[Qemu-devel] Re: [PATCH] sparc32 protect read-only bits in DMA CSR registers

[Blue Swirl]

Thanks, applied. You forgot SoB-line, I copied it from the previous version.

On Sat, May 22, 2010 at 8:38 AM, Artyom Tarasenko
<address@hidden> wrote:
> On a real hardware changing read-only bits has no effect
> Use a mask common for SCSI and Ethernet registers. The crucial
> bit is DMA_INTR, because setting or clearing it may produce
> spurious interrupts.
>
> This patch allows booting Solaris 2.3
> ---
>  hw/sparc32_dma.c |   12 ++++++++----
>  1 files changed, 8 insertions(+), 4 deletions(-)
>
> diff --git a/hw/sparc32_dma.c b/hw/sparc32_dma.c
> index 3ceb851..b521707 100644
> --- a/hw/sparc32_dma.c
> +++ b/hw/sparc32_dma.c
> @@ -62,6 +62,9 @@
>  #define DMA_DRAIN_FIFO 0x40
>  #define DMA_RESET 0x80
>
> +/* XXX SCSI and ethernet should have different read-only bit masks */
> +#define DMA_CSR_RO_MASK 0xfe000007
> +
>  typedef struct DMAState DMAState;
>
>  struct DMAState {
> @@ -187,7 +190,7 @@ static void dma_mem_writel(void *opaque, 
> target_phys_addr_t addr, uint32_t val)
>     switch (saddr) {
>     case 0:
>         if (val & DMA_INTREN) {
> -            if (val & DMA_INTR) {
> +            if (s->dmaregs[0] & DMA_INTR) {
>                 DPRINTF("Raise IRQ\n");
>                 qemu_irq_raise(s->irq);
>             }
> @@ -204,16 +207,17 @@ static void dma_mem_writel(void *opaque, 
> target_phys_addr_t addr, uint32_t val)
>             val &= ~DMA_DRAIN_FIFO;
>         } else if (val == 0)
>             val = DMA_DRAIN_FIFO;
> -        val &= 0x0fffffff;
> +        val &= ~DMA_CSR_RO_MASK;
>         val |= DMA_VER;
> +        s->dmaregs[0] = (s->dmaregs[0] & DMA_CSR_RO_MASK) | val;
>         break;
>     case 1:
>         s->dmaregs[0] |= DMA_LOADED;
> -        break;
> +        /* fall through */
>     default:
> +        s->dmaregs[saddr] = val;
>         break;
>     }
> -    s->dmaregs[saddr] = val;
>  }
>
>  static CPUReadMemoryFunc * const dma_mem_read[3] = {
> --
> 1.6.2.5
>
>