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MIPS: Alchemy: move calc_clock function.

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Now that nothing in time.c depends on calc_clock, it can
be moved to clocks.c where it belongs.
While at it, give it a better non-generic name and call it
as soon as possible in plat_mem_init.

Signed-off-by: Manuel Lauss <mano@roarinelk.homelinux.net>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
This commit is contained in:
Manuel Lauss
2008-12-21 09:26:24 +01:00
committed by Ralf Baechle
parent 0c694de12b
commit 2699cdfb76
4 changed files with 64 additions and 54 deletions
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54
arch/mips/alchemy/common/clocks.c
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@@ -27,11 +27,21 @@
*/
#include <linux/module.h>
#include <linux/spinlock.h>
#include <asm/time.h>
#include <asm/mach-au1x00/au1000.h>
/*
* I haven't found anyone that doesn't use a 12 MHz source clock,
* but just in case.....
*/
#define AU1000_SRC_CLK 12000000
static unsigned int au1x00_clock; /* Hz */
static unsigned long uart_baud_base;
static DEFINE_SPINLOCK(time_lock);
/*
* Set the au1000_clock
*/
@@ -60,3 +70,47 @@ void set_au1x00_uart_baud_base(unsigned long new_baud_base)
{
uart_baud_base = new_baud_base;
}
/*
* We read the real processor speed from the PLL. This is important
* because it is more accurate than computing it from the 32 KHz
* counter, if it exists. If we don't have an accurate processor
* speed, all of the peripherals that derive their clocks based on
* this advertised speed will introduce error and sometimes not work
* properly. This function is futher convoluted to still allow configurations
* to do that in case they have really, really old silicon with a
* write-only PLL register. -- Dan
*/
unsigned long au1xxx_calc_clock(void)
{
unsigned long cpu_speed;
unsigned long flags;
spin_lock_irqsave(&time_lock, flags);
/*
* On early Au1000, sys_cpupll was write-only. Since these
* silicon versions of Au1000 are not sold by AMD, we don't bend
* over backwards trying to determine the frequency.
*/
if (au1xxx_cpu_has_pll_wo())
#ifdef CONFIG_SOC_AU1000_FREQUENCY
cpu_speed = CONFIG_SOC_AU1000_FREQUENCY;
#else
cpu_speed = 396000000;
#endif
else
cpu_speed = (au_readl(SYS_CPUPLL) & 0x0000003f) * AU1000_SRC_CLK;
/* On Alchemy CPU:counter ratio is 1:1 */
mips_hpt_frequency = cpu_speed;
/* Equation: Baudrate = CPU / (SD * 2 * CLKDIV * 16) */
set_au1x00_uart_baud_base(cpu_speed / (2 * ((int)(au_readl(SYS_POWERCTRL)
& 0x03) + 2) * 16));
spin_unlock_irqrestore(&time_lock, flags);
set_au1x00_speed(cpu_speed);
return cpu_speed;
}