hi,

i'm trying to do a forward port of the out of tree patches for the kwikbyte kb9202b. my board is booting and detects the nand flash, but only in certain circumstances.

the hwcontrol function looks like this:

#define KB9202_NAND_NCE ((unsigned int)1 << 28) /* EN* on D28 */

static void kb9202_nand_hwcontrol(struct mtd_info *mtd, int cmd, unsigned int ctrl) { ...

if (ctrl & NAND_NCE) AT91C_BASE_PIOB->PIO_CODR = KB9202_NAND_NCE; else AT91C_BASE_PIOB->PIO_SODR = KB9202_NAND_NCE;

... }

the problem is that for some reason the enable signal isn't generated when using the pre-processor constant KB9202_NAND_NCE. on the other hand it is generated when using ((unsigned int)1 << 28), instead of the define. it took me some hours to figure this out ...

the generated assembler code differs slightly:

[without define]

Dump of assembler code for function kb9202_nand_hwcontrol: 0x21f1998c <kb9202_nand_hwcontrol+0>: tst r2, #128 ; 0x80 0x21f19990 <kb9202_nand_hwcontrol+4>: ldr r0, [r0, #152] 0x21f19994 <kb9202_nand_hwcontrol+8>: beq 0x21f199d0 <kb9202_nand_hwcontrol+68> 0x21f19998 <kb9202_nand_hwcontrol+12>: ldr r3, [r0, #4] 0x21f1999c <kb9202_nand_hwcontrol+16>: tst r2, #2 ; 0x2 0x21f199a0 <kb9202_nand_hwcontrol+20>: bic r3, r3, #6291456; 0x600000 0x21f199a4 <kb9202_nand_hwcontrol+24>: orrne r3, r3, #2097152; 0x200000 0x21f199a8 <kb9202_nand_hwcontrol+28>: tst r2, #4 ; 0x4 0x21f199ac <kb9202_nand_hwcontrol+32>: orrne r3, r3, #4194304; 0x400000 0x21f199b0 <kb9202_nand_hwcontrol+36>: tst r2, #1 ; 0x1 0x21f199b4 <kb9202_nand_hwcontrol+40>: str r3, [r0, #4]

0x21f199b8 <kb9202_nand_hwcontrol+44>: movne r2, #268435456 ; 0x10000000 0x21f199bc <kb9202_nand_hwcontrol+48>: mvnne r3, #1792 ; 0x700 0x21f199c0 <kb9202_nand_hwcontrol+52>: moveq r2, #268435456 ; 0x10000000 0x21f199c4 <kb9202_nand_hwcontrol+56>: mvneq r3, #1792 ; 0x700

0x21f199c8 <kb9202_nand_hwcontrol+60>: strne r2, [r3, #-203] 0x21f199cc <kb9202_nand_hwcontrol+64>: streq r2, [r3, #-207] 0x21f199d0 <kb9202_nand_hwcontrol+68>: cmn r1, #1 ; 0x1 0x21f199d4 <kb9202_nand_hwcontrol+72>: ldrne r2, [r0, #4] 0x21f199d8 <kb9202_nand_hwcontrol+76>: andne r3, r1, #255 ; 0xff 0x21f199dc <kb9202_nand_hwcontrol+80>: strneb r3, [r2] 0x21f199e0 <kb9202_nand_hwcontrol+84>: mov pc, lr

[differences with define]

0x21f199b8 <kb9202_nand_hwcontrol+44>: movne r2, #268435456 ; 0x10000000 0x21f199bc <kb9202_nand_hwcontrol+48>: mvnne r3, #2304 ; 0x900 0x21f199c0 <kb9202_nand_hwcontrol+52>: moveq r2, #268435456 ; 0x10000000 0x21f199c4 <kb9202_nand_hwcontrol+56>: mvneq r3, #2304 ; 0x900

any idea what could be the problem? some kind of compiler optimization i guess, though i expected the two expressions to be 100% equivalent.

-- Matthias Kaehlcke Embedded Linux Engineer Barcelona

An ounce of practice is worth more than tons of preaching (Mahatma Gandhi) .''`. using free software / Debian GNU/Linux | http://debian.org : :' : `. `'` gpg --keyserver pgp.mit.edu --recv-keys 47D8E5D4 `-