linux/drivers/watchdog/booke_wdt.c
Bhumika Goyal b893e344bf watchdog: constify watchdog_ops structures
Declare watchdog_ops structures as const as they are only stored in the
ops field of a watchdog_device structure. This field is of type const, so
watchdog_ops structures having this property can be made const too.
Done using Coccinelle:

@r disable optional_qualifier@
identifier x;
position p;
@@
static struct watchdog_ops x@p={...};

@ok@
struct watchdog_device w;
identifier r.x;
position p;
@@
w.ops=&x@p;

@bad@
position p != {r.p,ok.p};
identifier r.x;
@@
x@p

@depends on !bad disable optional_qualifier@
identifier r.x;
@@
+const
struct watchdog_ops x;

File size details before and after patching.
First line of every .o file shows the file size before patching
and second line shows the size after patching.

   text    data     bss     dec     hex filename

   1340	    544	      0	   1884	    75c	drivers/watchdog/bcm_kona_wdt.o
   1436	    440	      0	   1876	    754	drivers/watchdog/bcm_kona_wdt.o

   1176	    544	      4	   1724	    6bc	drivers/watchdog/digicolor_wdt.o
   1272	    440	      4	   1716	    6b4	drivers/watchdog/digicolor_wdt.o

    925	    580	     89	   1594	    63a	drivers/watchdog/ep93xx_wdt.o
   1021	    476	     89	   1586	    632	drivers/watchdog/ep93xx_wdt.o

   4932	    288	     17	   5237	   1475	drivers/watchdog/s3c2410_wdt.o
   5028	    192	     17	   5237	   1475	drivers/watchdog/s3c2410_wdt.o

   1977	    292	      1	   2270	    8de	drivers/watchdog/sama5d4_wdt.o
   2073	    196	      1	   2270	    8de	drivers/watchdog/sama5d4_wdt.o

   1375	    484	      1	   1860	    744	drivers/watchdog/sirfsoc_wdt.o
   1471	    380	      1	   1852	    73c	drivers/watchdog/sirfsoc_wdt.o

Size remains the same for the files drivers/watchdog/diag288_wdt.o
drivers/watchdog/asm9260_wdt.o and drivers/watchdog/atlas7_wdt.o

The following .o files did not compile:
drivers/watchdog/sun4v_wdt.o, drivers/watchdog/sbsa_gwdt.o,
drivers/watchdog/rt2880_wdt.o, drivers/watchdog/booke_wdt.o
drivers/watchdog/mt7621_wdt.o

Signed-off-by: Bhumika Goyal <bhumirks@gmail.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2017-02-24 14:00:23 -08:00

244 lines
5.9 KiB
C

/*
* Watchdog timer for PowerPC Book-E systems
*
* Author: Matthew McClintock
* Maintainer: Kumar Gala <galak@kernel.crashing.org>
*
* Copyright 2005, 2008, 2010-2011 Freescale Semiconductor Inc.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/module.h>
#include <linux/smp.h>
#include <linux/watchdog.h>
#include <asm/reg_booke.h>
#include <asm/time.h>
#include <asm/div64.h>
/* If the kernel parameter wdt=1, the watchdog will be enabled at boot.
* Also, the wdt_period sets the watchdog timer period timeout.
* For E500 cpus the wdt_period sets which bit changing from 0->1 will
* trigger a watchog timeout. This watchdog timeout will occur 3 times, the
* first time nothing will happen, the second time a watchdog exception will
* occur, and the final time the board will reset.
*/
#ifdef CONFIG_PPC_FSL_BOOK3E
#define WDTP(x) ((((x)&0x3)<<30)|(((x)&0x3c)<<15))
#define WDTP_MASK (WDTP(0x3f))
#else
#define WDTP(x) (TCR_WP(x))
#define WDTP_MASK (TCR_WP_MASK)
#endif
static bool booke_wdt_enabled;
module_param(booke_wdt_enabled, bool, 0);
static int booke_wdt_period = CONFIG_BOOKE_WDT_DEFAULT_TIMEOUT;
module_param(booke_wdt_period, int, 0);
#ifdef CONFIG_PPC_FSL_BOOK3E
/* For the specified period, determine the number of seconds
* corresponding to the reset time. There will be a watchdog
* exception at approximately 3/5 of this time.
*
* The formula to calculate this is given by:
* 2.5 * (2^(63-period+1)) / timebase_freq
*
* In order to simplify things, we assume that period is
* at least 1. This will still result in a very long timeout.
*/
static unsigned long long period_to_sec(unsigned int period)
{
unsigned long long tmp = 1ULL << (64 - period);
unsigned long tmp2 = ppc_tb_freq;
/* tmp may be a very large number and we don't want to overflow,
* so divide the timebase freq instead of multiplying tmp
*/
tmp2 = tmp2 / 5 * 2;
do_div(tmp, tmp2);
return tmp;
}
/*
* This procedure will find the highest period which will give a timeout
* greater than the one required. e.g. for a bus speed of 66666666 and
* and a parameter of 2 secs, then this procedure will return a value of 38.
*/
static unsigned int sec_to_period(unsigned int secs)
{
unsigned int period;
for (period = 63; period > 0; period--) {
if (period_to_sec(period) >= secs)
return period;
}
return 0;
}
#define MAX_WDT_TIMEOUT period_to_sec(1)
#else /* CONFIG_PPC_FSL_BOOK3E */
static unsigned long long period_to_sec(unsigned int period)
{
return period;
}
static unsigned int sec_to_period(unsigned int secs)
{
return secs;
}
#define MAX_WDT_TIMEOUT 3 /* from Kconfig */
#endif /* !CONFIG_PPC_FSL_BOOK3E */
static void __booke_wdt_set(void *data)
{
u32 val;
struct watchdog_device *wdog = data;
val = mfspr(SPRN_TCR);
val &= ~WDTP_MASK;
val |= WDTP(sec_to_period(wdog->timeout));
mtspr(SPRN_TCR, val);
}
static void booke_wdt_set(void *data)
{
on_each_cpu(__booke_wdt_set, data, 0);
}
static void __booke_wdt_ping(void *data)
{
mtspr(SPRN_TSR, TSR_ENW|TSR_WIS);
}
static int booke_wdt_ping(struct watchdog_device *wdog)
{
on_each_cpu(__booke_wdt_ping, NULL, 0);
return 0;
}
static void __booke_wdt_enable(void *data)
{
u32 val;
struct watchdog_device *wdog = data;
/* clear status before enabling watchdog */
__booke_wdt_ping(NULL);
val = mfspr(SPRN_TCR);
val &= ~WDTP_MASK;
val |= (TCR_WIE|TCR_WRC(WRC_CHIP)|WDTP(sec_to_period(wdog->timeout)));
mtspr(SPRN_TCR, val);
}
/**
* booke_wdt_disable - disable the watchdog on the given CPU
*
* This function is called on each CPU. It disables the watchdog on that CPU.
*
* TCR[WRC] cannot be changed once it has been set to non-zero, but we can
* effectively disable the watchdog by setting its period to the maximum value.
*/
static void __booke_wdt_disable(void *data)
{
u32 val;
val = mfspr(SPRN_TCR);
val &= ~(TCR_WIE | WDTP_MASK);
mtspr(SPRN_TCR, val);
/* clear status to make sure nothing is pending */
__booke_wdt_ping(NULL);
}
static int booke_wdt_start(struct watchdog_device *wdog)
{
on_each_cpu(__booke_wdt_enable, wdog, 0);
pr_debug("watchdog enabled (timeout = %u sec)\n", wdog->timeout);
return 0;
}
static int booke_wdt_stop(struct watchdog_device *wdog)
{
on_each_cpu(__booke_wdt_disable, NULL, 0);
pr_debug("watchdog disabled\n");
return 0;
}
static int booke_wdt_set_timeout(struct watchdog_device *wdt_dev,
unsigned int timeout)
{
wdt_dev->timeout = timeout;
booke_wdt_set(wdt_dev);
return 0;
}
static struct watchdog_info booke_wdt_info __ro_after_init = {
.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
.identity = "PowerPC Book-E Watchdog",
};
static const struct watchdog_ops booke_wdt_ops = {
.owner = THIS_MODULE,
.start = booke_wdt_start,
.stop = booke_wdt_stop,
.ping = booke_wdt_ping,
.set_timeout = booke_wdt_set_timeout,
};
static struct watchdog_device booke_wdt_dev = {
.info = &booke_wdt_info,
.ops = &booke_wdt_ops,
.min_timeout = 1,
};
static void __exit booke_wdt_exit(void)
{
watchdog_unregister_device(&booke_wdt_dev);
}
static int __init booke_wdt_init(void)
{
int ret = 0;
bool nowayout = WATCHDOG_NOWAYOUT;
pr_info("powerpc book-e watchdog driver loaded\n");
booke_wdt_info.firmware_version = cur_cpu_spec->pvr_value;
booke_wdt_set_timeout(&booke_wdt_dev,
period_to_sec(booke_wdt_period));
watchdog_set_nowayout(&booke_wdt_dev, nowayout);
booke_wdt_dev.max_timeout = MAX_WDT_TIMEOUT;
if (booke_wdt_enabled)
booke_wdt_start(&booke_wdt_dev);
ret = watchdog_register_device(&booke_wdt_dev);
return ret;
}
module_init(booke_wdt_init);
module_exit(booke_wdt_exit);
MODULE_ALIAS("booke_wdt");
MODULE_DESCRIPTION("PowerPC Book-E watchdog driver");
MODULE_LICENSE("GPL");