parport_pc superio chip fixes

From: Andrea Arcangeli (andrea_at_novell.com)
Date: 09/30/04

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    Date:	Thu, 30 Sep 2004 08:08:51 +0200
To: Andrew Morton <akpm@osdl.org>, Tim Waugh <twaugh@redhat.com>

    This patch fixes some troubles that somebody reported me with the
    superio chips.

    In short rmmod parport_pc && cat /proc/iomem was good enough for
    crashing the box hard on some machine (and hwscan --printer was doing
    just that). The way the oops triggers is that iomem tries to vsprintf
    the p->name, but the p->name was a static string in the module address
    (now unloaded).

    The reason is that the superio chip scanning leaves up to two persistent
    ranges claimed. But the second (legacy) pass has no way to notice the
    resources are already reclaimed. Plus if the superio->io was different
    than the "io" variable (the range to scan for superio chips) the "io"
    range would generate a leak of the original "io" range too.

    I simply make sure to always release the requested space during the
    superio scan, and I make sure not to istantiate new ranges in the
    p->base that would cause the later parport scan to fail too (plus
    leaving up to leaked resources).

    The previous code that was returning values and was leaving garbage in
    there made no sense to me. My best guess (assuming I didn't misread it ;)
    is that probably somebody added the request_region without realizing
    they're pointing to the very same address that would be requested later
    (and nobody does accesses on those ranges until later, so it was very
    safe to claim it later).

    Disclaimer: I don't have the specs of the winbond and smsc at hand, I
    just guessed what they do from the code (nothing checks superio->io
    except get_superio_dma get_superio_irq, which made the thing enough self
    explainatory to fix it without specs)

    Signed-off-by: Andrea Arcangeli <andrea@novell.com>

    --- sles/drivers/parport/parport_pc.c.~1~ 2004-09-30 05:56:36.000000000 +0200
    +++ sles/drivers/parport/parport_pc.c 2004-09-30 07:54:56.469113152 +0200
    @@ -1194,7 +1194,7 @@ struct parport_operations parport_pc_ops
     
     #ifdef CONFIG_PARPORT_PC_SUPERIO
     /* Super-IO chipset detection, Winbond, SMSC */
    -static int __devinit show_parconfig_smsc37c669(int io, int key)
    +static void __devinit show_parconfig_smsc37c669(int io, int key)
     {
             int cr1,cr4,cra,cr23,cr26,cr27,i=0;
             static const char *modes[]={ "SPP and Bidirectional (PS/2)",
    @@ -1261,26 +1261,17 @@ static int __devinit show_parconfig_smsc
                                             superios[i].io = 0x278;
                                             superios[i].irq = 5;
                             }
    - if (io != superios[i].io) {
    - /* how many bytes? */
    - if (!request_region(superios[i].io, 3, "smsc parport")) {
    - superios[i].io = 0;
    - return 0;
    - }
    - }
                             d=(cr26 &0x0f);
                             if((d==1) || (d==3))
                                     superios[i].dma= d;
                             else
                                     superios[i].dma= PARPORT_DMA_NONE;
    - return 1;
                     }
              }
    - return 0;
     }
     
     
    -static int __devinit show_parconfig_winbond(int io, int key)
    +static void __devinit show_parconfig_winbond(int io, int key)
     {
             int cr30,cr60,cr61,cr70,cr74,crf0,i=0;
             static const char *modes[] = {
    @@ -1336,23 +1327,14 @@ static int __devinit show_parconfig_winb
                             printk(KERN_INFO "Super-IO: too many chips!\n");
                     else {
                             superios[i].io = (cr60<<8)|cr61;
    - if (io != superios[i].io) {
    - /* how many bytes? */
    - if (!request_region(superios[i].io, 3, "winbond parport")) {
    - superios[i].io = 0;
    - return 0;
    - }
    - }
                             superios[i].irq = cr70&0x0f;
                             superios[i].dma = (((cr74 & 0x07) > 3) ?
                                                PARPORT_DMA_NONE : (cr74 & 0x07));
    - return 1;
                     }
             }
    - return 0;
     }
     
    -static int __devinit decode_winbond(int efer, int key, int devid, int devrev, int oldid)
    +static void __devinit decode_winbond(int efer, int key, int devid, int devrev, int oldid)
     {
             const char *type = "unknown";
             int id,progif=2;
    @@ -1360,7 +1342,7 @@ static int __devinit decode_winbond(int
             if (devid == devrev)
                     /* simple heuristics, we happened to read some
                        non-winbond register */
    - return 0;
    + return;
     
             id=(devid<<8) | devrev;
     
    @@ -1385,20 +1367,19 @@ static int __devinit decode_winbond(int
                            efer, key, devid, devrev, oldid, type);
     
             if (progif == 2)
    - return show_parconfig_winbond(efer,key);
    - return 0;
    + show_parconfig_winbond(efer,key);
     }
     
    -static int __devinit decode_smsc(int efer, int key, int devid, int devrev)
    +static void __devinit decode_smsc(int efer, int key, int devid, int devrev)
     {
             const char *type = "unknown";
    - int (*func)(int io, int key);
    + void (*func)(int io, int key);
             int id;
     
             if (devid == devrev)
                     /* simple heuristics, we happened to read some
                        non-smsc register */
    - return 0;
    + return;
     
             func=NULL;
             id=(devid<<8) | devrev;
    @@ -1414,8 +1395,7 @@ static int __devinit decode_smsc(int efe
                            efer, key, devid, devrev, type);
     
             if (func)
    - return func(efer,key);
    - return 0;
    + func(efer,key);
     }
     
     
    @@ -1448,8 +1428,7 @@ static void __devinit winbond_check(int
             if ((x_devid == devid) && (x_devrev == devrev) && (x_oldid == oldid))
                     goto out; /* protection against false positives */
     
    - if (decode_winbond(io,key,devid,devrev,oldid));
    - return;
    + decode_winbond(io,key,devid,devrev,oldid);
     out:
             release_region(io, 3);
     }
    @@ -1482,8 +1461,7 @@ static void __devinit winbond_check2(int
             if ((x_devid == devid) && (x_devrev == devrev) && (x_oldid == oldid))
                     goto out; /* protection against false positives */
     
    - if (decode_winbond(io,key,devid,devrev,oldid))
    - return;
    + decode_winbond(io,key,devid,devrev,oldid);
     out:
             release_region(io, 3);
     }
    @@ -1522,8 +1500,7 @@ static void __devinit smsc_check(int io,
                 (x_oldid == oldid) && (x_rev == rev))
                     goto out; /* protection against false positives */
     
    - if (decode_smsc(io,key,oldid,oldrev))
    - return;
    + decode_smsc(io,key,oldid,oldrev);
     out:
             release_region(io, 3);
     }

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