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fsi: Prevent multiple concurrent rescans

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The bus scanning process isn't terribly good at parallel attempts
at rescanning the same bus. Let's have a per-master mutex protecting
the scanning process.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This commit is contained in:
Benjamin Herrenschmidt 2018-06-21 18:00:05 +10:00
parent d1dcd67825
commit 9840fcd8cc
2 changed files with 16 additions and 2 deletions
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16
drivers/fsi/fsi-core.c
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@ -1203,8 +1203,14 @@ static void fsi_master_unscan(struct fsi_master *master)
int fsi_master_rescan(struct fsi_master *master)
{
int rc;
mutex_lock(&master->scan_lock);
fsi_master_unscan(master);
return fsi_master_scan(master);
rc = fsi_master_scan(master);
mutex_unlock(&master->scan_lock);
return rc;
}
EXPORT_SYMBOL_GPL(fsi_master_rescan);
@ -1240,6 +1246,7 @@ int fsi_master_register(struct fsi_master *master)
int rc;
struct device_node *np;
mutex_init(&master->scan_lock);
master->idx = ida_simple_get(&master_ida, 0, INT_MAX, GFP_KERNEL);
dev_set_name(&master->dev, "fsi%d", master->idx);
@ -1264,8 +1271,11 @@ int fsi_master_register(struct fsi_master *master)
}
np = dev_of_node(&master->dev);
if (!of_property_read_bool(np, "no-scan-on-init"))
if (!of_property_read_bool(np, "no-scan-on-init")) {
mutex_lock(&master->scan_lock);
fsi_master_scan(master);
mutex_unlock(&master->scan_lock);
}
return 0;
}
@ -1278,7 +1288,9 @@ void fsi_master_unregister(struct fsi_master *master)
master->idx = -1;
}
mutex_lock(&master->scan_lock);
fsi_master_unscan(master);
mutex_unlock(&master->scan_lock);
device_unregister(&master->dev);
}
EXPORT_SYMBOL_GPL(fsi_master_unregister);

2
drivers/fsi/fsi-master.h
View File

@ -18,6 +18,7 @@
#define DRIVERS_FSI_MASTER_H
#include <linux/device.h>
#include <linux/mutex.h>
/* Various protocol delays */
#define FSI_ECHO_DELAY_CLOCKS 16 /* Number clocks for echo delay */
@ -59,6 +60,7 @@ struct fsi_master {
int idx;
int n_links;
int flags;
struct mutex scan_lock;
int (*read)(struct fsi_master *, int link, uint8_t id,
uint32_t addr, void *val, size_t size);
int (*write)(struct fsi_master *, int link, uint8_t id,