Re: [PATCH v6 10/12] usb: dbc: add handshake between debug target and host

Re: [PATCH v6 10/12] usb: dbc: add handshake between debug target and host

[Julia Lawall]

Please check.  As far as I can see, the call to early_xdbc_read ends up at
xdbc_bulk_transfer, which return negative error codes on failure.

julia

On Tue, 26 Jan 2016, kbuild test robot wrote:

> CC: kbuild-all@01.org
> In-Reply-To: <1453781665-4714-11-git-send-email-baolu.lu@linux.intel.com>
> TO: Lu Baolu <baolu.lu@linux.intel.com>
> CC: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> CC: linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, Lu Baolu <baolu.lu@linux.intel.com>
>
> Hi Lu,
>
> [auto build test WARNING on usb/usb-testing]
> [also build test WARNING on v4.5-rc1 next-20160125]
> [if your patch is applied to the wrong git tree, please drop us a note to help improving the system]
>
> url:    https://github.com/0day-ci/linux/commits/Lu-Baolu/usb-early-add-support-for-early-printk-through-USB3-debug-port/20160126-122049
> base:   https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing
> :::::: branch date: 5 hours ago
> :::::: commit date: 5 hours ago
>
> >> drivers/usb/early/xhci-dbc.c:917:6-10: WARNING: Unsigned expression compared with zero: size > 0
>
> git remote add linux-review https://github.com/0day-ci/linux
> git remote update linux-review
> git checkout cdae956781925bbc269faa7f40c931a2825be11a
> vim +917 drivers/usb/early/xhci-dbc.c
>
> 5319db53 Lu Baolu 2016-01-26  901
> 5319db53 Lu Baolu 2016-01-26  902  	/* hand over the owner of host from BIOS */
> 5319db53 Lu Baolu 2016-01-26  903  	xdbc_bios_handoff();
> 5319db53 Lu Baolu 2016-01-26  904
> 5319db53 Lu Baolu 2016-01-26  905  	ret = xdbc_setup();
> 5319db53 Lu Baolu 2016-01-26  906  	if (ret < 0) {
> 5319db53 Lu Baolu 2016-01-26  907  		pr_notice("failed to setup xHCI DbC connection\n");
> 5319db53 Lu Baolu 2016-01-26  908  		xdbcp->xhci_base = NULL;
> 5319db53 Lu Baolu 2016-01-26  909  		xdbcp->xdbc_reg = NULL;
> 12cd5775 Lu Baolu 2016-01-26  910  		xdbc_dump_debug_buffer();
> 5319db53 Lu Baolu 2016-01-26  911  		return ret;
> 5319db53 Lu Baolu 2016-01-26  912  	}
> 5319db53 Lu Baolu 2016-01-26  913
> cdae9567 Lu Baolu 2016-01-26  914  	while (retry > 0) {
> cdae9567 Lu Baolu 2016-01-26  915  		early_xdbc_write(NULL, ping, strlen(ping));
> cdae9567 Lu Baolu 2016-01-26  916  		size = early_xdbc_read(NULL, pong, 64);
> cdae9567 Lu Baolu 2016-01-26 @917  		if (size > 0) {
> cdae9567 Lu Baolu 2016-01-26  918  			xdbc_trace("%s: pong message: %s\n", __func__, pong);
> cdae9567 Lu Baolu 2016-01-26  919  			if (pong[0] == 'Y' || pong[0] == 'y')
> cdae9567 Lu Baolu 2016-01-26  920  				break;
> cdae9567 Lu Baolu 2016-01-26  921  		} else {
> cdae9567 Lu Baolu 2016-01-26  922  			xdbc_trace("%s: pong message error %d\n",
> cdae9567 Lu Baolu 2016-01-26  923  				__func__, size);
> cdae9567 Lu Baolu 2016-01-26  924  		}
> cdae9567 Lu Baolu 2016-01-26  925
>
> ---
> 0-DAY kernel test infrastructure                Open Source Technology Center
> https://lists.01.org/pipermail/kbuild-all                   Intel Corporation
>

Re: [PATCH v6 10/12] usb: dbc: add handshake between debug target and host

[Lu Baolu]

On 01/26/2016 06:40 PM, Julia Lawall wrote:
> Please check.  As far as I can see, the call to early_xdbc_read ends up at
> xdbc_bulk_transfer, which return negative error codes on failure.

Good catch. Thank you. I will correct it.

>
> julia
>
> On Tue, 26 Jan 2016, kbuild test robot wrote:
>
>> CC: kbuild-all@01.org
>> In-Reply-To: <1453781665-4714-11-git-send-email-baolu.lu@linux.intel.com>
>> TO: Lu Baolu <baolu.lu@linux.intel.com>
>> CC: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
>> CC: linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, Lu Baolu <baolu.lu@linux.intel.com>
>>
>> Hi Lu,
>>
>> [auto build test WARNING on usb/usb-testing]
>> [also build test WARNING on v4.5-rc1 next-20160125]
>> [if your patch is applied to the wrong git tree, please drop us a note to help improving the system]
>>
>> url:    https://github.com/0day-ci/linux/commits/Lu-Baolu/usb-early-add-support-for-early-printk-through-USB3-debug-port/20160126-122049
>> base:   https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing
>> :::::: branch date: 5 hours ago
>> :::::: commit date: 5 hours ago
>>
>>>> drivers/usb/early/xhci-dbc.c:917:6-10: WARNING: Unsigned expression compared with zero: size > 0
>> git remote add linux-review https://github.com/0day-ci/linux
>> git remote update linux-review
>> git checkout cdae956781925bbc269faa7f40c931a2825be11a
>> vim +917 drivers/usb/early/xhci-dbc.c
>>
>> 5319db53 Lu Baolu 2016-01-26  901
>> 5319db53 Lu Baolu 2016-01-26  902  	/* hand over the owner of host from BIOS */
>> 5319db53 Lu Baolu 2016-01-26  903  	xdbc_bios_handoff();
>> 5319db53 Lu Baolu 2016-01-26  904
>> 5319db53 Lu Baolu 2016-01-26  905  	ret = xdbc_setup();
>> 5319db53 Lu Baolu 2016-01-26  906  	if (ret < 0) {
>> 5319db53 Lu Baolu 2016-01-26  907  		pr_notice("failed to setup xHCI DbC connection\n");
>> 5319db53 Lu Baolu 2016-01-26  908  		xdbcp->xhci_base = NULL;
>> 5319db53 Lu Baolu 2016-01-26  909  		xdbcp->xdbc_reg = NULL;
>> 12cd5775 Lu Baolu 2016-01-26  910  		xdbc_dump_debug_buffer();
>> 5319db53 Lu Baolu 2016-01-26  911  		return ret;
>> 5319db53 Lu Baolu 2016-01-26  912  	}
>> 5319db53 Lu Baolu 2016-01-26  913
>> cdae9567 Lu Baolu 2016-01-26  914  	while (retry > 0) {
>> cdae9567 Lu Baolu 2016-01-26  915  		early_xdbc_write(NULL, ping, strlen(ping));
>> cdae9567 Lu Baolu 2016-01-26  916  		size = early_xdbc_read(NULL, pong, 64);
>> cdae9567 Lu Baolu 2016-01-26 @917  		if (size > 0) {
>> cdae9567 Lu Baolu 2016-01-26  918  			xdbc_trace("%s: pong message: %s\n", __func__, pong);
>> cdae9567 Lu Baolu 2016-01-26  919  			if (pong[0] == 'Y' || pong[0] == 'y')
>> cdae9567 Lu Baolu 2016-01-26  920  				break;
>> cdae9567 Lu Baolu 2016-01-26  921  		} else {
>> cdae9567 Lu Baolu 2016-01-26  922  			xdbc_trace("%s: pong message error %d\n",
>> cdae9567 Lu Baolu 2016-01-26  923  				__func__, size);
>> cdae9567 Lu Baolu 2016-01-26  924  		}
>> cdae9567 Lu Baolu 2016-01-26  925
>>
>> ---
>> 0-DAY kernel test infrastructure                Open Source Technology Center
>> https://lists.01.org/pipermail/kbuild-all                   Intel Corporation
>>

[PATCH v6 00/12] usb: early: add support for early printk through USB3 debug port

[Lu Baolu]

Hi,

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

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
drivers/usb/early/ehci-dbgp.c.

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:
v1->v2:
(1) Patch 1 re-implemented. "debugfs" has been replaced with sysfs.
    The scope reduced from all extended capabilities to debug port
    specific.
(2) Patch 11 changed. Removed unnecessary .bulk_out_size setting.

v2->v3:
(1) Patch 11 got acked by Johan Hovold.

v3->v4:
(1) Patch 1 code refactored by using xhci_find_ext_cap_by_id() helper.
(2) Patch 3 "bus hung state" changed to "port hung state" in commit message.
(3) Patch 12 added verified platform information.

v4->v5:
(1) Patch 1 & 3 code refactored by using xhci_find_next_ext_cap() helper.
(2) Patch 12 updated with more user guide information.
(3) All patches rebased to the new usb-next branch which contains commit
    d5ddcdf(xhci: rework xhci extended capability list parsing functions).

v5->v6:
(1) refresh the patches against 4.5-rc1.
(2) change "usb: xhci: dbc" to "usb: dbc" in the patch titles as they
    are not part of xhci driver.

Lu Baolu (12):
  usb: xhci: add sysfs file for xHCI debug port
  x86: fixmap: add permanent fixmap for xhci debug port
  usb: dbc: probe and setup xhci debug capability
  usb: dbc: add support for Intel xHCI dbc quirk
  usb: dbc: add debug buffer
  usb: dbc: add bulk out and bulk in interfaces
  usb: dbc: handle dbc-configured exit
  usb: dbc: handle endpoint stall
  x86: early_printk: add USB3 debug port earlyprintk support
  usb: 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                     |  350 +++++
 MAINTAINERS                                        |    8 +
 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                       | 1394 ++++++++++++++++++++
 drivers/usb/host/Makefile                          |    2 +-
 drivers/usb/host/xhci-ext-caps.h                   |    5 +
 drivers/usb/host/xhci-sysfs.c                      |   65 +
 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, 2126 insertions(+), 4 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

-- 
2.1.4

[PATCH v6 10/12] usb: dbc: add handshake between debug target and host

[Lu Baolu]

After DbC setup, debug target needs to wait until tty driver and
application (e.g. mincom) on debug taget start.  Otherwise, out
messages might be ignored.

This patch adds a ping/pong mechanism between debug target and
host. Debug target will be waiting there until user presses 'Y'
or 'y' in the tty application.

Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
---
 drivers/usb/early/xhci-dbc.c | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/drivers/usb/early/xhci-dbc.c b/drivers/usb/early/xhci-dbc.c
index 6c24ba0..37c5c87 100644
--- a/drivers/usb/early/xhci-dbc.c
+++ b/drivers/usb/early/xhci-dbc.c
@@ -32,6 +32,9 @@
 static struct xdbc_state xdbc_stat;
 static struct xdbc_state *xdbcp = &xdbc_stat;
 
+static int early_xdbc_read(struct console *con, char *str, unsigned n);
+static void early_xdbc_write(struct console *con, const char *str, u32 n);
+
 #ifdef DBC_DEBUG
 #define	XDBC_DEBUG_BUF_SIZE	(PAGE_SIZE * 32)
 #define	MSG_MAX_LINE		128
@@ -860,8 +863,12 @@ int __init early_xdbc_init(char *s)
 {
 	u32 bus = 0, dev = 0, func = 0;
 	unsigned long dbgp_num = 0;
+	char *ping = "Press Y to continue...\n";
+	char pong[64];
+	size_t size;
 	u32 offset;
 	int ret;
+	int retry = 20;
 
 	if (!early_pci_allowed())
 		return -EPERM;
@@ -904,6 +911,21 @@ int __init early_xdbc_init(char *s)
 		return ret;
 	}
 
+	while (retry > 0) {
+		early_xdbc_write(NULL, ping, strlen(ping));
+		size = early_xdbc_read(NULL, pong, 64);
+		if (size > 0) {
+			xdbc_trace("%s: pong message: %s\n", __func__, pong);
+			if (pong[0] == 'Y' || pong[0] == 'y')
+				break;
+		} else {
+			xdbc_trace("%s: pong message error %d\n",
+				__func__, size);
+		}
+
+		retry--;
+	}
+
 	return 0;
 }
 
@@ -1325,6 +1347,11 @@ int xdbc_bulk_write(const char *bytes, int size)
  * Start a bulk-in or bulk-out transfer, wait until transfer completion
  * or error. Return the count of actually transferred bytes or error.
  */
+static int early_xdbc_read(struct console *con, char *str, unsigned n)
+{
+	return xdbc_bulk_read(str, n, 0);
+}
+
 static void early_xdbc_write(struct console *con, const char *str, u32 n)
 {
 	int chunk, ret;
-- 
2.1.4