[PATCH 0/3] ARM: at91: enhance PM routines

[PATCH 0/3] ARM: at91: enhance PM routines

[nicolas.ferre]

From: Nicolas Ferre <nicolas.ferre@microchip.com>

Low priority fixes to the PM code, in relation to recent addition of sam9x75 or
sama7d65 SoCs.

Nicolas Ferre (3):
  ARM: at91: pm: fix .uhp_udp_mask specification for current SoCs
  ARM: at91: pm: fix MCKx restore routine
  ARM: at91: pm: save and restore ACR during PLL disable/enable

 arch/arm/mach-at91/pm.c         |  2 +-
 arch/arm/mach-at91/pm_suspend.S | 12 +++++++++---
 2 files changed, 10 insertions(+), 4 deletions(-)

-- 
2.43.0

[PATCH 1/3] ARM: at91: pm: fix .uhp_udp_mask specification for current SoCs

[nicolas.ferre]

From: Nicolas Ferre <nicolas.ferre@microchip.com>

All SoCs using this structure field .uhp_udp_mask in configuration
index 4 don't have the bit 7 specified: sam9x60 nor sam9x75.
Remove this bit from the mask definition to match register layout.

This mask is used in function at91_pm_verify_clocks().

Signed-off-by: Nicolas Ferre <nicolas.ferre@microchip.com>
---
 arch/arm/mach-at91/pm.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm/mach-at91/pm.c b/arch/arm/mach-at91/pm.c
index 3aa20038ad93..35058b99069c 100644
--- a/arch/arm/mach-at91/pm.c
+++ b/arch/arm/mach-at91/pm.c
@@ -1364,7 +1364,7 @@ static const struct pmc_info pmc_infos[] __initconst = {
 		.version = AT91_PMC_V1,
 	},
 	{
-		.uhp_udp_mask = AT91SAM926x_PMC_UHP | AT91SAM926x_PMC_UDP,
+		.uhp_udp_mask = AT91SAM926x_PMC_UHP,
 		.mckr = 0x28,
 		.version = AT91_PMC_V2,
 	},
-- 
2.43.0

[PATCH 2/3] ARM: at91: pm: fix MCKx restore routine

[nicolas.ferre]

From: Nicolas Ferre <nicolas.ferre@microchip.com>

The at91_mckx_ps_restore() assembly function is responsible for setting
back MCKx system bus clocks after exiting low power modes.

Fix a typo and use tmp3 variable instead of tmp2 to correctly set MCKx
to previously saved sate.
Tmp2 was used without the needed changes in CSS and DIV. Moreover the
required bit 7, telling that MCR register's content is to be changed
(CMD/write), was not set.

Fix function comment to match tmp variables actually used.

Signed-off-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Fixes: 28eb1d40fe57 ("ARM: at91: pm: add support for MCK1..4 save/restore for ulp modes")
---
 arch/arm/mach-at91/pm_suspend.S | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/arm/mach-at91/pm_suspend.S b/arch/arm/mach-at91/pm_suspend.S
index e23b86834096..7e6c94f8edee 100644
--- a/arch/arm/mach-at91/pm_suspend.S
+++ b/arch/arm/mach-at91/pm_suspend.S
@@ -904,7 +904,7 @@ e_done:
 /**
  * at91_mckx_ps_restore: restore MCKx settings
  *
- * Side effects: overwrites tmp1, tmp2
+ * Side effects: overwrites tmp1, tmp2 and tmp3
  */
 .macro at91_mckx_ps_restore
 #ifdef CONFIG_SOC_SAMA7
@@ -980,7 +980,7 @@ r_ps:
 	bic	tmp3, tmp3, #AT91_PMC_MCR_V2_ID_MSK
 	orr	tmp3, tmp3, tmp1
 	orr	tmp3, tmp3, #AT91_PMC_MCR_V2_CMD
-	str	tmp2, [pmc, #AT91_PMC_MCR_V2]
+	str	tmp3, [pmc, #AT91_PMC_MCR_V2]
 
 	wait_mckrdy tmp1
 
-- 
2.43.0

[PATCH 3/3] ARM: at91: pm: save and restore ACR during PLL disable/enable

[nicolas.ferre]

From: Nicolas Ferre <nicolas.ferre@microchip.com>

Add a new word in assembly to store ACR value during the calls
to at91_plla_disable/at91_plla_enable macros and use it.

Signed-off-by: Nicolas Ferre <nicolas.ferre@microchip.com>
[cristian.birsan@microchip.com: remove ACR_DEFAULT_PLLA loading]
Signed-off-by: Cristian Birsan <cristian.birsan@microchip.com>
---
 arch/arm/mach-at91/pm_suspend.S | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/arch/arm/mach-at91/pm_suspend.S b/arch/arm/mach-at91/pm_suspend.S
index 7e6c94f8edee..aad53ec9e957 100644
--- a/arch/arm/mach-at91/pm_suspend.S
+++ b/arch/arm/mach-at91/pm_suspend.S
@@ -689,6 +689,10 @@ sr_dis_exit:
 	bic	tmp2, tmp2, #AT91_PMC_PLL_UPDT_ID
 	str	tmp2, [pmc, #AT91_PMC_PLL_UPDT]
 
+	/* save acr */
+	ldr	tmp2, [pmc, #AT91_PMC_PLL_ACR]
+	str	tmp2, .saved_acr
+
 	/* save div. */
 	mov	tmp1, #0
 	ldr	tmp2, [pmc, #AT91_PMC_PLL_CTRL0]
@@ -758,7 +762,7 @@ sr_dis_exit:
 	str	tmp1, [pmc, #AT91_PMC_PLL_UPDT]
 
 	/* step 2. */
-	ldr	tmp1, =AT91_PMC_PLL_ACR_DEFAULT_PLLA
+	ldr	tmp1, .saved_acr
 	str	tmp1, [pmc, #AT91_PMC_PLL_ACR]
 
 	/* step 3. */
@@ -1207,6 +1211,8 @@ ENDPROC(at91_pm_suspend_in_sram)
 #endif
 .saved_mckr:
 	.word 0
+.saved_acr:
+	.word 0
 .saved_pllar:
 	.word 0
 .saved_sam9_lpr:
-- 
2.43.0

Re: [PATCH 0/3] ARM: at91: enhance PM routines

[Alexandre Belloni]

On 27/08/2025 16:54:24+0200, Nicolas Ferre wrote:
> From: Nicolas Ferre <nicolas.ferre@microchip.com>
> 
> Low priority fixes to the PM code, in relation to recent addition of sam9x75 or
> sama7d65 SoCs.

Reviewed-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

> 
> Nicolas Ferre (3):
>   ARM: at91: pm: fix .uhp_udp_mask specification for current SoCs
>   ARM: at91: pm: fix MCKx restore routine
>   ARM: at91: pm: save and restore ACR during PLL disable/enable
> 
>  arch/arm/mach-at91/pm.c         |  2 +-
>  arch/arm/mach-at91/pm_suspend.S | 12 +++++++++---
>  2 files changed, 10 insertions(+), 4 deletions(-)
> 
> -- 
> 2.43.0
> 

-- 
Alexandre Belloni, co-owner and COO, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com