[PATCH v5 10/12] usb: xhci: dbc: add handshake between debug target and host

Path	csiph.com!eternal-september.org!feeder.eternal-september.org!aioe.org!bofh.it!news.nic.it!robomod
From	Lu Baolu <baolu.lu@linux.intel.com>
Newsgroups	linux.kernel
Subject	[PATCH v5 10/12] usb: xhci: dbc: add handshake between debug target and host
Date	Wed, 02 Dec 2015 07:20:01 +0100
Message-ID	<qB8VH-3ru-5@gated-at.bofh.it> (permalink)
References	<qB8VH-3ru-3@gated-at.bofh.it>
X-Original-To	Mathias Nyman <mathias.nyman@intel.com>, Greg Kroah-Hartman <gregkh@linuxfoundation.org>
X-Extloop1	1
X-Ironport-Av	E=Sophos;i="5.20,371,1444719600"; d="scan'208";a="698543548"
X-Mailer	git-send-email 2.1.4
Sender	robomod@news.nic.it
List-ID	<linux-kernel.vger.kernel.org>
X-Mailing-List	linux-kernel@vger.kernel.org
Approved	robomod@news.nic.it
Lines	82
Organization	linux.* mail to news gateway
X-Original-Cc	Alan Stern <stern@rowland.harvard.edu>, linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, Lu Baolu <baolu.lu@linux.intel.com>
X-Original-Date	Wed, 2 Dec 2015 14:09:45 +0800
X-Original-Message-ID	<1449036587-13493-11-git-send-email-baolu.lu@linux.intel.com>
X-Original-References	<1449036587-13493-1-git-send-email-baolu.lu@linux.intel.com>
X-Original-Sender	linux-kernel-owner@vger.kernel.org
Xref	csiph.com linux.kernel:1281470

Show key headers only | View raw

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

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Back to linux.kernel | Previous | Next | Find similar | Unroll thread

Thread

[PATCH v5 10/12] usb: xhci: dbc: add handshake between debug target and host Lu Baolu <baolu.lu@linux.intel.com> - 2015-12-02 07:20 +0100

csiph-web