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...@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
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