Re: [PATCH v2 1/2] spi: Split spi message into chunks of <65535 in the spi subsystem

Hi Meghana,

On Sat, Mar 10, 2018 at 4:51 PM, Meghana Madhyastha meghana.madhyastha@gmail.com wrote:

Split spi messages into chunks of <65535 in the spi subsystem and remove the message length warning in bcm2835_spi_can_dma. This is so that the messages can be transferred via dma and that the tinydrm drivers need not split it.

Signed-off-by: Meghana Madhyastha meghana.madhyastha@gmail.com

Thanks for your patch!

--- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -1242,6 +1242,14 @@ static void __spi_pump_messages(struct spi_controller *ctlr, bool in_kthread) trace_spi_message_start(ctlr->cur_msg);

    if (ctlr->prepare_message) {

•           gfp_t gfp_flags = GFP_KERNEL | GFP_DMA;
  

•           size_t max_transfer_size = 32000;
  

Do you really want to impose this arbitrary limit (which BTW doesn't match the value in the patch description) to each and every SPI controller driver?

•           ret = spi_split_transfers_maxsize(ctlr, ctlr->cur_msg, max_transfer_size, gfp_flags);
  

•           if (ret) {
  

•                   dev_err(&ctlr->dev,
  

•                           "failed to split message\n");
  

•                   goto out;
  

•           }
            ret = ctlr->prepare_message(ctlr, ctlr->cur_msg);
            if (ret) {
                    dev_err(&ctlr->dev, "failed to prepare message: %d\n",
  

Gr{oetje,eeting}s,

Geert

-- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds