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

drivers/usb/host/ehci-hcd.c

+2 −0
Original line number Diff line number Diff line
@@ -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;

}

drivers/usb/host/ehci-hub.c

+107 −0
Original line number Diff line number Diff line
@@ -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

drivers/usb/host/ehci.h

+5 −1
Original line number Diff line number Diff line
@@ -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 */