mmc: add new Alcor Micro Cardreader SD/MMC driver

This driver provides support for Alcor Micro AU6601 and AU6621
SD/MMC controller.

Signed-off-by: Oleksij Rempel <linux@rempel-privat.de>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

3 files changed, 1173 insertions, 0 deletions

diff --git a/drivers/mmc/host/Kconfig b/drivers/mmc/host/Kconfig
index 720311ece714..5fa580cec831 100644
--- a/drivers/mmc/host/Kconfig
+++ b/drivers/mmc/host/Kconfig
@@ -441,6 +441,13 @@ config MMC_WBSD
 
 	  If unsure, say N.
 
+config MMC_ALCOR
+	tristate "Alcor Micro/Alcor Link SD/MMC controller"
+	depends on MISC_ALCOR_PCI
+	help
+	  Say Y here to include driver code to support SD/MMC card interface
+	  of Alcor Micro PCI-E card reader
+
 config MMC_AU1X
 	tristate "Alchemy AU1XX0 MMC Card Interface support"
 	depends on MIPS_ALCHEMY
diff --git a/drivers/mmc/host/Makefile b/drivers/mmc/host/Makefile
index 720d37777098..0a38e654a2ce 100644
--- a/drivers/mmc/host/Makefile
+++ b/drivers/mmc/host/Makefile
@@ -24,6 +24,7 @@ obj-$(CONFIG_MMC_SDHCI_F_SDH30)	+= sdhci_f_sdh30.o
 obj-$(CONFIG_MMC_SDHCI_SPEAR)	+= sdhci-spear.o
 obj-$(CONFIG_MMC_WBSD)		+= wbsd.o
 obj-$(CONFIG_MMC_AU1X)		+= au1xmmc.o
+obj-$(CONFIG_MMC_ALCOR)	+= alcor.o
 obj-$(CONFIG_MMC_MTK)		+= mtk-sd.o
 obj-$(CONFIG_MMC_OMAP)		+= omap.o
 obj-$(CONFIG_MMC_OMAP_HS)	+= omap_hsmmc.o
diff --git a/drivers/mmc/host/alcor.c b/drivers/mmc/host/alcor.c
new file mode 100644
index 000000000000..f729a649d7c0
--- /dev/null
+++ b/drivers/mmc/host/alcor.c
@@ -0,0 +1,1165 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2018 Oleksij Rempel <linux@rempel-privat.de>
+ *
+ * Driver for Alcor Micro AU6601 and AU6621 controllers
+ */
+
+/* Note: this driver was created without any documentation. Based
+ * on sniffing, testing and in some cases mimic of original driver.
+ * As soon as some one with documentation or more experience in SD/MMC, or
+ * reverse engineering then me, please review this driver and question every
+ * thing what I did. 2018 Oleksij Rempel <linux@rempel-privat.de>
+ */
+
+#include <linux/delay.h>
+#include <linux/pci.h>
+#include <linux/module.h>
+#include <linux/io.h>
+#include <linux/pm.h>
+#include <linux/irq.h>
+#include <linux/interrupt.h>
+#include <linux/platform_device.h>
+
+#include <linux/mmc/host.h>
+#include <linux/mmc/mmc.h>
+
+#include <linux/alcor_pci.h>
+
+enum alcor_cookie {
+	COOKIE_UNMAPPED,
+	COOKIE_PRE_MAPPED,
+	COOKIE_MAPPED,
+};
+
+struct alcor_pll_conf {
+	unsigned int clk_src_freq;
+	unsigned int clk_src_reg;
+	unsigned int min_div;
+	unsigned int max_div;
+};
+
+struct alcor_sdmmc_host {
+	struct  device *dev;
+	struct alcor_pci_priv *alcor_pci;
+
+	struct mmc_host *mmc;
+	struct mmc_request *mrq;
+	struct mmc_command *cmd;
+	struct mmc_data *data;
+	unsigned int dma_on:1;
+	unsigned int early_data:1;
+
+	struct mutex cmd_mutex;
+
+	struct delayed_work timeout_work;
+
+	struct sg_mapping_iter sg_miter;	/* SG state for PIO */
+	struct scatterlist *sg;
+	unsigned int blocks;		/* remaining PIO blocks */
+	int sg_count;
+
+	u32			irq_status_sd;
+	unsigned char		cur_power_mode;
+};
+
+static const struct alcor_pll_conf alcor_pll_cfg[] = {
+	/* MHZ,		CLK src,		max div, min div */
+	{ 31250000,	AU6601_CLK_31_25_MHZ,	1,	511},
+	{ 48000000,	AU6601_CLK_48_MHZ,	1,	511},
+	{125000000,	AU6601_CLK_125_MHZ,	1,	511},
+	{384000000,	AU6601_CLK_384_MHZ,	1,	511},
+};
+
+static inline void alcor_rmw8(struct alcor_sdmmc_host *host, unsigned int addr,
+			       u8 clear, u8 set)
+{
+	struct alcor_pci_priv *priv = host->alcor_pci;
+	u32 var;
+
+	var = alcor_read8(priv, addr);
+	var &= ~clear;
+	var |= set;
+	alcor_write8(priv, var, addr);
+}
+
+/* As soon as irqs are masked, some status updates may be missed.
+ * Use this with care.
+ */
+static inline void alcor_mask_sd_irqs(struct alcor_sdmmc_host *host)
+{
+	struct alcor_pci_priv *priv = host->alcor_pci;
+
+	alcor_write32(priv, 0, AU6601_REG_INT_ENABLE);
+}
+
+static inline void alcor_unmask_sd_irqs(struct alcor_sdmmc_host *host)
+{
+	struct alcor_pci_priv *priv = host->alcor_pci;
+
+	alcor_write32(priv, AU6601_INT_CMD_MASK | AU6601_INT_DATA_MASK |
+		  AU6601_INT_CARD_INSERT | AU6601_INT_CARD_REMOVE |
+		  AU6601_INT_OVER_CURRENT_ERR,
+		  AU6601_REG_INT_ENABLE);
+}
+
+static void alcor_reset(struct alcor_sdmmc_host *host, u8 val)
+{
+	struct alcor_pci_priv *priv = host->alcor_pci;
+	int i;
+
+	alcor_write8(priv, val | AU6601_BUF_CTRL_RESET,
+		      AU6601_REG_SW_RESET);
+	for (i = 0; i < 100; i++) {
+		if (!(alcor_read8(priv, AU6601_REG_SW_RESET) & val))
+			return;
+		udelay(50);
+	}
+	dev_err(host->dev, "%s: timeout\n", __func__);
+}
+
+static void alcor_data_set_dma(struct alcor_sdmmc_host *host)
+{
+	struct alcor_pci_priv *priv = host->alcor_pci;
+	u32 addr, len;
+
+	if (!host->sg_count)
+		return;
+
+	if (!host->sg) {
+		dev_err(host->dev, "have blocks, but no SG\n");
+		return;
+	}
+
+	if (!sg_dma_len(host->sg)) {
+		dev_err(host->dev, "DMA SG len == 0\n");
+		return;
+	}
+
+
+	addr = (u32)sg_dma_address(host->sg);
+	len = sg_dma_len(host->sg);
+
+	alcor_write32(priv, addr, AU6601_REG_SDMA_ADDR);
+	host->sg = sg_next(host->sg);
+	host->sg_count--;
+}
+
+static void alcor_trigger_data_transfer(struct alcor_sdmmc_host *host,
+					bool early)
+{
+	struct alcor_pci_priv *priv = host->alcor_pci;
+	struct mmc_data *data = host->data;
+	u8 ctrl = 0;
+
+	if (data->flags & MMC_DATA_WRITE)
+		ctrl |= AU6601_DATA_WRITE;
+
+	if (data->host_cookie == COOKIE_MAPPED) {
+		if (host->early_data) {
+			host->early_data = false;
+			return;
+		}
+
+		host->early_data = early;
+
+		alcor_data_set_dma(host);
+		ctrl |= AU6601_DATA_DMA_MODE;
+		host->dma_on = 1;
+		alcor_write32(priv, data->sg_count * 0x1000,
+			       AU6601_REG_BLOCK_SIZE);
+	} else {
+		alcor_write32(priv, data->blksz, AU6601_REG_BLOCK_SIZE);
+	}
+
+	alcor_write8(priv, ctrl | AU6601_DATA_START_XFER,
+		      AU6601_DATA_XFER_CTRL);
+}
+
+static void alcor_trf_block_pio(struct alcor_sdmmc_host *host, bool read)
+{
+	struct alcor_pci_priv *priv = host->alcor_pci;
+	size_t blksize, len;
+	u8 *buf;
+
+	if (!host->blocks)
+		return;
+
+	if (host->dma_on) {
+		dev_err(host->dev, "configured DMA but got PIO request.\n");
+		return;
+	}
+
+	if (!!(host->data->flags & MMC_DATA_READ) != read) {
+		dev_err(host->dev, "got unexpected direction %i != %i\n",
+			!!(host->data->flags & MMC_DATA_READ), read);
+	}
+
+	if (!sg_miter_next(&host->sg_miter))
+		return;
+
+	blksize = host->data->blksz;
+	len = min(host->sg_miter.length, blksize);
+
+	dev_dbg(host->dev, "PIO, %s block size: 0x%zx\n",
+		read ? "read" : "write", blksize);
+
+	host->sg_miter.consumed = len;
+	host->blocks--;
+
+	buf = host->sg_miter.addr;
+
+	if (read)
+		ioread32_rep(priv->iobase + AU6601_REG_BUFFER, buf, len >> 2);
+	else
+		iowrite32_rep(priv->iobase + AU6601_REG_BUFFER, buf, len >> 2);
+
+	sg_miter_stop(&host->sg_miter);
+}
+
+static void alcor_prepare_sg_miter(struct alcor_sdmmc_host *host)
+{
+	unsigned int flags = SG_MITER_ATOMIC;
+	struct mmc_data *data = host->data;
+
+	if (data->flags & MMC_DATA_READ)
+		flags |= SG_MITER_TO_SG;
+	else
+		flags |= SG_MITER_FROM_SG;
+	sg_miter_start(&host->sg_miter, data->sg, data->sg_len, flags);
+}
+
+static void alcor_prepare_data(struct alcor_sdmmc_host *host,
+			       struct mmc_command *cmd)
+{
+	struct mmc_data *data = cmd->data;
+
+	if (!data)
+		return;
+
+
+	host->data = data;
+	host->data->bytes_xfered = 0;
+	host->blocks = data->blocks;
+	host->sg = data->sg;
+	host->sg_count = data->sg_count;
+	dev_dbg(host->dev, "prepare DATA: sg %i, blocks: %i\n",
+			host->sg_count, host->blocks);
+
+	if (data->host_cookie != COOKIE_MAPPED)
+		alcor_prepare_sg_miter(host);
+
+	alcor_trigger_data_transfer(host, true);
+}
+
+static void alcor_send_cmd(struct alcor_sdmmc_host *host,
+			   struct mmc_command *cmd, bool set_timeout)
+{
+	struct alcor_pci_priv *priv = host->alcor_pci;
+	unsigned long timeout = 0;
+	u8 ctrl = 0;
+
+	host->cmd = cmd;
+	alcor_prepare_data(host, cmd);
+
+	dev_dbg(host->dev, "send CMD. opcode: 0x%02x, arg; 0x%08x\n",
+		cmd->opcode, cmd->arg);
+	alcor_write8(priv, cmd->opcode | 0x40, AU6601_REG_CMD_OPCODE);
+	alcor_write32be(priv, cmd->arg, AU6601_REG_CMD_ARG);
+
+	switch (mmc_resp_type(cmd)) {
+	case MMC_RSP_NONE:
+		ctrl = AU6601_CMD_NO_RESP;
+		break;
+	case MMC_RSP_R1:
+		ctrl = AU6601_CMD_6_BYTE_CRC;
+		break;
+	case MMC_RSP_R1B:
+		ctrl = AU6601_CMD_6_BYTE_CRC | AU6601_CMD_STOP_WAIT_RDY;
+		break;
+	case MMC_RSP_R2:
+		ctrl = AU6601_CMD_17_BYTE_CRC;
+		break;
+	case MMC_RSP_R3:
+		ctrl = AU6601_CMD_6_BYTE_WO_CRC;
+		break;
+	default:
+		dev_err(host->dev, "%s: cmd->flag (0x%02x) is not valid\n",
+			mmc_hostname(host->mmc), mmc_resp_type(cmd));
+		break;
+	}
+
+	if (set_timeout) {
+		if (!cmd->data && cmd->busy_timeout)
+			timeout = cmd->busy_timeout;
+		else
+			timeout = 10000;
+
+		schedule_delayed_work(&host->timeout_work,
+				      msecs_to_jiffies(timeout));
+	}
+
+	dev_dbg(host->dev, "xfer ctrl: 0x%02x; timeout: %lu\n", ctrl, timeout);
+	alcor_write8(priv, ctrl | AU6601_CMD_START_XFER,
+				 AU6601_CMD_XFER_CTRL);
+}
+
+static void alcor_request_complete(struct alcor_sdmmc_host *host,
+				   bool cancel_timeout)
+{
+	struct mmc_request *mrq;
+
+	/*
+	 * If this work gets rescheduled while running, it will
+	 * be run again afterwards but without any active request.
+	 */
+	if (!host->mrq)
+		return;
+
+	if (cancel_timeout)
+		cancel_delayed_work(&host->timeout_work);
+
+	mrq = host->mrq;
+
+	host->mrq = NULL;
+	host->cmd = NULL;
+	host->data = NULL;
+	host->dma_on = 0;
+
+	mmc_request_done(host->mmc, mrq);
+}
+
+static void alcor_finish_data(struct alcor_sdmmc_host *host)
+{
+	struct mmc_data *data;
+
+	data = host->data;
+	host->data = NULL;
+	host->dma_on = 0;
+
+	/*
+	 * The specification states that the block count register must
+	 * be updated, but it does not specify at what point in the
+	 * data flow. That makes the register entirely useless to read
+	 * back so we have to assume that nothing made it to the card
+	 * in the event of an error.
+	 */
+	if (data->error)
+		data->bytes_xfered = 0;
+	else
+		data->bytes_xfered = data->blksz * data->blocks;
+
+	/*
+	 * Need to send CMD12 if -
+	 * a) open-ended multiblock transfer (no CMD23)
+	 * b) error in multiblock transfer
+	 */
+	if (data->stop &&
+	    (data->error ||
+	     !host->mrq->sbc)) {
+
+		/*
+		 * The controller needs a reset of internal state machines
+		 * upon error conditions.
+		 */
+		if (data->error)
+			alcor_reset(host, AU6601_RESET_CMD | AU6601_RESET_DATA);
+
+		alcor_unmask_sd_irqs(host);
+		alcor_send_cmd(host, data->stop, false);
+		return;
+	}
+
+	alcor_request_complete(host, 1);
+}
+
+static void alcor_err_irq(struct alcor_sdmmc_host *host, u32 intmask)
+{
+	dev_dbg(host->dev, "ERR IRQ %x\n", intmask);
+
+	if (host->cmd) {
+		if (intmask & AU6601_INT_CMD_TIMEOUT_ERR)
+			host->cmd->error = -ETIMEDOUT;
+		else
+			host->cmd->error = -EILSEQ;
+	}
+
+	if (host->data) {
+		if (intmask & AU6601_INT_DATA_TIMEOUT_ERR)
+			host->data->error = -ETIMEDOUT;
+		else
+			host->data->error = -EILSEQ;
+
+		host->data->bytes_xfered = 0;
+	}
+
+	alcor_reset(host, AU6601_RESET_CMD | AU6601_RESET_DATA);
+	alcor_request_complete(host, 1);
+}
+
+static int alcor_cmd_irq_done(struct alcor_sdmmc_host *host, u32 intmask)
+{
+	struct alcor_pci_priv *priv = host->alcor_pci;
+
+	intmask &= AU6601_INT_CMD_END;
+
+	if (!intmask)
+		return true;
+
+	/* got CMD_END but no CMD is in progress, wake thread an process the
+	 * error
+	 */
+	if (!host->cmd)
+		return false;
+
+	if (host->cmd->flags & MMC_RSP_PRESENT) {
+		struct mmc_command *cmd = host->cmd;
+
+		cmd->resp[0] = alcor_read32be(priv, AU6601_REG_CMD_RSP0);
+		dev_dbg(host->dev, "RSP0: 0x%04x\n", cmd->resp[0]);
+		if (host->cmd->flags & MMC_RSP_136) {
+			cmd->resp[1] =
+				alcor_read32be(priv, AU6601_REG_CMD_RSP1);
+			cmd->resp[2] =
+				alcor_read32be(priv, AU6601_REG_CMD_RSP2);
+			cmd->resp[3] =
+				alcor_read32be(priv, AU6601_REG_CMD_RSP3);
+			dev_dbg(host->dev, "RSP1,2,3: 0x%04x 0x%04x 0x%04x\n",
+				cmd->resp[1], cmd->resp[2], cmd->resp[3]);
+		}
+
+	}
+
+	host->cmd->error = 0;
+
+	/* Processed actual command. */
+	if (!host->data)
+		return false;
+
+	alcor_trigger_data_transfer(host, false);
+	host->cmd = NULL;
+	return true;
+}
+
+static void alcor_cmd_irq_thread(struct alcor_sdmmc_host *host, u32 intmask)
+{
+	intmask &= AU6601_INT_CMD_END;
+
+	if (!intmask)
+		return;
+
+	if (!host->cmd && intmask & AU6601_INT_CMD_END) {
+		dev_dbg(host->dev, "Got command interrupt 0x%08x even though no command operation was in progress.\n",
+			intmask);
+	}
+
+	/* Processed actual command. */
+	if (!host->data)
+		alcor_request_complete(host, 1);
+	else
+		alcor_trigger_data_transfer(host, false);
+	host->cmd = NULL;
+}
+
+static int alcor_data_irq_done(struct alcor_sdmmc_host *host, u32 intmask)
+{
+	u32 tmp;
+
+	intmask &= AU6601_INT_DATA_MASK;
+
+	/* nothing here to do */
+	if (!intmask)
+		return 1;
+
+	/* we was too fast and got DATA_END after it was processed?
+	 * lets ignore it for now.
+	 */
+	if (!host->data && intmask == AU6601_INT_DATA_END)
+		return 1;
+
+	/* looks like an error, so lets handle it. */
+	if (!host->data)
+		return 0;
+
+	tmp = intmask & (AU6601_INT_READ_BUF_RDY | AU6601_INT_WRITE_BUF_RDY
+			 | AU6601_INT_DMA_END);
+	switch (tmp) {
+	case 0:
+		break;
+	case AU6601_INT_READ_BUF_RDY:
+		alcor_trf_block_pio(host, true);
+		if (!host->blocks)
+			break;
+		alcor_trigger_data_transfer(host, false);
+		return 1;
+	case AU6601_INT_WRITE_BUF_RDY:
+		alcor_trf_block_pio(host, false);
+		if (!host->blocks)
+			break;
+		alcor_trigger_data_transfer(host, false);
+		return 1;
+	case AU6601_INT_DMA_END:
+		if (!host->sg_count)
+			break;
+
+		alcor_data_set_dma(host);
+		break;
+	default:
+		dev_err(host->dev, "Got READ_BUF_RDY and WRITE_BUF_RDY at same time\n");
+		break;
+	}
+
+	if (intmask & AU6601_INT_DATA_END)
+		return 0;
+
+	return 1;
+}
+
+static void alcor_data_irq_thread(struct alcor_sdmmc_host *host, u32 intmask)
+{
+	intmask &= AU6601_INT_DATA_MASK;
+
+	if (!intmask)
+		return;
+
+	if (!host->data) {
+		dev_dbg(host->dev, "Got data interrupt 0x%08x even though no data operation was in progress.\n",
+			intmask);
+		alcor_reset(host, AU6601_RESET_DATA);
+		return;
+	}
+
+	if (alcor_data_irq_done(host, intmask))
+		return;
+
+	if ((intmask & AU6601_INT_DATA_END) || !host->blocks ||
+	    (host->dma_on && !host->sg_count))
+		alcor_finish_data(host);
+}
+
+static void alcor_cd_irq(struct alcor_sdmmc_host *host, u32 intmask)
+{
+	dev_dbg(host->dev, "card %s\n",
+		intmask & AU6601_INT_CARD_REMOVE ? "removed" : "inserted");
+
+	if (host->mrq) {
+		dev_dbg(host->dev, "cancel all pending tasks.\n");
+
+		if (host->data)
+			host->data->error = -ENOMEDIUM;
+
+		if (host->cmd)
+			host->cmd->error = -ENOMEDIUM;
+		else
+			host->mrq->cmd->error = -ENOMEDIUM;
+
+		alcor_request_complete(host, 1);
+	}
+
+	mmc_detect_change(host->mmc, msecs_to_jiffies(1));
+}
+
+static irqreturn_t alcor_irq_thread(int irq, void *d)
+{
+	struct alcor_sdmmc_host *host = d;
+	irqreturn_t ret = IRQ_HANDLED;
+	u32 intmask, tmp;
+
+	mutex_lock(&host->cmd_mutex);
+
+	intmask = host->irq_status_sd;
+
+	/* some thing bad */
+	if (unlikely(!intmask || AU6601_INT_ALL_MASK == intmask)) {
+		dev_dbg(host->dev, "unexpected IRQ: 0x%04x\n", intmask);
+		ret = IRQ_NONE;
+		goto exit;
+	}
+
+	tmp = intmask & (AU6601_INT_CMD_MASK | AU6601_INT_DATA_MASK);
+	if (tmp) {
+		if (tmp & AU6601_INT_ERROR_MASK)
+			alcor_err_irq(host, tmp);
+		else {
+			alcor_cmd_irq_thread(host, tmp);
+			alcor_data_irq_thread(host, tmp);
+		}
+		intmask &= ~(AU6601_INT_CMD_MASK | AU6601_INT_DATA_MASK);
+	}
+
+	if (intmask & (AU6601_INT_CARD_INSERT | AU6601_INT_CARD_REMOVE)) {
+		alcor_cd_irq(host, intmask);
+		intmask &= ~(AU6601_INT_CARD_INSERT | AU6601_INT_CARD_REMOVE);
+	}
+
+	if (intmask & AU6601_INT_OVER_CURRENT_ERR) {
+		dev_warn(host->dev,
+			 "warning: over current detected!\n");
+		intmask &= ~AU6601_INT_OVER_CURRENT_ERR;
+	}
+
+	if (intmask)
+		dev_dbg(host->dev, "got not handled IRQ: 0x%04x\n", intmask);
+
+exit:
+	mutex_unlock(&host->cmd_mutex);
+	alcor_unmask_sd_irqs(host);
+	return ret;
+}
+
+
+static irqreturn_t alcor_irq(int irq, void *d)
+{
+	struct alcor_sdmmc_host *host = d;
+	struct alcor_pci_priv *priv = host->alcor_pci;
+	u32 status, tmp;
+	irqreturn_t ret;
+	int cmd_done, data_done;
+
+	status = alcor_read32(priv, AU6601_REG_INT_STATUS);
+	if (!status)
+		return IRQ_NONE;
+
+	alcor_write32(priv, status, AU6601_REG_INT_STATUS);
+
+	tmp = status & (AU6601_INT_READ_BUF_RDY | AU6601_INT_WRITE_BUF_RDY
+			| AU6601_INT_DATA_END | AU6601_INT_DMA_END
+			| AU6601_INT_CMD_END);
+	if (tmp == status) {
+		cmd_done = alcor_cmd_irq_done(host, tmp);
+		data_done = alcor_data_irq_done(host, tmp);
+		/* use fast path for simple tasks */
+		if (cmd_done && data_done) {
+			ret = IRQ_HANDLED;
+			goto alcor_irq_done;
+		}
+	}
+
+	host->irq_status_sd = status;
+	ret = IRQ_WAKE_THREAD;
+	alcor_mask_sd_irqs(host);
+alcor_irq_done:
+	return ret;
+}
+
+static void alcor_set_clock(struct alcor_sdmmc_host *host, unsigned int clock)
+{
+	struct alcor_pci_priv *priv = host->alcor_pci;
+	unsigned int clock_out = 0;
+	int i, diff = 0x7fffffff, tmp_clock = 0;
+	u16 clk_src = 0;
+	u8 clk_div = 0;
+
+	if (clock == 0) {
+		alcor_write16(priv, 0, AU6601_CLK_SELECT);
+		return;
+	}
+
+	for (i = 0; i < ARRAY_SIZE(alcor_pll_cfg); i++) {
+		unsigned int tmp_div, tmp_diff;
+		const struct alcor_pll_conf *cfg = &alcor_pll_cfg[i];
+
+		tmp_div = DIV_ROUND_UP(cfg->clk_src_freq, clock);
+		if (cfg->min_div > tmp_div || tmp_div > cfg->max_div)
+			continue;
+
+		tmp_clock = DIV_ROUND_UP(cfg->clk_src_freq, tmp_div);
+		tmp_diff = abs(clock - tmp_clock);
+
+		if (tmp_diff >= 0 && tmp_diff < diff) {
+			diff = tmp_diff;
+			clk_src = cfg->clk_src_reg;
+			clk_div = tmp_div;
+			clock_out = tmp_clock;
+		}
+	}
+
+	clk_src |= ((clk_div - 1) << 8);
+	clk_src |= AU6601_CLK_ENABLE;
+
+	dev_dbg(host->dev, "set freq %d cal freq %d, use div %d, mod %x\n",
+			clock, tmp_clock, clk_div, clk_src);
+
+	alcor_write16(priv, clk_src, AU6601_CLK_SELECT);
+
+}
+
+static void alcor_set_timing(struct mmc_host *mmc, struct mmc_ios *ios)
+{
+	struct alcor_sdmmc_host *host = mmc_priv(mmc);
+
+	if (ios->timing == MMC_TIMING_LEGACY) {
+		alcor_rmw8(host, AU6601_CLK_DELAY,
+			    AU6601_CLK_POSITIVE_EDGE_ALL, 0);
+	} else {
+		alcor_rmw8(host, AU6601_CLK_DELAY,
+			    0, AU6601_CLK_POSITIVE_EDGE_ALL);
+	}
+}
+
+static void alcor_set_bus_width(struct mmc_host *mmc, struct mmc_ios *ios)
+{
+	struct alcor_sdmmc_host *host = mmc_priv(mmc);
+	struct alcor_pci_priv *priv = host->alcor_pci;
+
+	if (ios->bus_width == MMC_BUS_WIDTH_1) {
+		alcor_write8(priv, 0, AU6601_REG_BUS_CTRL);
+	} else if (ios->bus_width == MMC_BUS_WIDTH_4) {
+		alcor_write8(priv, AU6601_BUS_WIDTH_4BIT,
+			      AU6601_REG_BUS_CTRL);
+	} else
+		dev_err(host->dev, "Unknown BUS mode\n");
+
+}
+
+static int alcor_card_busy(struct mmc_host *mmc)
+{
+	struct alcor_sdmmc_host *host = mmc_priv(mmc);
+	struct alcor_pci_priv *priv = host->alcor_pci;
+	u8 status;
+
+	/* Check whether dat[0:3] low */
+	status = alcor_read8(priv, AU6601_DATA_PIN_STATE);
+
+	return !(status & AU6601_BUS_STAT_DAT_MASK);
+}
+
+static int alcor_get_cd(struct mmc_host *mmc)
+{
+	struct alcor_sdmmc_host *host = mmc_priv(mmc);
+	struct alcor_pci_priv *priv = host->alcor_pci;
+	u8 detect;
+
+	detect = alcor_read8(priv, AU6601_DETECT_STATUS)
+		& AU6601_DETECT_STATUS_M;
+	/* check if card is present then send command and data */
+	return (detect == AU6601_SD_DETECTED);
+}
+
+static int alcor_get_ro(struct mmc_host *mmc)
+{
+	struct alcor_sdmmc_host *host = mmc_priv(mmc);
+	struct alcor_pci_priv *priv = host->alcor_pci;
+	u8 status;
+
+	/* get write protect pin status */
+	status = alcor_read8(priv, AU6601_INTERFACE_MODE_CTRL);
+
+	return !!(status & AU6601_SD_CARD_WP);
+}
+
+static void alcor_request(struct mmc_host *mmc, struct mmc_request *mrq)
+{
+	struct alcor_sdmmc_host *host = mmc_priv(mmc);
+
+	mutex_lock(&host->cmd_mutex);
+
+	host->mrq = mrq;
+
+	/* check if card is present then send command and data */
+	if (alcor_get_cd(mmc))
+		alcor_send_cmd(host, mrq->cmd, true);
+	else {
+		mrq->cmd->error = -ENOMEDIUM;
+		alcor_request_complete(host, 1);
+	}
+
+	mutex_unlock(&host->cmd_mutex);
+}
+
+static void alcor_pre_req(struct mmc_host *mmc,
+			   struct mmc_request *mrq)
+{
+	struct alcor_sdmmc_host *host = mmc_priv(mmc);
+	struct mmc_data *data = mrq->data;
+	struct mmc_command *cmd = mrq->cmd;
+	struct scatterlist *sg;
+	unsigned int i, sg_len;
+
+	if (!data || !cmd)
+		return;
+
+	data->host_cookie = COOKIE_UNMAPPED;
+
+	/* FIXME: looks like the DMA engine works only with CMD18 */
+	if (cmd->opcode != 18)
+		return;
+	/*
+	 * We don't do DMA on "complex" transfers, i.e. with
+	 * non-word-aligned buffers or lengths. Also, we don't bother
+	 * with all the DMA setup overhead for short transfers.
+	 */
+	if (data->blocks * data->blksz < AU6601_MAX_DMA_BLOCK_SIZE)
+		return;
+
+	if (data->blksz & 3)
+		return;
+
+	for_each_sg(data->sg, sg, data->sg_len, i) {
+		if (sg->length != AU6601_MAX_DMA_BLOCK_SIZE)
+			return;
+	}
+
+	/* This data might be unmapped at this time */
+
+	sg_len = dma_map_sg(host->dev, data->sg, data->sg_len,
+			    mmc_get_dma_dir(data));
+	if (sg_len)
+		data->host_cookie = COOKIE_MAPPED;
+
+	data->sg_count = sg_len;
+}
+
+static void alcor_post_req(struct mmc_host *mmc,
+			    struct mmc_request *mrq,
+			    int err)
+{
+	struct alcor_sdmmc_host *host = mmc_priv(mmc);
+	struct mmc_data *data = mrq->data;
+
+	if (!data)
+		return;
+
+	if (data->host_cookie == COOKIE_MAPPED) {
+		dma_unmap_sg(host->dev,
+			     data->sg,
+			     data->sg_len,
+			     mmc_get_dma_dir(data));
+	}
+
+	data->host_cookie = COOKIE_UNMAPPED;
+}
+
+static void alcor_set_power_mode(struct mmc_host *mmc, struct mmc_ios *ios)
+{
+	struct alcor_sdmmc_host *host = mmc_priv(mmc);
+	struct alcor_pci_priv *priv = host->alcor_pci;
+
+	switch (ios->power_mode) {
+	case MMC_POWER_OFF:
+		alcor_set_clock(host, ios->clock);
+		/* set all pins to input */
+		alcor_write8(priv, 0, AU6601_OUTPUT_ENABLE);
+		/* turn of VDD */
+		alcor_write8(priv, 0, AU6601_POWER_CONTROL);
+		break;
+	case MMC_POWER_UP:
+		break;
+	case MMC_POWER_ON:
+		/* This is most trickiest part. The order and timings of
+		 * instructions seems to play important role. Any changes may
+		 * confuse internal state engine if this HW.
+		 * FIXME: If we will ever get access to documentation, then this
+		 * part should be reviewed again.
+		 */
+
+		/* enable SD card mode */
+		alcor_write8(priv, AU6601_SD_CARD,
+			      AU6601_ACTIVE_CTRL);
+		/* set signal voltage to 3.3V */
+		alcor_write8(priv, 0, AU6601_OPT);
+		/* no documentation about clk delay, for now just try to mimic
+		 * original driver.
+		 */
+		alcor_write8(priv, 0x20, AU6601_CLK_DELAY);
+		/* set BUS width to 1 bit */
+		alcor_write8(priv, 0, AU6601_REG_BUS_CTRL);
+		/* set CLK first time */
+		alcor_set_clock(host, ios->clock);
+		/* power on VDD */
+		alcor_write8(priv, AU6601_SD_CARD,
+			      AU6601_POWER_CONTROL);
+		/* wait until the CLK will get stable */
+		mdelay(20);
+		/* set CLK again, mimic original driver. */
+		alcor_set_clock(host, ios->clock);
+
+		/* enable output */
+		alcor_write8(priv, AU6601_SD_CARD,
+			      AU6601_OUTPUT_ENABLE);
+		/* The clk will not work on au6621. We need to trigger data
+		 * transfer.
+		 */
+		alcor_write8(priv, AU6601_DATA_WRITE,
+			      AU6601_DATA_XFER_CTRL);
+		/* configure timeout. Not clear what exactly it means. */
+		alcor_write8(priv, 0x7d, AU6601_TIME_OUT_CTRL);
+		mdelay(100);
+		break;
+	default:
+		dev_err(host->dev, "Unknown power parameter\n");
+	}
+}
+
+static void alcor_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
+{
+	struct alcor_sdmmc_host *host = mmc_priv(mmc);
+
+	mutex_lock(&host->cmd_mutex);
+
+	dev_dbg(host->dev, "set ios. bus width: %x, power mode: %x\n",
+		ios->bus_width, ios->power_mode);
+
+	if (ios->power_mode != host->cur_power_mode) {
+		alcor_set_power_mode(mmc, ios);
+		host->cur_power_mode = ios->power_mode;
+	} else {
+		alcor_set_timing(mmc, ios);
+		alcor_set_bus_width(mmc, ios);
+		alcor_set_clock(host, ios->clock);
+	}
+
+	mutex_unlock(&host->cmd_mutex);
+}
+
+static int alcor_signal_voltage_switch(struct mmc_host *mmc,
+				       struct mmc_ios *ios)
+{
+	struct alcor_sdmmc_host *host = mmc_priv(mmc);
+
+	mutex_lock(&host->cmd_mutex);
+
+	switch (ios->signal_voltage) {
+	case MMC_SIGNAL_VOLTAGE_330:
+		alcor_rmw8(host, AU6601_OPT, AU6601_OPT_SD_18V, 0);
+		break;
+	case MMC_SIGNAL_VOLTAGE_180:
+		alcor_rmw8(host, AU6601_OPT, 0, AU6601_OPT_SD_18V);
+		break;
+	default:
+		/* No signal voltage switch required */
+		break;
+	}
+
+	mutex_unlock(&host->cmd_mutex);
+	return 0;
+}
+
+static const struct mmc_host_ops alcor_sdc_ops = {
+	.card_busy	= alcor_card_busy,
+	.get_cd		= alcor_get_cd,
+	.get_ro		= alcor_get_ro,
+	.post_req	= alcor_post_req,
+	.pre_req	= alcor_pre_req,
+	.request	= alcor_request,
+	.set_ios	= alcor_set_ios,
+	.start_signal_voltage_switch = alcor_signal_voltage_switch,
+};
+
+static void alcor_timeout_timer(struct work_struct *work)
+{
+	struct delayed_work *d = to_delayed_work(work);
+	struct alcor_sdmmc_host *host = container_of(d, struct alcor_sdmmc_host,
+						timeout_work);
+	mutex_lock(&host->cmd_mutex);
+
+	dev_dbg(host->dev, "triggered timeout\n");
+	if (host->mrq) {
+		dev_err(host->dev, "Timeout waiting for hardware interrupt.\n");
+
+		if (host->data) {
+			host->data->error = -ETIMEDOUT;
+		} else {
+			if (host->cmd)
+				host->cmd->error = -ETIMEDOUT;
+			else
+				host->mrq->cmd->error = -ETIMEDOUT;
+		}
+
+		alcor_reset(host, AU6601_RESET_CMD | AU6601_RESET_DATA);
+		alcor_request_complete(host, 0);
+	}
+
+	mmiowb();
+	mutex_unlock(&host->cmd_mutex);
+}
+
+static void alcor_hw_init(struct alcor_sdmmc_host *host)
+{
+	struct alcor_pci_priv *priv = host->alcor_pci;
+	struct alcor_dev_cfg *cfg = priv->cfg;
+
+	/* FIXME: This part is a mimics HW init of original driver.
+	 * If we will ever get access to documentation, then this part
+	 * should be reviewed again.
+	 */
+
+	/* reset command state engine */
+	alcor_reset(host, AU6601_RESET_CMD);
+
+	alcor_write8(priv, 0, AU6601_DMA_BOUNDARY);
+	/* enable sd card mode */
+	alcor_write8(priv, AU6601_SD_CARD, AU6601_ACTIVE_CTRL);
+
+	/* set BUS width to 1 bit */
+	alcor_write8(priv, 0, AU6601_REG_BUS_CTRL);
+
+	/* reset data state engine */
+	alcor_reset(host, AU6601_RESET_DATA);
+	/* Not sure if a voodoo with AU6601_DMA_BOUNDARY is really needed */
+	alcor_write8(priv, 0, AU6601_DMA_BOUNDARY);
+
+	alcor_write8(priv, 0, AU6601_INTERFACE_MODE_CTRL);
+	/* not clear what we are doing here. */
+	alcor_write8(priv, 0x44, AU6601_PAD_DRIVE0);
+	alcor_write8(priv, 0x44, AU6601_PAD_DRIVE1);
+	alcor_write8(priv, 0x00, AU6601_PAD_DRIVE2);
+
+	/* for 6601 - dma_boundary; for 6621 - dma_page_cnt
+	 * exact meaning of this register is not clear.
+	 */
+	alcor_write8(priv, cfg->dma, AU6601_DMA_BOUNDARY);
+
+	/* make sure all pins are set to input and VDD is off */
+	alcor_write8(priv, 0, AU6601_OUTPUT_ENABLE);
+	alcor_write8(priv, 0, AU6601_POWER_CONTROL);
+
+	alcor_write8(priv, AU6601_DETECT_EN, AU6601_DETECT_STATUS);
+	/* now we should be safe to enable IRQs */
+	alcor_unmask_sd_irqs(host);
+}
+
+static void alcor_hw_uninit(struct alcor_sdmmc_host *host)
+{
+	struct alcor_pci_priv *priv = host->alcor_pci;
+
+	alcor_mask_sd_irqs(host);
+	alcor_reset(host, AU6601_RESET_CMD | AU6601_RESET_DATA);
+
+	alcor_write8(priv, 0, AU6601_DETECT_STATUS);
+
+	alcor_write8(priv, 0, AU6601_OUTPUT_ENABLE);
+	alcor_write8(priv, 0, AU6601_POWER_CONTROL);
+
+	alcor_write8(priv, 0, AU6601_OPT);
+}
+
+static void alcor_init_mmc(struct alcor_sdmmc_host *host)
+{
+	struct mmc_host *mmc = host->mmc;
+
+	mmc->f_min = AU6601_MIN_CLOCK;
+	mmc->f_max = AU6601_MAX_CLOCK;
+	mmc->ocr_avail = MMC_VDD_33_34;
+	mmc->caps = MMC_CAP_4_BIT_DATA | MMC_CAP_SD_HIGHSPEED
+		| MMC_CAP_UHS_SDR12 | MMC_CAP_UHS_SDR25 | MMC_CAP_UHS_SDR50
+		| MMC_CAP_UHS_SDR104 | MMC_CAP_UHS_DDR50;
+	mmc->caps2 = MMC_CAP2_NO_SDIO;
+	mmc->ops = &alcor_sdc_ops;
+
+	/* Hardware cannot do scatter lists */
+	mmc->max_segs = AU6601_MAX_DMA_SEGMENTS;
+	mmc->max_seg_size = AU6601_MAX_DMA_BLOCK_SIZE;
+
+	mmc->max_blk_size = mmc->max_seg_size;
+	mmc->max_blk_count = mmc->max_segs;
+
+	mmc->max_req_size = mmc->max_seg_size * mmc->max_segs;
+}
+
+static int alcor_pci_sdmmc_drv_probe(struct platform_device *pdev)
+{
+	struct alcor_pci_priv *priv = pdev->dev.platform_data;
+	struct mmc_host *mmc;
+	struct alcor_sdmmc_host *host;
+	int ret;
+
+	mmc = mmc_alloc_host(sizeof(*host), &pdev->dev);
+	if (!mmc) {
+		dev_err(&pdev->dev, "Can't allocate MMC\n");
+		return -ENOMEM;
+	}
+
+	host = mmc_priv(mmc);
+	host->mmc = mmc;
+	host->dev = &pdev->dev;
+	host->cur_power_mode = MMC_POWER_UNDEFINED;
+	host->alcor_pci = priv;
+
+	/* make sure irqs are disabled */
+	alcor_write32(priv, 0, AU6601_REG_INT_ENABLE);
+	alcor_write32(priv, 0, AU6601_MS_INT_ENABLE);
+
+	ret = devm_request_threaded_irq(&pdev->dev, priv->irq,
+			alcor_irq, alcor_irq_thread, IRQF_SHARED,
+			DRV_NAME_ALCOR_PCI_SDMMC, host);
+
+	if (ret) {
+		dev_err(&pdev->dev, "Failed to get irq for data line\n");
+		return ret;
+	}
+
+	mutex_init(&host->cmd_mutex);
+	INIT_DELAYED_WORK(&host->timeout_work, alcor_timeout_timer);
+
+	alcor_init_mmc(host);
+	alcor_hw_init(host);
+
+	dev_set_drvdata(&pdev->dev, host);
+	mmc_add_host(mmc);
+	return 0;
+}
+
+static int alcor_pci_sdmmc_drv_remove(struct platform_device *pdev)
+{
+	struct alcor_sdmmc_host *host = dev_get_drvdata(&pdev->dev);
+
+	if (cancel_delayed_work_sync(&host->timeout_work))
+		alcor_request_complete(host, 0);
+
+	alcor_hw_uninit(host);
+	mmc_remove_host(host->mmc);
+	mmc_free_host(host->mmc);
+
+	return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int alcor_pci_sdmmc_suspend(struct device *dev)
+{
+	struct alcor_sdmmc_host *host = dev_get_drvdata(dev);
+
+	if (cancel_delayed_work_sync(&host->timeout_work))
+		alcor_request_complete(host, 0);
+
+	alcor_hw_uninit(host);
+
+	return 0;
+}
+
+static int alcor_pci_sdmmc_resume(struct device *dev)
+{
+	struct alcor_sdmmc_host *host = dev_get_drvdata(dev);
+
+	alcor_hw_init(host);
+
+	return 0;
+}
+#endif /* CONFIG_PM_SLEEP */
+
+static SIMPLE_DEV_PM_OPS(alcor_mmc_pm_ops, alcor_pci_sdmmc_suspend,
+			 alcor_pci_sdmmc_resume);
+
+static const struct platform_device_id alcor_pci_sdmmc_ids[] = {
+	{
+		.name = DRV_NAME_ALCOR_PCI_SDMMC,
+	}, {
+		/* sentinel */
+	}
+};
+MODULE_DEVICE_TABLE(platform, alcor_pci_sdmmc_ids);
+
+static struct platform_driver alcor_pci_sdmmc_driver = {
+	.probe		= alcor_pci_sdmmc_drv_probe,
+	.remove		= alcor_pci_sdmmc_drv_remove,
+	.id_table	= alcor_pci_sdmmc_ids,
+	.driver		= {
+		.name	= DRV_NAME_ALCOR_PCI_SDMMC,
+		.pm	= &alcor_mmc_pm_ops
+	},
+};
+module_platform_driver(alcor_pci_sdmmc_driver);
+
+MODULE_AUTHOR("Oleksij Rempel <linux@rempel-privat.de>");
+MODULE_DESCRIPTION("PCI driver for Alcor Micro AU6601 Secure Digital Host Controller Interface");
+MODULE_LICENSE("GPL");