Nico Huber ([email protected]) just uploaded a new patch set to gerrit, 
which you can find at http://review.coreboot.org/1077

-gerrit

commit 2f51d9239824baaac28029b5cabb69f1cad06236
Author: Nico Huber <[email protected]>
Date:   Mon May 21 14:53:43 2012 +0200

    libpayload: Add timeouts in the EHCI USB driver
    
    We should always have some timeout when we wait for the hardware. This adds
    missing timeouts to the EHCI driver.
    
    Change-Id: I13ba532a6daf47510b16b8fdbe572a21f1d8b09c
    Signed-off-by: Nico Huber <[email protected]>
---
 payloads/libpayload/drivers/usb/ehci.c    |   90 ++++++++++++++++++++--------
 payloads/libpayload/drivers/usb/ehci_rh.c |   32 +++++++++--
 2 files changed, 91 insertions(+), 31 deletions(-)

diff --git a/payloads/libpayload/drivers/usb/ehci.c 
b/payloads/libpayload/drivers/usb/ehci.c
index 9500059..cd1e867 100644
--- a/payloads/libpayload/drivers/usb/ehci.c
+++ b/payloads/libpayload/drivers/usb/ehci.c
@@ -116,7 +116,21 @@ static int wait_for_tds(qtd_t *head)
        qtd_t *cur = head;
        while (1) {
                if (0) dump_td(virt_to_phys(cur));
-               while ((cur->token & QTD_ACTIVE) && !(cur->token & QTD_HALTED)) 
udelay(60);
+
+               /* wait for results */
+               /* TOTEST: how long to wait?
+                *         tested with some USB2.0 flash sticks:
+                *         slowest took around 180ms
+                */
+               int timeout = 10000; /* time out after 10000 * 50us == 500ms */
+               while ((cur->token & QTD_ACTIVE) && !(cur->token & QTD_HALTED)
+                               && timeout--)
+                       udelay(50);
+               if (timeout < 0) {
+                       printf("Error: ehci: queue transfer "
+                               "processing timed out.\n");
+                       return 1;
+               }
                if (cur->token & QTD_HALTED) {
                        printf("ERROR with packet\n");
                        dump_td(virt_to_phys(cur));
@@ -134,6 +148,51 @@ static int wait_for_tds(qtd_t *head)
        return result;
 }
 
+static int ehci_set_async_schedule(ehci_t *ehcic, int enable)
+{
+       /* Set async schedule status. */
+       if (enable)
+               ehcic->operation->usbcmd |= HC_OP_ASYNC_SCHED_EN;
+       else
+               ehcic->operation->usbcmd &= ~HC_OP_ASYNC_SCHED_EN;
+       /* Wait for the controller to accept async schedule status.
+        * This shouldn't take too long, but we should timeout nevertheless.
+        */
+       enable = enable ? HC_OP_ASYNC_SCHED_STAT : 0;
+       int timeout = 100; /* time out after 100ms */
+       while (((ehcic->operation->usbsts & HC_OP_ASYNC_SCHED_STAT) != enable)
+                       && timeout--)
+               mdelay(1);
+       if (timeout < 0) {
+               debug("ehci async schedule status change timed out.\n");
+               return 1;
+       }
+       return 0;
+}
+
+static int ehci_process_async_schedule(
+               ehci_t *ehcic, ehci_qh_t *qhead, qtd_t *head)
+{
+       int result;
+
+       /* make sure async schedule is disabled */
+       if (ehci_set_async_schedule(ehcic, 0)) return 1;
+
+       /* hook up QH */
+       ehcic->operation->asynclistaddr = virt_to_phys(qhead);
+
+       /* start async schedule */
+       if (ehci_set_async_schedule(ehcic, 1)) return 1;
+
+       /* wait for result */
+       result = wait_for_tds(head);
+
+       /* disable async schedule */
+       ehci_set_async_schedule(ehcic, 0);
+
+       return result;
+}
+
 static int ehci_bulk (endpoint_t *ep, int size, u8 *data, int finalize)
 {
        int result = 0;
@@ -179,19 +238,8 @@ static int ehci_bulk (endpoint_t *ep, int size, u8 *data, 
int finalize)
        qh->td.token |= (ep->toggle?QTD_TOGGLE_DATA1:0);
        head->token |= (ep->toggle?QTD_TOGGLE_DATA1:0);
 
-       /* hook up QH */
-       EHCI_INST(ep->dev->controller)->operation->asynclistaddr = 
virt_to_phys(qh);
-
-       /* start async schedule */
-       EHCI_INST(ep->dev->controller)->operation->usbcmd |= 
HC_OP_ASYNC_SCHED_EN;
-       while (!(EHCI_INST(ep->dev->controller)->operation->usbsts & 
HC_OP_ASYNC_SCHED_STAT)) ; /* wait */
-
-       /* wait for result */
-       result = wait_for_tds(head);
-
-       /* disable async schedule */
-       EHCI_INST(ep->dev->controller)->operation->usbcmd &= 
~HC_OP_ASYNC_SCHED_EN;
-       while (EHCI_INST(ep->dev->controller)->operation->usbsts & 
HC_OP_ASYNC_SCHED_STAT) ; /* wait */
+       result = ehci_process_async_schedule(
+                       EHCI_INST(ep->dev->controller), qh, head);
 
        ep->toggle = (cur->token & QTD_TOGGLE_MASK) >> QTD_TOGGLE_SHIFT;
 
@@ -268,18 +316,8 @@ static int ehci_control (usbdev_t *dev, direction_t dir, 
int drlen, void *devreq
        qh->epcaps = 3 << QH_PIPE_MULTIPLIER_SHIFT;
        qh->td.next_qtd = virt_to_phys(head);
 
-       /* hook up QH */
-       EHCI_INST(dev->controller)->operation->asynclistaddr = virt_to_phys(qh);
-
-       /* start async schedule */
-       EHCI_INST(dev->controller)->operation->usbcmd |= HC_OP_ASYNC_SCHED_EN;
-       while (!(EHCI_INST(dev->controller)->operation->usbsts & 
HC_OP_ASYNC_SCHED_STAT)) ; /* wait */
-
-       result = wait_for_tds(head);
-
-       /* disable async schedule */
-       EHCI_INST(dev->controller)->operation->usbcmd &= ~HC_OP_ASYNC_SCHED_EN;
-       while (EHCI_INST(dev->controller)->operation->usbsts & 
HC_OP_ASYNC_SCHED_STAT) ; /* wait */
+       result = ehci_process_async_schedule(
+                       EHCI_INST(dev->controller), qh, head);
 
        free_qh_and_tds(qh, head);
        return result;
diff --git a/payloads/libpayload/drivers/usb/ehci_rh.c 
b/payloads/libpayload/drivers/usb/ehci_rh.c
index dd073a3..aeead3b 100644
--- a/payloads/libpayload/drivers/usb/ehci_rh.c
+++ b/payloads/libpayload/drivers/usb/ehci_rh.c
@@ -55,9 +55,21 @@ ehci_rh_hand_over_port (usbdev_t *dev, int port)
 {
        debug("giving up port %x, it's USB1\n", port+1);
 
+       /* Clear ConnectStatusChange before evaluation */
+       /* RW/C register, so clear it by writing 1 */
+       RH_INST(dev)->ports[port] |= P_CONN_STATUS_CHANGE;
+
        /* Lowspeed device. Hand over to companion */
        RH_INST(dev)->ports[port] |= P_PORT_OWNER;
-       do {} while (!(RH_INST(dev)->ports[port] & P_CONN_STATUS_CHANGE));
+
+       /* TOTEST: how long to wait? trying 100ms for now */
+       int timeout = 10; /* timeout after 10 * 10ms == 100ms */
+       while (!(RH_INST(dev)->ports[port] & P_CONN_STATUS_CHANGE) && timeout--)
+               mdelay(10);
+       if (!(RH_INST(dev)->ports[port] & P_CONN_STATUS_CHANGE)) {
+               debug("Warning: Handing port over to companion timed out.\n");
+       }
+
        /* RW/C register, so clear it by writing 1 */
        RH_INST(dev)->ports[port] |= P_CONN_STATUS_CHANGE;
        return;
@@ -73,7 +85,7 @@ ehci_rh_scanport (usbdev_t *dev, int port)
        }
        /* device connected, handle */
        if (RH_INST(dev)->ports[port] & P_CURR_CONN_STATUS) {
-               mdelay(100);
+               mdelay(100); // usb20 spec 9.1.2
                if ((RH_INST(dev)->ports[port] & P_LINE_STATUS) == 
P_LINE_STATUS_LOWSPEED) {
                        ehci_rh_hand_over_port(dev, port);
                        return;
@@ -85,13 +97,23 @@ ehci_rh_scanport (usbdev_t *dev, int port)
                RH_INST(dev)->ports[port] = (RH_INST(dev)->ports[port] & 
~P_PORT_ENABLE) | P_PORT_RESET;
 
                /* Wait a bit while reset is active. */
-               mdelay(50);
+               mdelay(50); // usb20 spec 7.1.7.5 (TDRSTR)
 
                /* Deassert reset. */
                RH_INST(dev)->ports[port] &= ~P_PORT_RESET;
 
-               /* Wait for flag change to finish. The controller might take a 
while */
-               while (RH_INST(dev)->ports[port] & P_PORT_RESET) ;
+               /* Wait max. 2ms (ehci spec 2.3.9) for flag change to finish. */
+               int timeout = 20; /* time out after 20 * 100us == 2ms */
+               while ((RH_INST(dev)->ports[port] & P_PORT_RESET) && timeout--)
+                       udelay(100);
+               if (RH_INST(dev)->ports[port] & P_PORT_RESET) {
+                       printf("Error: ehci_rh: port reset timed out.\n");
+                       return;
+               }
+
+               /* If the host controller enabled the port, it's a high-speed
+                * device, otherwise it's full-speed.
+                */
                if (!(RH_INST(dev)->ports[port] & P_PORT_ENABLE)) {
                        ehci_rh_hand_over_port(dev, port);
                        return;

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