[PATCH 00/19] am62: IO+DDR resume support

Tue Mar 11 15:35:51 CET 2025

Hi Sumit,

On Tue, Mar 11, 2025 at 04:19:58PM +0530, Sumit Garg wrote:
> Hi Markus,
> 
> On Tue, 11 Mar 2025 at 16:02, Markus Schneider-Pargmann
> <msp at baylibre.com> wrote:
> >
> > Hi,
> >
> > this series introduces support to resume from IO+DDR. IO+DDR is a low
> > power mode of am62a and am62p in which nearly everything is powered off
> > except DDR which is in self-refresh and a few pins which detect
> > activity and can wakeup the system again.
> >
> > On resume uboot SPL is loaded and checks if this is a IO+DDR resume. If
> > it is, the DDR initialization sequence in k3-ddrss differs slightly as
> > it has to get the DDR out of the self-refresh.
> >
> > Afterwards a specific address determined from DT is used to get the
> > metadata that stores relevant context addresses. The context is restored
> > using the tisci message TI_SCI_MSG_MIN_CONTEXT_RESTORE. At the end all
> > further initializations are skipped and uboot SPL directly jumps into
> > the DM resume address which takes care of the rest.
> >
> > The devicetree R5F related patches were picked up from the mailinglist
> > and are required to find the correct address of the metadata.
> >
> > k3-ddrss is using absolute register accesses at the moment. I am trying
> > to submit syscon DT patches upstream to access these through syscon,
> > unfortunately there is ongoing discussion regarding syscon.
> >
> > I tested this on am62a.
> >
> > Best,
> > Markus
> >
> > To: Tom Rini <trini at konsulko.com>
> > To: Vignesh Raghavendra <vigneshr at ti.com>
> > To: Bryan Brattlof <bb at ti.com>
> > To: Sumit Garg <sumit.garg at linaro.org>
> > Cc: u-boot at lists.denx.de
> >
> > Cc: Vishal Mahaveer <vishalm at ti.com>
> > Cc: Kevin Hilman <khilman at baylibre.com>
> > Cc: Dhruva Gole <d-gole at ti.com>
> > Cc: Sebin Francis <sebin.francis at ti.com>
> > Cc: Kendall Willis <k-willis at ti.com>
> > Cc: Akashdeep Kaur <a-kaur at ti.com>
> >
> > Signed-off-by: Markus Schneider-Pargmann <msp at baylibre.com>
> > ---
> > Devarsh Thakkar (3):
> >       arm64: dts: ti: k3-am62a-wakeup: Add R5F device node
> >       arm64: dts: ti: k3-am62a7-sk: Enable IPC with remote processors
> >       arm64: dts: ti: k3-am62p5-sk: Enable IPC with remote processors
> >
> > Hari Nagalla (2):
> >       arm64: dts: ti: k3-am62a-mcu: Add R5F remote proc node
> >       arm64: dts: ti: k3-am62x-sk-common: Enable IPC with remote processors
> >
> > Jai Luthra (1):
> >       arm64: dts: ti: k3-am62a-main: Add C7xv device node
> >
> > Markus Schneider-Pargmann (13):
> >       arm: mach-k3: Remove CANUART IO isolation
> >       arm: mach-k3: Kconfig: Add symbols for IO+DDR Low Power Mode
> >       ram: k3-ddrss: Add support for DDR in self-refresh
> >       firmware: ti_sci: Add TI_SCI_MSG_MIN_CONTEXT_RESTORE
> >       arm: mach-k3: common: Add CANUART wakeup check helpers
> >       arm: mach-k3: common: Add lpm_resume_from_ddr
> >       arm: mach-k3: common: Helper for LPM meta data address from DT
> >       arm: mach-k3: am62a7_init: Resume on LPM exit
> >       arm: mach-k3: am62p5_init: Resume on LPM exit
> >       arm: dts: k3-am62a: Add r5 device nodes
> >       arm: dts: k3-am62p: Add r5 device nodes
> >       configs: am62ax_evm_r5: Enable IODDR resume support
> >       configs: am62p_evm_r5_defconfig: Enable IODDR resume support
> >
> >  arch/arm/dts/k3-am62a7-sk-u-boot.dtsi             |  16 +++
> >  arch/arm/dts/k3-am62p5-sk-u-boot.dtsi             |  20 +++
> >  arch/arm/mach-k3/Kconfig                          |   9 ++
> >  arch/arm/mach-k3/am62ax/am62a7_init.c             |  11 ++
> >  arch/arm/mach-k3/am62px/am62p5_init.c             |  12 ++
> >  arch/arm/mach-k3/am62x/am625_init.c               |   2 +
> >  arch/arm/mach-k3/common.c                         | 162 +++++++++++++++++++++
> >  arch/arm/mach-k3/common.h                         |   4 +
> >  arch/arm/mach-k3/include/mach/hardware.h          |  32 +++++
> >  configs/am62ax_evm_r5_defconfig                   |   1 +
> >  configs/am62px_evm_r5_defconfig                   |   1 +
> >  drivers/firmware/ti_sci.c                         |  38 +++++
> >  drivers/firmware/ti_sci.h                         |  14 ++
> >  drivers/ram/k3-ddrss/k3-ddrss.c                   | 165 ++++++++++++++++++++++
> 
> >  dts/upstream/src/arm64/ti/k3-am62a-main.dtsi      |  12 ++
> >  dts/upstream/src/arm64/ti/k3-am62a-mcu.dtsi       |  25 ++++
> >  dts/upstream/src/arm64/ti/k3-am62a-wakeup.dtsi    |  25 ++++
> >  dts/upstream/src/arm64/ti/k3-am62a7-sk.dts        |  96 ++++++++++++-
> >  dts/upstream/src/arm64/ti/k3-am62p5-sk.dts        |  50 ++++++-
> >  dts/upstream/src/arm64/ti/k3-am62x-sk-common.dtsi |  35 ++++-
> 
> The dts/upstream is a git subtree and is rather a snapshot of upstream
> devicetree-rebasing repo. It's not allowed to directly patch it but
> rather we need to resync or cherry-pick patches from upstream [1].
> 
> So rather than picking patches from ML, you should wait for them to
> land in the Linux kernel for a cherry-pick to work. Or otherwise you
> can choose to rely on *-u-boot.dtsi for the time being.
> 
> [1] https://docs.u-boot.org/en/latest/develop/devicetree/control.html#resyncing-with-devicetree-rebasing

Thanks for the link, I didn't notice the handy scripts. Yes these are
currently only mailinglist patches, but hopefully soon in the kernel so
I can replace them in this series. I sent the series anyways to get some
feedback already so I can work on the other aspects that need fixing in
these patches.

Thank you!

Best
Markus
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