diff options
| -rw-r--r-- | MAINTAINERS | 5 | ||||
| -rw-r--r-- | default-configs/pci.mak | 1 | ||||
| -rw-r--r-- | docs/specs/edu.txt | 110 | ||||
| -rw-r--r-- | hw/misc/Makefile.objs | 1 | ||||
| -rw-r--r-- | hw/misc/edu.c | 408 |
5 files changed, 525 insertions, 0 deletions
diff --git a/MAINTAINERS b/MAINTAINERS index 430688d..fd335a4 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -599,6 +599,11 @@ F: hw/net/opencores_eth.c Devices ------- +EDU +M: Jiri Slaby <jslaby@suse.cz> +S: Maintained +F: hw/misc/edu.c + IDE M: Kevin Wolf <kwolf@redhat.com> M: Stefan Hajnoczi <stefanha@redhat.com> diff --git a/default-configs/pci.mak b/default-configs/pci.mak index a186c39..030cdc7 100644 --- a/default-configs/pci.mak +++ b/default-configs/pci.mak @@ -32,3 +32,4 @@ CONFIG_PCI_TESTDEV=y CONFIG_NVME_PCI=y CONFIG_SD=y CONFIG_SDHCI=y +CONFIG_EDU=y diff --git a/docs/specs/edu.txt b/docs/specs/edu.txt new file mode 100644 index 0000000..7f81467 --- /dev/null +++ b/docs/specs/edu.txt @@ -0,0 +1,110 @@ + +EDU device +========== + +Copyright (c) 2014-2015 Jiri Slaby + +This document is licensed under the GPLv2 (or later). + +This is an educational device for writing (kernel) drivers. Its original +intention was to support the Linux kernel lectures taught at the Masaryk +University. Students are given this virtual device and are expected to write a +driver with I/Os, IRQs, DMAs and such. + +The devices behaves very similar to the PCI bridge present in the COMBO6 cards +developed under the Liberouter wings. Both PCI device ID and PCI space is +inherited from that device. + +Command line switches: + -device edu[,dma_mask=mask] + + dma_mask makes the virtual device work with DMA addresses with the given + mask. For educational purposes, the device supports only 28 bits (256 MiB) + by default. Students shall set dma_mask for the device in the OS driver + properly. + +PCI specs +--------- + +PCI ID: 1234:11e8 + +PCI Region 0: + I/O memory, 1 MB in size. Users are supposed to communicate with the card + through this memory. + +MMIO area spec +-------------- + +Only size == 4 accesses are allowed for addresses < 0x80. size == 4 or +size == 8 for the rest. + +0x00 (RO) : identification (0xRRrr00edu) + RR -- major version + rr -- minor version + +0x04 (RW) : card liveness check + It is a simple value inversion (~ C operator). + +0x08 (RW) : factorial computation + The stored value is taken and factorial of it is put back here. + This happens only after factorial bit in the status register (0x20 + below) is cleared. + +0x20 (RW) : status register, bitwise OR + 0x01 -- computing factorial (RO) + 0x80 -- raise interrupt 0x01 after finishing factorial computation + +0x24 (RO) : interrupt status register + It contains values which raised the interrupt (see interrupt raise + register below). + +0x60 (WO) : interrupt raise register + Raise an interrupt. The value will be put to the interrupt status + register (using bitwise OR). + +0x64 (WO) : interrupt acknowledge register + Clear an interrupt. The value will be cleared from the interrupt + status register. This needs to be done from the ISR to stop + generating interrupts. + +0x80 (RW) : DMA source address + Where to perform the DMA from. + +0x88 (RW) : DMA destination address + Where to perform the DMA to. + +0x90 (RW) : DMA transfer count + The size of the area to perform the DMA on. + +0x98 (RW) : DMA command register, bitwise OR + 0x01 -- start transfer + 0x02 -- direction (0: from RAM to EDU, 1: from EDU to RAM) + 0x04 -- raise interrupt 0x100 after finishing the DMA + +IRQ controller +-------------- +An IRQ is generated when written to the interrupt raise register. The value +appears in interrupt status register when the interrupt is raised and has to +be written to the interrupt acknowledge register to lower it. + +DMA controller +-------------- +One has to specify, source, destination, size, and start the transfer. One +4096 bytes long buffer at offset 0x40000 is available in the EDU device. I.e. +one can perform DMA to/from this space when programmed properly. + +Example of transferring a 100 byte block to and from the buffer using a given +PCI address 'addr': +addr -> DMA source address +0x40000 -> DMA destination address +100 -> DMA transfer count +1 -> DMA command register +while (DMA command register & 1) + ; + +0x40000 -> DMA source address +addr+100 -> DMA destination address +100 -> DMA transfer count +3 -> DMA command register +while (DMA command register & 1) + ; diff --git a/hw/misc/Makefile.objs b/hw/misc/Makefile.objs index e47fea8..029a56f 100644 --- a/hw/misc/Makefile.objs +++ b/hw/misc/Makefile.objs @@ -40,3 +40,4 @@ obj-$(CONFIG_SLAVIO) += slavio_misc.o obj-$(CONFIG_ZYNQ) += zynq_slcr.o obj-$(CONFIG_PVPANIC) += pvpanic.o +obj-$(CONFIG_EDU) += edu.o diff --git a/hw/misc/edu.c b/hw/misc/edu.c new file mode 100644 index 0000000..f601069 --- /dev/null +++ b/hw/misc/edu.c @@ -0,0 +1,408 @@ +/* + * QEMU educational PCI device + * + * Copyright (c) 2012-2015 Jiri Slaby + * + * 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 "hw/pci/pci.h" +#include "qemu/timer.h" +#include "qemu/main-loop.h" /* iothread mutex */ +#include "qapi/visitor.h" + +#define EDU(obj) OBJECT_CHECK(EduState, obj, "edu") + +#define FACT_IRQ 0x00000001 +#define DMA_IRQ 0x00000100 + +#define DMA_START 0x40000 +#define DMA_SIZE 4096 + +typedef struct { + PCIDevice pdev; + MemoryRegion mmio; + + QemuThread thread; + QemuMutex thr_mutex; + QemuCond thr_cond; + bool stopping; + + uint32_t addr4; + uint32_t fact; +#define EDU_STATUS_COMPUTING 0x01 +#define EDU_STATUS_IRQFACT 0x80 + uint32_t status; + + uint32_t irq_status; + +#define EDU_DMA_RUN 0x1 +#define EDU_DMA_DIR(cmd) (((cmd) & 0x2) >> 1) +# define EDU_DMA_FROM_PCI 0 +# define EDU_DMA_TO_PCI 1 +#define EDU_DMA_IRQ 0x4 + struct dma_state { + dma_addr_t src; + dma_addr_t dst; + dma_addr_t cnt; + dma_addr_t cmd; + } dma; + QEMUTimer dma_timer; + char dma_buf[DMA_SIZE]; + uint64_t dma_mask; +} EduState; + +static void edu_raise_irq(EduState *edu, uint32_t val) +{ + edu->irq_status |= val; + if (edu->irq_status) { + pci_set_irq(&edu->pdev, 1); + } +} + +static void edu_lower_irq(EduState *edu, uint32_t val) +{ + edu->irq_status &= ~val; + + if (!edu->irq_status) { + pci_set_irq(&edu->pdev, 0); + } +} + +static bool within(uint32_t addr, uint32_t start, uint32_t end) +{ + return start <= addr && addr < end; +} + +static void edu_check_range(uint32_t addr, uint32_t size1, uint32_t start, + uint32_t size2) +{ + uint32_t end1 = addr + size1; + uint32_t end2 = start + size2; + + if (within(addr, start, end2) && + end1 > addr && within(end1, start, end2)) { + return; + } + + hw_error("EDU: DMA range 0x%.8x-0x%.8x out of bounds (0x%.8x-0x%.8x)!", + addr, end1 - 1, start, end2 - 1); +} + +static dma_addr_t edu_clamp_addr(const EduState *edu, dma_addr_t addr) +{ + dma_addr_t res = addr & edu->dma_mask; + + if (addr != res) { + printf("EDU: clamping DMA %#.16"PRIx64" to %#.16"PRIx64"!\n", addr, res); + } + + return res; +} + +static void edu_dma_timer(void *opaque) +{ + EduState *edu = opaque; + bool raise_irq = false; + + if (!(edu->dma.cmd & EDU_DMA_RUN)) { + return; + } + + if (EDU_DMA_DIR(edu->dma.cmd) == EDU_DMA_FROM_PCI) { + uint32_t dst = edu->dma.dst; + edu_check_range(dst, edu->dma.cnt, DMA_START, DMA_SIZE); + dst -= DMA_START; + pci_dma_read(&edu->pdev, edu_clamp_addr(edu, edu->dma.src), + edu->dma_buf + dst, edu->dma.cnt); + } else { + uint32_t src = edu->dma.src; + edu_check_range(src, edu->dma.cnt, DMA_START, DMA_SIZE); + src -= DMA_START; + pci_dma_write(&edu->pdev, edu_clamp_addr(edu, edu->dma.dst), + edu->dma_buf + src, edu->dma.cnt); + } + + edu->dma.cmd &= ~EDU_DMA_RUN; + if (edu->dma.cmd & EDU_DMA_IRQ) { + raise_irq = true; + } + + if (raise_irq) { + edu_raise_irq(edu, DMA_IRQ); + } +} + +static void dma_rw(EduState *edu, bool write, dma_addr_t *val, dma_addr_t *dma, + bool timer) +{ + if (write && (edu->dma.cmd & EDU_DMA_RUN)) { + return; + } + + if (write) { + *dma = *val; + } else { + *val = *dma; + } + + if (timer) { + timer_mod(&edu->dma_timer, qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) + 100); + } +} + +static uint64_t edu_mmio_read(void *opaque, hwaddr addr, unsigned size) +{ + EduState *edu = opaque; + uint64_t val = ~0ULL; + + if (size != 4) { + return val; + } + + switch (addr) { + case 0x00: + val = 0x010000edu; + break; + case 0x04: + val = edu->addr4; + break; + case 0x08: + qemu_mutex_lock(&edu->thr_mutex); + val = edu->fact; + qemu_mutex_unlock(&edu->thr_mutex); + break; + case 0x20: + val = atomic_read(&edu->status); + break; + case 0x24: + val = edu->irq_status; + break; + case 0x80: + dma_rw(edu, false, &val, &edu->dma.src, false); + break; + case 0x88: + dma_rw(edu, false, &val, &edu->dma.dst, false); + break; + case 0x90: + dma_rw(edu, false, &val, &edu->dma.cnt, false); + break; + case 0x98: + dma_rw(edu, false, &val, &edu->dma.cmd, false); + break; + } + + return val; +} + +static void edu_mmio_write(void *opaque, hwaddr addr, uint64_t val, + unsigned size) +{ + EduState *edu = opaque; + + if (addr < 0x80 && size != 4) { + return; + } + + if (addr >= 0x80 && size != 4 && size != 8) { + return; + } + + switch (addr) { + case 0x04: + edu->addr4 = ~val; + break; + case 0x08: + if (atomic_read(&edu->status) & EDU_STATUS_COMPUTING) { + break; + } + /* EDU_STATUS_COMPUTING cannot go 0->1 concurrently, because it is only + * set in this function and it is under the iothread mutex. + */ + qemu_mutex_lock(&edu->thr_mutex); + edu->fact = val; + atomic_or(&edu->status, EDU_STATUS_COMPUTING); + qemu_cond_signal(&edu->thr_cond); + qemu_mutex_unlock(&edu->thr_mutex); + break; + case 0x20: + if (val & EDU_STATUS_IRQFACT) { + atomic_or(&edu->status, EDU_STATUS_IRQFACT); + } else { + atomic_and(&edu->status, ~EDU_STATUS_IRQFACT); + } + break; + case 0x60: + edu_raise_irq(edu, val); + break; + case 0x64: + edu_lower_irq(edu, val); + break; + case 0x80: + dma_rw(edu, true, &val, &edu->dma.src, false); + break; + case 0x88: + dma_rw(edu, true, &val, &edu->dma.dst, false); + break; + case 0x90: + dma_rw(edu, true, &val, &edu->dma.cnt, false); + break; + case 0x98: + if (!(val & EDU_DMA_RUN)) { + break; + } + dma_rw(edu, true, &val, &edu->dma.cmd, true); + break; + } +} + +static const MemoryRegionOps edu_mmio_ops = { + .read = edu_mmio_read, + .write = edu_mmio_write, + .endianness = DEVICE_NATIVE_ENDIAN, +}; + +/* + * We purposedly use a thread, so that users are forced to wait for the status + * register. + */ +static void *edu_fact_thread(void *opaque) +{ + EduState *edu = opaque; + + while (1) { + uint32_t val, ret = 1; + + qemu_mutex_lock(&edu->thr_mutex); + while ((atomic_read(&edu->status) & EDU_STATUS_COMPUTING) == 0 && + !edu->stopping) { + qemu_cond_wait(&edu->thr_cond, &edu->thr_mutex); + } + + if (edu->stopping) { + qemu_mutex_unlock(&edu->thr_mutex); + break; + } + + val = edu->fact; + qemu_mutex_unlock(&edu->thr_mutex); + + while (val > 0) { + ret *= val--; + } + + /* + * We should sleep for a random period here, so that students are + * forced to check the status properly. + */ + + qemu_mutex_lock(&edu->thr_mutex); + edu->fact = ret; + qemu_mutex_unlock(&edu->thr_mutex); + atomic_and(&edu->status, ~EDU_STATUS_COMPUTING); + + if (atomic_read(&edu->status) & EDU_STATUS_IRQFACT) { + qemu_mutex_lock_iothread(); + edu_raise_irq(edu, FACT_IRQ); + qemu_mutex_unlock_iothread(); + } + } + + return NULL; +} + +static int pci_edu_init(PCIDevice *pdev) +{ + EduState *edu = DO_UPCAST(EduState, pdev, pdev); + uint8_t *pci_conf = pdev->config; + + timer_init_ms(&edu->dma_timer, QEMU_CLOCK_VIRTUAL, edu_dma_timer, edu); + + qemu_mutex_init(&edu->thr_mutex); + qemu_cond_init(&edu->thr_cond); + qemu_thread_create(&edu->thread, "edu", edu_fact_thread, + edu, QEMU_THREAD_JOINABLE); + + pci_config_set_interrupt_pin(pci_conf, 1); + + memory_region_init_io(&edu->mmio, OBJECT(edu), &edu_mmio_ops, edu, + "edu-mmio", 1 << 20); + pci_register_bar(pdev, 0, PCI_BASE_ADDRESS_SPACE_MEMORY, &edu->mmio); + + return 0; +} + +static void pci_edu_uninit(PCIDevice *pdev) +{ + EduState *edu = DO_UPCAST(EduState, pdev, pdev); + + qemu_mutex_lock(&edu->thr_mutex); + edu->stopping = true; + qemu_mutex_unlock(&edu->thr_mutex); + qemu_cond_signal(&edu->thr_cond); + qemu_thread_join(&edu->thread); + + qemu_cond_destroy(&edu->thr_cond); + qemu_mutex_destroy(&edu->thr_mutex); + + timer_del(&edu->dma_timer); +} + +static void edu_obj_uint64(Object *obj, struct Visitor *v, void *opaque, + const char *name, Error **errp) +{ + uint64_t *val = opaque; + + visit_type_uint64(v, val, name, errp); +} + +static void edu_instance_init(Object *obj) +{ + EduState *edu = EDU(obj); + + edu->dma_mask = (1UL << 28) - 1; + object_property_add(obj, "dma_mask", "uint64", edu_obj_uint64, + edu_obj_uint64, NULL, &edu->dma_mask, NULL); +} + +static void edu_class_init(ObjectClass *class, void *data) +{ + PCIDeviceClass *k = PCI_DEVICE_CLASS(class); + + k->init = pci_edu_init; + k->exit = pci_edu_uninit; + k->vendor_id = PCI_VENDOR_ID_QEMU; + k->device_id = 0x11e8; + k->revision = 0x10; + k->class_id = PCI_CLASS_OTHERS; +} + +static void pci_edu_register_types(void) +{ + static const TypeInfo edu_info = { + .name = "edu", + .parent = TYPE_PCI_DEVICE, + .instance_size = sizeof(EduState), + .instance_init = edu_instance_init, + .class_init = edu_class_init, + }; + + type_register_static(&edu_info); +} +type_init(pci_edu_register_types) |