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Commit 55f49f26 authored by Nathaniel McCallum's avatar Nathaniel McCallum Committed by Greg Kroah-Hartman
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USB: handle bcd incrementation in usb modalias generation 



This patch fixes a bug when incrementing/decrementing on a BCD formatted
integer (i.e. 0x09++ should be 0x10 not 0x0A).  It just adds a function
for incrementing/decrementing BCD integers by converting to decimal,
doing the increment/decrement and then converting back to BCD.

Signed-off-by: default avatarNathaniel McCallum <nathaniel@natemccallum.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent afe2dab4

scripts/mod/file2alias.c

+47 −2
Original line number Diff line number Diff line
@@ -160,6 +160,45 @@ static void do_usb_entry(struct usb_device_id *id, 
		   "MODULE_ALIAS(\"%s\");\n", alias);

}



/* Handles increment/decrement of BCD formatted integers */

/* Returns the previous value, so it works like i++ or i-- */

static unsigned int incbcd(unsigned int *bcd,

			   int inc,

			   unsigned char max,

			   size_t chars)

{

	unsigned int init = *bcd, i, j;

	unsigned long long c, dec = 0;



	/* If bcd is not in BCD format, just increment */

	if (max > 0x9) {

		*bcd += inc;

		return init;

	}



	/* Convert BCD to Decimal */

	for (i=0 ; i < chars ; i++) {

		c = (*bcd >> (i << 2)) & 0xf;

		c = c > 9 ? 9 : c; /* force to bcd just in case */

		for (j=0 ; j < i ; j++)

			c = c * 10;

		dec += c;

	}



	/* Do our increment/decrement */

	dec += inc;

	*bcd  = 0;



	/* Convert back to BCD */

	for (i=0 ; i < chars ; i++) {

		for (c=1,j=0 ; j < i ; j++)

			c = c * 10;

		c = (dec / c) % 10;

		*bcd += c << (i << 2);

	}

	return init;

}



static void do_usb_entry_multi(struct usb_device_id *id, struct module *mod)

{

	unsigned int devlo, devhi;
@@ -208,10 +247,16 @@ static void do_usb_entry_multi(struct usb_device_id *id, struct module *mod) 
		}



		if (clo > 0x0)

			do_usb_entry(id, devlo++, ndigits, clo, max, max, mod);

			do_usb_entry(id,

				     incbcd(&devlo, 1, max,

					    sizeof(id->bcdDevice_lo) * 2),

				     ndigits, clo, max, max, mod);



		if (chi < max)

			do_usb_entry(id, devhi--, ndigits, 0x0, chi, max, mod);

			do_usb_entry(id,

				     incbcd(&devhi, -1, max,

					    sizeof(id->bcdDevice_lo) * 2),

				     ndigits, 0x0, chi, max, mod);

	}

}