mbox series

[V6,0/3] usb: dwc2: Implement S2Idle for BCM2835

Message ID 20250217134132.36786-1-wahrenst@gmx.net
Headers show
Series usb: dwc2: Implement S2Idle for BCM2835 | expand

Message

Stefan Wahren Feb. 17, 2025, 1:41 p.m. UTC 
This series implement S2Idle support for the BCM2835, which is mostly
used on the Raspberry Pi boards.

Test steps:
- configure debug console (pl011 or mini UART) as wakeup source
- send system to idle state

   echo freeze > /sys/power/state

- wakeup system by console traffic

The series based on an idea of Doug Anderson. The USB domain is now
powered down and the USB devices are still usable after resume.

Here are some figures for the Raspberry Pi 1 (without any
devices connected except of a debug UART):

running but CPU idle = 1.67 W
S2Idle               = 1.33 W

In comparison with HDMI & USB keyboard connected (but neither active
nor wakeup source):

running but CPU idle = 1.82 W
S2Idle               = 1.33 W

The series has been successfully tested on the following platforms:
Raspberry Pi 1 B
Raspberry Pi 3 B+

Changes in V6:
- adapt cover letter to focus on DWC2 (was ARM: bcm2835: Implement initial
  S2Idle for Raspberry Pi)
- drop already applied patches and bcm2835_defconfig changes
- rebase on Linux 6.14-rc1

Changes in V5:
- add missing version

Changes in V4:
- added Reviewed-by from Doug
- fix DWC2 register backup
- add revert because of Raspberry Pi 3B+ regression

Changes in V3:
- replace old USB recovery patch with canary approach [3], which should
  work with other platforms

V5: https://lore.kernel.org/linux-usb/20241025103621.4780-1-wahrenst@gmx.net/

Stefan Wahren (3):
  usb: dwc2: gadget: Introduce register restore flags
  usb: dwc2: Refactor backup/restore of registers
  usb: dwc2: Implement recovery after PM domain off

 drivers/usb/dwc2/core.c     |   1 +
 drivers/usb/dwc2/core.h     |  23 ++++++-
 drivers/usb/dwc2/gadget.c   | 116 +++++++++++++++++++-----------------
 drivers/usb/dwc2/hcd.c      |  99 +++++++++++++++---------------
 drivers/usb/dwc2/platform.c |  38 ++++++++++++
 5 files changed, 171 insertions(+), 106 deletions(-)

--
2.34.1