On Fri, May 15, 2020 at 01:47:48PM +0300, Serge Semin wrote: > It isn't good to have numeric literals in the code especially if there > are multiple of them and they are related. Moreover in current > implementation the Tx DMA transfer activation level isn't optimal, > since it's hardwired to be at 16-32 bytes level, while it's better > to keep the SPI FIFO buffer as full as possible until all available > data is submitted. So lets introduce the DMA burst level > parametrization macros with optimal values - issue Rx transfer if at > least 16 bytes are available in the buffer and execute Tx transaction > if at least 16 bytes room is opened in SPI Tx FIFO. > - dw_writel(dws, DW_SPI_DMARDLR, 0xf); > - dw_writel(dws, DW_SPI_DMATDLR, 0x10); > + dw_writel(dws, DW_SPI_DMARDLR, RX_BURST_LEVEL - 1); > + dw_writel(dws, DW_SPI_DMATDLR, dws->fifo_len - TX_BURST_LEVEL); ...and if FIFO length is less than TX_BURST_LEVEL? For the patch that introduces definitions, i.e. keeping the last line here as dw_writel(dws, DW_SPI_DMATDLR, TX_BURST_LEVEL); I'm good. You may put your tag in that case. For fifo_len case we need to discuss in separate patch, perhaps. -- With Best Regards, Andy Shevchenko
