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    SubjectRe: [PATCH AUTOSEL 5.5 219/542] ARM: OMAP2+: use separate IOMMU pdata to fix DRA7 IPU1 boot
    On Fri, Feb 14, 2020 at 12:34:58PM -0600, Suman Anna wrote:
    >Hi Sasha,
    >
    >On 2/14/20 9:43 AM, Sasha Levin wrote:
    >> From: Suman Anna <s-anna@ti.com>
    >>
    >> [ Upstream commit 4601832f40501efc3c2fd264a5a69bd1ac17d520 ]
    >>
    >> The IPU1 MMU has been using common IOMMU pdata quirks defined and
    >> used by all IPU IOMMU devices on OMAP4 and beyond. Separate out the
    >> pdata for IPU1 MMU with the additional .set_pwrdm_constraint ops
    >> plugged in, so that the IPU1 power domain can be restricted to ON
    >> state during the boot and active period of the IPU1 remote processor.
    >> This eliminates the pre-conditions for the IPU1 boot issue as
    >> described in commit afe518400bdb ("iommu/omap: fix boot issue on
    >> remoteprocs with AMMU/Unicache").
    >>
    >> NOTE:
    >> 1. RET is not a valid target power domain state on DRA7 platforms,
    >> and IPU power domain is normally programmed for OFF. The IPU1
    >> still fails to boot though, and an unclearable l3_noc error is
    >> thrown currently on 4.14 kernel without this fix. This behavior
    >> is slightly different from previous 4.9 LTS kernel.
    >> 2. The fix is currently applied only to IPU1 on DRA7xx SoC, as the
    >> other affected processors on OMAP4/OMAP5/DRA7 are in domains
    >> that are not entering RET. IPU2 on DRA7 is in CORE power domain
    >> which is only programmed for ON power state. The fix can be easily
    >> scaled if these domains do hit RET in the future.
    >> 3. The issue was not seen on current DRA7 platforms if any of the
    >> DSP remote processors were booted and using one of the GPTimers
    >> 5, 6, 7 or 8 on previous 4.9 LTS kernel. This was due to the
    >> errata fix for i874 implemented in commit 1cbabcb9807e ("ARM:
    >> DRA7: clockdomain: Implement timer workaround for errata i874")
    >> which keeps the IPU1 power domain from entering RET when the
    >> timers are active. But the timer workaround did not make any
    >> difference on 4.14 kernel, and an l3_noc error was seen still
    >> without this fix.
    >>
    >> Signed-off-by: Suman Anna <s-anna@ti.com>
    >> Signed-off-by: Tony Lindgren <tony@atomide.com>
    >> Signed-off-by: Sasha Levin <sashal@kernel.org>
    >
    >And drop this one as well, since mainline doesn't yet boot
    >the processors, so this is not needed for stable queue.

    Now dropped, thank you.

    --
    Thanks,
    Sasha

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