Commit e70bfc2f authored by Claudiu Beznea's avatar Claudiu Beznea Committed by Alexandre Belloni
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ARM: at91: pm: add support for ULP0 fast wakeup 



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: default avatarClaudiu Beznea <claudiu.beznea@microchip.com>
Signed-off-by: default avatarAlexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/1596616610-15460-2-git-send-email-claudiu.beznea@microchip.com
parent 9123e3a7

arch/arm/mach-at91/pm.c

+5 −4
Original line number Diff line number Diff line
@@ -53,6 +53,7 @@ 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_ULP0_FAST,    "ulp0-fast" },

	{ AT91_PM_ULP1,		"ulp1" },

	{ AT91_PM_BACKUP,	"backup" },

	{ -1, NULL },

arch/arm/mach-at91/pm.h

+3 −2
Original line number Diff line number Diff line
@@ -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 {

arch/arm/mach-at91/pm_suspend.S

+37 −4
Original line number Diff line number Diff line
@@ -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

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