minix/kernel/arch/earm/omap_timer.c
Kees Jongenburger ed45d98dac arm:ensure read_tsc_64 always returns a valid value.
Before this change overflowing the free running clock counter
between the time the timer was read and the time the overflow
check was done resulted in read_tsc_64 returning a to high value.

Change-Id: I1022f271213647f720477c4121d45f0c965456c6
2013-09-27 11:29:04 +02:00

321 lines
8.6 KiB
C

#include "kernel/kernel.h"
#include "kernel/clock.h"
#include <sys/types.h>
#include <machine/cpu.h>
#include <minix/mmio.h>
#include <assert.h>
#include <io.h>
#include <stdlib.h>
#include <stdio.h>
#include "arch_proto.h"
#include "omap_timer.h"
#include "omap_intr.h"
static irq_hook_t omap3_timer_hook; /* interrupt handler hook */
static u64_t high_frc;
struct omap_timer_registers;
struct omap_timer {
vir_bytes base;
int irq_nr;
struct omap_timer_registers *regs;
};
struct omap_timer_registers {
vir_bytes TIDR;
vir_bytes TIOCP_CFG;
vir_bytes TISTAT;
vir_bytes TISR;
vir_bytes TIER;
vir_bytes TWER;
vir_bytes TCLR;
vir_bytes TCRR;
vir_bytes TLDR;
vir_bytes TTGR;
vir_bytes TWPS;
vir_bytes TMAR;
vir_bytes TCAR1;
vir_bytes TSICR;
vir_bytes TCAR2;
vir_bytes TPIR;
vir_bytes TNIR;
vir_bytes TCVR;
vir_bytes TOCR;
vir_bytes TOWR;
};
static struct omap_timer_registers regs_v1 = {
.TIDR = OMAP3_TIMER_TIDR,
.TIOCP_CFG = OMAP3_TIMER_TIOCP_CFG,
.TISTAT = OMAP3_TIMER_TISTAT,
.TISR = OMAP3_TIMER_TISR,
.TIER = OMAP3_TIMER_TIER,
.TWER = OMAP3_TIMER_TWER,
.TCLR = OMAP3_TIMER_TCLR,
.TCRR = OMAP3_TIMER_TCRR,
.TLDR = OMAP3_TIMER_TLDR,
.TTGR = OMAP3_TIMER_TTGR,
.TWPS = OMAP3_TIMER_TWPS,
.TMAR = OMAP3_TIMER_TMAR,
.TCAR1 = OMAP3_TIMER_TCAR1,
.TSICR = OMAP3_TIMER_TSICR,
.TCAR2 = OMAP3_TIMER_TCAR2,
.TPIR = OMAP3_TIMER_TPIR,
.TNIR = OMAP3_TIMER_TNIR,
.TCVR = OMAP3_TIMER_TCVR,
.TOCR = OMAP3_TIMER_TOCR,
.TOWR = OMAP3_TIMER_TOWR,
};
#ifdef DM37XX
static struct omap_timer timer = {
.base = OMAP3_GPTIMER1_BASE,
.irq_nr = OMAP3_GPT1_IRQ,
.regs = &regs_v1
};
/* free running timer */
static struct omap_timer fr_timer = {
.base = OMAP3_GPTIMER10_BASE,
.irq_nr = OMAP3_GPT10_IRQ,
.regs = &regs_v1
};
#endif
#ifdef AM335X
/* AM335X has a different ip block for the non
1ms timers */
static struct omap_timer_registers regs_v2 = {
.TIDR = AM335X_TIMER_TIDR,
.TIOCP_CFG = AM335X_TIMER_TIOCP_CFG,
.TISTAT = AM335X_TIMER_IRQSTATUS_RAW,
.TISR = AM335X_TIMER_IRQSTATUS,
.TIER = AM335X_TIMER_IRQENABLE_SET,
.TWER = AM335X_TIMER_IRQWAKEEN,
.TCLR = AM335X_TIMER_TCLR,
.TCRR = AM335X_TIMER_TCRR,
.TLDR = AM335X_TIMER_TLDR,
.TTGR = AM335X_TIMER_TTGR,
.TWPS = AM335X_TIMER_TWPS,
.TMAR = AM335X_TIMER_TMAR,
.TCAR1 = AM335X_TIMER_TCAR1,
.TSICR = AM335X_TIMER_TSICR,
.TCAR2 = AM335X_TIMER_TCAR2,
.TPIR = -1 , /* UNDEF */
.TNIR = -1 , /* UNDEF */
.TCVR = -1 , /* UNDEF */
.TOCR = -1 , /* UNDEF */
.TOWR = -1 /* UNDEF */
};
/* normal timer */
static struct omap_timer timer = {
.base = AM335X_DMTIMER1_1MS_BASE,
.irq_nr = AM335X_INT_TINT1_1MS,
.regs = &regs_v1
};
/* free running timer */
static struct omap_timer fr_timer = {
.base = AM335X_DMTIMER7_BASE,
.irq_nr = AM335X_INT_TINT7,
.regs = &regs_v2
};
#endif
static int done = 0;
int omap3_register_timer_handler(const irq_handler_t handler)
{
/* Initialize the CLOCK's interrupt hook. */
omap3_timer_hook.proc_nr_e = NONE;
omap3_timer_hook.irq = timer.irq_nr;
put_irq_handler(&omap3_timer_hook, timer.irq_nr, handler);
/* only unmask interrupts after registering */
omap3_irq_unmask(timer.irq_nr);
return 0;
}
/* meta data for remapping */
static kern_phys_map timer_phys_map;
static kern_phys_map fr_timer_phys_map;
void omap3_frclock_init(void)
{
u32_t tisr;
kern_phys_map_ptr(fr_timer.base,ARM_PAGE_SIZE,
&fr_timer_phys_map, (vir_bytes) &fr_timer.base);
/* enable the clock */
#ifdef AM335X
/* Disable the module and wait for the module to be disabled */
set32(CM_PER_TIMER7_CLKCTRL, CM_MODULEMODE_MASK,CM_MODULEMODE_DISABLED);
while( (mmio_read(CM_PER_TIMER7_CLKCTRL) & CM_CLKCTRL_IDLEST) != CM_CLKCTRL_IDLEST_DISABLE);
set32(CLKSEL_TIMER7_CLK,CLKSEL_TIMER7_CLK_SEL_MASK, CLKSEL_TIMER7_CLK_SEL_SEL2);
while( (read32(CLKSEL_TIMER7_CLK) & CLKSEL_TIMER7_CLK_SEL_MASK) != CLKSEL_TIMER7_CLK_SEL_SEL2);
/* enable the module and wait for the module to be ready */
set32(CM_PER_TIMER7_CLKCTRL,CM_MODULEMODE_MASK,CM_MODULEMODE_ENABLE);
while( (mmio_read(CM_PER_TIMER7_CLKCTRL) & CM_CLKCTRL_IDLEST) != CM_CLKCTRL_IDLEST_FUNC);
#endif
/* Stop timer */
mmio_clear(fr_timer.base + fr_timer.regs->TCLR, OMAP3_TCLR_ST);
#ifdef DM37XX
/* Use functional clock source for GPTIMER10 */
mmio_set(OMAP3_CM_CLKSEL_CORE, OMAP3_CLKSEL_GPT10);
#endif
#ifdef DM37XX
/* Scale timer down to 13/8 = 1.625 Mhz to roughly get microsecond ticks */
/* The scale is computed as 2^(PTV+1). So if PTV == 2, we get 2^3 = 8.
*/
mmio_set(fr_timer.base + fr_timer.regs->TCLR, (2 << OMAP3_TCLR_PTV));
#endif
#ifdef AM335X
/* 24Mhz / 16 = 1.5 Mhz */
mmio_set(fr_timer.base + fr_timer.regs->TCLR, (3 << OMAP3_TCLR_PTV));
#endif
/* Start and auto-reload at 0 */
mmio_write(fr_timer.base + fr_timer.regs->TLDR, 0x0);
mmio_write(fr_timer.base + fr_timer.regs->TCRR, 0x0);
/* Set up overflow interrupt */
tisr = OMAP3_TISR_MAT_IT_FLAG | OMAP3_TISR_OVF_IT_FLAG |
OMAP3_TISR_TCAR_IT_FLAG;
mmio_write(fr_timer.base + fr_timer.regs->TISR, tisr); /* Clear interrupt status */
mmio_write(fr_timer.base + fr_timer.regs->TIER, OMAP3_TIER_OVF_IT_ENA);
/* Start timer */
mmio_set(fr_timer.base + fr_timer.regs->TCLR,
OMAP3_TCLR_OVF_TRG|OMAP3_TCLR_AR|OMAP3_TCLR_ST|OMAP3_TCLR_PRE);
done = 1;
}
void omap3_frclock_stop()
{
mmio_clear(fr_timer.base + fr_timer.regs->TCLR, OMAP3_TCLR_ST);
}
void omap3_timer_init(unsigned freq)
{
/* we only support 1ms resolution */
u32_t tisr;
kern_phys_map_ptr(timer.base,ARM_PAGE_SIZE,
&timer_phys_map, (vir_bytes) &timer.base);
#ifdef AM335X
/* disable the module and wait for the module to be disabled */
set32(CM_WKUP_TIMER1_CLKCTRL, CM_MODULEMODE_MASK,CM_MODULEMODE_DISABLED);
while( (mmio_read(CM_WKUP_TIMER1_CLKCTRL) & CM_CLKCTRL_IDLEST) != CM_CLKCTRL_IDLEST_DISABLE);
set32(CLKSEL_TIMER1MS_CLK,CLKSEL_TIMER1MS_CLK_SEL_MASK, CLKSEL_TIMER1MS_CLK_SEL_SEL2);
while( (read32(CLKSEL_TIMER1MS_CLK) & CLKSEL_TIMER1MS_CLK_SEL_MASK) != CLKSEL_TIMER1MS_CLK_SEL_SEL2);
/* enable the module and wait for the module to be ready */
set32(CM_WKUP_TIMER1_CLKCTRL,CM_MODULEMODE_MASK,CM_MODULEMODE_ENABLE);
while( (mmio_read(CM_WKUP_TIMER1_CLKCTRL) & CM_CLKCTRL_IDLEST) != CM_CLKCTRL_IDLEST_FUNC);
#endif
/* Stop timer */
mmio_clear(timer.base + fr_timer.regs->TCLR, OMAP3_TCLR_ST);
#ifdef DM37XX
/* Use 32 KHz clock source for GPTIMER1 */
mmio_clear(OMAP3_CM_CLKSEL_WKUP, OMAP3_CLKSEL_GPT1);
#endif
/* Use 1-ms tick mode for GPTIMER1 TRM 16.2.4.2.1 */
mmio_write(timer.base + timer.regs->TPIR, 232000);
mmio_write(timer.base + timer.regs->TNIR, -768000);
mmio_write(timer.base + timer.regs->TLDR, 0xffffffff - (32768 / freq) +1);
mmio_write(timer.base + timer.regs->TCRR, 0xffffffff - (32768 / freq) +1);
/* Set up overflow interrupt */
tisr = OMAP3_TISR_MAT_IT_FLAG | OMAP3_TISR_OVF_IT_FLAG |
OMAP3_TISR_TCAR_IT_FLAG;
mmio_write(timer.base + timer.regs->TISR, tisr); /* Clear interrupt status */
mmio_write(timer.base + timer.regs->TIER, OMAP3_TIER_OVF_IT_ENA);
/* Start timer */
mmio_set(timer.base + timer.regs->TCLR,
OMAP3_TCLR_OVF_TRG|OMAP3_TCLR_AR|OMAP3_TCLR_ST);
}
void omap3_timer_stop()
{
mmio_clear(timer.base + timer.regs->TCLR, OMAP3_TCLR_ST);
}
static u32_t read_frc(void)
{
if (done == 0)
return 0;
return mmio_read(fr_timer.base + fr_timer.regs->TCRR);
}
/*
* Check if the free running clock has overflown and
* increase the high free running clock counter if
* so. This method takes the current timer value as
* parameter to ensure the overflow check is done
* on the current timer value.
*
* To compose the current timer value (64 bits) you
* need to follow the following sequence:
* read the current timer value.
* call the overflow check
* compose the 64 bits time based on the current timer value
* and high_frc.
*/
static void frc_overflow_check(u32_t cur_frc)
{
static int prev_frc_valid;
static u32_t prev_frc;
if(prev_frc_valid && prev_frc > cur_frc)
high_frc++;
prev_frc = cur_frc;
prev_frc_valid = 1;
}
void omap3_timer_int_handler()
{
/* Clear all interrupts */
u32_t tisr,now;
/* when the kernel itself is running interrupts are disabled.
* We should therefore also read the overflow counter to detect
* this as to not miss events.
*/
tisr = OMAP3_TISR_MAT_IT_FLAG | OMAP3_TISR_OVF_IT_FLAG |
OMAP3_TISR_TCAR_IT_FLAG;
mmio_write(timer.base + timer.regs->TISR, tisr);
now = read_frc();
frc_overflow_check(now);
}
/* Use the free running clock as TSC */
void read_tsc_64(u64_t *t)
{
u32_t now;
now = read_frc();
frc_overflow_check(now);
*t = (u64_t) now + (high_frc << 32);
}