Commit 57e06c11 authored by Alan Stern's avatar Alan Stern Committed by Greg Kroah-Hartman

EHCI: force high-speed devices to run at full speed

This patch (as710) adds a sysfs class-device attribute file named
"companion" for EHCI controllers.  The file contains a list of port
numbers that are dedicated to the companion controller; by writing a
port number to the file the user can force a high-speed device
attached directly to the computer to run at full speed.  (As far as I
know it is not possible to do this for a device attached to an
external hub.)  A port is removed from the file by writing the
negative of its port number.

Several users have asked for this facility and it seems like a useful
thing to have.  Every now and then one runs across a device which
behaves much better at full speed than at high speed.
Signed-off-by: default avatarAlan Stern <stern@rowland.harvard.edu>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent 625b5c9a
......@@ -388,6 +388,7 @@ static void ehci_stop (struct usb_hcd *hcd)
/* let companion controllers work when we aren't */
ehci_writel(ehci, 0, &ehci->regs->configured_flag);
remove_companion_file(ehci);
remove_debug_files (ehci);
/* root hub is shut down separately (first, when possible) */
......@@ -563,6 +564,7 @@ static int ehci_run (struct usb_hcd *hcd)
* since the class device isn't created that early.
*/
create_debug_files(ehci);
create_companion_file(ehci);
return 0;
}
......
......@@ -188,6 +188,103 @@ static int ehci_bus_resume (struct usb_hcd *hcd)
#endif /* CONFIG_PM */
/*-------------------------------------------------------------------------*/
/* Display the ports dedicated to the companion controller */
static ssize_t show_companion(struct class_device *class_dev, char *buf)
{
struct ehci_hcd *ehci;
int nports, index, n;
int count = PAGE_SIZE;
char *ptr = buf;
ehci = hcd_to_ehci(bus_to_hcd(class_get_devdata(class_dev)));
nports = HCS_N_PORTS(ehci->hcs_params);
for (index = 0; index < nports; ++index) {
if (test_bit(index, &ehci->companion_ports)) {
n = scnprintf(ptr, count, "%d\n", index + 1);
ptr += n;
count -= n;
}
}
return ptr - buf;
}
/*
* Dedicate or undedicate a port to the companion controller.
* Syntax is "[-]portnum", where a leading '-' sign means
* return control of the port to the EHCI controller.
*/
static ssize_t store_companion(struct class_device *class_dev,
const char *buf, size_t count)
{
struct ehci_hcd *ehci;
int portnum, new_owner, try;
u32 __iomem *status_reg;
u32 port_status;
ehci = hcd_to_ehci(bus_to_hcd(class_get_devdata(class_dev)));
new_owner = PORT_OWNER; /* Owned by companion */
if (sscanf(buf, "%d", &portnum) != 1)
return -EINVAL;
if (portnum < 0) {
portnum = - portnum;
new_owner = 0; /* Owned by EHCI */
}
if (portnum <= 0 || portnum > HCS_N_PORTS(ehci->hcs_params))
return -ENOENT;
status_reg = &ehci->regs->port_status[--portnum];
if (new_owner)
set_bit(portnum, &ehci->companion_ports);
else
clear_bit(portnum, &ehci->companion_ports);
/*
* The controller won't set the OWNER bit if the port is
* enabled, so this loop will sometimes require at least two
* iterations: one to disable the port and one to set OWNER.
*/
for (try = 4; try > 0; --try) {
spin_lock_irq(&ehci->lock);
port_status = ehci_readl(ehci, status_reg);
if ((port_status & PORT_OWNER) == new_owner
|| (port_status & (PORT_OWNER | PORT_CONNECT))
== 0)
try = 0;
else {
port_status ^= PORT_OWNER;
port_status &= ~(PORT_PE | PORT_RWC_BITS);
ehci_writel(ehci, port_status, status_reg);
}
spin_unlock_irq(&ehci->lock);
if (try > 1)
msleep(5);
}
return count;
}
static CLASS_DEVICE_ATTR(companion, 0644, show_companion, store_companion);
static inline void create_companion_file(struct ehci_hcd *ehci)
{
int i;
/* with integrated TT there is no companion! */
if (!ehci_is_TDI(ehci))
i = class_device_create_file(ehci_to_hcd(ehci)->self.class_dev,
&class_device_attr_companion);
}
static inline void remove_companion_file(struct ehci_hcd *ehci)
{
/* with integrated TT there is no companion! */
if (!ehci_is_TDI(ehci))
class_device_remove_file(ehci_to_hcd(ehci)->self.class_dev,
&class_device_attr_companion);
}
/*-------------------------------------------------------------------------*/
static int check_reset_complete (
......@@ -504,6 +601,16 @@ static int ehci_hub_control (
ehci_readl(ehci, status_reg));
}
/* transfer dedicated ports to the companion hc */
if ((temp & PORT_CONNECT) &&
test_bit(wIndex, &ehci->companion_ports)) {
temp &= ~PORT_RWC_BITS;
temp |= PORT_OWNER;
ehci_writel(ehci, temp, status_reg);
ehci_dbg(ehci, "port %d --> companion\n", wIndex + 1);
temp = ehci_readl(ehci, status_reg);
}
/*
* Even if OWNER is set, there's no harm letting khubd
* see the wPortStatus values (they should all be 0 except
......
......@@ -74,7 +74,11 @@ struct ehci_hcd { /* one per controller */
/* per root hub port */
unsigned long reset_done [EHCI_MAX_ROOT_PORTS];
unsigned long bus_suspended;
/* bit vectors (one bit per port) */
unsigned long bus_suspended; /* which ports were
already suspended at the start of a bus suspend */
unsigned long companion_ports; /* which ports are
dedicated to the companion controller */
/* per-HC memory pools (could be per-bus, but ...) */
struct dma_pool *qh_pool; /* qh per active urb */
......
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