- 根目录:
- arch
- powerpc
- sysdev
- fsl_gtm.c
/*
* Freescale General-purpose Timers Module
*
* Copyright (c) Freescale Semiconductor, Inc. 2006.
* Shlomi Gridish <gridish@freescale.com>
* Jerry Huang <Chang-Ming.Huang@freescale.com>
* Copyright (c) MontaVista Software, Inc. 2008.
* Anton Vorontsov <avorontsov@ru.mvista.com>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version.
*/
#include <linux/kernel.h>
#include <linux/err.h>
#include <linux/errno.h>
#include <linux/list.h>
#include <linux/io.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/spinlock.h>
#include <linux/bitops.h>
#include <linux/slab.h>
#include <linux/export.h>
#include <asm/fsl_gtm.h>
#define GTCFR_STP(x) ((x) & 1 ? 1 << 5 : 1 << 1)
#define GTCFR_RST(x) ((x) & 1 ? 1 << 4 : 1 << 0)
#define GTMDR_ICLK_MASK (3 << 1)
#define GTMDR_ICLK_ICAS (0 << 1)
#define GTMDR_ICLK_ICLK (1 << 1)
#define GTMDR_ICLK_SLGO (2 << 1)
#define GTMDR_FRR (1 << 3)
#define GTMDR_ORI (1 << 4)
#define GTMDR_SPS(x) ((x) << 8)
struct gtm_timers_regs {
u8 gtcfr1; /* Timer 1, Timer 2 global config register */
u8 res0[0x3];
u8 gtcfr2; /* Timer 3, timer 4 global config register */
u8 res1[0xB];
__be16 gtmdr1; /* Timer 1 mode register */
__be16 gtmdr2; /* Timer 2 mode register */
__be16 gtrfr1; /* Timer 1 reference register */
__be16 gtrfr2; /* Timer 2 reference register */
__be16 gtcpr1; /* Timer 1 capture register */
__be16 gtcpr2; /* Timer 2 capture register */
__be16 gtcnr1; /* Timer 1 counter */
__be16 gtcnr2; /* Timer 2 counter */
__be16 gtmdr3; /* Timer 3 mode register */
__be16 gtmdr4; /* Timer 4 mode register */
__be16 gtrfr3; /* Timer 3 reference register */
__be16 gtrfr4; /* Timer 4 reference register */
__be16 gtcpr3; /* Timer 3 capture register */
__be16 gtcpr4; /* Timer 4 capture register */
__be16 gtcnr3; /* Timer 3 counter */
__be16 gtcnr4; /* Timer 4 counter */
__be16 gtevr1; /* Timer 1 event register */
__be16 gtevr2; /* Timer 2 event register */
__be16 gtevr3; /* Timer 3 event register */
__be16 gtevr4; /* Timer 4 event register */
__be16 gtpsr1; /* Timer 1 prescale register */
__be16 gtpsr2; /* Timer 2 prescale register */
__be16 gtpsr3; /* Timer 3 prescale register */
__be16 gtpsr4; /* Timer 4 prescale register */
u8 res2[0x40];
} __attribute__ ((packed));
struct gtm {
unsigned int clock;
struct gtm_timers_regs __iomem *regs;
struct gtm_timer timers[4];
spinlock_t lock;
struct list_head list_node;
};
static LIST_HEAD(gtms);
/**
* gtm_get_timer - request GTM timer to use it with the rest of GTM API
* Context: non-IRQ
*
* This function reserves GTM timer for later use. It returns gtm_timer
* structure to use with the rest of GTM API, you should use timer->irq
* to manage timer interrupt.
*/
struct gtm_timer *gtm_get_timer16(void)
{
struct gtm *gtm = NULL;
int i;
list_for_each_entry(gtm, >ms, list_node) {
spin_lock_irq(>m->lock);
for (i = 0; i < ARRAY_SIZE(gtm->timers); i++) {
if (!gtm->timers[i].requested) {
gtm->timers[i].requested = true;
spin_unlock_irq(>m->lock);
return >m->timers[i];
}
}
spin_unlock_irq(>m->lock);
}
if (gtm)
return ERR_PTR(-EBUSY);
return ERR_PTR(-ENODEV);
}
EXPORT_SYMBOL(gtm_get_timer16);
/**
* gtm_get_specific_timer - request specific GTM timer
* @gtm: specific GTM, pass here GTM's device_node->data
* @timer: specific timer number, Timer1 is 0.
* Context: non-IRQ
*
* This function reserves GTM timer for later use. It returns gtm_timer
* structure to use with the rest of GTM API, you should use timer->irq
* to manage timer interrupt.
*/
struct gtm_timer *gtm_get_specific_timer16(struct gtm *gtm,
unsigned int timer)
{
struct gtm_timer *ret = ERR_PTR(-EBUSY);
if (timer > 3)
return ERR_PTR(-EINVAL);
spin_lock_irq(>m->lock);
if (gtm->timers[timer].requested)
goto out;
ret = >m->timers[timer];
ret->requested = true;
out:
spin_unlock_irq(>m->lock);
return ret;
}
EXPORT_SYMBOL(gtm_get_specific_timer16);
/**
* gtm_put_timer16 - release 16 bits GTM timer
* @tmr: pointer to the gtm_timer structure obtained from gtm_get_timer
* Context: any
*
* This function releases GTM timer so others may request it.
*/
void gtm_put_timer16(struct gtm_timer *tmr)
{
gtm_stop_timer16(tmr);
spin_lock_irq(&tmr->gtm->lock);
tmr->requested = false;
spin_unlock_irq(&tmr->gtm->lock);
}
EXPORT_SYMBOL(gtm_put_timer16);
/*
* This is back-end for the exported functions, it's used to reset single
* timer in reference mode.
*/
static int gtm_set_ref_timer16(struct gtm_timer *tmr, int frequency,
int reference_value, bool free_run)
{
struct gtm *gtm = tmr->gtm;
int num = tmr - >m->timers[0];
unsigned int prescaler;
u8 iclk = GTMDR_ICLK_ICLK;
u8 psr;
u8 sps;
unsigned long flags;
int max_prescaler = 256 * 256 * 16;
/* CPM2 doesn't have primary prescaler */
if (!tmr->gtpsr)
max_prescaler /= 256;
prescaler = gtm->clock / frequency;
/*
* We have two 8 bit prescalers -- primary and secondary (psr, sps),
* plus "slow go" mode (clk / 16). So, total prescale value is
* 16 * (psr + 1) * (sps + 1). Though, for CPM2 GTMs we losing psr.
*/
if (prescaler > max_prescaler)
return -EINVAL;
if (prescaler > max_prescaler / 16) {
iclk = GTMDR_ICLK_SLGO;
prescaler /= 16;
}
if (prescaler <= 256) {
psr = 0;
sps = prescaler - 1;
} else {
psr = 256 - 1;
sps = prescaler / 256 - 1;
}
spin_lock_irqsave(>m->lock, flags);
/*
* Properly reset timers: stop, reset, set up prescalers, reference
* value and clear event register.
*/
clrsetbits_8(tmr->gtcfr, ~(GTCFR_STP(num) | GTCFR_RST(num)),
GTCFR_STP(num) | GTCFR_RST(num));
setbits8(tmr->gtcfr, GTCFR_STP(num));
if (tmr->gtpsr)
out_be16(tmr->gtpsr, psr);
clrsetbits_be16(tmr->gtmdr, 0xFFFF, iclk | GTMDR_SPS(sps) |
GTMDR_ORI | (free_run ? GTMDR_FRR : 0));
out_be16(tmr->gtcnr, 0);
out_be16(tmr->gtrfr, reference_value);
out_be16(tmr->gtevr, 0xFFFF);
/* Let it be. */
clrbits8(tmr->gtcfr, GTCFR_STP(num));
spin_unlock_irqrestore(>m->lock, flags);
return 0;
}
/**
* gtm_set_timer16 - (re)set 16 bit timer with arbitrary precision
* @tmr: pointer to the gtm_timer structure obtained from gtm_get_timer
* @usec: timer interval in microseconds
* @reload: if set, the timer will reset upon expiry rather than
* continue running free.
* Context: any
*
* This function (re)sets the GTM timer so that it counts up to the requested
* interval value, and fires the interrupt when the value is reached. This
* function will reduce the precision of the timer as needed in order for the
* requested timeout to fit in a 16-bit register.
*/
int gtm_set_timer16(struct gtm_timer *tmr, unsigned long usec, bool reload)
{
/* quite obvious, frequency which is enough for µSec precision */
int freq = 1000000;
unsigned int bit;
bit = fls_long(usec);
if (bit > 15) {
freq >>= bit - 15;
usec >>= bit - 15;
}
if (!freq)
return -EINVAL;
return gtm_set_ref_timer16(tmr, freq, usec, reload);
}
EXPORT_SYMBOL(gtm_set_timer16);
/**
* gtm_set_exact_utimer16 - (re)set 16 bits timer
* @tmr: pointer to the gtm_timer structure obtained from gtm_get_timer
* @usec: timer interval in microseconds
* @reload: if set, the timer will reset upon expiry rather than
* continue running free.
* Context: any
*
* This function (re)sets GTM timer so that it counts up to the requested
* interval value, and fires the interrupt when the value is reached. If reload
* flag was set, timer will also reset itself upon reference value, otherwise
* it continues to increment.
*
* The _exact_ bit in the function name states that this function will not
* crop precision of the "usec" argument, thus usec is limited to 16 bits
* (single timer width).
*/
int gtm_set_exact_timer16(struct gtm_timer *tmr, u16 usec, bool reload)
{
/* quite obvious, frequency which is enough for µSec precision */
const int freq = 1000000;
/*
* We can lower the frequency (and probably power consumption) by
* dividing both frequency and usec by 2 until there is no remainder.
* But we won't bother with this unless savings are measured, so just
* run the timer as is.
*/
return gtm_set_ref_timer16(tmr, freq, usec, reload);
}
EXPORT_SYMBOL(gtm_set_exact_timer16);
/**
* gtm_stop_timer16 - stop single timer
* @tmr: pointer to the gtm_timer structure obtained from gtm_get_timer
* Context: any
*
* This function simply stops the GTM timer.
*/
void gtm_stop_timer16(struct gtm_timer *tmr)
{
struct gtm *gtm = tmr->gtm;
int num = tmr - >m->timers[0];
unsigned long flags;
spin_lock_irqsave(>m->lock, flags);
setbits8(tmr->gtcfr, GTCFR_STP(num));
out_be16(tmr->gtevr, 0xFFFF);
spin_unlock_irqrestore(>m->lock, flags);
}
EXPORT_SYMBOL(gtm_stop_timer16);
/**
* gtm_ack_timer16 - acknowledge timer event (free-run timers only)
* @tmr: pointer to the gtm_timer structure obtained from gtm_get_timer
* @events: events mask to ack
* Context: any
*
* Thus function used to acknowledge timer interrupt event, use it inside the
* interrupt handler.
*/
void gtm_ack_timer16(struct gtm_timer *tmr, u16 events)
{
out_be16(tmr->gtevr, events);
}
EXPORT_SYMBOL(gtm_ack_timer16);
static void __init gtm_set_shortcuts(struct device_node *np,
struct gtm_timer *timers,
struct gtm_timers_regs __iomem *regs)
{
/*
* Yeah, I don't like this either, but timers' registers a bit messed,
* so we have to provide shortcuts to write timer independent code.
* Alternative option is to create gt*() accessors, but that will be
* even uglier and cryptic.
*/
timers[0].gtcfr = ®s->gtcfr1;
timers[0].gtmdr = ®s->gtmdr1;
timers[0].gtcnr = ®s->gtcnr1;
timers[0].gtrfr = ®s->gtrfr1;
timers[0].gtevr = ®s->gtevr1;
timers[1].gtcfr = ®s->gtcfr1;
timers[1].gtmdr = ®s->gtmdr2;
timers[1].gtcnr = ®s->gtcnr2;
timers[1].gtrfr = ®s->gtrfr2;
timers[1].gtevr = ®s->gtevr2;
timers[2].gtcfr = ®s->gtcfr2;
timers[2].gtmdr = ®s->gtmdr3;
timers[2].gtcnr = ®s->gtcnr3;
timers[2].gtrfr = ®s->gtrfr3;
timers[2].gtevr = ®s->gtevr3;
timers[3].gtcfr = ®s->gtcfr2;
timers[3].gtmdr = ®s->gtmdr4;
timers[3].gtcnr = ®s->gtcnr4;
timers[3].gtrfr = ®s->gtrfr4;
timers[3].gtevr = ®s->gtevr4;
/* CPM2 doesn't have primary prescaler */
if (!of_device_is_compatible(np, "fsl,cpm2-gtm")) {
timers[0].gtpsr = ®s->gtpsr1;
timers[1].gtpsr = ®s->gtpsr2;
timers[2].gtpsr = ®s->gtpsr3;
timers[3].gtpsr = ®s->gtpsr4;
}
}
static int __init fsl_gtm_init(void)
{
struct device_node *np;
for_each_compatible_node(np, NULL, "fsl,gtm") {
int i;
struct gtm *gtm;
const u32 *clock;
int size;
gtm = kzalloc(sizeof(*gtm), GFP_KERNEL);
if (!gtm) {
pr_err("%s: unable to allocate memory\n",
np->full_name);
continue;
}
spin_lock_init(>m->lock);
clock = of_get_property(np, "clock-frequency", &size);
if (!clock || size != sizeof(*clock)) {
pr_err("%s: no clock-frequency\n", np->full_name);
goto err;
}
gtm->clock = *clock;
for (i = 0; i < ARRAY_SIZE(gtm->timers); i++) {
unsigned int irq;
irq = irq_of_parse_and_map(np, i);
if (irq == NO_IRQ) {
pr_err("%s: not enough interrupts specified\n",
np->full_name);
goto err;
}
gtm->timers[i].irq = irq;
gtm->timers[i].gtm = gtm;
}
gtm->regs = of_iomap(np, 0);
if (!gtm->regs) {
pr_err("%s: unable to iomap registers\n",
np->full_name);
goto err;
}
gtm_set_shortcuts(np, gtm->timers, gtm->regs);
list_add(>m->list_node, >ms);
/* We don't want to lose the node and its ->data */
np->data = gtm;
of_node_get(np);
continue;
err:
kfree(gtm);
}
return 0;
}
arch_initcall(fsl_gtm_init);