diff mbox series

arm: mach-k3: am6_init: Prioritize MSMC traffic over DDR in NAVSS Northbridge

Message ID 20200130080503.28657-1-rogerq@ti.com
State Accepted
Commit 6887f8e00b821a3af02da207c85ba61c286dcc3c
Headers show
Series arm: mach-k3: am6_init: Prioritize MSMC traffic over DDR in NAVSS Northbridge | expand

Commit Message

Roger Quadros Jan. 30, 2020, 8:05 a.m. UTC 
NB0 is bridge to SRAM and NB1 is bridge to DDR.

To ensure that SRAM transfers are not stalled due to
delays during DDR refreshes, SRAM traffic should be higher
priority (threadmap=2) than DDR traffic (threadmap=0).

This patch does just that.

This is required to fix ICSSG TX lock-ups due to delays in
MSMC transfers due to incorrect Northbridge configuration.

Signed-off-by: Roger Quadros <rogerq at ti.com>
Acked-by: Andrew F. Davis <afd at ti.com>
Acked-by: Tomi Valkeinen <tomi.valkeinen at ti.com>
Acked-by: Benoit Parrot <bparrot at ti.com>
---
 arch/arm/mach-k3/am6_init.c                  | 14 ++++++++++++++
 arch/arm/mach-k3/include/mach/am6_hardware.h |  7 +++++++
 2 files changed, 21 insertions(+)

Comments

Jan Kiszka July 28, 2021, 9:10 a.m. UTC | #1 
On 30.01.20 09:05, Roger Quadros wrote:
> NB0 is bridge to SRAM and NB1 is bridge to DDR.

> 

> To ensure that SRAM transfers are not stalled due to

> delays during DDR refreshes, SRAM traffic should be higher

> priority (threadmap=2) than DDR traffic (threadmap=0).

> 

> This patch does just that.

> 

> This is required to fix ICSSG TX lock-ups due to delays in

> MSMC transfers due to incorrect Northbridge configuration.

> 

> Signed-off-by: Roger Quadros <rogerq@ti.com>

> Acked-by: Andrew F. Davis <afd@ti.com>

> Acked-by: Tomi Valkeinen <tomi.valkeinen@ti.com>

> Acked-by: Benoit Parrot <bparrot@ti.com>

> ---

>  arch/arm/mach-k3/am6_init.c                  | 14 ++++++++++++++

>  arch/arm/mach-k3/include/mach/am6_hardware.h |  7 +++++++

>  2 files changed, 21 insertions(+)

> 

> diff --git a/arch/arm/mach-k3/am6_init.c b/arch/arm/mach-k3/am6_init.c

> index 8d107b870b..9379b95bdb 100644

> --- a/arch/arm/mach-k3/am6_init.c

> +++ b/arch/arm/mach-k3/am6_init.c

> @@ -86,6 +86,18 @@ static void store_boot_index_from_rom(void)

>  	bootindex = *(u32 *)(CONFIG_SYS_K3_BOOT_PARAM_TABLE_INDEX);

>  }

>  

> +static void setup_am654_navss_northbridge(void)

> +{

> +	/*

> +	 * NB0 is bridge to SRAM and NB1 is bridge to DDR.

> +	 * To ensure that SRAM transfers are not stalled due to

> +	 * delays during DDR refreshes, SRAM traffic should be higher

> +	 * priority (threadmap=2) than DDR traffic (threadmap=0).

> +	 */

> +	writel(0x2, NAVSS0_NBSS_NB0_CFG_BASE + NAVSS_NBSS_THREADMAP);

> +	writel(0x0, NAVSS0_NBSS_NB1_CFG_BASE + NAVSS_NBSS_THREADMAP);

> +}

> +

>  void board_init_f(ulong dummy)

>  {

>  #if defined(CONFIG_K3_LOAD_SYSFW) || defined(CONFIG_K3_AM654_DDRSS)

> @@ -101,6 +113,8 @@ void board_init_f(ulong dummy)

>  	/* Make all control module registers accessible */

>  	ctrl_mmr_unlock();

>  

> +	setup_am654_navss_northbridge();

> +

>  #ifdef CONFIG_CPU_V7R

>  	disable_linefill_optimization();

>  	setup_k3_mpu_regions();

> diff --git a/arch/arm/mach-k3/include/mach/am6_hardware.h b/arch/arm/mach-k3/include/mach/am6_hardware.h

> index 6df7631545..45a5b31c52 100644

> --- a/arch/arm/mach-k3/include/mach/am6_hardware.h

> +++ b/arch/arm/mach-k3/include/mach/am6_hardware.h

> @@ -47,4 +47,11 @@

>  /* MCU SCRATCHPAD usage */

>  #define TI_SRAM_SCRATCH_BOARD_EEPROM_START CONFIG_SYS_K3_MCU_SCRATCHPAD_BASE

>  

> +/* NAVSS Northbridge config */

> +#define	NAVSS0_NBSS_NB0_CFG_BASE	0x03802000

> +#define	NAVSS0_NBSS_NB1_CFG_BASE	0x03803000

> +

> +#define	NAVSS_NBSS_PID		0x0

> +#define	NAVSS_NBSS_THREADMAP	0x10

> +

>  #endif /* __ASM_ARCH_AM6_HARDWARE_H */

> 


This was never merged, not even commented on (only apparently rejected
in patchwork) - but it is crucial as we now found out:

prueth will quickly stall when these priorities are not applied, at
least with SR1.0-based AM65x designs. And you probably know what else
could go wrong. Please clarify and merge, possibly reducing the scope to
SR1.0 if you can confirm that SR2.0 cannot be affected by design (I can
only say this based on few practical experiments here).

If it was good for several TI SDK releases by now, at least something
similar should be good for upstream as well, I believe.

Thanks,
Jan

-- 
Siemens AG, T RDA IOT
Corporate Competence Center Embedded Linux
Jan Kiszka Sept. 2, 2021, 6:36 a.m. UTC | #2 
On 28.07.21 11:10, Jan Kiszka wrote:
> On 30.01.20 09:05, Roger Quadros wrote:

>> NB0 is bridge to SRAM and NB1 is bridge to DDR.

>>

>> To ensure that SRAM transfers are not stalled due to

>> delays during DDR refreshes, SRAM traffic should be higher

>> priority (threadmap=2) than DDR traffic (threadmap=0).

>>

>> This patch does just that.

>>

>> This is required to fix ICSSG TX lock-ups due to delays in

>> MSMC transfers due to incorrect Northbridge configuration.

>>

>> Signed-off-by: Roger Quadros <rogerq@ti.com>

>> Acked-by: Andrew F. Davis <afd@ti.com>

>> Acked-by: Tomi Valkeinen <tomi.valkeinen@ti.com>

>> Acked-by: Benoit Parrot <bparrot@ti.com>

>> ---

>>  arch/arm/mach-k3/am6_init.c                  | 14 ++++++++++++++

>>  arch/arm/mach-k3/include/mach/am6_hardware.h |  7 +++++++

>>  2 files changed, 21 insertions(+)

>>

>> diff --git a/arch/arm/mach-k3/am6_init.c b/arch/arm/mach-k3/am6_init.c

>> index 8d107b870b..9379b95bdb 100644

>> --- a/arch/arm/mach-k3/am6_init.c

>> +++ b/arch/arm/mach-k3/am6_init.c

>> @@ -86,6 +86,18 @@ static void store_boot_index_from_rom(void)

>>  	bootindex = *(u32 *)(CONFIG_SYS_K3_BOOT_PARAM_TABLE_INDEX);

>>  }

>>  

>> +static void setup_am654_navss_northbridge(void)

>> +{

>> +	/*

>> +	 * NB0 is bridge to SRAM and NB1 is bridge to DDR.

>> +	 * To ensure that SRAM transfers are not stalled due to

>> +	 * delays during DDR refreshes, SRAM traffic should be higher

>> +	 * priority (threadmap=2) than DDR traffic (threadmap=0).

>> +	 */

>> +	writel(0x2, NAVSS0_NBSS_NB0_CFG_BASE + NAVSS_NBSS_THREADMAP);

>> +	writel(0x0, NAVSS0_NBSS_NB1_CFG_BASE + NAVSS_NBSS_THREADMAP);

>> +}

>> +

>>  void board_init_f(ulong dummy)

>>  {

>>  #if defined(CONFIG_K3_LOAD_SYSFW) || defined(CONFIG_K3_AM654_DDRSS)

>> @@ -101,6 +113,8 @@ void board_init_f(ulong dummy)

>>  	/* Make all control module registers accessible */

>>  	ctrl_mmr_unlock();

>>  

>> +	setup_am654_navss_northbridge();

>> +

>>  #ifdef CONFIG_CPU_V7R

>>  	disable_linefill_optimization();

>>  	setup_k3_mpu_regions();

>> diff --git a/arch/arm/mach-k3/include/mach/am6_hardware.h b/arch/arm/mach-k3/include/mach/am6_hardware.h

>> index 6df7631545..45a5b31c52 100644

>> --- a/arch/arm/mach-k3/include/mach/am6_hardware.h

>> +++ b/arch/arm/mach-k3/include/mach/am6_hardware.h

>> @@ -47,4 +47,11 @@

>>  /* MCU SCRATCHPAD usage */

>>  #define TI_SRAM_SCRATCH_BOARD_EEPROM_START CONFIG_SYS_K3_MCU_SCRATCHPAD_BASE

>>  

>> +/* NAVSS Northbridge config */

>> +#define	NAVSS0_NBSS_NB0_CFG_BASE	0x03802000

>> +#define	NAVSS0_NBSS_NB1_CFG_BASE	0x03803000

>> +

>> +#define	NAVSS_NBSS_PID		0x0

>> +#define	NAVSS_NBSS_THREADMAP	0x10

>> +

>>  #endif /* __ASM_ARCH_AM6_HARDWARE_H */

>>

> 

> This was never merged, not even commented on (only apparently rejected

> in patchwork) - but it is crucial as we now found out:

> 

> prueth will quickly stall when these priorities are not applied, at

> least with SR1.0-based AM65x designs. And you probably know what else

> could go wrong. Please clarify and merge, possibly reducing the scope to

> SR1.0 if you can confirm that SR2.0 cannot be affected by design (I can

> only say this based on few practical experiments here).

> 

> If it was good for several TI SDK releases by now, at least something

> similar should be good for upstream as well, I believe.

> 


Ping. We need at least some confirmation on what is actually needed.
Then, if you do not like to add it to the generic path, it would be easy
for us to carry it in the IOT2050 board init only - with the appropriate
condition check.

Jan

-- 
Siemens AG, T RDA IOT
Corporate Competence Center Embedded Linux
Jan Kiszka Sept. 7, 2021, 7:41 p.m. UTC | #3 
On 02.09.21 08:36, Jan Kiszka wrote:
> On 28.07.21 11:10, Jan Kiszka wrote:

>> On 30.01.20 09:05, Roger Quadros wrote:

>>> NB0 is bridge to SRAM and NB1 is bridge to DDR.

>>>

>>> To ensure that SRAM transfers are not stalled due to

>>> delays during DDR refreshes, SRAM traffic should be higher

>>> priority (threadmap=2) than DDR traffic (threadmap=0).

>>>

>>> This patch does just that.

>>>

>>> This is required to fix ICSSG TX lock-ups due to delays in

>>> MSMC transfers due to incorrect Northbridge configuration.

>>>

>>> Signed-off-by: Roger Quadros <rogerq@ti.com>

>>> Acked-by: Andrew F. Davis <afd@ti.com>

>>> Acked-by: Tomi Valkeinen <tomi.valkeinen@ti.com>

>>> Acked-by: Benoit Parrot <bparrot@ti.com>

>>> ---

>>>  arch/arm/mach-k3/am6_init.c                  | 14 ++++++++++++++

>>>  arch/arm/mach-k3/include/mach/am6_hardware.h |  7 +++++++

>>>  2 files changed, 21 insertions(+)

>>>

>>> diff --git a/arch/arm/mach-k3/am6_init.c b/arch/arm/mach-k3/am6_init.c

>>> index 8d107b870b..9379b95bdb 100644

>>> --- a/arch/arm/mach-k3/am6_init.c

>>> +++ b/arch/arm/mach-k3/am6_init.c

>>> @@ -86,6 +86,18 @@ static void store_boot_index_from_rom(void)

>>>  	bootindex = *(u32 *)(CONFIG_SYS_K3_BOOT_PARAM_TABLE_INDEX);

>>>  }

>>>  

>>> +static void setup_am654_navss_northbridge(void)

>>> +{

>>> +	/*

>>> +	 * NB0 is bridge to SRAM and NB1 is bridge to DDR.

>>> +	 * To ensure that SRAM transfers are not stalled due to

>>> +	 * delays during DDR refreshes, SRAM traffic should be higher

>>> +	 * priority (threadmap=2) than DDR traffic (threadmap=0).

>>> +	 */

>>> +	writel(0x2, NAVSS0_NBSS_NB0_CFG_BASE + NAVSS_NBSS_THREADMAP);

>>> +	writel(0x0, NAVSS0_NBSS_NB1_CFG_BASE + NAVSS_NBSS_THREADMAP);

>>> +}

>>> +

>>>  void board_init_f(ulong dummy)

>>>  {

>>>  #if defined(CONFIG_K3_LOAD_SYSFW) || defined(CONFIG_K3_AM654_DDRSS)

>>> @@ -101,6 +113,8 @@ void board_init_f(ulong dummy)

>>>  	/* Make all control module registers accessible */

>>>  	ctrl_mmr_unlock();

>>>  

>>> +	setup_am654_navss_northbridge();

>>> +

>>>  #ifdef CONFIG_CPU_V7R

>>>  	disable_linefill_optimization();

>>>  	setup_k3_mpu_regions();

>>> diff --git a/arch/arm/mach-k3/include/mach/am6_hardware.h b/arch/arm/mach-k3/include/mach/am6_hardware.h

>>> index 6df7631545..45a5b31c52 100644

>>> --- a/arch/arm/mach-k3/include/mach/am6_hardware.h

>>> +++ b/arch/arm/mach-k3/include/mach/am6_hardware.h

>>> @@ -47,4 +47,11 @@

>>>  /* MCU SCRATCHPAD usage */

>>>  #define TI_SRAM_SCRATCH_BOARD_EEPROM_START CONFIG_SYS_K3_MCU_SCRATCHPAD_BASE

>>>  

>>> +/* NAVSS Northbridge config */

>>> +#define	NAVSS0_NBSS_NB0_CFG_BASE	0x03802000

>>> +#define	NAVSS0_NBSS_NB1_CFG_BASE	0x03803000

>>> +

>>> +#define	NAVSS_NBSS_PID		0x0

>>> +#define	NAVSS_NBSS_THREADMAP	0x10

>>> +

>>>  #endif /* __ASM_ARCH_AM6_HARDWARE_H */

>>>

>>

>> This was never merged, not even commented on (only apparently rejected

>> in patchwork) - but it is crucial as we now found out:

>>

>> prueth will quickly stall when these priorities are not applied, at

>> least with SR1.0-based AM65x designs. And you probably know what else

>> could go wrong. Please clarify and merge, possibly reducing the scope to

>> SR1.0 if you can confirm that SR2.0 cannot be affected by design (I can

>> only say this based on few practical experiments here).

>>

>> If it was good for several TI SDK releases by now, at least something

>> similar should be good for upstream as well, I believe.

>>

> 

> Ping. We need at least some confirmation on what is actually needed.

> Then, if you do not like to add it to the generic path, it would be easy

> for us to carry it in the IOT2050 board init only - with the appropriate

> condition check.

> 


Did some more experiments on SR2 silicon, and while I'm not seeing
stalls without this patch there, iperf tests with prueth show high retry
rates and, thus, about 10% worse throughput. So it seems to be required
for newer silicon as well.

Jan

-- 
Siemens AG, T RDA IOT
Corporate Competence Center Embedded Linux
Tom Rini Sept. 7, 2021, 8:27 p.m. UTC | #4 
On Tue, Sep 07, 2021 at 09:41:23PM +0200, Jan Kiszka wrote:
> On 02.09.21 08:36, Jan Kiszka wrote:

> > On 28.07.21 11:10, Jan Kiszka wrote:

> >> On 30.01.20 09:05, Roger Quadros wrote:

> >>> NB0 is bridge to SRAM and NB1 is bridge to DDR.

> >>>

> >>> To ensure that SRAM transfers are not stalled due to

> >>> delays during DDR refreshes, SRAM traffic should be higher

> >>> priority (threadmap=2) than DDR traffic (threadmap=0).

> >>>

> >>> This patch does just that.

> >>>

> >>> This is required to fix ICSSG TX lock-ups due to delays in

> >>> MSMC transfers due to incorrect Northbridge configuration.

> >>>

> >>> Signed-off-by: Roger Quadros <rogerq@ti.com>

> >>> Acked-by: Andrew F. Davis <afd@ti.com>

> >>> Acked-by: Tomi Valkeinen <tomi.valkeinen@ti.com>

> >>> Acked-by: Benoit Parrot <bparrot@ti.com>

> >>> ---

> >>>  arch/arm/mach-k3/am6_init.c                  | 14 ++++++++++++++

> >>>  arch/arm/mach-k3/include/mach/am6_hardware.h |  7 +++++++

> >>>  2 files changed, 21 insertions(+)

> >>>

> >>> diff --git a/arch/arm/mach-k3/am6_init.c b/arch/arm/mach-k3/am6_init.c

> >>> index 8d107b870b..9379b95bdb 100644

> >>> --- a/arch/arm/mach-k3/am6_init.c

> >>> +++ b/arch/arm/mach-k3/am6_init.c

> >>> @@ -86,6 +86,18 @@ static void store_boot_index_from_rom(void)

> >>>  	bootindex = *(u32 *)(CONFIG_SYS_K3_BOOT_PARAM_TABLE_INDEX);

> >>>  }

> >>>  

> >>> +static void setup_am654_navss_northbridge(void)

> >>> +{

> >>> +	/*

> >>> +	 * NB0 is bridge to SRAM and NB1 is bridge to DDR.

> >>> +	 * To ensure that SRAM transfers are not stalled due to

> >>> +	 * delays during DDR refreshes, SRAM traffic should be higher

> >>> +	 * priority (threadmap=2) than DDR traffic (threadmap=0).

> >>> +	 */

> >>> +	writel(0x2, NAVSS0_NBSS_NB0_CFG_BASE + NAVSS_NBSS_THREADMAP);

> >>> +	writel(0x0, NAVSS0_NBSS_NB1_CFG_BASE + NAVSS_NBSS_THREADMAP);

> >>> +}

> >>> +

> >>>  void board_init_f(ulong dummy)

> >>>  {

> >>>  #if defined(CONFIG_K3_LOAD_SYSFW) || defined(CONFIG_K3_AM654_DDRSS)

> >>> @@ -101,6 +113,8 @@ void board_init_f(ulong dummy)

> >>>  	/* Make all control module registers accessible */

> >>>  	ctrl_mmr_unlock();

> >>>  

> >>> +	setup_am654_navss_northbridge();

> >>> +

> >>>  #ifdef CONFIG_CPU_V7R

> >>>  	disable_linefill_optimization();

> >>>  	setup_k3_mpu_regions();

> >>> diff --git a/arch/arm/mach-k3/include/mach/am6_hardware.h b/arch/arm/mach-k3/include/mach/am6_hardware.h

> >>> index 6df7631545..45a5b31c52 100644

> >>> --- a/arch/arm/mach-k3/include/mach/am6_hardware.h

> >>> +++ b/arch/arm/mach-k3/include/mach/am6_hardware.h

> >>> @@ -47,4 +47,11 @@

> >>>  /* MCU SCRATCHPAD usage */

> >>>  #define TI_SRAM_SCRATCH_BOARD_EEPROM_START CONFIG_SYS_K3_MCU_SCRATCHPAD_BASE

> >>>  

> >>> +/* NAVSS Northbridge config */

> >>> +#define	NAVSS0_NBSS_NB0_CFG_BASE	0x03802000

> >>> +#define	NAVSS0_NBSS_NB1_CFG_BASE	0x03803000

> >>> +

> >>> +#define	NAVSS_NBSS_PID		0x0

> >>> +#define	NAVSS_NBSS_THREADMAP	0x10

> >>> +

> >>>  #endif /* __ASM_ARCH_AM6_HARDWARE_H */

> >>>

> >>

> >> This was never merged, not even commented on (only apparently rejected

> >> in patchwork) - but it is crucial as we now found out:

> >>

> >> prueth will quickly stall when these priorities are not applied, at

> >> least with SR1.0-based AM65x designs. And you probably know what else

> >> could go wrong. Please clarify and merge, possibly reducing the scope to

> >> SR1.0 if you can confirm that SR2.0 cannot be affected by design (I can

> >> only say this based on few practical experiments here).

> >>

> >> If it was good for several TI SDK releases by now, at least something

> >> similar should be good for upstream as well, I believe.

> >>

> > 

> > Ping. We need at least some confirmation on what is actually needed.

> > Then, if you do not like to add it to the generic path, it would be easy

> > for us to carry it in the IOT2050 board init only - with the appropriate

> > condition check.

> 

> Did some more experiments on SR2 silicon, and while I'm not seeing

> stalls without this patch there, iperf tests with prueth show high retry

> rates and, thus, about 10% worse throughput. So it seems to be required

> for newer silicon as well.


At this point, I'd really appreciate it if someone from within TI can
chime in here as I expect someone must suspect something here, thanks!

-- 
Tom
Nishanth Menon Sept. 8, 2021, 4:22 a.m. UTC | #5 
On 16:27-20210907, Tom Rini wrote:
> On Tue, Sep 07, 2021 at 09:41:23PM +0200, Jan Kiszka wrote:

> > On 02.09.21 08:36, Jan Kiszka wrote:

> > > On 28.07.21 11:10, Jan Kiszka wrote:

> > >> On 30.01.20 09:05, Roger Quadros wrote:


[...]

> > >>>  #endif /* __ASM_ARCH_AM6_HARDWARE_H */

> > >>>

> > >>

> > >> This was never merged, not even commented on (only apparently rejected

> > >> in patchwork) - but it is crucial as we now found out:

> > >>

> > >> prueth will quickly stall when these priorities are not applied, at

> > >> least with SR1.0-based AM65x designs. And you probably know what else

> > >> could go wrong. Please clarify and merge, possibly reducing the scope to

> > >> SR1.0 if you can confirm that SR2.0 cannot be affected by design (I can

> > >> only say this based on few practical experiments here).

> > >>

> > >> If it was good for several TI SDK releases by now, at least something

> > >> similar should be good for upstream as well, I believe.

> > >>

> > > 

> > > Ping. We need at least some confirmation on what is actually needed.

> > > Then, if you do not like to add it to the generic path, it would be easy

> > > for us to carry it in the IOT2050 board init only - with the appropriate

> > > condition check.

> > 

> > Did some more experiments on SR2 silicon, and while I'm not seeing

> > stalls without this patch there, iperf tests with prueth show high retry

> > rates and, thus, about 10% worse throughput. So it seems to be required

> > for newer silicon as well.

> 

> At this point, I'd really appreciate it if someone from within TI can

> chime in here as I expect someone must suspect something here, thanks!


Here are some internal discussion highlights:


This is critical to provide deterministic access latency to MSMC from
ICSSG, it applies to all AM65 silicon revisions.

- is this errata or use-case specific settings?
Incorrect reset values, should've been static and setup as in the patch.

- what SoCs are affected (am64, J721e)?
AM65x only

- if this configuration applied will/might it affect on other use-cases (mostly
 multi-media related)?
No. This will only effect traffic taking advantage of the 2 ports to
MSMC and mapping to independent threads inside MSMC, one for SRAM and
one for DDR bound traffic.

In short, the patch is valid, we should be able to apply this
consistently on AM65x SoCs independent of the platform.


Hope this helps?

-- 
Regards,
Nishanth Menon
Key (0xDDB5849D1736249D) / Fingerprint: F8A2 8693 54EB 8232 17A3  1A34 DDB5 849D 1736 249D
Jan Kiszka Sept. 8, 2021, 10:24 a.m. UTC | #6 
On 08.09.21 06:22, Nishanth Menon wrote:
> On 16:27-20210907, Tom Rini wrote:

>> On Tue, Sep 07, 2021 at 09:41:23PM +0200, Jan Kiszka wrote:

>>> On 02.09.21 08:36, Jan Kiszka wrote:

>>>> On 28.07.21 11:10, Jan Kiszka wrote:

>>>>> On 30.01.20 09:05, Roger Quadros wrote:

> 

> [...]

> 

>>>>>>  #endif /* __ASM_ARCH_AM6_HARDWARE_H */

>>>>>>

>>>>>

>>>>> This was never merged, not even commented on (only apparently rejected

>>>>> in patchwork) - but it is crucial as we now found out:

>>>>>

>>>>> prueth will quickly stall when these priorities are not applied, at

>>>>> least with SR1.0-based AM65x designs. And you probably know what else

>>>>> could go wrong. Please clarify and merge, possibly reducing the scope to

>>>>> SR1.0 if you can confirm that SR2.0 cannot be affected by design (I can

>>>>> only say this based on few practical experiments here).

>>>>>

>>>>> If it was good for several TI SDK releases by now, at least something

>>>>> similar should be good for upstream as well, I believe.

>>>>>

>>>>

>>>> Ping. We need at least some confirmation on what is actually needed.

>>>> Then, if you do not like to add it to the generic path, it would be easy

>>>> for us to carry it in the IOT2050 board init only - with the appropriate

>>>> condition check.

>>>

>>> Did some more experiments on SR2 silicon, and while I'm not seeing

>>> stalls without this patch there, iperf tests with prueth show high retry

>>> rates and, thus, about 10% worse throughput. So it seems to be required

>>> for newer silicon as well.

>>

>> At this point, I'd really appreciate it if someone from within TI can

>> chime in here as I expect someone must suspect something here, thanks!

> 

> Here are some internal discussion highlights:

> 

> 

> This is critical to provide deterministic access latency to MSMC from

> ICSSG, it applies to all AM65 silicon revisions.

> 

> - is this errata or use-case specific settings?

> Incorrect reset values, should've been static and setup as in the patch.

> 

> - what SoCs are affected (am64, J721e)?

> AM65x only

> 

> - if this configuration applied will/might it affect on other use-cases (mostly

>  multi-media related)?

> No. This will only effect traffic taking advantage of the 2 ports to

> MSMC and mapping to independent threads inside MSMC, one for SRAM and

> one for DDR bound traffic.

> 

> In short, the patch is valid, we should be able to apply this

> consistently on AM65x SoCs independent of the platform.

> 

> 

> Hope this helps?

> 


Thanks a lot!

Who will augment its description and push this again? I have a rebased
version [1] at least, slightly polished, but my commit log is possibly
not optimal yet.

Jan

[1]
https://github.com/siemens/u-boot/commit/2cf7a2fc14b82b12aa06152dbecc694691801fee

-- 
Siemens AG, T RDA IOT
Corporate Competence Center Embedded Linux
Nishanth Menon Sept. 8, 2021, 8:30 p.m. UTC | #7 
On 12:24-20210908, Jan Kiszka wrote:
[...]
> Thanks a lot!

> 

> Who will augment its description and push this again? I have a rebased

> version [1] at least, slightly polished, but my commit log is possibly

> not optimal yet.



Done. https://patchwork.ozlabs.org/project/uboot/patch/20210908202859.10942-1-nm@ti.com/

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Regards,
Nishanth Menon
Key (0xDDB5849D1736249D) / Fingerprint: F8A2 8693 54EB 8232 17A3  1A34 DDB5 849D 1736 249D
diff mbox series

Patch

diff --git a/arch/arm/mach-k3/am6_init.c b/arch/arm/mach-k3/am6_init.c
index 8d107b870b..9379b95bdb 100644
--- a/arch/arm/mach-k3/am6_init.c
+++ b/arch/arm/mach-k3/am6_init.c
@@ -86,6 +86,18 @@  static void store_boot_index_from_rom(void)
 	bootindex = *(u32 *)(CONFIG_SYS_K3_BOOT_PARAM_TABLE_INDEX);
 }
 
+static void setup_am654_navss_northbridge(void)
+{
+	/*
+	 * NB0 is bridge to SRAM and NB1 is bridge to DDR.
+	 * To ensure that SRAM transfers are not stalled due to
+	 * delays during DDR refreshes, SRAM traffic should be higher
+	 * priority (threadmap=2) than DDR traffic (threadmap=0).
+	 */
+	writel(0x2, NAVSS0_NBSS_NB0_CFG_BASE + NAVSS_NBSS_THREADMAP);
+	writel(0x0, NAVSS0_NBSS_NB1_CFG_BASE + NAVSS_NBSS_THREADMAP);
+}
+
 void board_init_f(ulong dummy)
 {
 #if defined(CONFIG_K3_LOAD_SYSFW) || defined(CONFIG_K3_AM654_DDRSS)
@@ -101,6 +113,8 @@  void board_init_f(ulong dummy)
 	/* Make all control module registers accessible */
 	ctrl_mmr_unlock();
 
+	setup_am654_navss_northbridge();
+
 #ifdef CONFIG_CPU_V7R
 	disable_linefill_optimization();
 	setup_k3_mpu_regions();
diff --git a/arch/arm/mach-k3/include/mach/am6_hardware.h b/arch/arm/mach-k3/include/mach/am6_hardware.h
index 6df7631545..45a5b31c52 100644
--- a/arch/arm/mach-k3/include/mach/am6_hardware.h
+++ b/arch/arm/mach-k3/include/mach/am6_hardware.h
@@ -47,4 +47,11 @@ 
 /* MCU SCRATCHPAD usage */
 #define TI_SRAM_SCRATCH_BOARD_EEPROM_START CONFIG_SYS_K3_MCU_SCRATCHPAD_BASE
 
+/* NAVSS Northbridge config */
+#define	NAVSS0_NBSS_NB0_CFG_BASE	0x03802000
+#define	NAVSS0_NBSS_NB1_CFG_BASE	0x03803000
+
+#define	NAVSS_NBSS_PID		0x0
+#define	NAVSS_NBSS_THREADMAP	0x10
+
 #endif /* __ASM_ARCH_AM6_HARDWARE_H */