The SPI controller's documentation (I only had access to the RK3399, RK3368 and PX30 TRMs) specifies that, when operating in master-mode, the controller will stop the SCLK to avoid RXFIFO overruns and TXFIFO underruns. Looks like my worries that we'd need to support DMA-330 (aka PL330) to make any further progress were unfounded.
This adds a driver-data structure to capture hardware-specific settings of individual controller instances (after all, we don't know if all versions are well-behaved) and adds a 'master_manages_fifo' flag to it. The first use of said flag is in the optimised receive-only transfer-handler, which can now request 64Kframe (i.e. 128KByte) bursts of data on each reprogramming of CTRLR1 (i.e. every time through the loop).
This improves throughput to 46.85MBit/s (a 94.65% bus-utilisation).
Signed-off-by: Philipp Tomsich philipp.tomsich@theobroma-systems.com
drivers/spi/rk_spi.c | 24 ++++++++++++++++++++++-- 1 file changed, 22 insertions(+), 2 deletions(-)
Applied to u-boot-rockchip, thanks!