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78 lines
2.4 KiB
Text
78 lines
2.4 KiB
Text
The U-Boot Driver Model Project
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===============================
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PCMCIA analysis
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===============
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Viktor Krivak <viktor.krivak@gmail.com>
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2012-03-17
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I) Overview
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-----------
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U-boot implements only 2 methods to interoperate with pcmcia. One to turn
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device on and other to turn device off. Names of these methods are usually
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pcmcia_on() and pcmcia_off() without any parameters. Some files in driver
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directory implements only internal API. These methods aren't used outside
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driver directory and they are not converted to new driver model.
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II) Approach
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-----------
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1) New API
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----------
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Current API is preserved and all internal methods are hiden.
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struct ops {
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void (*pcmcia_on)(struct instance *i);
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void (*pcmcia_off)(struct instance *i);
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}
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2) Conversion
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-------------
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In header file pcmcia.h are some other variables which are used for
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additional configuration. But all have to be moved to platform data or to
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specific driver implementation.
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3) Platform data
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----------------
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Many boards have custom implementation of internal API. Pointers to these
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methods are stored in platform_data. But the most implementations for Intel
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82365 and compatible PC Card controllers and Yenta-compatible
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PCI-to-CardBus controllers implement whole API per board. In these cases
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pcmcia_on() and pcmcia_off() behave only as wrappers and call specific
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board methods.
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III) Analysis of in-tree drivers
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--------------------------------
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1) i82365.c
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-----------
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Driver methods have different name i82365_init() and i82365_exit but
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all functionality is the same. Board files board/atc/ti113x.c and
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board/cpc45/pd67290.c use their own implementation of these method.
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In this case all methods in driver behave only as wrappers.
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2) marubun_pcmcia.c
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-------------------
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Meets standard API behaviour. Simple conversion.
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3) mpc8xx_pcmcia.c
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------------------
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Meets standard API behaviour. Simple conversion.
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4) rpx_pcmcia.c
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---------------
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Implements only internal API used in other drivers. Non of methods
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implemented here are used outside driver model.
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5) ti_pci1410a.c
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----------------
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Has different API but methods in this file are never called. Probably
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dead code.
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6)tqm8xx_pcmcia.c
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-----------------
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Implements only internal API used in other drivers. Non of methods
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implemented here are used outside driver model.
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