Re: [Qemu-devel] [Qemu-ppc] [PATCH 07/10] PPC: guts: Add emulation of a few more registers

[Scott Wood <scottwood@freescale.com>]

On Mon, 2014-01-20 at 00:44 +0100, Alexander Graf wrote:
> The GUTS device is used by system software to find out about hardware
> details of the current system.
> 
> We only emulate the bare minimum to be able to reboot a guest which is
> not sufficient to make u-boot happy.
> 
> Add a few more registers to our portfolio with dummy values.
> 
> Signed-off-by: Alexander Graf <agraf@suse.de>
> ---
>  hw/ppc/mpc8544_guts.c | 12 ++++++++++++
>  1 file changed, 12 insertions(+)
> 
> diff --git a/hw/ppc/mpc8544_guts.c b/hw/ppc/mpc8544_guts.c
> index a10abe9..af8c742 100644
> --- a/hw/ppc/mpc8544_guts.c
> +++ b/hw/ppc/mpc8544_guts.c
> @@ -25,6 +25,8 @@
>  #define MPC8544_GUTS_RSTCR_RESET      0x02
>  
>  #define MPC8544_GUTS_ADDR_PORPLLSR    0x00
> +#define PORPLLSR_SYS_RATIO_MAX        0x3e
> +#define PORPLLSR_CPU0_RATIO_MAX       (0x3f << 16)
>  #define MPC8544_GUTS_ADDR_PORBMSR     0x04
>  #define MPC8544_GUTS_ADDR_PORIMPSCR   0x08
>  #define MPC8544_GUTS_ADDR_PORDEVSR    0x0C
> @@ -36,6 +38,7 @@
>  #define MPC8544_GUTS_ADDR_GPINDR      0x50
>  #define MPC8544_GUTS_ADDR_PMUXCR      0x60
>  #define MPC8544_GUTS_ADDR_DEVDISR     0x70
> +#define DEVDISR_DISABLED_NONE         0x0
>  #define MPC8544_GUTS_ADDR_POWMGTCSR   0x80
>  #define MPC8544_GUTS_ADDR_MCPSUMR     0x90
>  #define MPC8544_GUTS_ADDR_RSTRSCR     0x94
> @@ -73,6 +76,15 @@ static uint64_t mpc8544_guts_read(void *opaque, hwaddr addr,
>  
>      addr &= MPC8544_GUTS_MMIO_SIZE - 1;
>      switch (addr) {
> +    case MPC8544_GUTS_ADDR_PORPLLSR:
> +        value = PORPLLSR_SYS_RATIO_MAX | PORPLLSR_CPU0_RATIO_MAX;
> +        break;
> +    case MPC8544_GUTS_ADDR_PORDEVSR:
> +        value = 0;
> +        break;
> +    case MPC8544_GUTS_ADDR_DEVDISR:
> +        value = DEVDISR_DISABLED_NONE;
> +        break;

But we don't actually have most of these devices that you're claiming
aren't disabled via DEVDISR -- and with the paravirt target, what do
these registers even mean?

I'd rather see U-Boot not touch these registers for the QEMU target,
rather than returning arbitrary values.

-Scott