061fed753e
When we send MMC commads that contain data the controller provides no description of the order of events and we need to be able to send data from and to the controller "when needed". Changed the code to react on buffer read and buffer write ready based on interrupts. Change-Id: I60c9140bf0e45b74be6475054564d4e1bd89f21e
52 lines
2.1 KiB
Plaintext
52 lines
2.1 KiB
Plaintext
This directory contains code to access MMC based devices.
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It was created during the initial port of MINIX to the ARM platform. mmbclk
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implements a normal MINIX block device. It uses the interfaces defined in
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mmchost.h to perform it's operations.
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mmchost_mmchs is the MMC host controller driver for the TI omap device range.
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It contains the logic to access SD cards on that device.
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drivers/mmc
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|-- Makefile (The makefile)
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|-- mmclog.h (A simpel logging system)
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|-- omap_mmc.h (TI Omap register definitions)
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|-- sdhcreg.h (BSD headers for the MMC layer)
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|-- sdmmcreg.h (BSD headers for the MMC layer)
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|-- mmcblk.c (MINIX 3 block device)
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|-- mmchost.h (interface between the block device and the MMC layer)
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|-- mmchost_mmchs.c (Driver to use on the ARM port/beagle)
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'-- README.txt (This file)
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Future work:
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============
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* Creating a more generic MMC layer
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The SD protocol is well defined and the imported the netbsd sdhcreg and
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sdmmcreg headers will allow us to make the MMC interface more generic. We would
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like mmchost_mmchs to be split in a generic part and a specific part.
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* 8 bits access
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The driver currently only reads data over 1 or 4 bits address lines. Adding support
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for 4 or 8 bits(for movinands) mode is very welcome.
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* DMA.
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The OMAP driver allows the usage of DMA. Adding DMA support will increase the
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performance of the driver
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* Removal of the PRIVCTL call.
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The MMC driver uses memory mapped IO to perform it's operations. On i386 it is
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the pci driver that will grant access to certain piece of memory to a driver.
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On the ARM port we lack pci and other self describing busses. In the current
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driver the driver will itself grant itself access to the correct piece of
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memory but this is unwanted behavior. We currently as thinking about two
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possible solutions. The first would be to add the memory ranges in system.conf.
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The second would be to modify the PCI driver to grant access to memory based on
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a fixed configuration. For example we could use the driver tree to perform
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device discovery and granting access to devices.
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* TODO removal
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The driver contains (quite a few) TODO's where the code need to be improved.
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