Imx6QP：emmc boot with DMA in uboot

[zhuchaozhu]

Dear my friends

      
     I would like to modify the uboot emmc driver so that it supports dma boot ，because i think it takes a lot of time to load the kernel and ramdisk image
     In fact, my real goal is to save boot time, I have cut off a lot of useless drivers, but still need about 480ms time. So I hope uboot starting from emmc using DMA. At the same time I need to know if it can save some time
     Ihope someone can give me some help or some of the views, I can do to achieve the goal .

     Thank you

[fabio_estevam]

Here are some general hints for booting under one second:

Booting i.MX6 under one second - i.MXDev Blog 

Also, U-Boot 2017.03 has an improvement for the copy (cp command) implementation based on assembly library.

If you use cp command in U-Boot  you may consider moving to the latest U-Boot version.

[igorpadykov · Accepted solution]

Hi zhuchao

actually i.MX6DQP uSDHC module has own dma engine, please

refer to Figure 68-1. System Connection of the uSDHC i.MX6DQP Reference Manual

http://cache.nxp.com/files/soft_dev_tools/doc/support_info/iMX6DQPRM.pdf

Best regards
igor
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