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Subject[PATCH] 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: Greg Kroah-Hartman <gregkh@suse.de>
Cc: Duncan Sands <duncan.sands@math.u-psud.fr>
---
This patch requires usb-cxacru-export-detailed-device-info-through-sysfs
from gregkh-2.6.

drivers/usb/atm/cxacru.c | 215 ++++++++++++++++++++++++++++++++++++++++++++--
1 files changed, 206 insertions(+), 9 deletions(-)

diff --git a/drivers/usb/atm/cxacru.c b/drivers/usb/atm/cxacru.c
index c8b69bf..a89c484 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
@@ -145,6 +146,13 @@ enum cxacru_info_idx {
/* dunno what the missing two mean */
CXINF_MAX = 0x1c,
};
+
+enum cxacru_poll_state {
+ CXPOLL_STOPPING,
+ CXPOLL_STOPPED,
+ CXPOLL_POLLING,
+ CXPOLL_SHUTDOWN
+};

struct cxacru_modem_type {
u32 pll_f_clk;
@@ -158,8 +166,11 @@ struct cxacru_data {
const struct cxacru_modem_type *modem_type;

int line_status;
+ 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 +182,18 @@ 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 +206,11 @@ 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 +299,105 @@ 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 = 0;
+ int poll = -1;
+
+ if (!capable(CAP_NET_ADMIN))
+ return -EACCES;
+
+ if (!strcmp(buf, "stop") || !strcmp(buf, "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 = strlen(buf);
+ 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(buf, "restart"))
+ msleep(1500);
+
+ if (!strcmp(buf, "start") || !strcmp(buf, "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 = strlen(buf);
+ poll = CXPOLL_POLLING;
+ }
+ }
+
+ if (!strcmp(buf, "poll")) {
+ ret = strlen(buf);
+ poll = CXPOLL_POLLING;
+ }
+
+ if (!ret)
+ return -EINVAL;
+
+ 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);
+ }
+
+ 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 +432,8 @@ 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 +614,6 @@ 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 +622,7 @@ 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");

@@ -522,7 +642,25 @@ static int cxacru_atm_start(struct usbatm_data *usbatm_instance,
}

/* 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);
+
+ if (start_polling)
+ cxacru_poll_status(&instance->poll_work.work);
return 0;
}

@@ -533,16 +671,46 @@ 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 +765,20 @@ 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,
@@ -834,6 +1014,10 @@ static int cxacru_bind(struct usbatm_data *usbatm_instance,
instance->usbatm = 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;

instance->rcv_buf = (u8 *) __get_free_page(GFP_KERNEL);
if (!instance->rcv_buf) {
@@ -909,6 +1093,7 @@ 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 +1102,20 @@ 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);
--
1.5.0.1
--
Simon Arlott
-
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