diff options
author | Arjan van de Ven <arjan@linux.intel.com> | 2008-10-17 09:20:26 -0700 |
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committer | Arjan van de Ven <arjan@linux.intel.com> | 2008-10-17 09:20:26 -0700 |
commit | 651dab4264e4ba0e563f5ff56f748127246e9065 (patch) | |
tree | 016630974bdcb00fe529b673f96d389e0fd6dc94 /arch/mips/alchemy/common/time.c | |
parent | 40b8606253552109815786e5d4b0de98782d31f5 (diff) | |
parent | 2e532d68a2b3e2aa6b19731501222069735c741c (diff) |
Merge commit 'linus/master' into merge-linus
Conflicts:
arch/x86/kvm/i8254.c
Diffstat (limited to 'arch/mips/alchemy/common/time.c')
-rw-r--r-- | arch/mips/alchemy/common/time.c | 266 |
1 files changed, 266 insertions, 0 deletions
diff --git a/arch/mips/alchemy/common/time.c b/arch/mips/alchemy/common/time.c new file mode 100644 index 00000000000..563d9390a87 --- /dev/null +++ b/arch/mips/alchemy/common/time.c @@ -0,0 +1,266 @@ +/* + * + * Copyright (C) 2001, 2006, 2008 MontaVista Software, <source@mvista.com> + * Copied and modified Carsten Langgaard's time.c + * + * Carsten Langgaard, carstenl@mips.com + * Copyright (C) 1999,2000 MIPS Technologies, Inc. All rights reserved. + * + * ######################################################################## + * + * This program is free software; you can distribute it and/or modify it + * under the terms of the GNU General Public License (Version 2) as + * published by the Free Software Foundation. + * + * This program is distributed in the hope it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License + * for more details. + * + * You should have received a copy of the GNU General Public License along + * with this program; if not, write to the Free Software Foundation, Inc., + * 59 Temple Place - Suite 330, Boston MA 02111-1307, USA. + * + * ######################################################################## + * + * Setting up the clock on the MIPS boards. + * + * We provide the clock interrupt processing and the timer offset compute + * functions. If CONFIG_PM is selected, we also ensure the 32KHz timer is + * available. -- Dan + */ + +#include <linux/types.h> +#include <linux/init.h> +#include <linux/spinlock.h> + +#include <asm/mipsregs.h> +#include <asm/time.h> +#include <asm/mach-au1x00/au1000.h> + +static int no_au1xxx_32khz; +extern int allow_au1k_wait; /* default off for CP0 Counter */ + +#ifdef CONFIG_PM +#if HZ < 100 || HZ > 1000 +#error "unsupported HZ value! Must be in [100,1000]" +#endif +#define MATCH20_INC (328 * 100 / HZ) /* magic number 328 is for HZ=100... */ +static unsigned long last_pc0, last_match20; +#endif + +static DEFINE_SPINLOCK(time_lock); + +unsigned long wtimer; + +#ifdef CONFIG_PM +static irqreturn_t counter0_irq(int irq, void *dev_id) +{ + unsigned long pc0; + int time_elapsed; + static int jiffie_drift; + + if (au_readl(SYS_COUNTER_CNTRL) & SYS_CNTRL_M20) { + /* should never happen! */ + printk(KERN_WARNING "counter 0 w status error\n"); + return IRQ_NONE; + } + + pc0 = au_readl(SYS_TOYREAD); + if (pc0 < last_match20) + /* counter overflowed */ + time_elapsed = (0xffffffff - last_match20) + pc0; + else + time_elapsed = pc0 - last_match20; + + while (time_elapsed > 0) { + do_timer(1); +#ifndef CONFIG_SMP + update_process_times(user_mode(get_irq_regs())); +#endif + time_elapsed -= MATCH20_INC; + last_match20 += MATCH20_INC; + jiffie_drift++; + } + + last_pc0 = pc0; + au_writel(last_match20 + MATCH20_INC, SYS_TOYMATCH2); + au_sync(); + + /* + * Our counter ticks at 10.009765625 ms/tick, we we're running + * almost 10 uS too slow per tick. + */ + + if (jiffie_drift >= 999) { + jiffie_drift -= 999; + do_timer(1); /* increment jiffies by one */ +#ifndef CONFIG_SMP + update_process_times(user_mode(get_irq_regs())); +#endif + } + + return IRQ_HANDLED; +} + +struct irqaction counter0_action = { + .handler = counter0_irq, + .flags = IRQF_DISABLED, + .name = "alchemy-toy", + .dev_id = NULL, +}; + +/* When we wakeup from sleep, we have to "catch up" on all of the + * timer ticks we have missed. + */ +void wakeup_counter0_adjust(void) +{ + unsigned long pc0; + int time_elapsed; + + pc0 = au_readl(SYS_TOYREAD); + if (pc0 < last_match20) + /* counter overflowed */ + time_elapsed = (0xffffffff - last_match20) + pc0; + else + time_elapsed = pc0 - last_match20; + + while (time_elapsed > 0) { + time_elapsed -= MATCH20_INC; + last_match20 += MATCH20_INC; + } + + last_pc0 = pc0; + au_writel(last_match20 + MATCH20_INC, SYS_TOYMATCH2); + au_sync(); + +} + +/* This is just for debugging to set the timer for a sleep delay. */ +void wakeup_counter0_set(int ticks) +{ + unsigned long pc0; + + pc0 = au_readl(SYS_TOYREAD); + last_pc0 = pc0; + au_writel(last_match20 + (MATCH20_INC * ticks), SYS_TOYMATCH2); + au_sync(); +} +#endif + +/* + * I haven't found anyone that doesn't use a 12 MHz source clock, + * but just in case..... + */ +#define AU1000_SRC_CLK 12000000 + +/* + * 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, that we need the 32 KHz when power management + * "wait" is enabled, and we need to detect if the 32 KHz isn't present + * but requested......got it? :-) -- Dan + */ +unsigned long calc_clock(void) +{ + unsigned long cpu_speed; + unsigned long flags; + unsigned long counter; + + spin_lock_irqsave(&time_lock, flags); + + /* Power management cares if we don't have a 32 KHz counter. */ + no_au1xxx_32khz = 0; + counter = au_readl(SYS_COUNTER_CNTRL); + if (counter & SYS_CNTRL_E0) { + int trim_divide = 16; + + au_writel(counter | SYS_CNTRL_EN1, SYS_COUNTER_CNTRL); + + while (au_readl(SYS_COUNTER_CNTRL) & SYS_CNTRL_T1S); + /* RTC now ticks at 32.768/16 kHz */ + au_writel(trim_divide - 1, SYS_RTCTRIM); + while (au_readl(SYS_COUNTER_CNTRL) & SYS_CNTRL_T1S); + + while (au_readl(SYS_COUNTER_CNTRL) & SYS_CNTRL_C1S); + au_writel(0, SYS_TOYWRITE); + while (au_readl(SYS_COUNTER_CNTRL) & SYS_CNTRL_C1S); + } else + no_au1xxx_32khz = 1; + + /* + * 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 (cur_cpu_spec[0]->cpu_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); + return cpu_speed; +} + +void __init plat_time_init(void) +{ + unsigned int est_freq = calc_clock(); + + est_freq += 5000; /* round */ + est_freq -= est_freq%10000; + printk(KERN_INFO "CPU frequency %u.%02u MHz\n", + est_freq / 1000000, ((est_freq % 1000000) * 100) / 1000000); + set_au1x00_speed(est_freq); + set_au1x00_lcd_clock(); /* program the LCD clock */ + +#ifdef CONFIG_PM + /* + * setup counter 0, since it keeps ticking after a + * 'wait' instruction has been executed. The CP0 timer and + * counter 1 do NOT continue running after 'wait' + * + * It's too early to call request_irq() here, so we handle + * counter 0 interrupt as a special irq and it doesn't show + * up under /proc/interrupts. + * + * Check to ensure we really have a 32 KHz oscillator before + * we do this. + */ + if (no_au1xxx_32khz) + printk(KERN_WARNING "WARNING: no 32KHz clock found.\n"); + else { + while (au_readl(SYS_COUNTER_CNTRL) & SYS_CNTRL_C0S); + au_writel(0, SYS_TOYWRITE); + while (au_readl(SYS_COUNTER_CNTRL) & SYS_CNTRL_C0S); + + au_writel(au_readl(SYS_WAKEMSK) | (1 << 8), SYS_WAKEMSK); + au_writel(~0, SYS_WAKESRC); + au_sync(); + while (au_readl(SYS_COUNTER_CNTRL) & SYS_CNTRL_M20); + + /* Setup match20 to interrupt once every HZ */ + last_pc0 = last_match20 = au_readl(SYS_TOYREAD); + au_writel(last_match20 + MATCH20_INC, SYS_TOYMATCH2); + au_sync(); + while (au_readl(SYS_COUNTER_CNTRL) & SYS_CNTRL_M20); + setup_irq(AU1000_TOY_MATCH2_INT, &counter0_action); + + /* We can use the real 'wait' instruction. */ + allow_au1k_wait = 1; + } + +#endif +} |