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    Subject[PATCH -v3] watchdog, SP5100: Check if firmware has set correct value in tcobase.

    Stefano found SP5100 TCO watchdog driver using wrong address.

    [ 9.148536] SP5100 TCO timer: SP5100 TCO WatchDog Timer Driver v0.01
    [ 9.148628] DEBUG __ioremap_caller WARNING address=b8fe00 size=8 valid=1 reserved=1

    and e820 said that range is RAM.

    We should check if we can use that reading out. BIOS could just program wrong address there.

    -v2: Mike pointed out one path need one release.
    -v3: corrected logic checking with request_mem_region_exclusive()
    Found by Konrad.


    Reported-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
    Signed-off-by:Yinghai Lu <yinghai@kernel.org>
    Acked-by: Mike Waychison <mikew@google.com>
    Tested-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

    ---
    drivers/watchdog/sp5100_tco.c | 14 ++++++++++++--
    1 file changed, 12 insertions(+), 2 deletions(-)

    Index: linux-2.6/drivers/watchdog/sp5100_tco.c
    ===================================================================
    --- linux-2.6.orig/drivers/watchdog/sp5100_tco.c
    +++ linux-2.6/drivers/watchdog/sp5100_tco.c
    @@ -42,6 +42,7 @@
    #define PFX TCO_MODULE_NAME ": "

    /* internal variables */
    +static u32 tcobase_phys;
    static void __iomem *tcobase;
    static unsigned int pm_iobase;
    static DEFINE_SPINLOCK(tco_lock); /* Guards the hardware */
    @@ -305,10 +306,16 @@ static unsigned char __devinit sp5100_tc
    /* Low three bits of BASE0 are reserved. */
    val = val << 8 | (inb(SP5100_IO_PM_DATA_REG) & 0xf8);

    + if (!request_mem_region_exclusive(val, SP5100_WDT_MEM_MAP_SIZE, "SP5100 TCO")) {
    + printk(KERN_ERR PFX "mmio address 0x%04x already in use\n", val);
    + goto unreg_region;
    + }
    + tcobase_phys = val;
    +
    tcobase = ioremap(val, SP5100_WDT_MEM_MAP_SIZE);
    if (tcobase == 0) {
    printk(KERN_ERR PFX "failed to get tcobase address\n");
    - goto unreg_region;
    + goto unreg_mem_region;
    }

    /* Enable watchdog decode bit */
    @@ -346,7 +353,8 @@ static unsigned char __devinit sp5100_tc
    /* Done */
    return 1;

    - iounmap(tcobase);
    +unreg_mem_region:
    + release_mem_region(tcobase_phys, SP5100_WDT_MEM_MAP_SIZE);
    unreg_region:
    release_region(pm_iobase, SP5100_PM_IOPORTS_SIZE);
    exit:
    @@ -401,6 +409,7 @@ static int __devinit sp5100_tco_init(str

    exit:
    iounmap(tcobase);
    + release_mem_region(tcobase_phys, SP5100_WDT_MEM_MAP_SIZE);
    release_region(pm_iobase, SP5100_PM_IOPORTS_SIZE);
    return ret;
    }
    @@ -414,6 +423,7 @@ static void __devexit sp5100_tco_cleanup
    /* Deregister */
    misc_deregister(&sp5100_tco_miscdev);
    iounmap(tcobase);
    + release_mem_region(tcobase_phys, SP5100_WDT_MEM_MAP_SIZE);
    release_region(pm_iobase, SP5100_PM_IOPORTS_SIZE);
    }


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