On Mon, Feb 19, 2018 at 11:47:23AM +0000, Meghana Madhyastha wrote:
> -Remove chunk splitting in tinydrm_spi_transfer in tinydrm-helpers as The spi core will split a buffer into max_dma_len chunks for the
> spi controller driver to handle.
> -Remove automatic byte swapping in tinydrm_spi_transfer as it doesn't have users.
> -Remove the upper bound check on dma transfer length in bcm2835_spi_can_dma().
This looks like a series of related changes that should be split up into
individual commits, probably at least one per bullet point there.
> - /* BCM2835_SPI_DLEN has defined a max transfer size as
> - * 16 bit, so max is 65535
> - * we can revisit this by using an alternative transfer
> - * method - ideally this would get done without any more
> - * interaction...
> - */
> - if (tfr->len > 65535) {
> - dev_warn_once(&spi->dev,
> - "transfer size of %d too big for dma-transfer\n",
> - tfr->len);
> - return false;
> - }
> -
The changelog says we're removing this check but doesn't explain why
and...
> /* if we run rx/tx_buf with word aligned addresses then we are OK */
> if ((((size_t)tfr->rx_buf & 3) == 0) &&
> (((size_t)tfr->tx_buf & 3) == 0))
> @@ -461,7 +448,7 @@ static void bcm2835_dma_init(struct spi_master *master, struct device *dev)
>
> /* all went well, so set can_dma */
> master->can_dma = bcm2835_spi_can_dma;
> - master->max_dma_len = 65535; /* limitation by BCM2835_SPI_DLEN */
> + master->max_dma_len = 65528; /* limitation by BCM2835_SPI_DLEN */
> /* need to do TX AND RX DMA, so we need dummy buffers */
> master->flags = SPI_MASTER_MUST_RX | SPI_MASTER_MUST_TX;
...this bit of the change isn't mentioned at all?
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