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

[Sumit Garg]

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

-Sumit

>  include/linux/soc/ti/ti_sci_protocol.h            |   9 ++
>  21 files changed, 721 insertions(+), 18 deletions(-)
> ---
> base-commit: a517796cfa5d8f4ca2f0c11c78c24a08a102c047
> change-id: 20250306-topic-am62-ioddr-v2025-04-rc1-0b3a0ffe92b1
>
> Best regards,
> --
> Markus Schneider-Pargmann <msp at baylibre.com>
>