qemu-devel
[Top][All Lists]
Advanced

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Qemu-devel] [qemu PATCH 2/2] arm: add fw_cfg to "virt" board


From: Andrew Jones
Subject: Re: [Qemu-devel] [qemu PATCH 2/2] arm: add fw_cfg to "virt" board
Date: Fri, 28 Nov 2014 11:38:48 +0100
User-agent: Mutt/1.5.23 (2014-03-12)

On Fri, Nov 28, 2014 at 12:18:27AM +0100, Laszlo Ersek wrote:
> fw_cfg already supports exposure over MMIO (used in ppc/mac_newworld.c,
> ppc/mac_oldworld.c, sparc/sun4m.c); we can easily add it to the "virt"
> board.
> 
> The mmio register block of fw_cfg is advertized in the device tree. As
> base address we pick 0x09020000, which conforms to the comment preceding
> "a15memmap": it falls in the miscellaneous device I/O range 128MB..256MB,
> and it is aligned at 64KB.
> 
> fw_cfg automatically exports a number of files to the guest; for example,
> "bootorder" (see fw_cfg_machine_reset()).
> 
> Signed-off-by: Laszlo Ersek <address@hidden>
> ---
>  hw/arm/virt.c | 21 +++++++++++++++++++++
>  1 file changed, 21 insertions(+)
> 
> diff --git a/hw/arm/virt.c b/hw/arm/virt.c
> index 314e55b..070bd34 100644
> --- a/hw/arm/virt.c
> +++ b/hw/arm/virt.c
> @@ -68,6 +68,7 @@ enum {
>      VIRT_UART,
>      VIRT_MMIO,
>      VIRT_RTC,
> +    VIRT_FW_CFG,
>  };
>  
>  typedef struct MemMapEntry {
> @@ -107,6 +108,7 @@ static const MemMapEntry a15memmap[] = {
>      [VIRT_GIC_CPU] =    { 0x08010000, 0x00010000 },
>      [VIRT_UART] =       { 0x09000000, 0x00001000 },
>      [VIRT_RTC] =        { 0x09010000, 0x00001000 },
> +    [VIRT_FW_CFG] =     { 0x09020000, FW_CFG_SIZE + FW_CFG_DATA_SIZE },
>      [VIRT_MMIO] =       { 0x0a000000, 0x00000200 },
>      /* ...repeating for a total of NUM_VIRTIO_TRANSPORTS, each of that size 
> */
>      /* 0x10000000 .. 0x40000000 reserved for PCI */
> @@ -519,6 +521,23 @@ static void create_flash(const VirtBoardInfo *vbi)
>      g_free(nodename);
>  }
>  
> +static void create_fw_cfg(const VirtBoardInfo *vbi)
> +{
> +    hwaddr base = vbi->memmap[VIRT_FW_CFG].base;
> +    char *nodename;
> +
> +    fw_cfg_init(0, 0, base, base + FW_CFG_SIZE);
> +
> +    nodename = g_strdup_printf("/address@hidden" PRIx64, base);
> +    qemu_fdt_add_subnode(vbi->fdt, nodename);
> +    qemu_fdt_setprop_string(vbi->fdt, nodename,
> +                            "compatible", "fw-cfg,mmio");
> +    qemu_fdt_setprop_sized_cells(vbi->fdt, nodename, "reg",
> +                                 2, base, 2, FW_CFG_SIZE,
> +                                 2, base + FW_CFG_SIZE, 2, FW_CFG_DATA_SIZE);

Overkill suggestion alert, but how about defining something like

#define FW_CFG_SIZE_ALIGNED \
    MIN(QEMU_ALIGN_UP(FW_CFG_SIZE, FW_CFG_DATA_SIZE), \
        QEMU_ALIGN_UP(FW_CFG_SIZE, 4))

and then using that in your memmap size calculation and fw-cfg-data base
address calculation. The only reason I suggest this is because it's hard
to tell that fw-cfg-data's address will be naturally aligned without
hunting down the definition of FW_CFG_DATA_SIZE. And, if it were to change
(which it probably never will), then it may not be.

> +    g_free(nodename);
> +}
> +
>  static void *machvirt_dtb(const struct arm_boot_info *binfo, int *fdt_size)
>  {
>      const VirtBoardInfo *board = (const VirtBoardInfo *)binfo;
> @@ -604,6 +623,8 @@ static void machvirt_init(MachineState *machine)
>       */
>      create_virtio_devices(vbi, pic);
>  
> +    create_fw_cfg(vbi);
> +
>      vbi->bootinfo.ram_size = machine->ram_size;
>      vbi->bootinfo.kernel_filename = machine->kernel_filename;
>      vbi->bootinfo.kernel_cmdline = machine->kernel_cmdline;
> -- 
> 1.8.3.1
> 



reply via email to

[Prev in Thread] Current Thread [Next in Thread]