NAME
config_intrhook — schedule a function to be run after interrupts have been enabled, but before root is mountedSYNOPSIS
#include <sys/kernel.h> typedef void (*ich_func_t)(void *arg); intconfig_intrhook_establish(struct intr_config_hook *hook); void
config_intrhook_disestablish(struct intr_config_hook *hook); void
config_intrhook_oneshot(ich_func_t func, void *arg);
DESCRIPTION
The config_intrhook_establish() function schedules a function to be run after interrupts have been enabled, but before root is mounted. If the system has already passed this point in its initialization, the function is called immediately. The config_intrhook_disestablish() function removes the entry from the hook queue. The config_intrhook_oneshot() function schedules a function to be run as described for config_intrhook_establish(); the entry is automatically removed from the hook queue after that function runs. This is appropriate when additional device configuration must be done after interrupts are enabled, but there is no need to stall the boot process after that. This function allocates memory using M_WAITOK; do not call this while holding any non-sleepable locks. Before root is mounted, all the previously established hooks are run. The boot process is then stalled until all handlers remove their hook from the hook queue with config_intrhook_disestablish(). The boot process then proceeds to attempt to mount the root file system. Any driver that can potentially provide devices they wish to be mounted as root must use either this hook, or probe all these devices in the initial probe. Since interrupts are disabled during the probe process, many drivers need a method to probe for devices with interrupts enabled. The requests are made with the intr_config_hook structure. This structure is defined as follows:
struct intr_config_hook {
TAILQ_ENTRY(intr_config_hook) ich_links;/* Private */
ich_func_t ich_func; /* function to call */
void *ich_arg; /* Argument to call */
};
RETURN VALUES
A zero return value means the hook was successfully added to the queue (with either deferred or immediate execution). A non-zero return value means the hook could not be added to the queue because it was already on the queue.SEE ALSO
DEVICE_ATTACH(9)HISTORY
These functions were introduced in FreeBSD 3.0 with the CAM subsystem, but are available for any driver to use.AUTHORS
The functions were written by Justin Gibbs <[email protected]>. This manual page was written by M. Warner Losh <[email protected]>.| August 10, 2017 | Debian |