USB: cxacru: ADSL state management

The device has commands to start/stop the ADSL function, so this adds a
sysfs attribute to allow it to be started/stopped/restarted.  It also stops
polling the device for status when the ADSL function is disabled.

There are no problems with sending multiple start or stop commands, even
with a fast loop of them the device still works.  There is no need to
protect the restart process from further user actions while it's waiting
for 1.5s.

Signed-off-by: Simon Arlott <simon@fire.lp0.eu>
Cc: Duncan Sands <duncan.sands@math.u-psud.fr>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 227 insertions, 9 deletions

diff --git a/drivers/usb/atm/cxacru.c b/drivers/usb/atm/cxacru.c
index cdcdfed9449d..30b7bfbc985a 100644
--- a/drivers/usb/atm/cxacru.c
+++ b/drivers/usb/atm/cxacru.c
@@ -4,6 +4,7 @@
  *
  *  Copyright (C) 2004 David Woodhouse, Duncan Sands, Roman Kagan
  *  Copyright (C) 2005 Duncan Sands, Roman Kagan (rkagan % mail ! ru)
+ *  Copyright (C) 2007 Simon Arlott
  *
  *  This program is free software; you can redistribute it and/or modify it
  *  under the terms of the GNU General Public License as published by the Free
@@ -146,6 +147,13 @@ enum cxacru_info_idx {
         CXINF_MAX = 0x1c,
 };
 
+enum cxacru_poll_state {
+        CXPOLL_STOPPING,
+        CXPOLL_STOPPED,
+        CXPOLL_POLLING,
+        CXPOLL_SHUTDOWN
+};
+
 struct cxacru_modem_type {
         u32 pll_f_clk;
         u32 pll_b_clk;
@@ -158,8 +166,12 @@ struct cxacru_data {
         const struct cxacru_modem_type *modem_type;
 
         int line_status;
+        struct mutex adsl_state_serialize;
+        int adsl_status;
         struct delayed_work poll_work;
         u32 card_info[CXINF_MAX];
+        struct mutex poll_state_serialize;
+        int poll_state;
 
         /* contol handles */
         struct mutex cm_serialize;
@@ -171,10 +183,18 @@ struct cxacru_data {
         struct completion snd_done;
 };
 
+static int cxacru_cm(struct cxacru_data *instance, enum cxacru_cm_request cm,
+        u8 *wdata, int wsize, u8 *rdata, int rsize);
+static void cxacru_poll_status(struct work_struct *work);
+
 /* Card info exported through sysfs */
 #define CXACRU__ATTR_INIT(_name) \
 static DEVICE_ATTR(_name, S_IRUGO, cxacru_sysfs_show_##_name, NULL)
 
+#define CXACRU_CMD_INIT(_name) \
+static DEVICE_ATTR(_name, S_IWUSR | S_IRUGO, \
+        cxacru_sysfs_show_##_name, cxacru_sysfs_store_##_name)
+
 #define CXACRU_ATTR_INIT(_value, _type, _name) \
 static ssize_t cxacru_sysfs_show_##_name(struct device *dev, \
         struct device_attribute *attr, char *buf) \
@@ -187,9 +207,11 @@ static ssize_t cxacru_sysfs_show_##_name(struct device *dev, \
 CXACRU__ATTR_INIT(_name)
 
 #define CXACRU_ATTR_CREATE(_v, _t, _name) CXACRU_DEVICE_CREATE_FILE(_name)
+#define CXACRU_CMD_CREATE(_name)          CXACRU_DEVICE_CREATE_FILE(_name)
 #define CXACRU__ATTR_CREATE(_name)        CXACRU_DEVICE_CREATE_FILE(_name)
 
 #define CXACRU_ATTR_REMOVE(_v, _t, _name) CXACRU_DEVICE_REMOVE_FILE(_name)
+#define CXACRU_CMD_REMOVE(_name)          CXACRU_DEVICE_REMOVE_FILE(_name)
 #define CXACRU__ATTR_REMOVE(_name)        CXACRU_DEVICE_REMOVE_FILE(_name)
 
 static ssize_t cxacru_sysfs_showattr_u32(u32 value, char *buf)
@@ -278,6 +300,119 @@ static ssize_t cxacru_sysfs_show_mac_address(struct device *dev,
                         atm_dev->esi[3], atm_dev->esi[4], atm_dev->esi[5]);
 }
 
+static ssize_t cxacru_sysfs_show_adsl_state(struct device *dev,
+        struct device_attribute *attr, char *buf)
+{
+        struct usb_interface *intf = to_usb_interface(dev);
+        struct usbatm_data *usbatm_instance = usb_get_intfdata(intf);
+        struct cxacru_data *instance = usbatm_instance->driver_data;
+        u32 value = instance->card_info[CXINF_LINE_STARTABLE];
+
+        switch (value) {
+        case 0: return snprintf(buf, PAGE_SIZE, "running\n");
+        case 1: return snprintf(buf, PAGE_SIZE, "stopped\n");
+        default: return snprintf(buf, PAGE_SIZE, "unknown (%u)\n", value);
+        }
+}
+
+static ssize_t cxacru_sysfs_store_adsl_state(struct device *dev,
+        struct device_attribute *attr, const char *buf, size_t count)
+{
+        struct usb_interface *intf = to_usb_interface(dev);
+        struct usbatm_data *usbatm_instance = usb_get_intfdata(intf);
+        struct cxacru_data *instance = usbatm_instance->driver_data;
+        int ret;
+        int poll = -1;
+        char str_cmd[8];
+        int len = strlen(buf);
+
+        if (!capable(CAP_NET_ADMIN))
+                return -EACCES;
+
+        ret = sscanf(buf, "%7s", str_cmd);
+        if (ret != 1)
+                return -EINVAL;
+        ret = 0;
+
+        if (mutex_lock_interruptible(&instance->adsl_state_serialize))
+                return -ERESTARTSYS;
+
+        if (!strcmp(str_cmd, "stop") || !strcmp(str_cmd, "restart")) {
+                ret = cxacru_cm(instance, CM_REQUEST_CHIP_ADSL_LINE_STOP, NULL, 0, NULL, 0);
+                if (ret < 0) {
+                        atm_err(usbatm_instance, "change adsl state:"
+                                " CHIP_ADSL_LINE_STOP returned %d\n", ret);
+
+                        ret = -EIO;
+                } else {
+                        ret = len;
+                        poll = CXPOLL_STOPPED;
+                }
+        }
+
+        /* Line status is only updated every second
+         * and the device appears to only react to
+         * START/STOP every second too. Wait 1.5s to
+         * be sure that restart will have an effect. */
+        if (!strcmp(str_cmd, "restart"))
+                msleep(1500);
+
+        if (!strcmp(str_cmd, "start") || !strcmp(str_cmd, "restart")) {
+                ret = cxacru_cm(instance, CM_REQUEST_CHIP_ADSL_LINE_START, NULL, 0, NULL, 0);
+                if (ret < 0) {
+                        atm_err(usbatm_instance, "change adsl state:"
+                                " CHIP_ADSL_LINE_START returned %d\n", ret);
+
+                        ret = -EIO;
+                } else {
+                        ret = len;
+                        poll = CXPOLL_POLLING;
+                }
+        }
+
+        if (!strcmp(str_cmd, "poll")) {
+                ret = len;
+                poll = CXPOLL_POLLING;
+        }
+
+        if (ret == 0) {
+                ret = -EINVAL;
+                poll = -1;
+        }
+
+        if (poll == CXPOLL_POLLING) {
+                mutex_lock(&instance->poll_state_serialize);
+                switch (instance->poll_state) {
+                case CXPOLL_STOPPED:
+                        /* start polling */
+                        instance->poll_state = CXPOLL_POLLING;
+                        break;
+
+                case CXPOLL_STOPPING:
+                        /* abort stop request */
+                        instance->poll_state = CXPOLL_POLLING;
+                case CXPOLL_POLLING:
+                case CXPOLL_SHUTDOWN:
+                        /* don't start polling */
+                        poll = -1;
+                }
+                mutex_unlock(&instance->poll_state_serialize);
+        } else if (poll == CXPOLL_STOPPED) {
+                mutex_lock(&instance->poll_state_serialize);
+                /* request stop */
+                if (instance->poll_state == CXPOLL_POLLING)
+                        instance->poll_state = CXPOLL_STOPPING;
+                mutex_unlock(&instance->poll_state_serialize);
+        }
+
+        mutex_unlock(&instance->adsl_state_serialize);
+
+        if (poll == CXPOLL_POLLING)
+                cxacru_poll_status(&instance->poll_work.work);
+
+        return ret;
+}
+
 /*
  * All device attributes are included in CXACRU_ALL_FILES
  * so that the same list can be used multiple times:
@@ -312,7 +447,8 @@ CXACRU_ATTR_##_action(CXINF_LINE_STARTABLE,            bool, line_startable); \
 CXACRU_ATTR_##_action(CXINF_MODULATION,                MODU, modulation); \
 CXACRU_ATTR_##_action(CXINF_ADSL_HEADEND,              u32,  adsl_headend); \
 CXACRU_ATTR_##_action(CXINF_ADSL_HEADEND_ENVIRONMENT,  u32,  adsl_headend_environment); \
-CXACRU_ATTR_##_action(CXINF_CONTROLLER_VERSION,        u32,  adsl_controller_version);
+CXACRU_ATTR_##_action(CXINF_CONTROLLER_VERSION,        u32,  adsl_controller_version); \
+CXACRU_CMD_##_action(                                        adsl_state);
 
 CXACRU_ALL_FILES(INIT);
 
@@ -493,8 +629,6 @@ static int cxacru_card_status(struct cxacru_data *instance)
         return 0;
 }
 
-static void cxacru_poll_status(struct work_struct *work);
-
 static int cxacru_atm_start(struct usbatm_data *usbatm_instance,
                 struct atm_dev *atm_dev)
 {
@@ -503,6 +637,7 @@ static int cxacru_atm_start(struct usbatm_data *usbatm_instance,
         struct atm_dev *atm_dev = usbatm_instance->atm_dev;
         */
         int ret;
+        int start_polling = 1;
 
         dbg("cxacru_atm_start");
 
@@ -515,14 +650,35 @@ static int cxacru_atm_start(struct usbatm_data *usbatm_instance,
         }
 
         /* start ADSL */
+        mutex_lock(&instance->adsl_state_serialize);
         ret = cxacru_cm(instance, CM_REQUEST_CHIP_ADSL_LINE_START, NULL, 0, NULL, 0);
         if (ret < 0) {
                 atm_err(usbatm_instance, "cxacru_atm_start: CHIP_ADSL_LINE_START returned %d\n", ret);
+                mutex_unlock(&instance->adsl_state_serialize);
                 return ret;
         }
 
         /* Start status polling */
-        cxacru_poll_status(&instance->poll_work.work);
+        mutex_lock(&instance->poll_state_serialize);
+        switch (instance->poll_state) {
+        case CXPOLL_STOPPED:
+                /* start polling */
+                instance->poll_state = CXPOLL_POLLING;
+                break;
+
+        case CXPOLL_STOPPING:
+                /* abort stop request */
+                instance->poll_state = CXPOLL_POLLING;
+        case CXPOLL_POLLING:
+        case CXPOLL_SHUTDOWN:
+                /* don't start polling */
+                start_polling = 0;
+        }
+        mutex_unlock(&instance->poll_state_serialize);
+        mutex_unlock(&instance->adsl_state_serialize);
+
+        if (start_polling)
+                cxacru_poll_status(&instance->poll_work.work);
         return 0;
 }
 
@@ -533,16 +689,46 @@ static void cxacru_poll_status(struct work_struct *work)
         u32 buf[CXINF_MAX] = {};
         struct usbatm_data *usbatm = instance->usbatm;
         struct atm_dev *atm_dev = usbatm->atm_dev;
+        int keep_polling = 1;
         int ret;
 
         ret = cxacru_cm_get_array(instance, CM_REQUEST_CARD_INFO_GET, buf, CXINF_MAX);
         if (ret < 0) {
-                atm_warn(usbatm, "poll status: error %d\n", ret);
+                if (ret != -ESHUTDOWN)
+                        atm_warn(usbatm, "poll status: error %d\n", ret);
+
+                mutex_lock(&instance->poll_state_serialize);
+                if (instance->poll_state != CXPOLL_SHUTDOWN) {
+                        instance->poll_state = CXPOLL_STOPPED;
+
+                        if (ret != -ESHUTDOWN)
+                                atm_warn(usbatm, "polling disabled, set adsl_state"
+                                                " to 'start' or 'poll' to resume\n");
+                }
+                mutex_unlock(&instance->poll_state_serialize);
                 goto reschedule;
         }
 
         memcpy(instance->card_info, buf, sizeof(instance->card_info));
 
+        if (instance->adsl_status != buf[CXINF_LINE_STARTABLE]) {
+                instance->adsl_status = buf[CXINF_LINE_STARTABLE];
+
+                switch (instance->adsl_status) {
+                case 0:
+                        atm_printk(KERN_INFO, usbatm, "ADSL state: running\n");
+                        break;
+
+                case 1:
+                        atm_printk(KERN_INFO, usbatm, "ADSL state: stopped\n");
+                        break;
+
+                default:
+                        atm_printk(KERN_INFO, usbatm, "Unknown adsl status %02x\n", instance->adsl_status);
+                        break;
+                }
+        }
+
         if (instance->line_status == buf[CXINF_LINE_STATUS])
                 goto reschedule;
 
@@ -597,8 +783,20 @@ static void cxacru_poll_status(struct work_struct *work)
                 break;
         }
 reschedule:
-        schedule_delayed_work(&instance->poll_work,
-                        round_jiffies_relative(msecs_to_jiffies(POLL_INTERVAL*1000)));
+
+        mutex_lock(&instance->poll_state_serialize);
+        if (instance->poll_state == CXPOLL_STOPPING &&
+                                instance->adsl_status == 1 && /* stopped */
+                                instance->line_status == 0) /* down */
+                instance->poll_state = CXPOLL_STOPPED;
+
+        if (instance->poll_state == CXPOLL_STOPPED)
+                keep_polling = 0;
+        mutex_unlock(&instance->poll_state_serialize);
+
+        if (keep_polling)
+                schedule_delayed_work(&instance->poll_work,
+                                round_jiffies_relative(POLL_INTERVAL*HZ));
 }
 
 static int cxacru_fw(struct usb_device *usb_dev, enum cxacru_fw_request fw,
@@ -835,6 +1033,13 @@ static int cxacru_bind(struct usbatm_data *usbatm_instance,
         instance->modem_type = (struct cxacru_modem_type *) id->driver_info;
         memset(instance->card_info, 0, sizeof(instance->card_info));
 
+        mutex_init(&instance->poll_state_serialize);
+        instance->poll_state = CXPOLL_STOPPED;
+        instance->line_status = -1;
+        instance->adsl_status = -1;
+
+        mutex_init(&instance->adsl_state_serialize);
+
         instance->rcv_buf = (u8 *) __get_free_page(GFP_KERNEL);
         if (!instance->rcv_buf) {
                 dbg("cxacru_bind: no memory for rcv_buf");
@@ -909,6 +1114,7 @@ static void cxacru_unbind(struct usbatm_data *usbatm_instance,
                 struct usb_interface *intf)
 {
         struct cxacru_data *instance = usbatm_instance->driver_data;
+        int is_polling = 1;
 
         dbg("cxacru_unbind entered");
 
@@ -917,8 +1123,20 @@ static void cxacru_unbind(struct usbatm_data *usbatm_instance,
                 return;
         }
 
-        while (!cancel_delayed_work(&instance->poll_work))
-               flush_scheduled_work();
+        mutex_lock(&instance->poll_state_serialize);
+        BUG_ON(instance->poll_state == CXPOLL_SHUTDOWN);
+
+        /* ensure that status polling continues unless
+         * it has already stopped */
+        if (instance->poll_state == CXPOLL_STOPPED)
+                is_polling = 0;
+
+        /* stop polling from being stopped or started */
+        instance->poll_state = CXPOLL_SHUTDOWN;
+        mutex_unlock(&instance->poll_state_serialize);
+
+        if (is_polling)
+                cancel_rearming_delayed_work(&instance->poll_work);
 
         usb_kill_urb(instance->snd_urb);
         usb_kill_urb(instance->rcv_urb);