[PATCH v7 00/13] am62: IO+DDR resume support

Wed Dec 10 15:08:54 CET 2025

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.

Afterward 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.

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

Signed-off-by: Markus Schneider-Pargmann (TI.com) <msp at baylibre.com>
---
Changes in v7:
- Removed parent nodes bootph-pre-ram properties as not necessary
  anymore.
- Added missing new line in
    arm: mach-k3: common: Helper for LPM meta data address from DT
- Split off LPM specific ddr code into its own file k3-ddrss-lpm
- Rename lpm_ops->restore_context to lpm_ops->min_context_restore
- Pulled patch to add wakeup check helpers before the IO isolation
  removal to remove later cleanup of
  wkup_ctrl_remove_can_io_isolation_if_set()
- Some reviewed-bys and tested-bys removed due to changes in the
  patches
- Link to v6: https://lore.kernel.org/r/20251120-topic-am62-ioddr-v2025-04-rc1-v6-0-6dd99a7271bb@baylibre.com

Changes in v6:
- Add comment for last part of removing can io isolation
- Only mention a single kconfig symbol in the commit message
- Add defines for timeouts in k3-ddrss
- Link to v5: https://lore.kernel.org/r/20251110-topic-am62-ioddr-v2025-04-rc1-v5-0-980ee0036c26@baylibre.com

Changes in v5:
- Fixed compile warnings
- Link to v4: https://lore.kernel.org/r/20251030-topic-am62-ioddr-v2025-04-rc1-v4-0-4cef18af0226@baylibre.com

Changes in v4:
- Copy lpm_meta_data into the stack to be able to debug unstable memory
  issues
- Add missing comments about ctx_lo and ctx_hi
- Use absolute addresses for k3-ddrss CANUART_WAKE_STAT1 and
  CANUART_WAKE_OFF_MODE_STAT to avoid using addresses outside of the
  range given in the devicetree
- Remove the cherry picked devicetree patches as they are already
  included now
- In lpm_resume_from_ddr() print upper and lower 32bit of the meta data
  values separately.
- Link to v3: https://lore.kernel.org/r/20250623-topic-am62-ioddr-v2025-04-rc1-v3-0-a4da322c16af@baylibre.com

Changes in v3:
- Use wait_for_bit helpers in k3-ddrss where possible and add panic
  messages for easier debugging
- Link to v2: https://lore.kernel.org/r/20250613-topic-am62-ioddr-v2025-04-rc1-v2-0-3d233aaea355@baylibre.com

Changes in v2:
- Remove 'default n' from K3_IODDR
- Pick devicetree patches from upstream instead of mailinglist
- Link to v1: https://lore.kernel.org/r/20250311-topic-am62-ioddr-v2025-04-rc1-v1-0-666de9c105cb@baylibre.com

---
Markus Schneider-Pargmann (TI.com) (13):
      arm: mach-k3: Kconfig: Add symbol for IO+DDR Low Power Mode
      arm: mach-k3: common: Add CANUART wakeup check helpers
      arm: mach-k3: Remove CANUART IO isolation
      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 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    |   8 ++
 arch/arm/dts/k3-am62p5-sk-u-boot.dtsi    |   8 ++
 arch/arm/mach-k3/Kconfig                 |   8 ++
 arch/arm/mach-k3/am62ax/am62a7_init.c    |  13 +++
 arch/arm/mach-k3/am62px/am62p5_init.c    |  14 +++
 arch/arm/mach-k3/am62x/am625_init.c      |   4 +
 arch/arm/mach-k3/common.c                | 171 ++++++++++++++++++++++++++++++
 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                |  16 +++
 drivers/ram/k3-ddrss/Makefile            |   1 +
 drivers/ram/k3-ddrss/k3-ddrss-lpm.c      | 175 +++++++++++++++++++++++++++++++
 drivers/ram/k3-ddrss/k3-ddrss-lpm.h      |   9 ++
 drivers/ram/k3-ddrss/k3-ddrss.c          |  16 +++
 include/linux/soc/ti/ti_sci_protocol.h   |   9 ++
 18 files changed, 528 insertions(+)
---
base-commit: 0e0a198a68be71148f5ec27ef86796174f91436f
change-id: 20250306-topic-am62-ioddr-v2025-04-rc1-0b3a0ffe92b1

Best regards,
-- 
Markus Schneider-Pargmann (TI.com) <msp at baylibre.com>