Messages in this thread | | | Date | Thu, 20 Feb 2020 11:46:28 -0500 | From | Sasha Levin <> | Subject | Re: [PATCH AUTOSEL 5.5 218/542] ARM: OMAP2+: Add workaround for DRA7 DSP MStandby errata i879 |
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On Fri, Feb 14, 2020 at 12:34:19PM -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 2f14101a1d760db72393910d481fbf7768c44530 ] >> >> Errata Title: >> i879: DSP MStandby requires CD_EMU in SW_WKUP >> >> Description: >> The DSP requires the internal emulation clock to be actively toggling >> in order to successfully enter a low power mode via execution of the >> IDLE instruction and PRCM MStandby/Idle handshake. This assumes that >> other prerequisites and software sequence are followed. >> >> Workaround: >> The emulation clock to the DSP is free-running anytime CCS is connected >> via JTAG debugger to the DSP subsystem or when the CD_EMU clock domain >> is set in SW_WKUP mode. The CD_EMU domain can be set in SW_WKUP mode >> via the CM_EMU_CLKSTCTRL [1:0]CLKTRCTRL field. >> >> Implementation: >> This patch implements this workaround by denying the HW_AUTO mode >> for the EMU clockdomain during the power-up of any DSP processor >> and re-enabling the HW_AUTO mode during the shutdown of the last >> DSP processor (actually done during the enabling and disabling of >> the respective DSP MDMA MMUs). Reference counting has to be used to >> manage the independent sequencing between the multiple DSP processors. >> >> This switching is done at runtime rather than a static clockdomain >> flags value to meet the target power domain state for the EMU power >> domain during suspend. >> >> Note that the DSP MStandby behavior is not consistent across all >> boards prior to this fix. Please see commit 45f871eec6c0 ("ARM: >> OMAP2+: Extend DRA7 IPU1 MMU pdata quirks to DSP MDMA MMUs") for >> details. >> >> 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> > >You can drop this from the 5.5-stable queue. 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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