xref: /src/sys/dev/marvell/mvspi.c

/*******************************************************************************
Copyright (C) Marvell International Ltd. and its affiliates

Developed by Semihalf

********************************************************************************
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    *   Redistributions of source code must retain the above copyright notice,
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        notice, this list of conditions and the following disclaimer in the
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    *   Neither the name of Marvell nor the names of its contributors may be
        used to endorse or promote products derived from this software without
        specific prior written permission.

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ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
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(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

*******************************************************************************/

/*
 * Transfer mechanism extracted from arspi.c corresponding with the lines
 * 254-262 in this file.
 */

#include <sys/param.h>
#include <sys/device.h>

#include <dev/spi/spivar.h>

#include <dev/marvell/mvspireg.h>
#include <dev/marvell/marvellvar.h>

#include "locators.h"

extern uint32_t mvTclk;

struct mvspi_softc {
	struct spi_controller	sc_spi;
	void			*sc_ih;
	bool			sc_interrupts;

	struct spi_transfer	*sc_transfer;
	struct spi_chunk	*sc_wchunk;	/* For partial writes */
	struct spi_transq	sc_transq;
	bus_space_tag_t		sc_st;
	bus_space_handle_t	sc_sh;
	bus_size_t		sc_size;
};

int mvspi_match(struct device *, struct cfdata *, void *);
void mvspi_attach(struct device *, struct device *, void *);
/* SPI service routines */
int mvspi_configure(void *, int, int, int);
int mvspi_transfer(void *, struct spi_transfer *);
/* Internal support */
void mvspi_sched(struct mvspi_softc *);
void mvspi_assert(struct mvspi_softc *sc);
void mvspi_deassert(struct mvspi_softc *sc);

#define	GETREG(sc, x)					\
	bus_space_read_4(sc->sc_st, sc->sc_sh, x)
#define	PUTREG(sc, x, v)				\
	bus_space_write_4(sc->sc_st, sc->sc_sh, x, v)

/* Attach structure */
CFATTACH_DECL_NEW(mvspi_mbus, sizeof(struct mvspi_softc),
    mvspi_match, mvspi_attach, NULL, NULL);

int
mvspi_match(struct device *parent, struct cfdata *cf, void *aux)
{
	struct marvell_attach_args *mva = aux;

	if (strcmp(mva->mva_name, cf->cf_name) != 0)
		return 0;
	if (mva->mva_offset == MVA_OFFSET_DEFAULT ||
	    mva->mva_irq == MVA_IRQ_DEFAULT)
		return 0;

	mva->mva_size = MVSPI_SIZE;
	return 1;
}

void
mvspi_attach(struct device *parent, struct device *self, void *aux)
{
	struct mvspi_softc *sc =  device_private(self);
  	struct marvell_attach_args *mva = aux;
	int ctl;

	aprint_normal(": Marvell SPI controller\n");

	/*
	 * Map registers.
	 */
	sc->sc_st = mva->mva_iot;
	sc->sc_size = mva->mva_size;

	if (bus_space_subregion(sc->sc_st, mva->mva_ioh, mva->mva_offset,
	    mva->mva_size, &sc->sc_sh)) {
		aprint_error_dev(self, "Cannot map registers\n");
		return;
	}

	/*
	 * Initialize hardware.
	 */
	ctl = GETREG(sc, MVSPI_INTCONF_REG);

	ctl &= MVSPI_DIRHS_MASK;
	ctl &= MVSPI_1BYTE_MASK;

	PUTREG(sc, MVSPI_INTCONF_REG, ctl);

	/*
	 * Initialize SPI controller.
	 */
	sc->sc_spi.sct_cookie = sc;
	sc->sc_spi.sct_configure = mvspi_configure;
	sc->sc_spi.sct_transfer = mvspi_transfer;
	sc->sc_spi.sct_nslaves = 1;

	/*
	 * Initialize the queue.
	 */
	spi_transq_init(&sc->sc_transq);

	/*
	 * Initialize and attach bus attach.
	 */
	spibus_attach(self, &sc->sc_spi);
}

int
mvspi_configure(void *cookie, int slave, int mode, int speed)
{
	struct mvspi_softc *sc = cookie;
	uint32_t ctl = 0, spr, sppr;
	uint32_t divider;
	uint32_t best_spr = 0, best_sppr = 0;
	uint32_t best_sppr0, best_spprhi;
	uint8_t exact_match = 0;
	uint32_t min_baud_offset = 0xFFFFFFFF;

	if (slave < 0 || slave > 7)
		return EINVAL;

	switch(mode) {
		case SPI_MODE_0:
			ctl &= ~(MVSPI_CPOL_MASK);
			/* In boards documentation, CPHA is inverted */
			ctl &= MVSPI_CPHA_MASK;
			break;
		case SPI_MODE_1:
			ctl |= MVSPI_CPOL_MASK;
			ctl &= MVSPI_CPHA_MASK;
			break;
		case SPI_MODE_2:
			ctl &= ~(MVSPI_CPOL_MASK);
			ctl |= ~(MVSPI_CPHA_MASK);
			break;
		case SPI_MODE_3:
			ctl |= MVSPI_CPOL_MASK;
			ctl |= ~(MVSPI_CPHA_MASK);
			break;
		default:
			return EINVAL;
	}

	/* Find the best prescale configuration - less or equal:
	 * SPI actual frequency = core_clk / (SPR * (2 ^ SPPR))
	 * Try to find the minimal SPR and SPPR values that offer
	 * the best prescale config.
	 *
	 */
	for (spr = 1; spr <= MVSPI_SPR_MAXVALUE; spr++) {
		for (sppr = 0; sppr <= MVSPI_SPPR_MAXVALUE; sppr++) {
			divider = spr * (1 << sppr);
			/* Check for higher - irrelevant */
			if ((mvTclk / divider) > speed)
				continue;

			/* Check for exact fit */
			if ((mvTclk / divider) == speed) {
				best_spr = spr;
				best_sppr = sppr;
				exact_match = 1;
				break;
			}

			/* Check if this is better than the previous one */
			if ((speed - (mvTclk / divider)) < min_baud_offset) {
				min_baud_offset = (speed - (mvTclk / divider));
				best_spr = spr;
				best_sppr = sppr;
			}
		}

		if (exact_match == 1)
			break;
	}

	if (best_spr == 0) {
		printf("%s ERROR: SPI baud rate prescale error!\n", __func__);
		return -1;
	}

	ctl &= ~(MVSPI_SPR_MASK);
	ctl &= ~(MVSPI_SPPR_MASK);
	ctl |= best_spr;

	best_spprhi = best_sppr & MVSPI_SPPRHI_MASK;
	best_spprhi = best_spprhi << 5;

	ctl |= best_spprhi;

	best_sppr0 = best_sppr & MVSPI_SPPR0_MASK;
	best_sppr0 = best_sppr0 << 4;

	ctl |= best_sppr0;

	PUTREG(sc, MVSPI_INTCONF_REG, ctl);

	return 0;
}

int
mvspi_transfer(void *cookie, struct spi_transfer *st)
{
	struct mvspi_softc *sc = cookie;
	int s;

	s = splbio();
	spi_transq_enqueue(&sc->sc_transq, st);
	if (sc->sc_transfer == NULL) {
		mvspi_sched(sc);
	}
	splx(s);
	return 0;
}

void
mvspi_assert(struct mvspi_softc *sc)
{
	int ctl;

	if (sc->sc_transfer->st_slave < 0 || sc->sc_transfer->st_slave > 7) {
		printf("%s ERROR: Slave number %d not valid!\n",  __func__, sc->sc_transfer->st_slave);
		return;
	} else
		/* Enable appropriate CSn according to its slave number */
		PUTREG(sc, MVSPI_CTRL_REG, (sc->sc_transfer->st_slave << 2));

	/* Enable CSnAct */
	ctl = GETREG(sc, MVSPI_CTRL_REG);
	ctl |= MVSPI_CSNACT_MASK;
	PUTREG(sc, MVSPI_CTRL_REG, ctl);
}

void
mvspi_deassert(struct mvspi_softc *sc)
{
	int ctl = GETREG(sc, MVSPI_CTRL_REG);
	ctl &= ~(MVSPI_CSNACT_MASK);
	PUTREG(sc, MVSPI_CTRL_REG, ctl);
}

void
mvspi_sched(struct mvspi_softc *sc)
{
	struct spi_transfer *st;
	struct spi_chunk *chunk;
	int i, j, ctl;
	uint8_t byte;
	int ready = FALSE;

	for (;;) {
		if ((st = sc->sc_transfer) == NULL) {
			if ((st = spi_transq_first(&sc->sc_transq)) == NULL) {
				/* No work left to do */
				break;
			}
			spi_transq_dequeue(&sc->sc_transq);
			sc->sc_transfer = st;
		}

		chunk = st->st_chunks;

		mvspi_assert(sc);

		do {
			for (i = chunk->chunk_wresid; i > 0; i--) {
				/* First clear the ready bit */
				ctl = GETREG(sc, MVSPI_CTRL_REG);
				ctl &= ~(MVSPI_CR_SMEMRDY);
				PUTREG(sc, MVSPI_CTRL_REG, ctl);

				if (chunk->chunk_wptr){
					byte = *chunk->chunk_wptr;
					chunk->chunk_wptr++;
				} else
					byte = MVSPI_DUMMY_BYTE;

				/* Transmit data */
				PUTREG(sc, MVSPI_DATAOUT_REG, byte);

				/* Wait with timeout for memory ready */
				for (j = 0; j < MVSPI_WAIT_RDY_MAX_LOOP; j++) {
					if (GETREG(sc, MVSPI_CTRL_REG) &
						MVSPI_CR_SMEMRDY) {
						ready = TRUE;
						break;
					}

				}

				if (!ready) {
					mvspi_deassert(sc);
					spi_done(st, EBUSY);
					return;
				}

				/* Check that the RX data is needed */
				if (chunk->chunk_rptr) {
					*chunk->chunk_rptr =
						GETREG(sc, MVSPI_DATAIN_REG);
					chunk->chunk_rptr++;

				}

			}

			chunk = chunk->chunk_next;

		} while (chunk != NULL);

		mvspi_deassert(sc);

		spi_done(st, 0);
		sc->sc_transfer = NULL;


		break;
	}
}