From: Paul Brook <paul@codesourcery.com>
To: "Peter A. G. Crosthwaite" <peter.crosthwaite@petalogix.com>
Cc: stefanha@gmail.com, edgar.iglesias@gmail.com,
qemu-devel@nongnu.org, john.williams@petalogix.com,
peter.maydell@linaro.org
Subject: Re: [Qemu-devel] [PATCH V4 0/5] Ehnahced SSI bus support + M25P80 SPI flash + Xilinx SPI controller
Date: Tue, 5 Jun 2012 02:34:08 +0100 [thread overview]
Message-ID: <201206050234.09903.paul@codesourcery.com> (raw)
In-Reply-To: <cover.1338796049.git.peter.crosthwaite@petalogix.com>
> Patch 1 Enhances SSI bus support to properly support multiple attached
> devices. An api is provided for SSI/SPI masters to select a particular
> device attached to the bus.
>
> Patch 2 is a device model for the m25p80 style SPI flash chip.
>
> Patch 3 is the Xilinx XPS SPI contoller. Its a sysbus device that
> instantiates a ssi bus, and interfaces the two (as per the controllers
> functionality)
>
> Patch 4 instantiates the XPS SPI controller in the petalogix ML605
> reference platform and connects two m25p80s to it.
>
> Patch 5 updates the stellaris machine model to use the multi slave SSI
> support
I'm still not convinced modelling this as a multipoint bus is a good idea. If
nothing else you've failed to model the case where multiple slaves are
selected simultanously. Given the chip selects are actual wires, not part of
the bus itself, I think multiple point-point busses are a better fit.
For the stellaris device we still have the synthetic mux device and
intermediate bus.
Paul
next prev parent reply other threads:[~2012-06-05 1:34 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-06-04 8:08 [Qemu-devel] [PATCH V4 0/5] Ehnahced SSI bus support + M25P80 SPI flash + Xilinx SPI controller Peter A. G. Crosthwaite
2012-06-04 8:08 ` [Qemu-devel] [PATCH V4 1/5] SSI: Built in multiple device support Peter A. G. Crosthwaite
2012-06-04 8:08 ` [Qemu-devel] [PATCH V4 2/5] m25p80: initial verion Peter A. G. Crosthwaite
2012-06-04 8:08 ` [Qemu-devel] [PATCH V4 3/5] xilinx_spi: initial version Peter A. G. Crosthwaite
2012-06-04 8:08 ` [Qemu-devel] [PATCH V4 4/5] petalogix-ml605: added spi controller with m25p80 Peter A. G. Crosthwaite
2012-06-04 8:08 ` [Qemu-devel] [PATCH V4 5/5] stellaris: Updated spi bus implementation Peter A. G. Crosthwaite
2012-06-04 8:14 ` Peter Crosthwaite
2012-06-05 1:34 ` Paul Brook [this message]
2012-06-05 1:54 ` [Qemu-devel] [PATCH V4 0/5] Ehnahced SSI bus support + M25P80 SPI flash + Xilinx SPI controller Peter Crosthwaite
2012-06-06 13:37 ` Paul Brook
2012-06-05 2:51 ` John Williams
2012-06-06 13:18 ` Paul Brook
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