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