[v3,4/6] mmc: uniphier-sd: add UniPhier SD/eMMC controller driver

Message ID 1534999460-15111-5-git-send-email-yamada.masahiro@socionext.com
State New
Headers show
Series
  • [v3,1/6] mmc: tmio: replace tmio_mmc_clk_stop() calls with tmio_mmc_set_clock()
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Commit Message

Masahiro Yamada Aug. 23, 2018, 4:44 a.m.
Here is another TMIO MMC variant found in Socionext UniPhier SoCs.

As commit b6147490e6aa ("mmc: tmio: split core functionality, DMA and
MFD glue") said, these MMC controllers use the IP from Panasonic.

However, the MMC controller in the TMIO (Toshiba Mobile IO) MFD chip
was the first upstreamed user of this IP.  The common driver code
for this IP is now called 'tmio-mmc-core' in Linux although it is a
historical misnomer.

Anyway, this driver select's MMC_TMIO_CORE to borrow the common code
from tmio-mmc-core.c

Older UniPhier SoCs (LD4, Pro4, sLD8) support the external DMA engine
like renesas_sdhi_sys_dmac.c.  The difference is UniPhier SoCs use a
single DMA channel whereas Renesas chips request separate channels for
RX and TX.

Newer UniPhier SoCs (Pro5 and later) support the internal DMA engine
like renesas_sdhi_internal_dmac.c  The register map is almost the same,
so I guess Renesas and Socionext use the same internal DMA hardware.
The main difference is, the register offsets are doubled for Renesas.

                        Renesas      Socionext
                        SDHI         UniPhier
  DM_CM_DTRAN_MODE      0x820        0x410
  DM_CM_DTRAN_CTRL      0x828        0x414
  DM_CM_RST             0x830        0x418
  DM_CM_INFO1           0x840        0x420
  DM_CM_INFO1_MASK      0x848        0x424
  DM_CM_INFO2           0x850        0x428
  DM_CM_INFO2_MASK      0x858        0x42c
  DM_DTRAN_ADDR         0x880        0x440
  DM_DTRAN_ADDREX        ---         0x444

This comes from the difference of host->bus_shift; 2 for Renesas SoCs,
and 1 for UniPhier SoCs.  Also, the datasheet for UniPhier SoCs defines
DM_DTRAN_ADDR and DM_DTRAN_ADDREX as two separate registers.

It could be possible to factor out the DMA common code by introducing
some hooks to cope with platform quirks, but this patch does not touch
that for now.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

Acked-by: Wolfram Sang <wsa+renesas@sang-engineering.com>

---

Changes in v3:
  - Fix double dma_unmap_sg for external dma engine
  - Add error status handling for DMA callback-result

Changes in v2:
  - Rename compatible "socionext,uniphier-sd-v3.1b"
    to "socionext,uniphier-sd-v3.1.1"
  - Use ->callback_result hook instead of deprecated ->callback

 MAINTAINERS                    |   1 +
 drivers/mmc/host/Kconfig       |  10 +
 drivers/mmc/host/Makefile      |   1 +
 drivers/mmc/host/uniphier-sd.c | 693 +++++++++++++++++++++++++++++++++++++++++
 4 files changed, 705 insertions(+)
 create mode 100644 drivers/mmc/host/uniphier-sd.c

-- 
2.7.4

Comments

Masahiro Yamada Aug. 24, 2018, 1:50 a.m. | #1
2018-08-23 19:43 GMT+09:00 Ulf Hansson <ulf.hansson@linaro.org>:
> [...]

>

>> +static void uniphier_sd_external_dma_request(struct tmio_mmc_host *host,

>> +                                            struct tmio_mmc_data *pdata)

>> +{

>> +       struct uniphier_sd_priv *priv = uniphier_sd_priv(host);

>> +       struct dma_chan *chan;

>> +

>> +       chan = dma_request_chan(mmc_dev(host->mmc), "rx-tx");

>> +       if (IS_ERR(chan)) {

>> +               dev_warn(mmc_dev(host->mmc),

>> +                        "failed to request DMA channel. falling back to PIO\n");

>> +               return; /* just use PIO even for -EPROBE_DEFER */

>> +       }

>> +

>> +       /* this driver uses a single channel for both RX an TX */

>> +       priv->chan = chan;

>> +       host->chan_rx = chan;

>> +       host->chan_tx = chan;

>> +

>> +       tasklet_init(&host->dma_issue, uniphier_sd_external_dma_issue,

>> +                    (unsigned long)host);

>

> Isn't it time to get rid of tasklets for tmio?

>

> No worries, I don't require that to be changed prior $subject patch,

> however using threaded IRQs is a justified modernization for the tmio

> variants.



Yeah, I also thought this.

But, the irq handler is in the TMIO common code,
so it would affect Renesas code.

tmio-mmc has lots to be improved.
Tasklet is not the only problem.


Before investing more effort,
I want working code base for my platform.


Anyway, thanks for applying this!



> [...]

>

> Kind regards

> Uffe




-- 
Best Regards
Masahiro Yamada
Ulf Hansson Aug. 24, 2018, 6:32 a.m. | #2
On 24 August 2018 at 03:50, Masahiro Yamada
<yamada.masahiro@socionext.com> wrote:
> 2018-08-23 19:43 GMT+09:00 Ulf Hansson <ulf.hansson@linaro.org>:

>> [...]

>>

>>> +static void uniphier_sd_external_dma_request(struct tmio_mmc_host *host,

>>> +                                            struct tmio_mmc_data *pdata)

>>> +{

>>> +       struct uniphier_sd_priv *priv = uniphier_sd_priv(host);

>>> +       struct dma_chan *chan;

>>> +

>>> +       chan = dma_request_chan(mmc_dev(host->mmc), "rx-tx");

>>> +       if (IS_ERR(chan)) {

>>> +               dev_warn(mmc_dev(host->mmc),

>>> +                        "failed to request DMA channel. falling back to PIO\n");

>>> +               return; /* just use PIO even for -EPROBE_DEFER */

>>> +       }

>>> +

>>> +       /* this driver uses a single channel for both RX an TX */

>>> +       priv->chan = chan;

>>> +       host->chan_rx = chan;

>>> +       host->chan_tx = chan;

>>> +

>>> +       tasklet_init(&host->dma_issue, uniphier_sd_external_dma_issue,

>>> +                    (unsigned long)host);

>>

>> Isn't it time to get rid of tasklets for tmio?

>>

>> No worries, I don't require that to be changed prior $subject patch,

>> however using threaded IRQs is a justified modernization for the tmio

>> variants.

>

>

> Yeah, I also thought this.

>

> But, the irq handler is in the TMIO common code,

> so it would affect Renesas code.


Yep.

>

> tmio-mmc has lots to be improved.

> Tasklet is not the only problem.


Sure.

>

>

> Before investing more effort,

> I want working code base for my platform.


Totally acceptable!

[...]

Kind regards
Uffe

Patch

diff --git a/MAINTAINERS b/MAINTAINERS
index efb08d7..fb36f44 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -2181,6 +2181,7 @@  F:	drivers/clk/uniphier/
 F:	drivers/gpio/gpio-uniphier.c
 F:	drivers/i2c/busses/i2c-uniphier*
 F:	drivers/irqchip/irq-uniphier-aidet.c
+F:	drivers/mmc/host/uniphier-sd.c
 F:	drivers/pinctrl/uniphier/
 F:	drivers/reset/reset-uniphier.c
 F:	drivers/tty/serial/8250/8250_uniphier.c
diff --git a/drivers/mmc/host/Kconfig b/drivers/mmc/host/Kconfig
index 4dfa67a..d2fe4ce 100644
--- a/drivers/mmc/host/Kconfig
+++ b/drivers/mmc/host/Kconfig
@@ -630,6 +630,16 @@  config MMC_SDHI_INTERNAL_DMAC
 	  using on-chip bus mastering. This supports the controllers
 	  found in arm64 based SoCs.
 
+config MMC_UNIPHIER
+	tristate "UniPhier SD/eMMC Host Controller support"
+	depends on ARCH_UNIPHIER || COMPILE_TEST
+	depends on OF
+	select MMC_TMIO_CORE
+	help
+	  This provides support for the SD/eMMC controller found in
+	  UniPhier SoCs. The eMMC variant of this controller is used
+	  only for 32-bit SoCs.
+
 config MMC_CB710
 	tristate "ENE CB710 MMC/SD Interface support"
 	depends on PCI
diff --git a/drivers/mmc/host/Makefile b/drivers/mmc/host/Makefile
index ce8398e..a835d1a 100644
--- a/drivers/mmc/host/Makefile
+++ b/drivers/mmc/host/Makefile
@@ -42,6 +42,7 @@  obj-$(CONFIG_MMC_TMIO_CORE)	+= tmio_mmc_core.o
 obj-$(CONFIG_MMC_SDHI)		+= renesas_sdhi_core.o
 obj-$(CONFIG_MMC_SDHI_SYS_DMAC)		+= renesas_sdhi_sys_dmac.o
 obj-$(CONFIG_MMC_SDHI_INTERNAL_DMAC)	+= renesas_sdhi_internal_dmac.o
+obj-$(CONFIG_MMC_UNIPHIER)	+= uniphier-sd.o
 obj-$(CONFIG_MMC_CB710)		+= cb710-mmc.o
 obj-$(CONFIG_MMC_VIA_SDMMC)	+= via-sdmmc.o
 octeon-mmc-objs := cavium.o cavium-octeon.o
diff --git a/drivers/mmc/host/uniphier-sd.c b/drivers/mmc/host/uniphier-sd.c
new file mode 100644
index 0000000..10e7b30
--- /dev/null
+++ b/drivers/mmc/host/uniphier-sd.c
@@ -0,0 +1,693 @@ 
+// SPDX-License-Identifier: GPL-2.0
+//
+// Copyright (C) 2017-2018 Socionext Inc.
+//   Author: Masahiro Yamada <yamada.masahiro@socionext.com>
+
+#include <linux/bitfield.h>
+#include <linux/bitops.h>
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/dma-mapping.h>
+#include <linux/mfd/tmio.h>
+#include <linux/mmc/host.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/pinctrl/consumer.h>
+#include <linux/platform_device.h>
+#include <linux/reset.h>
+
+#include "tmio_mmc.h"
+
+#define   UNIPHIER_SD_CLK_CTL_DIV1024		BIT(16)
+#define   UNIPHIER_SD_CLK_CTL_DIV1		BIT(10)
+#define   UNIPHIER_SD_CLKCTL_OFFEN		BIT(9)  // auto SDCLK stop
+#define UNIPHIER_SD_CC_EXT_MODE		0x1b0
+#define   UNIPHIER_SD_CC_EXT_MODE_DMA		BIT(1)
+#define UNIPHIER_SD_HOST_MODE		0x1c8
+#define UNIPHIER_SD_VOLT		0x1e4
+#define   UNIPHIER_SD_VOLT_MASK			GENMASK(1, 0)
+#define   UNIPHIER_SD_VOLT_OFF			0
+#define   UNIPHIER_SD_VOLT_330			1	// 3.3V signal
+#define   UNIPHIER_SD_VOLT_180			2	// 1.8V signal
+#define UNIPHIER_SD_DMA_MODE		0x410
+#define   UNIPHIER_SD_DMA_MODE_DIR_MASK		GENMASK(17, 16)
+#define   UNIPHIER_SD_DMA_MODE_DIR_TO_DEV	0
+#define   UNIPHIER_SD_DMA_MODE_DIR_FROM_DEV	1
+#define   UNIPHIER_SD_DMA_MODE_WIDTH_MASK	GENMASK(5, 4)
+#define   UNIPHIER_SD_DMA_MODE_WIDTH_8		0
+#define   UNIPHIER_SD_DMA_MODE_WIDTH_16		1
+#define   UNIPHIER_SD_DMA_MODE_WIDTH_32		2
+#define   UNIPHIER_SD_DMA_MODE_WIDTH_64		3
+#define   UNIPHIER_SD_DMA_MODE_ADDR_INC		BIT(0)	// 1: inc, 0: fixed
+#define UNIPHIER_SD_DMA_CTL		0x414
+#define   UNIPHIER_SD_DMA_CTL_START	BIT(0)	// start DMA (auto cleared)
+#define UNIPHIER_SD_DMA_RST		0x418
+#define   UNIPHIER_SD_DMA_RST_CH1	BIT(9)
+#define   UNIPHIER_SD_DMA_RST_CH0	BIT(8)
+#define UNIPHIER_SD_DMA_ADDR_L		0x440
+#define UNIPHIER_SD_DMA_ADDR_H		0x444
+
+/*
+ * IP is extended to support various features: built-in DMA engine,
+ * 1/1024 divisor, etc.
+ */
+#define UNIPHIER_SD_CAP_EXTENDED_IP		BIT(0)
+/* RX channel of the built-in DMA controller is broken (Pro5) */
+#define UNIPHIER_SD_CAP_BROKEN_DMA_RX		BIT(1)
+
+struct uniphier_sd_priv {
+	struct tmio_mmc_data tmio_data;
+	struct pinctrl *pinctrl;
+	struct pinctrl_state *pinstate_default;
+	struct pinctrl_state *pinstate_uhs;
+	struct clk *clk;
+	struct reset_control *rst;
+	struct reset_control *rst_br;
+	struct reset_control *rst_hw;
+	struct dma_chan *chan;
+	enum dma_data_direction dma_dir;
+	unsigned long clk_rate;
+	unsigned long caps;
+};
+
+static void *uniphier_sd_priv(struct tmio_mmc_host *host)
+{
+	return container_of(host->pdata, struct uniphier_sd_priv, tmio_data);
+}
+
+static void uniphier_sd_dma_endisable(struct tmio_mmc_host *host, int enable)
+{
+	sd_ctrl_write16(host, CTL_DMA_ENABLE, DMA_ENABLE_DMASDRW);
+}
+
+/* external DMA engine */
+static void uniphier_sd_external_dma_issue(unsigned long arg)
+{
+	struct tmio_mmc_host *host = (void *)arg;
+	struct uniphier_sd_priv *priv = uniphier_sd_priv(host);
+
+	uniphier_sd_dma_endisable(host, 1);
+	dma_async_issue_pending(priv->chan);
+}
+
+static void uniphier_sd_external_dma_callback(void *param,
+					const struct dmaengine_result *result)
+{
+	struct tmio_mmc_host *host = param;
+	struct uniphier_sd_priv *priv = uniphier_sd_priv(host);
+	unsigned long flags;
+
+	dma_unmap_sg(mmc_dev(host->mmc), host->sg_ptr, host->sg_len,
+		     priv->dma_dir);
+
+	spin_lock_irqsave(&host->lock, flags);
+
+	if (result->result == DMA_TRANS_NOERROR) {
+		/*
+		 * When the external DMA engine is enabled, strangely enough,
+		 * the DATAEND flag can be asserted even if the DMA engine has
+		 * not been kicked yet.  Enable the TMIO_STAT_DATAEND irq only
+		 * after we make sure the DMA engine finishes the transfer,
+		 * hence, in this callback.
+		 */
+		tmio_mmc_enable_mmc_irqs(host, TMIO_STAT_DATAEND);
+	} else {
+		host->data->error = -ETIMEDOUT;
+		tmio_mmc_do_data_irq(host);
+	}
+
+	spin_unlock_irqrestore(&host->lock, flags);
+}
+
+static void uniphier_sd_external_dma_start(struct tmio_mmc_host *host,
+					   struct mmc_data *data)
+{
+	struct uniphier_sd_priv *priv = uniphier_sd_priv(host);
+	enum dma_transfer_direction dma_tx_dir;
+	struct dma_async_tx_descriptor *desc;
+	dma_cookie_t cookie;
+	int sg_len;
+
+	if (!priv->chan)
+		goto force_pio;
+
+	if (data->flags & MMC_DATA_READ) {
+		priv->dma_dir = DMA_FROM_DEVICE;
+		dma_tx_dir = DMA_DEV_TO_MEM;
+	} else {
+		priv->dma_dir = DMA_TO_DEVICE;
+		dma_tx_dir = DMA_MEM_TO_DEV;
+	}
+
+	sg_len = dma_map_sg(mmc_dev(host->mmc), host->sg_ptr, host->sg_len,
+			    priv->dma_dir);
+	if (sg_len == 0)
+		goto force_pio;
+
+	desc = dmaengine_prep_slave_sg(priv->chan, host->sg_ptr, sg_len,
+				       dma_tx_dir, DMA_CTRL_ACK);
+	if (!desc)
+		goto unmap_sg;
+
+	desc->callback_result = uniphier_sd_external_dma_callback;
+	desc->callback_param = host;
+
+	cookie = dmaengine_submit(desc);
+	if (cookie < 0)
+		goto unmap_sg;
+
+	return;
+
+unmap_sg:
+	dma_unmap_sg(mmc_dev(host->mmc), host->sg_ptr, host->sg_len,
+		     priv->dma_dir);
+force_pio:
+	host->force_pio = true;
+	uniphier_sd_dma_endisable(host, 0);
+}
+
+static void uniphier_sd_external_dma_enable(struct tmio_mmc_host *host,
+					    bool enable)
+{
+}
+
+static void uniphier_sd_external_dma_request(struct tmio_mmc_host *host,
+					     struct tmio_mmc_data *pdata)
+{
+	struct uniphier_sd_priv *priv = uniphier_sd_priv(host);
+	struct dma_chan *chan;
+
+	chan = dma_request_chan(mmc_dev(host->mmc), "rx-tx");
+	if (IS_ERR(chan)) {
+		dev_warn(mmc_dev(host->mmc),
+			 "failed to request DMA channel. falling back to PIO\n");
+		return;	/* just use PIO even for -EPROBE_DEFER */
+	}
+
+	/* this driver uses a single channel for both RX an TX */
+	priv->chan = chan;
+	host->chan_rx = chan;
+	host->chan_tx = chan;
+
+	tasklet_init(&host->dma_issue, uniphier_sd_external_dma_issue,
+		     (unsigned long)host);
+}
+
+static void uniphier_sd_external_dma_release(struct tmio_mmc_host *host)
+{
+	struct uniphier_sd_priv *priv = uniphier_sd_priv(host);
+
+	if (priv->chan)
+		dma_release_channel(priv->chan);
+}
+
+static void uniphier_sd_external_dma_abort(struct tmio_mmc_host *host)
+{
+	struct uniphier_sd_priv *priv = uniphier_sd_priv(host);
+
+	uniphier_sd_dma_endisable(host, 0);
+
+	if (priv->chan)
+		dmaengine_terminate_sync(priv->chan);
+}
+
+static void uniphier_sd_external_dma_dataend(struct tmio_mmc_host *host)
+{
+	uniphier_sd_dma_endisable(host, 0);
+
+	tmio_mmc_do_data_irq(host);
+}
+
+static const struct tmio_mmc_dma_ops uniphier_sd_external_dma_ops = {
+	.start = uniphier_sd_external_dma_start,
+	.enable = uniphier_sd_external_dma_enable,
+	.request = uniphier_sd_external_dma_request,
+	.release = uniphier_sd_external_dma_release,
+	.abort = uniphier_sd_external_dma_abort,
+	.dataend = uniphier_sd_external_dma_dataend,
+};
+
+static void uniphier_sd_internal_dma_issue(unsigned long arg)
+{
+	struct tmio_mmc_host *host = (void *)arg;
+	unsigned long flags;
+
+	spin_lock_irqsave(&host->lock, flags);
+	tmio_mmc_enable_mmc_irqs(host, TMIO_STAT_DATAEND);
+	spin_unlock_irqrestore(&host->lock, flags);
+
+	uniphier_sd_dma_endisable(host, 1);
+	writel(UNIPHIER_SD_DMA_CTL_START, host->ctl + UNIPHIER_SD_DMA_CTL);
+}
+
+static void uniphier_sd_internal_dma_start(struct tmio_mmc_host *host,
+					   struct mmc_data *data)
+{
+	struct uniphier_sd_priv *priv = uniphier_sd_priv(host);
+	struct scatterlist *sg = host->sg_ptr;
+	dma_addr_t dma_addr;
+	unsigned int dma_mode_dir;
+	u32 dma_mode;
+	int sg_len;
+
+	if (WARN_ON(host->sg_len != 1))
+		goto force_pio;
+
+	if (!IS_ALIGNED(sg->offset, 8))
+		goto force_pio;
+
+	if (data->flags & MMC_DATA_READ) {
+		priv->dma_dir = DMA_FROM_DEVICE;
+		dma_mode_dir = UNIPHIER_SD_DMA_MODE_DIR_FROM_DEV;
+	} else {
+		priv->dma_dir = DMA_TO_DEVICE;
+		dma_mode_dir = UNIPHIER_SD_DMA_MODE_DIR_TO_DEV;
+	}
+
+	sg_len = dma_map_sg(mmc_dev(host->mmc), sg, 1, priv->dma_dir);
+	if (sg_len == 0)
+		goto force_pio;
+
+	dma_mode = FIELD_PREP(UNIPHIER_SD_DMA_MODE_DIR_MASK, dma_mode_dir);
+	dma_mode |= FIELD_PREP(UNIPHIER_SD_DMA_MODE_WIDTH_MASK,
+			       UNIPHIER_SD_DMA_MODE_WIDTH_64);
+	dma_mode |= UNIPHIER_SD_DMA_MODE_ADDR_INC;
+
+	writel(dma_mode, host->ctl + UNIPHIER_SD_DMA_MODE);
+
+	dma_addr = sg_dma_address(data->sg);
+	writel(lower_32_bits(dma_addr), host->ctl + UNIPHIER_SD_DMA_ADDR_L);
+	writel(upper_32_bits(dma_addr), host->ctl + UNIPHIER_SD_DMA_ADDR_H);
+
+	return;
+force_pio:
+	host->force_pio = true;
+	uniphier_sd_dma_endisable(host, 0);
+}
+
+static void uniphier_sd_internal_dma_enable(struct tmio_mmc_host *host,
+					    bool enable)
+{
+}
+
+static void uniphier_sd_internal_dma_request(struct tmio_mmc_host *host,
+					     struct tmio_mmc_data *pdata)
+{
+	struct uniphier_sd_priv *priv = uniphier_sd_priv(host);
+
+	/*
+	 * Due to a hardware bug, Pro5 cannot use DMA for RX.
+	 * We can still use DMA for TX, but PIO for RX.
+	 */
+	if (!(priv->caps & UNIPHIER_SD_CAP_BROKEN_DMA_RX))
+		host->chan_rx = (void *)0xdeadbeaf;
+
+	host->chan_tx = (void *)0xdeadbeaf;
+
+	tasklet_init(&host->dma_issue, uniphier_sd_internal_dma_issue,
+		     (unsigned long)host);
+}
+
+static void uniphier_sd_internal_dma_release(struct tmio_mmc_host *host)
+{
+	/* Each value is set to zero to assume "disabling" each DMA */
+	host->chan_rx = NULL;
+	host->chan_tx = NULL;
+}
+
+static void uniphier_sd_internal_dma_abort(struct tmio_mmc_host *host)
+{
+	u32 tmp;
+
+	uniphier_sd_dma_endisable(host, 0);
+
+	tmp = readl(host->ctl + UNIPHIER_SD_DMA_RST);
+	tmp &= ~(UNIPHIER_SD_DMA_RST_CH1 | UNIPHIER_SD_DMA_RST_CH0);
+	writel(tmp, host->ctl + UNIPHIER_SD_DMA_RST);
+
+	tmp |= UNIPHIER_SD_DMA_RST_CH1 | UNIPHIER_SD_DMA_RST_CH0;
+	writel(tmp, host->ctl + UNIPHIER_SD_DMA_RST);
+}
+
+static void uniphier_sd_internal_dma_dataend(struct tmio_mmc_host *host)
+{
+	struct uniphier_sd_priv *priv = uniphier_sd_priv(host);
+
+	uniphier_sd_dma_endisable(host, 0);
+	dma_unmap_sg(mmc_dev(host->mmc), host->sg_ptr, 1, priv->dma_dir);
+
+	tmio_mmc_do_data_irq(host);
+}
+
+static const struct tmio_mmc_dma_ops uniphier_sd_internal_dma_ops = {
+	.start = uniphier_sd_internal_dma_start,
+	.enable = uniphier_sd_internal_dma_enable,
+	.request = uniphier_sd_internal_dma_request,
+	.release = uniphier_sd_internal_dma_release,
+	.abort = uniphier_sd_internal_dma_abort,
+	.dataend = uniphier_sd_internal_dma_dataend,
+};
+
+static int uniphier_sd_clk_enable(struct tmio_mmc_host *host)
+{
+	struct uniphier_sd_priv *priv = uniphier_sd_priv(host);
+	struct mmc_host *mmc = host->mmc;
+	int ret;
+
+	ret = clk_prepare_enable(priv->clk);
+	if (ret)
+		return ret;
+
+	ret = clk_set_rate(priv->clk, ULONG_MAX);
+	if (ret)
+		goto disable_clk;
+
+	priv->clk_rate = clk_get_rate(priv->clk);
+
+	/* If max-frequency property is set, use it. */
+	if (!mmc->f_max)
+		mmc->f_max = priv->clk_rate;
+
+	/*
+	 * 1/512 is the finest divisor in the original IP.  Newer versions
+	 * also supports 1/1024 divisor. (UniPhier-specific extension)
+	 */
+	if (priv->caps & UNIPHIER_SD_CAP_EXTENDED_IP)
+		mmc->f_min = priv->clk_rate / 1024;
+	else
+		mmc->f_min = priv->clk_rate / 512;
+
+	ret = reset_control_deassert(priv->rst);
+	if (ret)
+		goto disable_clk;
+
+	ret = reset_control_deassert(priv->rst_br);
+	if (ret)
+		goto assert_rst;
+
+	return 0;
+
+assert_rst:
+	reset_control_assert(priv->rst);
+disable_clk:
+	clk_disable_unprepare(priv->clk);
+
+	return ret;
+}
+
+static void uniphier_sd_clk_disable(struct tmio_mmc_host *host)
+{
+	struct uniphier_sd_priv *priv = uniphier_sd_priv(host);
+
+	reset_control_assert(priv->rst_br);
+	reset_control_assert(priv->rst);
+	clk_disable_unprepare(priv->clk);
+}
+
+static void uniphier_sd_hw_reset(struct tmio_mmc_host *host)
+{
+	struct uniphier_sd_priv *priv = uniphier_sd_priv(host);
+
+	reset_control_assert(priv->rst_hw);
+	/* For eMMC, minimum is 1us but give it 9us for good measure */
+	udelay(9);
+	reset_control_deassert(priv->rst_hw);
+	/* For eMMC, minimum is 200us but give it 300us for good measure */
+	usleep_range(300, 1000);
+}
+
+static void uniphier_sd_set_clock(struct tmio_mmc_host *host,
+				  unsigned int clock)
+{
+	struct uniphier_sd_priv *priv = uniphier_sd_priv(host);
+	unsigned long divisor;
+	u32 tmp;
+
+	tmp = readl(host->ctl + (CTL_SD_CARD_CLK_CTL << 1));
+
+	/* stop the clock before changing its rate to avoid a glitch signal */
+	tmp &= ~CLK_CTL_SCLKEN;
+	writel(tmp, host->ctl + (CTL_SD_CARD_CLK_CTL << 1));
+
+	if (clock == 0)
+		return;
+
+	tmp &= ~UNIPHIER_SD_CLK_CTL_DIV1024;
+	tmp &= ~UNIPHIER_SD_CLK_CTL_DIV1;
+	tmp &= ~CLK_CTL_DIV_MASK;
+
+	divisor = priv->clk_rate / clock;
+
+	/*
+	 * In the original IP, bit[7:0] represents the divisor.
+	 * bit7 set: 1/512, ... bit0 set:1/4, all bits clear: 1/2
+	 *
+	 * The IP does not define a way to achieve 1/1.  For UniPhier variants,
+	 * bit10 is used for 1/1.  Newer versions of UniPhier variants use
+	 * bit16 for 1/1024.
+	 */
+	if (divisor <= 1)
+		tmp |= UNIPHIER_SD_CLK_CTL_DIV1;
+	else if (priv->caps & UNIPHIER_SD_CAP_EXTENDED_IP && divisor > 512)
+		tmp |= UNIPHIER_SD_CLK_CTL_DIV1024;
+	else
+		tmp |= roundup_pow_of_two(divisor) >> 2;
+
+	writel(tmp, host->ctl + (CTL_SD_CARD_CLK_CTL << 1));
+
+	tmp |= CLK_CTL_SCLKEN;
+	writel(tmp, host->ctl + (CTL_SD_CARD_CLK_CTL << 1));
+}
+
+static void uniphier_sd_host_init(struct tmio_mmc_host *host)
+{
+	struct uniphier_sd_priv *priv = uniphier_sd_priv(host);
+	u32 val;
+
+	/*
+	 * Connected to 32bit AXI.
+	 * This register holds settings for SoC-specific internal bus
+	 * connection.  What is worse, the register spec was changed,
+	 * breaking the backward compatibility.  Write an appropriate
+	 * value depending on a flag associated with a compatible string.
+	 */
+	if (priv->caps & UNIPHIER_SD_CAP_EXTENDED_IP)
+		val = 0x00000101;
+	else
+		val = 0x00000000;
+
+	writel(val, host->ctl + UNIPHIER_SD_HOST_MODE);
+
+	val = 0;
+	/*
+	 * If supported, the controller can automatically
+	 * enable/disable the clock line to the card.
+	 */
+	if (priv->caps & UNIPHIER_SD_CAP_EXTENDED_IP)
+		val |= UNIPHIER_SD_CLKCTL_OFFEN;
+
+	writel(val, host->ctl + (CTL_SD_CARD_CLK_CTL << 1));
+}
+
+static int uniphier_sd_start_signal_voltage_switch(struct mmc_host *mmc,
+						   struct mmc_ios *ios)
+{
+	struct tmio_mmc_host *host = mmc_priv(mmc);
+	struct uniphier_sd_priv *priv = uniphier_sd_priv(host);
+	struct pinctrl_state *pinstate;
+	u32 val, tmp;
+
+	switch (ios->signal_voltage) {
+	case MMC_SIGNAL_VOLTAGE_330:
+		val = UNIPHIER_SD_VOLT_330;
+		pinstate = priv->pinstate_default;
+		break;
+	case MMC_SIGNAL_VOLTAGE_180:
+		val = UNIPHIER_SD_VOLT_180;
+		pinstate = priv->pinstate_uhs;
+		break;
+	default:
+		return -ENOTSUPP;
+	}
+
+	tmp = readl(host->ctl + UNIPHIER_SD_VOLT);
+	tmp &= ~UNIPHIER_SD_VOLT_MASK;
+	tmp |= FIELD_PREP(UNIPHIER_SD_VOLT_MASK, val);
+	writel(tmp, host->ctl + UNIPHIER_SD_VOLT);
+
+	pinctrl_select_state(priv->pinctrl, pinstate);
+
+	return 0;
+}
+
+static int uniphier_sd_uhs_init(struct tmio_mmc_host *host,
+				struct uniphier_sd_priv *priv)
+{
+	priv->pinctrl = devm_pinctrl_get(mmc_dev(host->mmc));
+	if (IS_ERR(priv->pinctrl))
+		return PTR_ERR(priv->pinctrl);
+
+	priv->pinstate_default = pinctrl_lookup_state(priv->pinctrl,
+						      PINCTRL_STATE_DEFAULT);
+	if (IS_ERR(priv->pinstate_default))
+		return PTR_ERR(priv->pinstate_default);
+
+	priv->pinstate_uhs = pinctrl_lookup_state(priv->pinctrl, "uhs");
+	if (IS_ERR(priv->pinstate_uhs))
+		return PTR_ERR(priv->pinstate_uhs);
+
+	host->ops.start_signal_voltage_switch =
+					uniphier_sd_start_signal_voltage_switch;
+
+	return 0;
+}
+
+static int uniphier_sd_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct uniphier_sd_priv *priv;
+	struct tmio_mmc_data *tmio_data;
+	struct tmio_mmc_host *host;
+	int irq, ret;
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0) {
+		dev_err(dev, "failed to get IRQ number");
+		return irq;
+	}
+
+	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	priv->caps = (unsigned long)of_device_get_match_data(dev);
+
+	priv->clk = devm_clk_get(dev, NULL);
+	if (IS_ERR(priv->clk)) {
+		dev_err(dev, "failed to get clock\n");
+		return PTR_ERR(priv->clk);
+	}
+
+	priv->rst = devm_reset_control_get_shared(dev, "host");
+	if (IS_ERR(priv->rst)) {
+		dev_err(dev, "failed to get host reset\n");
+		return PTR_ERR(priv->rst);
+	}
+
+	/* old version has one more reset */
+	if (!(priv->caps & UNIPHIER_SD_CAP_EXTENDED_IP)) {
+		priv->rst_br = devm_reset_control_get_shared(dev, "bridge");
+		if (IS_ERR(priv->rst_br)) {
+			dev_err(dev, "failed to get bridge reset\n");
+			return PTR_ERR(priv->rst_br);
+		}
+	}
+
+	tmio_data = &priv->tmio_data;
+	tmio_data->flags |= TMIO_MMC_32BIT_DATA_PORT;
+
+	host = tmio_mmc_host_alloc(pdev, tmio_data);
+	if (IS_ERR(host))
+		return PTR_ERR(host);
+
+	if (host->mmc->caps & MMC_CAP_HW_RESET) {
+		priv->rst_hw = devm_reset_control_get_exclusive(dev, "hw");
+		if (IS_ERR(priv->rst_hw)) {
+			dev_err(dev, "failed to get hw reset\n");
+			ret = PTR_ERR(priv->rst_hw);
+			goto free_host;
+		}
+		host->hw_reset = uniphier_sd_hw_reset;
+	}
+
+	if (host->mmc->caps & MMC_CAP_UHS) {
+		ret = uniphier_sd_uhs_init(host, priv);
+		if (ret) {
+			dev_warn(dev,
+				 "failed to setup UHS (error %d).  Disabling UHS.",
+				 ret);
+			host->mmc->caps &= ~MMC_CAP_UHS;
+		}
+	}
+
+	ret = devm_request_irq(dev, irq, tmio_mmc_irq, IRQF_SHARED,
+			       dev_name(dev), host);
+	if (ret)
+		goto free_host;
+
+	if (priv->caps & UNIPHIER_SD_CAP_EXTENDED_IP)
+		host->dma_ops = &uniphier_sd_internal_dma_ops;
+	else
+		host->dma_ops = &uniphier_sd_external_dma_ops;
+
+	host->bus_shift = 1;
+	host->clk_enable = uniphier_sd_clk_enable;
+	host->clk_disable = uniphier_sd_clk_disable;
+	host->set_clock = uniphier_sd_set_clock;
+
+	ret = uniphier_sd_clk_enable(host);
+	if (ret)
+		goto free_host;
+
+	uniphier_sd_host_init(host);
+
+	tmio_data->ocr_mask = MMC_VDD_32_33 | MMC_VDD_33_34;
+	if (host->mmc->caps & MMC_CAP_UHS)
+		tmio_data->ocr_mask |= MMC_VDD_165_195;
+
+	tmio_data->max_segs = 1;
+	tmio_data->max_blk_count = U16_MAX;
+
+	ret = tmio_mmc_host_probe(host);
+	if (ret)
+		goto free_host;
+
+	return 0;
+
+free_host:
+	tmio_mmc_host_free(host);
+
+	return ret;
+}
+
+static int uniphier_sd_remove(struct platform_device *pdev)
+{
+	struct tmio_mmc_host *host = platform_get_drvdata(pdev);
+
+	tmio_mmc_host_remove(host);
+	uniphier_sd_clk_disable(host);
+
+	return 0;
+}
+
+static const struct of_device_id uniphier_sd_match[] = {
+	{
+		.compatible = "socionext,uniphier-sd-v2.91",
+	},
+	{
+		.compatible = "socionext,uniphier-sd-v3.1",
+		.data = (void *)(UNIPHIER_SD_CAP_EXTENDED_IP |
+				 UNIPHIER_SD_CAP_BROKEN_DMA_RX),
+	},
+	{
+		.compatible = "socionext,uniphier-sd-v3.1.1",
+		.data = (void *)UNIPHIER_SD_CAP_EXTENDED_IP,
+	},
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, uniphier_sd_match);
+
+static struct platform_driver uniphier_sd_driver = {
+	.probe = uniphier_sd_probe,
+	.remove = uniphier_sd_remove,
+	.driver = {
+		.name = "uniphier-sd",
+		.of_match_table = uniphier_sd_match,
+	},
+};
+module_platform_driver(uniphier_sd_driver);
+
+MODULE_AUTHOR("Masahiro Yamada <yamada.masahiro@socionext.com>");
+MODULE_DESCRIPTION("UniPhier SD/eMMC host controller driver");
+MODULE_LICENSE("GPL v2");