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u-boot/common/usb_hub.c
Stephen Warren 74c0d756de usb: hub: don't check CONNECTION in hub_port_reset() 
One specific USB 3.0 device behaves strangely when reset by
usb_new_device()'s call to hub_port_reset(). For some reason, the device
appears to briefly drop off the bus when this second bus reset is
executed, yet if we retry this loop, it'll eventually come back after
another two resets.

If USB bus reset is executed over and over within usb_new_device()'s call
to hub_port_reset(), I see the following sequence of results, which
repeats as long as you want:

1) STAT_C_CONNECTION = 1 STAT_CONNECTION = 0  USB_PORT_STAT_ENABLE 0
2) STAT_C_CONNECTION = 1 STAT_CONNECTION = 1  USB_PORT_STAT_ENABLE 0
3) STAT_C_CONNECTION = 1 STAT_CONNECTION = 1  USB_PORT_STAT_ENABLE 1

The device in question is a SanDisk Ultra USB 3.0 16GB memory stick with
USB VID/PID 0x0781/0x5581.

In order to allow this device to work with U-Boot, ignore the
{C_,}CONNECTION bits in the status/change registers, and only use the
ENABLE bit to determine if the reset was successful.

To be honest, extensive investigation has failed to determine why this
problem occurs. I'd love to know! I don't know if it's caused by:
* A HW bug in the device
* A HW bug in the Tegra USB controller
* A SW bug in the U-Boot Tegra USB driver
* A SW bug in the U-Boot USB core

This issue only occurs when the device's USB3 pins are attached to the
host; if only the USB2 pins are connected the issue does not occur. The
USB3 controller on Tegra is in reset, so is not actively communicating
with the device at all - a USB3 analyzer confirms this. Slightly
unplugging the device (so the USB3 pins don't contact) or using a USB2
cable or hub as an intermediary avoids the problem. For some reason,
the Linux kernel (either on the same Tegra board, or on an x86 host)
has no issue with the device, and I observe no disconnections during
reset.

This change won't affect any USB device that already works, since such
devices could not currently be triggering the error return this patch
removes, or they wouldn't be working currently.

However, this patch is quite reliable in practice, hence I hope it's
acceptable to solve the problem.

The only potential fallout I can see from this patch is:

* A broken device that triggers C_CONNECTION/!CONNECTION now causes the
  loop in hub_port_reset() to run multiple times. If it never succeeds,
  this will cause "usb start" to take roughly 1s extra to execute.

* If the user unplugs a device while hub_port_reset() is executing, and
  very quickly swaps in a new device, hub_port_reset() might succeed on
  the new device. This would mean that any information cached about the
  original device (from the descriptor read in usb_new_device(), which
  simply caches the max packet size) might be invalid, which would cause
  problems talking to the new device. However, without this change, the
  new device wouldn't work anyway, so this is probably not much of a
  loss.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
2014-08-29 11:27:43 +02:00

562 lines
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/*
* Most of this source has been derived from the Linux USB
* project:
* (C) Copyright Linus Torvalds 1999
* (C) Copyright Johannes Erdfelt 1999-2001
* (C) Copyright Andreas Gal 1999
* (C) Copyright Gregory P. Smith 1999
* (C) Copyright Deti Fliegl 1999 (new USB architecture)
* (C) Copyright Randy Dunlap 2000
* (C) Copyright David Brownell 2000 (kernel hotplug, usb_device_id)
* (C) Copyright Yggdrasil Computing, Inc. 2000
* (usb_device_id matching changes by Adam J. Richter)
*
* Adapted for U-Boot:
* (C) Copyright 2001 Denis Peter, MPL AG Switzerland
*
* SPDX-License-Identifier: GPL-2.0+
*/
/****************************************************************************
* HUB "Driver"
* Probes device for being a hub and configurate it
*/
#include <common.h>
#include <command.h>
#include <asm/processor.h>
#include <asm/unaligned.h>
#include <linux/ctype.h>
#include <asm/byteorder.h>
#include <asm/unaligned.h>
#include <usb.h>
#ifdef CONFIG_4xx
#include <asm/4xx_pci.h>
#endif
#define USB_BUFSIZ 512
static struct usb_hub_device hub_dev[USB_MAX_HUB];
static int usb_hub_index;
__weak void usb_hub_reset_devices(int port)
{
return;
}
static int usb_get_hub_descriptor(struct usb_device *dev, void *data, int size)
{
return usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
USB_REQ_GET_DESCRIPTOR, USB_DIR_IN | USB_RT_HUB,
USB_DT_HUB << 8, 0, data, size, USB_CNTL_TIMEOUT);
}
static int usb_clear_port_feature(struct usb_device *dev, int port, int feature)
{
return usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
USB_REQ_CLEAR_FEATURE, USB_RT_PORT, feature,
port, NULL, 0, USB_CNTL_TIMEOUT);
}
static int usb_set_port_feature(struct usb_device *dev, int port, int feature)
{
return usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
USB_REQ_SET_FEATURE, USB_RT_PORT, feature,
port, NULL, 0, USB_CNTL_TIMEOUT);
}
static int usb_get_hub_status(struct usb_device *dev, void *data)
{
return usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
USB_REQ_GET_STATUS, USB_DIR_IN | USB_RT_HUB, 0, 0,
data, sizeof(struct usb_hub_status), USB_CNTL_TIMEOUT);
}
static int usb_get_port_status(struct usb_device *dev, int port, void *data)
{
return usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
USB_REQ_GET_STATUS, USB_DIR_IN | USB_RT_PORT, 0, port,
data, sizeof(struct usb_hub_status), USB_CNTL_TIMEOUT);
}
static void usb_hub_power_on(struct usb_hub_device *hub)
{
int i;
struct usb_device *dev;
unsigned pgood_delay = hub->desc.bPwrOn2PwrGood * 2;
ALLOC_CACHE_ALIGN_BUFFER(struct usb_port_status, portsts, 1);
unsigned short portstatus;
int ret;
dev = hub->pusb_dev;
/*
* Enable power to the ports:
* Here we Power-cycle the ports: aka,
* turning them off and turning on again.
*/
debug("enabling power on all ports\n");
for (i = 0; i < dev->maxchild; i++) {
usb_clear_port_feature(dev, i + 1, USB_PORT_FEAT_POWER);
debug("port %d returns %lX\n", i + 1, dev->status);
}
/* Wait at least 2*bPwrOn2PwrGood for PP to change */
mdelay(pgood_delay);
for (i = 0; i < dev->maxchild; i++) {
ret = usb_get_port_status(dev, i + 1, portsts);
if (ret < 0) {
debug("port %d: get_port_status failed\n", i + 1);
continue;
}
/*
* Check to confirm the state of Port Power:
* xHCI says "After modifying PP, s/w shall read
* PP and confirm that it has reached the desired state
* before modifying it again, undefined behavior may occur
* if this procedure is not followed".
* EHCI doesn't say anything like this, but no harm in keeping
* this.
*/
portstatus = le16_to_cpu(portsts->wPortStatus);
if (portstatus & (USB_PORT_STAT_POWER << 1)) {
debug("port %d: Port power change failed\n", i + 1);
continue;
}
}
for (i = 0; i < dev->maxchild; i++) {
usb_set_port_feature(dev, i + 1, USB_PORT_FEAT_POWER);
debug("port %d returns %lX\n", i + 1, dev->status);
}
/*
* Wait for power to become stable,
* plus spec-defined max time for device to connect
*/
mdelay(pgood_delay + 1000);
}
void usb_hub_reset(void)
{
usb_hub_index = 0;
}
static struct usb_hub_device *usb_hub_allocate(void)
{
if (usb_hub_index < USB_MAX_HUB)
return &hub_dev[usb_hub_index++];
printf("ERROR: USB_MAX_HUB (%d) reached\n", USB_MAX_HUB);
return NULL;
}
#define MAX_TRIES 5
static inline char *portspeed(int portstatus)
{
char *speed_str;
switch (portstatus & USB_PORT_STAT_SPEED_MASK) {
case USB_PORT_STAT_SUPER_SPEED:
speed_str = "5 Gb/s";
break;
case USB_PORT_STAT_HIGH_SPEED:
speed_str = "480 Mb/s";
break;
case USB_PORT_STAT_LOW_SPEED:
speed_str = "1.5 Mb/s";
break;
default:
speed_str = "12 Mb/s";
break;
}
return speed_str;
}
int hub_port_reset(struct usb_device *dev, int port,
unsigned short *portstat)
{
int tries;
ALLOC_CACHE_ALIGN_BUFFER(struct usb_port_status, portsts, 1);
unsigned short portstatus, portchange;
debug("hub_port_reset: resetting port %d...\n", port);
for (tries = 0; tries < MAX_TRIES; tries++) {
usb_set_port_feature(dev, port + 1, USB_PORT_FEAT_RESET);
mdelay(200);
if (usb_get_port_status(dev, port + 1, portsts) < 0) {
debug("get_port_status failed status %lX\n",
dev->status);
return -1;
}
portstatus = le16_to_cpu(portsts->wPortStatus);
portchange = le16_to_cpu(portsts->wPortChange);
debug("portstatus %x, change %x, %s\n", portstatus, portchange,
portspeed(portstatus));
debug("STAT_C_CONNECTION = %d STAT_CONNECTION = %d" \
" USB_PORT_STAT_ENABLE %d\n",
(portchange & USB_PORT_STAT_C_CONNECTION) ? 1 : 0,
(portstatus & USB_PORT_STAT_CONNECTION) ? 1 : 0,
(portstatus & USB_PORT_STAT_ENABLE) ? 1 : 0);
/*
* Perhaps we should check for the following here:
* - C_CONNECTION hasn't been set.
* - CONNECTION is still set.
*
* Doing so would ensure that the device is still connected
* to the bus, and hasn't been unplugged or replaced while the
* USB bus reset was going on.
*
* However, if we do that, then (at least) a San Disk Ultra
* USB 3.0 16GB device fails to reset on (at least) an NVIDIA
* Tegra Jetson TK1 board. For some reason, the device appears
* to briefly drop off the bus when this second bus reset is
* executed, yet if we retry this loop, it'll eventually come
* back after another reset or two.
*/
if (portstatus & USB_PORT_STAT_ENABLE)
break;
mdelay(200);
}
if (tries == MAX_TRIES) {
debug("Cannot enable port %i after %i retries, " \
"disabling port.\n", port + 1, MAX_TRIES);
debug("Maybe the USB cable is bad?\n");
return -1;
}
usb_clear_port_feature(dev, port + 1, USB_PORT_FEAT_C_RESET);
*portstat = portstatus;
return 0;
}
void usb_hub_port_connect_change(struct usb_device *dev, int port)
{
struct usb_device *usb;
ALLOC_CACHE_ALIGN_BUFFER(struct usb_port_status, portsts, 1);
unsigned short portstatus;
/* Check status */
if (usb_get_port_status(dev, port + 1, portsts) < 0) {
debug("get_port_status failed\n");
return;
}
portstatus = le16_to_cpu(portsts->wPortStatus);
debug("portstatus %x, change %x, %s\n",
portstatus,
le16_to_cpu(portsts->wPortChange),
portspeed(portstatus));
/* Clear the connection change status */
usb_clear_port_feature(dev, port + 1, USB_PORT_FEAT_C_CONNECTION);
/* Disconnect any existing devices under this port */
if (((!(portstatus & USB_PORT_STAT_CONNECTION)) &&
(!(portstatus & USB_PORT_STAT_ENABLE))) || (dev->children[port])) {
debug("usb_disconnect(&hub->children[port]);\n");
/* Return now if nothing is connected */
if (!(portstatus & USB_PORT_STAT_CONNECTION))
return;
}
mdelay(200);
/* Reset the port */
if (hub_port_reset(dev, port, &portstatus) < 0) {
printf("cannot reset port %i!?\n", port + 1);
return;
}
mdelay(200);
/* Allocate a new device struct for it */
usb = usb_alloc_new_device(dev->controller);
switch (portstatus & USB_PORT_STAT_SPEED_MASK) {
case USB_PORT_STAT_SUPER_SPEED:
usb->speed = USB_SPEED_SUPER;
break;
case USB_PORT_STAT_HIGH_SPEED:
usb->speed = USB_SPEED_HIGH;
break;
case USB_PORT_STAT_LOW_SPEED:
usb->speed = USB_SPEED_LOW;
break;
default:
usb->speed = USB_SPEED_FULL;
break;
}
dev->children[port] = usb;
usb->parent = dev;
usb->portnr = port + 1;
/* Run it through the hoops (find a driver, etc) */
if (usb_new_device(usb)) {
/* Woops, disable the port */
usb_free_device();
dev->children[port] = NULL;
debug("hub: disabling port %d\n", port + 1);
usb_clear_port_feature(dev, port + 1, USB_PORT_FEAT_ENABLE);
}
}
static int usb_hub_configure(struct usb_device *dev)
{
int i, length;
ALLOC_CACHE_ALIGN_BUFFER(unsigned char, buffer, USB_BUFSIZ);
unsigned char *bitmap;
short hubCharacteristics;
struct usb_hub_descriptor *descriptor;
struct usb_hub_device *hub;
__maybe_unused struct usb_hub_status *hubsts;
/* "allocate" Hub device */
hub = usb_hub_allocate();
if (hub == NULL)
return -1;
hub->pusb_dev = dev;
/* Get the the hub descriptor */
if (usb_get_hub_descriptor(dev, buffer, 4) < 0) {
debug("usb_hub_configure: failed to get hub " \
"descriptor, giving up %lX\n", dev->status);
return -1;
}
descriptor = (struct usb_hub_descriptor *)buffer;
length = min(descriptor->bLength, sizeof(struct usb_hub_descriptor));
if (usb_get_hub_descriptor(dev, buffer, length) < 0) {
debug("usb_hub_configure: failed to get hub " \
"descriptor 2nd giving up %lX\n", dev->status);
return -1;
}
memcpy((unsigned char *)&hub->desc, buffer, length);
/* adjust 16bit values */
put_unaligned(le16_to_cpu(get_unaligned(
&descriptor->wHubCharacteristics)),
&hub->desc.wHubCharacteristics);
/* set the bitmap */
bitmap = (unsigned char *)&hub->desc.DeviceRemovable[0];
/* devices not removable by default */
memset(bitmap, 0xff, (USB_MAXCHILDREN+1+7)/8);
bitmap = (unsigned char *)&hub->desc.PortPowerCtrlMask[0];
memset(bitmap, 0xff, (USB_MAXCHILDREN+1+7)/8); /* PowerMask = 1B */
for (i = 0; i < ((hub->desc.bNbrPorts + 1 + 7)/8); i++)
hub->desc.DeviceRemovable[i] = descriptor->DeviceRemovable[i];
for (i = 0; i < ((hub->desc.bNbrPorts + 1 + 7)/8); i++)
hub->desc.PortPowerCtrlMask[i] = descriptor->PortPowerCtrlMask[i];
dev->maxchild = descriptor->bNbrPorts;
debug("%d ports detected\n", dev->maxchild);
hubCharacteristics = get_unaligned(&hub->desc.wHubCharacteristics);
switch (hubCharacteristics & HUB_CHAR_LPSM) {
case 0x00:
debug("ganged power switching\n");
break;
case 0x01:
debug("individual port power switching\n");
break;
case 0x02:
case 0x03:
debug("unknown reserved power switching mode\n");
break;
}
if (hubCharacteristics & HUB_CHAR_COMPOUND)
debug("part of a compound device\n");
else
debug("standalone hub\n");
switch (hubCharacteristics & HUB_CHAR_OCPM) {
case 0x00:
debug("global over-current protection\n");
break;
case 0x08:
debug("individual port over-current protection\n");
break;
case 0x10:
case 0x18:
debug("no over-current protection\n");
break;
}
debug("power on to power good time: %dms\n",
descriptor->bPwrOn2PwrGood * 2);
debug("hub controller current requirement: %dmA\n",
descriptor->bHubContrCurrent);
for (i = 0; i < dev->maxchild; i++)
debug("port %d is%s removable\n", i + 1,
hub->desc.DeviceRemovable[(i + 1) / 8] & \
(1 << ((i + 1) % 8)) ? " not" : "");
if (sizeof(struct usb_hub_status) > USB_BUFSIZ) {
debug("usb_hub_configure: failed to get Status - " \
"too long: %d\n", descriptor->bLength);
return -1;
}
if (usb_get_hub_status(dev, buffer) < 0) {
debug("usb_hub_configure: failed to get Status %lX\n",
dev->status);
return -1;
}
#ifdef DEBUG
hubsts = (struct usb_hub_status *)buffer;
#endif
debug("get_hub_status returned status %X, change %X\n",
le16_to_cpu(hubsts->wHubStatus),
le16_to_cpu(hubsts->wHubChange));
debug("local power source is %s\n",
(le16_to_cpu(hubsts->wHubStatus) & HUB_STATUS_LOCAL_POWER) ? \
"lost (inactive)" : "good");
debug("%sover-current condition exists\n",
(le16_to_cpu(hubsts->wHubStatus) & HUB_STATUS_OVERCURRENT) ? \
"" : "no ");
usb_hub_power_on(hub);
/*
* Reset any devices that may be in a bad state when applying
* the power. This is a __weak function. Resetting of the devices
* should occur in the board file of the device.
*/
for (i = 0; i < dev->maxchild; i++)
usb_hub_reset_devices(i + 1);
for (i = 0; i < dev->maxchild; i++) {
ALLOC_CACHE_ALIGN_BUFFER(struct usb_port_status, portsts, 1);
unsigned short portstatus, portchange;
int ret;
ulong start = get_timer(0);
/*
* Wait for (whichever finishes first)
* - A maximum of 10 seconds
* This is a purely observational value driven by connecting
* a few broken pen drives and taking the max * 1.5 approach
* - connection_change and connection state to report same
* state
*/
do {
ret = usb_get_port_status(dev, i + 1, portsts);
if (ret < 0) {
debug("get_port_status failed\n");
break;
}
portstatus = le16_to_cpu(portsts->wPortStatus);
portchange = le16_to_cpu(portsts->wPortChange);
if ((portchange & USB_PORT_STAT_C_CONNECTION) ==
(portstatus & USB_PORT_STAT_CONNECTION))
break;
} while (get_timer(start) < CONFIG_SYS_HZ * 10);
if (ret < 0)
continue;
debug("Port %d Status %X Change %X\n",
i + 1, portstatus, portchange);
if (portchange & USB_PORT_STAT_C_CONNECTION) {
debug("port %d connection change\n", i + 1);
usb_hub_port_connect_change(dev, i);
}
if (portchange & USB_PORT_STAT_C_ENABLE) {
debug("port %d enable change, status %x\n",
i + 1, portstatus);
usb_clear_port_feature(dev, i + 1,
USB_PORT_FEAT_C_ENABLE);
/*
* The following hack causes a ghost device problem
* to Faraday EHCI
*/
#ifndef CONFIG_USB_EHCI_FARADAY
/* EM interference sometimes causes bad shielded USB
* devices to be shutdown by the hub, this hack enables
* them again. Works at least with mouse driver */
if (!(portstatus & USB_PORT_STAT_ENABLE) &&
(portstatus & USB_PORT_STAT_CONNECTION) &&
((dev->children[i]))) {
debug("already running port %i " \
"disabled by hub (EMI?), " \
"re-enabling...\n", i + 1);
usb_hub_port_connect_change(dev, i);
}
#endif
}
if (portstatus & USB_PORT_STAT_SUSPEND) {
debug("port %d suspend change\n", i + 1);
usb_clear_port_feature(dev, i + 1,
USB_PORT_FEAT_SUSPEND);
}
if (portchange & USB_PORT_STAT_C_OVERCURRENT) {
debug("port %d over-current change\n", i + 1);
usb_clear_port_feature(dev, i + 1,
USB_PORT_FEAT_C_OVER_CURRENT);
usb_hub_power_on(hub);
}
if (portchange & USB_PORT_STAT_C_RESET) {
debug("port %d reset change\n", i + 1);
usb_clear_port_feature(dev, i + 1,
USB_PORT_FEAT_C_RESET);
}
} /* end for i all ports */
return 0;
}
int usb_hub_probe(struct usb_device *dev, int ifnum)
{
struct usb_interface *iface;
struct usb_endpoint_descriptor *ep;
int ret;
iface = &dev->config.if_desc[ifnum];
/* Is it a hub? */
if (iface->desc.bInterfaceClass != USB_CLASS_HUB)
return 0;
/* Some hubs have a subclass of 1, which AFAICT according to the */
/* specs is not defined, but it works */
if ((iface->desc.bInterfaceSubClass != 0) &&
(iface->desc.bInterfaceSubClass != 1))
return 0;
/* Multiple endpoints? What kind of mutant ninja-hub is this? */
if (iface->desc.bNumEndpoints != 1)
return 0;
ep = &iface->ep_desc[0];
/* Output endpoint? Curiousier and curiousier.. */
if (!(ep->bEndpointAddress & USB_DIR_IN))
return 0;
/* If it's not an interrupt endpoint, we'd better punt! */
if ((ep->bmAttributes & 3) != 3)
return 0;
/* We found a hub */
debug("USB hub found\n");
ret = usb_hub_configure(dev);
return ret;
}
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