/* * Watchdog timer driver for the WinSystems EBC-C384 * Copyright (C) 2016 William Breathitt Gray * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License, version 2, as * published by the Free Software Foundation. * * This program is distributed in the hope that it will be useful, but * WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * General Public License for more details. */ #include #include #include #include #include #include #include #include #include #include #include #define MODULE_NAME "ebc-c384_wdt" #define WATCHDOG_TIMEOUT 60 /* * The timeout value in minutes must fit in a single byte when sent to the * watchdog timer; the maximum timeout possible is 15300 (255 * 60) seconds. */ #define WATCHDOG_MAX_TIMEOUT 15300 #define BASE_ADDR 0x564 #define ADDR_EXTENT 5 #define CFG_ADDR (BASE_ADDR + 1) #define PET_ADDR (BASE_ADDR + 2) static bool nowayout = WATCHDOG_NOWAYOUT; module_param(nowayout, bool, 0); MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); static unsigned timeout; module_param(timeout, uint, 0); MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds (default=" __MODULE_STRING(WATCHDOG_TIMEOUT) ")"); static int ebc_c384_wdt_start(struct watchdog_device *wdev) { unsigned t = wdev->timeout; /* resolution is in minutes for timeouts greater than 255 seconds */ if (t > 255) t = DIV_ROUND_UP(t, 60); outb(t, PET_ADDR); return 0; } static int ebc_c384_wdt_stop(struct watchdog_device *wdev) { outb(0x00, PET_ADDR); return 0; } static int ebc_c384_wdt_set_timeout(struct watchdog_device *wdev, unsigned t) { /* resolution is in minutes for timeouts greater than 255 seconds */ if (t > 255) { /* round second resolution up to minute granularity */ wdev->timeout = roundup(t, 60); /* set watchdog timer for minutes */ outb(0x00, CFG_ADDR); } else { wdev->timeout = t; /* set watchdog timer for seconds */ outb(0x80, CFG_ADDR); } return 0; } static const struct watchdog_ops ebc_c384_wdt_ops = { .start = ebc_c384_wdt_start, .stop = ebc_c384_wdt_stop, .set_timeout = ebc_c384_wdt_set_timeout }; static const struct watchdog_info ebc_c384_wdt_info = { .options = WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT, .identity = MODULE_NAME }; static int ebc_c384_wdt_probe(struct device *dev, unsigned int id) { struct watchdog_device *wdd; if (!devm_request_region(dev, BASE_ADDR, ADDR_EXTENT, dev_name(dev))) { dev_err(dev, "Unable to lock port addresses (0x%X-0x%X)\n", BASE_ADDR, BASE_ADDR + ADDR_EXTENT); return -EBUSY; } wdd = devm_kzalloc(dev, sizeof(*wdd), GFP_KERNEL); if (!wdd) return -ENOMEM; wdd->info = &ebc_c384_wdt_info; wdd->ops = &ebc_c384_wdt_ops; wdd->timeout = WATCHDOG_TIMEOUT; wdd->min_timeout = 1; wdd->max_timeout = WATCHDOG_MAX_TIMEOUT; watchdog_set_nowayout(wdd, nowayout); if (watchdog_init_timeout(wdd, timeout, dev)) dev_warn(dev, "Invalid timeout (%u seconds), using default (%u seconds)\n", timeout, WATCHDOG_TIMEOUT); dev_set_drvdata(dev, wdd); return watchdog_register_device(wdd); } static int ebc_c384_wdt_remove(struct device *dev, unsigned int id) { struct watchdog_device *wdd = dev_get_drvdata(dev); watchdog_unregister_device(wdd); return 0; } static struct isa_driver ebc_c384_wdt_driver = { .probe = ebc_c384_wdt_probe, .driver = { .name = MODULE_NAME }, .remove = ebc_c384_wdt_remove }; static int __init ebc_c384_wdt_init(void) { if (!dmi_match(DMI_BOARD_NAME, "EBC-C384 SBC")) return -ENODEV; return isa_register_driver(&ebc_c384_wdt_driver, 1); } static void __exit ebc_c384_wdt_exit(void) { isa_unregister_driver(&ebc_c384_wdt_driver); } module_init(ebc_c384_wdt_init); module_exit(ebc_c384_wdt_exit); MODULE_AUTHOR("William Breathitt Gray "); MODULE_DESCRIPTION("WinSystems EBC-C384 watchdog timer driver"); MODULE_LICENSE("GPL v2"); MODULE_ALIAS("isa:" MODULE_NAME); ss='ctrl'>mode:
authorIago Abal <mail@iagoabal.eu>2017-01-11 14:00:21 +0100
committerVinod Koul <vinod.koul@intel.com>2017-01-25 15:35:11 +0530
commit91539eb1fda2d530d3b268eef542c5414e54bf1a (patch)
tree960f5ca6342ad20837aff18aad6e8ecd7da32fd6 /include/sound/aess.h
parent6610d0edf6dc7ee97e46ab3a538a565c79d26199 (diff)
dmaengine: pl330: fix double lock
The static bug finder EBA (http://www.iagoabal.eu/eba/) reported the following double-lock bug: Double lock: 1. spin_lock_irqsave(pch->lock, flags) at pl330_free_chan_resources:2236; 2. call to function `pl330_release_channel' immediately after; 3. call to function `dma_pl330_rqcb' in line 1753; 4. spin_lock_irqsave(pch->lock, flags) at dma_pl330_rqcb:1505. I have fixed it as suggested by Marek Szyprowski. First, I have replaced `pch->lock' with `pl330->lock' in functions `pl330_alloc_chan_resources' and `pl330_free_chan_resources'. This avoids the double-lock by acquiring a different lock than `dma_pl330_rqcb'. NOTE that, as a result, `pl330_free_chan_resources' executes `list_splice_tail_init' on `pch->work_list' under lock `pl330->lock', whereas in the rest of the code `pch->work_list' is protected by `pch->lock'. I don't know if this may cause race conditions. Similarly `pch->cyclic' is written by `pl330_alloc_chan_resources' under `pl330->lock' but read by `pl330_tx_submit' under `pch->lock'. Second, I have removed locking from `pl330_request_channel' and `pl330_release_channel' functions. Function `pl330_request_channel' is only called from `pl330_alloc_chan_resources', so the lock is already held. Function `pl330_release_channel' is called from `pl330_free_chan_resources', which already holds the lock, and from `pl330_del'. Function `pl330_del' is called in an error path of `pl330_probe' and at the end of `pl330_remove', but I assume that there cannot be concurrent accesses to the protected data at those points. Signed-off-by: Iago Abal <mail@iagoabal.eu> Reviewed-by: Marek Szyprowski <m.szyprowski@samsung.com> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Diffstat (limited to 'include/sound/aess.h')