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Re: [Qemu-devel] [PATCH 1/3] hw/sd/pxa2xx_mmci: convert to SysBusDevice
From: |
Kevin O'Connor |
Subject: |
Re: [Qemu-devel] [PATCH 1/3] hw/sd/pxa2xx_mmci: convert to SysBusDevice object |
Date: |
Fri, 4 Dec 2015 14:24:01 -0500 |
User-agent: |
Mutt/1.5.24 (2015-08-30) |
On Fri, Dec 04, 2015 at 10:50:21AM -0800, Peter Crosthwaite wrote:
> > FWIW, I don't think the SD card will be qdevified because it doesn't
> > need a bus. It's similar indeed to SerialState, which was supposed to
> > be the poster child of QOM embedding and never got QOMified.
>
> SD is a bus in its own right and should be busified and QOMified IMO.
> SDHCI can talk to non-sd cards (SDIO). There is also a range of
> incompatible cards that you can talk to - MMC/eMMC/SD(H|S|X)C. I think
> anything that couples the controller to an SD card is a bug, the card
> and device should be arranged as separate devices.
>
> > A host controller controls exactly one SD card, the SSI bridge is also
> > for exactly one SD card, etc.
>
> I think you can RYO chip selects with a GPIO and control multiple SD
> cards with one SDHCI.
In practice, the SDHCI controllers are one-to-one with cards. This is
codified in the sdhci spec as it has a "card present" bit and "port
location" information that is per controller.
I suppose in theory, one could put an SDHCI contoller into SPI
compatibility mode and "hot wire" it into a bus, but qemu doesn't
support that anyway, and it is a lot of complexity for something that
is not done in practice.
-Kevin
- Re: [Qemu-devel] [PATCH 1/3] hw/sd/pxa2xx_mmci: convert to SysBusDevice object, Peter Maydell, 2015/12/03
- Re: [Qemu-devel] [PATCH 1/3] hw/sd/pxa2xx_mmci: convert to SysBusDevice object, Markus Armbruster, 2015/12/04
- Re: [Qemu-devel] [PATCH 1/3] hw/sd/pxa2xx_mmci: convert to SysBusDevice object, Paolo Bonzini, 2015/12/04
- Re: [Qemu-devel] [PATCH 1/3] hw/sd/pxa2xx_mmci: convert to SysBusDevice object, Peter Crosthwaite, 2015/12/04
- Re: [Qemu-devel] [PATCH 1/3] hw/sd/pxa2xx_mmci: convert to SysBusDevice object,
Kevin O'Connor <=
- Re: [Qemu-devel] [PATCH 1/3] hw/sd/pxa2xx_mmci: convert to SysBusDevice object, Peter Crosthwaite, 2015/12/06
- Re: [Qemu-devel] [PATCH 1/3] hw/sd/pxa2xx_mmci: convert to SysBusDevice object, Kevin O'Connor, 2015/12/07
- Re: [Qemu-devel] [PATCH 1/3] hw/sd/pxa2xx_mmci: convert to SysBusDevice object, Markus Armbruster, 2015/12/07
- Re: [Qemu-devel] [PATCH 1/3] hw/sd/pxa2xx_mmci: convert to SysBusDevice object, Paolo Bonzini, 2015/12/07
- Re: [Qemu-devel] [PATCH 1/3] hw/sd/pxa2xx_mmci: convert to SysBusDevice object, Markus Armbruster, 2015/12/07
- Re: [Qemu-devel] [PATCH 1/3] hw/sd/pxa2xx_mmci: convert to SysBusDevice object, Peter Maydell, 2015/12/07