Unverified Commit 8fc13b82 authored by David Lechner's avatar David Lechner Committed by Mark Brown
Browse files

spi: axi-spi-engine: don't repeat mode config for offload 



Add an optimization to avoid repeating the config instruction in each
SPI message when using SPI offloading. Instead, the instruction is
run once when the SPI offload trigger is enabled.

This is done to allow higher sample rates for ADCs using this SPI
controller.

Signed-off-by: default avatarDavid Lechner <dlechner@baylibre.com>
Link: https://patch.msgid.link/20250428-adi-main-v1-2-4b8a1b88a212@baylibre.com


Signed-off-by: default avatarMark Brown <broonie@kernel.org>
parent 1d0ee0c9

drivers/spi/spi-axi-spi-engine.c

+30 −3
Original line number Diff line number Diff line
@@ -141,6 +141,7 @@ struct spi_engine_offload { 
	struct spi_engine *spi_engine;

	unsigned long flags;

	unsigned int offload_num;

	unsigned int spi_mode_config;

};



struct spi_engine {
@@ -284,6 +285,7 @@ static void spi_engine_compile_message(struct spi_message *msg, bool dry, 
{

	struct spi_device *spi = msg->spi;

	struct spi_controller *host = spi->controller;

	struct spi_engine_offload *priv;

	struct spi_transfer *xfer;

	int clk_div, new_clk_div, inst_ns;

	bool keep_cs = false;
@@ -297,9 +299,18 @@ static void spi_engine_compile_message(struct spi_message *msg, bool dry, 


	clk_div = 1;



	/*

	 * As an optimization, SPI offload sets once this when the offload is

	 * enabled instead of repeating the instruction in each message.

	 */

	if (msg->offload) {

		priv = msg->offload->priv;

		priv->spi_mode_config = spi_engine_get_config(spi);

	} else {

		spi_engine_program_add_cmd(p, dry,

			SPI_ENGINE_CMD_WRITE(SPI_ENGINE_CMD_REG_CONFIG,

				spi_engine_get_config(spi)));

	}



	xfer = list_first_entry(&msg->transfers, struct spi_transfer, transfer_list);

	spi_engine_gen_cs(p, dry, spi, !xfer->cs_off);
@@ -842,6 +853,22 @@ static int spi_engine_trigger_enable(struct spi_offload *offload) 
	struct spi_engine_offload *priv = offload->priv;

	struct spi_engine *spi_engine = priv->spi_engine;

	unsigned int reg;

	int ret;



	writel_relaxed(SPI_ENGINE_CMD_SYNC(0),

		spi_engine->base + SPI_ENGINE_REG_CMD_FIFO);



	writel_relaxed(SPI_ENGINE_CMD_WRITE(SPI_ENGINE_CMD_REG_CONFIG,

					    priv->spi_mode_config),

		       spi_engine->base + SPI_ENGINE_REG_CMD_FIFO);



	writel_relaxed(SPI_ENGINE_CMD_SYNC(1),

		spi_engine->base + SPI_ENGINE_REG_CMD_FIFO);



	ret = readl_relaxed_poll_timeout(spi_engine->base + SPI_ENGINE_REG_SYNC_ID,

					 reg, reg == 1, 1, 1000);

	if (ret)

		return ret;



	reg = readl_relaxed(spi_engine->base +

			    SPI_ENGINE_REG_OFFLOAD_CTRL(priv->offload_num));