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* [RFC PATCH V2] scsi: ufs: Add specific callback for setting DMA mask
       [not found] <CGME20180308111416epcas1p4f9f1dbb36e8567121c6236ac0e9b4e03@epcas1p4.samsung.com>
@ 2018-03-08 11:03 ` Alim Akhtar
  2018-05-16  4:31   ` Alim Akhtar
  0 siblings, 1 reply; 4+ messages in thread
From: Alim Akhtar @ 2018-03-08 11:03 UTC (permalink / raw)
  To: linux-scsi, linux-kernel
  Cc: jejb, martin.petersen, vinholikatti, subhashj, devicetree, shaik.ameer

Currently DMA mask for UFS HCI is set by reading CAP register's
[64AS] bit. Some HCI controller like Exynos support 36-bit bus address.
This works perfectly fine with DMA mask set as 64 in case there is no
IOMMU attached to HCI.
In case if HCI is behind an IOMMU, setting DMA mask as 64 bit won't
work as HCI has only 36bit addressing and SMMU has created mapping of
64 bit and as the device truncates the address, its mapping will not
be found by iommu.
To resolve such issues, let the variant driver sets its own DMA mask.

Signed-off-by: Alim Akhtar <alim.akhtar@samsung.com>
---
 drivers/scsi/ufs/ufshcd.c | 3 +++
 drivers/scsi/ufs/ufshcd.h | 2 ++
 2 files changed, 5 insertions(+)

I am not sure if there are other ways available to handle such cases.
The IOMMU I am talking about is arm-smmu and it DT binding does not
give much idea about handling such cases.
Have tested this patch with HCI controller with IOMMU attached.

Changes Since V1: 
	- Fixed build issue as reported by Kbuild test robot.

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index a355d98..9a1374e 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -7781,6 +7781,9 @@ EXPORT_SYMBOL_GPL(ufshcd_dealloc_host);
  */
 static int ufshcd_set_dma_mask(struct ufs_hba *hba)
 {
+	if (hba->vops && hba->vops->set_dma_mask)
+		return hba->vops->set_dma_mask(hba);
+
 	if (hba->capabilities & MASK_64_ADDRESSING_SUPPORT) {
 		if (!dma_set_mask_and_coherent(hba->dev, DMA_BIT_MASK(64)))
 			return 0;
diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h
index 1332e54..89c6dae 100644
--- a/drivers/scsi/ufs/ufshcd.h
+++ b/drivers/scsi/ufs/ufshcd.h
@@ -297,6 +297,7 @@ struct ufs_pwr_mode_info {
  * @resume: called during host controller PM callback
  * @dbg_register_dump: used to dump controller debug information
  * @phy_initialization: used to initialize phys
+ * @set_dma_mask: used to set variant specific DMA mask
  */
 struct ufs_hba_variant_ops {
 	const char *name;
@@ -325,6 +326,7 @@ struct ufs_hba_variant_ops {
 	int     (*resume)(struct ufs_hba *, enum ufs_pm_op);
 	void	(*dbg_register_dump)(struct ufs_hba *hba);
 	int	(*phy_initialization)(struct ufs_hba *);
+	int	(*set_dma_mask)(struct ufs_hba *hba);
 };
 
 /* clock gating state  */
-- 
2.7.4

^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [RFC PATCH V2] scsi: ufs: Add specific callback for setting DMA mask
  2018-03-08 11:03 ` [RFC PATCH V2] scsi: ufs: Add specific callback for setting DMA mask Alim Akhtar
@ 2018-05-16  4:31   ` Alim Akhtar
  2018-05-16 21:31     ` Subhash Jadavani
  0 siblings, 1 reply; 4+ messages in thread
From: Alim Akhtar @ 2018-05-16  4:31 UTC (permalink / raw)
  To: Alim Akhtar
  Cc: linux-scsi, linux-kernel, jejb, martin.petersen,
	vinayak holikatti, subhashj, devicetree, Shaik Ameer Basha

Ping !!!

On Thu, Mar 8, 2018 at 4:33 PM, Alim Akhtar <alim.akhtar@samsung.com> wrote:
> Currently DMA mask for UFS HCI is set by reading CAP register's
> [64AS] bit. Some HCI controller like Exynos support 36-bit bus address.
> This works perfectly fine with DMA mask set as 64 in case there is no
> IOMMU attached to HCI.
> In case if HCI is behind an IOMMU, setting DMA mask as 64 bit won't
> work as HCI has only 36bit addressing and SMMU has created mapping of
> 64 bit and as the device truncates the address, its mapping will not
> be found by iommu.
> To resolve such issues, let the variant driver sets its own DMA mask.
>
> Signed-off-by: Alim Akhtar <alim.akhtar@samsung.com>
> ---
>  drivers/scsi/ufs/ufshcd.c | 3 +++
>  drivers/scsi/ufs/ufshcd.h | 2 ++
>  2 files changed, 5 insertions(+)
>
> I am not sure if there are other ways available to handle such cases.
> The IOMMU I am talking about is arm-smmu and it DT binding does not
> give much idea about handling such cases.
> Have tested this patch with HCI controller with IOMMU attached.
>
> Changes Since V1:
>         - Fixed build issue as reported by Kbuild test robot.
>
> diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
> index a355d98..9a1374e 100644
> --- a/drivers/scsi/ufs/ufshcd.c
> +++ b/drivers/scsi/ufs/ufshcd.c
> @@ -7781,6 +7781,9 @@ EXPORT_SYMBOL_GPL(ufshcd_dealloc_host);
>   */
>  static int ufshcd_set_dma_mask(struct ufs_hba *hba)
>  {
> +       if (hba->vops && hba->vops->set_dma_mask)
> +               return hba->vops->set_dma_mask(hba);
> +
>         if (hba->capabilities & MASK_64_ADDRESSING_SUPPORT) {
>                 if (!dma_set_mask_and_coherent(hba->dev, DMA_BIT_MASK(64)))
>                         return 0;
> diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h
> index 1332e54..89c6dae 100644
> --- a/drivers/scsi/ufs/ufshcd.h
> +++ b/drivers/scsi/ufs/ufshcd.h
> @@ -297,6 +297,7 @@ struct ufs_pwr_mode_info {
>   * @resume: called during host controller PM callback
>   * @dbg_register_dump: used to dump controller debug information
>   * @phy_initialization: used to initialize phys
> + * @set_dma_mask: used to set variant specific DMA mask
>   */
>  struct ufs_hba_variant_ops {
>         const char *name;
> @@ -325,6 +326,7 @@ struct ufs_hba_variant_ops {
>         int     (*resume)(struct ufs_hba *, enum ufs_pm_op);
>         void    (*dbg_register_dump)(struct ufs_hba *hba);
>         int     (*phy_initialization)(struct ufs_hba *);
> +       int     (*set_dma_mask)(struct ufs_hba *hba);
>  };
>
>  /* clock gating state  */
> --
> 2.7.4
>



-- 
Regards,
Alim

^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [RFC PATCH V2] scsi: ufs: Add specific callback for setting DMA mask
  2018-05-16  4:31   ` Alim Akhtar
@ 2018-05-16 21:31     ` Subhash Jadavani
  2018-05-20  1:35       ` Alim Akhtar
  0 siblings, 1 reply; 4+ messages in thread
From: Subhash Jadavani @ 2018-05-16 21:31 UTC (permalink / raw)
  To: Alim Akhtar
  Cc: Alim Akhtar, linux-scsi, linux-kernel, jejb, martin.petersen,
	vinayak holikatti, devicetree, Shaik Ameer Basha

On 2018-05-15 21:31, Alim Akhtar wrote:
> Ping !!!
> 
> On Thu, Mar 8, 2018 at 4:33 PM, Alim Akhtar <alim.akhtar@samsung.com> 
> wrote:
>> Currently DMA mask for UFS HCI is set by reading CAP register's
>> [64AS] bit. Some HCI controller like Exynos support 36-bit bus 
>> address.
>> This works perfectly fine with DMA mask set as 64 in case there is no
>> IOMMU attached to HCI.
>> In case if HCI is behind an IOMMU, setting DMA mask as 64 bit won't
>> work as HCI has only 36bit addressing and SMMU has created mapping of
>> 64 bit and as the device truncates the address, its mapping will not
>> be found by iommu.
>> To resolve such issues, let the variant driver sets its own DMA mask.
>> 
>> Signed-off-by: Alim Akhtar <alim.akhtar@samsung.com>
>> ---
>>  drivers/scsi/ufs/ufshcd.c | 3 +++
>>  drivers/scsi/ufs/ufshcd.h | 2 ++
>>  2 files changed, 5 insertions(+)
>> 
>> I am not sure if there are other ways available to handle such cases.
>> The IOMMU I am talking about is arm-smmu and it DT binding does not
>> give much idea about handling such cases.
>> Have tested this patch with HCI controller with IOMMU attached.
>> 
>> Changes Since V1:
>>         - Fixed build issue as reported by Kbuild test robot.
>> 
>> diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
>> index a355d98..9a1374e 100644
>> --- a/drivers/scsi/ufs/ufshcd.c
>> +++ b/drivers/scsi/ufs/ufshcd.c
>> @@ -7781,6 +7781,9 @@ EXPORT_SYMBOL_GPL(ufshcd_dealloc_host);
>>   */
>>  static int ufshcd_set_dma_mask(struct ufs_hba *hba)
>>  {
>> +       if (hba->vops && hba->vops->set_dma_mask)
>> +               return hba->vops->set_dma_mask(hba);
>> +
>>         if (hba->capabilities & MASK_64_ADDRESSING_SUPPORT) {
>>                 if (!dma_set_mask_and_coherent(hba->dev, 
>> DMA_BIT_MASK(64)))
>>                         return 0;
>> diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h
>> index 1332e54..89c6dae 100644
>> --- a/drivers/scsi/ufs/ufshcd.h
>> +++ b/drivers/scsi/ufs/ufshcd.h
>> @@ -297,6 +297,7 @@ struct ufs_pwr_mode_info {
>>   * @resume: called during host controller PM callback
>>   * @dbg_register_dump: used to dump controller debug information
>>   * @phy_initialization: used to initialize phys
>> + * @set_dma_mask: used to set variant specific DMA mask
>>   */
>>  struct ufs_hba_variant_ops {
>>         const char *name;
>> @@ -325,6 +326,7 @@ struct ufs_hba_variant_ops {
>>         int     (*resume)(struct ufs_hba *, enum ufs_pm_op);
>>         void    (*dbg_register_dump)(struct ufs_hba *hba);
>>         int     (*phy_initialization)(struct ufs_hba *);
>> +       int     (*set_dma_mask)(struct ufs_hba *hba);
>>  };
>> 
>>  /* clock gating state  */
>> --
>> 2.7.4
>> 

Looks reasonable to me, you may try posting non-RFC version.

-- 
The Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project

^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [RFC PATCH V2] scsi: ufs: Add specific callback for setting DMA mask
  2018-05-16 21:31     ` Subhash Jadavani
@ 2018-05-20  1:35       ` Alim Akhtar
  0 siblings, 0 replies; 4+ messages in thread
From: Alim Akhtar @ 2018-05-20  1:35 UTC (permalink / raw)
  To: Subhash Jadavani, alim.akhtar
  Cc: linux-scsi, linux-kernel, jejb, martin.petersen,
	vinayak holikatti, devicetree, Shaik Ameer Basha

Hi Subhash

On 05/17/2018 03:01 AM, Subhash Jadavani wrote:
> On 2018-05-15 21:31, Alim Akhtar wrote:
>> Ping !!!
>>
>> On Thu, Mar 8, 2018 at 4:33 PM, Alim Akhtar <alim.akhtar@samsung.com> 
>> wrote:
>>> Currently DMA mask for UFS HCI is set by reading CAP register's
>>> [64AS] bit. Some HCI controller like Exynos support 36-bit bus address.
>>> This works perfectly fine with DMA mask set as 64 in case there is no
>>> IOMMU attached to HCI.
>>> In case if HCI is behind an IOMMU, setting DMA mask as 64 bit won't
>>> work as HCI has only 36bit addressing and SMMU has created mapping of
>>> 64 bit and as the device truncates the address, its mapping will not
>>> be found by iommu.
>>> To resolve such issues, let the variant driver sets its own DMA mask.
>>>
>>> Signed-off-by: Alim Akhtar <alim.akhtar@samsung.com>
>>> ---
>>>  drivers/scsi/ufs/ufshcd.c | 3 +++
>>>  drivers/scsi/ufs/ufshcd.h | 2 ++
>>>  2 files changed, 5 insertions(+)
>>>
>>> I am not sure if there are other ways available to handle such cases.
>>> The IOMMU I am talking about is arm-smmu and it DT binding does not
>>> give much idea about handling such cases.
>>> Have tested this patch with HCI controller with IOMMU attached.
>>>
>>> Changes Since V1:
>>>         - Fixed build issue as reported by Kbuild test robot.
>>>
>>> diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
>>> index a355d98..9a1374e 100644
>>> --- a/drivers/scsi/ufs/ufshcd.c
>>> +++ b/drivers/scsi/ufs/ufshcd.c
>>> @@ -7781,6 +7781,9 @@ EXPORT_SYMBOL_GPL(ufshcd_dealloc_host);
>>>   */
>>>  static int ufshcd_set_dma_mask(struct ufs_hba *hba)
>>>  {
>>> +       if (hba->vops && hba->vops->set_dma_mask)
>>> +               return hba->vops->set_dma_mask(hba);
>>> +
>>>         if (hba->capabilities & MASK_64_ADDRESSING_SUPPORT) {
>>>                 if (!dma_set_mask_and_coherent(hba->dev, 
>>> DMA_BIT_MASK(64)))
>>>                         return 0;
>>> diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h
>>> index 1332e54..89c6dae 100644
>>> --- a/drivers/scsi/ufs/ufshcd.h
>>> +++ b/drivers/scsi/ufs/ufshcd.h
>>> @@ -297,6 +297,7 @@ struct ufs_pwr_mode_info {
>>>   * @resume: called during host controller PM callback
>>>   * @dbg_register_dump: used to dump controller debug information
>>>   * @phy_initialization: used to initialize phys
>>> + * @set_dma_mask: used to set variant specific DMA mask
>>>   */
>>>  struct ufs_hba_variant_ops {
>>>         const char *name;
>>> @@ -325,6 +326,7 @@ struct ufs_hba_variant_ops {
>>>         int     (*resume)(struct ufs_hba *, enum ufs_pm_op);
>>>         void    (*dbg_register_dump)(struct ufs_hba *hba);
>>>         int     (*phy_initialization)(struct ufs_hba *);
>>> +       int     (*set_dma_mask)(struct ufs_hba *hba);
>>>  };
>>>
>>>  /* clock gating state  */
>>> -- 
>>> 2.7.4
>>>
> 
> Looks reasonable to me, you may try posting non-RFC version.
> 
Thanks for review.
Will send a non-RFC version.

Regards,
Alim

^ permalink raw reply	[flat|nested] 4+ messages in thread

end of thread, other threads:[~2018-05-20  1:48 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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     [not found] <CGME20180308111416epcas1p4f9f1dbb36e8567121c6236ac0e9b4e03@epcas1p4.samsung.com>
2018-03-08 11:03 ` [RFC PATCH V2] scsi: ufs: Add specific callback for setting DMA mask Alim Akhtar
2018-05-16  4:31   ` Alim Akhtar
2018-05-16 21:31     ` Subhash Jadavani
2018-05-20  1:35       ` Alim Akhtar

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