USB: EHCI: remove unused Link Power Management code

This patch (as1622) removes the USB-2.1 Link Power Management code
from the ehci-hcd driver.  This code was never integrated with
usbcore, it is full of bugs, and it was not getting used by anybody.

However, the debugging code for dumping the LPM-related fields in the
EHCI registers is left in place.  In theory it might be useful to see
these values, even though we don't use them.

This essentially amounts to a partial revert of commit
aa4d8342 (USB: EHCI: EHCI 1.1
addendum: preparation) and an almost full revert of commit
48f24970 (USB: EHCI: EHCI 1.1
addendum: Basic LPM feature support) plus its follow-ons.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/host/ehci-dbg.c

@@ -337,11 +337,6 @@ static int debug_async_open(struct inode *, struct file *);
 static int debug_periodic_open(struct inode *, struct file *);
 static int debug_registers_open(struct inode *, struct file *);
 static int debug_async_open(struct inode *, struct file *);
-static ssize_t debug_lpm_read(struct file *file, char __user *user_buf,
-				   size_t count, loff_t *ppos);
-static ssize_t debug_lpm_write(struct file *file, const char __user *buffer,
-			      size_t count, loff_t *ppos);
-static int debug_lpm_close(struct inode *inode, struct file *file);
 
 static ssize_t debug_output(struct file*, char __user*, size_t, loff_t*);
 static int debug_close(struct inode *, struct file *);
@@ -367,14 +362,6 @@ static const struct file_operations debug_registers_fops = {
 	.release	= debug_close,
 	.llseek		= default_llseek,
 };
-static const struct file_operations debug_lpm_fops = {
-	.owner		= THIS_MODULE,
-	.open		= simple_open,
-	.read		= debug_lpm_read,
-	.write		= debug_lpm_write,
-	.release	= debug_lpm_close,
-	.llseek		= noop_llseek,
-};
 
 static struct dentry *ehci_debug_root;
 
@@ -956,86 +943,6 @@ static int debug_registers_open(struct inode *inode, struct file *file)
 	return file->private_data ? 0 : -ENOMEM;
 }
 
-static int debug_lpm_close(struct inode *inode, struct file *file)
-{
-	return 0;
-}
-
-static ssize_t debug_lpm_read(struct file *file, char __user *user_buf,
-				   size_t count, loff_t *ppos)
-{
-	/* TODO: show lpm stats */
-	return 0;
-}
-
-static ssize_t debug_lpm_write(struct file *file, const char __user *user_buf,
-			      size_t count, loff_t *ppos)
-{
-	struct usb_hcd		*hcd;
-	struct ehci_hcd		*ehci;
-	char buf[50];
-	size_t len;
-	u32 temp;
-	unsigned long port;
-	u32 __iomem	*portsc ;
-	u32 params;
-
-	hcd = bus_to_hcd(file->private_data);
-	ehci = hcd_to_ehci(hcd);
-
-	len = min(count, sizeof(buf) - 1);
-	if (copy_from_user(buf, user_buf, len))
-		return -EFAULT;
-	buf[len] = '\0';
-	if (len > 0 && buf[len - 1] == '\n')
-		buf[len - 1] = '\0';
-
-	if (strncmp(buf, "enable", 5) == 0) {
-		if (strict_strtoul(buf + 7, 10, &port))
-			return -EINVAL;
-		params = ehci_readl(ehci, &ehci->caps->hcs_params);
-		if (port > HCS_N_PORTS(params)) {
-			ehci_dbg(ehci, "ERR: LPM on bad port %lu\n", port);
-			return -ENODEV;
-		}
-		portsc = &ehci->regs->port_status[port-1];
-		temp = ehci_readl(ehci, portsc);
-		if (!(temp & PORT_DEV_ADDR)) {
-			ehci_dbg(ehci, "LPM: no device attached\n");
-			return -ENODEV;
-		}
-		temp |= PORT_LPM;
-		ehci_writel(ehci, temp, portsc);
-		printk(KERN_INFO "force enable LPM for port %lu\n", port);
-	} else if (strncmp(buf, "hird=", 5) == 0) {
-		unsigned long hird;
-		if (strict_strtoul(buf + 5, 16, &hird))
-			return -EINVAL;
-		printk(KERN_INFO "setting hird %s %lu\n", buf + 6, hird);
-		ehci->command = (ehci->command & ~CMD_HIRD) | (hird << 24);
-		ehci_writel(ehci, ehci->command, &ehci->regs->command);
-	} else if (strncmp(buf, "disable", 7) == 0) {
-		if (strict_strtoul(buf + 8, 10, &port))
-			return -EINVAL;
-		params = ehci_readl(ehci, &ehci->caps->hcs_params);
-		if (port > HCS_N_PORTS(params)) {
-			ehci_dbg(ehci, "ERR: LPM off bad port %lu\n", port);
-			return -ENODEV;
-		}
-		portsc = &ehci->regs->port_status[port-1];
-		temp = ehci_readl(ehci, portsc);
-		if (!(temp & PORT_DEV_ADDR)) {
-			ehci_dbg(ehci, "ERR: no device attached\n");
-			return -ENODEV;
-		}
-		temp &= ~PORT_LPM;
-		ehci_writel(ehci, temp, portsc);
-		printk(KERN_INFO "disabled LPM for port %lu\n", port);
-	} else
-		return -EOPNOTSUPP;
-	return count;
-}
-
 static inline void create_debug_files (struct ehci_hcd *ehci)
 {
 	struct usb_bus *bus = &ehci_to_hcd(ehci)->self;
@@ -1056,10 +963,6 @@ static inline void create_debug_files (struct ehci_hcd *ehci)
 						    &debug_registers_fops))
 		goto file_error;
 
-	if (!debugfs_create_file("lpm", S_IRUGO|S_IWUSR, ehci->debug_dir, bus,
-						    &debug_lpm_fops))
-		goto file_error;
-
 	return;
 
 file_error:

drivers/usb/host/ehci-hcd.c

@@ -39,7 +39,6 @@
 #include <linux/dma-mapping.h>
 #include <linux/debugfs.h>
 #include <linux/slab.h>
-#include <linux/uaccess.h>
 
 #include <asm/byteorder.h>
 #include <asm/io.h>
@@ -108,11 +107,6 @@ static bool ignore_oc = 0;
 module_param (ignore_oc, bool, S_IRUGO);
 MODULE_PARM_DESC (ignore_oc, "ignore bogus hardware overcurrent indications");
 
-/* for link power management(LPM) feature */
-static unsigned int hird;
-module_param(hird, int, S_IRUGO);
-MODULE_PARM_DESC(hird, "host initiated resume duration, +1 for each 75us");
-
 #define	INTR_MASK (STS_IAA | STS_FATAL | STS_PCD | STS_ERR | STS_INT)
 
 /*-------------------------------------------------------------------------*/
@@ -318,7 +312,6 @@ static void end_unlink_intr(struct ehci_hcd *ehci, struct ehci_qh *qh);
 
 #include "ehci-timer.c"
 #include "ehci-hub.c"
-#include "ehci-lpm.c"
 #include "ehci-mem.c"
 #include "ehci-q.c"
 #include "ehci-sched.c"
@@ -580,17 +573,6 @@ static int ehci_init(struct usb_hcd *hcd)
 		temp &= ~(3 << 2);
 		temp |= (EHCI_TUNE_FLS << 2);
 	}
-	if (HCC_LPM(hcc_params)) {
-		/* support link power management EHCI 1.1 addendum */
-		ehci_dbg(ehci, "support lpm\n");
-		ehci->has_lpm = 1;
-		if (hird > 0xf) {
-			ehci_dbg(ehci, "hird %d invalid, use default 0",
-			hird);
-			hird = 0;
-		}
-		temp |= hird << 24;
-	}
 	ehci->command = temp;
 
 	/* Accept arbitrarily long scatter-gather lists */

drivers/usb/host/ehci-hub.c

@@ -777,11 +777,6 @@ static int ehci_hub_control (
 						status_reg);
 			break;
 		case USB_PORT_FEAT_C_CONNECTION:
-			if (ehci->has_lpm) {
-				/* clear PORTSC bits on disconnect */
-				temp &= ~PORT_LPM;
-				temp &= ~PORT_DEV_ADDR;
-			}
 			ehci_writel(ehci, temp | PORT_CSC, status_reg);
 			break;
 		case USB_PORT_FEAT_C_OVER_CURRENT:

drivers/usb/host/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;
-}

drivers/usb/host/ehci-pci.c

@@ -202,11 +202,6 @@ static int ehci_pci_setup(struct usb_hcd *hcd)
 		break;
 	case PCI_VENDOR_ID_INTEL:
 		ehci->need_io_watchdog = 0;
-		if (pdev->device == 0x0806 || pdev->device == 0x0811
-				|| pdev->device == 0x0829) {
-			ehci_info(ehci, "disable lpm for langwell/penwell\n");
-			ehci->has_lpm = 0;
-		}
 		break;
 	case PCI_VENDOR_ID_NVIDIA:
 		switch (pdev->device) {
@@ -216,8 +211,7 @@ static int ehci_pci_setup(struct usb_hcd *hcd)
 		 * devices with PPCD enabled.
 		 */
 		case 0x0d9d:
-			ehci_info(ehci, "disable lpm/ppcd for nvidia mcp89");
-			ehci->has_lpm = 0;
+			ehci_info(ehci, "disable ppcd for nvidia mcp89\n");
 			ehci->has_ppcd = 0;
 			ehci->command &= ~CMD_PPCEE;
 			break;
@@ -425,11 +419,6 @@ static const struct hc_driver ehci_pci_hc_driver = {
 	.relinquish_port =	ehci_relinquish_port,
 	.port_handed_over =	ehci_port_handed_over,
 
-	/*
-	 * call back when device connected and addressed
-	 */
-	.update_device =	ehci_update_device,
-
 	.clear_tt_buffer_complete	= ehci_clear_tt_buffer_complete,
 };
 

drivers/usb/host/ehci-vt8500.c

@@ -61,11 +61,6 @@ static const struct hc_driver vt8500_ehci_hc_driver = {
 	.relinquish_port	= ehci_relinquish_port,
 	.port_handed_over	= ehci_port_handed_over,
 
-	/*
-	 * call back when device connected and addressed
-	 */
-	.update_device =	ehci_update_device,
-
 	.clear_tt_buffer_complete	= ehci_clear_tt_buffer_complete,
 };
 

drivers/usb/host/ehci.h

@@ -206,7 +206,6 @@ struct ehci_hcd {			/* one per controller */
 	#define OHCI_HCCTRL_LEN         0x4
 	__hc32			*ohci_hcctrl_reg;
 	unsigned		has_hostpc:1;
-	unsigned		has_lpm:1;  /* support link power management */
 	unsigned		has_ppcd:1; /* support per-port change bits */
 	u8			sbrn;		/* packed release number */