[coreboot-gerrit] New patch to review for coreboot: 03dc14e usbdebug: Reduce bus reset delays

[Kyösti Mälkki]

Kyösti Mälkki ([e-mail]) just uploaded a new patch set to gerrit, which you can find at http://review.coreboot.org/3863

-gerrit

commit 03dc14e6370654b218abf286684dc906184568e0
Author: Kyösti Mälkki 
Date:   Mon Aug 12 21:35:20 2013 +0300

usbdebug: Reduce bus reset delays

According to EHCI specification, host controller software stops
    the USB Reset condition by writing PORT_RESET=0. Software then
    poll-waits this bit until controller hardware has completed USB
    Reset sequence and read returns with PORT_RESET==0.

Change-Id: I6033c4d904c2af9eb16f5f3c1eb825776648cc1d
    Signed-off-by: Kyösti Mälkki 
---
 src/lib/usbdebug.c | 48 +++++++++++++++++++-----------------------------
 1 file changed, 19 insertions(+), 29 deletions(-)

diff --git a/src/lib/usbdebug.c b/src/lib/usbdebug.c
index c7c5520..1393fb3 100644
--- a/src/lib/usbdebug.c
+++ b/src/lib/usbdebug.c
@@ -340,7 +340,6 @@ static int dbgp_control_msg(struct ehci_dbg_port *ehci_debug, unsigned devnum, i
 static int ehci_reset_port(struct ehci_regs *ehci_regs, int port)
 {
    u32 portsc;
-	u32 delay_time, delay_ms;
    int loop;

/* Reset the usb debug port */
@@ -349,39 +348,30 @@ static int ehci_reset_port(struct ehci_regs *ehci_regs, int port)
    portsc |= PORT_RESET;
    write32((unsigned long)&ehci_regs->port_status[port - 1], portsc);

-	delay_ms = HUB_ROOT_RESET_TIME;
-	for (delay_time = 0; delay_time < HUB_RESET_TIMEOUT;
-	     delay_time += delay_ms) {
-		dbgp_mdelay(delay_ms);
+	dbgp_mdelay(HUB_ROOT_RESET_TIME);

+	portsc = read32((unsigned long)&ehci_regs->port_status[port - 1]);
+	write32((unsigned long)&ehci_regs->port_status[port - 1],
+			portsc & ~(PORT_RWC_BITS | PORT_RESET));
+
+	loop = 100;
+	do {
+		dbgp_mdelay(1);
    	portsc = read32((unsigned long)&ehci_regs->port_status[port - 1]);
-		if (portsc & PORT_RESET) {
-			/* force reset to complete */
-			loop = 2;
-			write32((unsigned long)&ehci_regs->port_status[port - 1],
-					portsc & ~(PORT_RWC_BITS | PORT_RESET));
-			do {
-				dbgp_mdelay(delay_ms);
-				portsc = read32((unsigned long)&ehci_regs->port_status[port - 1]);
-				delay_time += delay_ms;
-			} while ((portsc & PORT_RESET) && (--loop > 0));
-			if (!loop) {
-				printk(BIOS_DEBUG, "ehci_reset_port forced done");
-			}
-		}
+	} while ((portsc & PORT_RESET) && (--loop > 0));

-		/* Device went away? */
-		if (!(portsc & PORT_CONNECT))
-			return -1; //-ENOTCONN;
+	/* Device went away? */
+	if (!(portsc & PORT_CONNECT))
+		return -1; //-ENOTCONN;

-		/* bomb out completely if something weird happened */
-		if ((portsc & PORT_CSC))
-			return -2; //-EINVAL;
+	/* bomb out completely if something weird happened */
+	if ((portsc & PORT_CSC))
+		return -2; //-EINVAL;
+
+	/* If we've finished resetting, then break out of the loop */
+	if (!(portsc & PORT_RESET) && (portsc & PORT_PE))
+		return 0;

-		/* If we've finished resetting, then break out of the loop */
-		if (!(portsc & PORT_RESET) && (portsc & PORT_PE))
-			return 0;
-	}
    return -3; //-EBUSY;
 }