[PATCH 2/2] MMC: meson: inital support for GXBB platforms

[Kevin Hilman <khilman@baylibre.com>]

Initial support for the SD/eMMC controller in the Amlogic S905/GXBB
family of SoCs.

Currently working for the SD and eMMC interfaces, but not yet tested for
SDIO.

Tested external SD card and internal eMMC on meson-gxbb-p200 and
meson-gxbb-odroidc2.

TODO items:
- take full advantage of DMA-like descriptors instead of bounce buffer
- add SDIO support
---
 drivers/mmc/host/Kconfig      |   7 +
 drivers/mmc/host/Makefile     |   1 +
 drivers/mmc/host/meson-gxbb.c | 909 ++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 917 insertions(+)
 create mode 100644 drivers/mmc/host/meson-gxbb.c

diff --git a/drivers/mmc/host/Kconfig b/drivers/mmc/host/Kconfig
index 0aa484c10c0a..2363c0cee9cc 100644
--- a/drivers/mmc/host/Kconfig
+++ b/drivers/mmc/host/Kconfig
@@ -332,6 +332,13 @@ config MMC_SDHCI_IPROC
 
 	  If unsure, say N.
 
+config MMC_MESON_GXBB
+	tristate "Amlogic S905/GXBB SD/MMC Host Controller support"
+	depends on ARCH_MESON && MMC
+	help
+	  This selects support for the Amlogic SD/MMC Host Controller.
+	  If you have a controller with this interface, say Y here.
+
 config MMC_MOXART
 	tristate "MOXART SD/MMC Host Controller support"
 	depends on ARCH_MOXART && MMC
diff --git a/drivers/mmc/host/Makefile b/drivers/mmc/host/Makefile
index af918d261ff9..3e0de57f55b9 100644
--- a/drivers/mmc/host/Makefile
+++ b/drivers/mmc/host/Makefile
@@ -53,6 +53,7 @@ obj-$(CONFIG_MMC_JZ4740)	+= jz4740_mmc.o
 obj-$(CONFIG_MMC_VUB300)	+= vub300.o
 obj-$(CONFIG_MMC_USHC)		+= ushc.o
 obj-$(CONFIG_MMC_WMT)		+= wmt-sdmmc.o
+obj-$(CONFIG_MMC_MESON_GXBB)	+= meson-gxbb.o
 obj-$(CONFIG_MMC_MOXART)	+= moxart-mmc.o
 obj-$(CONFIG_MMC_SUNXI)		+= sunxi-mmc.o
 obj-$(CONFIG_MMC_USDHI6ROL0)	+= usdhi6rol0.o
diff --git a/drivers/mmc/host/meson-gxbb.c b/drivers/mmc/host/meson-gxbb.c
new file mode 100644
index 000000000000..ecf7b4d2d330
--- /dev/null
+++ b/drivers/mmc/host/meson-gxbb.c
@@ -0,0 +1,909 @@
+/*
+ * This file is provided under a dual BSD/GPLv2 license.  When using or
+ * redistributing this file, you may do so under either license.
+ *
+ * GPL LICENSE SUMMARY
+ *
+ * Copyright (c) 2016 BayLibre, SAS.
+ * Author: Kevin Hilman <khilman@baylibre.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ * The full GNU General Public License is included in this distribution
+ * in the file called COPYING.
+ *
+ * BSD LICENSE
+ *
+ * Copyright (c) 2016 BayLibre, SAS.
+ * Author: Kevin Hilman <khilman@baylibre.com>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ *   * Redistributions of source code must retain the above copyright
+ *     notice, this list of conditions and the following disclaimer.
+ *   * 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.
+ *   * Neither the name of Intel Corporation nor the names of its
+ *     contributors may be used to endorse or promote products derived
+ *     from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "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 COPYRIGHT
+ * OWNER OR CONTRIBUTORS 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 <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/init.h>
+#include <linux/device.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/ioport.h>
+#include <linux/regmap.h>
+#include <linux/spinlock.h>
+#include <linux/dma-mapping.h>
+#include <linux/mmc/host.h>
+#include <linux/mmc/mmc.h>
+#include <linux/mmc/sdio.h>
+#include <linux/mmc/slot-gpio.h>
+#include <linux/io.h>
+#include <linux/clk.h>
+#include <linux/clk-provider.h>
+
+#define DRIVER_NAME "meson-gxbb-mmc"
+
+#define SD_EMMC_CLOCK 0x0
+#define   CLK_DIV_SHIFT 0
+#define   CLK_DIV_WIDTH 6
+#define   CLK_DIV_MASK (0x3f << CLK_DIV_SHIFT)
+#define   CLK_DIV_MAX 63
+#define   CLK_SRC_SHIFT 6
+#define   CLK_SRC_WIDTH 2
+#define   CLK_SRC_MASK (0x3 << CLK_SRC_SHIFT)
+#define   CLK_SRC_XTAL 0   /* external crystal */
+#define   CLK_SRC_XTAL_RATE 24000000
+#define   CLK_SRC_PLL 1    /* FCLK_DIV2 */
+#define   CLK_SRC_PLL_RATE 1000000000
+#define   CLK_PHASE_SHIFT 8
+#define   CLK_PHASE_MASK (0x3 << CLK_PHASE_SHIFT)
+#define   CLK_PHASE_0 0
+#define   CLK_PHASE_90 1
+#define   CLK_PHASE_180 2
+#define   CLK_PHASE_270 3
+#define   CLK_ALWAYS_ON BIT(24)
+
+#define SD_EMMC_DElAY 0x4
+#define SD_EMMC_ADJUST 0x8
+#define SD_EMMC_CALOUT 0x10
+#define SD_EMMC_START 0x40
+#define   START_DESC_INIT BIT(0)
+#define   START_DESC_BUSY BIT(1)
+#define   START_DESC_ADDR_SHIFT 2
+#define   START_DESC_ADDR_MASK (~0x3)
+
+#define SD_EMMC_CFG 0x44
+#define   CFG_BUS_WIDTH_SHIFT 0
+#define   CFG_BUS_WIDTH_MASK (0x3 << CFG_BUS_WIDTH_SHIFT)
+#define   CFG_BUS_WIDTH_1 0x0
+#define   CFG_BUS_WIDTH_4 0x1
+#define   CFG_BUS_WIDTH_8 0x2
+#define   CFG_DDR BIT(2)
+#define   CFG_BLK_LEN_SHIFT 4
+#define   CFG_BLK_LEN_MASK (0xf << CFG_BLK_LEN_SHIFT)
+#define   CFG_RESP_TIMEOUT_SHIFT 8
+#define   CFG_RESP_TIMEOUT_MASK (0xf << CFG_RESP_TIMEOUT_SHIFT)
+#define   CFG_RC_CC_SHIFT 12
+#define   CFG_RC_CC_MASK (0xf << CFG_RC_CC_SHIFT)
+#define   CFG_STOP_CLOCK BIT(22)
+
+#define SD_EMMC_STATUS 0x48
+#define   STATUS_BUSY BIT(31)
+	
+#define SD_EMMC_IRQ_EN 0x4c
+#define   IRQ_EN_MASK 0x3fff
+#define   IRQ_RXD_ERR_SHIFT 0
+#define   IRQ_RXD_ERR_MASK 0xff	
+#define   IRQ_TXD_ERR BIT(8)
+#define   IRQ_DESC_ERR BIT(9)
+#define   IRQ_RESP_ERR BIT(10)
+#define   IRQ_RESP_TIMEOUT BIT(11)
+#define   IRQ_DESC_TIMEOUT BIT(12)
+#define   IRQ_END_OF_CHAIN BIT(13)
+#define   IRQ_RESP_STATUS BIT(14)
+#define   IRQ_SDIO BIT(15)
+
+#define SD_EMMC_CMD_CFG 0x50
+#define SD_EMMC_CMD_ARG 0x54
+#define SD_EMMC_CMD_DAT 0x58
+#define SD_EMMC_CMD_RSP 0x5c
+#define SD_EMMC_CMD_RSP1 0x60
+#define SD_EMMC_CMD_RSP2 0x64
+#define SD_EMMC_CMD_RSP3 0x68
+
+#define SD_EMMC_RXD 0x94
+#define SD_EMMC_TXD 0x94
+#define SD_EMMC_LAST_REG SD_EMMC_TXD
+
+#define SD_EMMC_CFG_BLK_SIZE 512 /* internal buffer max: 512 bytes */
+#define SD_EMMC_CFG_RESP_TIMEOUT 256 /* in clock cycles */
+#define SD_EMMC_CFG_CMD_GAP 16 /* in clock cycles */
+#define MUX_CLK_NUM_PARENTS 2
+
+struct meson_host {
+	struct	device		*dev;
+	struct	mmc_host	*mmc;
+	struct	mmc_request	*mrq;
+	struct	mmc_command	*cmd;
+
+	spinlock_t lock;
+	void __iomem *regs;
+#ifdef USE_REGMAP
+	struct regmap *regmap;
+#endif
+	int irq;
+	u32 ocr_mask;
+	struct clk *core_clk;
+	struct clk_mux mux;
+	struct clk *mux_clk;
+	struct clk *mux_parent[MUX_CLK_NUM_PARENTS];
+	unsigned long mux_parent_rate[MUX_CLK_NUM_PARENTS];
+
+	struct clk_divider cfg_div;
+	struct clk *cfg_div_clk;
+	
+	unsigned int bounce_buf_size;
+	void *bounce_buf;
+	dma_addr_t bounce_dma_addr;
+
+	unsigned long clk_rate;
+	unsigned long clk_src_rate;
+	unsigned short clk_src_div;
+};
+
+#define reg_read(host, offset) readl(host->regs + offset)
+#define reg_write(host, offset, val) writel(val, host->regs + offset)
+
+struct cmd_cfg {
+	union {
+		struct {
+			u32 length:9;
+			u32 block_mode:1;
+			u32 r1b:1;
+			u32 end_of_chain:1;
+			u32 timeout:4;
+			u32 no_resp:1;
+			u32 no_cmd:1;
+			u32 data_io:1;
+			u32 data_wr:1;
+			u32 resp_nocrc:1;
+			u32 resp_128:1;
+			u32 resp_num:1;
+			u32 data_num:1;
+			u32 cmd_index:6;
+			u32 error:1;
+			u32 owner:1;
+#define CFG_OWNER_CPU 1
+#define CFG_OWNER_MMC 0	
+		};
+		u32 val;
+	};
+};
+
+struct sd_emmc_desc {
+	struct cmd_cfg cmd_cfg;
+	u32 cmd_arg;
+	u32 cmd_data;
+	u32 cmd_resp;
+};
+#define CMD_DATA_MASK (~0x3)
+#define CMD_DATA_BIG_ENDIAN BIT(1)
+#define CMD_DATA_SRAM BIT(0)
+#define CMD_RESP_MASK (~0x1)
+#define CMD_RESP_SRAM BIT(0)
+
+static int meson_mmc_clk_set(struct meson_host *host, unsigned long clk_rate)
+{
+	struct mmc_host *mmc = host->mmc;
+	int ret = 0;
+	u32 cfg;
+
+	if (clk_rate) {
+		if (WARN_ON(clk_rate > mmc->f_max))
+			clk_rate = mmc->f_max;
+		else if (WARN_ON(clk_rate < mmc->f_min))
+			clk_rate = mmc->f_min;
+	}
+	
+	if (clk_rate == host->clk_rate)
+		return 0;
+	
+	/* stop clock */
+	cfg = reg_read(host, SD_EMMC_CFG);
+	if (!(cfg & CFG_STOP_CLOCK)) {
+		cfg |= CFG_STOP_CLOCK;
+		reg_write(host, SD_EMMC_CFG, cfg);
+	}
+	
+	dev_dbg(host->dev, "change clock rate %lu -> %lu\n", host->clk_rate, clk_rate);
+	ret = clk_set_rate(host->cfg_div_clk, clk_rate);
+	if (clk_rate && clk_rate != clk_get_rate(host->cfg_div_clk))
+		dev_warn(host->dev, "divider requested rate %lu != actual rate %lu: ret=%d\n",
+			 clk_rate, clk_get_rate(host->cfg_div_clk), ret);
+	else
+		host->clk_rate = clk_rate;
+
+	/* (re)start clock, if non-zero */
+	if (clk_rate) {
+		cfg = reg_read(host, SD_EMMC_CFG);
+		cfg &= ~CFG_STOP_CLOCK;
+		reg_write(host, SD_EMMC_CFG, cfg);
+	}
+	
+	return ret;
+}
+
+static int meson_mmc_clk_init(struct meson_host *host)
+{
+	struct clk_init_data init;
+	char clk_name[32];
+	int i, ret = 0;
+	const char *mux_parent_names[MUX_CLK_NUM_PARENTS];
+	unsigned int mux_parent_count = 0;
+	const char *clk_div_parents[1];
+	unsigned int f_min = UINT_MAX;
+	u32 clk_reg;
+
+	/* get the mux parents from DT */
+	for ( i = 0; i < MUX_CLK_NUM_PARENTS; i++) {
+		char name[16];
+		
+		snprintf(name, sizeof(name), "clkin%d", i);
+		host->mux_parent[i] = devm_clk_get(host->dev, name);
+		if (IS_ERR(host->mux_parent[i])) {
+			ret = PTR_ERR(host->mux_parent[i]);
+			if (PTR_ERR(host->mux_parent[i]) != -EPROBE_DEFER)
+				dev_err(host->dev, "Missing clock %s\n", name);
+			host->mux_parent[i] = NULL;
+			return ret;
+		} else {
+			host->mux_parent_rate[i] = clk_get_rate(host->mux_parent[i]);
+			mux_parent_names[i] = __clk_get_name(host->mux_parent[i]);
+			mux_parent_count++;
+			if (host->mux_parent_rate[i] < f_min)
+				f_min = host->mux_parent_rate[i];
+		}
+	}
+
+	/* cacluate f_min based on available input clocks, and max divider value */
+	if (f_min != UINT_MAX)
+		f_min = DIV_ROUND_UP(CLK_SRC_XTAL_RATE, CLK_DIV_MAX);
+	else
+		f_min = 4000000;  /* default min: 400 MHz */
+	host->mmc->f_min = f_min;
+	
+	/* create the mux */
+	snprintf(clk_name, sizeof(clk_name), "%s#mux", dev_name(host->dev));
+	init.name = clk_name;
+	init.ops = &clk_mux_ops;
+	init.flags = CLK_IS_BASIC;
+	init.parent_names = mux_parent_names;
+	init.num_parents = mux_parent_count;
+	
+	host->mux.reg = host->regs + SD_EMMC_CLOCK;
+	host->mux.shift = CLK_SRC_SHIFT;
+	host->mux.mask = CLK_SRC_MASK >> CLK_SRC_SHIFT;  /* FIXME: fix *_MASK to not be shifted */
+	host->mux.flags = 0;
+	host->mux.table = NULL;
+	host->mux.hw.init = &init;
+		
+	host->mux_clk = devm_clk_register(host->dev, &host->mux.hw);
+	if (WARN_ON(PTR_ERR_OR_ZERO(host->mux_clk)))
+		return PTR_ERR(host->mux_clk);
+	
+	/* create the divider */
+	snprintf(clk_name, sizeof(clk_name), "%s#div", dev_name(host->dev));
+	init.name = devm_kstrdup(host->dev, clk_name, GFP_KERNEL);
+	init.ops = &clk_divider_ops;
+	init.flags = CLK_IS_BASIC | CLK_SET_RATE_PARENT;
+	clk_div_parents[0] = __clk_get_name(host->mux_clk);
+	init.parent_names = clk_div_parents;
+	init.num_parents = ARRAY_SIZE(clk_div_parents);
+
+	host->cfg_div.reg = host->regs + SD_EMMC_CLOCK;
+	host->cfg_div.shift = CLK_DIV_SHIFT;
+	host->cfg_div.width = CLK_DIV_WIDTH;
+	host->cfg_div.hw.init = &init;
+	host->cfg_div.flags = CLK_DIVIDER_ONE_BASED | CLK_DIVIDER_ROUND_CLOSEST | CLK_DIVIDER_ALLOW_ZERO;
+
+	host->cfg_div_clk = devm_clk_register(host->dev, &host->cfg_div.hw);
+	if (WARN_ON(PTR_ERR_OR_ZERO(host->cfg_div_clk)))
+		return PTR_ERR(host->cfg_div_clk);
+	
+	/* init SD_EMMC_CLOCK to sane defaults w/min clock rate */
+	clk_reg = 0;
+	clk_reg |= CLK_PHASE_180 << CLK_PHASE_SHIFT;
+	clk_reg |= CLK_SRC_XTAL << CLK_SRC_SHIFT;
+	clk_reg |= CLK_DIV_MAX << CLK_DIV_SHIFT;
+	reg_write(host, SD_EMMC_CLOCK, clk_reg);
+	
+	clk_prepare_enable(host->cfg_div_clk);
+	meson_mmc_clk_set(host, f_min);
+
+	return ret;
+}
+
+static void meson_mmc_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
+{
+	struct meson_host *host = mmc_priv(mmc);
+	u32 bus_width;
+	u32 val, orig;
+	
+	/* 
+	 * GPIO regulator, only controls switching between 1v8 and 3v3, doesn't support
+	 * MMC_POWER_OFF, MMC_POWER_ON.
+	 */	 
+	switch (ios->power_mode) {
+	case MMC_POWER_UP:
+		if (!IS_ERR(mmc->supply.vmmc))
+			mmc_regulator_set_ocr(mmc, mmc->supply.vmmc, ios->vdd);
+	}
+
+	meson_mmc_clk_set(host, ios->clock);
+
+	/* Bus width */
+	val = reg_read(host, SD_EMMC_CFG);
+	switch (ios->bus_width) {
+	case MMC_BUS_WIDTH_1:
+		bus_width = CFG_BUS_WIDTH_1;
+		break;
+	case MMC_BUS_WIDTH_4:
+		bus_width = CFG_BUS_WIDTH_4;
+		break;
+	case MMC_BUS_WIDTH_8:
+		bus_width = CFG_BUS_WIDTH_8;
+		break;
+	default:
+		dev_err(host->dev, "Invalid ios->bus_width: %u.  Setting to 4.\n", ios->bus_width);
+		bus_width = CFG_BUS_WIDTH_4;
+		return;
+	}
+
+	val = reg_read(host, SD_EMMC_CFG);
+	orig = val;
+
+	val &= ~CFG_BUS_WIDTH_MASK;
+	val |= bus_width << CFG_BUS_WIDTH_SHIFT;
+
+	val &= ~CFG_BLK_LEN_MASK;
+	val |= ilog2(SD_EMMC_CFG_BLK_SIZE) << CFG_BLK_LEN_SHIFT;
+
+	val &= ~CFG_RESP_TIMEOUT_MASK;
+	val |= ilog2(SD_EMMC_CFG_RESP_TIMEOUT) << CFG_RESP_TIMEOUT_SHIFT;
+	
+	val &= ~CFG_RC_CC_MASK;
+	val |= ilog2(SD_EMMC_CFG_CMD_GAP) << CFG_RC_CC_SHIFT;
+	
+	reg_write(host, SD_EMMC_CFG, val);
+
+	if (val != orig)
+		dev_dbg(host->dev, "%s: SD_EMMC_CFG: 0x%08x -> 0x%08x\n",
+			__func__, orig, val);
+
+	return;
+}
+
+static int meson_mmc_wait_busy(struct mmc_host *mmc, unsigned int timeout)
+{
+	struct meson_host *host = mmc_priv(mmc);
+	u32 status;
+	int i;
+	
+	for ( i = timeout; i > 0; i-- ) {
+		status = reg_read(host, SD_EMMC_STATUS);
+		if (!(status & STATUS_BUSY))
+			break;
+	};
+
+	return (timeout == 0);
+}
+
+static int meson_mmc_request_done(struct mmc_host *mmc, struct mmc_request *mrq)
+{
+	struct meson_host *host = mmc_priv(mmc);
+	struct mmc_command *cmd = host->cmd;
+	
+	WARN_ON(host->mrq != mrq);
+	if (cmd && !cmd->error)
+		if (meson_mmc_wait_busy(mmc, 0xfffff))  /* FIXME: hard-coded value */
+			dev_warn(host->dev, "%s: timeout busy.\n", __func__);
+
+	host->mrq = NULL;
+	host->cmd = NULL;
+	mmc_request_done(host->mmc, mrq);
+	
+	return 0;
+}
+
+static int meson_mmc_cmd_invalid(struct mmc_host *mmc, struct mmc_command *cmd)
+{
+	cmd->error = -EINVAL;
+	meson_mmc_request_done(mmc, cmd->mrq);
+
+	return -EINVAL;
+}
+
+static int meson_mmc_check_command(struct mmc_host *mmc, struct mmc_command *cmd)
+{
+	int ret = 0;
+	
+        if (true) {  /* FIXME: for SD card only */
+		if (cmd->opcode == SD_IO_SEND_OP_COND
+		    || cmd->opcode == SD_IO_RW_DIRECT
+		    || cmd->opcode == SD_IO_RW_EXTENDED) {
+			ret = meson_mmc_cmd_invalid(mmc, cmd);
+		}
+	}
+
+	return ret;
+}
+
+static void meson_mmc_start_cmd(struct mmc_host *mmc, struct mmc_command *cmd)
+{
+	struct meson_host *host = mmc_priv(mmc);
+	struct sd_emmc_desc *desc, desc_tmp;
+	u32 cfg;
+	u8 blk_len;
+	unsigned int xfer_bytes = 0;
+
+	/* Setup descriptors */
+	dma_rmb();
+	desc = &desc_tmp;
+	memset(desc, 0, sizeof(struct sd_emmc_desc));
+
+	desc->cmd_cfg.cmd_index = cmd->opcode;
+	desc->cmd_cfg.owner = CFG_OWNER_CPU;
+	desc->cmd_arg = cmd->arg;
+	/* FIXME: hard-coded timeouts from vendor BSP */
+        if (!cmd->data)
+                /* 10uS based. 2^10 = 10mS for only cmd timeout */
+		desc->cmd_cfg.timeout = 0xa;
+	else
+		desc->cmd_cfg.timeout = 0xc;
+
+	/* Response */
+        if (cmd->flags & MMC_RSP_PRESENT) {
+		desc->cmd_cfg.no_resp = 0;
+                if (cmd->flags & MMC_RSP_136)
+			desc->cmd_cfg.resp_128 = 1;
+		desc->cmd_cfg.resp_num = 1;
+		desc->cmd_resp = 0;
+
+		if (!(cmd->flags & MMC_RSP_CRC))
+			desc->cmd_cfg.resp_nocrc = 1;
+		
+		if (cmd->flags & MMC_RSP_BUSY)
+			desc->cmd_cfg.r1b = 1;
+	} else {
+		desc->cmd_cfg.no_resp = 1;
+	}
+
+	/* data? */
+        if (cmd->data) {
+		desc->cmd_cfg.data_io = 1;
+		if (cmd->data->blocks > 1) {
+			desc->cmd_cfg.block_mode = 1;
+			desc->cmd_cfg.length = cmd->data->blocks;
+
+			/* check if block-size matches, if not update */
+			cfg = reg_read(host, SD_EMMC_CFG);
+			blk_len = (cfg & CFG_BLK_LEN_MASK) >> CFG_BLK_LEN_SHIFT;
+			if (blk_len != ilog2(cmd->data->blksz)) {
+				dev_warn(host->dev, "%s: update blk_len %d -> %d\n",
+					__func__, blk_len, ilog2(cmd->data->blksz));
+				blk_len = ilog2(cmd->data->blksz);
+				cfg &= ~CFG_BLK_LEN_MASK;
+				cfg |= blk_len << CFG_BLK_LEN_SHIFT;
+				reg_write(host, SD_EMMC_CFG, cfg);
+			}
+		} else {
+			desc->cmd_cfg.block_mode = 0;
+			desc->cmd_cfg.length = cmd->data->blksz;
+		}
+
+		cmd->data->bytes_xfered = 0;
+		xfer_bytes = cmd->data->blksz * cmd->data->blocks;
+		/* dev_dbg(host->dev, "%s: sg_len=%u, %s %u bytes\n", __func__, */
+		/* 	cmd->data->sg_len, cmd->data->flags & MMC_DATA_WRITE ? "WRITE" : "READ", xfer_bytes); */
+		if (cmd->data->flags & MMC_DATA_WRITE) {
+			desc->cmd_cfg.data_wr = 1;
+			WARN_ON(xfer_bytes > host->bounce_buf_size);
+			sg_copy_to_buffer(cmd->data->sg, cmd->data->sg_len, host->bounce_buf, xfer_bytes);
+			cmd->data->bytes_xfered = xfer_bytes;
+			dma_wmb();
+		} else {
+			desc->cmd_cfg.data_wr = 0;
+		}
+
+		if (xfer_bytes > 0) {
+			desc->cmd_cfg.data_num = 0;
+			desc->cmd_data = host->bounce_dma_addr & CMD_DATA_MASK;
+		} else {
+			/* write data to data_addr */
+			desc->cmd_cfg.data_num = 1;
+			desc->cmd_data = 0;
+		}
+
+	} else {
+		desc->cmd_cfg.data_io = 0;
+
+                /* Current 10uS based. 2^10 = 10mS for only cmd timeout */
+		desc->cmd_cfg.timeout = 0xa;
+	}
+	
+	host->cmd = cmd;
+
+	/* Last descriptor */
+	desc->cmd_cfg.end_of_chain = 1;
+	reg_write(host, SD_EMMC_CMD_CFG, desc->cmd_cfg.val);
+	reg_write(host, SD_EMMC_CMD_DAT, desc->cmd_data);
+	reg_write(host, SD_EMMC_CMD_RSP, desc->cmd_resp);
+	wmb();
+	reg_write(host, SD_EMMC_CMD_ARG, desc->cmd_arg);  /* this triggers the cmd */
+}
+
+static void meson_mmc_request(struct mmc_host *mmc, struct mmc_request *mrq)
+{
+	struct meson_host *host = mmc_priv(mmc);
+	
+	WARN_ON(host->mrq != NULL);
+
+	/* Stop execution */
+	reg_write(host, SD_EMMC_START, 0);
+
+	/* clear, ack, enable all interrupts */
+	reg_write(host, SD_EMMC_IRQ_EN, 0);
+	reg_write(host, SD_EMMC_STATUS, IRQ_EN_MASK);
+	reg_write(host, SD_EMMC_IRQ_EN, IRQ_EN_MASK);
+
+	host->mrq = mrq;
+	
+	if (meson_mmc_check_command(mmc, mrq->cmd))
+		return;
+	
+	if (mrq->sbc)
+		meson_mmc_start_cmd(mmc, mrq->sbc);
+	else
+		meson_mmc_start_cmd(mmc, mrq->cmd);
+
+	return;
+}
+
+static int meson_mmc_read_response(struct mmc_host *mmc, struct mmc_command *cmd)
+{
+	struct meson_host *host = mmc_priv(mmc);
+	
+	if (!cmd) {
+		dev_dbg(host->dev, "%s: NULL command.\n", __func__);
+		return -EINVAL;
+	}
+
+	if (cmd->flags & MMC_RSP_136) {
+		cmd->resp[0] = reg_read(host, SD_EMMC_CMD_RSP3);
+		cmd->resp[1] = reg_read(host, SD_EMMC_CMD_RSP2);
+		cmd->resp[2] = reg_read(host, SD_EMMC_CMD_RSP1);
+		cmd->resp[3] = reg_read(host, SD_EMMC_CMD_RSP);
+	} else if (cmd->flags & MMC_RSP_PRESENT) {
+		cmd->resp[0] = reg_read(host, SD_EMMC_CMD_RSP);
+	}
+	
+	return 0;
+}
+
+static irqreturn_t meson_mmc_irq(int irq, void *dev_id)
+{
+	struct meson_host *host = dev_id;
+	struct mmc_request *mrq = host->mrq;
+	struct mmc_command *cmd = host->cmd;
+	u32 irq_en, status, raw_status;
+	irqreturn_t ret = IRQ_HANDLED;
+	
+	if (WARN_ON(!host))
+		return IRQ_NONE;
+
+	if (WARN_ON(!mrq))
+		return IRQ_NONE;
+
+	if (WARN_ON(!cmd))
+		return IRQ_NONE;
+
+	spin_lock(&host->lock);
+	irq_en = reg_read(host, SD_EMMC_IRQ_EN);
+	raw_status = reg_read(host, SD_EMMC_STATUS);
+	status = raw_status & irq_en;
+
+	if (!status) {
+		dev_warn(host->dev, "Spurious IRQ! status=0x%08x, irq_en=0x%08x\n",
+			 raw_status, irq_en);
+		ret = IRQ_NONE;
+		goto out;
+	}
+
+	cmd->error = 0;
+	if (status & IRQ_RXD_ERR_MASK) {
+		dev_dbg(host->dev, "Unhandled IRQ: RXD error\n");
+		cmd->error = -EILSEQ;
+	}
+	if (status & IRQ_TXD_ERR) {
+		dev_dbg(host->dev, "Unhandled IRQ: TXD error\n");
+		cmd->error = -EILSEQ;
+	}
+	if (status & IRQ_DESC_ERR)
+		dev_dbg(host->dev, "Unhandled IRQ: Descriptor error\n");
+	if (status & IRQ_RESP_ERR) {
+		dev_dbg(host->dev, "Unhandled IRQ: Response error\n");
+		cmd->error = -EILSEQ;
+	}
+	if (status & IRQ_RESP_TIMEOUT) {
+		dev_dbg(host->dev, "Unhandled IRQ: Response timeout\n");
+		cmd->error = -ETIMEDOUT;
+	}
+	if (status & IRQ_DESC_TIMEOUT) {
+		dev_dbg(host->dev, "Unhandled IRQ: Descriptor timeout\n");
+		cmd->error = -ETIMEDOUT;
+	}
+	if (status & IRQ_SDIO)
+		dev_dbg(host->dev, "Unhandled IRQ: SDIO.\n");
+
+	if (status & (IRQ_END_OF_CHAIN | IRQ_RESP_STATUS))
+		ret = IRQ_WAKE_THREAD;
+	else  {
+		dev_warn(host->dev, "Unknown IRQ! status=0x%04x: MMC CMD%u arg=0x%08x flags=0x%08x stop=%d\n",
+			 status, cmd->opcode, cmd->arg, cmd->flags, mrq->stop ? 1 : 0);
+		if (cmd->data) {
+			struct mmc_data *data = cmd->data;
+			dev_warn(host->dev, "\tblksz %u blocks %u flags 0x%08x (%s%s)", data->blksz, data->blocks, data->flags,
+				 data->flags & MMC_DATA_WRITE ? "write" : "",
+				 data->flags & MMC_DATA_READ ? "read" : "");
+		}
+	}
+	
+out:
+	/* ack all (enabled) interrupts */
+	reg_write(host, SD_EMMC_STATUS, status);
+
+	if (ret == IRQ_HANDLED) {
+		meson_mmc_read_response(host->mmc, cmd);
+		meson_mmc_request_done(host->mmc, cmd->mrq);
+	}
+
+	spin_unlock(&host->lock);
+       	return ret;
+}
+
+static irqreturn_t meson_mmc_irq_thread(int irq, void *dev_id)
+{
+	struct meson_host *host = dev_id;
+	struct mmc_request *mrq = host->mrq;
+	struct mmc_command *cmd = host->cmd;
+	struct mmc_data *data;
+	
+	unsigned int xfer_bytes;
+	int ret = IRQ_HANDLED;
+	
+	if (WARN_ON(!mrq))
+		ret = IRQ_NONE;
+
+	if (WARN_ON(!cmd))
+		ret = IRQ_NONE;
+
+	data = cmd->data;
+	if (data) {
+		xfer_bytes = data->blksz * data->blocks;
+		if (data->flags & MMC_DATA_READ) {
+			WARN_ON(xfer_bytes > host->bounce_buf_size);
+			sg_copy_from_buffer(data->sg, data->sg_len,
+					    host->bounce_buf, xfer_bytes);
+			data->bytes_xfered = xfer_bytes;
+		}
+	}
+		
+	meson_mmc_read_response(host->mmc, cmd);
+	if (!data || !data->stop || mrq->sbc)
+		meson_mmc_request_done(host->mmc, mrq);
+	else
+		meson_mmc_start_cmd(host->mmc, data->stop);
+	
+	return ret;
+}
+
+/* 
+ * NOTE: we only need this until the GPIO/pinctrl driver can handle
+ * interrupts.  For now, the MMC core will use this for polling.
+ */
+static int meson_mmc_get_cd(struct mmc_host *mmc)
+{
+	int status = mmc_gpio_get_cd(mmc);
+	
+	if (status == -ENOSYS)
+		return 1; /* assume present */
+	
+	return status;
+}
+
+static struct mmc_host_ops meson_mmc_ops = {
+	.request	= meson_mmc_request,
+	.set_ios	= meson_mmc_set_ios,
+	.get_cd         = meson_mmc_get_cd,
+};
+
+static int meson_mmc_probe(struct platform_device *pdev)
+{
+	struct device_node *np = pdev->dev.of_node;
+	struct resource *res;
+	struct meson_host *host;
+	struct mmc_host *mmc;
+	int ret;
+	
+	mmc = mmc_alloc_host(sizeof(struct meson_host), &pdev->dev);
+	if (!mmc)
+		return -ENOMEM;
+	host = mmc_priv(mmc);
+	host->mmc = mmc;
+	host->dev = &pdev->dev;
+	dev_set_drvdata(&pdev->dev, host);
+	
+	spin_lock_init(&host->lock);
+	
+	host->core_clk = devm_clk_get(&pdev->dev, "core");
+	if (IS_ERR(host->core_clk)) {
+		ret = PTR_ERR(host->core_clk);
+		if (ret == -EPROBE_DEFER)
+			dev_dbg(&pdev->dev, "Missing core clock.  EPROBE_DEFER\n");
+		else
+			dev_err(&pdev->dev, "Unable to get core clk (ret=%d).\n", ret);
+		goto free_host;
+	}
+
+	/* Voltage supply */
+	mmc_of_parse_voltage(np, &host->ocr_mask);
+	ret = mmc_regulator_get_supply(mmc);
+	if (ret == -EPROBE_DEFER) {
+		dev_dbg(&pdev->dev, "Missing regulator: EPROBE_DEFER");
+		goto free_host;
+	}
+	
+	if (!mmc->ocr_avail)
+		mmc->ocr_avail = host->ocr_mask;
+	
+	ret = mmc_of_parse(mmc);
+	if (ret) {
+		dev_warn(&pdev->dev, "error parsing DT: %d\n", ret);
+		goto free_host;
+	}
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res) {
+		ret = -ENODEV; 
+		goto free_host;
+	}
+	host->regs = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(host->regs)) {
+		ret = PTR_ERR(host->regs);
+		goto free_host;
+	}
+	
+	host->irq = platform_get_irq(pdev, 0);
+	if (host->irq == 0) {
+		dev_err(&pdev->dev, "failed to get interrupt resource.\n");
+		ret = -EINVAL;
+		goto free_host;
+	}
+
+	ret = devm_request_threaded_irq(&pdev->dev, host->irq,
+					meson_mmc_irq, meson_mmc_irq_thread,
+					IRQF_SHARED, DRIVER_NAME, host);
+	if (ret)
+		goto free_host;
+	
+	/* data bounce buffer */
+	host->bounce_buf_size = SZ_512K;
+	host->bounce_buf = dma_alloc_coherent(host->dev, host->bounce_buf_size,
+					      &host->bounce_dma_addr, GFP_KERNEL);
+	if (host->bounce_buf == NULL) {
+		dev_err(host->dev, "Unable to map allocate DMA bounce buffer.\n");
+		ret = -ENOMEM;
+		goto free_host;
+	}
+
+	clk_prepare_enable(host->core_clk);
+
+	ret = meson_mmc_clk_init(host);
+	if (ret)
+		goto free_host;
+
+	/* Stop execution */
+	reg_write(host, SD_EMMC_START, 0);
+
+	/* clear, ack, enable all interrupts */
+	reg_write(host, SD_EMMC_IRQ_EN, 0);
+	reg_write(host, SD_EMMC_STATUS, IRQ_EN_MASK);
+	
+	mmc->ops = &meson_mmc_ops;
+	mmc_add_host(mmc);
+
+	return 0;
+
+free_host:
+	dev_dbg(host->dev, "Failed to probe: ret=%d\n", ret);
+	if (host->core_clk)
+		clk_disable_unprepare(host->core_clk);
+	mmc_free_host(mmc);
+	return ret;
+}
+
+static int meson_mmc_remove(struct platform_device *pdev)
+{
+	struct meson_host *host = dev_get_drvdata(&pdev->dev);
+	
+	if (WARN_ON(!host))
+		return 0;
+	
+	if (host->bounce_buf)
+		dma_free_coherent(host->dev, host->bounce_buf_size,
+				  host->bounce_buf, host->bounce_dma_addr);
+
+	if (host->cfg_div_clk)
+		clk_disable_unprepare(host->cfg_div_clk);
+	
+	if (host->core_clk)
+		clk_disable_unprepare(host->core_clk);
+
+	mmc_free_host(host->mmc);
+	return 0;
+}
+
+static const struct of_device_id meson_mmc_of_match[] = {
+	{
+		.compatible = "amlogic,meson-gxbb-mmc",
+	},
+	{}
+};
+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_ALIAS("platform:" DRIVER_NAME);
+MODULE_DESCRIPTION("Amlogic S905/GXBB SD/eMMC driver");
+MODULE_AUTHOR("Kevin Hilman <khilman@baylibre.com>");
+MODULE_LICENSE("Dual BSD/GPL");
+
-- 
2.9.0