[PATCH master] Revert "ARM: beaglebone: init MPU speed to 800Mhz"

[PATCH master] Revert "ARM: beaglebone: init MPU speed to 800Mhz"

[Ahmad Fatoum]

Commit 130c7d6715e9 ("ARM: beaglebone: init MPU speed to 800Mhz") causes
warm reboot from within Linux v5.14.0 to no longer succeed.
barebox MLO is entered, but hangs. Reset from within barebox is
unaffected.
This can be reproduced using DistroKit 949c5ef2b9a6 ("v7a: barebox:
version bump v2021.08.0 → v2021.11.0") on a Beaglebone Black.
Until that's figured out, revert the commit; functional reboot is more
important than the quicker boot up.

This reverts commit 130c7d6715e932a1e0b3e026fea97f700ab33ea9.

Fixes: 130c7d6715e9 ("ARM: beaglebone: init MPU speed to 800Mhz")
Reported-by: arwie # IRC
Cc: Marc Reilly <marc@cpdesign.com.au>
Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
---
 arch/arm/boards/beaglebone/lowlevel.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm/boards/beaglebone/lowlevel.c b/arch/arm/boards/beaglebone/lowlevel.c
index 31211448f5e8..91d143e4150b 100644
--- a/arch/arm/boards/beaglebone/lowlevel.c
+++ b/arch/arm/boards/beaglebone/lowlevel.c
@@ -126,7 +126,7 @@ static noinline int beaglebone_sram_init(void)
 
 	/* Setup the PLLs and the clocks for the peripherals */
 	if (is_beaglebone_black()) {
-		am33xx_pll_init(MPUPLL_M_800, DDRPLL_M_400);
+		am33xx_pll_init(MPUPLL_M_500, DDRPLL_M_400);
 		am335x_sdram_init(0x18B, &ddr3_cmd_ctrl, &ddr3_regs,
 				&ddr3_data);
 	} else {
-- 
2.30.2


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Re: [PATCH master] Revert "ARM: beaglebone: init MPU speed to 800Mhz"

[Ahmad Fatoum]

Hello Marc,

On 03.12.21 19:51, Ahmad Fatoum wrote:
> Commit 130c7d6715e9 ("ARM: beaglebone: init MPU speed to 800Mhz") causes
> warm reboot from within Linux v5.14.0 to no longer succeed.
> barebox MLO is entered, but hangs. Reset from within barebox is
> unaffected.
> This can be reproduced using DistroKit 949c5ef2b9a6 ("v7a: barebox:
> version bump v2021.08.0 → v2021.11.0") on a Beaglebone Black.
> Until that's figured out, revert the commit; functional reboot is more
> important than the quicker boot up.
> 
> This reverts commit 130c7d6715e932a1e0b3e026fea97f700ab33ea9.

I send a revert, so barebox v2021.12.0 can ship with the regression fixed.
Would be great if you could take a look to see what needs to be done
differently to reinstate the clock frequency increase.

Cheers,
Ahmad

> 
> Fixes: 130c7d6715e9 ("ARM: beaglebone: init MPU speed to 800Mhz")
> Reported-by: arwie # IRC
> Cc: Marc Reilly <marc@cpdesign.com.au>
> Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
> ---
>  arch/arm/boards/beaglebone/lowlevel.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/arm/boards/beaglebone/lowlevel.c b/arch/arm/boards/beaglebone/lowlevel.c
> index 31211448f5e8..91d143e4150b 100644
> --- a/arch/arm/boards/beaglebone/lowlevel.c
> +++ b/arch/arm/boards/beaglebone/lowlevel.c
> @@ -126,7 +126,7 @@ static noinline int beaglebone_sram_init(void)
>  
>  	/* Setup the PLLs and the clocks for the peripherals */
>  	if (is_beaglebone_black()) {
> -		am33xx_pll_init(MPUPLL_M_800, DDRPLL_M_400);
> +		am33xx_pll_init(MPUPLL_M_500, DDRPLL_M_400);
>  		am335x_sdram_init(0x18B, &ddr3_cmd_ctrl, &ddr3_regs,
>  				&ddr3_data);
>  	} else {
> 


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Re: [PATCH master] Revert "ARM: beaglebone: init MPU speed to 800Mhz"

[Sascha Hauer]

On Fri, Dec 03, 2021 at 07:51:54PM +0100, Ahmad Fatoum wrote:
> Commit 130c7d6715e9 ("ARM: beaglebone: init MPU speed to 800Mhz") causes
> warm reboot from within Linux v5.14.0 to no longer succeed.
> barebox MLO is entered, but hangs. Reset from within barebox is
> unaffected.
> This can be reproduced using DistroKit 949c5ef2b9a6 ("v7a: barebox:
> version bump v2021.08.0 → v2021.11.0") on a Beaglebone Black.
> Until that's figured out, revert the commit; functional reboot is more
> important than the quicker boot up.
> 
> This reverts commit 130c7d6715e932a1e0b3e026fea97f700ab33ea9.
> 
> Fixes: 130c7d6715e9 ("ARM: beaglebone: init MPU speed to 800Mhz")
> Reported-by: arwie # IRC
> Cc: Marc Reilly <marc@cpdesign.com.au>
> Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
> ---
>  arch/arm/boards/beaglebone/lowlevel.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)

Applied, thanks

Sascha

> 
> diff --git a/arch/arm/boards/beaglebone/lowlevel.c b/arch/arm/boards/beaglebone/lowlevel.c
> index 31211448f5e8..91d143e4150b 100644
> --- a/arch/arm/boards/beaglebone/lowlevel.c
> +++ b/arch/arm/boards/beaglebone/lowlevel.c
> @@ -126,7 +126,7 @@ static noinline int beaglebone_sram_init(void)
>  
>  	/* Setup the PLLs and the clocks for the peripherals */
>  	if (is_beaglebone_black()) {
> -		am33xx_pll_init(MPUPLL_M_800, DDRPLL_M_400);
> +		am33xx_pll_init(MPUPLL_M_500, DDRPLL_M_400);
>  		am335x_sdram_init(0x18B, &ddr3_cmd_ctrl, &ddr3_regs,
>  				&ddr3_data);
>  	} else {
> -- 
> 2.30.2
> 
> 
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-- 
Pengutronix e.K.                           |                             |
Steuerwalder Str. 21                       | http://www.pengutronix.de/  |
31137 Hildesheim, Germany                  | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |

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