rpi3: Add SDHost driver

This commit adds SDHost driver for RaspberryPi3. SDHost driver uses the
GPIO driver to connect the SDCard and SDHost. By using this driver it is
able to read/write raw blocks on SDCard.
Signed-off-by: Ying-Chun Liu (PaulLiu) <paulliu@debian.org>

drivers/rpi3/sdhost/rpi3_sdhost.c

+/*
+ * Copyright (c) 2019, Linaro Limited
+ * Copyright (c) 2019, Ying-Chun Liu (PaulLiu) <paul.liu@linaro.org>
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <arch.h>
+#include <arch_helpers.h>
+#include <assert.h>
+#include <common/debug.h>
+#include <lib/mmio.h>
+#include <drivers/delay_timer.h>
+#include <drivers/rpi3/sdhost/rpi3_sdhost.h>
+#include <drivers/mmc.h>
+#include <drivers/rpi3/gpio/rpi3_gpio.h>
+#include <errno.h>
+#include <string.h>
+
+static void rpi3_sdhost_initialize(void);
+static int rpi3_sdhost_send_cmd(struct mmc_cmd *cmd);
+static int rpi3_sdhost_set_ios(unsigned int clk, unsigned int width);
+static int rpi3_sdhost_prepare(int lba, uintptr_t buf, size_t size);
+static int rpi3_sdhost_read(int lba, uintptr_t buf, size_t size);
+static int rpi3_sdhost_write(int lba, uintptr_t buf, size_t size);
+
+static const struct mmc_ops rpi3_sdhost_ops = {
+	.init		= rpi3_sdhost_initialize,
+	.send_cmd	= rpi3_sdhost_send_cmd,
+	.set_ios	= rpi3_sdhost_set_ios,
+	.prepare	= rpi3_sdhost_prepare,
+	.read		= rpi3_sdhost_read,
+	.write		= rpi3_sdhost_write,
+};
+
+static struct rpi3_sdhost_params rpi3_sdhost_params;
+
+/**
+ * Wait for command being processed.
+ *
+ * This function waits the command being processed. It compares
+ * the ENABLE flag of the HC_COMMAND register. When ENABLE flag disappeared
+ * it means the command is processed by the SDHOST.
+ * The timeout is currently 1000*100 us = 100 ms.
+ *
+ * @return 0: command finished. 1: command timed out.
+ */
+static int rpi3_sdhost_waitcommand(void)
+{
+	uintptr_t reg_base = rpi3_sdhost_params.reg_base;
+
+	volatile int timeout = 1000;
+
+	while ((mmio_read_32(reg_base + HC_COMMAND) & HC_CMD_ENABLE)
+	       && (--timeout > 0)) {
+		udelay(100);
+	}
+
+	return ((timeout > 0) ? 0 : (-(ETIMEDOUT)));
+}
+
+/**
+ * Send the command and argument to the SDHOST
+ *
+ * This function will wait for the previous command finished. And then
+ * clear any error status of previous command. And then
+ * send out the command and args. The command will be turned on the ENABLE
+ * flag before sending out.
+ */
+static void send_command_raw(unsigned int cmd, unsigned int arg)
+{
+	unsigned int status;
+	uintptr_t reg_base = rpi3_sdhost_params.reg_base;
+
+	/* wait for previous command finish */
+	rpi3_sdhost_waitcommand();
+
+	/* clean error status */
+	status = mmio_read_32(reg_base + HC_HOSTSTATUS);
+	if (status & HC_HSTST_MASK_ERROR_ALL)
+		mmio_write_32(reg_base + HC_HOSTSTATUS, status);
+
+	/* recording the command */
+	rpi3_sdhost_params.current_cmd = cmd & HC_CMD_COMMAND_MASK;
+
+	/* send the argument and command */
+	mmio_write_32(reg_base + HC_ARGUMENT, arg);
+	mmio_write_32(reg_base + HC_COMMAND, cmd | HC_CMD_ENABLE);
+}
+
+/**
+ * Send the command and argument to the SDHOST, decorated with control
+ * flags.
+ *
+ * This function will use send_command_raw to send the commands to SDHOST.
+ * But before sending it will decorate the command with control flags specific
+ * to SDHOST.
+ */
+static void send_command_decorated(unsigned int cmd, unsigned int arg)
+{
+	unsigned int cmd_flags = 0;
+
+	switch (cmd & HC_CMD_COMMAND_MASK) {
+	case MMC_CMD(0):
+		cmd_flags |= HC_CMD_RESPONSE_NONE;
+		break;
+	case MMC_ACMD(51):
+		cmd_flags |= HC_CMD_READ;
+		break;
+	case MMC_CMD(8):
+	case MMC_CMD(11):
+	case MMC_CMD(17):
+	case MMC_CMD(18):
+		cmd_flags |= HC_CMD_READ;
+		break;
+	case MMC_CMD(20):
+	case MMC_CMD(24):
+	case MMC_CMD(25):
+		cmd_flags |= HC_CMD_WRITE;
+		break;
+	case MMC_CMD(12):
+		cmd_flags |= HC_CMD_BUSY;
+		break;
+	default:
+		break;
+	}
+	send_command_raw(cmd | cmd_flags, arg);
+}
+
+/**
+ * drains the FIFO on DATA port
+ *
+ * This function drains any data left in the DATA port.
+ */
+static void rpi3_drain_fifo(void)
+{
+	uintptr_t reg_base = rpi3_sdhost_params.reg_base;
+	volatile int timeout = 100000;
+
+	rpi3_sdhost_waitcommand();
+
+	while (mmio_read_32(reg_base + HC_HOSTSTATUS) & HC_HSTST_HAVEDATA) {
+		mmio_read_32(reg_base + HC_DATAPORT);
+		udelay(100);
+	}
+
+	while (1) {
+		uint32_t edm, fsm;
+
+		edm = mmio_read_32(reg_base + HC_DEBUG);
+		fsm = edm & HC_DBG_FSM_MASK;
+
+		if ((fsm == HC_DBG_FSM_IDENTMODE) ||
+		    (fsm == HC_DBG_FSM_DATAMODE))
+			break;
+
+		if ((fsm == HC_DBG_FSM_READWAIT) ||
+		    (fsm == HC_DBG_FSM_WRITESTART1) ||
+		    (fsm == HC_DBG_FSM_READDATA)) {
+			mmio_write_32(reg_base + HC_DEBUG,
+				      edm | HC_DBG_FORCE_DATA_MODE);
+			break;
+		}
+
+		if (--timeout <= 0) {
+			ERROR("rpi3_sdhost: %s cannot recover stat\n",
+			      __func__);
+			return;
+		}
+	}
+}
+
+/**
+ * Dump SDHOST registers
+ */
+static void rpi3_sdhost_print_regs(void)
+{
+	uintptr_t reg_base = rpi3_sdhost_params.reg_base;
+
+	INFO("rpi3_sdhost: HC_COMMAND:        0x%08x\n",
+	     mmio_read_32(reg_base + HC_COMMAND));
+	INFO("rpi3_sdhost: HC_ARGUMENT:       0x%08x\n",
+	     mmio_read_32(reg_base + HC_ARGUMENT));
+	INFO("rpi3_sdhost: HC_TIMEOUTCOUNTER: 0x%08x\n",
+	     mmio_read_32(reg_base + HC_TIMEOUTCOUNTER));
+	INFO("rpi3_sdhost: HC_CLOCKDIVISOR:   0x%08x\n",
+	     mmio_read_32(reg_base + HC_CLOCKDIVISOR));
+	INFO("rpi3_sdhost: HC_RESPONSE_0:     0x%08x\n",
+	     mmio_read_32(reg_base + HC_RESPONSE_0));
+	INFO("rpi3_sdhost: HC_RESPONSE_1:     0x%08x\n",
+	     mmio_read_32(reg_base + HC_RESPONSE_1));
+	INFO("rpi3_sdhost: HC_RESPONSE_2:     0x%08x\n",
+	     mmio_read_32(reg_base + HC_RESPONSE_2));
+	INFO("rpi3_sdhost: HC_RESPONSE_3:     0x%08x\n",
+	     mmio_read_32(reg_base + HC_RESPONSE_3));
+	INFO("rpi3_sdhost: HC_HOSTSTATUS:     0x%08x\n",
+	     mmio_read_32(reg_base + HC_HOSTSTATUS));
+	INFO("rpi3_sdhost: HC_POWER:          0x%08x\n",
+	     mmio_read_32(reg_base + HC_POWER));
+	INFO("rpi3_sdhost: HC_DEBUG:          0x%08x\n",
+	     mmio_read_32(reg_base + HC_DEBUG));
+	INFO("rpi3_sdhost: HC_HOSTCONFIG:     0x%08x\n",
+	     mmio_read_32(reg_base + HC_HOSTCONFIG));
+	INFO("rpi3_sdhost: HC_BLOCKSIZE:      0x%08x\n",
+	     mmio_read_32(reg_base + HC_BLOCKSIZE));
+	INFO("rpi3_sdhost: HC_BLOCKCOUNT:     0x%08x\n",
+	     mmio_read_32(reg_base + HC_BLOCKCOUNT));
+}
+
+/**
+ * Reset SDHOST
+ */
+static void rpi3_sdhost_reset(void)
+{
+	uintptr_t reg_base = rpi3_sdhost_params.reg_base;
+	unsigned int dbg;
+	uint32_t tmp1;
+
+	mmio_write_32(reg_base + HC_POWER, 0);
+	mmio_write_32(reg_base + HC_COMMAND, 0);
+	mmio_write_32(reg_base + HC_ARGUMENT, 0);
+
+	mmio_write_32(reg_base + HC_TIMEOUTCOUNTER, HC_TIMEOUT_DEFAULT);
+	mmio_write_32(reg_base + HC_CLOCKDIVISOR, 0);
+	mmio_write_32(reg_base + HC_HOSTSTATUS, HC_HSTST_RESET);
+	mmio_write_32(reg_base + HC_HOSTCONFIG, 0);
+	mmio_write_32(reg_base + HC_BLOCKSIZE, 0);
+	mmio_write_32(reg_base + HC_BLOCKCOUNT, 0);
+
+	dbg = mmio_read_32(reg_base + HC_DEBUG);
+	dbg &= ~((HC_DBG_FIFO_THRESH_MASK << HC_DBG_FIFO_THRESH_READ_SHIFT) |
+		 (HC_DBG_FIFO_THRESH_MASK << HC_DBG_FIFO_THRESH_WRITE_SHIFT));
+	dbg |= (HC_FIFO_THRESH_READ << HC_DBG_FIFO_THRESH_READ_SHIFT) |
+		(HC_FIFO_THRESH_WRITE << HC_DBG_FIFO_THRESH_WRITE_SHIFT);
+	mmio_write_32(reg_base + HC_DEBUG, dbg);
+	mdelay(250);
+	mmio_write_32(reg_base + HC_POWER, 1);
+	mdelay(250);
+	rpi3_sdhost_params.clk_rate = 0;
+
+	mmio_write_32(reg_base + HC_CLOCKDIVISOR, HC_CLOCKDIVISOR_MAXVAL);
+	tmp1 = mmio_read_32(reg_base + HC_HOSTCONFIG);
+	mmio_write_32(reg_base + HC_HOSTCONFIG, tmp1 | HC_HSTCF_INT_BUSY);
+}
+
+static void rpi3_sdhost_initialize(void)
+{
+	uintptr_t reg_base = rpi3_sdhost_params.reg_base;
+
+	assert((rpi3_sdhost_params.reg_base & MMC_BLOCK_MASK) == 0);
+
+	rpi3_sdhost_reset();
+
+	mmio_write_32(reg_base + HC_CLOCKDIVISOR, HC_CLOCKDIVISOR_PREFERVAL);
+	udelay(300);
+}
+
+static int rpi3_sdhost_send_cmd(struct mmc_cmd *cmd)
+{
+	uintptr_t reg_base = rpi3_sdhost_params.reg_base;
+	int err = 0;
+	uint32_t cmd_idx;
+	uint32_t cmd_arg;
+	uint32_t cmd_flags = 0;
+	uint32_t intmask;
+
+	/* Wait for the command done */
+	err = rpi3_sdhost_waitcommand();
+	if (err != 0) {
+		WARN("previous command not done yet\n");
+		return err;
+	}
+
+	cmd_idx = cmd->cmd_idx & HC_CMD_COMMAND_MASK;
+	if (cmd_idx == MMC_CMD(17))
+		cmd_idx = MMC_CMD(18);
+
+	cmd_arg = cmd->cmd_arg;
+	if (cmd_idx == MMC_ACMD(51)) {
+		/* if previous cmd send to SDHOST is not MMC_CMD(55).
+		 * It means this MMC_ACMD(51) is a resend.
+		 * And we must also resend MMC_CMD(55) in this case
+		 */
+		if (rpi3_sdhost_params.current_cmd != MMC_CMD(55)) {
+			send_command_decorated(
+				MMC_CMD(55),
+				rpi3_sdhost_params.sdcard_rca <<
+				RCA_SHIFT_OFFSET);
+			rpi3_sdhost_params.mmc_app_cmd = 1;
+			rpi3_sdhost_waitcommand();
+
+			/* Also we need to call prepare to clean the buffer */
+			rpi3_sdhost_prepare(0, (uintptr_t)NULL, 8);
+		}
+	}
+
+	/* We ignore MMC_CMD(12) sending from the TF-A's MMC driver
+	 * because we send MMC_CMD(12) by ourselves.
+	 */
+	if (cmd_idx == MMC_CMD(12))
+		return 0;
+
+	if ((cmd->resp_type & MMC_RSP_136) &&
+	    (cmd->resp_type & MMC_RSP_BUSY)) {
+		ERROR("rpi3_sdhost: unsupported response type!\n");
+		return -(EOPNOTSUPP);
+	}
+
+	if (cmd->resp_type & MMC_RSP_48 && cmd->resp_type != MMC_RESPONSE_R2) {
+		/* 48-bit command
+		 * We don't need to set any flags here because it is default.
+		 */
+	} else if (cmd->resp_type & MMC_RSP_136) {
+		/* 136-bit command */
+		cmd_flags |= HC_CMD_RESPONSE_LONG;
+	} else {
+		/* no respond command */
+		cmd_flags |= HC_CMD_RESPONSE_NONE;
+	}
+
+	rpi3_sdhost_params.cmdbusy = 0;
+	if (cmd->resp_type & MMC_RSP_BUSY) {
+		cmd_flags |= HC_CMD_BUSY;
+		rpi3_sdhost_params.cmdbusy = 1;
+	}
+
+	if (rpi3_sdhost_params.mmc_app_cmd) {
+		switch (cmd_idx) {
+		case MMC_ACMD(41):
+			if (cmd_arg == OCR_HCS)
+				cmd_arg |= OCR_3_3_3_4;
+			break;
+		default:
+			break;
+		}
+		rpi3_sdhost_params.mmc_app_cmd = 0;
+	}
+
+	if (cmd_idx == MMC_CMD(55))
+		rpi3_sdhost_params.mmc_app_cmd = 1;
+
+	send_command_decorated(cmd_idx | cmd_flags, cmd_arg);
+
+	intmask = mmio_read_32(reg_base + HC_HOSTSTATUS);
+	if (rpi3_sdhost_params.cmdbusy && (intmask & HC_HSTST_INT_BUSY)) {
+		mmio_write_32(reg_base + HC_HOSTSTATUS, HC_HSTST_INT_BUSY);
+		rpi3_sdhost_params.cmdbusy = 0;
+	}
+
+	if (!(cmd_flags & HC_CMD_RESPONSE_NONE)) {
+		err = rpi3_sdhost_waitcommand();
+		if (err != 0)
+			ERROR("rpi3_sdhost: cmd cannot be finished\n");
+	}
+
+	cmd->resp_data[0] = mmio_read_32(reg_base + HC_RESPONSE_0);
+	cmd->resp_data[1] = mmio_read_32(reg_base + HC_RESPONSE_1);
+	cmd->resp_data[2] = mmio_read_32(reg_base + HC_RESPONSE_2);
+	cmd->resp_data[3] = mmio_read_32(reg_base + HC_RESPONSE_3);
+
+	if (mmio_read_32(reg_base + HC_COMMAND) & HC_CMD_FAILED) {
+		uint32_t sdhsts = mmio_read_32(reg_base + HC_HOSTSTATUS);
+
+		mmio_write_32(reg_base + HC_HOSTSTATUS,
+			      HC_HSTST_MASK_ERROR_ALL);
+
+		if (!(sdhsts & HC_HSTST_ERROR_CRC7)
+		    || (cmd_idx != MMC_ACMD(51))) {
+			if (sdhsts & HC_HSTST_TIMEOUT_CMD) {
+				ERROR("rpi3_sdhost: timeout status 0x%x\n",
+				      sdhsts);
+				err = -(ETIMEDOUT);
+			} else {
+				ERROR("rpi3_sdhost: unknown err, cmd = 0x%x\n",
+				      mmio_read_32(reg_base + HC_COMMAND));
+				ERROR("rpi3_sdhost status: 0x%x\n", sdhsts);
+				err = -(EILSEQ);
+			}
+		}
+	}
+
+	if ((!err) && (cmd_idx == MMC_CMD(3))) {
+		/* we keep the RCA in case to send MMC_CMD(55) ourselves */
+		rpi3_sdhost_params.sdcard_rca = (cmd->resp_data[0]
+						 & 0xFFFF0000U) >> 16;
+	}
+
+	return err;
+}
+
+static int rpi3_sdhost_set_clock(unsigned int clk)
+{
+	uintptr_t reg_base = rpi3_sdhost_params.reg_base;
+	uint32_t max_clk = 250000000;
+	uint32_t div;
+
+	if (clk < 100000) {
+		mmio_write_32(reg_base + HC_CLOCKDIVISOR,
+			      HC_CLOCKDIVISOR_MAXVAL);
+		return 0;
+	}
+
+	div = max_clk / clk;
+	if (div < 2)
+		div = 2;
+
+	if ((max_clk / div) > clk)
+		div++;
+
+	div -= 2;
+	if (div > HC_CLOCKDIVISOR_MAXVAL)
+		div = HC_CLOCKDIVISOR_MAXVAL;
+
+	rpi3_sdhost_params.clk_rate = max_clk / (div + 2);
+	rpi3_sdhost_params.ns_per_fifo_word = (1000000000 /
+					       rpi3_sdhost_params.clk_rate)
+		* 8;
+
+	mmio_write_32(reg_base + HC_CLOCKDIVISOR, div);
+	return 0;
+}
+
+static int rpi3_sdhost_set_ios(unsigned int clk, unsigned int width)
+{
+	uintptr_t reg_base = rpi3_sdhost_params.reg_base;
+	uint32_t tmp1;
+
+	rpi3_sdhost_set_clock(clk);
+	VERBOSE("rpi3_sdhost: Changing clock to %dHz for data mode\n", clk);
+
+	if (width != MMC_BUS_WIDTH_4 && width != MMC_BUS_WIDTH_1) {
+		ERROR("rpi3_sdhost: width %d not supported\n", width);
+		return -(EOPNOTSUPP);
+	}
+	rpi3_sdhost_params.bus_width = width;
+
+	tmp1 = mmio_read_32(reg_base + HC_HOSTCONFIG);
+	tmp1 &= ~(HC_HSTCF_EXTBUS_4BIT);
+	if (rpi3_sdhost_params.bus_width == MMC_BUS_WIDTH_4)
+		tmp1 |= HC_HSTCF_EXTBUS_4BIT;
+
+	mmio_write_32(reg_base + HC_HOSTCONFIG, tmp1);
+	tmp1 = mmio_read_32(reg_base + HC_HOSTCONFIG);
+	mmio_write_32(reg_base + HC_HOSTCONFIG, tmp1 |
+		      HC_HSTCF_SLOW_CARD | HC_HSTCF_INTBUS_WIDE);
+
+	return 0;
+}
+
+static int rpi3_sdhost_prepare(int lba, uintptr_t buf, size_t size)
+{
+	uintptr_t reg_base = rpi3_sdhost_params.reg_base;
+	size_t blocks;
+	size_t blocksize;
+
+	if (size < 512) {
+		blocksize = size;
+		blocks = 1;
+	} else {
+		blocksize = 512;
+		blocks = size / blocksize;
+		if (size % blocksize != 0)
+			blocks++;
+	}
+
+	rpi3_drain_fifo();
+
+	mmio_write_32(reg_base + HC_BLOCKSIZE, blocksize);
+	mmio_write_32(reg_base + HC_BLOCKCOUNT, blocks);
+	udelay(100);
+	return 0;
+}
+
+static int rpi3_sdhost_read(int lba, uintptr_t buf, size_t size)
+{
+	int err = 0;
+	uint32_t *buf1 = ((uint32_t *) buf);
+	uintptr_t reg_base = rpi3_sdhost_params.reg_base;
+	int timeout = 100000;
+	int remaining_words = 0;
+
+	for (int i = 0; i < size / 4; i++) {
+		volatile int t = timeout;
+		uint32_t hsts_err;
+
+		while ((mmio_read_32(reg_base + HC_HOSTSTATUS)
+			& HC_HSTST_HAVEDATA) == 0) {
+			if (t == 0) {
+				ERROR("rpi3_sdhost: fifo timeout after %dus\n",
+				      timeout);
+				err = -(ETIMEDOUT);
+				break;
+			}
+			t--;
+			udelay(10);
+		}
+		if (t == 0)
+			break;
+
+		uint32_t data = mmio_read_32(reg_base + HC_DATAPORT);
+
+		hsts_err = mmio_read_32(reg_base + HC_HOSTSTATUS)
+			& HC_HSTST_MASK_ERROR_ALL;
+		if (hsts_err) {
+			ERROR("rpi3_sdhost: transfer FIFO word %d: 0x%x\n",
+			      i,
+			      mmio_read_32(reg_base + HC_HOSTSTATUS));
+			rpi3_sdhost_print_regs();
+
+			err = -(EILSEQ);
+
+			/* clean the error status */
+			mmio_write_32(reg_base + HC_HOSTSTATUS, hsts_err);
+		}
+
+		if (buf1)
+			buf1[i] = data;
+
+		/* speeding up if the remaining words are still a lot */
+		remaining_words = (mmio_read_32(reg_base + HC_DEBUG) >> 4)
+			& HC_DBG_FIFO_THRESH_MASK;
+		if (remaining_words >= 7)
+			continue;
+
+		/* delay. slowing down the read process */
+		udelay(100);
+	}
+
+	/* We decide to stop by ourselves.
+	 * It is because MMC_CMD(18) -> MMC_CMD(13) -> MMC_CMD(12)
+	 * doesn't work for RPi3 SDHost.
+	 */
+	if (rpi3_sdhost_params.current_cmd == MMC_CMD(18))
+		send_command_decorated(MMC_CMD(12), 0);
+
+	if (err == -(EILSEQ)) {
+		const int max_retries = 20;
+		int r;
+
+		rpi3_sdhost_params.crc_err_retries++;
+		if (rpi3_sdhost_params.crc_err_retries < max_retries) {
+			/* retries if there's an CRC error */
+			r = rpi3_sdhost_prepare(lba, buf, size);
+			send_command_decorated(MMC_CMD(18), lba);
+			r = rpi3_sdhost_read(lba, buf, size);
+			if (r == 0)
+				err = 0;
+		}
+	}
+
+	return err;
+}
+
+static int rpi3_sdhost_write(int lba, uintptr_t buf, size_t size)
+{
+	uint32_t *buf1 = ((uint32_t *) buf);
+	uintptr_t reg_base = rpi3_sdhost_params.reg_base;
+	int err = 0;
+	int remaining_words = 0;
+
+	for (int i = 0; i < size / 4; i++) {
+		uint32_t hsts_err;
+		uint32_t data = buf1[i];
+		uint32_t dbg;
+		uint32_t fsm_state;
+
+		mmio_write_32(reg_base + HC_DATAPORT, data);
+
+		dbg = mmio_read_32(reg_base + HC_DEBUG);
+		fsm_state = dbg & HC_DBG_FSM_MASK;
+		if (fsm_state != HC_DBG_FSM_WRITEDATA
+		    && fsm_state != HC_DBG_FSM_WRITESTART1
+		    && fsm_state != HC_DBG_FSM_WRITESTART2
+		    && fsm_state != HC_DBG_FSM_WRITECRC
+		    && fsm_state != HC_DBG_FSM_WRITEWAIT1
+		    && fsm_state != HC_DBG_FSM_WRITEWAIT2) {
+			hsts_err = mmio_read_32(reg_base + HC_HOSTSTATUS)
+				& HC_HSTST_MASK_ERROR_ALL;
+			if (hsts_err)
+				err = -(EILSEQ);
+		}
+
+		/* speeding up if the remaining words are not many */
+		remaining_words = (mmio_read_32(reg_base + HC_DEBUG) >> 4)
+			& HC_DBG_FIFO_THRESH_MASK;
+		if (remaining_words <= 4)
+			continue;
+
+		udelay(100);
+	}
+
+	/* We decide to stop by ourselves.
+	 * It is because MMC_CMD(25) -> MMC_CMD(13) -> MMC_CMD(12)
+	 * doesn't work for RPi3 SDHost.
+	 */
+	if (rpi3_sdhost_params.current_cmd == MMC_CMD(25))
+		send_command_decorated(MMC_CMD(12), 0);
+
+	return err;
+}
+
+void rpi3_sdhost_init(struct rpi3_sdhost_params *params,
+		    struct mmc_device_info *mmc_dev_info)
+{
+	assert((params != 0) &&
+	       ((params->reg_base & MMC_BLOCK_MASK) == 0));
+
+	memcpy(&rpi3_sdhost_params, params, sizeof(struct rpi3_sdhost_params));
+
+	/* backup GPIO 48 to 53 configurations */
+	for (int i = 48; i <= 53; i++) {
+		rpi3_sdhost_params.gpio48_pinselect[i - 48]
+			= rpi3_gpio_get_select(i);
+		VERBOSE("rpi3_sdhost: Original GPIO state %d: %d\n",
+			i,
+			rpi3_sdhost_params.gpio48_pinselect[i - 48]);
+	}
+
+	/* setting pull resistors for 48 to 53.
+	 * GPIO 48 (SD_CLK) to GPIO_PULL_UP
+	 * GPIO 49 (SD_CMD) to GPIO_PULL_NONE
+	 * GPIO 50 (SD_D0)  to GPIO_PULL_NONE
+	 * GPIO 51 (SD_D1)  to GPIO_PULL_NONE
+	 * GPIO 52 (SD_D2)  to GPIO_PULL_NONE
+	 * GPIO 53 (SD_D3)  to GPIO_PULL_NONE
+	 */
+	gpio_set_pull(48, GPIO_PULL_UP);
+	for (int i = 49; i <= 53; i++)
+		gpio_set_pull(i, GPIO_PULL_NONE);
+
+	/* Set pin 48-53 to alt-0. It means route SDHOST to card slot */
+	for (int i = 48; i <= 53; i++)
+		rpi3_gpio_set_select(i, RPI3_GPIO_FUNC_ALT0);
+
+	mmc_init(&rpi3_sdhost_ops, params->clk_rate, params->bus_width,
+		 params->flags, mmc_dev_info);
+}
+
+void rpi3_sdhost_stop(void)
+{
+	uintptr_t reg_base = rpi3_sdhost_params.reg_base;
+
+	VERBOSE("rpi3_sdhost: Shutting down: drain FIFO out\n");
+	rpi3_drain_fifo();
+
+	VERBOSE("rpi3_sdhost: Shutting down: slowing down the clock\n");
+	mmio_write_32(reg_base+HC_CLOCKDIVISOR, HC_CLOCKDIVISOR_SLOWVAL);
+	udelay(500);
+
+	VERBOSE("rpi3_sdhost: Shutting down: put SDHost into idle state\n");
+	send_command_decorated(MMC_CMD(0), 0);
+	udelay(500);
+
+	mmio_write_32(reg_base + HC_COMMAND, 0);
+	mmio_write_32(reg_base + HC_ARGUMENT, 0);
+	mmio_write_32(reg_base + HC_TIMEOUTCOUNTER, HC_TIMEOUT_IDLE);
+	mmio_write_32(reg_base + HC_CLOCKDIVISOR, HC_CLOCKDIVISOR_STOPVAL);
+
+	udelay(100);
+
+	mmio_write_32(reg_base + HC_POWER, 0);
+	mmio_write_32(reg_base + HC_HOSTCONFIG, 0);
+	mmio_write_32(reg_base + HC_BLOCKSIZE, 0x400);
+	mmio_write_32(reg_base + HC_BLOCKCOUNT, 0);
+	mmio_write_32(reg_base + HC_HOSTSTATUS, 0x7f8);
+
+	mmio_write_32(reg_base + HC_COMMAND, 0);
+	mmio_write_32(reg_base + HC_ARGUMENT, 0);
+
+	udelay(100);
+
+	/* Restore the pinmux to original state */
+	for (int i = 48; i <= 53; i++) {
+		rpi3_gpio_set_select(i,
+				     rpi3_sdhost_params.gpio48_pinselect[i-48]);
+	}
+
+	/* Must reset the pull resistors for u-boot to work.
+	 * GPIO 48 (SD_CLK) to GPIO_PULL_NONE
+	 * GPIO 49 (SD_CMD) to GPIO_PULL_UP
+	 * GPIO 50 (SD_D0)  to GPIO_PULL_UP
+	 * GPIO 51 (SD_D1)  to GPIO_PULL_UP
+	 * GPIO 52 (SD_D2)  to GPIO_PULL_UP
+	 * GPIO 53 (SD_D3)  to GPIO_PULL_UP
+	 */
+	gpio_set_pull(48, GPIO_PULL_NONE);
+	for (int i = 49; i <= 53; i++)
+		gpio_set_pull(i, GPIO_PULL_UP);
+}

include/drivers/rpi3/sdhost/rpi3_sdhost.h

+/*
+ * Copyright (c) 2019, Linaro Limited
+ * Copyright (c) 2019, Ying-Chun Liu (PaulLiu) <paul.liu@linaro.org>
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#ifndef RPI3_SDHOST_H
+#define	RPI3_SDHOST_H
+
+#include <drivers/mmc.h>
+#include <stdint.h>
+#include <platform_def.h>
+
+struct rpi3_sdhost_params {
+	uintptr_t	reg_base;
+	uint32_t	clk_rate;
+	uint32_t	bus_width;
+	uint32_t        flags;
+	uint32_t	current_cmd;
+	uint8_t		cmdbusy;
+	uint8_t		mmc_app_cmd;
+	uint32_t	ns_per_fifo_word;
+	uint32_t	crc_err_retries;
+
+	uint32_t	sdcard_rca;
+	uint32_t	gpio48_pinselect[6];
+};
+
+void rpi3_sdhost_init(struct rpi3_sdhost_params *params,
+		      struct mmc_device_info *mmc_dev_info);
+void rpi3_sdhost_stop(void);
+
+/* Registers */
+#define HC_COMMAND			0x00        /* Command and flags */
+#define HC_ARGUMENT			0x04
+#define HC_TIMEOUTCOUNTER		0x08
+#define HC_CLOCKDIVISOR			0x0c
+#define HC_RESPONSE_0			0x10
+#define HC_RESPONSE_1			0x14
+#define HC_RESPONSE_2			0x18
+#define HC_RESPONSE_3			0x1c
+#define HC_HOSTSTATUS			0x20
+#define HC_POWER			0x30
+#define HC_DEBUG			0x34
+#define HC_HOSTCONFIG			0x38
+#define HC_BLOCKSIZE			0x3c
+#define HC_DATAPORT			0x40
+#define HC_BLOCKCOUNT			0x50
+
+/* Flags for HC_COMMAND register */
+#define HC_CMD_ENABLE			0x8000
+#define HC_CMD_FAILED			0x4000
+#define HC_CMD_BUSY			0x0800
+#define HC_CMD_RESPONSE_NONE		0x0400
+#define HC_CMD_RESPONSE_LONG		0x0200
+#define HC_CMD_WRITE			0x0080
+#define HC_CMD_READ			0x0040
+#define HC_CMD_COMMAND_MASK		0x003f
+
+#define HC_CLOCKDIVISOR_MAXVAL		0x07ff
+#define HC_CLOCKDIVISOR_PREFERVAL	0x027b
+#define HC_CLOCKDIVISOR_SLOWVAL		0x0148
+#define HC_CLOCKDIVISOR_STOPVAL		0x01fb
+
+/* Flags for HC_HOSTSTATUS register */
+#define HC_HSTST_HAVEDATA		0x0001
+#define HC_HSTST_ERROR_FIFO		0x0008
+#define HC_HSTST_ERROR_CRC7		0x0010
+#define HC_HSTST_ERROR_CRC16		0x0020
+#define HC_HSTST_TIMEOUT_CMD		0x0040
+#define HC_HSTST_TIMEOUT_DATA		0x0080
+#define HC_HSTST_INT_BLOCK		0x0200
+#define HC_HSTST_INT_BUSY		0x0400
+
+#define HC_HSTST_RESET			0xffff
+
+#define HC_HSTST_MASK_ERROR_DATA	(HC_HSTST_ERROR_FIFO | \
+					 HC_HSTST_ERROR_CRC7 | \
+					 HC_HSTST_ERROR_CRC16 | \
+					 HC_HSTST_TIMEOUT_DATA)
+
+#define HC_HSTST_MASK_ERROR_ALL		(HC_HSTST_MASK_ERROR_DATA | \
+					 HC_HSTST_TIMEOUT_CMD)
+
+/* Flags for HC_HOSTCONFIG register */
+#define HC_HSTCF_INTBUS_WIDE		0x0002
+#define HC_HSTCF_EXTBUS_4BIT		0x0004
+#define HC_HSTCF_SLOW_CARD		0x0008
+#define HC_HSTCF_INT_DATA		0x0010
+#define HC_HSTCF_INT_BLOCK		0x0100
+#define HC_HSTCF_INT_BUSY		0x0400
+
+/* Flags for HC_DEBUG register */
+#define HC_DBG_FIFO_THRESH_WRITE_SHIFT	9
+#define HC_DBG_FIFO_THRESH_READ_SHIFT	14
+#define HC_DBG_FIFO_THRESH_MASK		0x001f
+#define HC_DBG_FSM_MASK			0xf
+#define HC_DBG_FSM_IDENTMODE		0x0
+#define HC_DBG_FSM_DATAMODE		0x1
+#define HC_DBG_FSM_READDATA		0x2
+#define HC_DBG_FSM_WRITEDATA		0x3
+#define HC_DBG_FSM_READWAIT		0x4
+#define HC_DBG_FSM_READCRC		0x5
+#define HC_DBG_FSM_WRITECRC		0x6
+#define HC_DBG_FSM_WRITEWAIT1		0x7
+#define HC_DBG_FSM_POWERDOWN		0x8
+#define HC_DBG_FSM_POWERUP		0x9
+#define HC_DBG_FSM_WRITESTART1		0xa
+#define HC_DBG_FSM_WRITESTART2		0xb
+#define HC_DBG_FSM_GENPULSES		0xc
+#define HC_DBG_FSM_WRITEWAIT2		0xd
+#define HC_DBG_FSM_STARTPOWDOWN		0xf
+#define HC_DBG_FORCE_DATA_MODE		0x40000
+
+/* Settings */
+#define HC_FIFO_SIZE			16
+#define HC_FIFO_THRESH_READ		4
+#define HC_FIFO_THRESH_WRITE		4
+
+#define HC_TIMEOUT_DEFAULT		0x00f00000
+#define HC_TIMEOUT_IDLE			0x00a00000
+
+#endif  /* RPI3_SDHOST_H */