Re: [Qemu-devel] [V3,6/7] nios2: Add Altera 10M50 GHRD emulation

[Guenter Roeck]

On Tue, Oct 18, 2016 at 11:50:30PM +0200, Marek Vasut wrote:
> Add the Altera 10M50 Nios2 GHRD model. This allows emulating the
> 10M50 development kit with the Nios2 GHRD loaded in the FPGA. It
> is possible to boot Linux kernel and run userspace, thus far only
> from initrd as storage support is not yet implemented.
> 
> Signed-off-by: Marek Vasut <address@hidden>
> Cc: Chris Wulff <address@hidden>
> Cc: Jeff Da Silva <address@hidden>
> Cc: Ley Foon Tan <address@hidden>
> Cc: Sandra Loosemore <address@hidden>
> Cc: Yves Vandervennet <address@hidden>
> ---
> V3: Checkpatch cleanup, move cpu_pic.c here
> ---
>  hw/nios2/10m50_devboard.c | 126 ++++++++++++++++++++++++++
>  hw/nios2/Makefile.objs    |   1 +
>  hw/nios2/boot.c           | 223 
> ++++++++++++++++++++++++++++++++++++++++++++++
>  hw/nios2/boot.h           |  11 +++
>  hw/nios2/cpu_pic.c        |  70 +++++++++++++++
>  5 files changed, 431 insertions(+)
>  create mode 100644 hw/nios2/10m50_devboard.c
>  create mode 100644 hw/nios2/Makefile.objs
>  create mode 100644 hw/nios2/boot.c
>  create mode 100644 hw/nios2/boot.h
>  create mode 100644 hw/nios2/cpu_pic.c
> 
> diff --git a/hw/nios2/10m50_devboard.c b/hw/nios2/10m50_devboard.c
> new file mode 100644
> index 0000000..62e5738
> --- /dev/null
> +++ b/hw/nios2/10m50_devboard.c
> @@ -0,0 +1,126 @@
> +/*
> + * Altera 10M50 Nios2 GHRD
> + *
> + * Copyright (c) 2016 Marek Vasut <address@hidden>
> + *
> + * Based on LabX device code
> + *
> + * Copyright (c) 2012 Chris Wulff <address@hidden>
> + *
> + * This library is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU Lesser General Public
> + * License as published by the Free Software Foundation; either
> + * version 2.1 of the License, or (at your option) any later version.
> + *
> + * This library is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> + * Lesser General Public License for more details.
> + *
> + * You should have received a copy of the GNU Lesser General Public
> + * License along with this library; if not, see
> + * <http://www.gnu.org/licenses/lgpl-2.1.html>
> + */
> +
> +#include "qemu/osdep.h"
> +#include "qapi/error.h"
> +#include "qemu-common.h"
> +#include "cpu.h"
> +
> +#include "hw/sysbus.h"
> +#include "hw/hw.h"
> +#include "hw/char/serial.h"
> +#include "sysemu/sysemu.h"
> +#include "hw/boards.h"
> +#include "exec/memory.h"
> +#include "exec/address-spaces.h"
> +#include "qemu/config-file.h"
> +
> +#include "boot.h"
> +
> +#define BINARY_DEVICE_TREE_FILE    "10m50-devboard.dtb"
> +
> +static void nios2_10m50_ghrd_init(MachineState *machine)
> +{
> +    Nios2CPU *cpu;
> +    DeviceState *dev;
> +    MemoryRegion *address_space_mem = get_system_memory();
> +    MemoryRegion *phys_tcm = g_new(MemoryRegion, 1);
> +    MemoryRegion *phys_tcm_alias = g_new(MemoryRegion, 1);
> +    MemoryRegion *phys_ram = g_new(MemoryRegion, 1);
> +    MemoryRegion *phys_ram_alias = g_new(MemoryRegion, 1);
> +    ram_addr_t tcm_base = 0x0;
> +    ram_addr_t tcm_size = 0x1000;    /* 1 kiB, but QEMU limit is 4 kiB */
> +    ram_addr_t ram_base = 0x08000000;
> +    ram_addr_t ram_size = 0x08000000;
> +    qemu_irq *cpu_irq, irq[32];
> +    int i;
> +
> +    /* Physical TCM (tb_ram_1k) with alias at 0xc0000000 */
> +    memory_region_init_ram(phys_tcm, NULL, "nios2.tcm", tcm_size, 
> &error_abort);
> +    memory_region_init_alias(phys_tcm_alias, NULL, "nios2.tcm.alias",
> +                             phys_tcm, 0, tcm_size);
> +    vmstate_register_ram_global(phys_tcm);
> +    memory_region_add_subregion(address_space_mem, tcm_base, phys_tcm);
> +    memory_region_add_subregion(address_space_mem, 0xc0000000 + tcm_base,
> +                                phys_tcm_alias);
> +
> +    /* Physical DRAM with alias at 0xc0000000 */
> +    memory_region_init_ram(phys_ram, NULL, "nios2.ram", ram_size, 
> &error_abort);
> +    memory_region_init_alias(phys_ram_alias, NULL, "nios2.ram.alias",
> +                             phys_ram, 0, ram_size);
> +    vmstate_register_ram_global(phys_ram);
> +    memory_region_add_subregion(address_space_mem, ram_base, phys_ram);
> +    memory_region_add_subregion(address_space_mem, 0xc0000000 + ram_base,
> +                                phys_ram_alias);
> +
> +    /* Create CPU -- FIXME */
> +    cpu = cpu_nios2_init("nios2");
> +
> +    /* Register: CPU interrupt controller (PIC) */
> +    cpu_irq = nios2_cpu_pic_init(cpu);
> +
> +    /* Register: Internal Interrupt Controller (IIC) */
> +    dev = qdev_create(NULL, "altera,iic");
> +    qdev_prop_set_ptr(dev, "cpu", cpu);
> +    qdev_init_nofail(dev);
> +    sysbus_connect_irq(SYS_BUS_DEVICE(dev), 0, cpu_irq[0]);
> +    for (i = 0; i < 32; i++) {
> +        irq[i] = qdev_get_gpio_in(dev, i);
> +    }
> +
> +    /* Register: Altera 16550 UART */
> +    serial_mm_init(address_space_mem, 0xf8001600, 2, irq[1], 115200,
> +                   serial_hds[0], DEVICE_NATIVE_ENDIAN);
> +
> +    /* Register: Timer sys_clk_timer  */
> +    dev = qdev_create(NULL, "ALTR.timer");
> +    qdev_prop_set_uint32(dev, "clock-frequency", 75 * 1000000);
> +    qdev_init_nofail(dev);
> +    sysbus_mmio_map(SYS_BUS_DEVICE(dev), 0, 0xf8001440);
> +    sysbus_connect_irq(SYS_BUS_DEVICE(dev), 0, irq[0]);
> +
> +    /* Register: Timer sys_clk_timer_1  */
> +    dev = qdev_create(NULL, "ALTR.timer");
> +    qdev_prop_set_uint32(dev, "clock-frequency", 75 * 1000000);
> +    qdev_init_nofail(dev);
> +    sysbus_mmio_map(SYS_BUS_DEVICE(dev), 0, 0xe0000880);
> +    sysbus_connect_irq(SYS_BUS_DEVICE(dev), 0, irq[5]);
> +
> +    /* Configure new exception vectors and reset CPU for it to take effect. 
> */
> +    cpu->reset_addr = 0xd4000000;
> +    cpu->exception_addr = 0xc8000120;
> +    cpu->fast_tlb_miss_addr = 0xc0000100;
> +
> +    nios2_load_kernel(cpu, ram_base, ram_size, machine->initrd_filename,
> +                      BINARY_DEVICE_TREE_FILE, NULL);
> +}
> +
> +static void nios2_10m50_ghrd_machine_init(struct MachineClass *mc)
> +{
> +    mc->desc = "Altera 10M50 GHRD Nios II design";
> +    mc->init = nios2_10m50_ghrd_init;
> +    mc->is_default = 1;
> +}
> +
> +DEFINE_MACHINE("10m50-ghrd", nios2_10m50_ghrd_machine_init);
> diff --git a/hw/nios2/Makefile.objs b/hw/nios2/Makefile.objs
> new file mode 100644
> index 0000000..6b5c421
> --- /dev/null
> +++ b/hw/nios2/Makefile.objs
> @@ -0,0 +1 @@
> +obj-y = boot.o cpu_pic.o 10m50_devboard.o
> diff --git a/hw/nios2/boot.c b/hw/nios2/boot.c
> new file mode 100644
> index 0000000..564dbae
> --- /dev/null
> +++ b/hw/nios2/boot.c
> @@ -0,0 +1,223 @@
> +/*
> + * Nios2 kernel loader
> + *
> + * Copyright (c) 2016 Marek Vasut <address@hidden>
> + *
> + * Based on microblaze kernel loader
> + *
> + * Copyright (c) 2012 Peter Crosthwaite <address@hidden>
> + * Copyright (c) 2012 PetaLogix
> + * Copyright (c) 2009 Edgar E. Iglesias.
> + *
> + * 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 "qemu-common.h"
> +#include "cpu.h"
> +#include "qemu/option.h"
> +#include "qemu/config-file.h"
> +#include "qemu/error-report.h"
> +#include "qemu-common.h"
> +#include "sysemu/device_tree.h"
> +#include "sysemu/sysemu.h"
> +#include "hw/loader.h"
> +#include "elf.h"
> +#include "qemu/cutils.h"
> +
> +#include "boot.h"
> +
> +#define NIOS2_MAGIC    0x534f494e
> +
> +static struct nios2_boot_info {
> +    void (*machine_cpu_reset)(Nios2CPU *);
> +    uint32_t bootstrap_pc;
> +    uint32_t cmdline;
> +    uint32_t initrd_start;
> +    uint32_t initrd_end;
> +    uint32_t fdt;
> +} boot_info;
> +
> +static void main_cpu_reset(void *opaque)
> +{
> +    Nios2CPU *cpu = opaque;
> +    CPUState *cs = CPU(cpu);
> +    CPUNios2State *env = &cpu->env;
> +
> +    cpu_reset(CPU(cpu));
> +
> +    env->regs[R_ARG0] = NIOS2_MAGIC;
> +    env->regs[R_ARG1] = boot_info.initrd_start;
> +    env->regs[R_ARG2] = boot_info.fdt;
> +    env->regs[R_ARG3] = boot_info.cmdline;
> +
> +    cpu_set_pc(cs, boot_info.bootstrap_pc);
> +    if (boot_info.machine_cpu_reset) {
> +        boot_info.machine_cpu_reset(cpu);
> +    }
> +}
> +
> +static int nios2_load_dtb(struct nios2_boot_info bi, const uint32_t ramsize,
> +                          const char *kernel_cmdline, const char 
> *dtb_filename)
> +{
> +    int fdt_size;
> +    void *fdt = NULL;
> +    int r;
> +
> +    if (dtb_filename) {
> +        fdt = load_device_tree(dtb_filename, &fdt_size);
> +    }
> +    if (!fdt) {
> +        return 0;
> +    }
> +
> +    if (kernel_cmdline) {
> +        r = qemu_fdt_setprop_string(fdt, "/chosen", "bootargs",
> +                                    kernel_cmdline);
> +        if (r < 0) {
> +            fprintf(stderr, "couldn't set /chosen/bootargs\n");
> +        }
> +    }
> +
> +    if (bi.initrd_start) {
> +        qemu_fdt_setprop_cell(fdt, "/chosen", "linux,initrd-start",
> +                              bi.initrd_start);
> +
> +        qemu_fdt_setprop_cell(fdt, "/chosen", "linux,initrd-end",
> +                              bi.initrd_end);
> +    }

This doesn't work. The kernel assumes that those are physical addresses
and converts them into virtual addresses (see __early_init_dt_declare_initrd).
This changes the addresses from, say, 0xc8400000 to 0x88400000 (with the
default configuration).  However, the kernel code at the same time assumes
that the parameters passed in r5/r6 _are_ virtual addresses, and does not
convert them (see nios2_boot_init). The values are the same, though.
Result is that the kernel hangs if the devicetree file is passed to it
with the -dtb option (because the linux,initrd-start and linux,initrd-end
properties only exist in that case).

I can not really say if this is a kernel bug or a qemu bug or both.
All I can say is that the above doesn't work.

Another problem is seen when I try to reboot (running an initramfs generated
from busybox). This results in the following messages.

...
The system is going down NOW!
Sent SIGTERM to all processes
Sent SIGKILL to all processes
Requesting system reboot
reboot: Restarting system
Machine restart (d4000000)...
qemu-system-nios2: Trying to execute code outside RAM or ROM at 0xd4000000
This usually means one of the following happened:
...
Execution cannot continue; stopping here.

Thanks,
Guenter

> +
> +    cpu_physical_memory_write(bi.fdt, fdt, fdt_size);
> +    return fdt_size;
> +}
> +
> +static uint64_t translate_kernel_address(void *opaque, uint64_t addr)
> +{
> +    return addr - 0xc0000000LL;
> +}
> +
> +void nios2_load_kernel(Nios2CPU *cpu, hwaddr ddr_base,
> +                            uint32_t ramsize,
> +                            const char *initrd_filename,
> +                            const char *dtb_filename,
> +                            void (*machine_cpu_reset)(Nios2CPU *))
> +{
> +    QemuOpts *machine_opts;
> +    const char *kernel_filename;
> +    const char *kernel_cmdline;
> +    const char *dtb_arg;
> +    char *filename = NULL;
> +
> +    machine_opts = qemu_get_machine_opts();
> +    kernel_filename = qemu_opt_get(machine_opts, "kernel");
> +    kernel_cmdline = qemu_opt_get(machine_opts, "append");
> +    dtb_arg = qemu_opt_get(machine_opts, "dtb");
> +    /* default to pcbios dtb as passed by machine_init */
> +    if (!dtb_arg) {
> +        filename = qemu_find_file(QEMU_FILE_TYPE_BIOS, dtb_filename);
> +    }
> +
> +    boot_info.machine_cpu_reset = machine_cpu_reset;
> +    qemu_register_reset(main_cpu_reset, cpu);
> +
> +    if (kernel_filename) {
> +        int kernel_size, fdt_size;
> +        uint64_t entry, low, high;
> +        uint32_t base32;
> +        int big_endian = 0;
> +
> +#ifdef TARGET_WORDS_BIGENDIAN
> +        big_endian = 1;
> +#endif
> +
> +        /* Boots a kernel elf binary. */
> +        kernel_size = load_elf(kernel_filename, NULL, NULL,
> +                               &entry, &low, &high,
> +                               big_endian, EM_ALTERA_NIOS2, 0, 0);
> +        base32 = entry;
> +        if (base32 == 0xc0000000) {
> +            kernel_size = load_elf(kernel_filename, translate_kernel_address,
> +                                   NULL, &entry, NULL, NULL,
> +                                   big_endian, EM_ALTERA_NIOS2, 0, 0);
> +        }
> +
> +        /* Always boot into physical ram. */
> +        boot_info.bootstrap_pc = ddr_base + 0xc0000000 + (entry & 
> 0x07ffffff);
> +
> +        /* If it wasn't an ELF image, try an u-boot image. */
> +        if (kernel_size < 0) {
> +            hwaddr uentry, loadaddr;
> +
> +            kernel_size = load_uimage(kernel_filename, &uentry, &loadaddr, 0,
> +                                      NULL, NULL);
> +            boot_info.bootstrap_pc = uentry;
> +            high = loadaddr + kernel_size;
> +        }
> +
> +        /* Not an ELF image nor an u-boot image, try a RAW image. */
> +        if (kernel_size < 0) {
> +            kernel_size = load_image_targphys(kernel_filename, ddr_base,
> +                                              ram_size);
> +            boot_info.bootstrap_pc = ddr_base;
> +            high = ddr_base + kernel_size;
> +        }
> +
> +        high = ROUND_UP(high, 1024 * 1024);
> +
> +        /* If initrd is available, it goes after the kernel, aligned to 1M. 
> */
> +        if (initrd_filename) {
> +            int initrd_size;
> +            uint32_t initrd_offset;
> +
> +            boot_info.initrd_start = high;
> +            initrd_offset = boot_info.initrd_start - ddr_base;
> +
> +            initrd_size = load_ramdisk(initrd_filename,
> +                                       boot_info.initrd_start,
> +                                       ram_size - initrd_offset);
> +            if (initrd_size < 0) {
> +                initrd_size = load_image_targphys(initrd_filename,
> +                                                  boot_info.initrd_start,
> +                                                  ram_size - initrd_offset);
> +            }
> +            if (initrd_size < 0) {
> +                error_report("qemu: could not load initrd '%s'",
> +                             initrd_filename);
> +                exit(EXIT_FAILURE);
> +            }
> +            high += initrd_size;
> +        }
> +        high = ROUND_UP(high, 4);
> +        boot_info.initrd_end = high;
> +
> +        /* Device tree must be placed right after initrd (if available) */
> +        boot_info.fdt = high;
> +        fdt_size = nios2_load_dtb(boot_info, ram_size, kernel_cmdline,
> +                                  /* Preference a -dtb argument */
> +                                  dtb_arg ? dtb_arg : filename);
> +        high += fdt_size;
> +
> +        /* Kernel command is at the end, 4k aligned. */
> +        boot_info.cmdline = ROUND_UP(high, 4096);
> +        if (kernel_cmdline && strlen(kernel_cmdline)) {
> +            pstrcpy_targphys("cmdline", boot_info.cmdline, 256, 
> kernel_cmdline);
> +        }
> +    }
> +    g_free(filename);
> +}
> diff --git a/hw/nios2/boot.h b/hw/nios2/boot.h
> new file mode 100644
> index 0000000..3116753
> --- /dev/null
> +++ b/hw/nios2/boot.h
> @@ -0,0 +1,11 @@
> +#ifndef NIOS2_BOOT_H
> +#define NIOS2_BOOT_H
> +
> +#include "hw/hw.h"
> +#include "cpu.h"
> +
> +void nios2_load_kernel(Nios2CPU *cpu, hwaddr ddr_base, uint32_t ramsize,
> +                       const char *initrd_filename, const char *dtb_filename,
> +                       void (*machine_cpu_reset)(Nios2CPU *));
> +
> +#endif /* NIOS2_BOOT_H */
> diff --git a/hw/nios2/cpu_pic.c b/hw/nios2/cpu_pic.c
> new file mode 100644
> index 0000000..0f95987
> --- /dev/null
> +++ b/hw/nios2/cpu_pic.c
> @@ -0,0 +1,70 @@
> +/*
> + * Altera Nios2 CPU PIC
> + *
> + * Copyright (c) 2016 Marek Vasut <address@hidden>
> + *
> + * This library is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU Lesser General Public
> + * License as published by the Free Software Foundation; either
> + * version 2.1 of the License, or (at your option) any later version.
> + *
> + * This library is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> + * Lesser General Public License for more details.
> + *
> + * You should have received a copy of the GNU Lesser General Public
> + * License along with this library; if not, see
> + * <http://www.gnu.org/licenses/lgpl-2.1.html>
> + */
> +
> +#include "qemu/osdep.h"
> +#include "qapi/error.h"
> +#include "qemu-common.h"
> +#include "cpu.h"
> +
> +#include "qemu/config-file.h"
> +
> +#include "boot.h"
> +
> +static void nios2_pic_cpu_handler(void *opaque, int irq, int level)
> +{
> +    Nios2CPU *cpu = opaque;
> +    CPUNios2State *env = &cpu->env;
> +    CPUState *cs = CPU(cpu);
> +    int type = irq ? CPU_INTERRUPT_NMI : CPU_INTERRUPT_HARD;
> +
> +    if (type == CPU_INTERRUPT_HARD) {
> +        env->irq_pending = level;
> +
> +        if (level && (env->regs[CR_STATUS] & CR_STATUS_PIE)) {
> +            env->irq_pending = 0;
> +            cpu_interrupt(cs, type);
> +        } else if (!level) {
> +            env->irq_pending = 0;
> +            cpu_reset_interrupt(cs, type);
> +        }
> +    } else {
> +        if (level) {
> +            cpu_interrupt(cs, type);
> +        } else {
> +            cpu_reset_interrupt(cs, type);
> +        }
> +    }
> +}
> +
> +void nios2_check_interrupts(CPUNios2State *env)
> +{
> +    Nios2CPU *cpu = nios2_env_get_cpu(env);
> +    CPUState *cs = CPU(cpu);
> +
> +    if (env->irq_pending) {
> +        env->irq_pending = 0;
> +        cpu_interrupt(cs, CPU_INTERRUPT_HARD);
> +    }
> +}
> +
> +qemu_irq *nios2_cpu_pic_init(Nios2CPU *cpu)
> +{
> +    return qemu_allocate_irqs(nios2_pic_cpu_handler, cpu, 2);
> +}