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Subject[PATCH 1/3] Add drvctl default device attribute
Date

===================================================================


ChangeSet@1.1961, 2004-11-08 02:03:59-05:00, dtor_core@ameritech.net
Driver core: add "drvctl" default device attribute that allows
userspace request execution of bus-specific actions
for devices. Used to manually control driver and
device binding/unbinding/rebinding, causes execution
of bus->drvctl() helper. Expects commands in form of
"CMD [DRIVER NAME] [ARG ARG...]]".

Serio bus's drvctl rearranged to accept the following
commands: "detach", "attach <driver>", "rescan", and
"reconnect".

Signed-off-by: Dmitry Torokhov <dtor@mail.ru>


drivers/base/interface.c | 74 +++++++++++++++++++++++++++++++++++++++++++-
drivers/input/serio/serio.c | 61 +++++++++++++++++-------------------
include/linux/device.h | 4 +-
3 files changed, 106 insertions(+), 33 deletions(-)


===================================================================



diff -Nru a/drivers/base/interface.c b/drivers/base/interface.c
--- a/drivers/base/interface.c 2004-11-08 02:10:34 -05:00
+++ b/drivers/base/interface.c 2004-11-08 02:10:34 -05:00
@@ -13,6 +13,7 @@
#include <linux/err.h>
#include <linux/stat.h>
#include <linux/string.h>
+#include <linux/ctype.h>

/**
* detach_state - control the default power state for the device.
@@ -42,10 +43,81 @@
return n;
}

-static DEVICE_ATTR(detach_state, 0644, detach_show, detach_store);
+/**
+ * drvctl - controls device and driver binding.
+ *
+ * Writing to the attribute causes execution of bus-specific drvctl()
+ * helper that is used to disconnect device from its driver or rebind
+ * device to a specific driver.
+ * Commands are expected in the following format:
+ * CMD [DRIVER_NAME] [ARG ARG ARG]
+ * drvctl handler is free to mangle the args string.
+ */
+
+#define GET_WORD(x) \
+do { \
+ while (isspace(*args)) args++; \
+ (x) = args; \
+ while (*args && !isspace(*args)) args++; \
+ if (isspace(*args)) { \
+ save_chr = *args; \
+ *args++ = '\0'; \
+ } \
+} while (0) \

+static ssize_t drvctl_store(struct device * dev, const char * buf, size_t count)
+{
+ int retval = -ENOSYS;
+ struct device_driver *drv = NULL;
+ char *str, *action, *drv_name, *args;
+ char save_chr = 0;
+
+ if (!dev->bus->drvctl)
+ return -ENOSYS;
+
+ /* copy buffer so we can mangle it */
+ if (!(args = str = kmalloc(count + 1, GFP_KERNEL)))
+ return -ENOMEM;
+
+ memcpy(str, buf, count);
+ str[count] = '\0';
+
+ GET_WORD(action);
+ GET_WORD(drv_name);
+
+ if (*drv_name) {
+ if (!(drv = driver_find(drv_name, dev->bus))) {
+ /*
+ * if this is not a name of existing driver
+ * merge it with thye rest of the string and
+ * pass to drvctl as 'args'
+ */
+ if (*args)
+ *--args = save_chr;
+ args = drv_name;
+ }
+ }
+
+ while (*args == ' ') args++;
+
+ pr_debug("drvctl - action: '%s', driver: '%s', args: '%s'\n",
+ action, drv ? drv->name : "", args);
+
+ retval = dev->bus->drvctl(dev, action, drv, args);
+
+ if (drv)
+ put_driver(drv);
+ kfree(str);
+
+ return (retval < 0) ? retval : count;
+}
+#undef GET_WORD
+
+static DEVICE_ATTR(detach_state, 0644, detach_show, detach_store);
+static DEVICE_ATTR(drvctl, 0200, NULL, drvctl_store);

struct attribute * dev_default_attrs[] = {
&dev_attr_detach_state.attr,
+ &dev_attr_drvctl.attr,
NULL,
};
diff -Nru a/drivers/input/serio/serio.c b/drivers/input/serio/serio.c
--- a/drivers/input/serio/serio.c 2004-11-08 02:10:34 -05:00
+++ b/drivers/input/serio/serio.c 2004-11-08 02:10:34 -05:00
@@ -246,36 +246,6 @@
return sprintf(buf, "%s\n", serio->name);
}

-static ssize_t serio_rebind_driver(struct device *dev, const char *buf, size_t count)
-{
- struct serio *serio = to_serio_port(dev);
- struct device_driver *drv;
- int retval;
-
- retval = down_interruptible(&serio_sem);
- if (retval)
- return retval;
-
- retval = count;
- if (!strncmp(buf, "none", count)) {
- serio_disconnect_port(serio);
- } else if (!strncmp(buf, "reconnect", count)) {
- serio_reconnect_port(serio);
- } else if (!strncmp(buf, "rescan", count)) {
- serio_disconnect_port(serio);
- serio_connect_port(serio, NULL);
- } else if ((drv = driver_find(buf, &serio_bus)) != NULL) {
- serio_disconnect_port(serio);
- serio_connect_port(serio, to_serio_driver(drv));
- put_driver(drv);
- } else {
- retval = -EINVAL;
- }
-
- up(&serio_sem);
-
- return retval;
-}

static ssize_t serio_show_bind_mode(struct device *dev, char *buf)
{
@@ -302,7 +272,6 @@

static struct device_attribute serio_device_attrs[] = {
__ATTR(description, S_IRUGO, serio_show_description, NULL),
- __ATTR(drvctl, S_IWUSR, NULL, serio_rebind_driver),
__ATTR(bind_mode, S_IWUSR | S_IRUGO, serio_show_bind_mode, serio_set_bind_mode),
__ATTR_NULL
};
@@ -597,6 +566,35 @@
up(&serio_sem);
}

+static int serio_rebind_driver(struct device *dev, const char *action,
+ struct device_driver *drv, char *args)
+{
+ struct serio *serio = to_serio_port(dev);
+ int retval;
+
+ retval = down_interruptible(&serio_sem);
+ if (retval)
+ return retval;
+
+ if (!strcmp(action, "detach")) {
+ serio_disconnect_port(serio);
+ } else if (!strcmp(action, "reconnect")) {
+ serio_reconnect_port(serio);
+ } else if (!strcmp(action, "rescan")) {
+ serio_disconnect_port(serio);
+ serio_connect_port(serio, NULL);
+ } else if (!strcmp(action, "attach") && drv) {
+ serio_disconnect_port(serio);
+ serio_connect_port(serio, to_serio_driver(drv));
+ } else {
+ retval = -EINVAL;
+ }
+
+ up(&serio_sem);
+
+ return retval;
+}
+
static void serio_set_drv(struct serio *serio, struct serio_driver *drv)
{
down(&serio->drv_sem);
@@ -661,6 +659,7 @@

serio_bus.dev_attrs = serio_device_attrs;
serio_bus.drv_attrs = serio_driver_attrs;
+ serio_bus.drvctl = serio_rebind_driver;
bus_register(&serio_bus);

return 0;
diff -Nru a/include/linux/device.h b/include/linux/device.h
--- a/include/linux/device.h 2004-11-08 02:10:34 -05:00
+++ b/include/linux/device.h 2004-11-08 02:10:34 -05:00
@@ -59,7 +59,9 @@
struct driver_attribute * drv_attrs;

int (*match)(struct device * dev, struct device_driver * drv);
- int (*hotplug) (struct device *dev, char **envp,
+ int (*drvctl)(struct device * dev, const char * action,
+ struct device_driver * drv, char * args);
+ int (*hotplug) (struct device *dev, char **envp,
int num_envp, char *buffer, int buffer_size);
int (*suspend)(struct device * dev, u32 state);
int (*resume)(struct device * dev);
-
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