xref: /src/sys/arch/arm/sunxi/sunxi_mmc.c

/* $NetBSD: sunxi_mmc.c,v 1.2 2017/07/16 17:12:18 jmcneill Exp $ */

/*-
 * Copyright (c) 2014-2017 Jared McNeill <jmcneill (at) invisible.ca>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND 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 AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: sunxi_mmc.c,v 1.2 2017/07/16 17:12:18 jmcneill Exp $");

#include <sys/param.h>
#include <sys/bus.h>
#include <sys/device.h>
#include <sys/intr.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/gpio.h>

#include <dev/sdmmc/sdmmcvar.h>
#include <dev/sdmmc/sdmmcchip.h>
#include <dev/sdmmc/sdmmc_ioreg.h>

#include <dev/fdt/fdtvar.h>

#include <arm/sunxi/sunxi_mmc.h>

#define SUNXI_MMC_NDESC		16
#define	SUNXI_MMC_DMA_XFERLEN	0x10000
#define	SUNXI_MMC_DMA_FTRGLEVEL	0x20070008

struct sunxi_mmc_softc;

static int	sunxi_mmc_match(device_t, cfdata_t, void *);
static void	sunxi_mmc_attach(device_t, device_t, void *);
static void	sunxi_mmc_attach_i(device_t);

static int	sunxi_mmc_intr(void *);
static int	sunxi_mmc_idma_setup(struct sunxi_mmc_softc *);

static int	sunxi_mmc_host_reset(sdmmc_chipset_handle_t);
static uint32_t	sunxi_mmc_host_ocr(sdmmc_chipset_handle_t);
static int	sunxi_mmc_host_maxblklen(sdmmc_chipset_handle_t);
static int	sunxi_mmc_card_detect(sdmmc_chipset_handle_t);
static int	sunxi_mmc_write_protect(sdmmc_chipset_handle_t);
static int	sunxi_mmc_bus_power(sdmmc_chipset_handle_t, uint32_t);
static int	sunxi_mmc_bus_clock(sdmmc_chipset_handle_t, int);
static int	sunxi_mmc_bus_width(sdmmc_chipset_handle_t, int);
static int	sunxi_mmc_bus_rod(sdmmc_chipset_handle_t, int);
static void	sunxi_mmc_exec_command(sdmmc_chipset_handle_t,
				      struct sdmmc_command *);
static void	sunxi_mmc_card_enable_intr(sdmmc_chipset_handle_t, int);
static void	sunxi_mmc_card_intr_ack(sdmmc_chipset_handle_t);

static struct sdmmc_chip_functions sunxi_mmc_chip_functions = {
	.host_reset = sunxi_mmc_host_reset,
	.host_ocr = sunxi_mmc_host_ocr,
	.host_maxblklen = sunxi_mmc_host_maxblklen,
	.card_detect = sunxi_mmc_card_detect,
	.write_protect = sunxi_mmc_write_protect,
	.bus_power = sunxi_mmc_bus_power,
	.bus_clock = sunxi_mmc_bus_clock,
	.bus_width = sunxi_mmc_bus_width,
	.bus_rod = sunxi_mmc_bus_rod,
	.exec_command = sunxi_mmc_exec_command,
	.card_enable_intr = sunxi_mmc_card_enable_intr,
	.card_intr_ack = sunxi_mmc_card_intr_ack,
};

struct sunxi_mmc_softc {
	device_t sc_dev;
	bus_space_tag_t sc_bst;
	bus_space_handle_t sc_bsh;
	bus_dma_tag_t sc_dmat;
	int sc_phandle;

	void *sc_ih;
	kmutex_t sc_intr_lock;
	kcondvar_t sc_intr_cv;
	kcondvar_t sc_idst_cv;

	int sc_mmc_width;
	int sc_mmc_present;

	device_t sc_sdmmc_dev;

	uint32_t sc_dma_ftrglevel;

	uint32_t sc_idma_xferlen;
	bus_dma_segment_t sc_idma_segs[1];
	int sc_idma_nsegs;
	bus_size_t sc_idma_size;
	bus_dmamap_t sc_idma_map;
	int sc_idma_ndesc;
	void *sc_idma_desc;

	uint32_t sc_intr_rint;
	uint32_t sc_intr_mint;
	uint32_t sc_idma_idst;

	struct clk *sc_clk_ahb;
	struct clk *sc_clk_mmc;
	struct clk *sc_clk_output;
	struct clk *sc_clk_sample;

	struct fdtbus_reset *sc_rst_ahb;

	struct fdtbus_gpio_pin *sc_gpio_cd;
	int sc_gpio_cd_inverted;
	struct fdtbus_gpio_pin *sc_gpio_wp;
	int sc_gpio_wp_inverted;
};

CFATTACH_DECL_NEW(sunxi_mmc, sizeof(struct sunxi_mmc_softc),
	sunxi_mmc_match, sunxi_mmc_attach, NULL, NULL);

#define MMC_WRITE(sc, reg, val)	\
	bus_space_write_4((sc)->sc_bst, (sc)->sc_bsh, (reg), (val))
#define MMC_READ(sc, reg) \
	bus_space_read_4((sc)->sc_bst, (sc)->sc_bsh, (reg))

static const char * const compatible[] = {
	"allwinner,sun7i-a20-mmc",
	NULL
};

static int
sunxi_mmc_match(device_t parent, cfdata_t cf, void *aux)
{
	struct fdt_attach_args * const faa = aux;

	return of_match_compatible(faa->faa_phandle, compatible);
}

static void
sunxi_mmc_attach(device_t parent, device_t self, void *aux)
{
	struct sunxi_mmc_softc * const sc = device_private(self);
	struct fdt_attach_args * const faa = aux;
	const int phandle = faa->faa_phandle;
	char intrstr[128];
	bus_addr_t addr;
	bus_size_t size;

	if (fdtbus_get_reg(phandle, 0, &addr, &size) != 0) {
		aprint_error(": couldn't get registers\n");
		return;
	}

	sc->sc_clk_ahb = fdtbus_clock_get(phandle, "ahb");
	sc->sc_clk_mmc = fdtbus_clock_get(phandle, "mmc");
	sc->sc_clk_output = fdtbus_clock_get(phandle, "output");
	sc->sc_clk_sample = fdtbus_clock_get(phandle, "sample");

#if notyet
	if (sc->sc_clk_ahb == NULL || sc->sc_clk_mmc == NULL ||
	    sc->sc_clk_output == NULL || sc->sc_clk_sample == NULL) {
#else
	if (sc->sc_clk_ahb == NULL || sc->sc_clk_mmc == NULL) {
#endif
		aprint_error(": couldn't get clocks\n");
		return;
	}

	sc->sc_rst_ahb = fdtbus_reset_get(phandle, "ahb");
	if (sc->sc_rst_ahb == NULL) {
		aprint_error(": couldn't get resets\n");
		return;
	}

	if (clk_enable(sc->sc_clk_ahb) != 0 ||
	    clk_enable(sc->sc_clk_mmc) != 0) {
		aprint_error(": couldn't enable clocks\n");
		return;
	}

	if (fdtbus_reset_deassert(sc->sc_rst_ahb) != 0) {
		aprint_error(": couldn't de-assert resets\n");
		return;
	}

	sc->sc_dev = self;
	sc->sc_phandle = phandle;
	sc->sc_bst = faa->faa_bst;
	sc->sc_dmat = faa->faa_dmat;
	mutex_init(&sc->sc_intr_lock, MUTEX_DEFAULT, IPL_BIO);
	cv_init(&sc->sc_intr_cv, "awinmmcirq");
	cv_init(&sc->sc_idst_cv, "awinmmcdma");

	if (bus_space_map(sc->sc_bst, addr, size, 0, &sc->sc_bsh) != 0) {
		aprint_error(": couldn't map registers\n");
		return;
	}

	aprint_naive("\n");
	aprint_normal(": SD/MMC controller\n");

	sc->sc_gpio_cd = fdtbus_gpio_acquire(phandle, "cd-gpios",
	    GPIO_PIN_INPUT);
	sc->sc_gpio_wp = fdtbus_gpio_acquire(phandle, "wp-gpios",
	    GPIO_PIN_INPUT);

	sc->sc_gpio_cd_inverted = of_hasprop(phandle, "cd-inverted") ? 0 : 1;
	sc->sc_gpio_wp_inverted = of_hasprop(phandle, "wp-inverted") ? 0 : 1;

	sc->sc_dma_ftrglevel = SUNXI_MMC_DMA_FTRGLEVEL;

	if (sunxi_mmc_idma_setup(sc) != 0) {
		aprint_error_dev(self, "failed to setup DMA\n");
		return;
	}

	if (!fdtbus_intr_str(phandle, 0, intrstr, sizeof(intrstr))) {
		aprint_error_dev(self, "failed to decode interrupt\n");
		return;
	}

	sc->sc_ih = fdtbus_intr_establish(phandle, 0, IPL_BIO, FDT_INTR_MPSAFE,
	    sunxi_mmc_intr, sc);
	if (sc->sc_ih == NULL) {
		aprint_error_dev(self, "failed to establish interrupt on %s\n",
		    intrstr);
		return;
	}
	aprint_normal_dev(self, "interrupting on %s\n", intrstr);

	config_interrupts(self, sunxi_mmc_attach_i);
}

static int
sunxi_mmc_idma_setup(struct sunxi_mmc_softc *sc)
{
	int error;

	sc->sc_idma_xferlen = SUNXI_MMC_DMA_XFERLEN;

	sc->sc_idma_ndesc = SUNXI_MMC_NDESC;
	sc->sc_idma_size = sizeof(struct sunxi_mmc_idma_descriptor) *
	    sc->sc_idma_ndesc;
	error = bus_dmamem_alloc(sc->sc_dmat, sc->sc_idma_size, 0,
	    sc->sc_idma_size, sc->sc_idma_segs, 1,
	    &sc->sc_idma_nsegs, BUS_DMA_WAITOK);
	if (error)
		return error;
	error = bus_dmamem_map(sc->sc_dmat, sc->sc_idma_segs,
	    sc->sc_idma_nsegs, sc->sc_idma_size,
	    &sc->sc_idma_desc, BUS_DMA_WAITOK);
	if (error)
		goto free;
	error = bus_dmamap_create(sc->sc_dmat, sc->sc_idma_size, 1,
	    sc->sc_idma_size, 0, BUS_DMA_WAITOK, &sc->sc_idma_map);
	if (error)
		goto unmap;
	error = bus_dmamap_load(sc->sc_dmat, sc->sc_idma_map,
	    sc->sc_idma_desc, sc->sc_idma_size, NULL, BUS_DMA_WAITOK);
	if (error)
		goto destroy;
	return 0;

destroy:
	bus_dmamap_destroy(sc->sc_dmat, sc->sc_idma_map);
unmap:
	bus_dmamem_unmap(sc->sc_dmat, sc->sc_idma_desc, sc->sc_idma_size);
free:
	bus_dmamem_free(sc->sc_dmat, sc->sc_idma_segs, sc->sc_idma_nsegs);
	return error;
}

static int
sunxi_mmc_set_clock(struct sunxi_mmc_softc *sc, u_int freq)
{
	return clk_set_rate(sc->sc_clk_mmc, freq * 1000);
}

static void
sunxi_mmc_attach_i(device_t self)
{
	struct sunxi_mmc_softc *sc = device_private(self);
	struct sdmmcbus_attach_args saa;
	uint32_t width;

	sunxi_mmc_host_reset(sc);
	sunxi_mmc_bus_width(sc, 1);
	sunxi_mmc_set_clock(sc, 400);

	if (of_getprop_uint32(sc->sc_phandle, "bus-width", &width) != 0)
		width = 4;

	memset(&saa, 0, sizeof(saa));
	saa.saa_busname = "sdmmc";
	saa.saa_sct = &sunxi_mmc_chip_functions;
	saa.saa_sch = sc;
	saa.saa_dmat = sc->sc_dmat;
	saa.saa_clkmin = 400;
	saa.saa_clkmax = 52000;
	saa.saa_caps = SMC_CAPS_DMA |
		       SMC_CAPS_MULTI_SEG_DMA |
		       SMC_CAPS_AUTO_STOP |
		       SMC_CAPS_SD_HIGHSPEED |
		       SMC_CAPS_MMC_HIGHSPEED |
		       SMC_CAPS_POLLING;
	if (width == 4)
		saa.saa_caps |= SMC_CAPS_4BIT_MODE;
	if (width == 8)
		saa.saa_caps |= SMC_CAPS_8BIT_MODE;

	if (sc->sc_gpio_cd)
		saa.saa_caps |= SMC_CAPS_POLL_CARD_DET;

	sc->sc_sdmmc_dev = config_found(self, &saa, NULL);
}

static int
sunxi_mmc_intr(void *priv)
{
	struct sunxi_mmc_softc *sc = priv;
	uint32_t idst, rint, mint;

	mutex_enter(&sc->sc_intr_lock);
	idst = MMC_READ(sc, SUNXI_MMC_IDST);
	rint = MMC_READ(sc, SUNXI_MMC_RINT);
	mint = MMC_READ(sc, SUNXI_MMC_MINT);
	if (!idst && !rint && !mint) {
		mutex_exit(&sc->sc_intr_lock);
		return 0;
	}
	MMC_WRITE(sc, SUNXI_MMC_IDST, idst);
	MMC_WRITE(sc, SUNXI_MMC_RINT, rint);
	MMC_WRITE(sc, SUNXI_MMC_MINT, mint);

#ifdef SUNXI_MMC_DEBUG
	device_printf(sc->sc_dev, "mmc intr idst=%08X rint=%08X mint=%08X\n",
	    idst, rint, mint);
#endif

	if (idst) {
		sc->sc_idma_idst |= idst;
		cv_broadcast(&sc->sc_idst_cv);
	}

	if (rint) {
		sc->sc_intr_rint |= rint;
		cv_broadcast(&sc->sc_intr_cv);
	}

	mutex_exit(&sc->sc_intr_lock);

	return 1;
}

static int
sunxi_mmc_wait_rint(struct sunxi_mmc_softc *sc, uint32_t mask,
    int timeout, bool poll)
{
	int retry;
	int error;

	KASSERT(mutex_owned(&sc->sc_intr_lock));

	if (sc->sc_intr_rint & mask)
		return 0;

	if (poll)
		retry = timeout / hz * 1000;
	else
		retry = timeout / hz;

	while (retry > 0) {
		if (poll) {
			sc->sc_intr_rint |= MMC_READ(sc, SUNXI_MMC_RINT);
		} else {
			error = cv_timedwait(&sc->sc_intr_cv,
			    &sc->sc_intr_lock, hz);
			if (error && error != EWOULDBLOCK)
				return error;
		}
		if (sc->sc_intr_rint & mask)
			return 0;
		if (poll)
			delay(1000);
		--retry;
	}

	return ETIMEDOUT;
}

static int
sunxi_mmc_host_reset(sdmmc_chipset_handle_t sch)
{
	struct sunxi_mmc_softc *sc = sch;
	int retry = 1000;

#ifdef SUNXI_MMC_DEBUG
	aprint_normal_dev(sc->sc_dev, "host reset\n");
#endif

	MMC_WRITE(sc, SUNXI_MMC_GCTRL,
	    MMC_READ(sc, SUNXI_MMC_GCTRL) | SUNXI_MMC_GCTRL_RESET);
	while (--retry > 0) {
		if (!(MMC_READ(sc, SUNXI_MMC_GCTRL) & SUNXI_MMC_GCTRL_RESET))
			break;
		delay(100);
	}

	MMC_WRITE(sc, SUNXI_MMC_TIMEOUT, 0xffffffff);

	MMC_WRITE(sc, SUNXI_MMC_IMASK,
	    SUNXI_MMC_INT_CMD_DONE | SUNXI_MMC_INT_ERROR |
	    SUNXI_MMC_INT_DATA_OVER | SUNXI_MMC_INT_AUTO_CMD_DONE);

	MMC_WRITE(sc, SUNXI_MMC_GCTRL,
	    MMC_READ(sc, SUNXI_MMC_GCTRL) | SUNXI_MMC_GCTRL_INTEN);

	return 0;
}

static uint32_t
sunxi_mmc_host_ocr(sdmmc_chipset_handle_t sch)
{
	return MMC_OCR_3_2V_3_3V | MMC_OCR_3_3V_3_4V | MMC_OCR_HCS;
}

static int
sunxi_mmc_host_maxblklen(sdmmc_chipset_handle_t sch)
{
	return 8192;
}

static int
sunxi_mmc_card_detect(sdmmc_chipset_handle_t sch)
{
	struct sunxi_mmc_softc *sc = sch;

	if (sc->sc_gpio_cd == NULL) {
		return 1;	/* no card detect pin, assume present */
	} else {
		int v = 0, i;
		for (i = 0; i < 5; i++) {
			v += (fdtbus_gpio_read(sc->sc_gpio_cd) ^
			    sc->sc_gpio_cd_inverted);
			delay(1000);
		}
		if (v == 5)
			sc->sc_mmc_present = 0;
		else if (v == 0)
			sc->sc_mmc_present = 1;
		return sc->sc_mmc_present;
	}
}

static int
sunxi_mmc_write_protect(sdmmc_chipset_handle_t sch)
{
	struct sunxi_mmc_softc *sc = sch;

	if (sc->sc_gpio_wp == NULL) {
		return 0;	/* no write protect pin, assume rw */
	} else {
		return fdtbus_gpio_read(sc->sc_gpio_wp) ^
		    sc->sc_gpio_wp_inverted;
	}
}

static int
sunxi_mmc_bus_power(sdmmc_chipset_handle_t sch, uint32_t ocr)
{
	return 0;
}

static int
sunxi_mmc_update_clock(struct sunxi_mmc_softc *sc)
{
	uint32_t cmd;
	int retry;

#ifdef SUNXI_MMC_DEBUG
	aprint_normal_dev(sc->sc_dev, "update clock\n");
#endif

	cmd = SUNXI_MMC_CMD_START |
	      SUNXI_MMC_CMD_UPCLK_ONLY |
	      SUNXI_MMC_CMD_WAIT_PRE_OVER;
	MMC_WRITE(sc, SUNXI_MMC_CMD, cmd);
	retry = 0xfffff;
	while (--retry > 0) {
		if (!(MMC_READ(sc, SUNXI_MMC_CMD) & SUNXI_MMC_CMD_START))
			break;
		delay(10);
	}

	if (retry == 0) {
		aprint_error_dev(sc->sc_dev, "timeout updating clock\n");
#ifdef SUNXI_MMC_DEBUG
		device_printf(sc->sc_dev, "GCTRL: 0x%08x\n",
		    MMC_READ(sc, SUNXI_MMC_GCTRL));
		device_printf(sc->sc_dev, "CLKCR: 0x%08x\n",
		    MMC_READ(sc, SUNXI_MMC_CLKCR));
		device_printf(sc->sc_dev, "TIMEOUT: 0x%08x\n",
		    MMC_READ(sc, SUNXI_MMC_TIMEOUT));
		device_printf(sc->sc_dev, "WIDTH: 0x%08x\n",
		    MMC_READ(sc, SUNXI_MMC_WIDTH));
		device_printf(sc->sc_dev, "CMD: 0x%08x\n",
		    MMC_READ(sc, SUNXI_MMC_CMD));
		device_printf(sc->sc_dev, "MINT: 0x%08x\n",
		    MMC_READ(sc, SUNXI_MMC_MINT));
		device_printf(sc->sc_dev, "RINT: 0x%08x\n",
		    MMC_READ(sc, SUNXI_MMC_RINT));
		device_printf(sc->sc_dev, "STATUS: 0x%08x\n",
		    MMC_READ(sc, SUNXI_MMC_STATUS));
#endif
		return ETIMEDOUT;
	}

	return 0;
}

static int
sunxi_mmc_bus_clock(sdmmc_chipset_handle_t sch, int freq)
{
	struct sunxi_mmc_softc *sc = sch;
	uint32_t clkcr;

	clkcr = MMC_READ(sc, SUNXI_MMC_CLKCR);
	if (clkcr & SUNXI_MMC_CLKCR_CARDCLKON) {
		clkcr &= ~SUNXI_MMC_CLKCR_CARDCLKON;
		MMC_WRITE(sc, SUNXI_MMC_CLKCR, clkcr);
		if (sunxi_mmc_update_clock(sc) != 0)
			return 1;
	}

	if (freq) {

		clkcr &= ~SUNXI_MMC_CLKCR_DIV;
		MMC_WRITE(sc, SUNXI_MMC_CLKCR, clkcr);
		if (sunxi_mmc_update_clock(sc) != 0)
			return 1;

		if (sunxi_mmc_set_clock(sc, freq) != 0)
			return 1;

		clkcr |= SUNXI_MMC_CLKCR_CARDCLKON;
		MMC_WRITE(sc, SUNXI_MMC_CLKCR, clkcr);
		if (sunxi_mmc_update_clock(sc) != 0)
			return 1;
	}

	return 0;
}

static int
sunxi_mmc_bus_width(sdmmc_chipset_handle_t sch, int width)
{
	struct sunxi_mmc_softc *sc = sch;

#ifdef SUNXI_MMC_DEBUG
	aprint_normal_dev(sc->sc_dev, "width = %d\n", width);
#endif

	switch (width) {
	case 1:
		MMC_WRITE(sc, SUNXI_MMC_WIDTH, SUNXI_MMC_WIDTH_1);
		break;
	case 4:
		MMC_WRITE(sc, SUNXI_MMC_WIDTH, SUNXI_MMC_WIDTH_4);
		break;
	case 8:
		MMC_WRITE(sc, SUNXI_MMC_WIDTH, SUNXI_MMC_WIDTH_8);
		break;
	default:
		return 1;
	}

	sc->sc_mmc_width = width;

	return 0;
}

static int
sunxi_mmc_bus_rod(sdmmc_chipset_handle_t sch, int on)
{
	return -1;
}

static int
sunxi_mmc_dma_prepare(struct sunxi_mmc_softc *sc, struct sdmmc_command *cmd)
{
	struct sunxi_mmc_idma_descriptor *dma = sc->sc_idma_desc;
	bus_addr_t desc_paddr = sc->sc_idma_map->dm_segs[0].ds_addr;
	bus_size_t off;
	int desc, resid, seg;
	uint32_t val;

	desc = 0;
	for (seg = 0; seg < cmd->c_dmamap->dm_nsegs; seg++) {
		bus_addr_t paddr = cmd->c_dmamap->dm_segs[seg].ds_addr;
		bus_size_t len = cmd->c_dmamap->dm_segs[seg].ds_len;
		resid = min(len, cmd->c_resid);
		off = 0;
		while (resid > 0) {
			if (desc == sc->sc_idma_ndesc)
				break;
			len = min(sc->sc_idma_xferlen, resid);
			dma[desc].dma_buf_size = htole32(len);
			dma[desc].dma_buf_addr = htole32(paddr + off);
			dma[desc].dma_config = htole32(SUNXI_MMC_IDMA_CONFIG_CH |
					       SUNXI_MMC_IDMA_CONFIG_OWN);
			cmd->c_resid -= len;
			resid -= len;
			off += len;
			if (desc == 0) {
				dma[desc].dma_config |= htole32(SUNXI_MMC_IDMA_CONFIG_FD);
			}
			if (cmd->c_resid == 0) {
				dma[desc].dma_config |= htole32(SUNXI_MMC_IDMA_CONFIG_LD);
				dma[desc].dma_config |= htole32(SUNXI_MMC_IDMA_CONFIG_ER);
				dma[desc].dma_next = 0;
			} else {
				dma[desc].dma_config |=
				    htole32(SUNXI_MMC_IDMA_CONFIG_DIC);
				dma[desc].dma_next = htole32(
				    desc_paddr + ((desc+1) *
				    sizeof(struct sunxi_mmc_idma_descriptor)));
			}
			++desc;
		}
	}
	if (desc == sc->sc_idma_ndesc) {
		aprint_error_dev(sc->sc_dev,
		    "not enough descriptors for %d byte transfer!\n",
		    cmd->c_datalen);
		return EIO;
	}

	bus_dmamap_sync(sc->sc_dmat, sc->sc_idma_map, 0,
	    sc->sc_idma_size, BUS_DMASYNC_PREWRITE);

	sc->sc_idma_idst = 0;

	val = MMC_READ(sc, SUNXI_MMC_GCTRL);
	val |= SUNXI_MMC_GCTRL_DMAEN;
	val |= SUNXI_MMC_GCTRL_INTEN;
	MMC_WRITE(sc, SUNXI_MMC_GCTRL, val);
	val |= SUNXI_MMC_GCTRL_DMARESET;
	MMC_WRITE(sc, SUNXI_MMC_GCTRL, val);
	MMC_WRITE(sc, SUNXI_MMC_DMAC, SUNXI_MMC_DMAC_SOFTRESET);
	MMC_WRITE(sc, SUNXI_MMC_DMAC,
	    SUNXI_MMC_DMAC_IDMA_ON|SUNXI_MMC_DMAC_FIX_BURST);
	val = MMC_READ(sc, SUNXI_MMC_IDIE);
	val &= ~(SUNXI_MMC_IDST_RECEIVE_INT|SUNXI_MMC_IDST_TRANSMIT_INT);
	if (cmd->c_flags & SCF_CMD_READ)
		val |= SUNXI_MMC_IDST_RECEIVE_INT;
	else
		val |= SUNXI_MMC_IDST_TRANSMIT_INT;
	MMC_WRITE(sc, SUNXI_MMC_IDIE, val);
	MMC_WRITE(sc, SUNXI_MMC_DLBA, desc_paddr);
	MMC_WRITE(sc, SUNXI_MMC_FTRGLEVEL, sc->sc_dma_ftrglevel);

	return 0;
}

static void
sunxi_mmc_dma_complete(struct sunxi_mmc_softc *sc)
{
	bus_dmamap_sync(sc->sc_dmat, sc->sc_idma_map, 0,
	    sc->sc_idma_size, BUS_DMASYNC_POSTWRITE);
}

static void
sunxi_mmc_exec_command(sdmmc_chipset_handle_t sch, struct sdmmc_command *cmd)
{
	struct sunxi_mmc_softc *sc = sch;
	uint32_t cmdval = SUNXI_MMC_CMD_START;
	const bool poll = (cmd->c_flags & SCF_POLL) != 0;
	int retry;

#ifdef SUNXI_MMC_DEBUG
	aprint_normal_dev(sc->sc_dev,
	    "opcode %d flags 0x%x data %p datalen %d blklen %d poll %d\n",
	    cmd->c_opcode, cmd->c_flags, cmd->c_data, cmd->c_datalen,
	    cmd->c_blklen, poll);
#endif

	mutex_enter(&sc->sc_intr_lock);

	if (cmd->c_opcode == 0)
		cmdval |= SUNXI_MMC_CMD_SEND_INIT_SEQ;
	if (cmd->c_flags & SCF_RSP_PRESENT)
		cmdval |= SUNXI_MMC_CMD_RSP_EXP;
	if (cmd->c_flags & SCF_RSP_136)
		cmdval |= SUNXI_MMC_CMD_LONG_RSP;
	if (cmd->c_flags & SCF_RSP_CRC)
		cmdval |= SUNXI_MMC_CMD_CHECK_RSP_CRC;

	if (cmd->c_datalen > 0) {
		unsigned int nblks;

		cmdval |= SUNXI_MMC_CMD_DATA_EXP | SUNXI_MMC_CMD_WAIT_PRE_OVER;
		if (!ISSET(cmd->c_flags, SCF_CMD_READ)) {
			cmdval |= SUNXI_MMC_CMD_WRITE;
		}

		nblks = cmd->c_datalen / cmd->c_blklen;
		if (nblks == 0 || (cmd->c_datalen % cmd->c_blklen) != 0)
			++nblks;

		if (nblks > 1) {
			cmdval |= SUNXI_MMC_CMD_SEND_AUTO_STOP;
		}

		MMC_WRITE(sc, SUNXI_MMC_BLKSZ, cmd->c_blklen);
		MMC_WRITE(sc, SUNXI_MMC_BYTECNT, nblks * cmd->c_blklen);
	}

	sc->sc_intr_rint = 0;

	MMC_WRITE(sc, SUNXI_MMC_A12A,
	    (cmdval & SUNXI_MMC_CMD_SEND_AUTO_STOP) ? 0 : 0xffff);

	MMC_WRITE(sc, SUNXI_MMC_ARG, cmd->c_arg);

#ifdef SUNXI_MMC_DEBUG
	aprint_normal_dev(sc->sc_dev, "cmdval = %08x\n", cmdval);
#endif

	if (cmd->c_datalen == 0) {
		MMC_WRITE(sc, SUNXI_MMC_CMD, cmdval | cmd->c_opcode);
	} else {
		cmd->c_resid = cmd->c_datalen;
		cmd->c_error = sunxi_mmc_dma_prepare(sc, cmd);
		MMC_WRITE(sc, SUNXI_MMC_CMD, cmdval | cmd->c_opcode);
		if (cmd->c_error == 0) {
			const uint32_t idst_mask =
			    SUNXI_MMC_IDST_ERROR | SUNXI_MMC_IDST_COMPLETE;
			retry = 10;
			while ((sc->sc_idma_idst & idst_mask) == 0) {
				if (retry-- == 0) {
					cmd->c_error = ETIMEDOUT;
					break;
				}
				cv_timedwait(&sc->sc_idst_cv,
				    &sc->sc_intr_lock, hz);
			}
		}
		sunxi_mmc_dma_complete(sc);
		if (sc->sc_idma_idst & SUNXI_MMC_IDST_ERROR) {
			cmd->c_error = EIO;
		} else if (!(sc->sc_idma_idst & SUNXI_MMC_IDST_COMPLETE)) {
			cmd->c_error = ETIMEDOUT;
		}
		if (cmd->c_error) {
#ifdef SUNXI_MMC_DEBUG
			aprint_error_dev(sc->sc_dev,
			    "xfer failed, error %d\n", cmd->c_error);
#endif
			goto done;
		}
	}

	cmd->c_error = sunxi_mmc_wait_rint(sc,
	    SUNXI_MMC_INT_ERROR|SUNXI_MMC_INT_CMD_DONE, hz * 10, poll);
	if (cmd->c_error == 0 && (sc->sc_intr_rint & SUNXI_MMC_INT_ERROR)) {
		if (sc->sc_intr_rint & SUNXI_MMC_INT_RESP_TIMEOUT) {
			cmd->c_error = ETIMEDOUT;
		} else {
			cmd->c_error = EIO;
		}
	}
	if (cmd->c_error) {
#ifdef SUNXI_MMC_DEBUG
		aprint_error_dev(sc->sc_dev,
		    "cmd failed, error %d\n", cmd->c_error);
#endif
		goto done;
	}

	if (cmd->c_datalen > 0) {
		cmd->c_error = sunxi_mmc_wait_rint(sc,
		    SUNXI_MMC_INT_ERROR|
		    SUNXI_MMC_INT_AUTO_CMD_DONE|
		    SUNXI_MMC_INT_DATA_OVER,
		    hz*10, poll);
		if (cmd->c_error == 0 &&
		    (sc->sc_intr_rint & SUNXI_MMC_INT_ERROR)) {
			cmd->c_error = ETIMEDOUT;
		}
		if (cmd->c_error) {
#ifdef SUNXI_MMC_DEBUG
			aprint_error_dev(sc->sc_dev,
			    "data timeout, rint = %08x\n",
			    sc->sc_intr_rint);
#endif
			cmd->c_error = ETIMEDOUT;
			goto done;
		}
	}

	if (cmd->c_flags & SCF_RSP_PRESENT) {
		if (cmd->c_flags & SCF_RSP_136) {
			cmd->c_resp[0] = MMC_READ(sc, SUNXI_MMC_RESP0);
			cmd->c_resp[1] = MMC_READ(sc, SUNXI_MMC_RESP1);
			cmd->c_resp[2] = MMC_READ(sc, SUNXI_MMC_RESP2);
			cmd->c_resp[3] = MMC_READ(sc, SUNXI_MMC_RESP3);
			if (cmd->c_flags & SCF_RSP_CRC) {
				cmd->c_resp[0] = (cmd->c_resp[0] >> 8) |
				    (cmd->c_resp[1] << 24);
				cmd->c_resp[1] = (cmd->c_resp[1] >> 8) |
				    (cmd->c_resp[2] << 24);
				cmd->c_resp[2] = (cmd->c_resp[2] >> 8) |
				    (cmd->c_resp[3] << 24);
				cmd->c_resp[3] = (cmd->c_resp[3] >> 8);
			}
		} else {
			cmd->c_resp[0] = MMC_READ(sc, SUNXI_MMC_RESP0);
		}
	}

done:
	cmd->c_flags |= SCF_ITSDONE;
	mutex_exit(&sc->sc_intr_lock);

	if (cmd->c_error) {
#ifdef SUNXI_MMC_DEBUG
		aprint_error_dev(sc->sc_dev, "i/o error %d\n", cmd->c_error);
#endif
		MMC_WRITE(sc, SUNXI_MMC_GCTRL,
		    MMC_READ(sc, SUNXI_MMC_GCTRL) |
		      SUNXI_MMC_GCTRL_DMARESET | SUNXI_MMC_GCTRL_FIFORESET);
		for (retry = 0; retry < 1000; retry++) {
			if (!(MMC_READ(sc, SUNXI_MMC_GCTRL) & SUNXI_MMC_GCTRL_RESET))
				break;
			delay(10);
		}
		sunxi_mmc_update_clock(sc);
	}

	MMC_WRITE(sc, SUNXI_MMC_GCTRL,
	    MMC_READ(sc, SUNXI_MMC_GCTRL) | SUNXI_MMC_GCTRL_FIFORESET);
}

static void
sunxi_mmc_card_enable_intr(sdmmc_chipset_handle_t sch, int enable)
{
}

static void
sunxi_mmc_card_intr_ack(sdmmc_chipset_handle_t sch)
{
}