drivers: usdhc: don't invalidate cache on non-blocking non-DMA transfer#25
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tchebb wants to merge 1 commit intonxp-mcuxpresso:mainfrom
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drivers: usdhc: don't invalidate cache on non-blocking non-DMA transfer#25tchebb wants to merge 1 commit intonxp-mcuxpresso:mainfrom
tchebb wants to merge 1 commit intonxp-mcuxpresso:mainfrom
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In USDHC_TransferNonBlocking(), DMA may be disabled if the user passes a NULL dmaConfig or if USDHC_SetAdmaTableConfig() fails. In that case, USDHC_TransferNonBlocking() correctly skips its cache clean, but USDHC_TransferHandleData() doesn't skip its cache invalidate, meaning it replaces the entire data buffer's cache line with stale data from RAM. This memory corruption causes undefined behavior and system instability. Fix the issue by remembering if we used DMA and only invalidating the cache if we did. This matches the behavior of USDHC_TransferBlocking(). Also fix USDHC_TransferScatterGatherADMANonBlocking(). Memory corruption may still occur if the DMA buffer shares a cache line with unrelated data that the CPU updates during a transfer, but there is no way for us to detect that in the SDK. The user should avoid that situation. Fixes nxp-mcuxpresso#20
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@tchebb Thanks a lot for the fix-up. |
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In
USDHC_TransferNonBlocking(), DMA may be disabled if the user passes a NULLdmaConfigor ifUSDHC_SetAdmaTableConfig()fails. In that case,USDHC_TransferNonBlocking()correctly skips its cache clean, butUSDHC_TransferHandleData()doesn't skip its cache invalidate, meaning it replaces the entire data buffer's cache line with stale data from RAM. This memory corruption causes undefined behavior and system instability.Fix the issue by remembering if we used DMA and only invalidating the cache if we did. This matches the behavior of
USDHC_TransferBlocking(). Also fixUSDHC_TransferScatterGatherADMANonBlocking().Memory corruption may still occur if the DMA buffer shares a cache line with unrelated data that the CPU updates during a transfer, but there is no way for us to detect that in the SDK. The user should avoid that situation.
Fixes #20