433 lines
10 KiB
C
433 lines
10 KiB
C
/*
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* IMX EPIT Timer
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*
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* Copyright (c) 2008 OK Labs
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* Copyright (c) 2011 NICTA Pty Ltd
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* Originally written by Hans Jiang
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* Updated by Peter Chubb
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* Updated by Jean-Christophe Dubois
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*
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* This code is licensed under GPL version 2 or later. See
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* the COPYING file in the top-level directory.
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*
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*/
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#include "hw/hw.h"
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#include "qemu/bitops.h"
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#include "qemu/timer.h"
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#include "hw/ptimer.h"
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#include "hw/sysbus.h"
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#include "hw/arm/imx.h"
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#define TYPE_IMX_EPIT "imx.epit"
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#define DEBUG_TIMER 0
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#if DEBUG_TIMER
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static char const *imx_epit_reg_name(uint32_t reg)
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{
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switch (reg) {
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case 0:
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return "CR";
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case 1:
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return "SR";
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case 2:
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return "LR";
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case 3:
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return "CMP";
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case 4:
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return "CNT";
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default:
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return "[?]";
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}
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}
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# define DPRINTF(fmt, args...) \
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do { printf("%s: " fmt , __func__, ##args); } while (0)
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#else
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# define DPRINTF(fmt, args...) do {} while (0)
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#endif
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/*
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* Define to 1 for messages about attempts to
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* access unimplemented registers or similar.
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*/
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#define DEBUG_IMPLEMENTATION 1
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#if DEBUG_IMPLEMENTATION
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# define IPRINTF(fmt, args...) \
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do { fprintf(stderr, "%s: " fmt, __func__, ##args); } while (0)
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#else
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# define IPRINTF(fmt, args...) do {} while (0)
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#endif
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#define IMX_EPIT(obj) \
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OBJECT_CHECK(IMXEPITState, (obj), TYPE_IMX_EPIT)
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/*
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* EPIT: Enhanced periodic interrupt timer
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*/
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#define CR_EN (1 << 0)
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#define CR_ENMOD (1 << 1)
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#define CR_OCIEN (1 << 2)
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#define CR_RLD (1 << 3)
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#define CR_PRESCALE_SHIFT (4)
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#define CR_PRESCALE_MASK (0xfff)
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#define CR_SWR (1 << 16)
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#define CR_IOVW (1 << 17)
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#define CR_DBGEN (1 << 18)
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#define CR_WAITEN (1 << 19)
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#define CR_DOZEN (1 << 20)
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#define CR_STOPEN (1 << 21)
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#define CR_CLKSRC_SHIFT (24)
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#define CR_CLKSRC_MASK (0x3 << CR_CLKSRC_SHIFT)
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#define TIMER_MAX 0XFFFFFFFFUL
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/*
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* Exact clock frequencies vary from board to board.
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* These are typical.
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*/
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static const IMXClk imx_epit_clocks[] = {
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0, /* 00 disabled */
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IPG, /* 01 ipg_clk, ~532MHz */
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IPG, /* 10 ipg_clk_highfreq */
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CLK_32k, /* 11 ipg_clk_32k -- ~32kHz */
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};
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typedef struct {
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SysBusDevice busdev;
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ptimer_state *timer_reload;
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ptimer_state *timer_cmp;
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MemoryRegion iomem;
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DeviceState *ccm;
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uint32_t cr;
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uint32_t sr;
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uint32_t lr;
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uint32_t cmp;
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uint32_t cnt;
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uint32_t freq;
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qemu_irq irq;
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} IMXEPITState;
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/*
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* Update interrupt status
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*/
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static void imx_epit_update_int(IMXEPITState *s)
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{
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if (s->sr && (s->cr & CR_OCIEN) && (s->cr & CR_EN)) {
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qemu_irq_raise(s->irq);
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} else {
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qemu_irq_lower(s->irq);
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}
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}
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static void imx_epit_set_freq(IMXEPITState *s)
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{
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uint32_t clksrc;
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uint32_t prescaler;
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uint32_t freq;
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clksrc = extract32(s->cr, CR_CLKSRC_SHIFT, 2);
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prescaler = 1 + extract32(s->cr, CR_PRESCALE_SHIFT, 12);
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freq = imx_clock_frequency(s->ccm, imx_epit_clocks[clksrc]) / prescaler;
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s->freq = freq;
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DPRINTF("Setting ptimer frequency to %u\n", freq);
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if (freq) {
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ptimer_set_freq(s->timer_reload, freq);
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ptimer_set_freq(s->timer_cmp, freq);
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}
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}
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static void imx_epit_reset(DeviceState *dev)
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{
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IMXEPITState *s = IMX_EPIT(dev);
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/*
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* Soft reset doesn't touch some bits; hard reset clears them
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*/
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s->cr &= ~(CR_EN|CR_ENMOD|CR_STOPEN|CR_DOZEN|CR_WAITEN|CR_DBGEN);
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s->sr = 0;
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s->lr = TIMER_MAX;
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s->cmp = 0;
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s->cnt = 0;
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/* stop both timers */
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ptimer_stop(s->timer_cmp);
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ptimer_stop(s->timer_reload);
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/* compute new frequency */
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imx_epit_set_freq(s);
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/* init both timers to TIMER_MAX */
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ptimer_set_limit(s->timer_cmp, TIMER_MAX, 1);
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ptimer_set_limit(s->timer_reload, TIMER_MAX, 1);
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if (s->freq && (s->cr & CR_EN)) {
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/* if the timer is still enabled, restart it */
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ptimer_run(s->timer_reload, 1);
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}
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}
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static uint32_t imx_epit_update_count(IMXEPITState *s)
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{
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s->cnt = ptimer_get_count(s->timer_reload);
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return s->cnt;
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}
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static uint64_t imx_epit_read(void *opaque, hwaddr offset, unsigned size)
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{
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IMXEPITState *s = IMX_EPIT(opaque);
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uint32_t reg_value = 0;
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uint32_t reg = offset >> 2;
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switch (reg) {
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case 0: /* Control Register */
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reg_value = s->cr;
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break;
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case 1: /* Status Register */
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reg_value = s->sr;
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break;
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case 2: /* LR - ticks*/
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reg_value = s->lr;
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break;
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case 3: /* CMP */
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reg_value = s->cmp;
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break;
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case 4: /* CNT */
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imx_epit_update_count(s);
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reg_value = s->cnt;
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break;
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default:
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IPRINTF("Bad offset %x\n", reg);
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break;
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}
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DPRINTF("(%s) = 0x%08x\n", imx_epit_reg_name(reg), reg_value);
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return reg_value;
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}
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static void imx_epit_reload_compare_timer(IMXEPITState *s)
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{
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if ((s->cr & CR_OCIEN) && s->cmp) {
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/* if the compare feature is on */
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uint32_t tmp = imx_epit_update_count(s);
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if (tmp > s->cmp) {
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/* reinit the cmp timer if required */
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ptimer_set_count(s->timer_cmp, tmp - s->cmp);
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if ((s->cr & CR_EN)) {
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/* Restart the cmp timer if required */
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ptimer_run(s->timer_cmp, 0);
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}
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}
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}
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}
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static void imx_epit_write(void *opaque, hwaddr offset, uint64_t value,
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unsigned size)
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{
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IMXEPITState *s = IMX_EPIT(opaque);
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uint32_t reg = offset >> 2;
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DPRINTF("(%s, value = 0x%08x)\n", imx_epit_reg_name(reg), (uint32_t)value);
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switch (reg) {
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case 0: /* CR */
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s->cr = value & 0x03ffffff;
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if (s->cr & CR_SWR) {
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/* handle the reset */
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imx_epit_reset(DEVICE(s));
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} else {
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imx_epit_set_freq(s);
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}
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if (s->freq && (s->cr & CR_EN)) {
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if (s->cr & CR_ENMOD) {
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if (s->cr & CR_RLD) {
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ptimer_set_limit(s->timer_reload, s->lr, 1);
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} else {
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ptimer_set_limit(s->timer_reload, TIMER_MAX, 1);
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}
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}
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imx_epit_reload_compare_timer(s);
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ptimer_run(s->timer_reload, 1);
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} else {
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/* stop both timers */
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ptimer_stop(s->timer_reload);
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ptimer_stop(s->timer_cmp);
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}
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break;
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case 1: /* SR - ACK*/
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/* writing 1 to OCIF clear the OCIF bit */
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if (value & 0x01) {
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s->sr = 0;
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imx_epit_update_int(s);
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}
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break;
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case 2: /* LR - set ticks */
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s->lr = value;
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if (s->cr & CR_RLD) {
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/* Also set the limit if the LRD bit is set */
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/* If IOVW bit is set then set the timer value */
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ptimer_set_limit(s->timer_reload, s->lr, s->cr & CR_IOVW);
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} else if (s->cr & CR_IOVW) {
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/* If IOVW bit is set then set the timer value */
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ptimer_set_count(s->timer_reload, s->lr);
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}
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imx_epit_reload_compare_timer(s);
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break;
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case 3: /* CMP */
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s->cmp = value;
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imx_epit_reload_compare_timer(s);
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break;
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default:
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IPRINTF("Bad offset %x\n", reg);
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break;
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}
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}
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static void imx_epit_timeout(void *opaque)
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{
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IMXEPITState *s = IMX_EPIT(opaque);
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DPRINTF("\n");
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if (!(s->cr & CR_EN)) {
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return;
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}
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if (s->cr & CR_RLD) {
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ptimer_set_limit(s->timer_reload, s->lr, 1);
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} else {
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ptimer_set_limit(s->timer_reload, TIMER_MAX, 1);
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}
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if (s->cr & CR_OCIEN) {
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/* if compare register is 0 then we handle the interrupt here */
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if (s->cmp == 0) {
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s->sr = 1;
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imx_epit_update_int(s);
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} else if (s->cmp <= s->lr) {
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/* We should launch the compare register */
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ptimer_set_count(s->timer_cmp, s->lr - s->cmp);
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ptimer_run(s->timer_cmp, 0);
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} else {
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IPRINTF("s->lr < s->cmp\n");
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}
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}
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}
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static void imx_epit_cmp(void *opaque)
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{
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IMXEPITState *s = IMX_EPIT(opaque);
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DPRINTF("\n");
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ptimer_stop(s->timer_cmp);
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/* compare register is not 0 */
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if (s->cmp) {
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s->sr = 1;
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imx_epit_update_int(s);
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}
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}
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void imx_timerp_create(const hwaddr addr, qemu_irq irq, DeviceState *ccm)
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{
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IMXEPITState *pp;
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DeviceState *dev;
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dev = sysbus_create_simple(TYPE_IMX_EPIT, addr, irq);
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pp = IMX_EPIT(dev);
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pp->ccm = ccm;
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}
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static const MemoryRegionOps imx_epit_ops = {
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.read = imx_epit_read,
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.write = imx_epit_write,
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.endianness = DEVICE_NATIVE_ENDIAN,
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};
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static const VMStateDescription vmstate_imx_timer_epit = {
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.name = TYPE_IMX_EPIT,
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.version_id = 2,
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.minimum_version_id = 2,
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.minimum_version_id_old = 2,
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.fields = (VMStateField[]) {
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VMSTATE_UINT32(cr, IMXEPITState),
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VMSTATE_UINT32(sr, IMXEPITState),
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VMSTATE_UINT32(lr, IMXEPITState),
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VMSTATE_UINT32(cmp, IMXEPITState),
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VMSTATE_UINT32(cnt, IMXEPITState),
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VMSTATE_UINT32(freq, IMXEPITState),
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VMSTATE_PTIMER(timer_reload, IMXEPITState),
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VMSTATE_PTIMER(timer_cmp, IMXEPITState),
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VMSTATE_END_OF_LIST()
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}
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};
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static void imx_epit_realize(DeviceState *dev, Error **errp)
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{
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IMXEPITState *s = IMX_EPIT(dev);
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SysBusDevice *sbd = SYS_BUS_DEVICE(dev);
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QEMUBH *bh;
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DPRINTF("\n");
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sysbus_init_irq(sbd, &s->irq);
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memory_region_init_io(&s->iomem, OBJECT(s), &imx_epit_ops, s, TYPE_IMX_EPIT,
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0x00001000);
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sysbus_init_mmio(sbd, &s->iomem);
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bh = qemu_bh_new(imx_epit_timeout, s);
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s->timer_reload = ptimer_init(bh);
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bh = qemu_bh_new(imx_epit_cmp, s);
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s->timer_cmp = ptimer_init(bh);
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}
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static void imx_epit_class_init(ObjectClass *klass, void *data)
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{
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DeviceClass *dc = DEVICE_CLASS(klass);
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dc->realize = imx_epit_realize;
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dc->reset = imx_epit_reset;
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dc->vmsd = &vmstate_imx_timer_epit;
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dc->desc = "i.MX periodic timer";
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}
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static const TypeInfo imx_epit_info = {
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.name = TYPE_IMX_EPIT,
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.parent = TYPE_SYS_BUS_DEVICE,
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.instance_size = sizeof(IMXEPITState),
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.class_init = imx_epit_class_init,
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};
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static void imx_epit_register_types(void)
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{
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type_register_static(&imx_epit_info);
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}
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type_init(imx_epit_register_types)
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