From 3298fbd5b27eb1ef8c333d03e37b5cb5a78fb25e Mon Sep 17 00:00:00 2001 From: kib Date: Fri, 5 Apr 2019 18:09:22 +0000 Subject: [PATCH] Provide newbus infrastructure for initiating device reset. The methods BUS_RESET_PREPARE(), BUS_RESET(), and BUS_RESET_POST() should be implemented by bus which can provide reset to a device. The methods are described in inline doxygen comments. Code only provides BUS_RESET_PREPARE() and BUS_RESET_POST() helpers instead of default implementation, because actual bus needs to handle device state around reset, while helpers provide the other half of typical prepare/post code. Reviewed by: imp (previous version), jhb (previous version) Sponsored by: Mellanox Technologies MFC after: 2 weeks Differential revision: https://reviews.freebsd.org/D19646 --- sys/kern/bus_if.m | 55 +++++++++++++++++++++++++++ sys/kern/subr_bus.c | 90 +++++++++++++++++++++++++++++++++++++++++++++ sys/sys/bus.h | 6 +++ 3 files changed, 151 insertions(+) diff --git a/sys/kern/bus_if.m b/sys/kern/bus_if.m index 501e8f827915..ef47f0fb59b4 100644 --- a/sys/kern/bus_if.m +++ b/sys/kern/bus_if.m @@ -66,6 +66,16 @@ CODE { panic("bus_add_child is not implemented"); } + + static int null_reset_post(device_t bus, device_t dev) + { + return (0); + } + + static int null_reset_prepare(device_t bus, device_t dev) + { + return (0); + } }; /** @@ -848,3 +858,48 @@ METHOD int get_cpus { size_t _setsize; cpuset_t *_cpuset; } DEFAULT bus_generic_get_cpus; + +/** + * @brief Prepares the given child of the bus for reset + * + * Typically bus detaches or suspends children' drivers, and then + * calls this method to save bus-specific information, for instance, + * PCI config space, which is damaged by reset. + * + * The bus_helper_reset_prepare() helper is provided to ease + * implementing bus reset methods. + * + * @param _dev the bus device + * @param _child the child device + */ +METHOD int reset_prepare { + device_t _dev; + device_t _child; +} DEFAULT null_reset_prepare; + +/** + * @brief Restores the child operations after the reset + * + * The bus_helper_reset_post() helper is provided to ease + * implementing bus reset methods. + * + * @param _dev the bus device + * @param _child the child device + */ +METHOD int reset_post { + device_t _dev; + device_t _child; +} DEFAULT null_reset_post; + +/** + * @brief Performs reset of the child + * + * @param _dev the bus device + * @param _child the child device + * @param _flags DEVF_RESET_ flags + */ +METHOD int reset_child { + device_t _dev; + device_t _child; + int _flags; +}; diff --git a/sys/kern/subr_bus.c b/sys/kern/subr_bus.c index ba177f7895b3..6c82f6de0644 100644 --- a/sys/kern/subr_bus.c +++ b/sys/kern/subr_bus.c @@ -3864,6 +3864,96 @@ bus_generic_resume(device_t dev) return (0); } + +/** + * @brief Helper function for implementing BUS_RESET_POST + * + * Bus can use this function to implement common operations of + * re-attaching or resuming the children after the bus itself was + * reset, and after restoring bus-unique state of children. + * + * @param dev The bus + * #param flags DEVF_RESET_* + */ +int +bus_helper_reset_post(device_t dev, int flags) +{ + device_t child; + int error, error1; + + error = 0; + TAILQ_FOREACH(child, &dev->children,link) { + BUS_RESET_POST(dev, child); + error1 = (flags & DEVF_RESET_DETACH) != 0 ? + device_probe_and_attach(child) : + BUS_RESUME_CHILD(dev, child); + if (error == 0 && error1 != 0) + error = error1; + } + return (error); +} + +static void +bus_helper_reset_prepare_rollback(device_t dev, device_t child, int flags) +{ + + child = TAILQ_NEXT(child, link); + if (child == NULL) + return; + TAILQ_FOREACH_FROM(child, &dev->children,link) { + BUS_RESET_POST(dev, child); + if ((flags & DEVF_RESET_DETACH) != 0) + device_probe_and_attach(child); + else + BUS_RESUME_CHILD(dev, child); + } +} + +/** + * @brief Helper function for implementing BUS_RESET_PREPARE + * + * Bus can use this function to implement common operations of + * detaching or suspending the children before the bus itself is + * reset, and then save bus-unique state of children that must + * persists around reset. + * + * @param dev The bus + * #param flags DEVF_RESET_* + */ +int +bus_helper_reset_prepare(device_t dev, int flags) +{ + device_t child; + int error; + + if (dev->state != DS_ATTACHED) + return (EBUSY); + + TAILQ_FOREACH_REVERSE(child, &dev->children, device_list, link) { + if ((flags & DEVF_RESET_DETACH) != 0) { + error = device_get_state(child) == DS_ATTACHED ? + device_detach(child) : 0; + } else { + error = BUS_SUSPEND_CHILD(dev, child); + } + if (error == 0) { + error = BUS_RESET_PREPARE(dev, child); + if (error != 0) { + if ((flags & DEVF_RESET_DETACH) != 0) + device_probe_and_attach(child); + else + BUS_RESUME_CHILD(dev, child); + } + } + if (error != 0) { + bus_helper_reset_prepare_rollback(dev, child, flags); + return (error); + } + } + return (0); +} + + /** * @brief Helper function for implementing BUS_PRINT_CHILD(). * diff --git a/sys/sys/bus.h b/sys/sys/bus.h index 4ad4231a9512..a9fc2387eccf 100644 --- a/sys/sys/bus.h +++ b/sys/sys/bus.h @@ -143,6 +143,10 @@ struct devreq { /* Flags for DEV_DELETE. */ #define DEVF_FORCE_DELETE 0x0000001 +/* Flags for DEV_RESET */ +#define DEVF_RESET_DETACH 0x0000001 /* Detach drivers vs suspend + device */ + #ifdef _KERNEL #include @@ -494,6 +498,8 @@ int bus_generic_unmap_resource(device_t dev, device_t child, int type, struct resource_map *map); int bus_generic_write_ivar(device_t dev, device_t child, int which, uintptr_t value); +int bus_helper_reset_post(device_t dev, int flags); +int bus_helper_reset_prepare(device_t dev, int flags); int bus_null_rescan(device_t dev); /*