Re: [PATCH 5/5] cmd646: move device-specific BMDMA registers to separate memory region

[Bernhard Beschow <shentey@gmail.com>]

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On Tue, Jun 13, 2023 at 12:39 AM Philippe Mathieu-Daudé <philmd@linaro.org>
wrote:

> On 12/6/23 21:28, Bernhard Beschow wrote:
> >
> >
> > Am 9. Juni 2023 18:51:19 UTC schrieb Mark Cave-Ayland <
> mark.cave-ayland@ilande.co.uk>:
> >> The aim here is to eliminate any device-specific registers from the
> main BMDMA
> >> bar memory region so it can potentially be moved into the shared PCI
> IDE device.
> >>
> >> For each BMDMA bus create a new cmd646-bmdma-specific memory region
> representing
> >> the device-specific BMDMA registers and then map them using aliases
> onto the
> >> existing BMDMAState memory region.
> >>
> >> Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
> >> ---
> >> hw/ide/cmd646.c         | 111 +++++++++++++++++++++++++++++++---------
> >> include/hw/ide/cmd646.h |   4 ++
> >> 2 files changed, 90 insertions(+), 25 deletions(-)
>
>
> >> struct CMD646IDEState {
> >>      PCIIDEState parent_obj;
> >> +
> >> +    MemoryRegion bmdma_mem[2];
> >> +    MemoryRegion bmdma_mem_alias[2][2];
> >
> > The added complexity of a two-dimensional alias array seems like a tough
> call for me. I'm not totally against it but I'm reluctant.
>
> Alternative:
>
>          struct {
>              MemoryRegion mem;
>              MemoryRegion mem_alias[2];
>

If `mem_alias` became an anonymous struct as well we could avoid fiddling
with two indices in a matrix, lowering the complexity.

Best regards,
Bernhard

>          } bmdma[2];
>
> >> };
> >>
> >> #endif
> >
>
>

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