Unverified Commit d861b417 authored by David Lechner's avatar David Lechner Committed by Mark Brown
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spi: axi-spi-engine: add support for any word size 



The AXI SPI Engine IP supports any word size from 1 to 32 bits. This
adds support for this by setting the bits_per_word_mask and emitting
the appropriate instruction to the SPI Engine each time a transfer
requires a new word size.

The functions that transfer tx/rx buffers from/to the SPI Engine
registers (spi_engine_write_{tx,rx}_fifo()) as well as the function that
creates the transfer instruction (spi_engine_gen_xfer()) also have to be
modified to take into account the word size since xfer->len is the
size of the buffers in bytes rather than words.

Signed-off-by: default avatarDavid Lechner <dlechner@baylibre.com>
Link: https://lore.kernel.org/r/20231117-axi-spi-engine-series-1-v1-14-cc59db999b87@baylibre.com


Signed-off-by: default avatarMark Brown <broonie@kernel.org>
parent 145bb2ae

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

+68 −16
Original line number Diff line number Diff line
@@ -53,6 +53,7 @@ 


#define SPI_ENGINE_CMD_REG_CLK_DIV		0x0

#define SPI_ENGINE_CMD_REG_CONFIG		0x1

#define SPI_ENGINE_CMD_REG_XFER_BITS		0x2



#define SPI_ENGINE_MISC_SYNC			0x0

#define SPI_ENGINE_MISC_SLEEP			0x1
@@ -157,7 +158,14 @@ static unsigned int spi_engine_get_clk_div(struct spi_engine *spi_engine, 
static void spi_engine_gen_xfer(struct spi_engine_program *p, bool dry,

	struct spi_transfer *xfer)

{

	unsigned int len = xfer->len;

	unsigned int len;



	if (xfer->bits_per_word <= 8)

		len = xfer->len;

	else if (xfer->bits_per_word <= 16)

		len = xfer->len / 2;

	else

		len = xfer->len / 4;



	while (len) {

		unsigned int n = min(len, 256U);
@@ -217,6 +225,7 @@ static int spi_engine_compile_message(struct spi_engine *spi_engine, 
	struct spi_transfer *xfer;

	int clk_div, new_clk_div;

	bool keep_cs = false;

	u8 bits_per_word = 0;



	clk_div = -1;
@@ -236,6 +245,13 @@ static int spi_engine_compile_message(struct spi_engine *spi_engine, 
					clk_div));

		}



		if (bits_per_word != xfer->bits_per_word) {

			bits_per_word = xfer->bits_per_word;

			spi_engine_program_add_cmd(p, dry,

				SPI_ENGINE_CMD_WRITE(SPI_ENGINE_CMD_REG_XFER_BITS,

					bits_per_word));

		}



		spi_engine_gen_xfer(p, dry, xfer);

		spi_engine_gen_sleep(p, dry, spi_engine, clk_div, xfer);
@@ -342,16 +358,34 @@ static bool spi_engine_write_tx_fifo(struct spi_engine *spi_engine, 
	void __iomem *addr = spi_engine->base + SPI_ENGINE_REG_SDO_DATA_FIFO;

	struct spi_engine_message_state *st = msg->state;

	unsigned int n, m, i;

	const uint8_t *buf;



	n = readl_relaxed(spi_engine->base + SPI_ENGINE_REG_SDO_FIFO_ROOM);

	while (n && st->tx_length) {

		if (st->tx_xfer->bits_per_word <= 8) {

			const u8 *buf = st->tx_buf;



			m = min(n, st->tx_length);

		buf = st->tx_buf;

			for (i = 0; i < m; i++)

				writel_relaxed(buf[i], addr);

			st->tx_buf += m;

			st->tx_length -= m;

		} else if (st->tx_xfer->bits_per_word <= 16) {

			const u16 *buf = (const u16 *)st->tx_buf;



			m = min(n, st->tx_length / 2);

			for (i = 0; i < m; i++)

				writel_relaxed(buf[i], addr);

			st->tx_buf += m * 2;

			st->tx_length -= m * 2;

		} else {

			const u32 *buf = (const u32 *)st->tx_buf;



			m = min(n, st->tx_length / 4);

			for (i = 0; i < m; i++)

				writel_relaxed(buf[i], addr);

			st->tx_buf += m * 4;

			st->tx_length -= m * 4;

		}

		n -= m;

		if (st->tx_length == 0)

			spi_engine_tx_next(msg);
@@ -366,16 +400,34 @@ static bool spi_engine_read_rx_fifo(struct spi_engine *spi_engine, 
	void __iomem *addr = spi_engine->base + SPI_ENGINE_REG_SDI_DATA_FIFO;

	struct spi_engine_message_state *st = msg->state;

	unsigned int n, m, i;

	uint8_t *buf;



	n = readl_relaxed(spi_engine->base + SPI_ENGINE_REG_SDI_FIFO_LEVEL);

	while (n && st->rx_length) {

		if (st->rx_xfer->bits_per_word <= 8) {

			u8 *buf = st->rx_buf;



			m = min(n, st->rx_length);

		buf = st->rx_buf;

			for (i = 0; i < m; i++)

				buf[i] = readl_relaxed(addr);

			st->rx_buf += m;

			st->rx_length -= m;

		} else if (st->rx_xfer->bits_per_word <= 16) {

			u16 *buf = (u16 *)st->rx_buf;



			m = min(n, st->rx_length / 2);

			for (i = 0; i < m; i++)

				buf[i] = readl_relaxed(addr);

			st->rx_buf += m * 2;

			st->rx_length -= m * 2;

		} else {

			u32 *buf = (u32 *)st->rx_buf;



			m = min(n, st->rx_length / 4);

			for (i = 0; i < m; i++)

				buf[i] = readl_relaxed(addr);

			st->rx_buf += m * 4;

			st->rx_length -= m * 4;

		}

		n -= m;

		if (st->rx_length == 0)

			spi_engine_rx_next(msg);
@@ -596,7 +648,7 @@ static int spi_engine_probe(struct platform_device *pdev) 


	host->dev.of_node = pdev->dev.of_node;

	host->mode_bits = SPI_CPOL | SPI_CPHA | SPI_3WIRE;

	host->bits_per_word_mask = SPI_BPW_MASK(8);

	host->bits_per_word_mask = SPI_BPW_RANGE_MASK(1, 32);

	host->max_speed_hz = clk_get_rate(spi_engine->ref_clk) / 2;

	host->transfer_one_message = spi_engine_transfer_one_message;

	host->prepare_message = spi_engine_prepare_message;