MCAN Registers Discrepancy

MCAN Registers Discrepancy

[Franklin S Cooper Jr]

Hi,

When looking at the latest versions of the MCAN user manual it seems
that there is a discrepancy between the various BTR_XX_MASK and
BTR_XX_SHIFT values. For example BTR_TSEG2_MASK is set to 0xF and
BTR_TSEG2_SHIFT is 4. However, based on page 21 of the latest version of
the MCAN User Manual NTSEG2 starts at bit 0. Therefore, it should have a
shift value of 0. Also it is a 7 bit field so its mask should be 0x7F. I
see similar issues with FBTR_XXX_MASK values.

So the original driver mentioned it was based on rev version 3.1.0 of
the User Manual while the latest version publicly available is 3.2.12.
Since I don't see any current users of this driver in upstream I am
unsure if this is just a bug in the code or if the current values are
correct for older versions of the IP.

Does anyone have a copy of this older document available that they can
share? Or at the very least verify that the current values were correct
in older revisions of the MCAN IP? I need to make updates to the drivers
but I want to avoid breaking things for other people.

Latest version of the MCAN User Manual can be found at:
http://www.bosch-semiconductors.de/media/automotive_electronics/pdf_2/ipmodules_3/m_can_m_ttcan_1/mcan_users_manual_v3212.pdf

Re: MCAN Registers Discrepancy

[Mario Hüttel]

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Hello,

you are right. There are/were some incosistencies in the values.

However, the driver used them correctly. The driver version you

talk about is not entirely compatible with the user manual you provided.


I wrote some patches back in April which add support for the newer M_CAN

versions up to 3.2.X:

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/log/drivers/net/can/m_can

These should work as intended.

Before, the driver could only handle IP versions 3.0.X.


Mario



On 06/28/2017 11:49 PM, Franklin S Cooper Jr wrote:
> Hi,
>
> When looking at the latest versions of the MCAN user manual it seems
> that there is a discrepancy between the various BTR_XX_MASK and
> BTR_XX_SHIFT values. For example BTR_TSEG2_MASK is set to 0xF and
> BTR_TSEG2_SHIFT is 4. However, based on page 21 of the latest version of
> the MCAN User Manual NTSEG2 starts at bit 0. Therefore, it should have a
> shift value of 0. Also it is a 7 bit field so its mask should be 0x7F. I
> see similar issues with FBTR_XXX_MASK values.
>
> So the original driver mentioned it was based on rev version 3.1.0 of
> the User Manual while the latest version publicly available is 3.2.12.
> Since I don't see any current users of this driver in upstream I am
> unsure if this is just a bug in the code or if the current values are
> correct for older versions of the IP.
>
> Does anyone have a copy of this older document available that they can
> share? Or at the very least verify that the current values were correct
> in older revisions of the MCAN IP? I need to make updates to the drivers
> but I want to avoid breaking things for other people.
>
> Latest version of the MCAN User Manual can be found at:
> http://www.bosch-semiconductors.de/media/automotive_electronics/pdf_2/ipmodules_3/m_can_m_ttcan_1/mcan_users_manual_v3212.pdf
> --
> To unsubscribe from this list: send the line "unsubscribe linux-can" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html



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Re: MCAN Registers Discrepancy

[Franklin S Cooper Jr]

Hi Mario,

On 06/29/2017 09:52 AM, Mario Hüttel wrote:
> Hello,
> 
> you are right. There are/were some incosistencies in the values.
> 
> However, the driver used them correctly. The driver version you
> 
> talk about is not entirely compatible with the user manual you provided.
> 
> 
> I wrote some patches back in April which add support for the newer M_CAN
> 
> versions up to 3.2.X:
> 
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/log/drivers/net/can/m_can
> 
> These should work as intended.
> 
> Before, the driver could only handle IP versions 3.0.X.

It was my mistake. Looks like the branch I was working off of wasn't
updated for a bit. Your patches contain exactly what I found was needed.

> 
> 
> Mario
> 
> 
> 
> On 06/28/2017 11:49 PM, Franklin S Cooper Jr wrote:
>> Hi,
>>
>> When looking at the latest versions of the MCAN user manual it seems
>> that there is a discrepancy between the various BTR_XX_MASK and
>> BTR_XX_SHIFT values. For example BTR_TSEG2_MASK is set to 0xF and
>> BTR_TSEG2_SHIFT is 4. However, based on page 21 of the latest version of
>> the MCAN User Manual NTSEG2 starts at bit 0. Therefore, it should have a
>> shift value of 0. Also it is a 7 bit field so its mask should be 0x7F. I
>> see similar issues with FBTR_XXX_MASK values.
>>
>> So the original driver mentioned it was based on rev version 3.1.0 of
>> the User Manual while the latest version publicly available is 3.2.12.
>> Since I don't see any current users of this driver in upstream I am
>> unsure if this is just a bug in the code or if the current values are
>> correct for older versions of the IP.
>>
>> Does anyone have a copy of this older document available that they can
>> share? Or at the very least verify that the current values were correct
>> in older revisions of the MCAN IP? I need to make updates to the drivers
>> but I want to avoid breaking things for other people.
>>
>> Latest version of the MCAN User Manual can be found at:
>> http://www.bosch-semiconductors.de/media/automotive_electronics/pdf_2/ipmodules_3/m_can_m_ttcan_1/mcan_users_manual_v3212.pdf
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-can" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> 
> 

Re: MCAN Registers Discrepancy

[Oliver Hartkopp]

Hi Franklin,

I added Mario in CC as he provided the latest updates to the M_CAN 
driver and the multi IP revision support.

As you are not the first one asking for the 'older' M_CAN IP revision 
user manuals I uploaded my formerly downloaded manuals here:

https://github.com/hartkopp/M_CAN-User-Manual-History

Best regards,
Oliver

On 06/28/2017 11:49 PM, Franklin S Cooper Jr wrote:
> When looking at the latest versions of the MCAN user manual it seems
> that there is a discrepancy between the various BTR_XX_MASK and
> BTR_XX_SHIFT values. For example BTR_TSEG2_MASK is set to 0xF and
> BTR_TSEG2_SHIFT is 4. However, based on page 21 of the latest version of
> the MCAN User Manual NTSEG2 starts at bit 0. Therefore, it should have a
> shift value of 0. Also it is a 7 bit field so its mask should be 0x7F. I
> see similar issues with FBTR_XXX_MASK values.
>
> So the original driver mentioned it was based on rev version 3.1.0 of
> the User Manual while the latest version publicly available is 3.2.12.
> Since I don't see any current users of this driver in upstream I am
> unsure if this is just a bug in the code or if the current values are
> correct for older versions of the IP.
>
> Does anyone have a copy of this older document available that they can
> share? Or at the very least verify that the current values were correct
> in older revisions of the MCAN IP? I need to make updates to the drivers
> but I want to avoid breaking things for other people.
>
> Latest version of the MCAN User Manual can be found at:
> http://www.bosch-semiconductors.de/media/automotive_electronics/pdf_2/ipmodules_3/m_can_m_ttcan_1/mcan_users_manual_v3212.pdf
>

Re: MCAN Registers Discrepancy

[Franklin S Cooper Jr]

Hi Oliver,

On 06/29/2017 12:38 PM, Oliver Hartkopp wrote:
> Hi Franklin,
> 
> I added Mario in CC as he provided the latest updates to the M_CAN
> driver and the multi IP revision support.
> 
> As you are not the first one asking for the 'older' M_CAN IP revision
> user manuals I uploaded my formerly downloaded manuals here:
> 
> https://github.com/hartkopp/M_CAN-User-Manual-History

It seems I missed Mario's changes since he fixed the problem I
mentioned. But thanks for sharing these documents. It helps alot.
> 
> Best regards,
> Oliver
> 
> On 06/28/2017 11:49 PM, Franklin S Cooper Jr wrote:
>> When looking at the latest versions of the MCAN user manual it seems
>> that there is a discrepancy between the various BTR_XX_MASK and
>> BTR_XX_SHIFT values. For example BTR_TSEG2_MASK is set to 0xF and
>> BTR_TSEG2_SHIFT is 4. However, based on page 21 of the latest version of
>> the MCAN User Manual NTSEG2 starts at bit 0. Therefore, it should have a
>> shift value of 0. Also it is a 7 bit field so its mask should be 0x7F. I
>> see similar issues with FBTR_XXX_MASK values.
>>
>> So the original driver mentioned it was based on rev version 3.1.0 of
>> the User Manual while the latest version publicly available is 3.2.12.
>> Since I don't see any current users of this driver in upstream I am
>> unsure if this is just a bug in the code or if the current values are
>> correct for older versions of the IP.
>>
>> Does anyone have a copy of this older document available that they can
>> share? Or at the very least verify that the current values were correct
>> in older revisions of the MCAN IP? I need to make updates to the drivers
>> but I want to avoid breaking things for other people.
>>
>> Latest version of the MCAN User Manual can be found at:
>> http://www.bosch-semiconductors.de/media/automotive_electronics/pdf_2/ipmodules_3/m_can_m_ttcan_1/mcan_users_manual_v3212.pdf
>>
>>