[U-Boot] PATCH mtd CFI flash: timeout calculation underflow if imprecise 1kHz timer: fix

[Renato Andreola]

 From 341dbd88695d3514699aae612d640ed93feb8821 Mon Sep 17 00:00:00 2001
From: Renato Andreola <renato.andreola at imagos.it>
Date: Thu, 6 Aug 2009 18:05:00 +0200
Subject: [PATCH] drivers/mtd/cfi_flash: precision and underflow problem in tout calculation

With old configuration it could happen tout=0 if CONFIG_SYS_HZ<1000
solved avoiding the preprocessor conditional and introducing a compile time branch between a high freq case and a slow freq case.

Signed-off-by: Alessandro Rubini <rubini at gnudd.com> Renato Andreola <renato.andreola at imagos.it>
---
  drivers/mtd/cfi_flash.c |    7 ++++---
  1 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/mtd/cfi_flash.c b/drivers/mtd/cfi_flash.c
index 81ac5d3..499044f 100644
--- a/drivers/mtd/cfi_flash.c
+++ b/drivers/mtd/cfi_flash.c
@@ -659,9 +659,10 @@ static int flash_status_check (flash_info_t * info, flash_sect_t sector,
  {
  	ulong start;

-#if CONFIG_SYS_HZ != 1000
-	tout *= CONFIG_SYS_HZ/1000;
-#endif
+        if (CONFIG_SYS_HZ > 10000)
+		tout *= CONFIG_SYS_HZ/1000;  /* for a big HZ, avoid overflow */
+        else
+		tout = (tout * CONFIG_SYS_HZ) / 1000 + 1;

  	/* Wait for command completion */
  	start = get_timer (0);
-- 
1.5.5