[U-Boot] [PATCH v9 2/2] console: usb: kbd: To improve TFTP booting performance

[Jim Lin <jilin@nvidia.com>]

TFTP booting is slow when a USB keyboard is installed and
stdin has usbkbd added.
This fix is to change Ctrl-C polling for USB keyboard to every second
when NET transfer is running.

Signed-off-by: Jim Lin <jilin@nvidia.com>
---
Changes in v2:
 1. Change configuration name from CONFIG_CTRLC_POLL_MS to CONFIG_CTRLC_POLL_S.
 2. New code will be executed only when CONFIG_CTRLC_POLL_S is defined in
    configuration header file.
 3. Add description in README.console.
Changes in v3:
 1. Move changes to common/usb_kbd.c and doc/README.usb
 2. Rename config setting to CONFIG_USBKB_TESTC_PERIOD.
 3. Remove slow response on USB-keyboard input when TFTP boot is not running.
Changes in v4:
 1. Remove changes in doc/README.usb, common/usb_kbd.c and
    CONFIG_USBKB_TESTC_PERIOD 
 2. Modify net/net.c
Changes in v5:
 1. Change variable name to ctrlc_t_start.
 2. Use two calls of get_timer(0) to get time gap.
Changes in v6:
 1. In common/usb_kbd.c, check net_busy_flag to determine whether we poll
    USB keyboard status.
 2. In include/usb.h, add external variable declaration net_busy_flag
Changes in v7:
 1. In common/usb_kbd.c and include/usb.h, add #ifdef CONFIG_CMD_NET.
 2. In common/usb_kbd.c, modify code to get correct time gap.
Changes in v8:
 1. Add __maybe_unused for variable kbd_testc_tms.
Changes in v9:
 1. Move external variable declaration from include/usb.h to common/usb_kbd.c

 common/usb_kbd.c |   15 +++++++++++++++
 1 files changed, 15 insertions(+), 0 deletions(-)

diff --git a/common/usb_kbd.c b/common/usb_kbd.c
index 3174b5e..46100e6 100644
--- a/common/usb_kbd.c
+++ b/common/usb_kbd.c
@@ -121,6 +121,11 @@ struct usb_kbd_pdata {
 	uint8_t		flags;
 };
 
+extern int __maybe_unused net_busy_flag;
+
+/* The period of time between two calls of usb_kbd_testc(). */
+static unsigned long __maybe_unused kbd_testc_tms;
+
 /* Generic keyboard event polling. */
 void usb_kbd_generic_poll(void)
 {
@@ -366,6 +371,16 @@ static int usb_kbd_testc(void)
 	struct usb_device *usb_kbd_dev;
 	struct usb_kbd_pdata *data;
 
+#ifdef CONFIG_CMD_NET
+	/*
+	 * If net_busy_flag is 1, NET transfer is running,
+	 * then we check key-pressed every second (first check may be
+	 * less than 1 second) to improve TFTP booting performance.
+	 */
+	if (net_busy_flag && (get_timer(kbd_testc_tms) < CONFIG_SYS_HZ))
+		return 0;
+	kbd_testc_tms = get_timer(0);
+#endif
 	dev = stdio_get_by_name(DEVNAME);
 	usb_kbd_dev = (struct usb_device *)dev->priv;
 	data = usb_kbd_dev->privptr;
-- 
1.7.7