CAM, FreeBSD, GSoC, mmccam, RTEMS, SDIO

Backporting MMCCAM/SDIO framework to FreeBSD head 642b174dadd

My phase 2, GSoC objectives includes Backporting the current(rev: d6756a3ac8 ) MMCCAM framework to FreeBSD head 642b174dadd and then importing it to RTEMS. This post mainly concerns with intricacies and workarounds during the backporting process. Backporting is a process that enables old kernels run a latest driver. MMCCAM framework is one such enhancement in the past few months that enables FreeBSD to talk to devices behind the SDIO bus. It’s a major architectural change, that enables further…

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CAM, FreeBSD, mmccam, SDIO, Software

Implementing a MMC/SD/SDIO stack using CAM framework(Part 2)

Hi, In the next part lets look at other files which makes up the SDIO stack within mmccam framework. Please have  a look at previous part for more info: http://uditagarwal.in/index.php/2018/03/19/implementing-a-mmc-sd-sdio-stack-using-cam-framework/ mmc_sdio.c

sdio_fill_mmcio_rw_direct is basically a wrapper for CMD_52 that’s needed to read/write directly into mmc register R5. Remember that register R5 in mmc, is used for RCA(Relative card address) management. It’s right time now to talk about different command types of SD/MMC/SDIO: broadcast commands (bc), no…

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Hardware

Understanding SD, SDIO and MMC Interface

    In this blog post i will present the gist of the paper http://www.kaltech.co.il/pdf/Eureka_sd_wp1.pdf ,¬† It’s crucial for anyone willing to understand how removable devices like sd card work, different protocols/functionalities they support. Secure Digital (SD) memory card today, is one of the most popular non-volatile removable data storage media for consumer applications. It’s not intended to remove hard-disk. Hard-disk can still deliver much better speed and memory capacity. SD card is used in applications demanding…

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