USB: EHCI: EHCI 1.1 addendum: Basic LPM feature support

With this patch, the LPM capable EHCI host controller can put device
into L1 sleep state which is a mode that can enter/exit quickly, and
reduce power consumption.

Signed-off-by: Jacob Pan <jacob.jun.pan@intel.com>
Signed-off-by: Alek Du <alek.du@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 83 insertions, 0 deletions

diff --git a/drivers/usb/host/ehci-lpm.c b/drivers/usb/host/ehci-lpm.c
new file mode 100644
index 000000000000..b4d4d63c13ed
--- /dev/null
+++ b/drivers/usb/host/ehci-lpm.c
@@ -0,0 +1,83 @@
+/* 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;
+}