• Heiko Carstens's avatar
    [S390] Reset infrastructure for re-IPL. · 15e9b586
    Heiko Carstens authored
    In case of re-IPL and diag308 doesn't work we have to reset all devices
    manually and wait synchronously that each reset finished.
    This patch adds the necessary infrastucture and the first exploiter of it.
    Subsystems that need to add a function that needs to be called at re-IPL
    may register/unregister this function via
    struct reset_call {
    	struct reset_call *next;
    	void (*fn)(void);
    void register_reset_call(struct reset_call *reset);
    void unregister_reset_call(struct reset_call *reset);
    When the registered function get called the context is:
    - all cpus beside the current one are stopped
    - all machine checks and interrupts are disabled
    - prefixing is disabled
    - a default machine check handler is available for use
    The registered functions may not take any locks are sleep.
    For the common I/O layer part of this patch:
    Introduce a reset_call css_reset that does the following:
    - clear all subchannels
    - perform a rchp on all channel paths and wait for the resulting
      machine checks
    This replaces the calls to clear_all_subchannels() and
    cio_reset_channel_paths() for kexec and ccw reipl. reipl_ccw_dev() now
    uses reipl_find_schid() to determine the subchannel id for a given
    device id.
    Also remove cio_reset_channel_paths() and friends since they are not
    needed anymore.
    Signed-off-by: default avatarHeiko Carstens <heiko.carstens@de.ibm.com>
    Signed-off-by: default avatarCornelia Huck <cornelia.huck@de.ibm.com>
    Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>