Message-ID: <ec49d7b5-abb5-45b6-94d6-8f06264e8b88@ti.com>
Date: Mon, 10 Nov 2025 16:55:26 -0600
From: Kendall Willis <k-willis@...com>
To: "Markus Schneider-Pargmann (TI.com)" <msp@...libre.com>, Nishanth Menon
	<nm@...com>, Tero Kristo <kristo@...nel.org>, Santosh Shilimkar
	<ssantosh@...nel.org>
CC: Vishal Mahaveer <vishalm@...com>, Kevin Hilman <khilman@...libre.com>,
	Dhruva Gole <d-gole@...com>, Sebin Francis <sebin.francis@...com>, "Akashdeep
 Kaur" <a-kaur@...com>, <linux-arm-kernel@...ts.infradead.org>,
	<linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v10 0/3] firmware: ti_sci: Partial-IO support

On 11/3/25 06:42, Markus Schneider-Pargmann (TI.com) wrote:
> Hi,
> 
> This series adds support for Partial-IO to the ti-sci driver,
> implementing the firmware interface necessary to enter this low power
> state. It processes the wakeup-source properties from the devicetree and
> communicates with the system firmware to enter Partial-IO mode when
> appropriate wakeup sources are enabled.
> 
> Partial-IO Overview
> ------------------
> Partial-IO is a low power system state in which nearly everything is
> turned off except the pins of the CANUART group (mcu_mcan0, mcu_mcan1,
> wkup_uart0 and mcu_uart0). These devices can trigger a wakeup of the
> system on pin activity. Note that this does not resume the system as the
> DDR is off as well. So this state can be considered a power-off state
> with wakeup capabilities.
> 
> A documentation can also be found in section 6.2.4 in the TRM:
>    https://www.ti.com/lit/pdf/spruiv7
> 
> Implementation Details
> ----------------------
> The complete Partial-IO feature requires three coordinated series, each
> handling a different aspect of the implementation:
> 
> 1. [MERGED] m_can driver series: Implements device-specific wakeup functionality
>     for m_can devices, allowing them to be set as wakeup sources. This is
>     now available in linux-next.
>     https://lore.kernel.org/r/20251001-topic-mcan-wakeup-source-v6-12-v10-0-4ab508ac5d1e@baylibre.com
> 
> 2. Devicetree series: Defines system states and wakeup sources in the
>     devicetree for am62, am62a and am62p.
>     https://gitlab.baylibre.com/msp8/linux/-/tree/topic/am62-dt-partialio/v6.18?ref_type=heads
>     https://lore.kernel.org/r/20251103-topic-am62-dt-partialio-v6-15-v5-0-b8d9ff5f2742@baylibre.com
> 
> 3. This series (TI-SCI firmware): Implements the firmware interface to
>     enter Partial-IO mode when appropriate wakeup sources are enabled.
> 
> Testing
> -------
> A test branch is available here that includes all patches required to
> test Partial-IO:
> 
> https://gitlab.baylibre.com/msp8/linux/-/tree/integration/am62-partialio/v6.18?ref_type=heads
> 
> After enabling Wake-on-LAN the system can be powered off and will enter
> the Partial-IO state in which it can be woken up by activity on the
> specific pins:
>      ethtool -s can0 wol p
>      ethtool -s can1 wol p
>      poweroff
> 
> These patches are tested on am62-lp-sk.
> 
> Best,
> Markus
> 
> Previous versions "firmware: ti_sci: Partial-IO support":
>   v1: https://lore.kernel.org/lkml/20240523080225.1288617-1-msp@baylibre.com/
>   v2: https://lore.kernel.org/lkml/20240729080101.3859701-1-msp@baylibre.com/
>   v3: https://lore.kernel.org/r/20241012-topic-am62-partialio-v6-13-b4-v3-0-f7c6c2739681@baylibre.com
>   v4: https://lore.kernel.org/r/20241219-topic-am62-partialio-v6-12-b4-v4-0-1cb8eabd407e@baylibre.com
>   v5: https://lore.kernel.org/r/20250306-topic-am62-partialio-v6-12-b4-v5-0-f9323d3744a2@baylibre.com
>   v6: https://lore.kernel.org/r/20250421-topic-am62-partialio-v6-12-b4-v6-0-3b5cefab1339@baylibre.com
>   v7: https://lore.kernel.org/r/20250812-topic-am62-partialio-v6-12-b4-v7-0-ac10865c2d87@baylibre.com
>   v8: https://lore.kernel.org/r/20251001-topic-am62-partialio-v6-12-b4-v8-0-76a742605110@baylibre.com
>   v9: https://lore.kernel.org/r/20251030-topic-am62-partialio-v6-12-b4-v9-0-074f55d9c16b@baylibre.com
> 
> Previous versions "can: m_can: Add am62 wakeup support":
>   v1: https://lore.kernel.org/lkml/20240523075347.1282395-1-msp@baylibre.com/
>   v2: https://lore.kernel.org/lkml/20240729074135.3850634-1-msp@baylibre.com/
>   v3: https://lore.kernel.org/lkml/20241011-topic-mcan-wakeup-source-v6-12-v3-0-9752c714ad12@baylibre.com
>   v4: https://lore.kernel.org/r/20241015-topic-mcan-wakeup-source-v6-12-v4-0-fdac1d1e7aa6@baylibre.com
>   v5: https://lore.kernel.org/r/20241028-topic-mcan-wakeup-source-v6-12-v5-0-33edc0aba629@baylibre.com
>   v6: https://lore.kernel.org/r/20241219-topic-mcan-wakeup-source-v6-12-v6-0-1356c7f7cfda@baylibre.com
> 
> Changes in v10:
>   - Remove unnecessary empty line
>   - Make ti_sci_cmd_prepare_sleep aware of PARTIAL_IO mode and the
>     not-expected response, because both Kendall and Andrew seem to
>     prefer this.
>   - Moved the removal of the ctx_lo, ctx_hi and debug_flags to the end of
>     the series so merging is optional.
> 
> Changes in v9:
>   - Rebased to next-20251029
> 
> Changes in v8:
>   - Add a patch to remove constant 0 argument passing to
>     ti_sci_cmd_prepare_sleep
>   - Move partial-io functions further up in the file before the first
>     static const initializations
> 
> Changes in v7:
>   - Rebase to v6.17-rc1
>   - Update the idle-state-name used to off-wake as introduced in
>     dt-schema
> 
> Changes in v6:
>   - Narrowed down the wakeup-source binding to phandle lists
>   - Split off the mcan and DT changes into separate series
> 
> Changes in v5:
>   - Rebased to v6.14-rc1
>   - Merged m_can and ti_sci series to avoid conflicts and show
>     dependencies more easily
>   - Added definitions of system-states for am62/am62a/am62p
>   - Moved wakeup-source definitions into board dts files as they require
>     a bit of support on the board.
>   - Updated ti_sci support to walk through the wakeup-source phandle
>     lists
>   - Added pinctrl settings for mcu_mcan0/1 on all boards
>   - Minor style updates for ti_sci support for transfers without response
>   - Update and move the dt-binding for wakeup-source from the m_can
>     binding to the dt-schema repository
> 
> Changes in v4:
>   - Rebased to v6.13-rc1
>   - Removed all regulator related structures from patches and implemented
>     the wakeup-source property use instead.
> 
> Changes in v3:
>   - Remove other modes declared for PREPARE_SLEEP as they probably won't
>     ever be used in upstream.
>   - Replace the wait loop after sending PREPARE_SLEEP with msleep and do
>     an emergency_restart if it exits
>   - Remove uarts from DT wakeup sources
>   - Split no response handling in ti_sci_do_xfer() into a separate patch
>     and use goto instead of if ()
>   - Remove DT binding parital-io-wakeup-sources. Instead I am modeling
>     the devices that are in the relevant group that are powered during
>     Partial-IO with the power supplies that are externally provided to
>     the SoC. In this case they are provided through 'vddshv_canuart'. All
>     devices using this regulator can be considered a potential wakeup
>     source if they are wakeup capable and wakeup enabled.
>   - Added devicetree patches adding vcc_3v3_sys regulator and
>     vddshv_canuart for am62-lp-sk
>   - Add pinctrl entries for am62-lp-sk to add WKUP_EN for mcu_mcan0 and
>     mcu_mcan1
> 
> Changes in v2:
>   - Rebase to v6.11-rc1
>   - dt-binding:
>      - Update commit message
>      - Add more verbose description of the new binding for a better
>        explanation.
>   - ti_sci driver:
>      - Combine ti_sci_do_send() into ti_sci_do_xfer and only wait on a
>        response if a flag is set.
>      - On failure to enter Partial-IO, do emergency_restart()
>      - Add comments
>      - Fix small things
> 
> Signed-off-by: Markus Schneider-Pargmann (TI.com) <msp@...libre.com>
> ---
> Markus Schneider-Pargmann (TI.com) (3):
>        firmware: ti_sci: Support transfers without response
>        firmware: ti_sci: Partial-IO support
>        firmware: ti_sci: Remove constant 0 function arguments
> 
>   drivers/firmware/ti_sci.c | 131 +++++++++++++++++++++++++++++++++++++++-------
>   drivers/firmware/ti_sci.h |   5 ++
>   2 files changed, 117 insertions(+), 19 deletions(-)
> ---
> base-commit: c9a389ffad27e7847c69f4d2b67ba56b77190209
> change-id: 20241008-topic-am62-partialio-v6-12-b4-c273fbac4447
> 
> Best regards,

LGTM, for the whole series,

Reviewed-by: Kendall Willis <k-willis@...com>

Best,
Kendall Willis

Powered by blists - more mailing lists