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ARM: at91: pm: add support for ULP0 fast wakeup

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ULP0 fast improves suspend/resume time with few milliseconds the drawback
being the power consumption. The mean values measured for suspend/resume
time are as follows (measured on SAMA5D2 Xplained board), ULP0 compared
with fast ULP0:
- ulp0 fast: suspend time: 169 ms, resume time: 216 ms
- ulp0     : suspend time: 197 ms, resume time: 258 ms

Current consumption while suspended (measured on SAMA5D2 Xplained board):
- ulp0 fast: 730uA
- ulp0     : 270uA

Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/1596616610-15460-2-git-send-email-claudiu.beznea@microchip.com
This commit is contained in:
Claudiu Beznea 2020-08-05 11:36:48 +03:00 • committed by Alexandre Belloni
parent 9123e3a74e
commit e70bfc2fa8
3 changed files with 45 additions and 10 deletions
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9
arch/arm/mach-at91/pm.c
View file

@ -51,10 +51,11 @@ static struct at91_soc_pm soc_pm = {
};
static const match_table_t pm_modes __initconst = {
{ AT91_PM_STANDBY, "standby" },
{ AT91_PM_ULP0, "ulp0" },
{ AT91_PM_ULP1, "ulp1" },
{ AT91_PM_BACKUP, "backup" },
{ AT91_PM_STANDBY, "standby" },
{ AT91_PM_ULP0, "ulp0" },
{ AT91_PM_ULP0_FAST, "ulp0-fast" },
{ AT91_PM_ULP1, "ulp1" },
{ AT91_PM_BACKUP, "backup" },
{ -1, NULL },
};

5
arch/arm/mach-at91/pm.h
View file

@ -19,8 +19,9 @@
#define AT91_PM_STANDBY 0x00
#define AT91_PM_ULP0 0x01
#define AT91_PM_ULP1 0x02
#define AT91_PM_BACKUP 0x03
#define AT91_PM_ULP0_FAST 0x02
#define AT91_PM_ULP1 0x03
#define AT91_PM_BACKUP 0x04
#ifndef __ASSEMBLY__
struct at91_pm_data {

41
arch/arm/mach-at91/pm_suspend.S
View file

@ -164,7 +164,22 @@ ENDPROC(at91_backup_mode)
.macro at91_pm_ulp0_mode
ldr pmc, .pmc_base
ldr tmp2, .pm_mode
ldr tmp3, .mckr_offset
/* Check if ULP0 fast variant has been requested. */
cmp tmp2, #AT91_PM_ULP0_FAST
bne 0f
/* Set highest prescaler for power saving */
ldr tmp1, [pmc, tmp3]
bic tmp1, tmp1, #AT91_PMC_PRES
orr tmp1, tmp1, #AT91_PMC_PRES_64
str tmp1, [pmc, tmp3]
wait_mckrdy
b 1f
0:
/* Turn off the crystal oscillator */
ldr tmp1, [pmc, #AT91_CKGR_MOR]
bic tmp1, tmp1, #AT91_PMC_MOSCEN
@ -192,7 +207,18 @@ ENDPROC(at91_backup_mode)
/* Wait for interrupt */
1: at91_cpu_idle
/* Restore RC oscillator state */
/* Check if ULP0 fast variant has been requested. */
cmp tmp2, #AT91_PM_ULP0_FAST
bne 5f
/* Set lowest prescaler for fast resume. */
ldr tmp1, [pmc, tmp3]
bic tmp1, tmp1, #AT91_PMC_PRES
str tmp1, [pmc, tmp3]
wait_mckrdy
b 6f
5: /* Restore RC oscillator state */
ldr tmp1, .saved_osc_status
tst tmp1, #AT91_PMC_MOSCRCS
beq 4f
@ -216,6 +242,7 @@ ENDPROC(at91_backup_mode)
str tmp1, [pmc, #AT91_CKGR_MOR]
wait_moscrdy
6:
.endm
/**
@ -473,23 +500,29 @@ ENDPROC(at91_backup_mode)
ENTRY(at91_ulp_mode)
ldr pmc, .pmc_base
ldr tmp2, .mckr_offset
ldr tmp3, .pm_mode
/* Save Master clock setting */
ldr tmp1, [pmc, tmp2]
str tmp1, .saved_mckr
/*
* Set the Master clock source to slow clock
* Set master clock source to:
* - MAINCK if using ULP0 fast variant
* - slow clock, otherwise
*/
bic tmp1, tmp1, #AT91_PMC_CSS
cmp tmp3, #AT91_PM_ULP0_FAST
bne save_mck
orr tmp1, tmp1, #AT91_PMC_CSS_MAIN
save_mck:
str tmp1, [pmc, tmp2]
wait_mckrdy
at91_plla_disable
ldr r0, .pm_mode
cmp r0, #AT91_PM_ULP1
cmp tmp3, #AT91_PM_ULP1
beq ulp1_mode
at91_pm_ulp0_mode