From f0d1b0b30d250a07627ad8b9fbbb5c7cc08422e8 Mon Sep 17 00:00:00 2001 From: David Howells Date: Fri, 8 Dec 2006 02:37:49 -0800 Subject: [PATCH] LOG2: Implement a general integer log2 facility in the kernel This facility provides three entry points: ilog2() Log base 2 of unsigned long ilog2_u32() Log base 2 of u32 ilog2_u64() Log base 2 of u64 These facilities can either be used inside functions on dynamic data: int do_something(long q) { ...; y = ilog2(x) ...; } Or can be used to statically initialise global variables with constant values: unsigned n = ilog2(27); When performing static initialisation, the compiler will report "error: initializer element is not constant" if asked to take a log of zero or of something not reducible to a constant. They treat negative numbers as unsigned. When not dealing with a constant, they fall back to using fls() which permits them to use arch-specific log calculation instructions - such as BSR on x86/x86_64 or SCAN on FRV - if available. [akpm@osdl.org: MMC fix] Signed-off-by: David Howells Cc: Benjamin Herrenschmidt Cc: Paul Mackerras Cc: Herbert Xu Cc: David Howells Cc: Wojtek Kaniewski Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/mmc/tifm_sd.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/mmc/tifm_sd.c') diff --git a/drivers/mmc/tifm_sd.c b/drivers/mmc/tifm_sd.c index e846499a004..f18ad998b3c 100644 --- a/drivers/mmc/tifm_sd.c +++ b/drivers/mmc/tifm_sd.c @@ -387,7 +387,7 @@ static void tifm_sd_prepare_data(struct tifm_sd *card, struct mmc_command *cmd) writel(TIFM_FIFO_INT_SETALL, sock->addr + SOCK_DMA_FIFO_INT_ENABLE_CLEAR); - writel(long_log2(cmd->data->blksz) - 2, + writel(ilog2(cmd->data->blksz) - 2, sock->addr + SOCK_FIFO_PAGE_SIZE); writel(TIFM_FIFO_ENABLE, sock->addr + SOCK_FIFO_CONTROL); writel(TIFM_FIFO_INTMASK, sock->addr + SOCK_DMA_FIFO_INT_ENABLE_SET); -- cgit v1.2.3