GICv3: CPU1: found redistributor 100 region 0:0x00000000fd480000
[    0.170356] GICv3: GIC_READ_PMR old_pmr=0xf0
[    0.170371] GICv3: GIC_READ_PMR new_pmr=0x0
[    0.170393] GICv3: CPU1: using allocated LPI pending table
@0x0000000003850000
[    1.686709] ITS queue timeout (160 1)
[    1.686733] ITS cmd its_build_mapc_cmd failed
[    3.202979] ITS queue timeout (192 1)
[    3.202999] ITS cmd its_build_invall_cmd failed
[    3.203157] CPU1: Booted secondary processor 0x0000000100 [0x412fd050]
[    3.208303] Callback from call_rcu_tasks_rude() invoked.
[    3.228487] Detected VIPT I-cache on CPU2
[    3.228559] GICv3: CPU2: found redistributor 200 region 0:0x00000000fd4a0000
[    3.228590] GICv3: GIC_READ_PMR old_pmr=0xf0
[    3.228606] GICv3: GIC_READ_PMR new_pmr=0x0
[    3.228630] GICv3: CPU2: using allocated LPI pending table
@0x0000000003860000
[    4.744675] ITS queue timeout (256 1)
[    4.744698] ITS cmd its_build_mapc_cmd failed
[    6.260797] ITS queue timeout (288 1)
[    6.260816] ITS cmd its_build_invall_cmd failed
[    6.260948] CPU2: Booted secondary processor 0x0000000200 [0x412fd050]
[    6.269204] Callback from call_rcu_tasks() invoked.
[    6.278358] Detected VIPT I-cache on CPU3
[    6.278430] GICv3: CPU3: found redistributor 300 region 0:0x00000000fd4c0000
[    6.278460] GICv3: GIC_READ_PMR old_pmr=0xf0
[    6.278476] GICv3: GIC_READ_PMR new_pmr=0x0
[    6.278501] GICv3: CPU3: using allocated LPI pending table
@0x0000000003870000
[    7.794367] ITS queue timeout (352 1)
[    7.794390] ITS cmd its_build_mapc_cmd failed
[    9.310219] ITS queue timeout (384 1)
[    9.310237] ITS cmd its_build_invall_cmd failed
[    9.310368] CPU3: Booted secondary processor 0x0000000300 [0x412fd050]
[    9.311925] smp: Brought up 1 node, 4 CPUs
[    9.318831] SMP: Total of 4 processors activated.

Also, when MSIs activate the same timeouts seen downstream happen:
[   13.884698] pci 0000:00:00.0: PCI bridge to [bus 01-ff]
[   13.886476] pcieport 0000:00:00.0: of_irq_parse_pci: failed with rc=-22
[   13.887466] pcieport 0000:00:00.0: assign IRQ: got 0
[   15.414727] ITS queue timeout (416 1)
[   15.415476] ITS cmd its_build_mapd_cmd failed
[   16.957519] ITS queue timeout (480 1)
[   16.958040] ITS cmd its_build_mapti_cmd failed
[   18.482251] ITS queue timeout (544 1)
[   18.482762] ITS cmd its_build_mapti_cmd failed
<snip>
[   70.267783] ITS queue timeout (2656 1)
[   70.268363] ITS cmd its_build_inv_cmd failed
[   70.269782] pcieport 0000:00:00.0: PME: Signaling with IRQ 64

Any assistance you can provide would be greatly appreciated.

Very Respectfully,
Peter Geis