ehci-lpm.c

/* ehci-lpm.c EHCI HCD LPM support code
 * Copyright (c) 2008 - 2010,  Intel Corporation.
 * Author: Jacob Pan <jacob.jun.pan@intel.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/

/* this file is part of ehci-hcd.c */

static int ehci_lpm_set_da(struct ehci_hcd *ehci, int dev_addr, int port_num)
{
	u32 __iomem portsc;

	ehci_dbg(ehci, "set dev address %d for port %d\n", dev_addr, port_num);
	if (port_num > HCS_N_PORTS(ehci->hcs_params)) {
		ehci_dbg(ehci, "invalid port number %d\n", port_num);
		return -ENODEV;
	}
	portsc = ehci_readl(ehci, &ehci->regs->port_status[port_num-1]);
	portsc &= ~PORT_DEV_ADDR;
	portsc |= dev_addr<<25;
	ehci_writel(ehci, portsc, &ehci->regs->port_status[port_num-1]);
	return 0;
}

/*
 * this function is used to check if the device support LPM
 * if yes, mark the PORTSC register with PORT_LPM bit
 */
static int ehci_lpm_check(struct ehci_hcd *ehci, int port)
{
	u32 __iomem	*portsc ;
	u32 val32;
	int retval;

	portsc = &ehci->regs->port_status[port-1];
	val32 = ehci_readl(ehci, portsc);
	if (!(val32 & PORT_DEV_ADDR)) {
		ehci_dbg(ehci, "LPM: no device attached\n");
		return -ENODEV;
	}
	val32 |= PORT_LPM;
	ehci_writel(ehci, val32, portsc);
	msleep(5);
	val32 |= PORT_SUSPEND;
	ehci_dbg(ehci, "Sending LPM 0x%08x to port %d\n", val32, port);
	ehci_writel(ehci, val32, portsc);
	/* wait for ACK */
	msleep(10);
	retval = handshake(ehci, &ehci->regs->port_status[port-1], PORT_SSTS,
			PORTSC_SUSPEND_STS_ACK, 125);
	dbg_port(ehci, "LPM", port, val32);
	if (retval != -ETIMEDOUT) {
		ehci_dbg(ehci, "LPM: device ACK for LPM\n");
		val32 |= PORT_LPM;
		/*
		 * now device should be in L1 sleep, let's wake up the device
		 * so that we can complete enumeration.
		 */
		ehci_writel(ehci, val32, portsc);
		msleep(10);
		val32 |= PORT_RESUME;
		ehci_writel(ehci, val32, portsc);
	} else {
		ehci_dbg(ehci, "LPM: device does not ACK, disable LPM %d\n",
			retval);
		val32 &= ~PORT_LPM;
		retval = -ETIMEDOUT;
		ehci_writel(ehci, val32, portsc);
	}

	return retval;
}

static int __maybe_unused ehci_update_device(struct usb_hcd *hcd,
		struct usb_device *udev)
{
	struct ehci_hcd *ehci = hcd_to_ehci(hcd);
	int rc = 0;

	if (!udev->parent) /* udev is root hub itself, impossible */
		rc = -1;
	/* we only support lpm device connected to root hub yet */
	if (ehci->has_lpm && !udev->parent->parent) {
		rc = ehci_lpm_set_da(ehci, udev->devnum, udev->portnum);
		if (!rc)
			rc = ehci_lpm_check(ehci, udev->portnum);
	}
	return rc;
}