[U-Boot] [PATCH] mtd: nand: mxs: fix PIO_WORD number

[U-Boot] [PATCH] mtd: nand: mxs: fix PIO_WORD number

[Luca Ellero]

There is only one pio_word in this DMA transaction so data field must be 1.

Signed-off-by: Luca Ellero <luca.ellero@brickedbrain.com>
---
 drivers/mtd/nand/mxs_nand.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/mtd/nand/mxs_nand.c b/drivers/mtd/nand/mxs_nand.c
index 7a064ab..616c9ca 100644
--- a/drivers/mtd/nand/mxs_nand.c
+++ b/drivers/mtd/nand/mxs_nand.c
@@ -305,7 +305,7 @@ static void mxs_nand_cmd_ctrl(struct mtd_info *mtd, int data, unsigned int ctrl)
 	d->cmd.data =
 		MXS_DMA_DESC_COMMAND_DMA_READ | MXS_DMA_DESC_IRQ |
 		MXS_DMA_DESC_CHAIN | MXS_DMA_DESC_DEC_SEM |
-		MXS_DMA_DESC_WAIT4END | (3 << MXS_DMA_DESC_PIO_WORDS_OFFSET) |
+		MXS_DMA_DESC_WAIT4END | (1 << MXS_DMA_DESC_PIO_WORDS_OFFSET) |
 		(nand_info->cmd_queue_len << MXS_DMA_DESC_BYTES_OFFSET);
 
 	d->cmd.address = (dma_addr_t)nand_info->cmd_buf;
-- 
1.7.10.4

[U-Boot] [PATCH] mtd: nand: mxs: fix PIO_WORD number

[Stefan Roese]

Hi Luca,

On 10.12.2014 09:24, Luca Ellero wrote:
> There is only one pio_word in this DMA transaction so data field must be 1.
>
> Signed-off-by: Luca Ellero <luca.ellero@brickedbrain.com>
> ---
>   drivers/mtd/nand/mxs_nand.c |    2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/mtd/nand/mxs_nand.c b/drivers/mtd/nand/mxs_nand.c
> index 7a064ab..616c9ca 100644
> --- a/drivers/mtd/nand/mxs_nand.c
> +++ b/drivers/mtd/nand/mxs_nand.c
> @@ -305,7 +305,7 @@ static void mxs_nand_cmd_ctrl(struct mtd_info *mtd, int data, unsigned int ctrl)
>   	d->cmd.data =
>   		MXS_DMA_DESC_COMMAND_DMA_READ | MXS_DMA_DESC_IRQ |
>   		MXS_DMA_DESC_CHAIN | MXS_DMA_DESC_DEC_SEM |
> -		MXS_DMA_DESC_WAIT4END | (3 << MXS_DMA_DESC_PIO_WORDS_OFFSET) |
> +		MXS_DMA_DESC_WAIT4END | (1 << MXS_DMA_DESC_PIO_WORDS_OFFSET) |
>   		(nand_info->cmd_queue_len << MXS_DMA_DESC_BYTES_OFFSET);

What error or problem does this incorrect setup cause in your case? I'm 
asking since I'm also using this driver in some mx6 system and have not 
seen any issues.

Thanks,
Stefan

[U-Boot] [PATCH] mtd: nand: mxs: fix PIO_WORD number

[Luca Ellero]

Hi Stefan,

On 12/12/2014 09:43, Stefan Roese wrote:
> Hi Luca,
>
> On 10.12.2014 09:24, Luca Ellero wrote:
>> There is only one pio_word in this DMA transaction so data field must
>> be 1.
>>
>> Signed-off-by: Luca Ellero <luca.ellero@brickedbrain.com>
>> ---
>>   drivers/mtd/nand/mxs_nand.c |    2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/mtd/nand/mxs_nand.c b/drivers/mtd/nand/mxs_nand.c
>> index 7a064ab..616c9ca 100644
>> --- a/drivers/mtd/nand/mxs_nand.c
>> +++ b/drivers/mtd/nand/mxs_nand.c
>> @@ -305,7 +305,7 @@ static void mxs_nand_cmd_ctrl(struct mtd_info
>> *mtd, int data, unsigned int ctrl)
>>       d->cmd.data =
>>           MXS_DMA_DESC_COMMAND_DMA_READ | MXS_DMA_DESC_IRQ |
>>           MXS_DMA_DESC_CHAIN | MXS_DMA_DESC_DEC_SEM |
>> -        MXS_DMA_DESC_WAIT4END | (3 << MXS_DMA_DESC_PIO_WORDS_OFFSET) |
>> +        MXS_DMA_DESC_WAIT4END | (1 << MXS_DMA_DESC_PIO_WORDS_OFFSET) |
>>           (nand_info->cmd_queue_len << MXS_DMA_DESC_BYTES_OFFSET);
>
> What error or problem does this incorrect setup cause in your case? I'm
> asking since I'm also using this driver in some mx6 system and have not
> seen any issues.

As far as I can see, it doesn't seem to cause any issue. But, if you 
read the iMX6 Reference Manual (chapter 14.2) this field should reflect 
the number of PIO_WORDS appended to the DMA command, in this case 1.


-- 
Luca Ellero

E-mail: luca.ellero at brickedbrain.com
Internet: www.brickedbrain.com

[U-Boot] [PATCH] mtd: nand: mxs: fix PIO_WORD number

[Stefan Roese]

Hi Luca,

On 12.12.2014 13:40, Luca Ellero wrote:
>> On 10.12.2014 09:24, Luca Ellero wrote:
>>> There is only one pio_word in this DMA transaction so data field must
>>> be 1.
>>>
>>> Signed-off-by: Luca Ellero <luca.ellero@brickedbrain.com>
>>> ---
>>>   drivers/mtd/nand/mxs_nand.c |    2 +-
>>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/mtd/nand/mxs_nand.c b/drivers/mtd/nand/mxs_nand.c
>>> index 7a064ab..616c9ca 100644
>>> --- a/drivers/mtd/nand/mxs_nand.c
>>> +++ b/drivers/mtd/nand/mxs_nand.c
>>> @@ -305,7 +305,7 @@ static void mxs_nand_cmd_ctrl(struct mtd_info
>>> *mtd, int data, unsigned int ctrl)
>>>       d->cmd.data =
>>>           MXS_DMA_DESC_COMMAND_DMA_READ | MXS_DMA_DESC_IRQ |
>>>           MXS_DMA_DESC_CHAIN | MXS_DMA_DESC_DEC_SEM |
>>> -        MXS_DMA_DESC_WAIT4END | (3 << MXS_DMA_DESC_PIO_WORDS_OFFSET) |
>>> +        MXS_DMA_DESC_WAIT4END | (1 << MXS_DMA_DESC_PIO_WORDS_OFFSET) |
>>>           (nand_info->cmd_queue_len << MXS_DMA_DESC_BYTES_OFFSET);
>>
>> What error or problem does this incorrect setup cause in your case? I'm
>> asking since I'm also using this driver in some mx6 system and have not
>> seen any issues.
>
> As far as I can see, it doesn't seem to cause any issue. But, if you
> read the iMX6 Reference Manual (chapter 14.2) this field should reflect
> the number of PIO_WORDS appended to the DMA command, in this case 1.

Okay. I just wanted to check if this patch fixes a real problem that you 
have experienced. Thanks for the explanation.

Reviewed-by: Stefan Roese <sr@denx.de>

Thanks,
Stefan

[U-Boot] [PATCH] mtd: nand: mxs: fix PIO_WORD number

[Marek Vasut]

On Friday, December 12, 2014 at 01:43:22 PM, Stefan Roese wrote:
> Hi Luca,
> 
> On 12.12.2014 13:40, Luca Ellero wrote:
> >> On 10.12.2014 09:24, Luca Ellero wrote:
> >>> There is only one pio_word in this DMA transaction so data field must
> >>> be 1.
> >>> 
> >>> Signed-off-by: Luca Ellero <luca.ellero@brickedbrain.com>
> >>> ---
> >>> 
> >>>   drivers/mtd/nand/mxs_nand.c |    2 +-
> >>>   1 file changed, 1 insertion(+), 1 deletion(-)
> >>> 
> >>> diff --git a/drivers/mtd/nand/mxs_nand.c b/drivers/mtd/nand/mxs_nand.c
> >>> index 7a064ab..616c9ca 100644
> >>> --- a/drivers/mtd/nand/mxs_nand.c
> >>> +++ b/drivers/mtd/nand/mxs_nand.c
> >>> @@ -305,7 +305,7 @@ static void mxs_nand_cmd_ctrl(struct mtd_info
> >>> *mtd, int data, unsigned int ctrl)
> >>> 
> >>>       d->cmd.data =
> >>>       
> >>>           MXS_DMA_DESC_COMMAND_DMA_READ | MXS_DMA_DESC_IRQ |
> >>>           MXS_DMA_DESC_CHAIN | MXS_DMA_DESC_DEC_SEM |
> >>> 
> >>> -        MXS_DMA_DESC_WAIT4END | (3 << MXS_DMA_DESC_PIO_WORDS_OFFSET) |
> >>> +        MXS_DMA_DESC_WAIT4END | (1 << MXS_DMA_DESC_PIO_WORDS_OFFSET) |
> >>> 
> >>>           (nand_info->cmd_queue_len << MXS_DMA_DESC_BYTES_OFFSET);
> >> 
> >> What error or problem does this incorrect setup cause in your case? I'm
> >> asking since I'm also using this driver in some mx6 system and have not
> >> seen any issues.
> > 
> > As far as I can see, it doesn't seem to cause any issue. But, if you
> > read the iMX6 Reference Manual (chapter 14.2) this field should reflect
> > the number of PIO_WORDS appended to the DMA command, in this case 1.
> 
> Okay. I just wanted to check if this patch fixes a real problem that you
> have experienced. Thanks for the explanation.
> 
> Reviewed-by: Stefan Roese <sr@denx.de>

The patch does in fact change the behavior such that it no longer clears the 
ECCCTRL and COMPARE registers both on MX28 and on MX6 . Could this have some 
impact?

Best regards,
Marek Vasut

[U-Boot] [PATCH] mtd: nand: mxs: fix PIO_WORD number

[Luca Ellero]

Hi Marek,

On 12/12/2014 13:58, Marek Vasut wrote:
> On Friday, December 12, 2014 at 01:43:22 PM, Stefan Roese wrote:
>> Hi Luca,
>>
>> On 12.12.2014 13:40, Luca Ellero wrote:
>>>> On 10.12.2014 09:24, Luca Ellero wrote:
>>>>> There is only one pio_word in this DMA transaction so data field must
>>>>> be 1.
>>>>>
>>>>> Signed-off-by: Luca Ellero <luca.ellero@brickedbrain.com>
>>>>> ---
>>>>>
>>>>>    drivers/mtd/nand/mxs_nand.c |    2 +-
>>>>>    1 file changed, 1 insertion(+), 1 deletion(-)
>>>>>
>>>>> diff --git a/drivers/mtd/nand/mxs_nand.c b/drivers/mtd/nand/mxs_nand.c
>>>>> index 7a064ab..616c9ca 100644
>>>>> --- a/drivers/mtd/nand/mxs_nand.c
>>>>> +++ b/drivers/mtd/nand/mxs_nand.c
>>>>> @@ -305,7 +305,7 @@ static void mxs_nand_cmd_ctrl(struct mtd_info
>>>>> *mtd, int data, unsigned int ctrl)
>>>>>
>>>>>        d->cmd.data =
>>>>>
>>>>>            MXS_DMA_DESC_COMMAND_DMA_READ | MXS_DMA_DESC_IRQ |
>>>>>            MXS_DMA_DESC_CHAIN | MXS_DMA_DESC_DEC_SEM |
>>>>>
>>>>> -        MXS_DMA_DESC_WAIT4END | (3 << MXS_DMA_DESC_PIO_WORDS_OFFSET) |
>>>>> +        MXS_DMA_DESC_WAIT4END | (1 << MXS_DMA_DESC_PIO_WORDS_OFFSET) |
>>>>>
>>>>>            (nand_info->cmd_queue_len << MXS_DMA_DESC_BYTES_OFFSET);
>>>>
>>>> What error or problem does this incorrect setup cause in your case? I'm
>>>> asking since I'm also using this driver in some mx6 system and have not
>>>> seen any issues.
>>>
>>> As far as I can see, it doesn't seem to cause any issue. But, if you
>>> read the iMX6 Reference Manual (chapter 14.2) this field should reflect
>>> the number of PIO_WORDS appended to the DMA command, in this case 1.
>>
>> Okay. I just wanted to check if this patch fixes a real problem that you
>> have experienced. Thanks for the explanation.
>>
>> Reviewed-by: Stefan Roese <sr@denx.de>
>
> The patch does in fact change the behavior such that it no longer clears the
> ECCCTRL and COMPARE registers both on MX28 and on MX6 . Could this have some
> impact?

I'm not sure. The manual doesn't tell much about it. Anyway if we want 
to clear COMPARE and ECCCTRL register, we should at least ensure that 
pio_words 1 and 2 are 0 before executing the DMA chain.

Something like this:

	d->cmd.pio_words[1] = 0;
	d->cmd.pio_words[2] = 0;

What do you think?

regards

-- 
Luca Ellero

E-mail: luca.ellero at brickedbrain.com
Internet: www.brickedbrain.com

[U-Boot] [PATCH] mtd: nand: mxs: fix PIO_WORD number

[Marek Vasut]

On Friday, December 12, 2014 at 04:03:14 PM, Luca Ellero wrote:
> Hi Marek,
> 
> On 12/12/2014 13:58, Marek Vasut wrote:
> > On Friday, December 12, 2014 at 01:43:22 PM, Stefan Roese wrote:
> >> Hi Luca,
> >> 
> >> On 12.12.2014 13:40, Luca Ellero wrote:
> >>>> On 10.12.2014 09:24, Luca Ellero wrote:
> >>>>> There is only one pio_word in this DMA transaction so data field must
> >>>>> be 1.
> >>>>> 
> >>>>> Signed-off-by: Luca Ellero <luca.ellero@brickedbrain.com>
> >>>>> ---
> >>>>> 
> >>>>>    drivers/mtd/nand/mxs_nand.c |    2 +-
> >>>>>    1 file changed, 1 insertion(+), 1 deletion(-)
> >>>>> 
> >>>>> diff --git a/drivers/mtd/nand/mxs_nand.c
> >>>>> b/drivers/mtd/nand/mxs_nand.c index 7a064ab..616c9ca 100644
> >>>>> --- a/drivers/mtd/nand/mxs_nand.c
> >>>>> +++ b/drivers/mtd/nand/mxs_nand.c
> >>>>> @@ -305,7 +305,7 @@ static void mxs_nand_cmd_ctrl(struct mtd_info
> >>>>> *mtd, int data, unsigned int ctrl)
> >>>>> 
> >>>>>        d->cmd.data =
> >>>>>        
> >>>>>            MXS_DMA_DESC_COMMAND_DMA_READ | MXS_DMA_DESC_IRQ |
> >>>>>            MXS_DMA_DESC_CHAIN | MXS_DMA_DESC_DEC_SEM |
> >>>>> 
> >>>>> -        MXS_DMA_DESC_WAIT4END | (3 << MXS_DMA_DESC_PIO_WORDS_OFFSET)
> >>>>> | +        MXS_DMA_DESC_WAIT4END | (1 <<
> >>>>> MXS_DMA_DESC_PIO_WORDS_OFFSET) |
> >>>>> 
> >>>>>            (nand_info->cmd_queue_len << MXS_DMA_DESC_BYTES_OFFSET);
> >>>> 
> >>>> What error or problem does this incorrect setup cause in your case?
> >>>> I'm asking since I'm also using this driver in some mx6 system and
> >>>> have not seen any issues.
> >>> 
> >>> As far as I can see, it doesn't seem to cause any issue. But, if you
> >>> read the iMX6 Reference Manual (chapter 14.2) this field should reflect
> >>> the number of PIO_WORDS appended to the DMA command, in this case 1.
> >> 
> >> Okay. I just wanted to check if this patch fixes a real problem that you
> >> have experienced. Thanks for the explanation.
> >> 
> >> Reviewed-by: Stefan Roese <sr@denx.de>
> > 
> > The patch does in fact change the behavior such that it no longer clears
> > the ECCCTRL and COMPARE registers both on MX28 and on MX6 . Could this
> > have some impact?
> 
> I'm not sure. The manual doesn't tell much about it. Anyway if we want
> to clear COMPARE and ECCCTRL register, we should at least ensure that
> pio_words 1 and 2 are 0 before executing the DMA chain.
> 
> Something like this:
> 
> 	d->cmd.pio_words[1] = 0;
> 	d->cmd.pio_words[2] = 0;
> 
> What do you think?

I believe the descriptor is zeroed out in mxs_nand_return_dma_descs(), though
I admit depending on such behavior is pretty iffy.

The question is, does your patch introduce a side-effect ? My proposal would be 
to schedule the patch for -next and see what happens. I believe the patch would
be just fine and won't break anything.

What do you think ?

Best regards,
Marek Vasut

[U-Boot] [PATCH] mtd: nand: mxs: fix PIO_WORD number

[Luca Ellero]

Hi Marek,

On 13/12/2014 14:12, Marek Vasut wrote:
> On Friday, December 12, 2014 at 04:03:14 PM, Luca Ellero wrote:
>> Hi Marek,
>>
>> On 12/12/2014 13:58, Marek Vasut wrote:
>>> On Friday, December 12, 2014 at 01:43:22 PM, Stefan Roese wrote:
>>>> Hi Luca,
>>>>
>>>> On 12.12.2014 13:40, Luca Ellero wrote:
>>>>>> On 10.12.2014 09:24, Luca Ellero wrote:
>>>>>>> There is only one pio_word in this DMA transaction so data field must
>>>>>>> be 1.
>>>>>>>
>>>>>>> Signed-off-by: Luca Ellero <luca.ellero@brickedbrain.com>
>>>>>>> ---
>>>>>>>
>>>>>>>     drivers/mtd/nand/mxs_nand.c |    2 +-
>>>>>>>     1 file changed, 1 insertion(+), 1 deletion(-)
>>>>>>>
>>>>>>> diff --git a/drivers/mtd/nand/mxs_nand.c
>>>>>>> b/drivers/mtd/nand/mxs_nand.c index 7a064ab..616c9ca 100644
>>>>>>> --- a/drivers/mtd/nand/mxs_nand.c
>>>>>>> +++ b/drivers/mtd/nand/mxs_nand.c
>>>>>>> @@ -305,7 +305,7 @@ static void mxs_nand_cmd_ctrl(struct mtd_info
>>>>>>> *mtd, int data, unsigned int ctrl)
>>>>>>>
>>>>>>>         d->cmd.data =
>>>>>>>
>>>>>>>             MXS_DMA_DESC_COMMAND_DMA_READ | MXS_DMA_DESC_IRQ |
>>>>>>>             MXS_DMA_DESC_CHAIN | MXS_DMA_DESC_DEC_SEM |
>>>>>>>
>>>>>>> -        MXS_DMA_DESC_WAIT4END | (3 << MXS_DMA_DESC_PIO_WORDS_OFFSET)
>>>>>>> | +        MXS_DMA_DESC_WAIT4END | (1 <<
>>>>>>> MXS_DMA_DESC_PIO_WORDS_OFFSET) |
>>>>>>>
>>>>>>>             (nand_info->cmd_queue_len << MXS_DMA_DESC_BYTES_OFFSET);
>>>>>>
>>>>>> What error or problem does this incorrect setup cause in your case?
>>>>>> I'm asking since I'm also using this driver in some mx6 system and
>>>>>> have not seen any issues.
>>>>>
>>>>> As far as I can see, it doesn't seem to cause any issue. But, if you
>>>>> read the iMX6 Reference Manual (chapter 14.2) this field should reflect
>>>>> the number of PIO_WORDS appended to the DMA command, in this case 1.
>>>>
>>>> Okay. I just wanted to check if this patch fixes a real problem that you
>>>> have experienced. Thanks for the explanation.
>>>>
>>>> Reviewed-by: Stefan Roese <sr@denx.de>
>>>
>>> The patch does in fact change the behavior such that it no longer clears
>>> the ECCCTRL and COMPARE registers both on MX28 and on MX6 . Could this
>>> have some impact?
>>
>> I'm not sure. The manual doesn't tell much about it. Anyway if we want
>> to clear COMPARE and ECCCTRL register, we should at least ensure that
>> pio_words 1 and 2 are 0 before executing the DMA chain.
>>
>> Something like this:
>>
>> 	d->cmd.pio_words[1] = 0;
>> 	d->cmd.pio_words[2] = 0;
>>
>> What do you think?
>
> I believe the descriptor is zeroed out in mxs_nand_return_dma_descs(), though
> I admit depending on such behavior is pretty iffy.
>
> The question is, does your patch introduce a side-effect ? My proposal would be
> to schedule the patch for -next and see what happens. I believe the patch would
> be just fine and won't break anything.
>
> What do you think ?

Scheduling the patch for -next it's ok for me.
However there are other two points where pio_words number doesn't 
reflect the pio_words really initiated, one is in mxs_nand_read_buf() 
and one is in mxs_nand_write_buf(). Each one declares 4 pio_words but 
only one is initiated.
I wonder what we should do in this cases.
Regards

-- 
Luca Ellero

E-mail: luca.ellero at brickedbrain.com
Internet: www.brickedbrain.com

[U-Boot] [PATCH] mtd: nand: mxs: fix PIO_WORD number

[Marek Vasut]

On Monday, December 15, 2014 at 09:45:13 AM, Luca Ellero wrote:
> Hi Marek,
> 
> On 13/12/2014 14:12, Marek Vasut wrote:
> > On Friday, December 12, 2014 at 04:03:14 PM, Luca Ellero wrote:
> >> Hi Marek,
> >> 
> >> On 12/12/2014 13:58, Marek Vasut wrote:
> >>> On Friday, December 12, 2014 at 01:43:22 PM, Stefan Roese wrote:
> >>>> Hi Luca,
> >>>> 
> >>>> On 12.12.2014 13:40, Luca Ellero wrote:
> >>>>>> On 10.12.2014 09:24, Luca Ellero wrote:
> >>>>>>> There is only one pio_word in this DMA transaction so data field
> >>>>>>> must be 1.
> >>>>>>> 
> >>>>>>> Signed-off-by: Luca Ellero <luca.ellero@brickedbrain.com>
> >>>>>>> ---
> >>>>>>> 
> >>>>>>>     drivers/mtd/nand/mxs_nand.c |    2 +-
> >>>>>>>     1 file changed, 1 insertion(+), 1 deletion(-)
> >>>>>>> 
> >>>>>>> diff --git a/drivers/mtd/nand/mxs_nand.c
> >>>>>>> b/drivers/mtd/nand/mxs_nand.c index 7a064ab..616c9ca 100644
> >>>>>>> --- a/drivers/mtd/nand/mxs_nand.c
> >>>>>>> +++ b/drivers/mtd/nand/mxs_nand.c
> >>>>>>> @@ -305,7 +305,7 @@ static void mxs_nand_cmd_ctrl(struct mtd_info
> >>>>>>> *mtd, int data, unsigned int ctrl)
> >>>>>>> 
> >>>>>>>         d->cmd.data =
> >>>>>>>         
> >>>>>>>             MXS_DMA_DESC_COMMAND_DMA_READ | MXS_DMA_DESC_IRQ |
> >>>>>>>             MXS_DMA_DESC_CHAIN | MXS_DMA_DESC_DEC_SEM |
> >>>>>>> 
> >>>>>>> -        MXS_DMA_DESC_WAIT4END | (3 <<
> >>>>>>> MXS_DMA_DESC_PIO_WORDS_OFFSET)
> >>>>>>> 
> >>>>>>> | +        MXS_DMA_DESC_WAIT4END | (1 <<
> >>>>>>> 
> >>>>>>> MXS_DMA_DESC_PIO_WORDS_OFFSET) |
> >>>>>>> 
> >>>>>>>             (nand_info->cmd_queue_len <<
> >>>>>>>             MXS_DMA_DESC_BYTES_OFFSET);
> >>>>>> 
> >>>>>> What error or problem does this incorrect setup cause in your case?
> >>>>>> I'm asking since I'm also using this driver in some mx6 system and
> >>>>>> have not seen any issues.
> >>>>> 
> >>>>> As far as I can see, it doesn't seem to cause any issue. But, if you
> >>>>> read the iMX6 Reference Manual (chapter 14.2) this field should
> >>>>> reflect the number of PIO_WORDS appended to the DMA command, in this
> >>>>> case 1.
> >>>> 
> >>>> Okay. I just wanted to check if this patch fixes a real problem that
> >>>> you have experienced. Thanks for the explanation.
> >>>> 
> >>>> Reviewed-by: Stefan Roese <sr@denx.de>
> >>> 
> >>> The patch does in fact change the behavior such that it no longer
> >>> clears the ECCCTRL and COMPARE registers both on MX28 and on MX6 .
> >>> Could this have some impact?
> >> 
> >> I'm not sure. The manual doesn't tell much about it. Anyway if we want
> >> to clear COMPARE and ECCCTRL register, we should at least ensure that
> >> pio_words 1 and 2 are 0 before executing the DMA chain.
> >> 
> >> Something like this:
> >> 	d->cmd.pio_words[1] = 0;
> >> 	d->cmd.pio_words[2] = 0;
> >> 
> >> What do you think?
> > 
> > I believe the descriptor is zeroed out in mxs_nand_return_dma_descs(),
> > though I admit depending on such behavior is pretty iffy.
> > 
> > The question is, does your patch introduce a side-effect ? My proposal
> > would be to schedule the patch for -next and see what happens. I believe
> > the patch would be just fine and won't break anything.
> > 
> > What do you think ?
> 
> Scheduling the patch for -next it's ok for me.
> However there are other two points where pio_words number doesn't
> reflect the pio_words really initiated, one is in mxs_nand_read_buf()
> and one is in mxs_nand_write_buf(). Each one declares 4 pio_words but
> only one is initiated.
> I wonder what we should do in this cases.

You can fix those as well. I recall that all this goop came from the original 
(2.6.35) GPMI NAND driver, which is likely where all those bugs came from as 
well.

Thank you!

[U-Boot] [PATCH] mtd: nand: mxs: fix PIO_WORD number

[Luca Ellero]

On 15/12/2014 12:14, Marek Vasut wrote:
> On Monday, December 15, 2014 at 09:45:13 AM, Luca Ellero wrote:
>> Hi Marek,
>>
>> On 13/12/2014 14:12, Marek Vasut wrote:
>>> On Friday, December 12, 2014 at 04:03:14 PM, Luca Ellero wrote:
>>>> Hi Marek,
>>>>
>>>> On 12/12/2014 13:58, Marek Vasut wrote:
>>>>> On Friday, December 12, 2014 at 01:43:22 PM, Stefan Roese wrote:
>>>>>> Hi Luca,
>>>>>>
>>>>>> On 12.12.2014 13:40, Luca Ellero wrote:
>>>>>>>> On 10.12.2014 09:24, Luca Ellero wrote:
>>>>>>>>> There is only one pio_word in this DMA transaction so data field
>>>>>>>>> must be 1.
>>>>>>>>>
>>>>>>>>> Signed-off-by: Luca Ellero <luca.ellero@brickedbrain.com>
>>>>>>>>> ---
>>>>>>>>>
>>>>>>>>>      drivers/mtd/nand/mxs_nand.c |    2 +-
>>>>>>>>>      1 file changed, 1 insertion(+), 1 deletion(-)
>>>>>>>>>
>>>>>>>>> diff --git a/drivers/mtd/nand/mxs_nand.c
>>>>>>>>> b/drivers/mtd/nand/mxs_nand.c index 7a064ab..616c9ca 100644
>>>>>>>>> --- a/drivers/mtd/nand/mxs_nand.c
>>>>>>>>> +++ b/drivers/mtd/nand/mxs_nand.c
>>>>>>>>> @@ -305,7 +305,7 @@ static void mxs_nand_cmd_ctrl(struct mtd_info
>>>>>>>>> *mtd, int data, unsigned int ctrl)
>>>>>>>>>
>>>>>>>>>          d->cmd.data =
>>>>>>>>>
>>>>>>>>>              MXS_DMA_DESC_COMMAND_DMA_READ | MXS_DMA_DESC_IRQ |
>>>>>>>>>              MXS_DMA_DESC_CHAIN | MXS_DMA_DESC_DEC_SEM |
>>>>>>>>>
>>>>>>>>> -        MXS_DMA_DESC_WAIT4END | (3 <<
>>>>>>>>> MXS_DMA_DESC_PIO_WORDS_OFFSET)
>>>>>>>>>
>>>>>>>>> | +        MXS_DMA_DESC_WAIT4END | (1 <<
>>>>>>>>>
>>>>>>>>> MXS_DMA_DESC_PIO_WORDS_OFFSET) |
>>>>>>>>>
>>>>>>>>>              (nand_info->cmd_queue_len <<
>>>>>>>>>              MXS_DMA_DESC_BYTES_OFFSET);
>>>>>>>>
>>>>>>>> What error or problem does this incorrect setup cause in your case?
>>>>>>>> I'm asking since I'm also using this driver in some mx6 system and
>>>>>>>> have not seen any issues.
>>>>>>>
>>>>>>> As far as I can see, it doesn't seem to cause any issue. But, if you
>>>>>>> read the iMX6 Reference Manual (chapter 14.2) this field should
>>>>>>> reflect the number of PIO_WORDS appended to the DMA command, in this
>>>>>>> case 1.
>>>>>>
>>>>>> Okay. I just wanted to check if this patch fixes a real problem that
>>>>>> you have experienced. Thanks for the explanation.
>>>>>>
>>>>>> Reviewed-by: Stefan Roese <sr@denx.de>
>>>>>
>>>>> The patch does in fact change the behavior such that it no longer
>>>>> clears the ECCCTRL and COMPARE registers both on MX28 and on MX6 .
>>>>> Could this have some impact?
>>>>
>>>> I'm not sure. The manual doesn't tell much about it. Anyway if we want
>>>> to clear COMPARE and ECCCTRL register, we should at least ensure that
>>>> pio_words 1 and 2 are 0 before executing the DMA chain.
>>>>
>>>> Something like this:
>>>> 	d->cmd.pio_words[1] = 0;
>>>> 	d->cmd.pio_words[2] = 0;
>>>>
>>>> What do you think?
>>>
>>> I believe the descriptor is zeroed out in mxs_nand_return_dma_descs(),
>>> though I admit depending on such behavior is pretty iffy.
>>>
>>> The question is, does your patch introduce a side-effect ? My proposal
>>> would be to schedule the patch for -next and see what happens. I believe
>>> the patch would be just fine and won't break anything.
>>>
>>> What do you think ?
>>
>> Scheduling the patch for -next it's ok for me.
>> However there are other two points where pio_words number doesn't
>> reflect the pio_words really initiated, one is in mxs_nand_read_buf()
>> and one is in mxs_nand_write_buf(). Each one declares 4 pio_words but
>> only one is initiated.
>> I wonder what we should do in this cases.
>
> You can fix those as well. I recall that all this goop came from the original
> (2.6.35) GPMI NAND driver, which is likely where all those bugs came from as
> well.
>
> Thank you!
>

OK, I will send a patch to fix them.
Regards

-- 
Luca Ellero

E-mail: luca.ellero at brickedbrain.com
Internet: www.brickedbrain.com

[U-Boot] [PATCH] mtd: nand: mxs: fix PIO_WORD number

[Marek Vasut]

On Tuesday, December 16, 2014 at 09:06:34 AM, Luca Ellero wrote:
> On 15/12/2014 12:14, Marek Vasut wrote:
> > On Monday, December 15, 2014 at 09:45:13 AM, Luca Ellero wrote:
> >> Hi Marek,
> >> 
> >> On 13/12/2014 14:12, Marek Vasut wrote:
> >>> On Friday, December 12, 2014 at 04:03:14 PM, Luca Ellero wrote:
> >>>> Hi Marek,
> >>>> 
> >>>> On 12/12/2014 13:58, Marek Vasut wrote:
> >>>>> On Friday, December 12, 2014 at 01:43:22 PM, Stefan Roese wrote:
> >>>>>> Hi Luca,
> >>>>>> 
> >>>>>> On 12.12.2014 13:40, Luca Ellero wrote:
> >>>>>>>> On 10.12.2014 09:24, Luca Ellero wrote:
> >>>>>>>>> There is only one pio_word in this DMA transaction so data field
> >>>>>>>>> must be 1.
> >>>>>>>>> 
> >>>>>>>>> Signed-off-by: Luca Ellero <luca.ellero@brickedbrain.com>
> >>>>>>>>> ---
> >>>>>>>>> 
> >>>>>>>>>      drivers/mtd/nand/mxs_nand.c |    2 +-
> >>>>>>>>>      1 file changed, 1 insertion(+), 1 deletion(-)
> >>>>>>>>> 
> >>>>>>>>> diff --git a/drivers/mtd/nand/mxs_nand.c
> >>>>>>>>> b/drivers/mtd/nand/mxs_nand.c index 7a064ab..616c9ca 100644
> >>>>>>>>> --- a/drivers/mtd/nand/mxs_nand.c
> >>>>>>>>> +++ b/drivers/mtd/nand/mxs_nand.c
> >>>>>>>>> @@ -305,7 +305,7 @@ static void mxs_nand_cmd_ctrl(struct mtd_info
> >>>>>>>>> *mtd, int data, unsigned int ctrl)
> >>>>>>>>> 
> >>>>>>>>>          d->cmd.data =
> >>>>>>>>>          
> >>>>>>>>>              MXS_DMA_DESC_COMMAND_DMA_READ | MXS_DMA_DESC_IRQ |
> >>>>>>>>>              MXS_DMA_DESC_CHAIN | MXS_DMA_DESC_DEC_SEM |
> >>>>>>>>> 
> >>>>>>>>> -        MXS_DMA_DESC_WAIT4END | (3 <<
> >>>>>>>>> MXS_DMA_DESC_PIO_WORDS_OFFSET)
> >>>>>>>>> 
> >>>>>>>>> | +        MXS_DMA_DESC_WAIT4END | (1 <<
> >>>>>>>>> 
> >>>>>>>>> MXS_DMA_DESC_PIO_WORDS_OFFSET) |
> >>>>>>>>> 
> >>>>>>>>>              (nand_info->cmd_queue_len <<
> >>>>>>>>>              MXS_DMA_DESC_BYTES_OFFSET);
> >>>>>>>> 
> >>>>>>>> What error or problem does this incorrect setup cause in your
> >>>>>>>> case? I'm asking since I'm also using this driver in some mx6
> >>>>>>>> system and have not seen any issues.
> >>>>>>> 
> >>>>>>> As far as I can see, it doesn't seem to cause any issue. But, if
> >>>>>>> you read the iMX6 Reference Manual (chapter 14.2) this field
> >>>>>>> should reflect the number of PIO_WORDS appended to the DMA
> >>>>>>> command, in this case 1.
> >>>>>> 
> >>>>>> Okay. I just wanted to check if this patch fixes a real problem that
> >>>>>> you have experienced. Thanks for the explanation.
> >>>>>> 
> >>>>>> Reviewed-by: Stefan Roese <sr@denx.de>
> >>>>> 
> >>>>> The patch does in fact change the behavior such that it no longer
> >>>>> clears the ECCCTRL and COMPARE registers both on MX28 and on MX6 .
> >>>>> Could this have some impact?
> >>>> 
> >>>> I'm not sure. The manual doesn't tell much about it. Anyway if we want
> >>>> to clear COMPARE and ECCCTRL register, we should at least ensure that
> >>>> pio_words 1 and 2 are 0 before executing the DMA chain.
> >>>> 
> >>>> Something like this:
> >>>> 	d->cmd.pio_words[1] = 0;
> >>>> 	d->cmd.pio_words[2] = 0;
> >>>> 
> >>>> What do you think?
> >>> 
> >>> I believe the descriptor is zeroed out in mxs_nand_return_dma_descs(),
> >>> though I admit depending on such behavior is pretty iffy.
> >>> 
> >>> The question is, does your patch introduce a side-effect ? My proposal
> >>> would be to schedule the patch for -next and see what happens. I
> >>> believe the patch would be just fine and won't break anything.
> >>> 
> >>> What do you think ?
> >> 
> >> Scheduling the patch for -next it's ok for me.
> >> However there are other two points where pio_words number doesn't
> >> reflect the pio_words really initiated, one is in mxs_nand_read_buf()
> >> and one is in mxs_nand_write_buf(). Each one declares 4 pio_words but
> >> only one is initiated.
> >> I wonder what we should do in this cases.
> > 
> > You can fix those as well. I recall that all this goop came from the
> > original (2.6.35) GPMI NAND driver, which is likely where all those bugs
> > came from as well.
> > 
> > Thank you!
> 
> OK, I will send a patch to fix them.

Thanks!

[U-Boot] [PATCH] mtd: nand: mxs: fix PIO_WORD number

[Stefano Babic]

Hi Luca,

On 16/12/2014 09:06, Luca Ellero wrote:

>>> Scheduling the patch for -next it's ok for me.
>>> However there are other two points where pio_words number doesn't
>>> reflect the pio_words really initiated, one is in mxs_nand_read_buf()
>>> and one is in mxs_nand_write_buf(). Each one declares 4 pio_words but
>>> only one is initiated.
>>> I wonder what we should do in this cases.
>>
>> You can fix those as well. I recall that all this goop came from the
>> original
>> (2.6.35) GPMI NAND driver, which is likely where all those bugs came
>> from as
>> well.
>>
>> Thank you!
>>
> 
> OK, I will send a patch to fix them.

Do you plan to send a V2 patch for fixing all the issues at once ?

Best regards,
Stefano Babic

-- 
=====================================================================
DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: +49-8142-66989-53 Fax: +49-8142-66989-80 Email: sbabic at denx.de
=====================================================================

[U-Boot] [PATCH] mtd: nand: mxs: fix PIO_WORD number

[Luca Ellero]

On 10/02/2015 14:14, Stefano Babic wrote:
> Hi Luca,
>
> On 16/12/2014 09:06, Luca Ellero wrote:
>
>>>> Scheduling the patch for -next it's ok for me.
>>>> However there are other two points where pio_words number doesn't
>>>> reflect the pio_words really initiated, one is in mxs_nand_read_buf()
>>>> and one is in mxs_nand_write_buf(). Each one declares 4 pio_words but
>>>> only one is initiated.
>>>> I wonder what we should do in this cases.
>>>
>>> You can fix those as well. I recall that all this goop came from the
>>> original
>>> (2.6.35) GPMI NAND driver, which is likely where all those bugs came
>>> from as
>>> well.
>>>
>>> Thank you!
>>>
>>
>> OK, I will send a patch to fix them.
>
> Do you plan to send a V2 patch for fixing all the issues at once ?
>
> Best regards,
> Stefano Babic
>

Hi Stefano,
yes, I can send a patch with all the fixes, that's fine.
I plan to send it tomorrow.
Regards
Luca


-- 
Luca Ellero

E-mail: luca.ellero at brickedbrain.com
Internet: www.brickedbrain.com

[U-Boot] [PATCH] mtd: nand: mxs: fix PIO_WORD number

[Marek Vasut]

On Tuesday, February 10, 2015 at 04:18:12 PM, Luca Ellero wrote:
> On 10/02/2015 14:14, Stefano Babic wrote:
> > Hi Luca,
> > 
> > On 16/12/2014 09:06, Luca Ellero wrote:
> >>>> Scheduling the patch for -next it's ok for me.
> >>>> However there are other two points where pio_words number doesn't
> >>>> reflect the pio_words really initiated, one is in mxs_nand_read_buf()
> >>>> and one is in mxs_nand_write_buf(). Each one declares 4 pio_words but
> >>>> only one is initiated.
> >>>> I wonder what we should do in this cases.
> >>> 
> >>> You can fix those as well. I recall that all this goop came from the
> >>> original
> >>> (2.6.35) GPMI NAND driver, which is likely where all those bugs came
> >>> from as
> >>> well.
> >>> 
> >>> Thank you!
> >> 
> >> OK, I will send a patch to fix them.
> > 
> > Do you plan to send a V2 patch for fixing all the issues at once ?
> > 
> > Best regards,
> > Stefano Babic
> 
> Hi Stefano,
> yes, I can send a patch with all the fixes, that's fine.
> I plan to send it tomorrow.

Thank you :)

Best regards,
Marek Vasut