[PATCH v2 00/12] usb: early: add support for early printk through USB3 debug port

From: Lu Baolu
Date: Tue Nov 03 2015 - 03:14:39 EST

This patch series adds support for early printk through USB3 debug port.
USB3 debug port is described in xHCI specification as an optional extended

The first patch adds a file in sysfs, through which users can check
whether the debug capability is supported by a specific host controller,
and the hardware state.

Patch 2 to 10 add the driver for xHCI debug capability. It interfaces with
the register set and provides the required ops (read/write/control) to upper
layers. Early printk is one consumer of these ops. The hooks for early printk
are introduced in patch 9. This design is similar to what we have done in

Patch 11 is a minor change to usb_debug module. This change is required to
bind usb_debug with the USB3 debug device.

Patch 12 is the design document and user guide.

Change log:
(1) Patch 1 re-implemented. "debugfs" has been replaced with sysfs.
The scope reduced from all extended capabilities to debug port
(2) Patch 11 changed. Removed unnecessary .bulk_out_size setting.

Lu Baolu (12):
usb: xhci: add sysfs file for xHCI debug port
x86: fixmap: add permanent fixmap for xhci debug port
usb: xhci: dbc: probe and setup xhci debug capability
usb: xhci: dbc: add support for Intel xHCI dbc quirk
usb: xhci: dbc: add debug buffer
usb: xhci: dbc: add bulk out and bulk in interfaces
usb: xhci: dbc: handle dbc-configured exit
usb: xhci: dbc: handle endpoint stall
x86: early_printk: add USB3 debug port earlyprintk support
usb: xhci: dbc: add handshake between debug target and host
usb: serial: usb_debug: add support for dbc debug device
usb: doc: add document for xHCI DbC driver

.../ABI/testing/sysfs-bus-pci-drivers-xhci_hcd | 23 +
Documentation/kernel-parameters.txt | 1 +
Documentation/usb/xhci-dbc.txt | 325 +++++
arch/x86/Kconfig.debug | 12 +
arch/x86/include/asm/fixmap.h | 4 +
arch/x86/kernel/early_printk.c | 5 +
drivers/usb/early/Makefile | 1 +
drivers/usb/early/xhci-dbc.c | 1407 ++++++++++++++++++++
drivers/usb/host/Makefile | 2 +-
drivers/usb/host/xhci-ext-caps.h | 14 +-
drivers/usb/host/xhci-sysfs.c | 100 ++
drivers/usb/host/xhci.c | 4 +
drivers/usb/host/xhci.h | 4 +
drivers/usb/serial/usb_debug.c | 28 +-
include/linux/usb/xhci-dbc.h | 224 ++++
16 files changed, 2157 insertions(+), 5 deletions(-)
create mode 100644 Documentation/ABI/testing/sysfs-bus-pci-drivers-xhci_hcd
create mode 100644 Documentation/usb/xhci-dbc.txt
create mode 100644 drivers/usb/early/xhci-dbc.c
create mode 100644 drivers/usb/host/xhci-sysfs.c
create mode 100644 include/linux/usb/xhci-dbc.h


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