Re: [Qemu-devel] [PATCH 4/4] arm: add device tree support

[Peter Maydell]

Ping re patch 3 and 4 here -- I know there was some discussion under the
thread on Peter Crosthwaite's 'qomify arm_boot' patch series, but it's a
bit hard to disentangle from the comments on that patch series.

Specifically, does anybody (a) dislike the user-facing command line
interface here or (b) otherwise think it's misguided? I'm not a huge
fan of the -machine options (they seem to be a bit of a grab-bag of
stuff) but I can live with them as a mechanism for passing the data
to the right place...

thanks
-- PMM

On 8 February 2012 05:41, Peter Maydell <address@hidden> wrote:
> From: Grant Likely <address@hidden>
>
> If compiled with CONFIG_FDT, allow user to specify a device tree file using
> the -dtb argument.  If the machine supports it then the dtb will be loaded
> into memory and passed to the kernel on boot.
>
> Signed-off-by: Jeremy Kerr <address@hidden>
> Signed-off-by: Grant Likely <address@hidden>
> [Peter Maydell: Use machine opt rather than global to pass dtb filename]
> Signed-off-by: Peter Maydell <address@hidden>
> ---
>  Makefile.target |    1 +
>  configure       |    1 +
>  hw/arm-misc.h   |    1 +
>  hw/arm_boot.c   |   96 +++++++++++++++++++++++++++++++++++++++++++++++++++---
>  qemu-config.c   |    4 ++
>  qemu-options.hx |    9 +++++
>  vl.c            |    9 +++++
>  7 files changed, 115 insertions(+), 6 deletions(-)
>
> diff --git a/Makefile.target b/Makefile.target
> index 68481a3..5e465ec 100644
> --- a/Makefile.target
> +++ b/Makefile.target
> @@ -363,6 +363,7 @@ obj-arm-y += vexpress.o
>  obj-arm-y += strongarm.o
>  obj-arm-y += collie.o
>  obj-arm-y += pl041.o lm4549.o
> +obj-arm-$(CONFIG_FDT) += device_tree.o
>
>  obj-sh4-y = shix.o r2d.o sh7750.o sh7750_regnames.o tc58128.o
>  obj-sh4-y += sh_timer.o sh_serial.o sh_intc.o sh_pci.o sm501.o
> diff --git a/configure b/configure
> index 763db24..1d8b3ac 100755
> --- a/configure
> +++ b/configure
> @@ -3458,6 +3458,7 @@ case "$target_arch2" in
>     gdb_xml_files="arm-core.xml arm-vfp.xml arm-vfp3.xml arm-neon.xml"
>     target_phys_bits=32
>     target_llong_alignment=4
> +    target_libs_softmmu="$fdt_libs"
>   ;;
>   cris)
>     target_nptl="yes"
> diff --git a/hw/arm-misc.h b/hw/arm-misc.h
> index 5e5204b..4b55fb8 100644
> --- a/hw/arm-misc.h
> +++ b/hw/arm-misc.h
> @@ -29,6 +29,7 @@ struct arm_boot_info {
>     const char *kernel_filename;
>     const char *kernel_cmdline;
>     const char *initrd_filename;
> +    const char *dtb_filename;
>     target_phys_addr_t loader_start;
>     /* multicore boards that use the default secondary core boot functions
>      * need to put the address of the secondary boot code, the boot reg,
> diff --git a/hw/arm_boot.c b/hw/arm_boot.c
> index 5f163fd..769fe2e 100644
> --- a/hw/arm_boot.c
> +++ b/hw/arm_boot.c
> @@ -7,11 +7,14 @@
>  * This code is licensed under the GPL.
>  */
>
> +#include "config.h"
>  #include "hw.h"
>  #include "arm-misc.h"
>  #include "sysemu.h"
> +#include "boards.h"
>  #include "loader.h"
>  #include "elf.h"
> +#include "device_tree.h"
>
>  #define KERNEL_ARGS_ADDR 0x100
>  #define KERNEL_LOAD_ADDR 0x00010000
> @@ -207,6 +210,67 @@ static void set_kernel_args_old(const struct 
> arm_boot_info *info,
>     }
>  }
>
> +static int load_dtb(target_phys_addr_t addr, const struct arm_boot_info 
> *binfo)
> +{
> +#ifdef CONFIG_FDT
> +    uint32_t mem_reg_property[] = { cpu_to_be32(binfo->loader_start),
> +                                    cpu_to_be32(binfo->ram_size) };
> +    void *fdt = NULL;
> +    char *filename;
> +    int size, rc;
> +
> +    filename = qemu_find_file(QEMU_FILE_TYPE_BIOS, binfo->dtb_filename);
> +    if (!filename) {
> +        fprintf(stderr, "Couldn't open dtb file %s\n", binfo->dtb_filename);
> +        return -1;
> +    }
> +
> +    fdt = load_device_tree(filename, &size);
> +    if (!fdt) {
> +        fprintf(stderr, "Couldn't open dtb file %s\n", filename);
> +        g_free(filename);
> +        return -1;
> +    }
> +    g_free(filename);
> +
> +    rc = qemu_devtree_setprop(fdt, "/memory", "reg", mem_reg_property,
> +                               sizeof(mem_reg_property));
> +    if (rc < 0) {
> +        fprintf(stderr, "couldn't set /memory/reg\n");
> +    }
> +
> +    rc = qemu_devtree_setprop_string(fdt, "/chosen", "bootargs",
> +                                      binfo->kernel_cmdline);
> +    if (rc < 0) {
> +        fprintf(stderr, "couldn't set /chosen/bootargs\n");
> +    }
> +
> +    if (binfo->initrd_size) {
> +        rc = qemu_devtree_setprop_cell(fdt, "/chosen", "linux,initrd-start",
> +                binfo->loader_start + INITRD_LOAD_ADDR);
> +        if (rc < 0) {
> +            fprintf(stderr, "couldn't set /chosen/linux,initrd-start\n");
> +        }
> +
> +        rc = qemu_devtree_setprop_cell(fdt, "/chosen", "linux,initrd-end",
> +                    binfo->loader_start + INITRD_LOAD_ADDR +
> +                    binfo->initrd_size);
> +        if (rc < 0) {
> +            fprintf(stderr, "couldn't set /chosen/linux,initrd-end\n");
> +        }
> +    }
> +
> +    cpu_physical_memory_write(addr, fdt, size);
> +
> +    return 0;
> +
> +#else
> +    fprintf(stderr, "Device tree requested, "
> +                "but qemu was compiled without fdt support\n");
> +    return -1;
> +#endif
> +}
> +
>  static void do_cpu_reset(void *opaque)
>  {
>     CPUState *env = opaque;
> @@ -221,12 +285,14 @@ static void do_cpu_reset(void *opaque)
>         } else {
>             if (env == first_cpu) {
>                 env->regs[15] = info->loader_start;
> -                if (old_param) {
> -                    set_kernel_args_old(info, info->initrd_size,
> +                if (!info->dtb_filename) {
> +                    if (old_param) {
> +                        set_kernel_args_old(info, info->initrd_size,
> +                                            info->loader_start);
> +                    } else {
> +                        set_kernel_args(info, info->initrd_size,
>                                         info->loader_start);
> -                } else {
> -                    set_kernel_args(info, info->initrd_size,
> -                                    info->loader_start);
> +                    }
>                 }
>             } else {
>                 info->secondary_cpu_reset_hook(env, info);
> @@ -251,6 +317,9 @@ void arm_load_kernel(CPUState *env, struct arm_boot_info 
> *info)
>         exit(1);
>     }
>
> +    info->dtb_filename = 
> qemu_opt_get(qemu_opts_find(qemu_find_opts("machine"),
> +                                                     0), "dtb");
> +
>     if (!info->secondary_cpu_reset_hook) {
>         info->secondary_cpu_reset_hook = default_reset_secondary;
>     }
> @@ -302,7 +371,22 @@ void arm_load_kernel(CPUState *env, struct arm_boot_info 
> *info)
>             initrd_size = 0;
>         }
>         bootloader[4] = info->board_id;
> -        bootloader[5] = info->loader_start + KERNEL_ARGS_ADDR;
> +
> +        /* for device tree boot, we pass the DTB directly in r2. Otherwise
> +         * we point to the kernel args.
> +         */
> +        if (info->dtb_filename) {
> +            /* Place the DTB after the initrd in memory */
> +            target_phys_addr_t dtb_start = 
> TARGET_PAGE_ALIGN(info->loader_start
> +                                                             + 
> INITRD_LOAD_ADDR
> +                                                             + initrd_size);
> +            if (load_dtb(dtb_start, info)) {
> +                exit(1);
> +            }
> +            bootloader[5] = dtb_start;
> +        } else {
> +            bootloader[5] = info->loader_start + KERNEL_ARGS_ADDR;
> +        }
>         bootloader[6] = entry;
>         for (n = 0; n < sizeof(bootloader) / 4; n++) {
>             bootloader[n] = tswap32(bootloader[n]);
> diff --git a/qemu-config.c b/qemu-config.c
> index 07480a4..151a61a 100644
> --- a/qemu-config.c
> +++ b/qemu-config.c
> @@ -548,6 +548,10 @@ static QemuOptsList qemu_machine_opts = {
>             .name = "append",
>             .type = QEMU_OPT_STRING,
>             .help = "Linux kernel command line",
> +        }, {
> +            .name = "dtb",
> +            .type = QEMU_OPT_STRING,
> +            .help = "Linux kernel device tree file",
>         },
>         { /* End of list */ }
>     },
> diff --git a/qemu-options.hx b/qemu-options.hx
> index 19906e5..80316ed 100644
> --- a/qemu-options.hx
> +++ b/qemu-options.hx
> @@ -2011,6 +2011,15 @@ Use @var{file1} and @var{file2} as modules and pass 
> arg=foo as parameter to the
>  first module.
>  ETEXI
>
> +DEF("dtb", HAS_ARG, QEMU_OPTION_dtb, \
> +    "-dtb    file    use 'file' as device tree image\n", QEMU_ARCH_ARM)
> +STEXI
> address@hidden -dtb @var{file}
> address@hidden -dtb
> +Use @var{file} as a device tree binary (dtb) image and pass it to the kernel
> +on boot.
> +ETEXI
> +
>  STEXI
> address@hidden table
>  ETEXI
> diff --git a/vl.c b/vl.c
> index b8bb955..03c17d6 100644
> --- a/vl.c
> +++ b/vl.c
> @@ -2453,6 +2453,9 @@ int main(int argc, char **argv, char **envp)
>             case QEMU_OPTION_append:
>                 qemu_opts_set(qemu_find_opts("machine"), 0, "append", optarg);
>                 break;
> +            case QEMU_OPTION_dtb:
> +                qemu_opts_set(qemu_find_opts("machine"), 0, "dtb", optarg);
> +                break;
>             case QEMU_OPTION_cdrom:
>                 drive_add(IF_DEFAULT, 2, optarg, CDROM_OPTS);
>                 break;
> @@ -3261,6 +3264,12 @@ int main(int argc, char **argv, char **envp)
>         exit(1);
>     }
>
> +    if (!linux_boot
> +        && qemu_opt_get(qemu_opts_find(qemu_find_opts("machine"), 0), 
> "dtb")) {
> +        fprintf(stderr, "-dtb only allowed with -kernel option\n");
> +        exit(1);
> +    }
> +
>     os_set_line_buffering();
>
>     if (init_timer_alarm() < 0) {
> --
> 1.7.5.4
>
>