diff mbox series

[V4,02/25] mmc: mmci: create generic mmci_dma_setup

Message ID 1538482167-13819-3-git-send-email-ludovic.Barre@st.com (mailing list archive)
State New, archived
Headers show
Series mmc: mmci: add sdmmc variant for stm32 | expand

Commit Message

Ludovic BARRE Oct. 2, 2018, 12:09 p.m. UTC 
From: Ludovic Barre <ludovic.barre@st.com>

This patch creates a generic mmci_dma_setup which calls
dma_setup callback of mmci_host_ops and manages common features
like use_dma... If there is a fallbacks to pio mode, dma
functions must check use_dma.

If one of dma channels is not defined (in dma engine config)
release channels.

Signed-off-by: Ludovic Barre <ludovic.barre@st.com>
---
change v4:
Adds mmci_dma_release prototype into CONFIG_DMA_ENGINE config,
allows to be call by mmci_dmae_setup for error management.
This prototype will be removed when dma release callback
will be add (defined in .h and removed of "else CONFIG_DMA_ENGINE")

 drivers/mmc/host/mmci.c          | 58 +++++++++++++++++++++++++++++++++-------
 drivers/mmc/host/mmci.h          |  7 ++++-
 drivers/mmc/host/mmci_qcom_dml.c |  9 +++++--
 3 files changed, 61 insertions(+), 13 deletions(-)

Comments

Ulf Hansson Oct. 3, 2018, 9:22 a.m. UTC | #1 
+ Srinivas

[...]

>  #ifdef CONFIG_DMA_ENGINE
> -static void mmci_dma_setup(struct mmci_host *host)
> +static inline void mmci_dma_release(struct mmci_host *host);
> +
> +int mmci_dmae_setup(struct mmci_host *host)
>  {
>         const char *rxname, *txname;
>
> @@ -464,8 +485,12 @@ static void mmci_dma_setup(struct mmci_host *host)
>                         host->mmc->max_seg_size = max_seg_size;
>         }
>
> -       if (host->ops && host->ops->dma_setup)
> -               host->ops->dma_setup(host);
> +       if (!host->dma_tx_channel || !host->dma_rx_channel) {
> +               mmci_dma_release(host);

This doesn't look right to me. The existing code allows a tx channel
to be used, even if an rx channel could not be setup. It seems
reasonable to still allow that.

> +               return -EINVAL;
> +       }
> +
> +       return 0;
>  }
>
>  /*
> @@ -496,7 +521,7 @@ static void mmci_dma_unmap(struct mmci_host *host, struct mmc_data *data)
>
>  static void mmci_dma_data_error(struct mmci_host *host)
>  {
> -       if (!dma_inprogress(host))
> +       if (!host->use_dma || !dma_inprogress(host))

Adding the check for use_dma here seems like an unnecessary check,
unless there is a reason for it due to following changes on top. In
such case, please make it a part of the patch(es) where it's actually
needed.

>                 return;
>
>         dev_err(mmc_dev(host->mmc), "error during DMA transfer!\n");
> @@ -514,7 +539,7 @@ static void mmci_dma_finalize(struct mmci_host *host, struct mmc_data *data)
>         u32 status;
>         int i;
>
> -       if (!dma_inprogress(host))
> +       if (!host->use_dma || !dma_inprogress(host))

Ditto.

>                 return;
>
>         /* Wait up to 1ms for the DMA to complete */
> @@ -546,6 +571,7 @@ static void mmci_dma_finalize(struct mmci_host *host, struct mmc_data *data)
>         if (status & MCI_RXDATAAVLBLMASK) {
>                 dev_err(mmc_dev(host->mmc), "buggy DMA detected. Taking evasive action.\n");
>                 mmci_dma_release(host);
> +               host->use_dma = false;
>         }
>
>         host->dma_in_progress = false;
> @@ -640,6 +666,9 @@ static int mmci_dma_start_data(struct mmci_host *host, unsigned int datactrl)
>         int ret;
>         struct mmc_data *data = host->data;
>
> +       if (!host->use_dma)
> +               return -EINVAL;
> +
>         ret = mmci_dma_prep_data(host, host->data);
>         if (ret)
>                 return ret;
> @@ -674,6 +703,9 @@ static void mmci_get_next_data(struct mmci_host *host, struct mmc_data *data)
>  {
>         struct mmci_host_next *next = &host->next_data;
>
> +       if (!host->use_dma)
> +               return;
> +
>         WARN_ON(data->host_cookie && data->host_cookie != next->cookie);
>         WARN_ON(!data->host_cookie && (next->dma_desc || next->dma_chan));
>
> @@ -689,7 +721,7 @@ static void mmci_pre_request(struct mmc_host *mmc, struct mmc_request *mrq)
>         struct mmc_data *data = mrq->data;
>         struct mmci_host_next *nd = &host->next_data;
>
> -       if (!data)
> +       if (!host->use_dma || !data)
>                 return;
>
>         BUG_ON(data->host_cookie);
> @@ -707,7 +739,7 @@ static void mmci_post_request(struct mmc_host *mmc, struct mmc_request *mrq,
>         struct mmci_host *host = mmc_priv(mmc);
>         struct mmc_data *data = mrq->data;
>
> -       if (!data || !data->host_cookie)
> +       if (!host->use_dma || !data || !data->host_cookie)

Ditto.

>                 return;
>
>         mmci_dma_unmap(host, data);
> @@ -735,14 +767,14 @@ static void mmci_post_request(struct mmc_host *mmc, struct mmc_request *mrq,
>         }
>  }
>
> +static struct mmci_host_ops mmci_variant_ops = {
> +       .dma_setup = mmci_dmae_setup,
> +};
>  #else
>  /* Blank functions if the DMA engine is not available */
>  static void mmci_get_next_data(struct mmci_host *host, struct mmc_data *data)
>  {
>  }
> -static inline void mmci_dma_setup(struct mmci_host *host)
> -{
> -}
>
>  static inline void mmci_dma_release(struct mmci_host *host)
>  {
> @@ -765,8 +797,14 @@ static inline int mmci_dma_start_data(struct mmci_host *host, unsigned int datac
>  #define mmci_pre_request NULL
>  #define mmci_post_request NULL
>
> +static struct mmci_host_ops mmci_variant_ops = {};

This seems a bit unnecessary. See more about why, below.

>  #endif
>
> +void mmci_variant_init(struct mmci_host *host)

Looks like you should make mmci_variant_init() internal to mmci.c,
thus covert it to static.

Moreover, I suggest you define a "static inline void
mmci_variant_init()", when CONFIG_DMA_ENGINE is unset. In that way you
don't need to assign host->ops at all for this case.

> +{
> +       host->ops = &mmci_variant_ops;
> +}
> +
>  static void mmci_start_data(struct mmci_host *host, struct mmc_data *data)
>  {
>         struct variant_data *variant = host->variant;
> diff --git a/drivers/mmc/host/mmci.h b/drivers/mmc/host/mmci.h
> index 01e6c6b..f7fe80f 100644
> --- a/drivers/mmc/host/mmci.h
> +++ b/drivers/mmc/host/mmci.h
> @@ -273,7 +273,7 @@ struct variant_data {
>
>  /* mmci variant callbacks */
>  struct mmci_host_ops {
> -       void (*dma_setup)(struct mmci_host *host);
> +       int (*dma_setup)(struct mmci_host *host);
>  };
>
>  struct mmci_host_next {
> @@ -323,6 +323,7 @@ struct mmci_host {
>         unsigned int            size;
>         int (*get_rx_fifocnt)(struct mmci_host *h, u32 status, int remain);
>
> +       u8                      use_dma:1;
>  #ifdef CONFIG_DMA_ENGINE
>         /* DMA stuff */
>         struct dma_chan         *dma_current;
> @@ -336,3 +337,7 @@ struct mmci_host {
>  #endif
>  };
>
> +void mmci_variant_init(struct mmci_host *host);
> +
> +int mmci_dmae_setup(struct mmci_host *host);
> +
> diff --git a/drivers/mmc/host/mmci_qcom_dml.c b/drivers/mmc/host/mmci_qcom_dml.c
> index be3fab5..c8d7592 100644
> --- a/drivers/mmc/host/mmci_qcom_dml.c
> +++ b/drivers/mmc/host/mmci_qcom_dml.c
> @@ -119,19 +119,22 @@ static int of_get_dml_pipe_index(struct device_node *np, const char *name)
>  }
>
>  /* Initialize the dml hardware connected to SD Card controller */
> -static void qcom_dma_setup(struct mmci_host *host)
> +static int qcom_dma_setup(struct mmci_host *host)
>  {
>         u32 config;
>         void __iomem *base;
>         int consumer_id, producer_id;
>         struct device_node *np = host->mmc->parent->of_node;
>
> +       if (mmci_dmae_setup(host))
> +               return -EINVAL;
> +
>         consumer_id = of_get_dml_pipe_index(np, "tx");
>         producer_id = of_get_dml_pipe_index(np, "rx");
>
>         if (producer_id < 0 || consumer_id < 0) {
>                 host->variant->qcom_dml = false;
> -               return;
> +               return -EINVAL;

Seems like you need to call a corresponding dma release function here,
before returning the error code.

Probably an "mmci_dmae_release()" needs to be implemented as a part of
this change - and then also called from here. This is according to
Srinivas recommendations, which means falling back to pio. As a matter
of fact this also needs to be clearly stated in the changelog, as you
are really also improving the behavior for the Qcom variant.

Unfortunate, I am not able to test this as I don't have the HW (which
I thought I had). Perhaps Srinivas can help, once we have something
ready for him to test.

>         }
>
>         base = host->base + DML_OFFSET;
> @@ -175,6 +178,8 @@ static void qcom_dma_setup(struct mmci_host *host)
>
>         /* Make sure dml initialization is finished */
>         mb();
> +
> +       return 0;
>  }
>
>  static struct mmci_host_ops qcom_variant_ops = {
> --
> 2.7.4
>

Kind regards
Uffe
Ludovic BARRE Oct. 3, 2018, 11:44 a.m. UTC | #2 
hi Ulf

On 10/03/2018 11:22 AM, Ulf Hansson wrote:
> + Srinivas

for next series, I will add Srinivas

> 
> [...]
> 
>>   #ifdef CONFIG_DMA_ENGINE
>> -static void mmci_dma_setup(struct mmci_host *host)
>> +static inline void mmci_dma_release(struct mmci_host *host);
>> +
>> +int mmci_dmae_setup(struct mmci_host *host)
>>   {
>>          const char *rxname, *txname;
>>
>> @@ -464,8 +485,12 @@ static void mmci_dma_setup(struct mmci_host *host)
>>                          host->mmc->max_seg_size = max_seg_size;
>>          }
>>
>> -       if (host->ops && host->ops->dma_setup)
>> -               host->ops->dma_setup(host);
>> +       if (!host->dma_tx_channel || !host->dma_rx_channel) {
>> +               mmci_dma_release(host);
> 
> This doesn't look right to me. The existing code allows a tx channel
> to be used, even if an rx channel could not be setup. It seems
> reasonable to still allow that.

ok, I could replace by
if (!host->dma_tx_channel && !host->dma_rx_channel)

> 
>> +               return -EINVAL;
>> +       }
>> +
>> +       return 0;
>>   }
>>
>>   /*
>> @@ -496,7 +521,7 @@ static void mmci_dma_unmap(struct mmci_host *host, struct mmc_data *data)
>>
>>   static void mmci_dma_data_error(struct mmci_host *host)
>>   {
>> -       if (!dma_inprogress(host))
>> +       if (!host->use_dma || !dma_inprogress(host))
> 
> Adding the check for use_dma here seems like an unnecessary check,
> unless there is a reason for it due to following changes on top. In
> such case, please make it a part of the patch(es) where it's actually
> needed.

In Fact, these checks are add to ensure the pio fallback, if only this 
patch it's taken. In the next commit of serie, these checks are moved to 
common functions mmci_dma_XX function.

> 
>>                  return;
>>
>>          dev_err(mmc_dev(host->mmc), "error during DMA transfer!\n");
>> @@ -514,7 +539,7 @@ static void mmci_dma_finalize(struct mmci_host *host, struct mmc_data *data)
>>          u32 status;
>>          int i;
>>
>> -       if (!dma_inprogress(host))
>> +       if (!host->use_dma || !dma_inprogress(host))
> 
> Ditto.
> 
>>                  return;
>>
>>          /* Wait up to 1ms for the DMA to complete */
>> @@ -546,6 +571,7 @@ static void mmci_dma_finalize(struct mmci_host *host, struct mmc_data *data)
>>          if (status & MCI_RXDATAAVLBLMASK) {
>>                  dev_err(mmc_dev(host->mmc), "buggy DMA detected. Taking evasive action.\n");
>>                  mmci_dma_release(host);
>> +               host->use_dma = false;
>>          }
>>
>>          host->dma_in_progress = false;
>> @@ -640,6 +666,9 @@ static int mmci_dma_start_data(struct mmci_host *host, unsigned int datactrl)
>>          int ret;
>>          struct mmc_data *data = host->data;
>>
>> +       if (!host->use_dma)
>> +               return -EINVAL;
>> +
>>          ret = mmci_dma_prep_data(host, host->data);
>>          if (ret)
>>                  return ret;
>> @@ -674,6 +703,9 @@ static void mmci_get_next_data(struct mmci_host *host, struct mmc_data *data)
>>   {
>>          struct mmci_host_next *next = &host->next_data;
>>
>> +       if (!host->use_dma)
>> +               return;
>> +
>>          WARN_ON(data->host_cookie && data->host_cookie != next->cookie);
>>          WARN_ON(!data->host_cookie && (next->dma_desc || next->dma_chan));
>>
>> @@ -689,7 +721,7 @@ static void mmci_pre_request(struct mmc_host *mmc, struct mmc_request *mrq)
>>          struct mmc_data *data = mrq->data;
>>          struct mmci_host_next *nd = &host->next_data;
>>
>> -       if (!data)
>> +       if (!host->use_dma || !data)
>>                  return;
>>
>>          BUG_ON(data->host_cookie);
>> @@ -707,7 +739,7 @@ static void mmci_post_request(struct mmc_host *mmc, struct mmc_request *mrq,
>>          struct mmci_host *host = mmc_priv(mmc);
>>          struct mmc_data *data = mrq->data;
>>
>> -       if (!data || !data->host_cookie)
>> +       if (!host->use_dma || !data || !data->host_cookie)
> 
> Ditto.
> 
>>                  return;
>>
>>          mmci_dma_unmap(host, data);
>> @@ -735,14 +767,14 @@ static void mmci_post_request(struct mmc_host *mmc, struct mmc_request *mrq,
>>          }
>>   }
>>
>> +static struct mmci_host_ops mmci_variant_ops = {
>> +       .dma_setup = mmci_dmae_setup,
>> +};
>>   #else
>>   /* Blank functions if the DMA engine is not available */
>>   static void mmci_get_next_data(struct mmci_host *host, struct mmc_data *data)
>>   {
>>   }
>> -static inline void mmci_dma_setup(struct mmci_host *host)
>> -{
>> -}
>>
>>   static inline void mmci_dma_release(struct mmci_host *host)
>>   {
>> @@ -765,8 +797,14 @@ static inline int mmci_dma_start_data(struct mmci_host *host, unsigned int datac
>>   #define mmci_pre_request NULL
>>   #define mmci_post_request NULL
>>
>> +static struct mmci_host_ops mmci_variant_ops = {};
> 
> This seems a bit unnecessary. See more about why, below.
> 
>>   #endif
>>
>> +void mmci_variant_init(struct mmci_host *host)
> 
> Looks like you should make mmci_variant_init() internal to mmci.c,
> thus covert it to static.
> 
> Moreover, I suggest you define a "static inline void
> mmci_variant_init()", when CONFIG_DMA_ENGINE is unset. In that way you
> don't need to assign host->ops at all for this case.

OK, no problem

> 
>> +{
>> +       host->ops = &mmci_variant_ops;
>> +}
>> +
>>   static void mmci_start_data(struct mmci_host *host, struct mmc_data *data)
>>   {
>>          struct variant_data *variant = host->variant;
>> diff --git a/drivers/mmc/host/mmci.h b/drivers/mmc/host/mmci.h
>> index 01e6c6b..f7fe80f 100644
>> --- a/drivers/mmc/host/mmci.h
>> +++ b/drivers/mmc/host/mmci.h
>> @@ -273,7 +273,7 @@ struct variant_data {
>>
>>   /* mmci variant callbacks */
>>   struct mmci_host_ops {
>> -       void (*dma_setup)(struct mmci_host *host);
>> +       int (*dma_setup)(struct mmci_host *host);
>>   };
>>
>>   struct mmci_host_next {
>> @@ -323,6 +323,7 @@ struct mmci_host {
>>          unsigned int            size;
>>          int (*get_rx_fifocnt)(struct mmci_host *h, u32 status, int remain);
>>
>> +       u8                      use_dma:1;
>>   #ifdef CONFIG_DMA_ENGINE
>>          /* DMA stuff */
>>          struct dma_chan         *dma_current;
>> @@ -336,3 +337,7 @@ struct mmci_host {
>>   #endif
>>   };
>>
>> +void mmci_variant_init(struct mmci_host *host);
>> +
>> +int mmci_dmae_setup(struct mmci_host *host);
>> +
>> diff --git a/drivers/mmc/host/mmci_qcom_dml.c b/drivers/mmc/host/mmci_qcom_dml.c
>> index be3fab5..c8d7592 100644
>> --- a/drivers/mmc/host/mmci_qcom_dml.c
>> +++ b/drivers/mmc/host/mmci_qcom_dml.c
>> @@ -119,19 +119,22 @@ static int of_get_dml_pipe_index(struct device_node *np, const char *name)
>>   }
>>
>>   /* Initialize the dml hardware connected to SD Card controller */
>> -static void qcom_dma_setup(struct mmci_host *host)
>> +static int qcom_dma_setup(struct mmci_host *host)
>>   {
>>          u32 config;
>>          void __iomem *base;
>>          int consumer_id, producer_id;
>>          struct device_node *np = host->mmc->parent->of_node;
>>
>> +       if (mmci_dmae_setup(host))
>> +               return -EINVAL;
>> +
>>          consumer_id = of_get_dml_pipe_index(np, "tx");
>>          producer_id = of_get_dml_pipe_index(np, "rx");
>>
>>          if (producer_id < 0 || consumer_id < 0) {
>>                  host->variant->qcom_dml = false;
>> -               return;
>> +               return -EINVAL;
> 
> Seems like you need to call a corresponding dma release function here,
> before returning the error code.
> 
> Probably an "mmci_dmae_release()" needs to be implemented as a part of
> this change - and then also called from here. This is according to
> Srinivas recommendations, which means falling back to pio. As a matter
> of fact this also needs to be clearly stated in the changelog, as you
> are really also improving the behavior for the Qcom variant.

it's in relation with the comment on
+       if (!host->dma_tx_channel || !host->dma_rx_channel) {

So yes.
At first sight Qcom need to have a tx and rx channel,
I will add mmci_dmae_release before returning error code.

> 
> Unfortunate, I am not able to test this as I don't have the HW (which
> I thought I had). Perhaps Srinivas can help, once we have something
> ready for him to test.
> 
>>          }
>>
>>          base = host->base + DML_OFFSET;
>> @@ -175,6 +178,8 @@ static void qcom_dma_setup(struct mmci_host *host)
>>
>>          /* Make sure dml initialization is finished */
>>          mb();
>> +
>> +       return 0;
>>   }
>>
>>   static struct mmci_host_ops qcom_variant_ops = {
>> --
>> 2.7.4
>>
> 
> Kind regards
> Uffe
>
diff mbox series

Patch

diff --git a/drivers/mmc/host/mmci.c b/drivers/mmc/host/mmci.c
index db8c085..2dc37f5 100644
--- a/drivers/mmc/host/mmci.c
+++ b/drivers/mmc/host/mmci.c
@@ -57,6 +57,7 @@  static struct variant_data variant_arm = {
 	.mmcimask1		= true,
 	.start_err		= MCI_STARTBITERR,
 	.opendrain		= MCI_ROD,
+	.init			= mmci_variant_init,
 };
 
 static struct variant_data variant_arm_extended_fifo = {
@@ -68,6 +69,7 @@  static struct variant_data variant_arm_extended_fifo = {
 	.mmcimask1		= true,
 	.start_err		= MCI_STARTBITERR,
 	.opendrain		= MCI_ROD,
+	.init			= mmci_variant_init,
 };
 
 static struct variant_data variant_arm_extended_fifo_hwfc = {
@@ -80,6 +82,7 @@  static struct variant_data variant_arm_extended_fifo_hwfc = {
 	.mmcimask1		= true,
 	.start_err		= MCI_STARTBITERR,
 	.opendrain		= MCI_ROD,
+	.init			= mmci_variant_init,
 };
 
 static struct variant_data variant_u300 = {
@@ -98,6 +101,7 @@  static struct variant_data variant_u300 = {
 	.mmcimask1		= true,
 	.start_err		= MCI_STARTBITERR,
 	.opendrain		= MCI_OD,
+	.init			= mmci_variant_init,
 };
 
 static struct variant_data variant_nomadik = {
@@ -117,6 +121,7 @@  static struct variant_data variant_nomadik = {
 	.mmcimask1		= true,
 	.start_err		= MCI_STARTBITERR,
 	.opendrain		= MCI_OD,
+	.init			= mmci_variant_init,
 };
 
 static struct variant_data variant_ux500 = {
@@ -142,6 +147,7 @@  static struct variant_data variant_ux500 = {
 	.mmcimask1		= true,
 	.start_err		= MCI_STARTBITERR,
 	.opendrain		= MCI_OD,
+	.init			= mmci_variant_init,
 };
 
 static struct variant_data variant_ux500v2 = {
@@ -169,6 +175,7 @@  static struct variant_data variant_ux500v2 = {
 	.mmcimask1		= true,
 	.start_err		= MCI_STARTBITERR,
 	.opendrain		= MCI_OD,
+	.init			= mmci_variant_init,
 };
 
 static struct variant_data variant_stm32 = {
@@ -186,6 +193,7 @@  static struct variant_data variant_stm32 = {
 	.f_max			= 48000000,
 	.pwrreg_clkgate		= true,
 	.pwrreg_nopower		= true,
+	.init			= mmci_variant_init,
 };
 
 static struct variant_data variant_qcom = {
@@ -356,6 +364,17 @@  static void mmci_set_clkreg(struct mmci_host *host, unsigned int desired)
 	mmci_write_clkreg(host, clk);
 }
 
+void mmci_dma_setup(struct mmci_host *host)
+{
+	if (!host->ops || !host->ops->dma_setup)
+		return;
+
+	if (host->ops->dma_setup(host))
+		return;
+
+	host->use_dma = true;
+}
+
 static void
 mmci_request_end(struct mmci_host *host, struct mmc_request *mrq)
 {
@@ -414,7 +433,9 @@  static void mmci_init_sg(struct mmci_host *host, struct mmc_data *data)
  * no custom DMA interfaces are supported.
  */
 #ifdef CONFIG_DMA_ENGINE
-static void mmci_dma_setup(struct mmci_host *host)
+static inline void mmci_dma_release(struct mmci_host *host);
+
+int mmci_dmae_setup(struct mmci_host *host)
 {
 	const char *rxname, *txname;
 
@@ -464,8 +485,12 @@  static void mmci_dma_setup(struct mmci_host *host)
 			host->mmc->max_seg_size = max_seg_size;
 	}
 
-	if (host->ops && host->ops->dma_setup)
-		host->ops->dma_setup(host);
+	if (!host->dma_tx_channel || !host->dma_rx_channel) {
+		mmci_dma_release(host);
+		return -EINVAL;
+	}
+
+	return 0;
 }
 
 /*
@@ -496,7 +521,7 @@  static void mmci_dma_unmap(struct mmci_host *host, struct mmc_data *data)
 
 static void mmci_dma_data_error(struct mmci_host *host)
 {
-	if (!dma_inprogress(host))
+	if (!host->use_dma || !dma_inprogress(host))
 		return;
 
 	dev_err(mmc_dev(host->mmc), "error during DMA transfer!\n");
@@ -514,7 +539,7 @@  static void mmci_dma_finalize(struct mmci_host *host, struct mmc_data *data)
 	u32 status;
 	int i;
 
-	if (!dma_inprogress(host))
+	if (!host->use_dma || !dma_inprogress(host))
 		return;
 
 	/* Wait up to 1ms for the DMA to complete */
@@ -546,6 +571,7 @@  static void mmci_dma_finalize(struct mmci_host *host, struct mmc_data *data)
 	if (status & MCI_RXDATAAVLBLMASK) {
 		dev_err(mmc_dev(host->mmc), "buggy DMA detected. Taking evasive action.\n");
 		mmci_dma_release(host);
+		host->use_dma = false;
 	}
 
 	host->dma_in_progress = false;
@@ -640,6 +666,9 @@  static int mmci_dma_start_data(struct mmci_host *host, unsigned int datactrl)
 	int ret;
 	struct mmc_data *data = host->data;
 
+	if (!host->use_dma)
+		return -EINVAL;
+
 	ret = mmci_dma_prep_data(host, host->data);
 	if (ret)
 		return ret;
@@ -674,6 +703,9 @@  static void mmci_get_next_data(struct mmci_host *host, struct mmc_data *data)
 {
 	struct mmci_host_next *next = &host->next_data;
 
+	if (!host->use_dma)
+		return;
+
 	WARN_ON(data->host_cookie && data->host_cookie != next->cookie);
 	WARN_ON(!data->host_cookie && (next->dma_desc || next->dma_chan));
 
@@ -689,7 +721,7 @@  static void mmci_pre_request(struct mmc_host *mmc, struct mmc_request *mrq)
 	struct mmc_data *data = mrq->data;
 	struct mmci_host_next *nd = &host->next_data;
 
-	if (!data)
+	if (!host->use_dma || !data)
 		return;
 
 	BUG_ON(data->host_cookie);
@@ -707,7 +739,7 @@  static void mmci_post_request(struct mmc_host *mmc, struct mmc_request *mrq,
 	struct mmci_host *host = mmc_priv(mmc);
 	struct mmc_data *data = mrq->data;
 
-	if (!data || !data->host_cookie)
+	if (!host->use_dma || !data || !data->host_cookie)
 		return;
 
 	mmci_dma_unmap(host, data);
@@ -735,14 +767,14 @@  static void mmci_post_request(struct mmc_host *mmc, struct mmc_request *mrq,
 	}
 }
 
+static struct mmci_host_ops mmci_variant_ops = {
+	.dma_setup = mmci_dmae_setup,
+};
 #else
 /* Blank functions if the DMA engine is not available */
 static void mmci_get_next_data(struct mmci_host *host, struct mmc_data *data)
 {
 }
-static inline void mmci_dma_setup(struct mmci_host *host)
-{
-}
 
 static inline void mmci_dma_release(struct mmci_host *host)
 {
@@ -765,8 +797,14 @@  static inline int mmci_dma_start_data(struct mmci_host *host, unsigned int datac
 #define mmci_pre_request NULL
 #define mmci_post_request NULL
 
+static struct mmci_host_ops mmci_variant_ops = {};
 #endif
 
+void mmci_variant_init(struct mmci_host *host)
+{
+	host->ops = &mmci_variant_ops;
+}
+
 static void mmci_start_data(struct mmci_host *host, struct mmc_data *data)
 {
 	struct variant_data *variant = host->variant;
diff --git a/drivers/mmc/host/mmci.h b/drivers/mmc/host/mmci.h
index 01e6c6b..f7fe80f 100644
--- a/drivers/mmc/host/mmci.h
+++ b/drivers/mmc/host/mmci.h
@@ -273,7 +273,7 @@  struct variant_data {
 
 /* mmci variant callbacks */
 struct mmci_host_ops {
-	void (*dma_setup)(struct mmci_host *host);
+	int (*dma_setup)(struct mmci_host *host);
 };
 
 struct mmci_host_next {
@@ -323,6 +323,7 @@  struct mmci_host {
 	unsigned int		size;
 	int (*get_rx_fifocnt)(struct mmci_host *h, u32 status, int remain);
 
+	u8			use_dma:1;
 #ifdef CONFIG_DMA_ENGINE
 	/* DMA stuff */
 	struct dma_chan		*dma_current;
@@ -336,3 +337,7 @@  struct mmci_host {
 #endif
 };
 
+void mmci_variant_init(struct mmci_host *host);
+
+int mmci_dmae_setup(struct mmci_host *host);
+
diff --git a/drivers/mmc/host/mmci_qcom_dml.c b/drivers/mmc/host/mmci_qcom_dml.c
index be3fab5..c8d7592 100644
--- a/drivers/mmc/host/mmci_qcom_dml.c
+++ b/drivers/mmc/host/mmci_qcom_dml.c
@@ -119,19 +119,22 @@  static int of_get_dml_pipe_index(struct device_node *np, const char *name)
 }
 
 /* Initialize the dml hardware connected to SD Card controller */
-static void qcom_dma_setup(struct mmci_host *host)
+static int qcom_dma_setup(struct mmci_host *host)
 {
 	u32 config;
 	void __iomem *base;
 	int consumer_id, producer_id;
 	struct device_node *np = host->mmc->parent->of_node;
 
+	if (mmci_dmae_setup(host))
+		return -EINVAL;
+
 	consumer_id = of_get_dml_pipe_index(np, "tx");
 	producer_id = of_get_dml_pipe_index(np, "rx");
 
 	if (producer_id < 0 || consumer_id < 0) {
 		host->variant->qcom_dml = false;
-		return;
+		return -EINVAL;
 	}
 
 	base = host->base + DML_OFFSET;
@@ -175,6 +178,8 @@  static void qcom_dma_setup(struct mmci_host *host)
 
 	/* Make sure dml initialization is finished */
 	mb();
+
+	return 0;
 }
 
 static struct mmci_host_ops qcom_variant_ops = {