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e0c24bddf0
Once we call fsi_master_unregister, the core will put_device, potentially freeing the hub master. This change adds a comment explaining the lifetime of an allocated fsi_master. We then add a reference from the driver to the hub master, so it stays around until we've finished ->remove(). Signed-off-by: Jeremy Kerr <jk@ozlabs.org> Tested-by: Christopher Bostic <cbostic@linux.vnet.ibm.com> Signed-off-by: Joel Stanley <joel@jms.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
60 lines
2.2 KiB
C
60 lines
2.2 KiB
C
/*
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* FSI master definitions. These comprise the core <--> master interface,
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* to allow the core to interact with the (hardware-specific) masters.
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*
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* Copyright (C) IBM Corporation 2016
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*/
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#ifndef DRIVERS_FSI_MASTER_H
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#define DRIVERS_FSI_MASTER_H
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#include <linux/device.h>
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#define FSI_MASTER_FLAG_SWCLOCK 0x1
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struct fsi_master {
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struct device dev;
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int idx;
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int n_links;
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int flags;
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int (*read)(struct fsi_master *, int link, uint8_t id,
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uint32_t addr, void *val, size_t size);
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int (*write)(struct fsi_master *, int link, uint8_t id,
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uint32_t addr, const void *val, size_t size);
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int (*term)(struct fsi_master *, int link, uint8_t id);
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int (*send_break)(struct fsi_master *, int link);
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int (*link_enable)(struct fsi_master *, int link);
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};
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#define dev_to_fsi_master(d) container_of(d, struct fsi_master, dev)
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/**
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* fsi_master registration & lifetime: the fsi_master_register() and
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* fsi_master_unregister() functions will take ownership of the master, and
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* ->dev in particular. The registration path performs a get_device(), which
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* takes the first reference on the device. Similarly, the unregistration path
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* performs a put_device(), which may well drop the last reference.
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*
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* This means that master implementations *may* need to hold their own
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* reference (via get_device()) on master->dev. In particular, if the device's
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* ->release callback frees the fsi_master, then fsi_master_unregister will
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* invoke this free if no other reference is held.
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*
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* The same applies for the error path of fsi_master_register; if the call
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* fails, dev->release will have been invoked.
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*/
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extern int fsi_master_register(struct fsi_master *master);
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extern void fsi_master_unregister(struct fsi_master *master);
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extern int fsi_master_rescan(struct fsi_master *master);
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#endif /* DRIVERS_FSI_MASTER_H */
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