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Re: [Qemu-devel] [PATCH] ide: Enable byte&word access to DMA address reg
From: |
Aurelien Jarno |
Subject: |
Re: [Qemu-devel] [PATCH] ide: Enable byte&word access to DMA address register |
Date: |
Mon, 5 May 2008 23:20:04 +0200 |
User-agent: |
Mutt/1.5.17+20080114 (2008-01-14) |
On Mon, May 05, 2008 at 10:20:39AM +0200, Jan Kiszka wrote:
> According to the specs, also byte- and word-wise access to the busmaster
> DMA address register is allowed. Patch below fixes the IDE emulation
> in this regard (avoiding to touch the existing common case of 32-bit
> access) and makes our guest happy.
>
> Signed-off-by: Jan Kiszka <address@hidden>
> ---
> hw/ide.c | 25 +++++++++++++++++++++++++
> 1 file changed, 25 insertions(+)
>
> Index: b/hw/ide.c
> ===================================================================
> --- a/hw/ide.c
> +++ b/hw/ide.c
> @@ -2838,6 +2838,29 @@ static void bmdma_writeb(void *opaque, u
> }
> }
>
> +static uint32_t bmdma_addr_readb(void *opaque, uint32_t addr)
> +{
> + BMDMAState *bm = opaque;
> + uint32_t val;
> + val = (bm->addr >> ((addr & 3) * 8)) & 0xff;
> +#ifdef DEBUG_IDE
> + printf("%s: 0x%08x\n", __func__, val);
> +#endif
> + return val;
> +}
> +
> +static void bmdma_addr_writeb(void *opaque, uint32_t addr, uint32_t val)
> +{
> + BMDMAState *bm = opaque;
> + int shift = (addr & 3) * 8;
> +#ifdef DEBUG_IDE
> + printf("%s: 0x%08x\n", __func__, val);
> +#endif
> + bm->addr &= ~(0xFF << shift);
> + bm->addr |= (val & 0xfc) << shift;
Are you sure it is correct? If you want to make sure the 2 lowest bits
are 0, it should be instead:
bm->addr |= ((val & 0xFF) << shift) & ~3;
> + bm->cur_addr = bm->addr;
> +}
> +
> static uint32_t bmdma_addr_readl(void *opaque, uint32_t addr)
> {
> BMDMAState *bm = opaque;
> @@ -2876,6 +2899,8 @@ static void bmdma_map(PCIDevice *pci_dev
> register_ioport_write(addr + 1, 3, 1, bmdma_writeb, bm);
> register_ioport_read(addr, 4, 1, bmdma_readb, bm);
>
> + register_ioport_write(addr + 4, 4, 1, bmdma_addr_writeb, bm);
> + register_ioport_read(addr + 4, 4, 1, bmdma_addr_readb, bm);
> register_ioport_write(addr + 4, 4, 4, bmdma_addr_writel, bm);
> register_ioport_read(addr + 4, 4, 4, bmdma_addr_readl, bm);
> addr += 8;
>
Otherwise, looks ok. Are word accesses supported? If yes it may be nice
to implement bmdma_addr_writew and bmdma_addr_readw at the same time.
--
.''`. Aurelien Jarno | GPG: 1024D/F1BCDB73
: :' : Debian developer | Electrical Engineer
`. `' address@hidden | address@hidden
`- people.debian.org/~aurel32 | www.aurel32.net