On Fri, May 08, 2020 at 04:29:32PM +0300, Serge Semin wrote:
> Since DMA transfers are performed asynchronously with actual SPI
> transaction, then even if DMA transfers are finished it doesn't mean
> all data is actually pushed to the SPI bus. Some data might still be
This looks like a bug fix so it should really have gone at the start of
the series so it can be sent to Linus as a bug fix rather than waiting
for the merge window. This makes sense to me, a couple of nits below:
> +static void dw_spi_dma_wait_tx_done(struct dw_spi *dws)
> +{
> + int retry = WAIT_RETRIES;
> + unsigned long ns;
> +
> + ns = (NSEC_PER_SEC / spi_get_clk(dws)) * dws->n_bytes * BITS_PER_BYTE;
> + ns *= dw_readl(dws, DW_SPI_TXFLR);
> +
> + while (dw_spi_dma_tx_busy(dws) && retry--)
> + ndelay(ns);
How deep can the FIFO be with this IP - could we end up ndelay()ing for
non-trivial amounts of time?
> +static inline u32 spi_get_clk(struct dw_spi *dws)
> +{
> + u32 div = dw_readl(dws, DW_SPI_BAUDR);
> +
> + return div ? dws->max_freq / div : 0;
Please write normal conditional statements rather than using the ternery
operator - it helps with legibility.
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