| /* |
| * ARM MPS2 AN505 FPGAIO emulation |
| * |
| * Copyright (c) 2018 Linaro Limited |
| * Written by Peter Maydell |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License version 2 or |
| * (at your option) any later version. |
| */ |
| |
| /* This is a model of the "FPGA system control and I/O" block found |
| * in the AN505 FPGA image for the MPS2 devboard. |
| * It is documented in AN505: |
| * https://developer.arm.com/documentation/dai0505/latest/ |
| */ |
| |
| #include "qemu/osdep.h" |
| #include "qemu/log.h" |
| #include "qemu/module.h" |
| #include "qapi/error.h" |
| #include "trace.h" |
| #include "hw/sysbus.h" |
| #include "migration/vmstate.h" |
| #include "hw/registerfields.h" |
| #include "hw/misc/mps2-fpgaio.h" |
| #include "hw/misc/led.h" |
| #include "hw/qdev-properties.h" |
| #include "qemu/timer.h" |
| |
| REG32(LED0, 0) |
| REG32(DBGCTRL, 4) |
| REG32(BUTTON, 8) |
| REG32(CLK1HZ, 0x10) |
| REG32(CLK100HZ, 0x14) |
| REG32(COUNTER, 0x18) |
| REG32(PRESCALE, 0x1c) |
| REG32(PSCNTR, 0x20) |
| REG32(SWITCH, 0x28) |
| REG32(MISC, 0x4c) |
| |
| static uint32_t counter_from_tickoff(int64_t now, int64_t tick_offset, int frq) |
| { |
| return muldiv64(now - tick_offset, frq, NANOSECONDS_PER_SECOND); |
| } |
| |
| static int64_t tickoff_from_counter(int64_t now, uint32_t count, int frq) |
| { |
| return now - muldiv64(count, NANOSECONDS_PER_SECOND, frq); |
| } |
| |
| static void resync_counter(MPS2FPGAIO *s) |
| { |
| /* |
| * Update s->counter and s->pscntr to their true current values |
| * by calculating how many times PSCNTR has ticked since the |
| * last time we did a resync. |
| */ |
| int64_t now = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL); |
| int64_t elapsed = now - s->pscntr_sync_ticks; |
| |
| /* |
| * Round elapsed down to a whole number of PSCNTR ticks, so we don't |
| * lose time if we do multiple resyncs in a single tick. |
| */ |
| uint64_t ticks = muldiv64(elapsed, s->prescale_clk, NANOSECONDS_PER_SECOND); |
| |
| /* |
| * Work out what PSCNTR and COUNTER have moved to. We assume that |
| * PSCNTR reloads from PRESCALE one tick-period after it hits zero, |
| * and that COUNTER increments at the same moment. |
| */ |
| if (ticks == 0) { |
| /* We haven't ticked since the last time we were asked */ |
| return; |
| } else if (ticks < s->pscntr) { |
| /* We haven't yet reached zero, just reduce the PSCNTR */ |
| s->pscntr -= ticks; |
| } else { |
| if (s->prescale == 0) { |
| /* |
| * If the reload value is zero then the PSCNTR will stick |
| * at zero once it reaches it, and so we will increment |
| * COUNTER every tick after that. |
| */ |
| s->counter += ticks - s->pscntr; |
| s->pscntr = 0; |
| } else { |
| /* |
| * This is the complicated bit. This ASCII art diagram gives an |
| * example with PRESCALE==5 PSCNTR==7: |
| * |
| * ticks 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 |
| * PSCNTR 7 6 5 4 3 2 1 0 5 4 3 2 1 0 5 |
| * cinc 1 2 |
| * y 0 1 2 3 4 5 6 7 8 9 10 11 12 |
| * x 0 1 2 3 4 5 0 1 2 3 4 5 0 |
| * |
| * where x = y % (s->prescale + 1) |
| * and so PSCNTR = s->prescale - x |
| * and COUNTER is incremented by y / (s->prescale + 1) |
| * |
| * The case where PSCNTR < PRESCALE works out the same, |
| * though we must be careful to calculate y as 64-bit unsigned |
| * for all parts of the expression. |
| * y < 0 is not possible because that implies ticks < s->pscntr. |
| */ |
| uint64_t y = ticks - s->pscntr + s->prescale; |
| s->pscntr = s->prescale - (y % (s->prescale + 1)); |
| s->counter += y / (s->prescale + 1); |
| } |
| } |
| |
| /* |
| * Only advance the sync time to the timestamp of the last PSCNTR tick, |
| * not all the way to 'now', so we don't lose time if we do multiple |
| * resyncs in a single tick. |
| */ |
| s->pscntr_sync_ticks += muldiv64(ticks, NANOSECONDS_PER_SECOND, |
| s->prescale_clk); |
| } |
| |
| static uint64_t mps2_fpgaio_read(void *opaque, hwaddr offset, unsigned size) |
| { |
| MPS2FPGAIO *s = MPS2_FPGAIO(opaque); |
| uint64_t r; |
| int64_t now; |
| |
| switch (offset) { |
| case A_LED0: |
| r = s->led0; |
| break; |
| case A_DBGCTRL: |
| if (!s->has_dbgctrl) { |
| goto bad_offset; |
| } |
| r = s->dbgctrl; |
| break; |
| case A_BUTTON: |
| /* User-pressable board buttons. We don't model that, so just return |
| * zeroes. |
| */ |
| r = 0; |
| break; |
| case A_PRESCALE: |
| r = s->prescale; |
| break; |
| case A_MISC: |
| r = s->misc; |
| break; |
| case A_CLK1HZ: |
| now = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL); |
| r = counter_from_tickoff(now, s->clk1hz_tick_offset, 1); |
| break; |
| case A_CLK100HZ: |
| now = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL); |
| r = counter_from_tickoff(now, s->clk100hz_tick_offset, 100); |
| break; |
| case A_COUNTER: |
| resync_counter(s); |
| r = s->counter; |
| break; |
| case A_PSCNTR: |
| resync_counter(s); |
| r = s->pscntr; |
| break; |
| case A_SWITCH: |
| if (!s->has_switches) { |
| goto bad_offset; |
| } |
| /* User-togglable board switches. We don't model that, so report 0. */ |
| r = 0; |
| break; |
| default: |
| bad_offset: |
| qemu_log_mask(LOG_GUEST_ERROR, |
| "MPS2 FPGAIO read: bad offset %x\n", (int) offset); |
| r = 0; |
| break; |
| } |
| |
| trace_mps2_fpgaio_read(offset, r, size); |
| return r; |
| } |
| |
| static void mps2_fpgaio_write(void *opaque, hwaddr offset, uint64_t value, |
| unsigned size) |
| { |
| MPS2FPGAIO *s = MPS2_FPGAIO(opaque); |
| int64_t now; |
| |
| trace_mps2_fpgaio_write(offset, value, size); |
| |
| switch (offset) { |
| case A_LED0: |
| if (s->num_leds != 0) { |
| uint32_t i; |
| |
| s->led0 = value & MAKE_64BIT_MASK(0, s->num_leds); |
| for (i = 0; i < s->num_leds; i++) { |
| led_set_state(s->led[i], value & (1 << i)); |
| } |
| } |
| break; |
| case A_DBGCTRL: |
| if (!s->has_dbgctrl) { |
| goto bad_offset; |
| } |
| qemu_log_mask(LOG_UNIMP, |
| "MPS2 FPGAIO: DBGCTRL unimplemented\n"); |
| s->dbgctrl = value; |
| break; |
| case A_PRESCALE: |
| resync_counter(s); |
| s->prescale = value; |
| break; |
| case A_MISC: |
| /* These are control bits for some of the other devices on the |
| * board (SPI, CLCD, etc). We don't implement that yet, so just |
| * make the bits read as written. |
| */ |
| qemu_log_mask(LOG_UNIMP, |
| "MPS2 FPGAIO: MISC control bits unimplemented\n"); |
| s->misc = value; |
| break; |
| case A_CLK1HZ: |
| now = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL); |
| s->clk1hz_tick_offset = tickoff_from_counter(now, value, 1); |
| break; |
| case A_CLK100HZ: |
| now = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL); |
| s->clk100hz_tick_offset = tickoff_from_counter(now, value, 100); |
| break; |
| case A_COUNTER: |
| resync_counter(s); |
| s->counter = value; |
| break; |
| case A_PSCNTR: |
| resync_counter(s); |
| s->pscntr = value; |
| break; |
| default: |
| bad_offset: |
| qemu_log_mask(LOG_GUEST_ERROR, |
| "MPS2 FPGAIO write: bad offset 0x%x\n", (int) offset); |
| break; |
| } |
| } |
| |
| static const MemoryRegionOps mps2_fpgaio_ops = { |
| .read = mps2_fpgaio_read, |
| .write = mps2_fpgaio_write, |
| .endianness = DEVICE_LITTLE_ENDIAN, |
| }; |
| |
| static void mps2_fpgaio_reset(DeviceState *dev) |
| { |
| MPS2FPGAIO *s = MPS2_FPGAIO(dev); |
| int64_t now = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL); |
| |
| trace_mps2_fpgaio_reset(); |
| s->led0 = 0; |
| s->prescale = 0; |
| s->misc = 0; |
| s->clk1hz_tick_offset = tickoff_from_counter(now, 0, 1); |
| s->clk100hz_tick_offset = tickoff_from_counter(now, 0, 100); |
| s->counter = 0; |
| s->pscntr = 0; |
| s->pscntr_sync_ticks = now; |
| |
| for (size_t i = 0; i < s->num_leds; i++) { |
| device_cold_reset(DEVICE(s->led[i])); |
| } |
| } |
| |
| static void mps2_fpgaio_init(Object *obj) |
| { |
| SysBusDevice *sbd = SYS_BUS_DEVICE(obj); |
| MPS2FPGAIO *s = MPS2_FPGAIO(obj); |
| |
| memory_region_init_io(&s->iomem, obj, &mps2_fpgaio_ops, s, |
| "mps2-fpgaio", 0x1000); |
| sysbus_init_mmio(sbd, &s->iomem); |
| } |
| |
| static void mps2_fpgaio_realize(DeviceState *dev, Error **errp) |
| { |
| MPS2FPGAIO *s = MPS2_FPGAIO(dev); |
| uint32_t i; |
| |
| if (s->num_leds > MPS2FPGAIO_MAX_LEDS) { |
| error_setg(errp, "num-leds cannot be greater than %d", |
| MPS2FPGAIO_MAX_LEDS); |
| return; |
| } |
| |
| for (i = 0; i < s->num_leds; i++) { |
| g_autofree char *ledname = g_strdup_printf("USERLED%d", i); |
| s->led[i] = led_create_simple(OBJECT(dev), GPIO_POLARITY_ACTIVE_HIGH, |
| LED_COLOR_GREEN, ledname); |
| } |
| } |
| |
| static const VMStateDescription mps2_fpgaio_vmstate = { |
| .name = "mps2-fpgaio", |
| .version_id = 3, |
| .minimum_version_id = 3, |
| .fields = (VMStateField[]) { |
| VMSTATE_UINT32(led0, MPS2FPGAIO), |
| VMSTATE_UINT32(prescale, MPS2FPGAIO), |
| VMSTATE_UINT32(misc, MPS2FPGAIO), |
| VMSTATE_UINT32(dbgctrl, MPS2FPGAIO), |
| VMSTATE_INT64(clk1hz_tick_offset, MPS2FPGAIO), |
| VMSTATE_INT64(clk100hz_tick_offset, MPS2FPGAIO), |
| VMSTATE_UINT32(counter, MPS2FPGAIO), |
| VMSTATE_UINT32(pscntr, MPS2FPGAIO), |
| VMSTATE_INT64(pscntr_sync_ticks, MPS2FPGAIO), |
| VMSTATE_END_OF_LIST() |
| }, |
| }; |
| |
| static Property mps2_fpgaio_properties[] = { |
| /* Frequency of the prescale counter */ |
| DEFINE_PROP_UINT32("prescale-clk", MPS2FPGAIO, prescale_clk, 20000000), |
| /* Number of LEDs controlled by LED0 register */ |
| DEFINE_PROP_UINT32("num-leds", MPS2FPGAIO, num_leds, 2), |
| DEFINE_PROP_BOOL("has-switches", MPS2FPGAIO, has_switches, false), |
| DEFINE_PROP_BOOL("has-dbgctrl", MPS2FPGAIO, has_dbgctrl, false), |
| DEFINE_PROP_END_OF_LIST(), |
| }; |
| |
| static void mps2_fpgaio_class_init(ObjectClass *klass, void *data) |
| { |
| DeviceClass *dc = DEVICE_CLASS(klass); |
| |
| dc->vmsd = &mps2_fpgaio_vmstate; |
| dc->realize = mps2_fpgaio_realize; |
| dc->reset = mps2_fpgaio_reset; |
| device_class_set_props(dc, mps2_fpgaio_properties); |
| } |
| |
| static const TypeInfo mps2_fpgaio_info = { |
| .name = TYPE_MPS2_FPGAIO, |
| .parent = TYPE_SYS_BUS_DEVICE, |
| .instance_size = sizeof(MPS2FPGAIO), |
| .instance_init = mps2_fpgaio_init, |
| .class_init = mps2_fpgaio_class_init, |
| }; |
| |
| static void mps2_fpgaio_register_types(void) |
| { |
| type_register_static(&mps2_fpgaio_info); |
| } |
| |
| type_init(mps2_fpgaio_register_types); |