check alignment for DMA buffers #17
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no need to check it this way.. if you just delete the lower bits the program will crash too because it will overwrite other variables. |
but |
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Yes, It does writes wrong data, if you move the buffer... and the user does not know about it. So where is this better? |
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its even worse. |
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Yes, that's why it just checks the alignment and returns -1 to inform the user, if the alignment is wrong. Or do I miss anything here? |
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oops, forgot about the return.. you're right. forget it. |
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I really like the idea of using DMA to access the SD card, but you should check the user-supplied buffers to
SDHC_CardReadBlock(()andSDHC_CardWriteBlock()for a correct alignment to prevent data corruption. The least 2 significant bits ofSDHC_DSADDRare always 0 on a K66 device, therefore the buffer address has to be 4 byte aligned.