diff options
Diffstat (limited to 'arch/mips/alchemy/common/clocks.c')
| -rw-r--r-- | arch/mips/alchemy/common/clocks.c | 65 |
1 files changed, 44 insertions, 21 deletions
diff --git a/arch/mips/alchemy/common/clocks.c b/arch/mips/alchemy/common/clocks.c index 043429d17c5..d8991854530 100644 --- a/arch/mips/alchemy/common/clocks.c +++ b/arch/mips/alchemy/common/clocks.c @@ -27,12 +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 int lcd_clock; /* KHz */ static unsigned long uart_baud_base; +static DEFINE_SPINLOCK(time_lock); + /* * Set the au1000_clock */ @@ -63,31 +72,45 @@ void set_au1x00_uart_baud_base(unsigned long new_baud_base) } /* - * Calculate the Au1x00's LCD clock based on the current - * cpu clock and the system bus clock, and try to keep it - * below 40 MHz (the Pb1000 board can lock-up if the LCD - * clock is over 40 MHz). + * 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 */ -void set_au1x00_lcd_clock(void) +unsigned long au1xxx_calc_clock(void) { - unsigned int static_cfg0; - unsigned int sys_busclk = (get_au1x00_speed() / 1000) / - ((int)(au_readl(SYS_POWERCTRL) & 0x03) + 2); + unsigned long cpu_speed; + unsigned long flags; - static_cfg0 = au_readl(MEM_STCFG0); + spin_lock_irqsave(&time_lock, flags); - if (static_cfg0 & (1 << 11)) - lcd_clock = sys_busclk / 5; /* note: BCLK switching fails with D5 */ + /* + * 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 - lcd_clock = sys_busclk / 4; + cpu_speed = (au_readl(SYS_CPUPLL) & 0x0000003f) * AU1000_SRC_CLK; - if (lcd_clock > 50000) /* Epson MAX */ - printk(KERN_WARNING "warning: LCD clock too high (%u KHz)\n", - lcd_clock); -} + /* 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)); -unsigned int get_au1x00_lcd_clock(void) -{ - return lcd_clock; + spin_unlock_irqrestore(&time_lock, flags); + + set_au1x00_speed(cpu_speed); + + return cpu_speed; } -EXPORT_SYMBOL(get_au1x00_lcd_clock); |