linux-kernel - [PATCH v3 0/2] remoteproc: imx_rproc: support non-blocking tx for i.MX7ULP

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Message-Id: <20240822-imx_rproc-v3-0-6d943723945d@nxp.com>
Date: Thu, 22 Aug 2024 21:48:48 +0800
From: "Peng Fan (OSS)" <peng.fan@....nxp.com>
To: Bjorn Andersson <andersson@...nel.org>, 
 Mathieu Poirier <mathieu.poirier@...aro.org>, 
 Shawn Guo <shawnguo@...nel.org>, Sascha Hauer <s.hauer@...gutronix.de>, 
 Pengutronix Kernel Team <kernel@...gutronix.de>, 
 Fabio Estevam <festevam@...il.com>, Daniel Baluta <daniel.baluta@....com>, 
 Iuliana Prodan <iuliana.prodan@....com>, Marek Vasut <marex@...x.de>
Cc: linux-remoteproc@...r.kernel.org, imx@...ts.linux.dev, 
 linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org, 
 Peng Fan <peng.fan@....com>
Subject: [PATCH v3 0/2] remoteproc: imx_rproc: support non-blocking tx for
 i.MX7ULP

The i.MX7ULP Cortex-A7 is under control of Cortex-M4. The i.MX7ULP Linux
poweroff and restart rely on rpmsg driver to send a message to Cortex-M4
firmware. Then Cortex-A7 could poweroff or restart by Cortex-M4 to
configure the i.MX7ULP power controller properly.

However the reboot and restart kernel common code use atomic notifier,
see kernel/reboot.c: do_kernel_power_off, do_kernel_restart.
Linux 'poweroff' cmd will trigger kernel 'do_kernel_power_off'
Linux 'reboot' cmd will trigger kernel 'do_kernel_restart'.

Power off and restart are totally different operations and are not
complementary. So need to make sure the mailbox be changed to non-blocking
mode in SYS_OFF_MODE_POWER_OFF_PREPARE and SYS_OFF_MODE_RESTART_PREPARE
stage. Otherwise with blocking tx mailbox, there will be kernel dump,
because of blocking mailbox will use wait_for_completion_timeout. In the
poweroff or restart case, there is no need to wait, because after M4 got
the message, M4 will put A7 to reboot or poweroff.

patch 1 is to support non-blocking tx mailbox channel
patch 2 is to switch to non-blocking tx for system poweroff or restart.

Signed-off-by: Peng Fan <peng.fan@....com>
---
Changes in v3:
- patch 2: Introduce an flags entry for dcfg and set IMX_RPROC_NEED_SYSTEM_OFF
  for i.MX7ULP, drop used "struct sys_off_data data" and add comment(per Frank).
  Drop R-b of patch 2 because of this change.
- Patch 1: commit log rewritten and R-b dropped.
  (Thanks to Daniel).
- Update patch 2 commit log and cover-letter to clarify reboot and
  poweroff are different operations and not complementary 
  (Thanks to Daniel).
- Link to v2: https://lore.kernel.org/r/20240719-imx_rproc-v2-0-cd8549aa3f1f@nxp.com

Changes in v2:
- Separated patch 5,6 from v1
- Update commit patch 1 with adding "No functional changes"
- Link to v1: https://lore.kernel.org/r/20240712-imx_rproc-v1-0-7bcf6732d328@nxp.com

---
Peng Fan (2):
      remoteproc: imx_rproc: Allow setting of the mailbox transmit mode
      remoteproc: imx_rproc: Add support for poweroff and reboot

 drivers/remoteproc/imx_rproc.c | 54 +++++++++++++++++++++++++++++++++++++-----
 drivers/remoteproc/imx_rproc.h |  4 ++++
 2 files changed, 52 insertions(+), 6 deletions(-)
---
base-commit: 33a32de2d79c051f27ed57c4ac90cdb406f91928
change-id: 20240712-imx_rproc-25f3ab753c58

Best regards,
-- 
Peng Fan <peng.fan@....com>