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<concept id="GUID-9BBDFF77-5E2C-4E13-BEB3-716CC80B3375" xml:lang="en"><title>SDIO Implementation

Overview</title><shortdesc>How to port the SDIO Controller for your platform to provide the

SDIO adaptation.</shortdesc><prolog><metadata><keywords/></metadata></prolog><conbody>

<p>The SDIO implementation shares most of its functionality with the Secure

Digital (SD) Controller, which in turn extends the MultiMedia Card (MMC) Controller.

SDIO adds support for data transfer between Input/Output hardware included

on SDIO cards. The SD stack is used to access memory functions on SDIO combined

(or combo) cards. The SDIO Controller recognizes SDIO cards, extends the set

of available commands, and provides an API so that other drivers can access

the card.</p>

<p>Providing an SDIO adaptation for your platform means porting the SDIO Controller.

This is done by implementing the SDIO functions of the Platform-Specific Layer

(PSL).</p>

<section id="GUID-64516BCF-2245-46DF-9E7F-FFC18AC7F691"><title>Prerequisites</title><p>SDIO

depends on SD and MMC: the SDIO protocol is a super-set of the SD protocol

(and of the MMC protocol). Therefore, in addition to the SDIO standard, you

need to know about the following:<ul>

<li><p>SD (Secure Digital)</p></li>

<li><p>MMC (MultiMedia Card)</p></li>

</ul></p><p>Moreover, you must have ported the underlying SD Controller to

your platform before doing so for SDIO. See the following porting guides:<ul>

<li><p><xref href="GUID-E194A923-99E7-5DC1-BB78-D050A4793A60.dita">SD Controller

PSL Implementation</xref></p></li>

<li><p><xref href="GUID-86082C0C-B0EE-5E7C-85B4-4A509066012F.dita">MMC Porting

Implementation Tutorial</xref></p></li>

</ul></p>     </section>

<section id="GUID-A6598353-0AC5-4DB0-82AD-C2F397CB5CD0"><title>Architecture</title><p>The

following diagram illustrates the implementation of the SDIO extension for

the MMC Controller. The classes in green provide the hardware interface and

the classes in blue implement the platform-specific functions.</p><fig id="GUID-AA66D99B-9EF2-4803-8D43-A3BDA180C9C9">

<title>SDIO Controller classes</title>

<image href="GUID-D5030CC5-1FC1-40F3-9D68-4A454B25C58B_d0e322087_href.png" placement="inline"/>

</fig></section>

<section id="GUID-20DF01A9-64AF-45E6-8F22-2E384F4177EA"><title>Implementation</title>The

Platform-Independent Layer (PIL) of the SDIO Controller is made up from three

sets of files described in the following table:<p><table id="GUID-54A82958-4168-42CD-81DE-466CEA0FEEFC">

<tgroup cols="2"><colspec colname="col1"/><colspec colname="col2"/>

<thead>

<row>

<entry valign="top">Standard</entry>

<entry valign="top">Source code location</entry>

</row>

</thead>

<tbody>

<row>

<entry>MMC</entry>

<entry><p><filepath>os/kernelhwsrv/kernel/eka/drivers/pbus/mmc</filepath></p><p>See

also <xref href="GUID-40F2BC43-5022-5F4E-B445-56FEF43FEB8B.dita">Code Organisation</xref> in

the MMC section.</p></entry>

</row>

<row>

<entry>SD</entry>

<entry><filepath>os/kernelhwsrv/kernel/eka/drivers/pbus/mmc/sdcard/sdcard3c/</filepath><p>Also

see <xref href="GUID-E194A923-99E7-5DC1-BB78-D050A4793A60.dita#GUID-E194A923-99E7-5DC1-BB78-D050A4793A60/GUID-59DA32AA-97F3-4001-9B6F-887E986C633D">Source

Code</xref> in the SD section.</p></entry>

</row>

<row>

<entry>SDIO</entry>

<entry><filepath>os/kernelhwsrv/kernel/eka/drivers/pbus/mmc/sdcard/sdcard3c/sdio/</filepath></entry>

</row>

</tbody>

</tgroup>

</table></p><p>The Platform-Specific Layer (PSL) should be located in a variant

directory and have a similar folder hierarchy to the PIL. It should provide

the following implementations:<ul>

<li><p>Stack</p></li>

<li><p>Power Supply Unit (PSU)</p></li>

</ul> </p></section>

</conbody></concept>