From: Albert Lee Date: Tue, 3 Jul 2007 20:28:36 +0000 (+0200) Subject: ide: pdc202xx_new PLL input clock fix X-Git-Tag: v2.6.22~33^2~1 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=8006bf56e360a4db71d304df778870a371a9e930;p=linux-2.6 ide: pdc202xx_new PLL input clock fix Recently the PLL input clock of Promise 2027x is sometimes detected higher than expected (e.g. 20.027 MHz compared to 16.714 MHz). It seems sometimes the mdelay() function is not as precise as it used to be. Per Alan's advice, HT or power management might affect the precision of mdelay(). This patch calls gettimeofday() to measure the time elapsed and calculate the PLL input clock accordingly. Signed-off-by: Albert Lee Cc: Alan Cox Cc: Bahadir Balban Acked-by: Sergei Shtylyov Signed-off-by: Bartlomiej Zolnierkiewicz --- diff --git a/drivers/ide/pci/pdc202xx_new.c b/drivers/ide/pci/pdc202xx_new.c index cc0bfdcf1f..0765dce694 100644 --- a/drivers/ide/pci/pdc202xx_new.c +++ b/drivers/ide/pci/pdc202xx_new.c @@ -306,11 +306,13 @@ static long __devinit read_counter(u32 dma_base) */ static long __devinit detect_pll_input_clock(unsigned long dma_base) { + struct timeval start_time, end_time; long start_count, end_count; - long pll_input; + long pll_input, usec_elapsed; u8 scr1; start_count = read_counter(dma_base); + do_gettimeofday(&start_time); /* Start the test mode */ outb(0x01, dma_base + 0x01); @@ -322,6 +324,7 @@ static long __devinit detect_pll_input_clock(unsigned long dma_base) mdelay(10); end_count = read_counter(dma_base); + do_gettimeofday(&end_time); /* Stop the test mode */ outb(0x01, dma_base + 0x01); @@ -333,7 +336,10 @@ static long __devinit detect_pll_input_clock(unsigned long dma_base) * Calculate the input clock in Hz * (the clock counter is 30 bit wide and counts down) */ - pll_input = ((start_count - end_count) & 0x3ffffff) * 100; + usec_elapsed = (end_time.tv_sec - start_time.tv_sec) * 1000000 + + (end_time.tv_usec - start_time.tv_usec); + pll_input = ((start_count - end_count) & 0x3ffffff) / 10 * + (10000000 / usec_elapsed); DBG("start[%ld] end[%ld]\n", start_count, end_count);