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watchdog: sp5100_tco: Remove code that may cause a boot failure
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A problem was found on PC's with the SB700 chipset: The PC fails to
load BIOS after running the 3.8.x kernel until the power is completely
cut off. It occurs in all 3.8.x versions and the mainline version as of
2/4. The issue does not occur with the 3.7.x builds.

There are two methods for accessing the watchdog registers.

 1. Re-programming a resource address obtained by allocate_resource()
to chipset.
 2. Use the direct memory-mapped IO access.

The method 1 can be used by all the chipsets (SP5100, SB7x0, SB8x0 or
later). However, experience shows that only PC with the SB8x0 (or
later) chipsets can use the method 2.

This patch removes the method 1, because the critical problem was found.
That's why the watchdog timer was able to be used on SP5100 and SB7x0
chipsets until now.

Link: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1116835
Link: https://lkml.org/lkml/2013/2/14/271

Signed-off-by: Takahisa Tanaka <mc74hc00@gmail.com>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Cc: stable <stable@vger.kernel.org>
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Takahisa Tanaka authored and Wim Van Sebroeck committed Mar 22, 2013
1 parent 9217cbb commit 18e4321
Showing 1 changed file with 6 additions and 120 deletions.
126 changes: 6 additions & 120 deletions drivers/watchdog/sp5100_tco.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -40,24 +40,19 @@
#include "sp5100_tco.h"

/* Module and version information */
#define TCO_VERSION "0.03"
#define TCO_VERSION "0.05"
#define TCO_MODULE_NAME "SP5100 TCO timer"
#define TCO_DRIVER_NAME TCO_MODULE_NAME ", v" TCO_VERSION

/* internal variables */
static u32 tcobase_phys;
static u32 resbase_phys;
static u32 tco_wdt_fired;
static void __iomem *tcobase;
static unsigned int pm_iobase;
static DEFINE_SPINLOCK(tco_lock); /* Guards the hardware */
static unsigned long timer_alive;
static char tco_expect_close;
static struct pci_dev *sp5100_tco_pci;
static struct resource wdt_res = {
.name = "Watchdog Timer",
.flags = IORESOURCE_MEM,
};

/* the watchdog platform device */
static struct platform_device *sp5100_tco_platform_device;
Expand All @@ -75,12 +70,6 @@ module_param(nowayout, bool, 0);
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started."
" (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");

static unsigned int force_addr;
module_param(force_addr, uint, 0);
MODULE_PARM_DESC(force_addr, "Force the use of specified MMIO address."
" ONLY USE THIS PARAMETER IF YOU REALLY KNOW"
" WHAT YOU ARE DOING (default=none)");

/*
* Some TCO specific functions
*/
Expand Down Expand Up @@ -176,39 +165,6 @@ static void tco_timer_enable(void)
}
}

static void tco_timer_disable(void)
{
int val;

if (sp5100_tco_pci->revision >= 0x40) {
/* For SB800 or later */
/* Enable watchdog decode bit and Disable watchdog timer */
outb(SB800_PM_WATCHDOG_CONTROL, SB800_IO_PM_INDEX_REG);
val = inb(SB800_IO_PM_DATA_REG);
val |= SB800_PCI_WATCHDOG_DECODE_EN;
val |= SB800_PM_WATCHDOG_DISABLE;
outb(val, SB800_IO_PM_DATA_REG);
} else {
/* For SP5100 or SB7x0 */
/* Enable watchdog decode bit */
pci_read_config_dword(sp5100_tco_pci,
SP5100_PCI_WATCHDOG_MISC_REG,
&val);

val |= SP5100_PCI_WATCHDOG_DECODE_EN;

pci_write_config_dword(sp5100_tco_pci,
SP5100_PCI_WATCHDOG_MISC_REG,
val);

/* Disable Watchdog timer */
outb(SP5100_PM_WATCHDOG_CONTROL, SP5100_IO_PM_INDEX_REG);
val = inb(SP5100_IO_PM_DATA_REG);
val |= SP5100_PM_WATCHDOG_DISABLE;
outb(val, SP5100_IO_PM_DATA_REG);
}
}

/*
* /dev/watchdog handling
*/
Expand Down Expand Up @@ -361,7 +317,7 @@ static unsigned char sp5100_tco_setupdevice(void)
{
struct pci_dev *dev = NULL;
const char *dev_name = NULL;
u32 val, tmp_val;
u32 val;
u32 index_reg, data_reg, base_addr;

/* Match the PCI device */
Expand Down Expand Up @@ -459,63 +415,8 @@ static unsigned char sp5100_tco_setupdevice(void)
} else
pr_debug("SBResource_MMIO is disabled(0x%04x)\n", val);

/*
* Lastly re-programming the watchdog timer MMIO address,
* This method is a last resort...
*
* Before re-programming, to ensure that the watchdog timer
* is disabled, disable the watchdog timer.
*/
tco_timer_disable();

if (force_addr) {
/*
* Force the use of watchdog timer MMIO address, and aligned to
* 8byte boundary.
*/
force_addr &= ~0x7;
val = force_addr;

pr_info("Force the use of 0x%04x as MMIO address\n", val);
} else {
/*
* Get empty slot into the resource tree for watchdog timer.
*/
if (allocate_resource(&iomem_resource,
&wdt_res,
SP5100_WDT_MEM_MAP_SIZE,
0xf0000000,
0xfffffff8,
0x8,
NULL,
NULL)) {
pr_err("MMIO allocation failed\n");
goto unreg_region;
}

val = resbase_phys = wdt_res.start;
pr_debug("Got 0x%04x from resource tree\n", val);
}

/* Restore to the low three bits */
outb(base_addr+0, index_reg);
tmp_val = val | (inb(data_reg) & 0x7);

/* Re-programming the watchdog timer base address */
outb(base_addr+0, index_reg);
outb((tmp_val >> 0) & 0xff, data_reg);
outb(base_addr+1, index_reg);
outb((tmp_val >> 8) & 0xff, data_reg);
outb(base_addr+2, index_reg);
outb((tmp_val >> 16) & 0xff, data_reg);
outb(base_addr+3, index_reg);
outb((tmp_val >> 24) & 0xff, data_reg);

if (!request_mem_region_exclusive(val, SP5100_WDT_MEM_MAP_SIZE,
dev_name)) {
pr_err("MMIO address 0x%04x already in use\n", val);
goto unreg_resource;
}
pr_notice("failed to find MMIO address, giving up.\n");
goto unreg_region;

setup_wdt:
tcobase_phys = val;
Expand Down Expand Up @@ -555,9 +456,6 @@ static unsigned char sp5100_tco_setupdevice(void)

unreg_mem_region:
release_mem_region(tcobase_phys, SP5100_WDT_MEM_MAP_SIZE);
unreg_resource:
if (resbase_phys)
release_resource(&wdt_res);
unreg_region:
release_region(pm_iobase, SP5100_PM_IOPORTS_SIZE);
exit:
Expand All @@ -567,7 +465,6 @@ static unsigned char sp5100_tco_setupdevice(void)
static int sp5100_tco_init(struct platform_device *dev)
{
int ret;
char addr_str[16];

/*
* Check whether or not the hardware watchdog is there. If found, then
Expand Down Expand Up @@ -599,23 +496,14 @@ static int sp5100_tco_init(struct platform_device *dev)
clear_bit(0, &timer_alive);

/* Show module parameters */
if (force_addr == tcobase_phys)
/* The force_addr is vaild */
sprintf(addr_str, "0x%04x", force_addr);
else
strcpy(addr_str, "none");

pr_info("initialized (0x%p). heartbeat=%d sec (nowayout=%d, "
"force_addr=%s)\n",
tcobase, heartbeat, nowayout, addr_str);
pr_info("initialized (0x%p). heartbeat=%d sec (nowayout=%d)\n",
tcobase, heartbeat, nowayout);

return 0;

exit:
iounmap(tcobase);
release_mem_region(tcobase_phys, SP5100_WDT_MEM_MAP_SIZE);
if (resbase_phys)
release_resource(&wdt_res);
release_region(pm_iobase, SP5100_PM_IOPORTS_SIZE);
return ret;
}
Expand All @@ -630,8 +518,6 @@ static void sp5100_tco_cleanup(void)
misc_deregister(&sp5100_tco_miscdev);
iounmap(tcobase);
release_mem_region(tcobase_phys, SP5100_WDT_MEM_MAP_SIZE);
if (resbase_phys)
release_resource(&wdt_res);
release_region(pm_iobase, SP5100_PM_IOPORTS_SIZE);
}

Expand Down

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