diff mbox series

[RFC,1/3] mmc: sdhci: add support for using external DMA devices

Message ID 1541387810-24867-2-git-send-email-zhang.chunyan@linaro.org (mailing list archive)
State New, archived
Headers show
Series Add support for using external dma in SDHCI | expand

Commit Message

Chunyan Zhang Nov. 5, 2018, 3:16 a.m. UTC 
Some standard SD host controller can support both external dma
controllers as well as ADMA in which the controller acts as
DMA master.

Currently the generic SDHCI code supports ADMA/SDMA integrated into
the host controller but does not have any support for external DMA
controllers implemented using dmaengine meaning that custom code is
needed for any systems that use a generic DMA controller with SDHCI.

Signed-off-by: Chunyan Zhang <zhang.chunyan@linaro.org>
---
 drivers/mmc/host/Kconfig |  13 +++++
 drivers/mmc/host/sdhci.c | 137 ++++++++++++++++++++++++++++++++++++++++++++++-
 drivers/mmc/host/sdhci.h |  12 +++++
 3 files changed, 161 insertions(+), 1 deletion(-)

Comments

Arnd Bergmann Nov. 6, 2018, 11:16 a.m. UTC | #1 
On 11/5/18, Chunyan Zhang <zhang.chunyan@linaro.org> wrote:
> Some standard SD host controller can support both external dma
> controllers as well as ADMA in which the controller acts as
> DMA master.
>
> Currently the generic SDHCI code supports ADMA/SDMA integrated into
> the host controller but does not have any support for external DMA
> controllers implemented using dmaengine meaning that custom code is
> needed for any systems that use a generic DMA controller with SDHCI.
>
> Signed-off-by: Chunyan Zhang <zhang.chunyan@linaro.org>

Looks good to me overall, but I think I found one small bug:


> +	dma->rx_chan = dma_request_chan(mmc->parent, "rx");
> +	if (IS_ERR(dma->rx_chan)) {
> +		ret = PTR_ERR(dma->rx_chan);
> +		if (ret == -EPROBE_DEFER && dma->tx_chan)
> +			dma_release_channel(dma->tx_chan);
> +
> +		dma->rx_chan = NULL;
> +		pr_warn("Failed to request RX DMA channel.\n");
> +	}

The error handling looks wrong here: if you get EPROBE_DEFER,
you want to skip the warning message. If you get any other error code,
you want the warning message and also the dma_release_channel()
which should be unconditional here.

        Arnd
Chunyan Zhang Nov. 7, 2018, 2:56 a.m. UTC | #2 
On Tue, 6 Nov 2018 at 19:16, Arnd Bergmann <arnd@arndb.de> wrote:
>
> On 11/5/18, Chunyan Zhang <zhang.chunyan@linaro.org> wrote:
> > Some standard SD host controller can support both external dma
> > controllers as well as ADMA in which the controller acts as
> > DMA master.
> >
> > Currently the generic SDHCI code supports ADMA/SDMA integrated into
> > the host controller but does not have any support for external DMA
> > controllers implemented using dmaengine meaning that custom code is
> > needed for any systems that use a generic DMA controller with SDHCI.
> >
> > Signed-off-by: Chunyan Zhang <zhang.chunyan@linaro.org>
>
> Looks good to me overall, but I think I found one small bug:
>
>
> > +     dma->rx_chan = dma_request_chan(mmc->parent, "rx");
> > +     if (IS_ERR(dma->rx_chan)) {
> > +             ret = PTR_ERR(dma->rx_chan);
> > +             if (ret == -EPROBE_DEFER && dma->tx_chan)
> > +                     dma_release_channel(dma->tx_chan);
> > +
> > +             dma->rx_chan = NULL;
> > +             pr_warn("Failed to request RX DMA channel.\n");
> > +     }
>
> The error handling looks wrong here: if you get EPROBE_DEFER,
> you want to skip the warning message. If you get any other error code,

Right, will address.

> you want the warning message and also the dma_release_channel()
> which should be unconditional here.

Will address.

Thanks for the review,
Chunyan

>
>         Arnd
Adrian Hunter Nov. 7, 2018, 2:13 p.m. UTC | #3 
On 5/11/18 5:16 AM, Chunyan Zhang wrote:
> Some standard SD host controller can support both external dma
> controllers as well as ADMA in which the controller acts as
> DMA master.
> 
> Currently the generic SDHCI code supports ADMA/SDMA integrated into
> the host controller but does not have any support for external DMA
> controllers implemented using dmaengine meaning that custom code is
> needed for any systems that use a generic DMA controller with SDHCI.

I have no object to supporting external DMA, but there are a few comments below.

> 
> Signed-off-by: Chunyan Zhang <zhang.chunyan@linaro.org>
> ---
>  drivers/mmc/host/Kconfig |  13 +++++
>  drivers/mmc/host/sdhci.c | 137 ++++++++++++++++++++++++++++++++++++++++++++++-
>  drivers/mmc/host/sdhci.h |  12 +++++
>  3 files changed, 161 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/mmc/host/Kconfig b/drivers/mmc/host/Kconfig
> index 1b58739..c4745d8 100644
> --- a/drivers/mmc/host/Kconfig
> +++ b/drivers/mmc/host/Kconfig
> @@ -977,3 +977,16 @@ config MMC_SDHCI_OMAP
>  	  If you have a controller with this interface, say Y or M here.
>  
>  	  If unsure, say N.
> +
> +config MMC_SDHCI_EXTDMA
> +        bool "Support external DMA in standard SD host controller"
> +	depends on MMC_SDHCI
> +	depends on DMA_ENGINE
> +	help
> +	  This is an option for using external DMA device via dmaengine
> +	  framework.
> +
> +	  If you have a controller which supports using external DMA device
> +	  for data transfer, can say Y.
> +
> +	  If unsure, say N.
> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
> index 99bdae5..ffb1d2b 100644
> --- a/drivers/mmc/host/sdhci.c
> +++ b/drivers/mmc/host/sdhci.c
> @@ -14,6 +14,7 @@
>   */
>  
>  #include <linux/delay.h>
> +#include <linux/dmaengine.h>
>  #include <linux/ktime.h>
>  #include <linux/highmem.h>
>  #include <linux/io.h>
> @@ -1309,6 +1310,128 @@ static void sdhci_del_timer(struct sdhci_host *host, struct mmc_request *mrq)
>  		del_timer(&host->timer);
>  }
>  
> +#if IS_ENABLED(CONFIG_MMC_SDHCI_EXTDMA)
> +static int sdhci_extdma_init_chan(struct sdhci_host *host)

I would prefer "external_dma" to extdma e.g.
	CONFIG_MMC_SDHCI_EXTERNAL_DMA
	sdhci_external_dma_init
	sdhci_external_dma_channel
	sdhci_external_dma_setup
	etc


> +{
> +	int ret = 0;
> +	struct mmc_host *mmc = host->mmc;
> +	struct sdhci_extdma *dma = &host->extdma;
> +
> +	dma->tx_chan = dma_request_chan(mmc->parent, "tx");
> +	if (IS_ERR(dma->tx_chan)) {
> +		ret = PTR_ERR(dma->tx_chan);
> +		dma->tx_chan = NULL;
> +		pr_warn("Failed to request TX DMA channel.\n");
> +		return ret;
> +	}
> +
> +	dma->rx_chan = dma_request_chan(mmc->parent, "rx");
> +	if (IS_ERR(dma->rx_chan)) {
> +		ret = PTR_ERR(dma->rx_chan);
> +		if (ret == -EPROBE_DEFER && dma->tx_chan)
> +			dma_release_channel(dma->tx_chan);
> +
> +		dma->rx_chan = NULL;
> +		pr_warn("Failed to request RX DMA channel.\n");
> +	}

I guess the channels need to be released in sdhci_cleanup_host() and
sdhci_remove_host()

> +
> +	return ret;
> +}
> +
> +static inline struct dma_chan *
> +sdhci_extdma_get_chan(struct sdhci_extdma *dma, struct mmc_data *data)
> +{
> +	return data->flags & MMC_DATA_WRITE ? dma->tx_chan : dma->rx_chan;
> +}
> +
> +static int sdhci_extdma_setup(struct sdhci_host *host, struct mmc_command *cmd)
> +{
> +	int ret = 0, i;
> +	struct dma_async_tx_descriptor *desc;
> +	struct mmc_data *data = cmd->data;
> +	struct dma_chan *chan;
> +	struct dma_slave_config cfg;
> +
> +	if (!host->mapbase)
> +		return -EINVAL;
> +
> +	cfg.src_addr = host->mapbase + SDHCI_BUFFER;
> +	cfg.dst_addr = host->mapbase + SDHCI_BUFFER;
> +	cfg.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
> +	cfg.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
> +	cfg.src_maxburst = data->blksz / 4;
> +	cfg.dst_maxburst = data->blksz / 4;
> +
> +	/* Sanity check: all the SG entries must be aligned by block size. */
> +	for (i = 0; i < data->sg_len; i++) {
> +		if ((data->sg + i)->length % data->blksz)
> +			return -EINVAL;
> +	}
> +
> +	chan = sdhci_extdma_get_chan(&host->extdma, data);
> +
> +	ret = dmaengine_slave_config(chan, &cfg);
> +	if (ret)
> +		return ret;
> +
> +	desc = dmaengine_prep_slave_sg(chan, data->sg, data->sg_len,
> +				       mmc_get_dma_dir(data),
> +				       DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
> +	if (!desc)
> +		return -EINVAL;
> +
> +	desc->callback = NULL;
> +	desc->callback_param = NULL;
> +
> +	dmaengine_submit(desc);

Doesn't the DMA need to be cleaned up somewhere if there are transfer errors?

> +
> +	return 0;
> +}
> +
> +static void sdhci_extdma_prepare_data(struct sdhci_host *host,
> +				      struct mmc_command *cmd)
> +{
> +	host->flags |= SDHCI_REQ_USE_DMA;
> +	sdhci_prepare_data(host, cmd);
> +
> +	if (sdhci_extdma_setup(host, cmd))
> +		dev_err(mmc_dev(host->mmc), "MMC start dma failure\n");
> +}
> +
> +static void sdhci_extdma_pre_transfer(struct sdhci_host *host,
> +				      struct mmc_command *cmd)
> +{
> +	struct dma_chan *chan = sdhci_extdma_get_chan(&host->extdma, cmd->data);
> +
> +	if (cmd->opcode != MMC_SET_BLOCK_COUNT) {
> +		sdhci_set_timeout(host, cmd);
> +		dma_async_issue_pending(chan);
> +	}
> +}
> +#else
> +static int sdhci_extdma_init_chan(struct sdhci_host *host)
> +{
> +	return 0;
> +}
> +
> +static void sdhci_extdma_prepare_data(struct sdhci_host *host,
> +				      struct mmc_command *cmd)
> +{
> +	/* If SDHCI_EXTDMA not supported, PIO will be used */
> +	sdhci_prepare_data(host, cmd);
> +}
> +
> +static void sdhci_extdma_pre_transfer(struct sdhci_host *host,
> +				      struct mmc_command *cmd)
> +{}
> +#endif
> +
> +void sdhci_switch_extdma(struct sdhci_host *host, bool en)
> +{
> +	host->use_extdma = en;
> +}
> +EXPORT_SYMBOL_GPL(sdhci_switch_extdma);
> +
>  void sdhci_send_command(struct sdhci_host *host, struct mmc_command *cmd)
>  {
>  	int flags;
> @@ -1355,7 +1478,10 @@ void sdhci_send_command(struct sdhci_host *host, struct mmc_command *cmd)
>  		host->data_cmd = cmd;
>  	}
>  
> -	sdhci_prepare_data(host, cmd);
> +	if (host->use_extdma)
> +		sdhci_extdma_prepare_data(host, cmd);
> +	else
> +		sdhci_prepare_data(host, cmd);
>  
>  	sdhci_writel(host, cmd->arg, SDHCI_ARGUMENT);
>  
> @@ -1397,6 +1523,9 @@ void sdhci_send_command(struct sdhci_host *host, struct mmc_command *cmd)
>  		timeout += 10 * HZ;
>  	sdhci_mod_timer(host, cmd->mrq, timeout);
>  
> +	if (host->use_extdma)
> +		sdhci_extdma_pre_transfer(host, cmd);
> +
>  	sdhci_writew(host, SDHCI_MAKE_CMD(cmd->opcode, flags), SDHCI_COMMAND);
>  }
>  EXPORT_SYMBOL_GPL(sdhci_send_command);
> @@ -4133,6 +4262,12 @@ int sdhci_setup_host(struct sdhci_host *host)
>  			return ret;
>  	}
>  
> +	if (host->use_extdma) {
> +		ret = sdhci_extdma_init_chan(host);
> +		if (ret)
> +			goto unreg;
> +	}
> +
>  	return 0;
>  
>  unreg:
> diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
> index b001cf4..2d4a3ba 100644
> --- a/drivers/mmc/host/sdhci.h
> +++ b/drivers/mmc/host/sdhci.h
> @@ -361,6 +361,12 @@ enum sdhci_cookie {
>  	COOKIE_MAPPED,		/* mapped by sdhci_prepare_data() */
>  };
>  
> +struct sdhci_extdma {
> +	struct sdhci_host	*host;
> +	struct dma_chan		*rx_chan;
> +	struct dma_chan		*tx_chan;
> +};

Is this struct really needed?  Otherwise kernel style is not to nest
structures. i.e. just put rx/tx_chan in struct sdhci_host.

> +
>  struct sdhci_host {
>  	/* Data set by hardware interface driver */
>  	const char *hw_name;	/* Hardware bus name */
> @@ -475,6 +481,7 @@ struct sdhci_host {
>  
>  	int irq;		/* Device IRQ */
>  	void __iomem *ioaddr;	/* Mapped address */
> +	phys_addr_t mapbase;	/* physical address base */
>  	char *bounce_buffer;	/* For packing SDMA reads/writes */
>  	dma_addr_t bounce_addr;
>  	unsigned int bounce_buffer_size;
> @@ -524,6 +531,7 @@ struct sdhci_host {
>  	bool pending_reset;	/* Cmd/data reset is pending */
>  	bool irq_wake_enabled;	/* IRQ wakeup is enabled */
>  	bool v4_mode;		/* Host Version 4 Enable */
> +	bool use_extdma;
>  
>  	struct mmc_request *mrqs_done[SDHCI_MAX_MRQS];	/* Requests done */
>  	struct mmc_command *cmd;	/* Current command */
> @@ -551,6 +559,9 @@ struct sdhci_host {
>  
>  	struct timer_list timer;	/* Timer for timeouts */
>  	struct timer_list data_timer;	/* Timer for data timeouts */
> +#if IS_ENABLED(CONFIG_MMC_SDHCI_EXTDMA)
> +	struct sdhci_extdma	extdma;	/* support external DMA */
> +#endif
>  
>  	u32 caps;		/* CAPABILITY_0 */
>  	u32 caps1;		/* CAPABILITY_1 */
> @@ -785,5 +796,6 @@ void sdhci_start_tuning(struct sdhci_host *host);
>  void sdhci_end_tuning(struct sdhci_host *host);
>  void sdhci_reset_tuning(struct sdhci_host *host);
>  void sdhci_send_tuning(struct sdhci_host *host, u32 opcode);
> +void sdhci_switch_extdma(struct sdhci_host *host, bool en);
>  
>  #endif /* __SDHCI_HW_H */
>
diff mbox series

Patch

diff --git a/drivers/mmc/host/Kconfig b/drivers/mmc/host/Kconfig
index 1b58739..c4745d8 100644
--- a/drivers/mmc/host/Kconfig
+++ b/drivers/mmc/host/Kconfig
@@ -977,3 +977,16 @@  config MMC_SDHCI_OMAP
 	  If you have a controller with this interface, say Y or M here.
 
 	  If unsure, say N.
+
+config MMC_SDHCI_EXTDMA
+        bool "Support external DMA in standard SD host controller"
+	depends on MMC_SDHCI
+	depends on DMA_ENGINE
+	help
+	  This is an option for using external DMA device via dmaengine
+	  framework.
+
+	  If you have a controller which supports using external DMA device
+	  for data transfer, can say Y.
+
+	  If unsure, say N.
diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index 99bdae5..ffb1d2b 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -14,6 +14,7 @@ 
  */
 
 #include <linux/delay.h>
+#include <linux/dmaengine.h>
 #include <linux/ktime.h>
 #include <linux/highmem.h>
 #include <linux/io.h>
@@ -1309,6 +1310,128 @@  static void sdhci_del_timer(struct sdhci_host *host, struct mmc_request *mrq)
 		del_timer(&host->timer);
 }
 
+#if IS_ENABLED(CONFIG_MMC_SDHCI_EXTDMA)
+static int sdhci_extdma_init_chan(struct sdhci_host *host)
+{
+	int ret = 0;
+	struct mmc_host *mmc = host->mmc;
+	struct sdhci_extdma *dma = &host->extdma;
+
+	dma->tx_chan = dma_request_chan(mmc->parent, "tx");
+	if (IS_ERR(dma->tx_chan)) {
+		ret = PTR_ERR(dma->tx_chan);
+		dma->tx_chan = NULL;
+		pr_warn("Failed to request TX DMA channel.\n");
+		return ret;
+	}
+
+	dma->rx_chan = dma_request_chan(mmc->parent, "rx");
+	if (IS_ERR(dma->rx_chan)) {
+		ret = PTR_ERR(dma->rx_chan);
+		if (ret == -EPROBE_DEFER && dma->tx_chan)
+			dma_release_channel(dma->tx_chan);
+
+		dma->rx_chan = NULL;
+		pr_warn("Failed to request RX DMA channel.\n");
+	}
+
+	return ret;
+}
+
+static inline struct dma_chan *
+sdhci_extdma_get_chan(struct sdhci_extdma *dma, struct mmc_data *data)
+{
+	return data->flags & MMC_DATA_WRITE ? dma->tx_chan : dma->rx_chan;
+}
+
+static int sdhci_extdma_setup(struct sdhci_host *host, struct mmc_command *cmd)
+{
+	int ret = 0, i;
+	struct dma_async_tx_descriptor *desc;
+	struct mmc_data *data = cmd->data;
+	struct dma_chan *chan;
+	struct dma_slave_config cfg;
+
+	if (!host->mapbase)
+		return -EINVAL;
+
+	cfg.src_addr = host->mapbase + SDHCI_BUFFER;
+	cfg.dst_addr = host->mapbase + SDHCI_BUFFER;
+	cfg.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
+	cfg.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
+	cfg.src_maxburst = data->blksz / 4;
+	cfg.dst_maxburst = data->blksz / 4;
+
+	/* Sanity check: all the SG entries must be aligned by block size. */
+	for (i = 0; i < data->sg_len; i++) {
+		if ((data->sg + i)->length % data->blksz)
+			return -EINVAL;
+	}
+
+	chan = sdhci_extdma_get_chan(&host->extdma, data);
+
+	ret = dmaengine_slave_config(chan, &cfg);
+	if (ret)
+		return ret;
+
+	desc = dmaengine_prep_slave_sg(chan, data->sg, data->sg_len,
+				       mmc_get_dma_dir(data),
+				       DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
+	if (!desc)
+		return -EINVAL;
+
+	desc->callback = NULL;
+	desc->callback_param = NULL;
+
+	dmaengine_submit(desc);
+
+	return 0;
+}
+
+static void sdhci_extdma_prepare_data(struct sdhci_host *host,
+				      struct mmc_command *cmd)
+{
+	host->flags |= SDHCI_REQ_USE_DMA;
+	sdhci_prepare_data(host, cmd);
+
+	if (sdhci_extdma_setup(host, cmd))
+		dev_err(mmc_dev(host->mmc), "MMC start dma failure\n");
+}
+
+static void sdhci_extdma_pre_transfer(struct sdhci_host *host,
+				      struct mmc_command *cmd)
+{
+	struct dma_chan *chan = sdhci_extdma_get_chan(&host->extdma, cmd->data);
+
+	if (cmd->opcode != MMC_SET_BLOCK_COUNT) {
+		sdhci_set_timeout(host, cmd);
+		dma_async_issue_pending(chan);
+	}
+}
+#else
+static int sdhci_extdma_init_chan(struct sdhci_host *host)
+{
+	return 0;
+}
+
+static void sdhci_extdma_prepare_data(struct sdhci_host *host,
+				      struct mmc_command *cmd)
+{
+	/* If SDHCI_EXTDMA not supported, PIO will be used */
+	sdhci_prepare_data(host, cmd);
+}
+
+static void sdhci_extdma_pre_transfer(struct sdhci_host *host,
+				      struct mmc_command *cmd)
+{}
+#endif
+
+void sdhci_switch_extdma(struct sdhci_host *host, bool en)
+{
+	host->use_extdma = en;
+}
+EXPORT_SYMBOL_GPL(sdhci_switch_extdma);
+
 void sdhci_send_command(struct sdhci_host *host, struct mmc_command *cmd)
 {
 	int flags;
@@ -1355,7 +1478,10 @@  void sdhci_send_command(struct sdhci_host *host, struct mmc_command *cmd)
 		host->data_cmd = cmd;
 	}
 
-	sdhci_prepare_data(host, cmd);
+	if (host->use_extdma)
+		sdhci_extdma_prepare_data(host, cmd);
+	else
+		sdhci_prepare_data(host, cmd);
 
 	sdhci_writel(host, cmd->arg, SDHCI_ARGUMENT);
 
@@ -1397,6 +1523,9 @@  void sdhci_send_command(struct sdhci_host *host, struct mmc_command *cmd)
 		timeout += 10 * HZ;
 	sdhci_mod_timer(host, cmd->mrq, timeout);
 
+	if (host->use_extdma)
+		sdhci_extdma_pre_transfer(host, cmd);
+
 	sdhci_writew(host, SDHCI_MAKE_CMD(cmd->opcode, flags), SDHCI_COMMAND);
 }
 EXPORT_SYMBOL_GPL(sdhci_send_command);
@@ -4133,6 +4262,12 @@  int sdhci_setup_host(struct sdhci_host *host)
 			return ret;
 	}
 
+	if (host->use_extdma) {
+		ret = sdhci_extdma_init_chan(host);
+		if (ret)
+			goto unreg;
+	}
+
 	return 0;
 
 unreg:
diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
index b001cf4..2d4a3ba 100644
--- a/drivers/mmc/host/sdhci.h
+++ b/drivers/mmc/host/sdhci.h
@@ -361,6 +361,12 @@  enum sdhci_cookie {
 	COOKIE_MAPPED,		/* mapped by sdhci_prepare_data() */
 };
 
+struct sdhci_extdma {
+	struct sdhci_host	*host;
+	struct dma_chan		*rx_chan;
+	struct dma_chan		*tx_chan;
+};
+
 struct sdhci_host {
 	/* Data set by hardware interface driver */
 	const char *hw_name;	/* Hardware bus name */
@@ -475,6 +481,7 @@  struct sdhci_host {
 
 	int irq;		/* Device IRQ */
 	void __iomem *ioaddr;	/* Mapped address */
+	phys_addr_t mapbase;	/* physical address base */
 	char *bounce_buffer;	/* For packing SDMA reads/writes */
 	dma_addr_t bounce_addr;
 	unsigned int bounce_buffer_size;
@@ -524,6 +531,7 @@  struct sdhci_host {
 	bool pending_reset;	/* Cmd/data reset is pending */
 	bool irq_wake_enabled;	/* IRQ wakeup is enabled */
 	bool v4_mode;		/* Host Version 4 Enable */
+	bool use_extdma;
 
 	struct mmc_request *mrqs_done[SDHCI_MAX_MRQS];	/* Requests done */
 	struct mmc_command *cmd;	/* Current command */
@@ -551,6 +559,9 @@  struct sdhci_host {
 
 	struct timer_list timer;	/* Timer for timeouts */
 	struct timer_list data_timer;	/* Timer for data timeouts */
+#if IS_ENABLED(CONFIG_MMC_SDHCI_EXTDMA)
+	struct sdhci_extdma	extdma;	/* support external DMA */
+#endif
 
 	u32 caps;		/* CAPABILITY_0 */
 	u32 caps1;		/* CAPABILITY_1 */
@@ -785,5 +796,6 @@  void sdhci_start_tuning(struct sdhci_host *host);
 void sdhci_end_tuning(struct sdhci_host *host);
 void sdhci_reset_tuning(struct sdhci_host *host);
 void sdhci_send_tuning(struct sdhci_host *host, u32 opcode);
+void sdhci_switch_extdma(struct sdhci_host *host, bool en);
 
 #endif /* __SDHCI_HW_H */