[PATCH v5 0/4] usb: early: add support for early printk through USB3 debug port
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. There isn't any precondition from xHCI host side for DbC to work. 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. This code is designed to be used only for kernel debugging when machine crashes very early before the console code is initialized. It makes the life of kernel debugging easier when people work with a modern machine without any legacy serial ports. --- Change log: 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 (4): usb: dbc: early driver for xhci debug capability x86: add support for earlyprintk via USB3 debug port usb: serial: usb_debug: add support for dbc debug device usb: doc: add document for USB3 debug port usage Documentation/kernel-parameters.txt |1 + Documentation/usb/usb3-debug-port.rst | 95 +++ arch/x86/Kconfig.debug| 14 + arch/x86/kernel/early_printk.c|5 + arch/x86/kernel/setup.c |7 + drivers/usb/Kconfig |3 + drivers/usb/Makefile |2 +- drivers/usb/early/Makefile|1 + drivers/usb/early/xhci-dbc.c | 1068 + drivers/usb/early/xhci-dbc.h | 205 +++ drivers/usb/serial/usb_debug.c| 28 +- include/linux/usb/xhci-dbgp.h | 22 + 12 files changed, 1447 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 -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH v5 0/4] usb: early: add support for early printk through USB3 debug port
Hi Greg, This patch series has been there for 2 months without further comments. Will you consider it for usb-next? Best regards, Lu Baolu On 11/15/2016 02:02 PM, Lu Baolu wrote: > 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. There > isn't any precondition from xHCI host side for DbC to work. > > 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. > > This code is designed to be used only for kernel debugging > when machine crashes very early before the console code is > initialized. It makes the life of kernel debugging easier > when people work with a modern machine without any legacy > serial ports. > > --- > Change log: > 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 (4): > usb: dbc: early driver for xhci debug capability > x86: add support for earlyprintk via USB3 debug port > usb: serial: usb_debug: add support for dbc debug device > usb: doc: add document for USB3 debug port usage > > Documentation/kernel-parameters.txt |1 + > Documentation/usb/usb3-debug-port.rst | 95 +++ > arch/x86/Kconfig.debug| 14 + > arch/x86/kernel/early_printk.c|5 + > arch/x86/kernel/setup.c |7 + > drivers/usb/Kconfig |3 + > drivers/usb/Makefile |2 +- > drivers/usb/early/Makefile|1 + > drivers/usb/early/xhci-dbc.c | 1068 > + > drivers/usb/early/xhci-dbc.h | 205 +++ > drivers/usb/serial/usb_debug.c| 28 +- > include/linux/usb/xhci-dbgp.h | 22 + > 12 files changed, 1447 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 > -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH v5 0/4] usb: early: add support for early printk through USB3 debug port
* Lu Baolu wrote: > 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. There > isn't any precondition from xHCI host side for DbC to work. > > 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. > > This code is designed to be used only for kernel debugging > when machine crashes very early before the console code is > initialized. It makes the life of kernel debugging easier > when people work with a modern machine without any legacy > serial ports. BTW., just a side note, some kernel developers (like PeterZ - and I do it sometimes too) remap early_printk to printk permanently and use it as their main printk facility - because printk() reliability has suffered over the last couple of years. So it's more than just early boot debugging - it's a very simple state-less logging facility to an external computer. Thanks, ngo -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH v5 0/4] usb: early: add support for early printk through USB3 debug port
On Wed, Jan 18, 2017 at 02:20:30PM +0800, Lu Baolu wrote: > Hi Greg, > > This patch series has been there for 2 months without > further comments. Will you consider it for usb-next? I needed acks from the x86 maintainers before I could take those patches. Can you resend the series and hopefully get them? thanks, greg k-h -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH v5 0/4] usb: early: add support for early printk through USB3 debug port
* Greg Kroah-Hartman wrote: > On Wed, Jan 18, 2017 at 02:20:30PM +0800, Lu Baolu wrote: > > Hi Greg, > > > > This patch series has been there for 2 months without > > further comments. Will you consider it for usb-next? > > I needed acks from the x86 maintainers before I could take those > patches. Can you resend the series and hopefully get them? Thanks for the reminder - the patches look mostly good to me, I have a few very minor observations, I'll reply to the patches. Thanks, Ingo -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH v5 0/4] usb: early: add support for early printk through USB3 debug port
On 19.01.2017 11:09, Ingo Molnar wrote: * Greg Kroah-Hartman wrote: On Wed, Jan 18, 2017 at 02:20:30PM +0800, Lu Baolu wrote: Hi Greg, This patch series has been there for 2 months without further comments. Will you consider it for usb-next? I needed acks from the x86 maintainers before I could take those patches. Can you resend the series and hopefully get them? Thanks for the reminder - the patches look mostly good to me, I have a few very minor observations, I'll reply to the patches. I have no further comments from xhci pov, If you send a new series fixing those minor observations I'll ack it -Mathias -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH v5 0/4] usb: early: add support for early printk through USB3 debug port
Hi Ingo, On 01/19/2017 05:12 PM, Ingo Molnar wrote: > * Lu Baolu wrote: > >> 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. There >> isn't any precondition from xHCI host side for DbC to work. >> >> 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. >> >> This code is designed to be used only for kernel debugging >> when machine crashes very early before the console code is >> initialized. It makes the life of kernel debugging easier >> when people work with a modern machine without any legacy >> serial ports. > BTW., just a side note, some kernel developers (like PeterZ - and I do it > sometimes too) remap early_printk to printk permanently and use it as their > main > printk facility - because printk() reliability has suffered over the last > couple > of years. > > So it's more than just early boot debugging - it's a very simple state-less > logging facility to an external computer. Thanks for the information. I will rework this message. Best regards, Lu Baolu -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
