[PATCH] ARM: at91: dts: sama5d3/sama5d4: reduce NFC command registers memory region

[PATCH] ARM: at91: dts: sama5d3/sama5d4: reduce NFC command registers memory region

[Josh Wu]

To get NFC status, we need to read the NFC command registers, which is a
256M memory mapping address. To check the status, you just read such
address from NFC command registers.
For example, to check NFCBUSY (bit 27), you need to read 0x08000000
(bit 27 is set to 1) of the NFC command register.
If you want to check NFCBUSY (bit 27) and NFCWR (bit 26) in same time,
you need to read 0x0c000000 (bit 27 and bit 26 are set to 1).

But mapping such huge memory address only for multiple NFC status check
is not very economic.

The economic way is we check the NFC status one bit a time, then we don't
have to mapping such huge address.

Now we reduce the memory mapping from 256M to 128M+4 (include 0x08000000),
the only difference is NFCBUSY (bit 27) status. You cannot check NFCBUSY
bit with other NFC status bit.

Since current atmel_nand driver check the NFCBUSY status without combine
other bits, so this change (reduce 256M to 128M+4) will not be harmful.

Signed-off-by: Josh Wu <josh.wu-AIFe0yeh4nAAvxtiuMwx3w@public.gmane.org>

---

 arch/arm/boot/dts/sama5d3.dtsi | 2 +-
 arch/arm/boot/dts/sama5d4.dtsi | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/arm/boot/dts/sama5d3.dtsi b/arch/arm/boot/dts/sama5d3.dtsi
index d701ddd..d243732 100644
--- a/arch/arm/boot/dts/sama5d3.dtsi
+++ b/arch/arm/boot/dts/sama5d3.dtsi
@@ -1426,7 +1426,7 @@
 				#address-cells = <1>;
 				#size-cells = <1>;
 				reg = <
-					0x70000000 0x10000000	/* NFC Command Registers */
+					0x70000000 0x08000004	/* NFC Command Registers */
 					0xffffc000 0x00000070	/* NFC HSMC regs */
 					0x00200000 0x00100000	/* NFC SRAM banks */
 					>;
diff --git a/arch/arm/boot/dts/sama5d4.dtsi b/arch/arm/boot/dts/sama5d4.dtsi
index 0a2477f..05b096b 100644
--- a/arch/arm/boot/dts/sama5d4.dtsi
+++ b/arch/arm/boot/dts/sama5d4.dtsi
@@ -288,7 +288,7 @@
 				#address-cells = <1>;
 				#size-cells = <1>;
 				reg = <
-					0x90000000 0x10000000	/* NFC Command Registers */
+					0x90000000 0x08000004	/* NFC Command Registers */
 					0xfc05c000 0x00000070	/* NFC HSMC regs */
 					0x00100000 0x00100000	/* NFC SRAM banks */
                                          >;
-- 
1.9.1

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Re: [PATCH] ARM: at91: dts: sama5d3/sama5d4: reduce NFC command registers memory region

[Boris Brezillon]

Hi Josh,

On Thu, 15 Jan 2015 15:08:03 +0800
Josh Wu <josh.wu-AIFe0yeh4nAAvxtiuMwx3w@public.gmane.org> wrote:

> To get NFC status, we need to read the NFC command registers, which is a
> 256M memory mapping address. To check the status, you just read such
> address from NFC command registers.
> For example, to check NFCBUSY (bit 27), you need to read 0x08000000
> (bit 27 is set to 1) of the NFC command register.
> If you want to check NFCBUSY (bit 27) and NFCWR (bit 26) in same time,
> you need to read 0x0c000000 (bit 27 and bit 26 are set to 1).

Are NFCBUSY and NFCWR found in NFCDATA_STATUS and those found in HSMC_SR
representing the same thing.
If they are, I think you can just use HSMC_SR instead of NFCDATA_STATUS
to check the status [1] and drop the last bit in the NFC Command
Resgiters range.

> 
> But mapping such huge memory address only for multiple NFC status check
> is not very economic.
> 
> The economic way is we check the NFC status one bit a time, then we don't
> have to mapping such huge address.
> 
> Now we reduce the memory mapping from 256M to 128M+4 (include 0x08000000),
> the only difference is NFCBUSY (bit 27) status. You cannot check NFCBUSY
> bit with other NFC status bit.
> 
> Since current atmel_nand driver check the NFCBUSY status without combine
> other bits, so this change (reduce 256M to 128M+4) will not be harmful.
> 
> Signed-off-by: Josh Wu <josh.wu-AIFe0yeh4nAAvxtiuMwx3w@public.gmane.org>
> 
> ---
> 
>  arch/arm/boot/dts/sama5d3.dtsi | 2 +-
>  arch/arm/boot/dts/sama5d4.dtsi | 2 +-
>  2 files changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/arm/boot/dts/sama5d3.dtsi b/arch/arm/boot/dts/sama5d3.dtsi
> index d701ddd..d243732 100644
> --- a/arch/arm/boot/dts/sama5d3.dtsi
> +++ b/arch/arm/boot/dts/sama5d3.dtsi
> @@ -1426,7 +1426,7 @@
>  				#address-cells = <1>;
>  				#size-cells = <1>;
>  				reg = <
> -					0x70000000 0x10000000	/* NFC Command Registers */
> +					0x70000000 0x08000004	/* NFC Command Registers */

This would give the following range:

					0x70000000 0x08000000


Best Regards,

Boris

[1]http://code.bulix.org/2noozv-87724


-- 
Boris Brezillon, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com
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Re: [PATCH] ARM: at91: dts: sama5d3/sama5d4: reduce NFC command registers memory region

[Josh Wu]

Hi， Boris

Thanks for the review.

On 1/15/2015 4:45 PM, Boris Brezillon wrote:
> Hi Josh,
>
> On Thu, 15 Jan 2015 15:08:03 +0800
> Josh Wu <josh.wu-AIFe0yeh4nAAvxtiuMwx3w@public.gmane.org> wrote:
>
>> To get NFC status, we need to read the NFC command registers, which is a
>> 256M memory mapping address. To check the status, you just read such
>> address from NFC command registers.
>> For example, to check NFCBUSY (bit 27), you need to read 0x08000000
>> (bit 27 is set to 1) of the NFC command register.
>> If you want to check NFCBUSY (bit 27) and NFCWR (bit 26) in same time,
>> you need to read 0x0c000000 (bit 27 and bit 26 are set to 1).
> Are NFCBUSY and NFCWR found in NFCDATA_STATUS and those found in HSMC_SR
> representing the same thing.
yes. it is. I just check with IP team. The NFCBUSY of NFCDATA_STATUS is 
also refer to NFC_BUSY of HSMC_SR.

> If they are, I think you can just use HSMC_SR instead of NFCDATA_STATUS
> to check the status [1] and drop the last bit in the NFC Command
> Resgiters range.
Thank you. your code works (just need some typo change).
I want to send [1] code with your signed-off and my acked to mtd list.
Is it okay for you?

>
>> But mapping such huge memory address only for multiple NFC status check
>> is not very economic.
>>
>> The economic way is we check the NFC status one bit a time, then we don't
>> have to mapping such huge address.
>>
>> Now we reduce the memory mapping from 256M to 128M+4 (include 0x08000000),
>> the only difference is NFCBUSY (bit 27) status. You cannot check NFCBUSY
>> bit with other NFC status bit.
>>
>> Since current atmel_nand driver check the NFCBUSY status without combine
>> other bits, so this change (reduce 256M to 128M+4) will not be harmful.
>>
>> Signed-off-by: Josh Wu <josh.wu-AIFe0yeh4nAAvxtiuMwx3w@public.gmane.org>
>>
>> ---
>>
>>   arch/arm/boot/dts/sama5d3.dtsi | 2 +-
>>   arch/arm/boot/dts/sama5d4.dtsi | 2 +-
>>   2 files changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/arch/arm/boot/dts/sama5d3.dtsi b/arch/arm/boot/dts/sama5d3.dtsi
>> index d701ddd..d243732 100644
>> --- a/arch/arm/boot/dts/sama5d3.dtsi
>> +++ b/arch/arm/boot/dts/sama5d3.dtsi
>> @@ -1426,7 +1426,7 @@
>>   				#address-cells = <1>;
>>   				#size-cells = <1>;
>>   				reg = <
>> -					0x70000000 0x10000000	/* NFC Command Registers */
>> +					0x70000000 0x08000004	/* NFC Command Registers */
> This would give the following range:
>
> 					0x70000000 0x08000000
This is also right if we apply above code change.

So after above patch for mtd list is accepted I'll send out the dts 
changes patch.

>
>
> Best Regards,
>
> Boris
>
> [1]http://code.bulix.org/2noozv-87724
>
>
Best Regards,
Josh Wu
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Re: [PATCH] ARM: at91: dts: sama5d3/sama5d4: reduce NFC command registers memory region

[Boris Brezillon]

Hi Josh,

On Thu, 15 Jan 2015 17:59:15 +0800
Josh Wu <josh.wu-AIFe0yeh4nAAvxtiuMwx3w@public.gmane.org> wrote:

> Hi， Boris
> 
> Thanks for the review.
> 
> On 1/15/2015 4:45 PM, Boris Brezillon wrote:
> > Hi Josh,
> >
> > On Thu, 15 Jan 2015 15:08:03 +0800
> > Josh Wu <josh.wu-AIFe0yeh4nAAvxtiuMwx3w@public.gmane.org> wrote:
> >
> >> To get NFC status, we need to read the NFC command registers, which is a
> >> 256M memory mapping address. To check the status, you just read such
> >> address from NFC command registers.
> >> For example, to check NFCBUSY (bit 27), you need to read 0x08000000
> >> (bit 27 is set to 1) of the NFC command register.
> >> If you want to check NFCBUSY (bit 27) and NFCWR (bit 26) in same time,
> >> you need to read 0x0c000000 (bit 27 and bit 26 are set to 1).
> > Are NFCBUSY and NFCWR found in NFCDATA_STATUS and those found in HSMC_SR
> > representing the same thing.
> yes. it is. I just check with IP team. The NFCBUSY of NFCDATA_STATUS is 
> also refer to NFC_BUSY of HSMC_SR.
> 
> > If they are, I think you can just use HSMC_SR instead of NFCDATA_STATUS
> > to check the status [1] and drop the last bit in the NFC Command
> > Resgiters range.
> Thank you. your code works (just need some typo change).
> I want to send [1] code with your signed-off and my acked to mtd list.
> Is it okay for you?

Sure, no problem.



-- 
Boris Brezillon, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com
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Re: [PATCH] ARM: at91: dts: sama5d3/sama5d4: reduce NFC command registers memory region

[Nicolas Ferre]

Le 15/01/2015 11:05, Boris Brezillon a écrit :
> Hi Josh,
> 
> On Thu, 15 Jan 2015 17:59:15 +0800
> Josh Wu <josh.wu-AIFe0yeh4nAAvxtiuMwx3w@public.gmane.org> wrote:
> 
>> Hi， Boris
>>
>> Thanks for the review.
>>
>> On 1/15/2015 4:45 PM, Boris Brezillon wrote:
>>> Hi Josh,
>>>
>>> On Thu, 15 Jan 2015 15:08:03 +0800
>>> Josh Wu <josh.wu-AIFe0yeh4nAAvxtiuMwx3w@public.gmane.org> wrote:
>>>
>>>> To get NFC status, we need to read the NFC command registers, which is a
>>>> 256M memory mapping address. To check the status, you just read such
>>>> address from NFC command registers.
>>>> For example, to check NFCBUSY (bit 27), you need to read 0x08000000
>>>> (bit 27 is set to 1) of the NFC command register.
>>>> If you want to check NFCBUSY (bit 27) and NFCWR (bit 26) in same time,
>>>> you need to read 0x0c000000 (bit 27 and bit 26 are set to 1).
>>> Are NFCBUSY and NFCWR found in NFCDATA_STATUS and those found in HSMC_SR
>>> representing the same thing.
>> yes. it is. I just check with IP team. The NFCBUSY of NFCDATA_STATUS is 
>> also refer to NFC_BUSY of HSMC_SR.
>>
>>> If they are, I think you can just use HSMC_SR instead of NFCDATA_STATUS
>>> to check the status [1] and drop the last bit in the NFC Command
>>> Resgiters range.
>> Thank you. your code works (just need some typo change).
>> I want to send [1] code with your signed-off and my acked to mtd list.
>> Is it okay for you?
> 
> Sure, no problem.

Hi Josh,

What is the status of this patch set?

Bye,
-- 
Nicolas Ferre
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Re: [PATCH] ARM: at91: dts: sama5d3/sama5d4: reduce NFC command registers memory region

[Josh Wu]

Hi, Nicolas

On 3/4/2015 11:19 PM, Nicolas Ferre wrote:
> Le 15/01/2015 11:05, Boris Brezillon a écrit :
>> Hi Josh,
>>
>> On Thu, 15 Jan 2015 17:59:15 +0800
>> Josh Wu <josh.wu-AIFe0yeh4nAAvxtiuMwx3w@public.gmane.org> wrote:
>>
>>> Hi， Boris
>>>
>>> Thanks for the review.
>>>
>>> On 1/15/2015 4:45 PM, Boris Brezillon wrote:
>>>> Hi Josh,
>>>>
>>>> On Thu, 15 Jan 2015 15:08:03 +0800
>>>> Josh Wu <josh.wu-AIFe0yeh4nAAvxtiuMwx3w@public.gmane.org> wrote:
>>>>
>>>>> To get NFC status, we need to read the NFC command registers, which is a
>>>>> 256M memory mapping address. To check the status, you just read such
>>>>> address from NFC command registers.
>>>>> For example, to check NFCBUSY (bit 27), you need to read 0x08000000
>>>>> (bit 27 is set to 1) of the NFC command register.
>>>>> If you want to check NFCBUSY (bit 27) and NFCWR (bit 26) in same time,
>>>>> you need to read 0x0c000000 (bit 27 and bit 26 are set to 1).
>>>> Are NFCBUSY and NFCWR found in NFCDATA_STATUS and those found in HSMC_SR
>>>> representing the same thing.
>>> yes. it is. I just check with IP team. The NFCBUSY of NFCDATA_STATUS is
>>> also refer to NFC_BUSY of HSMC_SR.
>>>
>>>> If they are, I think you can just use HSMC_SR instead of NFCDATA_STATUS
>>>> to check the status [1] and drop the last bit in the NFC Command
>>>> Resgiters range.
>>> Thank you. your code works (just need some typo change).
>>> I want to send [1] code with your signed-off and my acked to mtd list.
>>> Is it okay for you?
>> Sure, no problem.
> Hi Josh,
>
> What is the status of this patch set?

The v2 of this patch is sent. But it's not taken by Brain.
I just ping Brain yesterday. Check the v2 patch here:
http://patchwork.ozlabs.org/patch/431752/

Best Regards,
Josh Wu
>
> Bye,

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Re: [PATCH] ARM: at91: dts: sama5d3/sama5d4: reduce NFC command registers memory region

[Nicolas Ferre]

Le 05/03/2015 02:52, Josh Wu a écrit :
> Hi, Nicolas
> 
> On 3/4/2015 11:19 PM, Nicolas Ferre wrote:
>> Le 15/01/2015 11:05, Boris Brezillon a écrit :
>>> Hi Josh,
>>>
>>> On Thu, 15 Jan 2015 17:59:15 +0800
>>> Josh Wu <josh.wu-AIFe0yeh4nAAvxtiuMwx3w@public.gmane.org> wrote:
>>>
>>>> Hi， Boris
>>>>
>>>> Thanks for the review.
>>>>
>>>> On 1/15/2015 4:45 PM, Boris Brezillon wrote:
>>>>> Hi Josh,
>>>>>
>>>>> On Thu, 15 Jan 2015 15:08:03 +0800
>>>>> Josh Wu <josh.wu-AIFe0yeh4nAAvxtiuMwx3w@public.gmane.org> wrote:
>>>>>
>>>>>> To get NFC status, we need to read the NFC command registers, which is a
>>>>>> 256M memory mapping address. To check the status, you just read such
>>>>>> address from NFC command registers.
>>>>>> For example, to check NFCBUSY (bit 27), you need to read 0x08000000
>>>>>> (bit 27 is set to 1) of the NFC command register.
>>>>>> If you want to check NFCBUSY (bit 27) and NFCWR (bit 26) in same time,
>>>>>> you need to read 0x0c000000 (bit 27 and bit 26 are set to 1).
>>>>> Are NFCBUSY and NFCWR found in NFCDATA_STATUS and those found in HSMC_SR
>>>>> representing the same thing.
>>>> yes. it is. I just check with IP team. The NFCBUSY of NFCDATA_STATUS is
>>>> also refer to NFC_BUSY of HSMC_SR.
>>>>
>>>>> If they are, I think you can just use HSMC_SR instead of NFCDATA_STATUS
>>>>> to check the status [1] and drop the last bit in the NFC Command
>>>>> Resgiters range.
>>>> Thank you. your code works (just need some typo change).
>>>> I want to send [1] code with your signed-off and my acked to mtd list.
>>>> Is it okay for you?
>>> Sure, no problem.
>> Hi Josh,
>>
>> What is the status of this patch set?
> 
> The v2 of this patch is sent. But it's not taken by Brain.
> I just ping Brain yesterday. Check the v2 patch here:
> http://patchwork.ozlabs.org/patch/431752/

Ok, thanks for the information Josh.

Bye,
-- 
Nicolas Ferre
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