diff mbox

[v2] mmc: meson: Add driver for the SD/MMC host found on Amlogic MesonX SoCs

Message ID 1433926397-31376-1-git-send-email-carlo@caione.org (mailing list archive)
State New, archived
Headers show

Commit Message

Carlo Caione June 10, 2015, 8:53 a.m. UTC
From: Carlo Caione <carlo@endlessm.com>

Add a driver for the SD/MMC host found on the Amlogic MesonX SoCs. It
is an MMC controller which provides an interface between the
application processor and various memory cards. It supports the SD
specification v2.0 and the eMMC specification v4.41. It also supports
SDSC, SDHC and SDXC memory card default speed.

This patch adds also the binding documentation.

Signed-off-by: Carlo Caione <carlo@endlessm.com>
---

Changelog:

v2:
    * fix typo in commit message
    * avoid the bounce buffer (max_segs == 1)

---
 .../devicetree/bindings/mmc/meson-mmc.txt          |  38 ++
 drivers/mmc/host/Kconfig                           |   7 +
 drivers/mmc/host/Makefile                          |   1 +
 drivers/mmc/host/meson-mmc.c                       | 628 +++++++++++++++++++++
 4 files changed, 674 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/mmc/meson-mmc.txt
 create mode 100644 drivers/mmc/host/meson-mmc.c

Comments

Daniel Drake June 10, 2015, 1:44 p.m. UTC | #1
On Wed, Jun 10, 2015 at 2:53 AM, Carlo Caione <carlo@caione.org> wrote:
> +static int meson_mmc_map_dma(struct meson_mmc_host *host,
> +                            struct mmc_data *data,
> +                            unsigned int flags)
> +{      u32 i, dma_len;
> +       struct scatterlist *sg;
> +
> +       dma_len = dma_map_sg(mmc_dev(host->mmc), data->sg, data->sg_len,
> +                            ((data->flags & MMC_DATA_READ) ?
> +                            DMA_FROM_DEVICE : DMA_TO_DEVICE));
> +       if (dma_len == 0) {
> +               dev_err(mmc_dev(host->mmc), "dma_map_sg failed\n");
> +               return -ENOMEM;
> +       }
> +
> +       for_each_sg(data->sg, sg, data->sg_len, i) {
> +               if (sg->offset & 3 || sg->length & 3) {
> +                       dev_err(mmc_dev(host->mmc),
> +                               "unaligned scatterlist: os %x length %d\n",
> +                               sg->offset, sg->length);
> +                       return -EINVAL;
> +               }
> +       }

If the offset/length check fails here, do you leak the DMA mapping?
If so, can you do the offset/length check first to avoid that?

There should only ever be 1 entry in the scatterlist, right? In that
case you can do a simple check there, and then instead of looping,
just check the first entry in the scatterlist.

Daniel
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Carlo Caione June 11, 2015, 4:55 p.m. UTC | #2
On Wed, Jun 10, 2015 at 3:44 PM, Daniel Drake <drake@endlessm.com> wrote:
> On Wed, Jun 10, 2015 at 2:53 AM, Carlo Caione <carlo@caione.org> wrote:
>> +static int meson_mmc_map_dma(struct meson_mmc_host *host,
>> +                            struct mmc_data *data,
>> +                            unsigned int flags)
>> +{      u32 i, dma_len;
>> +       struct scatterlist *sg;
>> +
>> +       dma_len = dma_map_sg(mmc_dev(host->mmc), data->sg, data->sg_len,
>> +                            ((data->flags & MMC_DATA_READ) ?
>> +                            DMA_FROM_DEVICE : DMA_TO_DEVICE));
>> +       if (dma_len == 0) {
>> +               dev_err(mmc_dev(host->mmc), "dma_map_sg failed\n");
>> +               return -ENOMEM;
>> +       }
>> +
>> +       for_each_sg(data->sg, sg, data->sg_len, i) {
>> +               if (sg->offset & 3 || sg->length & 3) {
>> +                       dev_err(mmc_dev(host->mmc),
>> +                               "unaligned scatterlist: os %x length %d\n",
>> +                               sg->offset, sg->length);
>> +                       return -EINVAL;
>> +               }
>> +       }
>
> If the offset/length check fails here, do you leak the DMA mapping?
> If so, can you do the offset/length check first to avoid that?

Good idea. Fix in v3.

> There should only ever be 1 entry in the scatterlist, right? In that
> case you can do a simple check there, and then instead of looping,
> just check the first entry in the scatterlist.

Right.

I'm going to wait a couple of days for more comments before submitting v3.

Thanks,
diff mbox

Patch

diff --git a/Documentation/devicetree/bindings/mmc/meson-mmc.txt b/Documentation/devicetree/bindings/mmc/meson-mmc.txt
new file mode 100644
index 0000000..839569a
--- /dev/null
+++ b/Documentation/devicetree/bindings/mmc/meson-mmc.txt
@@ -0,0 +1,38 @@ 
+* Amlogic MesonX MMC controller
+
+The highspeed MMC host controller on Amlogic SoCs provides an interface
+for MMC, SD, SDIO and SDHC types of memory cards.
+
+Supported maximum speeds are the ones of the eMMC standard 4.41 as well
+as the speed of SD standard 2.0.
+
+Required properties:
+ - compatible : "amlogic,meson-mmc"
+ - reg : mmc controller base registers
+ - interrupts : mmc controller interrupt
+ - clocks : phandle to SDIO clock provider
+
+Optional properties:
+ - meson,sdio-port : 0 for SDIO port A, 1 for SDIO port B. (default: 0)
+ - for cd, bus-width and additional generic mmc parameters
+   please refer to mmc.txt within this directory
+
+Examples:
+	- Within .dtsi:
+	mmc0: mmc@c1108c20 {
+		compatible = "amlogic,meson-mmc";
+		reg = <0xc1108c20 0x20>;
+		interrupts = <0 28 1>;
+		clocks = <&clkc CLKID_CLK81>;
+		status = "disabled";
+	};
+
+	- Within .dts:
+	&mmc0 {
+		status = "okay";
+		pinctrl-0 = <&mmc0_sd_b_pins>;
+		pinctrl-names = "default";
+		meson,sdio-port = <1>;
+		cd-gpios = <&gpio CARD_6 0>;
+		cd-inverted;
+	};
diff --git a/drivers/mmc/host/Kconfig b/drivers/mmc/host/Kconfig
index b1f837e..e61b8d6 100644
--- a/drivers/mmc/host/Kconfig
+++ b/drivers/mmc/host/Kconfig
@@ -764,6 +764,13 @@  config MMC_REALTEK_USB
 	  Say Y here to include driver code to support SD/MMC card interface
 	  of Realtek RTS5129/39 series card reader
 
+config MMC_MESON
+	tristate "Amlogic MesonX SD/MMC Host Controller support"
+	depends on ARCH_MESON
+	help
+	  This selects support for the SD/MMC Host Controller on
+	  Amlogic MesonX SoCs.
+
 config MMC_SUNXI
 	tristate "Allwinner sunxi SD/MMC Host Controller support"
 	depends on ARCH_SUNXI
diff --git a/drivers/mmc/host/Makefile b/drivers/mmc/host/Makefile
index e3ab5b9..c0455e7 100644
--- a/drivers/mmc/host/Makefile
+++ b/drivers/mmc/host/Makefile
@@ -53,6 +53,7 @@  obj-$(CONFIG_MMC_VUB300)	+= vub300.o
 obj-$(CONFIG_MMC_USHC)		+= ushc.o
 obj-$(CONFIG_MMC_WMT)		+= wmt-sdmmc.o
 obj-$(CONFIG_MMC_MOXART)	+= moxart-mmc.o
+obj-$(CONFIG_MMC_MESON)		+= meson-mmc.o
 obj-$(CONFIG_MMC_SUNXI)		+= sunxi-mmc.o
 obj-$(CONFIG_MMC_USDHI6ROL0)	+= usdhi6rol0.o
 obj-$(CONFIG_MMC_TOSHIBA_PCI)	+= toshsd.o
diff --git a/drivers/mmc/host/meson-mmc.c b/drivers/mmc/host/meson-mmc.c
new file mode 100644
index 0000000..1021042
--- /dev/null
+++ b/drivers/mmc/host/meson-mmc.c
@@ -0,0 +1,628 @@ 
+/*
+ * mesonsd.c - Meson SDH Controller
+ *
+ * Copyright (C) 2015 Endless Mobile, Inc.
+ * Author: Carlo Caione <carlo@endlessm.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or (at
+ * your option) any later version.
+ */
+
+#define DRIVER_NAME	"meson-mmc"
+
+#define DEBUG
+
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/dma-mapping.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/ioport.h>
+#include <linux/platform_device.h>
+
+#include <linux/mmc/host.h>
+#include <linux/mmc/mmc.h>
+#include <linux/mmc/sdio.h>
+#include <linux/mmc/slot-gpio.h>
+
+#include <linux/of_address.h>
+#include <linux/of_gpio.h>
+#include <linux/of_platform.h>
+
+#define SDIO_ARGU		(0x00)
+#define SDIO_SEND		(0x04)
+#define SDIO_CONF		(0x08)
+#define SDIO_IRQS		(0x0c)
+#define SDIO_IRQC		(0x10)
+#define SDIO_MULT		(0x14)
+#define SDIO_ADDR		(0x18)
+#define SDIO_EXT		(0x1c)
+
+#define REG_IRQS_RESP_CRC7	BIT(5)
+#define REG_IRQS_RD_CRC16	BIT(6)
+#define REG_IRQS_WR_CRC16	BIT(7)
+#define REG_IRQS_CMD_INT	BIT(9)
+
+#define REG_IRQC_ARC_CMD_INT	BIT(4)
+#define REG_IRQC_SOFT_RESET	BIT(15)
+
+#define REG_CONF_WR_CRC_S	(29)
+#define REG_CONF_WR_NWR_S	(23)
+#define REG_CONF_M_END_S	(21)
+#define REG_CONF_ARGU_BITS_S	(12)
+#define REG_CONF_CLK_DIV_M	(0x3ff)
+#define REG_CONF_BUS_WIDTH	BIT(20)
+
+#define REG_MULT_PORT_SEL_M	(0x3)
+#define REG_MULT_RD_INDEX_M	(0x0f)
+#define REG_MULT_RD_INDEX_S	(12)
+#define REG_MULT_WR_RD_OUT_IND	BIT(8)
+
+#define REG_SEND_CMD_COMMAND_M	(0xff)
+#define REG_SEND_CMD_RESP_S	(8)
+#define REG_SEND_RESP_NO_CRC7	BIT(16)
+#define REG_SEND_RESP_HAVE_DATA	BIT(17)
+#define REG_SEND_RESP_CRC7_F_8	BIT(18)
+#define REG_SEND_CHECK_BUSY_D0	BIT(19)
+#define REG_SEND_CMD_SEND_DATA	BIT(20)
+#define REG_SEND_REP_PACK_N_M	(0xff)
+#define REG_SEND_REP_PACK_N_S	(24)
+
+#define REG_EXT_DAT_RW_NUM_M	(0x3fff)
+#define REG_EXT_DAT_RW_NUM_S	(16)
+
+#define CLK_DIV			(0x1f4)
+
+#define SDIO_BOUNCE_REQ_SIZE	(128 * 1024)
+
+enum mmcif_state {
+	STATE_IDLE,
+	STATE_REQUEST,
+	STATE_IOS,
+	STATE_TIMEOUT,
+	STATE_STOP,
+};
+
+struct meson_mmc_host {
+	struct mmc_host		*mmc;
+	struct mmc_request	*mrq;
+	struct delayed_work     timeout_work;
+	struct clk		*clk_sdio;
+	spinlock_t		lock;
+	void __iomem		*base;
+	long			timeout;
+	int			irq;
+	int			ferror;
+	unsigned int		bus_width;
+	unsigned int		port;
+	enum mmcif_state	state;
+};
+
+static int meson_mmc_clk_set_rate(struct mmc_host *mmc, struct mmc_ios *ios)
+{
+	struct meson_mmc_host *host = mmc_priv(mmc);
+	unsigned long clk_rate;
+	unsigned int clk_ios = ios->clock;
+	unsigned int clk_div;
+	u32 conf_reg;
+
+	clk_rate = clk_get_rate(host->clk_sdio) / 2;
+	if (clk_rate < 0) {
+		dev_err(mmc_dev(mmc), "cannot get clock rate\n");
+		return -EINVAL;
+	}
+
+	clk_div = clk_rate / clk_ios - !(clk_rate % clk_ios);
+
+	conf_reg = readl(host->base + SDIO_CONF);
+	conf_reg &= ~REG_CONF_CLK_DIV_M;
+	conf_reg |= clk_div;
+	writel(conf_reg, host->base + SDIO_CONF);
+
+	dev_dbg(mmc_dev(mmc), "clk_ios: %d, clk_div: %d, clk_rate: %ld\n",
+			clk_ios, clk_div, clk_rate);
+
+	return 0;
+}
+
+static void meson_mmc_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
+{
+	struct meson_mmc_host *host = mmc_priv(mmc);
+	u32 reg;
+
+	if (host->state != STATE_IDLE) {
+		dev_dbg(mmc_dev(mmc), "%s() rejected, state %u\n",
+			__func__, host->state);
+		return;
+	}
+
+	host->state = STATE_IOS;
+
+	reg = readl(host->base + SDIO_CONF);
+
+	switch (ios->bus_width) {
+	case MMC_BUS_WIDTH_1:
+		host->bus_width = 0;
+		reg &= ~REG_CONF_BUS_WIDTH;
+		dev_dbg(mmc_dev(mmc), "bus width: 1bit\n");
+		break;
+	case MMC_BUS_WIDTH_4:
+		host->bus_width = 1;
+		reg |= REG_CONF_BUS_WIDTH;
+		dev_dbg(mmc_dev(mmc), "bus width: 4bit\n");
+		break;
+	case MMC_BUS_WIDTH_8:
+	default:
+		dev_err(mmc_dev(mmc), "SDIO controller doesn't support 8bit data bus\n");
+		host->ferror = -EINVAL;
+		return;
+	}
+
+	writel(reg, host->base + SDIO_CONF);
+
+	if (ios->clock && ios->power_mode)
+		host->ferror = meson_mmc_clk_set_rate(mmc, ios);
+
+	host->state = STATE_IDLE;
+}
+
+static void meson_mmc_soft_reset(struct meson_mmc_host *host)
+{
+	u32 irqc;
+
+	irqc = readl(host->base + SDIO_IRQC);
+	irqc |= REG_IRQC_SOFT_RESET;
+	writel(irqc, host->base + SDIO_IRQC);
+	udelay(2);
+}
+
+static void meson_mmc_start_cmd(struct mmc_host *mmc,
+				struct mmc_request *mrq)
+{
+	struct meson_mmc_host *host = mmc_priv(mmc);
+	unsigned int pack_size;
+	u32 irqc, irqs, mult;
+	u32 send = 0;
+	u32 ext = 0;
+
+	switch (mmc_resp_type(mrq->cmd)) {
+	case MMC_RSP_R1:
+	case MMC_RSP_R1B:
+	case MMC_RSP_R3:
+		send |= (45 << REG_SEND_CMD_RESP_S);
+		break;
+	case MMC_RSP_R2:
+		send |= (133 << REG_SEND_CMD_RESP_S);
+		send |= REG_SEND_RESP_CRC7_F_8;
+		break;
+	default:
+		break;
+	}
+
+	if (!(mrq->cmd->flags & MMC_RSP_CRC))
+		send |= REG_SEND_RESP_NO_CRC7;
+
+	if (mrq->cmd->flags & MMC_RSP_BUSY)
+		send |= REG_SEND_CHECK_BUSY_D0;
+
+	if (mrq->data) {
+		send &= ~(REG_SEND_REP_PACK_N_M << REG_SEND_REP_PACK_N_S);
+		send |= ((mrq->data->blocks - 1) << REG_SEND_REP_PACK_N_S);
+
+		ext &= ~(REG_EXT_DAT_RW_NUM_M << REG_EXT_DAT_RW_NUM_S);
+		if (host->bus_width)
+			pack_size = mrq->data->blksz * 8 + (16 - 1) * 4;
+		else
+			pack_size = mrq->data->blksz * 8 + (16 - 1);
+		ext |= (pack_size << REG_EXT_DAT_RW_NUM_S);
+
+		if (mrq->data->flags & MMC_DATA_WRITE)
+			send |= REG_SEND_CMD_SEND_DATA;
+		else
+			send |= REG_SEND_RESP_HAVE_DATA;
+	}
+
+	send &= ~REG_SEND_CMD_COMMAND_M;
+	send |= (0x40 | mrq->cmd->opcode);
+
+	meson_mmc_soft_reset(host);
+
+	irqc = readl(host->base + SDIO_IRQC);
+	irqc |= REG_IRQC_ARC_CMD_INT;
+
+	irqs = readl(host->base + SDIO_IRQS);
+	irqs |= REG_IRQS_CMD_INT;
+
+	mult = readl(host->base + SDIO_MULT);
+	mult &= ~REG_MULT_PORT_SEL_M;
+	mult |= host->port;
+	mult |= (1 << 31);
+	writel(mult, host->base + SDIO_MULT);
+	writel(irqs, host->base + SDIO_IRQS);
+	writel(irqc, host->base + SDIO_IRQC);
+
+	writel(mrq->cmd->arg, host->base + SDIO_ARGU);
+	writel(ext, host->base + SDIO_EXT);
+	writel(send, host->base + SDIO_SEND);
+}
+
+static int meson_mmc_map_dma(struct meson_mmc_host *host,
+			     struct mmc_data *data,
+			     unsigned int flags)
+{	u32 i, dma_len;
+	struct scatterlist *sg;
+
+	dma_len = dma_map_sg(mmc_dev(host->mmc), data->sg, data->sg_len,
+			     ((data->flags & MMC_DATA_READ) ?
+			     DMA_FROM_DEVICE : DMA_TO_DEVICE));
+	if (dma_len == 0) {
+		dev_err(mmc_dev(host->mmc), "dma_map_sg failed\n");
+		return -ENOMEM;
+	}
+
+	for_each_sg(data->sg, sg, data->sg_len, i) {
+		if (sg->offset & 3 || sg->length & 3) {
+			dev_err(mmc_dev(host->mmc),
+				"unaligned scatterlist: os %x length %d\n",
+				sg->offset, sg->length);
+			return -EINVAL;
+		}
+	}
+
+	return 0;
+}
+
+static void meson_mmc_request(struct mmc_host *mmc, struct mmc_request *mrq)
+{
+	struct meson_mmc_host *host = mmc_priv(mmc);
+	struct mmc_command *cmd = mrq->cmd;
+	struct mmc_data *data = mrq->data;
+	unsigned long flags;
+	int ret;
+
+	spin_lock_irqsave(&host->lock, flags);
+
+	if (host->state != STATE_IDLE) {
+		dev_dbg(mmc_dev(mmc), "%s() rejected, state %u\n",
+			__func__, host->state);
+		mrq->cmd->error = -EAGAIN;
+		spin_unlock_irqrestore(&host->lock, flags);
+		mmc_request_done(mmc, mrq);
+		return;
+	}
+
+	if (host->ferror) {
+		cmd->error = host->ferror;
+		spin_unlock_irqrestore(&host->lock, flags);
+		mmc_request_done(mmc, mrq);
+		return;
+	}
+
+	dev_dbg(mmc_dev(mmc), "CMD%d(%08x) arg %x len %d flags %08x\n",
+		cmd->opcode & 0x3f, cmd->opcode, cmd->arg,
+		mrq->data ? mrq->data->blksz * mrq->data->blocks : 0,
+		mrq->cmd->flags);
+
+	/* Filter out CMD 5/52/53 */
+	if (cmd->opcode == SD_IO_SEND_OP_COND ||
+	    cmd->opcode == SD_IO_RW_DIRECT ||
+	    cmd->opcode == SD_IO_RW_EXTENDED) {
+		dev_dbg(mmc_dev(host->mmc), "CMD%d not supported\n",
+			cmd->opcode);
+		cmd->error = -EINVAL;
+		spin_unlock_irqrestore(&host->lock, flags);
+		mmc_request_done(mmc, mrq);
+		return;
+	}
+
+	host->state = STATE_REQUEST;
+
+	if (data) {
+		ret = meson_mmc_map_dma(host, data, data->flags);
+		if (ret < 0) {
+			dev_err(mmc_dev(mmc), "map DMA failed\n");
+			cmd->error = ret;
+			data->error = ret;
+			host->state = STATE_IDLE;
+			spin_unlock_irqrestore(&host->lock, flags);
+			mmc_request_done(mmc, mrq);
+			return;
+		}
+		writel(sg_dma_address(data->sg), host->base + SDIO_ADDR);
+	}
+
+	host->mrq = mrq;
+	schedule_delayed_work(&host->timeout_work, host->timeout);
+	meson_mmc_start_cmd(mmc, mrq);
+
+	spin_unlock_irqrestore(&host->lock, flags);
+}
+
+static irqreturn_t meson_mmc_irq(int irq, void *data)
+{
+	struct meson_mmc_host *host = (void *) data;
+	struct mmc_request *mrq = host->mrq;
+	u32 irqs;
+
+	irqs = readl(host->base + SDIO_IRQS);
+	if (mrq && (irqs & REG_IRQS_CMD_INT))
+		return IRQ_WAKE_THREAD;
+
+	return IRQ_HANDLED;
+}
+
+void meson_mmc_read_response(struct meson_mmc_host *host)
+{
+	struct mmc_command *cmd = host->mrq->cmd;
+	u32 mult;
+	int i, resp[4] = { 0 };
+
+	mult = readl(host->base + SDIO_MULT);
+	mult |= REG_MULT_WR_RD_OUT_IND;
+	mult &= ~(REG_MULT_RD_INDEX_M << REG_MULT_RD_INDEX_S);
+	writel(mult, host->base + SDIO_MULT);
+
+	if (cmd->flags & MMC_RSP_136) {
+		for (i = 0; i <= 3; i++)
+			resp[3 - i] = readl(host->base + SDIO_ARGU);
+		cmd->resp[0] = (resp[0] << 8) | ((resp[1] >> 24) & 0xff);
+		cmd->resp[1] = (resp[1] << 8) | ((resp[2] >> 24) & 0xff);
+		cmd->resp[2] = (resp[2] << 8) | ((resp[3] >> 24) & 0xff);
+		cmd->resp[3] = (resp[3] << 8);
+	} else if (cmd->flags & MMC_RSP_PRESENT) {
+		cmd->resp[0] = readl(host->base + SDIO_ARGU);
+	}
+}
+
+struct mmc_command meson_mmc_cmd = {
+	.opcode	= MMC_STOP_TRANSMISSION,
+	.flags	= MMC_RSP_SPI_R1B | MMC_RSP_R1B | MMC_CMD_AC,
+};
+
+struct mmc_request meson_mmc_stop = {
+	.cmd = &meson_mmc_cmd,
+};
+
+static irqreturn_t meson_mmc_irq_thread(int irq, void *irq_data)
+{
+	struct meson_mmc_host *host = (void *) irq_data;
+	struct mmc_data *data;
+	unsigned long flags;
+	struct mmc_request *mrq;
+	u32 irqs, send;
+
+	spin_lock_irqsave(&host->lock, flags);
+
+	cancel_delayed_work_sync(&host->timeout_work);
+	mrq = host->mrq;
+	data = mrq->data;
+
+	if (!mrq) {
+		spin_unlock_irqrestore(&host->lock, flags);
+		return IRQ_HANDLED;
+	}
+
+	if (host->state == STATE_STOP)
+		goto out;
+
+	if (host->state != STATE_REQUEST) {
+		dev_dbg(mmc_dev(host->mmc), "%s() rejected, state %u\n",
+			__func__, host->state);
+		mrq->cmd->error = -EAGAIN;
+		goto out;
+	}
+
+	irqs = readl(host->base + SDIO_IRQS);
+	send = readl(host->base + SDIO_SEND);
+
+	mrq->cmd->error = 0;
+
+	if (!data) {
+		if (!((irqs & REG_IRQS_RESP_CRC7) ||
+		      (send & REG_SEND_RESP_NO_CRC7)))
+			mrq->cmd->error = -EILSEQ;
+		else
+			meson_mmc_read_response(host);
+	} else {
+		if (!((irqs & REG_IRQS_RD_CRC16) ||
+		      (irqs & REG_IRQS_WR_CRC16))) {
+			mrq->cmd->error = -EILSEQ;
+		} else {
+			data->bytes_xfered = data->blksz * data->blocks;
+			dma_unmap_sg(mmc_dev(host->mmc), data->sg, data->sg_len,
+				     ((data->flags & MMC_DATA_READ) ?
+				     DMA_FROM_DEVICE : DMA_TO_DEVICE));
+
+			if (mrq->stop) {
+				host->state = STATE_STOP;
+				meson_mmc_start_cmd(host->mmc, &meson_mmc_stop);
+				spin_unlock_irqrestore(&host->lock, flags);
+				return IRQ_HANDLED;
+			}
+		}
+	}
+
+out:
+	host->state = STATE_IDLE;
+	host->mrq = NULL;
+	spin_unlock_irqrestore(&host->lock, flags);
+	mmc_request_done(host->mmc, mrq);
+
+	return IRQ_HANDLED;
+}
+
+static void meson_mmc_timeout(struct work_struct *work)
+{
+	struct meson_mmc_host *host = container_of(work,
+						   struct meson_mmc_host,
+						   timeout_work.work);
+	struct mmc_request *mrq = host->mrq;
+	unsigned long flags;
+	u32 irqc;
+
+	spin_lock_irqsave(&host->lock, flags);
+
+	if (host->state == STATE_IDLE) {
+		spin_unlock_irqrestore(&host->lock, flags);
+		return;
+	}
+
+	dev_err(mmc_dev(host->mmc), "Timeout on CMD%u\n", mrq->cmd->opcode);
+
+	host->state = STATE_TIMEOUT;
+
+	irqc = readl(host->base + SDIO_IRQC);
+	irqc &= ~REG_IRQC_ARC_CMD_INT;
+	writel(irqc, host->base + SDIO_IRQC);
+
+	mrq->cmd->error = -ETIMEDOUT;
+
+	host->state = STATE_IDLE;
+	host->mrq = NULL;
+	spin_unlock_irqrestore(&host->lock, flags);
+
+	mmc_request_done(host->mmc, mrq);
+}
+
+static void meson_mmc_reset(struct mmc_host *mmc)
+{
+	struct meson_mmc_host *host = mmc_priv(mmc);
+	u32 reg = 0;
+
+	dev_dbg(mmc_dev(mmc), "resetting mmc controller\n");
+
+	reg =  (2 << REG_CONF_WR_CRC_S);
+	reg |= (2 << REG_CONF_WR_NWR_S);
+	reg |= (3 << REG_CONF_M_END_S);
+	reg |= (39 << REG_CONF_ARGU_BITS_S);
+
+	reg |= CLK_DIV;
+	writel(reg, host->base + SDIO_CONF);
+
+	reg = readl(host->base + SDIO_IRQS);
+	reg |= (REG_IRQS_CMD_INT);
+	writel(reg, host->base + SDIO_IRQS);
+}
+
+static struct mmc_host_ops meson_mmc_ops = {
+	.request	 = meson_mmc_request,
+	.set_ios	 = meson_mmc_set_ios,
+	.get_cd		 = mmc_gpio_get_cd,
+};
+
+static int meson_mmc_probe(struct platform_device *pdev)
+{
+	struct mmc_host *mmc;
+	struct meson_mmc_host *host;
+	struct device_node *node = pdev->dev.of_node;
+	int ret, sdio_port;
+
+	mmc = mmc_alloc_host(sizeof(struct meson_mmc_host), &pdev->dev);
+	if (!mmc) {
+		dev_err(&pdev->dev, "mmc alloc host failed\n");
+		return -ENOMEM;
+	}
+
+	host = mmc_priv(mmc);
+	host->mmc = mmc;
+	spin_lock_init(&host->lock);
+
+	host->base = devm_ioremap_resource(&pdev->dev,
+				platform_get_resource(pdev, IORESOURCE_MEM, 0));
+	if (IS_ERR(host->base)) {
+		ret = PTR_ERR(host->base);
+		goto error_free_host;
+	}
+
+	host->irq = platform_get_irq(pdev, 0);
+	ret = devm_request_threaded_irq(&pdev->dev, host->irq, meson_mmc_irq,
+			meson_mmc_irq_thread, 0, "meson_mmc", host);
+	if (ret)
+		goto error_free_host;
+
+	host->clk_sdio = devm_clk_get(&pdev->dev, NULL);
+	if (IS_ERR(host->clk_sdio)) {
+		dev_err(&pdev->dev, "Could not get clk81 clock\n");
+		ret = PTR_ERR(host->clk_sdio);
+		goto error_free_host;
+	}
+
+	mmc->ops = &meson_mmc_ops;
+
+	/* we do not support scatter lists in hardware */
+	mmc->max_segs = 1;
+	mmc->max_req_size = SDIO_BOUNCE_REQ_SIZE;
+	mmc->max_seg_size = mmc->max_req_size;
+	mmc->max_blk_count = 256;
+	mmc->max_blk_size = mmc->max_req_size / mmc->max_blk_count;
+	mmc->f_min = 300000;
+	mmc->f_max = 50000000;
+	mmc->caps |= MMC_CAP_4_BIT_DATA;
+	mmc->caps |= MMC_CAP_MMC_HIGHSPEED | MMC_CAP_SD_HIGHSPEED;
+	mmc->ocr_avail = MMC_VDD_33_34;
+
+	INIT_DELAYED_WORK(&host->timeout_work, meson_mmc_timeout);
+	host->timeout = msecs_to_jiffies(2000);
+	host->port = 0;
+
+	if (!of_property_read_u32(node, "meson,sdio-port", &sdio_port))
+		host->port = sdio_port;
+
+	ret = mmc_of_parse(mmc);
+	if (ret)
+		goto error_free_host;
+
+	platform_set_drvdata(pdev, mmc);
+
+	meson_mmc_reset(mmc);
+	mmc_add_host(mmc);
+
+	dev_info(&pdev->dev, "base:0x%p irq:%u port:%u\n",
+		 host->base, host->irq, host->port);
+
+	return 0;
+
+error_free_host:
+	mmc_free_host(mmc);
+
+	return ret;
+}
+
+static int meson_mmc_remove(struct platform_device *pdev)
+{
+	struct mmc_host	*mmc = platform_get_drvdata(pdev);
+	struct meson_mmc_host *host = mmc_priv(mmc);
+
+	mmc_remove_host(mmc);
+	disable_irq(host->irq);
+
+	mmc_free_host(mmc);
+
+	cancel_delayed_work_sync(&host->timeout_work);
+
+	return 0;
+}
+
+static const struct of_device_id meson_mmc_of_match[] = {
+	{ .compatible = "amlogic,meson-mmc", },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, meson_mmc_of_match);
+
+static struct platform_driver meson_mmc_driver = {
+	.probe   = meson_mmc_probe,
+	.remove  = meson_mmc_remove,
+	.driver  = {
+		.name = DRIVER_NAME,
+		.of_match_table = of_match_ptr(meson_mmc_of_match),
+	},
+};
+
+module_platform_driver(meson_mmc_driver);
+
+MODULE_DESCRIPTION("Meson Secure Digital Host Driver");
+MODULE_AUTHOR("Carlo Caione <carlo@endlessm.com>");
+MODULE_LICENSE("GPL");