xHCI debug capability (DbC) is an optional but standalone
functionality provided by an xHCI host controller. With DbC
hardware initialized, the system will present a debug device
through the USB3 debug port (normally the first USB3 port).
The debug device is fully compliant with the USB framework
and provides the equivalent of a very high performance (USB3)
full-duplex serial link between the debug host and target.
The DbC functionality is independent of xHCI host.
This patch set adds support for early printk functionality
through a USB3 debug port by 1) initializing and enabling
the DbC hardware during early boot; 2) registering a boot
console to the system so that early printk messages can go
through the USB3 debug port. It also includes some lines
of changes in usb_debug driver so that it can be bound when
a USB3 debug device is enumerated.
---
Change log:
v7->v8:
- refine the Kconfig help text.
- cleanup the unnecessary USB_EARLY_PRINTK bool.
- refine comments and trace messages in the driver.
- update usb3-debug-port.rst after internal reivew.
v6->v7:
- add a new patch "[PATCH 1/5] x86: add simple udelay
calibration" to make udelay() work for early drivers.
- [PATCH 2/5] usb: dbc: early driver for xhci debug capability
- add a kernel thread to handle error cases, such as cable
unplugging.
- Fixed several code styles pointed out by Ingo.
v5->v6:
- rebase the patches on top of the latest 4.10-rc4
- run successfully in a 32-bit kernel
- [PATCH 1/4]
- remove ugly linebreaks to make code more readable
- rename config names to make them consistency
- move sleep-able ioremap() out of the lock area
- rename reserved fields of register structures
- make the vertical tabulation of struct fields consistent
- [PATCH 2/4]
- remove "#ifdef" in the generic code by creating proper
wrappers in header file
- [PATCH 3/4]
- refine the title and commit message
- [PATCH 4/4]
- fix several typos and grammar errors in the document
v4->v5:
- add raw_spin_lock to make xdbc_bulk_write() reentrant.
v3->v4:
- Rename the document with .dst suffix.
- Add the list of hardware that has been succesfuly
tested on in the document.
v2->v3:
- Removed spinlock usage.
- Removed work queue usage.
- Refined the user guide document.
v1->v2:
- Refactor the duplicate code in xdbc_early_start() and
xdbc_handle_external_reset().
- Free resources when hardware not used any more.
- Refine the user guide document.
Lu Baolu (5):
x86: add simple udelay calibration
usb: early: add driver for xhci debug capability
x86: add support for earlyprintk via USB3 debug port
usb: serial: add dbc debug device support to usb_debug
usb: doc: add document for USB3 debug port usage
Documentation/admin-guide/kernel-parameters.txt | 1 +
Documentation/usb/usb3-debug-port.rst | 100 +++
arch/x86/Kconfig.debug | 23 +
arch/x86/kernel/early_printk.c | 5 +
arch/x86/kernel/setup.c | 26 +
drivers/usb/Makefile | 2 +-
drivers/usb/early/Makefile | 1 +
drivers/usb/early/xhci-dbc.c | 1014 +++++++++++++++++++++++
drivers/usb/early/xhci-dbc.h | 211 +++++
drivers/usb/serial/usb_debug.c | 28 +-
include/linux/usb/xhci-dbgp.h | 29 +
11 files changed, 1436 insertions(+), 4 deletions(-)
create mode 100644 Documentation/usb/usb3-debug-port.rst
create mode 100644 drivers/usb/early/xhci-dbc.c
create mode 100644 drivers/usb/early/xhci-dbc.h
create mode 100644 include/linux/usb/xhci-dbgp.h
--
2.1.4
