diff options
Diffstat (limited to 'hw/timer/imx_epit.c')
| -rw-r--r-- | hw/timer/imx_epit.c | 432 |
1 files changed, 432 insertions, 0 deletions
diff --git a/hw/timer/imx_epit.c b/hw/timer/imx_epit.c new file mode 100644 index 0000000000..7cdb0060ab --- /dev/null +++ b/hw/timer/imx_epit.c @@ -0,0 +1,432 @@ +/* + * IMX EPIT Timer + * + * Copyright (c) 2008 OK Labs + * Copyright (c) 2011 NICTA Pty Ltd + * Originally written by Hans Jiang + * Updated by Peter Chubb + * Updated by Jean-Christophe Dubois + * + * This code is licensed under GPL version 2 or later. See + * the COPYING file in the top-level directory. + * + */ + +#include "hw/hw.h" +#include "qemu/bitops.h" +#include "qemu/timer.h" +#include "hw/ptimer.h" +#include "hw/sysbus.h" +#include "hw/arm/imx.h" + +#define TYPE_IMX_EPIT "imx.epit" + +#define DEBUG_TIMER 0 +#if DEBUG_TIMER + +static char const *imx_epit_reg_name(uint32_t reg) +{ + switch (reg) { + case 0: + return "CR"; + case 1: + return "SR"; + case 2: + return "LR"; + case 3: + return "CMP"; + case 4: + return "CNT"; + default: + return "[?]"; + } +} + +# define DPRINTF(fmt, args...) \ + do { printf("%s: " fmt , __func__, ##args); } while (0) +#else +# define DPRINTF(fmt, args...) do {} while (0) +#endif + +/* + * Define to 1 for messages about attempts to + * access unimplemented registers or similar. + */ +#define DEBUG_IMPLEMENTATION 1 +#if DEBUG_IMPLEMENTATION +# define IPRINTF(fmt, args...) \ + do { fprintf(stderr, "%s: " fmt, __func__, ##args); } while (0) +#else +# define IPRINTF(fmt, args...) do {} while (0) +#endif + +#define IMX_EPIT(obj) \ + OBJECT_CHECK(IMXEPITState, (obj), TYPE_IMX_EPIT) + +/* + * EPIT: Enhanced periodic interrupt timer + */ + +#define CR_EN (1 << 0) +#define CR_ENMOD (1 << 1) +#define CR_OCIEN (1 << 2) +#define CR_RLD (1 << 3) +#define CR_PRESCALE_SHIFT (4) +#define CR_PRESCALE_MASK (0xfff) +#define CR_SWR (1 << 16) +#define CR_IOVW (1 << 17) +#define CR_DBGEN (1 << 18) +#define CR_WAITEN (1 << 19) +#define CR_DOZEN (1 << 20) +#define CR_STOPEN (1 << 21) +#define CR_CLKSRC_SHIFT (24) +#define CR_CLKSRC_MASK (0x3 << CR_CLKSRC_SHIFT) + +#define TIMER_MAX 0XFFFFFFFFUL + +/* + * Exact clock frequencies vary from board to board. + * These are typical. + */ +static const IMXClk imx_epit_clocks[] = { + 0, /* 00 disabled */ + IPG, /* 01 ipg_clk, ~532MHz */ + IPG, /* 10 ipg_clk_highfreq */ + CLK_32k, /* 11 ipg_clk_32k -- ~32kHz */ +}; + +typedef struct { + SysBusDevice busdev; + ptimer_state *timer_reload; + ptimer_state *timer_cmp; + MemoryRegion iomem; + DeviceState *ccm; + + uint32_t cr; + uint32_t sr; + uint32_t lr; + uint32_t cmp; + uint32_t cnt; + + uint32_t freq; + qemu_irq irq; +} IMXEPITState; + +/* + * Update interrupt status + */ +static void imx_epit_update_int(IMXEPITState *s) +{ + if (s->sr && (s->cr & CR_OCIEN) && (s->cr & CR_EN)) { + qemu_irq_raise(s->irq); + } else { + qemu_irq_lower(s->irq); + } +} + +static void imx_epit_set_freq(IMXEPITState *s) +{ + uint32_t clksrc; + uint32_t prescaler; + uint32_t freq; + + clksrc = extract32(s->cr, CR_CLKSRC_SHIFT, 2); + prescaler = 1 + extract32(s->cr, CR_PRESCALE_SHIFT, 12); + + freq = imx_clock_frequency(s->ccm, imx_epit_clocks[clksrc]) / prescaler; + + s->freq = freq; + + DPRINTF("Setting ptimer frequency to %u\n", freq); + + if (freq) { + ptimer_set_freq(s->timer_reload, freq); + ptimer_set_freq(s->timer_cmp, freq); + } +} + +static void imx_epit_reset(DeviceState *dev) +{ + IMXEPITState *s = IMX_EPIT(dev); + + /* + * Soft reset doesn't touch some bits; hard reset clears them + */ + s->cr &= ~(CR_EN|CR_ENMOD|CR_STOPEN|CR_DOZEN|CR_WAITEN|CR_DBGEN); + s->sr = 0; + s->lr = TIMER_MAX; + s->cmp = 0; + s->cnt = 0; + /* stop both timers */ + ptimer_stop(s->timer_cmp); + ptimer_stop(s->timer_reload); + /* compute new frequency */ + imx_epit_set_freq(s); + /* init both timers to TIMER_MAX */ + ptimer_set_limit(s->timer_cmp, TIMER_MAX, 1); + ptimer_set_limit(s->timer_reload, TIMER_MAX, 1); + if (s->freq && (s->cr & CR_EN)) { + /* if the timer is still enabled, restart it */ + ptimer_run(s->timer_reload, 1); + } +} + +static uint32_t imx_epit_update_count(IMXEPITState *s) +{ + s->cnt = ptimer_get_count(s->timer_reload); + + return s->cnt; +} + +static uint64_t imx_epit_read(void *opaque, hwaddr offset, unsigned size) +{ + IMXEPITState *s = IMX_EPIT(opaque); + uint32_t reg_value = 0; + uint32_t reg = offset >> 2; + + switch (reg) { + case 0: /* Control Register */ + reg_value = s->cr; + break; + + case 1: /* Status Register */ + reg_value = s->sr; + break; + + case 2: /* LR - ticks*/ + reg_value = s->lr; + break; + + case 3: /* CMP */ + reg_value = s->cmp; + break; + + case 4: /* CNT */ + imx_epit_update_count(s); + reg_value = s->cnt; + break; + + default: + IPRINTF("Bad offset %x\n", reg); + break; + } + + DPRINTF("(%s) = 0x%08x\n", imx_epit_reg_name(reg), reg_value); + + return reg_value; +} + +static void imx_epit_reload_compare_timer(IMXEPITState *s) +{ + if ((s->cr & CR_OCIEN) && s->cmp) { + /* if the compare feature is on */ + uint32_t tmp = imx_epit_update_count(s); + if (tmp > s->cmp) { + /* reinit the cmp timer if required */ + ptimer_set_count(s->timer_cmp, tmp - s->cmp); + if ((s->cr & CR_EN)) { + /* Restart the cmp timer if required */ + ptimer_run(s->timer_cmp, 0); + } + } + } +} + +static void imx_epit_write(void *opaque, hwaddr offset, uint64_t value, + unsigned size) +{ + IMXEPITState *s = IMX_EPIT(opaque); + uint32_t reg = offset >> 2; + + DPRINTF("(%s, value = 0x%08x)\n", imx_epit_reg_name(reg), (uint32_t)value); + + switch (reg) { + case 0: /* CR */ + s->cr = value & 0x03ffffff; + if (s->cr & CR_SWR) { + /* handle the reset */ + imx_epit_reset(DEVICE(s)); + } else { + imx_epit_set_freq(s); + } + + if (s->freq && (s->cr & CR_EN)) { + if (s->cr & CR_ENMOD) { + if (s->cr & CR_RLD) { + ptimer_set_limit(s->timer_reload, s->lr, 1); + } else { + ptimer_set_limit(s->timer_reload, TIMER_MAX, 1); + } + } + + imx_epit_reload_compare_timer(s); + + ptimer_run(s->timer_reload, 1); + } else { + /* stop both timers */ + ptimer_stop(s->timer_reload); + ptimer_stop(s->timer_cmp); + } + break; + + case 1: /* SR - ACK*/ + /* writing 1 to OCIF clear the OCIF bit */ + if (value & 0x01) { + s->sr = 0; + imx_epit_update_int(s); + } + break; + + case 2: /* LR - set ticks */ + s->lr = value; + + if (s->cr & CR_RLD) { + /* Also set the limit if the LRD bit is set */ + /* If IOVW bit is set then set the timer value */ + ptimer_set_limit(s->timer_reload, s->lr, s->cr & CR_IOVW); + } else if (s->cr & CR_IOVW) { + /* If IOVW bit is set then set the timer value */ + ptimer_set_count(s->timer_reload, s->lr); + } + + imx_epit_reload_compare_timer(s); + + break; + + case 3: /* CMP */ + s->cmp = value; + + imx_epit_reload_compare_timer(s); + + break; + + default: + IPRINTF("Bad offset %x\n", reg); + + break; + } +} + +static void imx_epit_timeout(void *opaque) +{ + IMXEPITState *s = IMX_EPIT(opaque); + + DPRINTF("\n"); + + if (!(s->cr & CR_EN)) { + return; + } + + if (s->cr & CR_RLD) { + ptimer_set_limit(s->timer_reload, s->lr, 1); + } else { + ptimer_set_limit(s->timer_reload, TIMER_MAX, 1); + } + + if (s->cr & CR_OCIEN) { + /* if compare register is 0 then we handle the interrupt here */ + if (s->cmp == 0) { + s->sr = 1; + imx_epit_update_int(s); + } else if (s->cmp <= s->lr) { + /* We should launch the compare register */ + ptimer_set_count(s->timer_cmp, s->lr - s->cmp); + ptimer_run(s->timer_cmp, 0); + } else { + IPRINTF("s->lr < s->cmp\n"); + } + } +} + +static void imx_epit_cmp(void *opaque) +{ + IMXEPITState *s = IMX_EPIT(opaque); + + DPRINTF("\n"); + + ptimer_stop(s->timer_cmp); + + /* compare register is not 0 */ + if (s->cmp) { + s->sr = 1; + imx_epit_update_int(s); + } +} + +void imx_timerp_create(const hwaddr addr, qemu_irq irq, DeviceState *ccm) +{ + IMXEPITState *pp; + DeviceState *dev; + + dev = sysbus_create_simple(TYPE_IMX_EPIT, addr, irq); + pp = IMX_EPIT(dev); + pp->ccm = ccm; +} + +static const MemoryRegionOps imx_epit_ops = { + .read = imx_epit_read, + .write = imx_epit_write, + .endianness = DEVICE_NATIVE_ENDIAN, +}; + +static const VMStateDescription vmstate_imx_timer_epit = { + .name = TYPE_IMX_EPIT, + .version_id = 2, + .minimum_version_id = 2, + .minimum_version_id_old = 2, + .fields = (VMStateField[]) { + VMSTATE_UINT32(cr, IMXEPITState), + VMSTATE_UINT32(sr, IMXEPITState), + VMSTATE_UINT32(lr, IMXEPITState), + VMSTATE_UINT32(cmp, IMXEPITState), + VMSTATE_UINT32(cnt, IMXEPITState), + VMSTATE_UINT32(freq, IMXEPITState), + VMSTATE_PTIMER(timer_reload, IMXEPITState), + VMSTATE_PTIMER(timer_cmp, IMXEPITState), + VMSTATE_END_OF_LIST() + } +}; + +static void imx_epit_realize(DeviceState *dev, Error **errp) +{ + IMXEPITState *s = IMX_EPIT(dev); + SysBusDevice *sbd = SYS_BUS_DEVICE(dev); + QEMUBH *bh; + + DPRINTF("\n"); + + sysbus_init_irq(sbd, &s->irq); + memory_region_init_io(&s->iomem, &imx_epit_ops, s, TYPE_IMX_EPIT, + 0x00001000); + sysbus_init_mmio(sbd, &s->iomem); + + bh = qemu_bh_new(imx_epit_timeout, s); + s->timer_reload = ptimer_init(bh); + + bh = qemu_bh_new(imx_epit_cmp, s); + s->timer_cmp = ptimer_init(bh); +} + +static void imx_epit_class_init(ObjectClass *klass, void *data) +{ + DeviceClass *dc = DEVICE_CLASS(klass); + + dc->realize = imx_epit_realize; + dc->reset = imx_epit_reset; + dc->vmsd = &vmstate_imx_timer_epit; + dc->desc = "i.MX periodic timer"; +} + +static const TypeInfo imx_epit_info = { + .name = TYPE_IMX_EPIT, + .parent = TYPE_SYS_BUS_DEVICE, + .instance_size = sizeof(IMXEPITState), + .class_init = imx_epit_class_init, +}; + +static void imx_epit_register_types(void) +{ + type_register_static(&imx_epit_info); +} + +type_init(imx_epit_register_types) |