Blackfin arch: use do_div() for the 64bit division as pointed out by Bernd

If you need a 64 bit divide in the kernel, use asm/div64.h.
Revert the addition of udivdi3.

Cc: Bernd Schmidt <bernd.schmidt@analog.com>
Signed-off-by: Mike Frysinger <michael.frysinger@analog.com>
Signed-off-by: Bryan Wu <bryan.wu@analog.com>

3 files changed, 8 insertions, 378 deletions

diff --git a/arch/blackfin/kernel/setup.c b/arch/blackfin/kernel/setup.c
index dfe06b09a9d4..eee5a1fcb64c 100644
--- a/arch/blackfin/kernel/setup.c
+++ b/arch/blackfin/kernel/setup.c
@@ -43,6 +43,7 @@
 #include <asm/cacheflush.h>
 #include <asm/blackfin.h>
 #include <asm/cplbinit.h>
+#include <asm/div64.h>
 #include <asm/fixed_code.h>
 #include <asm/early_printk.h>
 
@@ -504,13 +505,17 @@ EXPORT_SYMBOL(get_sclk);
 
 unsigned long sclk_to_usecs(unsigned long sclk)
 {
-	return (USEC_PER_SEC * (u64)sclk) / get_sclk();
+	u64 tmp = USEC_PER_SEC * (u64)sclk;
+	do_div(tmp, get_sclk());
+	return tmp;
 }
 EXPORT_SYMBOL(sclk_to_usecs);
 
 unsigned long usecs_to_sclk(unsigned long usecs)
 {
-	return (get_sclk() * (u64)usecs) / USEC_PER_SEC;
+	u64 tmp = get_sclk() * (u64)usecs;
+	do_div(tmp, USEC_PER_SEC);
+	return tmp;
 }
 EXPORT_SYMBOL(usecs_to_sclk);
 
diff --git a/arch/blackfin/lib/Makefile b/arch/blackfin/lib/Makefile
index bfdad52c570b..635288fc5f54 100644
--- a/arch/blackfin/lib/Makefile
+++ b/arch/blackfin/lib/Makefile
@@ -4,7 +4,7 @@
 
 lib-y := \
 	ashldi3.o ashrdi3.o lshrdi3.o \
-	muldi3.o divsi3.o udivsi3.o udivdi3.o modsi3.o umodsi3.o \
+	muldi3.o divsi3.o udivsi3.o modsi3.o umodsi3.o \
 	checksum.o memcpy.o memset.o memcmp.o memchr.o memmove.o \
 	strcmp.o strcpy.o strncmp.o strncpy.o \
 	umulsi3_highpart.o smulsi3_highpart.o \
diff --git a/arch/blackfin/lib/udivdi3.S b/arch/blackfin/lib/udivdi3.S
deleted file mode 100644
index ad1ebee675e1..000000000000
--- a/arch/blackfin/lib/udivdi3.S
+++ /dev/null
@@ -1,375 +0,0 @@
-/*
- * udivdi3.S - unsigned long long division
- *
- * Copyright 2003-2007 Analog Devices Inc.
- * Enter bugs at http://blackfin.uclinux.org/
- *
- * Licensed under the GPLv2 or later.
- */
-
-#include <linux/linkage.h>
-
-#define CARRY AC0
-
-#ifdef CONFIG_ARITHMETIC_OPS_L1
-.section .l1.text
-#else
-.text
-#endif
-
-
-ENTRY(___udivdi3)
-   R3 = [SP + 12];
-   [--SP] = (R7:4, P5:3);
-
-   /* Attempt to use divide primitive first; these will handle
-   **  most cases, and they're quick - avoids stalls incurred by
-   ** testing for identities.
-   */
-
-   R4 = R2 | R3;
-   CC = R4 == 0;
-   IF CC JUMP .LDIV_BY_ZERO;
-
-   R4.H = 0x8000;
-   R4 >>>= 16;                  // R4 now 0xFFFF8000
-   R5 = R0 | R2;                // If either dividend or
-   R4 = R5 & R4;                // divisor have bits in
-   CC = R4;                     // top half or low half's sign
-   IF CC JUMP .LIDENTS;          // bit, skip builtins.
-   R4 = R1 | R3;                // Also check top halves
-   CC = R4;
-   IF CC JUMP .LIDENTS;
-
-   /* Can use the builtins. */
-
-   AQ = CC;                     // Clear AQ (CC==0)
-   DIVQ(R0, R2);
-   DIVQ(R0, R2);
-   DIVQ(R0, R2);
-   DIVQ(R0, R2);
-   DIVQ(R0, R2);
-   DIVQ(R0, R2);
-   DIVQ(R0, R2);
-   DIVQ(R0, R2);
-   DIVQ(R0, R2);
-   DIVQ(R0, R2);
-   DIVQ(R0, R2);
-   DIVQ(R0, R2);
-   DIVQ(R0, R2);
-   DIVQ(R0, R2);
-   DIVQ(R0, R2);
-   DIVQ(R0, R2);
-   DIVQ(R0, R2);
-   R0 = R0.L (Z);
-   R1 = 0;
-   (R7:4, P5:3) = [SP++];
-   RTS;
-
-.LIDENTS:
-   /* Test for common identities. Value to be returned is
-   ** placed in R6,R7.
-   */
-                                // Check for 0/y, return 0
-   R4 = R0 | R1;
-   CC = R4 == 0;
-   IF CC JUMP .LRETURN_R0;
-
-                                // Check for x/x, return 1
-   R6 = R0 - R2;                // If x == y, then both R6 and R7 will be zero
-   R7 = R1 - R3;
-   R4 = R6 | R7;                // making R4 zero.
-   R6 += 1;                     // which would now make R6:R7==1.
-   CC = R4 == 0;
-   IF CC JUMP .LRETURN_IDENT;
-
-                                // Check for x/1, return x
-   R6 = R0;
-   R7 = R1;
-   CC = R3 == 0;
-   IF !CC JUMP .Lnexttest;
-   CC = R2 == 1;
-   IF CC JUMP .LRETURN_IDENT;
-
-.Lnexttest:
-   R4.L = ONES R2;              // check for div by power of two which
-   R5.L = ONES R3;              // can be done using a shift
-   R6 = PACK (R5.L, R4.L);
-   CC = R6 == 1;
-   IF CC JUMP .Lpower_of_two_upper_zero;
-   R6 = PACK (R4.L, R5.L);
-   CC = R6 == 1;
-   IF CC JUMP .Lpower_of_two_lower_zero;
-
-                                // Check for x < y, return 0
-   R6 = 0;
-   R7 = R6;
-   CC = R1 < R3 (IU);
-   IF CC JUMP .LRETURN_IDENT;
-   CC = R1 == R3;
-   IF !CC JUMP .Lno_idents;
-   CC = R0 < R2 (IU);
-   IF CC JUMP .LRETURN_IDENT;
-
-.Lno_idents:                    // Idents don't match. Go for the full operation
-
-
-   // If X, or X and Y have high bit set, it'll affect the
-   // results, so shift right one to stop this. Note: we've already
-   // checked that X >= Y, so Y's msb won't be set unless X's
-   // is.
-
-   R4 = 0;
-   CC = R1 < 0;
-   IF !CC JUMP .Lx_msb_clear;
-   CC = !CC;                   // 1 -> 0;
-   R1 = ROT R1 BY -1;          // Shift X >> 1
-   R0 = ROT R0 BY -1;          // lsb -> CC
-   BITSET(R4,31);              // to record only x msb was set
-   CC = R3 < 0;
-   IF !CC JUMP .Ly_msb_clear;
-   CC = !CC;
-   R3 = ROT R3 BY -1;          // Shift Y >> 1
-   R2 = ROT R2 BY -1;
-   BITCLR(R4,31);              // clear bit to record only x msb was set
-
-.Ly_msb_clear:
-.Lx_msb_clear:
-   // Bit 31 in R4 indicates X msb set, but Y msb wasn't, and no bits
-   // were lost, so we should shift result left by one.
-
-   [--SP] = R4;                // save for later
-
-   // In the loop that follows, each iteration we add
-   // either Y' or -Y' to the Remainder. We compute the
-   // negated Y', and store, for convenience. Y' goes
-   // into P0:P1, while -Y' goes into P2:P3.
-
-   P0 = R2;
-   P1 = R3;
-   R2 = -R2;
-   CC = CARRY;
-   CC = !CC;
-   R4 = CC;
-   R3 = -R3;
-   R3 = R3 - R4;
-
-   R6 = 0;                     // remainder = 0
-   R7 = R6;
-
-   [--SP] = R2; P2 = SP;
-   [--SP] = R3; P3 = SP;
-   [--SP] = R6; P5 = SP;       // AQ = 0
-   [--SP] = P1;
-
-   /* In the loop that follows, we use the following
-   ** register assignments:
-   ** R0,R1 X, workspace
-   ** R2,R3 Y, workspace
-   ** R4,R5 partial Div
-   ** R6,R7 partial remainder
-   ** P5 AQ
-   ** The remainder and div form a 128-bit number, with
-   ** the remainder in the high 64-bits.
-   */
-   R4 = R0;                    // Div = X'
-   R5 = R1;
-   R3 = 0;
-
-   P4 = 64;                    // Iterate once per bit
-   LSETUP(.LULST,.LULEND) LC0 = P4;
-.LULST:
-        /* Shift Div and remainder up by one. The bit shifted
-        ** out of the top of the quotient is shifted into the bottom
-        ** of the remainder.
-        */
-        CC = R3;
-        R4 = ROT R4 BY 1;
-        R5 = ROT R5 BY 1 ||        // low q to high q
-             R2 = [P5];            // load saved AQ
-        R6 = ROT R6 BY 1 ||        // high q to low r
-             R0 = [P2];            // load -Y'
-        R7 = ROT R7 BY 1 ||        // low r to high r
-             R1 = [P3];
-
-                                   // Assume add -Y'
-        CC = R2 < 0;               // But if AQ is set...
-        IF CC R0 = P0;             // then add Y' instead
-        IF CC R1 = P1;
-
-        R6 = R6 + R0;              // Rem += (Y' or -Y')
-        CC = CARRY;
-        R0 = CC;
-        R7 = R7 + R1;
-        R7 = R7 + R0 (NS) ||
-             R1 = [SP];
-                                   // Set the next AQ bit
-        R1 = R7 ^ R1;              // from Remainder and Y'
-        R1 = R1 >> 31 ||           // Negate AQ's value, and
-             [P5] = R1;            // save next AQ
-        BITTGL(R1, 0);             // add neg AQ  to the Div
-.LULEND: R4 = R4 + R1;
-
-   R6 = [SP + 16];
-
-   R0 = R4;
-   R1 = R5;
-   CC = BITTST(R6,30);         // Just set CC=0
-   R4 = ROT R0 BY 1;           // but if we had to shift X,
-   R5 = ROT R1 BY 1;           // and didn't shift any bits out,
-   CC = BITTST(R6,31);         // then the result will be half as
-   IF CC R0 = R4;              // much as required, so shift left
-   IF CC R1 = R5;              // one space.
-
-   SP += 20;
-   (R7:4, P5:3) = [SP++];
-   RTS;
-
-.Lpower_of_two:
-   /* Y has a single bit set, which means it's a power of two.
-   ** That means we can perform the division just by shifting
-   ** X to the right the appropriate number of bits
-   */
-
-   /* signbits returns the number of sign bits, minus one.
-   ** 1=>30, 2=>29, ..., 0x40000000=>0. Which means we need
-   ** to shift right n-signbits spaces. It also means 0x80000000
-   ** is a special case, because that *also* gives a signbits of 0
-   */
-.Lpower_of_two_lower_zero:
-   R7 = 0;
-   R6 = R1 >> 31;
-   CC = R3 < 0;
-   IF CC JUMP .LRETURN_IDENT;
-
-   R2.L = SIGNBITS R3;
-   R2 = R2.L (Z);
-   R2 += -62;
-   (R7:4, P5:3) = [SP++];
-   JUMP ___lshftli;
-
-.Lpower_of_two_upper_zero:
-   CC = R2 < 0;
-   IF CC JUMP .Lmaxint_shift;
-
-   R2.L = SIGNBITS R2;
-   R2 = R2.L (Z);
-   R2 += -30;
-   (R7:4, P5:3) = [SP++];
-   JUMP ___lshftli;
-
-.Lmaxint_shift:
-   R2 = -31;
-   (R7:4, P5:3) = [SP++];
-   JUMP ___lshftli;
-
-.LRETURN_IDENT:
-   R0 = R6;
-   R1 = R7;
-.LRETURN_R0:
-   (R7:4, P5:3) = [SP++];
-   RTS;
-.LDIV_BY_ZERO:
-   R0 = ~R2;
-   R1 = R0;
-   (R7:4, P5:3) = [SP++];
-   RTS;
-
-ENDPROC(___udivdi3)
-
-
-ENTRY(___lshftli)
-	CC = R2 == 0;
-	IF CC JUMP .Lfinished;	// nothing to do
-	CC = R2 < 0;
-	IF CC JUMP .Lrshift;
-	R3 = 64;
-	CC = R2 < R3;
-	IF !CC JUMP .Lretzero;
-
-	// We're shifting left, and it's less than 64 bits, so
-	// a valid result will be returned.
-
-	R3 >>= 1;	// R3 now 32
-	CC = R2 < R3;
-
-	IF !CC JUMP .Lzerohalf;
-
-	// We're shifting left, between 1 and 31 bits, which means
-	// some of the low half will be shifted into the high half.
-	// Work out how much.
-
-	R3 = R3 - R2;
-
-	// Save that much data from the bottom half.
-
-	P1 = R7;
-	R7 = R0;
-	R7 >>= R3;
-
-	// Adjust both parts of the parameter.
-
-	R0 <<= R2;
-	R1 <<= R2;
-
-	// And include the bits moved across.
-
-	R1 = R1 | R7;
-	R7 = P1;
-	RTS;
-
-.Lzerohalf:
-	// We're shifting left, between 32 and 63 bits, so the
-	// bottom half will become zero, and the top half will
-	// lose some bits. How many?
-
-	R2 = R2 - R3;	// N - 32
-	R1 = LSHIFT R0 BY R2.L;
-	R0 = R0 - R0;
-	RTS;
-
-.Lretzero:
-	R0 = R0 - R0;
-	R1 = R0;
-.Lfinished:
-	RTS;
-
-.Lrshift:
-	// We're shifting right, but by how much?
-	R2 = -R2;
-	R3 = 64;
-	CC = R2 < R3;
-	IF !CC JUMP .Lretzero;
-
-	// Shifting right less than 64 bits, so some result bits will
-	// be retained.
-
-	R3 >>= 1;	// R3 now 32
-	CC = R2 < R3;
-	IF !CC JUMP .Lsignhalf;
-
-	// Shifting right between 1 and 31 bits, so need to copy
-	// data across words.
-
-	P1 = R7;
-	R3 = R3 - R2;
-	R7 = R1;
-	R7 <<= R3;
-	R1 >>= R2;
-	R0 >>= R2;
-	R0 = R7 | R0;
-	R7 = P1;
-	RTS;
-
-.Lsignhalf:
-	// Shifting right between 32 and 63 bits, so the top half
-	// will become all zero-bits, and the bottom half is some
-	// of the top half. But how much?
-
-	R2 = R2 - R3;
-	R0 = R1;
-	R0 >>= R2;
-	R1 = 0;
-	RTS;
-
-ENDPROC(___lshftli)