diff options
Diffstat (limited to 'hw/intc/nios2_vic.c')
-rw-r--r-- | hw/intc/nios2_vic.c | 313 |
1 files changed, 313 insertions, 0 deletions
diff --git a/hw/intc/nios2_vic.c b/hw/intc/nios2_vic.c new file mode 100644 index 0000000000..cf63212a88 --- /dev/null +++ b/hw/intc/nios2_vic.c @@ -0,0 +1,313 @@ +/* + * Vectored Interrupt Controller for nios2 processor + * + * Copyright (c) 2022 Neuroblade + * + * Interface: + * QOM property "cpu": link to the Nios2 CPU (must be set) + * Unnamed GPIO inputs 0..NIOS2_VIC_MAX_IRQ-1: input IRQ lines + * IRQ should be connected to nios2 IRQ0. + * + * Reference: "Embedded Peripherals IP User Guide + * for Intel® Quartus® Prime Design Suite: 21.4" + * Chapter 38 "Vectored Interrupt Controller Core" + * See: https://www.intel.com/content/www/us/en/docs/programmable/683130/21-4/vectored-interrupt-controller-core.html + * + * Permission is hereby granted, free of charge, to any person obtaining a copy + * of this software and associated documentation files (the "Software"), to deal + * in the Software without restriction, including without limitation the rights + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell + * copies of the Software, and to permit persons to whom the Software is + * furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice shall be included in + * all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN + * THE SOFTWARE. + */ + +#include "qemu/osdep.h" + +#include "hw/irq.h" +#include "hw/qdev-properties.h" +#include "hw/sysbus.h" +#include "migration/vmstate.h" +#include "qapi/error.h" +#include "qemu/bitops.h" +#include "qemu/log.h" +#include "qom/object.h" +#include "hw/intc/nios2_vic.h" +#include "cpu.h" + + +enum { + INT_CONFIG0 = 0, + INT_CONFIG31 = 31, + INT_ENABLE = 32, + INT_ENABLE_SET = 33, + INT_ENABLE_CLR = 34, + INT_PENDING = 35, + INT_RAW_STATUS = 36, + SW_INTERRUPT = 37, + SW_INTERRUPT_SET = 38, + SW_INTERRUPT_CLR = 39, + VIC_CONFIG = 40, + VIC_STATUS = 41, + VEC_TBL_BASE = 42, + VEC_TBL_ADDR = 43, + CSR_COUNT /* Last! */ +}; + +/* Requested interrupt level (INT_CONFIG[0:5]) */ +static inline uint32_t vic_int_config_ril(const Nios2VIC *vic, int irq_num) +{ + return extract32(vic->int_config[irq_num], 0, 6); +} + +/* Requested NMI (INT_CONFIG[6]) */ +static inline uint32_t vic_int_config_rnmi(const Nios2VIC *vic, int irq_num) +{ + return extract32(vic->int_config[irq_num], 6, 1); +} + +/* Requested register set (INT_CONFIG[7:12]) */ +static inline uint32_t vic_int_config_rrs(const Nios2VIC *vic, int irq_num) +{ + return extract32(vic->int_config[irq_num], 7, 6); +} + +static inline uint32_t vic_config_vec_size(const Nios2VIC *vic) +{ + return 1 << (2 + extract32(vic->vic_config, 0, 3)); +} + +static inline uint32_t vic_int_pending(const Nios2VIC *vic) +{ + return (vic->int_raw_status | vic->sw_int) & vic->int_enable; +} + +static void vic_update_irq(Nios2VIC *vic) +{ + Nios2CPU *cpu = NIOS2_CPU(vic->cpu); + uint32_t pending = vic_int_pending(vic); + int irq = -1; + int max_ril = 0; + /* Note that if RIL is 0 for an interrupt it is effectively disabled */ + + vic->vec_tbl_addr = 0; + vic->vic_status = 0; + + if (pending == 0) { + qemu_irq_lower(vic->output_int); + return; + } + + for (int i = 0; i < NIOS2_VIC_MAX_IRQ; i++) { + if (pending & BIT(i)) { + int ril = vic_int_config_ril(vic, i); + if (ril > max_ril) { + irq = i; + max_ril = ril; + } + } + } + + if (irq < 0) { + qemu_irq_lower(vic->output_int); + return; + } + + vic->vec_tbl_addr = irq * vic_config_vec_size(vic) + vic->vec_tbl_base; + vic->vic_status = irq | BIT(31); + + /* + * In hardware, the interface between the VIC and the CPU is via the + * External Interrupt Controller interface, where the interrupt controller + * presents the CPU with a packet of data containing: + * - Requested Handler Address (RHA): 32 bits + * - Requested Register Set (RRS) : 6 bits + * - Requested Interrupt Level (RIL) : 6 bits + * - Requested NMI flag (RNMI) : 1 bit + * In our emulation, we implement this by writing the data directly to + * fields in the CPU object and then raising the IRQ line to tell + * the CPU that we've done so. + */ + + cpu->rha = vic->vec_tbl_addr; + cpu->ril = max_ril; + cpu->rrs = vic_int_config_rrs(vic, irq); + cpu->rnmi = vic_int_config_rnmi(vic, irq); + + qemu_irq_raise(vic->output_int); +} + +static void vic_set_irq(void *opaque, int irq_num, int level) +{ + Nios2VIC *vic = opaque; + + vic->int_raw_status = deposit32(vic->int_raw_status, irq_num, 1, !!level); + vic_update_irq(vic); +} + +static void nios2_vic_reset(DeviceState *dev) +{ + Nios2VIC *vic = NIOS2_VIC(dev); + + memset(&vic->int_config, 0, sizeof(vic->int_config)); + vic->vic_config = 0; + vic->int_raw_status = 0; + vic->int_enable = 0; + vic->sw_int = 0; + vic->vic_status = 0; + vic->vec_tbl_base = 0; + vic->vec_tbl_addr = 0; +} + +static uint64_t nios2_vic_csr_read(void *opaque, hwaddr offset, unsigned size) +{ + Nios2VIC *vic = opaque; + int index = offset / 4; + + switch (index) { + case INT_CONFIG0 ... INT_CONFIG31: + return vic->int_config[index - INT_CONFIG0]; + case INT_ENABLE: + return vic->int_enable; + case INT_PENDING: + return vic_int_pending(vic); + case INT_RAW_STATUS: + return vic->int_raw_status; + case SW_INTERRUPT: + return vic->sw_int; + case VIC_CONFIG: + return vic->vic_config; + case VIC_STATUS: + return vic->vic_status; + case VEC_TBL_BASE: + return vic->vec_tbl_base; + case VEC_TBL_ADDR: + return vic->vec_tbl_addr; + default: + return 0; + } +} + +static void nios2_vic_csr_write(void *opaque, hwaddr offset, uint64_t value, + unsigned size) +{ + Nios2VIC *vic = opaque; + int index = offset / 4; + + switch (index) { + case INT_CONFIG0 ... INT_CONFIG31: + vic->int_config[index - INT_CONFIG0] = value; + break; + case INT_ENABLE: + vic->int_enable = value; + break; + case INT_ENABLE_SET: + vic->int_enable |= value; + break; + case INT_ENABLE_CLR: + vic->int_enable &= ~value; + break; + case SW_INTERRUPT: + vic->sw_int = value; + break; + case SW_INTERRUPT_SET: + vic->sw_int |= value; + break; + case SW_INTERRUPT_CLR: + vic->sw_int &= ~value; + break; + case VIC_CONFIG: + vic->vic_config = value; + break; + case VEC_TBL_BASE: + vic->vec_tbl_base = value; + break; + default: + qemu_log_mask(LOG_GUEST_ERROR, + "nios2-vic: write to invalid CSR address %#" + HWADDR_PRIx "\n", offset); + } + + vic_update_irq(vic); +} + +static const MemoryRegionOps nios2_vic_csr_ops = { + .read = nios2_vic_csr_read, + .write = nios2_vic_csr_write, + .endianness = DEVICE_LITTLE_ENDIAN, + .valid = { .min_access_size = 4, .max_access_size = 4 } +}; + +static void nios2_vic_realize(DeviceState *dev, Error **errp) +{ + Nios2VIC *vic = NIOS2_VIC(dev); + + if (!vic->cpu) { + /* This is a programming error in the code using this device */ + error_setg(errp, "nios2-vic 'cpu' link property was not set"); + return; + } + + sysbus_init_irq(SYS_BUS_DEVICE(dev), &vic->output_int); + qdev_init_gpio_in(dev, vic_set_irq, NIOS2_VIC_MAX_IRQ); + + memory_region_init_io(&vic->csr, OBJECT(dev), &nios2_vic_csr_ops, vic, + "nios2.vic.csr", CSR_COUNT * sizeof(uint32_t)); + sysbus_init_mmio(SYS_BUS_DEVICE(dev), &vic->csr); +} + +static Property nios2_vic_properties[] = { + DEFINE_PROP_LINK("cpu", Nios2VIC, cpu, TYPE_CPU, CPUState *), + DEFINE_PROP_END_OF_LIST() +}; + +static const VMStateDescription nios2_vic_vmstate = { + .name = "nios2-vic", + .version_id = 1, + .minimum_version_id = 1, + .fields = (VMStateField[]){ + VMSTATE_UINT32_ARRAY(int_config, Nios2VIC, 32), + VMSTATE_UINT32(vic_config, Nios2VIC), + VMSTATE_UINT32(int_raw_status, Nios2VIC), + VMSTATE_UINT32(int_enable, Nios2VIC), + VMSTATE_UINT32(sw_int, Nios2VIC), + VMSTATE_UINT32(vic_status, Nios2VIC), + VMSTATE_UINT32(vec_tbl_base, Nios2VIC), + VMSTATE_UINT32(vec_tbl_addr, Nios2VIC), + VMSTATE_END_OF_LIST() + }, +}; + +static void nios2_vic_class_init(ObjectClass *klass, void *data) +{ + DeviceClass *dc = DEVICE_CLASS(klass); + + dc->reset = nios2_vic_reset; + dc->realize = nios2_vic_realize; + dc->vmsd = &nios2_vic_vmstate; + device_class_set_props(dc, nios2_vic_properties); +} + +static const TypeInfo nios2_vic_info = { + .name = TYPE_NIOS2_VIC, + .parent = TYPE_SYS_BUS_DEVICE, + .instance_size = sizeof(Nios2VIC), + .class_init = nios2_vic_class_init, +}; + +static void nios2_vic_register_types(void) +{ + type_register_static(&nios2_vic_info); +} + +type_init(nios2_vic_register_types); |