> From: Bagas Sanjaya <bagasdotme@xxxxxxxxx> > Sent: Thursday, October 6, 2022 7:31 AM > > On 10/5/22 17:47, Parav Pandit wrote: > > @@ -1927,10 +1927,12 @@ There are some more advanced barrier > functions: > > before we read the data from the descriptor, and the dma_wmb() > allows > > us to guarantee the data is written to the descriptor before the device > > can see it now has ownership. The dma_mb() implies both a > dma_rmb() and > > - a dma_wmb(). Note that, when using writel(), a prior wmb() is not > needed > > - to guarantee that the cache coherent memory writes have completed > before > > - writing to the MMIO region. The cheaper writel_relaxed() does not > provide > > - this guarantee and must not be used here. > > + a dma_wmb(). Note that, when using writel(), a prior barrier is not > > + needed to guarantee that the cache coherent memory writes have > completed > > + before writing to the MMIO region. The cheaper writel_relaxed() does > not > > + provide this guarantee and must not be used here. Hence, writeX() is > always > > + preferred which inserts needed platform specific barrier before writing > to > > + the specified MMIO region. > > > > Did you mean that writeX() is write() function family? Yes.
