[PATCH v5 2/5] ARM: at91: pm: add ULP1 mode support

From: Wenyou Yang
Date: Wed Mar 16 2016 - 03:04:43 EST

The ULP1 (Ultra Low-power mode 1) is introduced by SAMA5D2.

In the ULP1 mode, all the clocks are shut off, inclusive the embedded
12MHz RC oscillator, so as to achieve the lowest power consumption
with the system in retention mode and able to resume on the wake up
events. As soon as the wake up event is asserted, the embedded 12MHz
RC oscillator restarts automatically.

Signed-off-by: Wenyou Yang <wenyou.yang@xxxxxxxxx>
---

Changes in v5: None
Changes in v4: None
Changes in v3: None
Changes in v2:
- fix label pm_exit to ulp_exit.

arch/arm/mach-at91/pm.c | 16 ++++++-
arch/arm/mach-at91/pm.h | 7 +++
arch/arm/mach-at91/pm_suspend.S | 97 +++++++++++++++++++++++++++++++++++++++
include/linux/clk/at91_pmc.h | 4 ++
4 files changed, 122 insertions(+), 2 deletions(-)

diff --git a/arch/arm/mach-at91/pm.c b/arch/arm/mach-at91/pm.c
index f062701..5c2db34 100644
--- a/arch/arm/mach-at91/pm.c
+++ b/arch/arm/mach-at91/pm.c
@@ -36,6 +36,11 @@
#include "generic.h"
#include "pm.h"

+#define ULP0_MODE 0x00
+#define ULP1_MODE 0x11
+
+#define SAMA5D2_PMC_VERSION 0x20540
+
static void __iomem *pmc;

/*
@@ -52,6 +57,7 @@ extern void at91_pinctrl_gpio_resume(void);
static struct {
unsigned long uhp_udp_mask;
int memctrl;
+ u32 ulp_mode;
} at91_pm_data;

void __iomem *at91_ramc_base[2];
@@ -141,8 +147,11 @@ static void at91_pm_suspend(suspend_state_t state)
{
unsigned int pm_data = at91_pm_data.memctrl;

- pm_data |= (state == PM_SUSPEND_MEM) ?
- AT91_PM_MODE(AT91_PM_SLOW_CLOCK) : 0;
+ if (state == PM_SUSPEND_MEM) {
+ pm_data |= AT91_PM_MODE(AT91_PM_SLOW_CLOCK);
+ if (at91_pm_data.ulp_mode == ULP1_MODE)
+ pm_data |= AT91_PM_ULP(AT91_PM_ULP1_MODE);
+ }

flush_cache_all();
outer_disable();
@@ -497,4 +506,7 @@ void __init sama5_pm_init(void)
at91_pm_data.uhp_udp_mask = AT91SAM926x_PMC_UHP | AT91SAM926x_PMC_UDP;
at91_pm_data.memctrl = AT91_MEMCTRL_DDRSDR;
at91_pm_init(NULL);
+
+ if (readl(pmc + AT91_PMC_VERSION) >= SAMA5D2_PMC_VERSION)
+ at91_pm_data.ulp_mode = ULP1_MODE;
}
diff --git a/arch/arm/mach-at91/pm.h b/arch/arm/mach-at91/pm.h
index 3fcf881..2e76745 100644
--- a/arch/arm/mach-at91/pm.h
+++ b/arch/arm/mach-at91/pm.h
@@ -39,4 +39,11 @@ extern void __iomem *at91_ramc_base[];

#define AT91_PM_SLOW_CLOCK 0x01

+#define AT91_PM_ULP_OFFSET 5
+#define AT91_PM_ULP_MASK 0x03
+#define AT91_PM_ULP(x) (((x) & AT91_PM_ULP_MASK) << AT91_PM_ULP_OFFSET)
+
+#define AT91_PM_ULP0_MODE 0x00
+#define AT91_PM_ULP1_MODE 0x01
+
#endif
diff --git a/arch/arm/mach-at91/pm_suspend.S b/arch/arm/mach-at91/pm_suspend.S
index 5fcffdc..f2a5c4b 100644
--- a/arch/arm/mach-at91/pm_suspend.S
+++ b/arch/arm/mach-at91/pm_suspend.S
@@ -41,6 +41,15 @@ tmp2 .req r5
.endm

/*
+ * Wait for main oscillator selection is done
+ */
+ .macro wait_moscsels
+1: ldr tmp1, [pmc, #AT91_PMC_SR]
+ tst tmp1, #AT91_PMC_MOSCSELS
+ beq 1b
+ .endm
+
+/*
* Wait until PLLA has locked.
*/
.macro wait_pllalock
@@ -101,6 +110,10 @@ ENTRY(at91_pm_suspend_in_sram)
and r0, r0, #AT91_PM_MODE_MASK
str r0, .pm_mode

+ lsr r0, r3, #AT91_PM_ULP_OFFSET
+ and r0, r0, #AT91_PM_ULP_MASK
+ str r0, .ulp_mode
+
/* Active the self-refresh mode */
mov r0, #SRAMC_SELF_FRESH_ACTIVE
bl at91_sramc_self_refresh
@@ -131,6 +144,13 @@ ENTRY(at91_pm_suspend_in_sram)
orr tmp1, tmp1, #(1 << 29) /* bit 29 always set */
str tmp1, [pmc, #AT91_CKGR_PLLAR]

+ ldr r0, .ulp_mode
+ tst r0, #AT91_PM_ULP1_MODE
+ beq ulp0_mode
+
+ bl at91_pm_ulp1_mode
+ b ulp_exit
+
ulp0_mode:
bl at91_pm_ulp0_mode
b ulp_exit
@@ -326,6 +346,81 @@ ENTRY(at91_pm_ulp0_mode)
mov pc, lr
ENDPROC(at91_pm_ulp0_mode)

+/*
+ * void at91_pm_ulp1_mode(void)
+ */
+ENTRY(at91_pm_ulp1_mode)
+ ldr pmc, .pmc_base
+
+ /* Switch the main clock source to 12-MHz RC oscillator */
+ ldr tmp1, [pmc, #AT91_CKGR_MOR]
+ bic tmp1, tmp1, #AT91_PMC_MOSCSEL
+ bic tmp1, tmp1, #AT91_PMC_KEY_MASK
+ orr tmp1, tmp1, #AT91_PMC_KEY
+ str tmp1, [pmc, #AT91_CKGR_MOR]
+
+ wait_moscsels
+
+ /* Disable the crystal oscillator */
+ ldr tmp1, [pmc, #AT91_CKGR_MOR]
+ bic tmp1, tmp1, #AT91_PMC_MOSCEN
+ bic tmp1, tmp1, #AT91_PMC_KEY_MASK
+ orr tmp1, tmp1, #AT91_PMC_KEY
+ str tmp1, [pmc, #AT91_CKGR_MOR]
+
+ /* Switch the master clock source to main clock */
+ ldr tmp1, [pmc, #AT91_PMC_MCKR]
+ bic tmp1, tmp1, #AT91_PMC_CSS
+ orr tmp1, tmp1, #AT91_PMC_CSS_MAIN
+ str tmp1, [pmc, #AT91_PMC_MCKR]
+
+ wait_mckrdy
+
+ /* Enter the ULP1 mode by set WAITMODE bit in CKGR_MOR */
+ ldr tmp1, [pmc, #AT91_CKGR_MOR]
+ orr tmp1, tmp1, #AT91_PMC_WAITMODE
+ bic tmp1, tmp1, #AT91_PMC_KEY_MASK
+ orr tmp1, tmp1, #AT91_PMC_KEY
+ str tmp1, [pmc, #AT91_CKGR_MOR]
+
+ wait_mckrdy
+
+ /* Enable the crystal oscillator */
+ ldr tmp1, [pmc, #AT91_CKGR_MOR]
+ orr tmp1, tmp1, #AT91_PMC_MOSCEN
+ bic tmp1, tmp1, #AT91_PMC_KEY_MASK
+ orr tmp1, tmp1, #AT91_PMC_KEY
+ str tmp1, [pmc, #AT91_CKGR_MOR]
+
+ wait_moscrdy
+
+ /* Switch the master clock source to slow clock */
+ ldr tmp1, [pmc, #AT91_PMC_MCKR]
+ bic tmp1, tmp1, #AT91_PMC_CSS
+ str tmp1, [pmc, #AT91_PMC_MCKR]
+
+ wait_mckrdy
+
+ /* Switch main clock source to crystal oscillator */
+ ldr tmp1, [pmc, #AT91_CKGR_MOR]
+ orr tmp1, tmp1, #AT91_PMC_MOSCSEL
+ bic tmp1, tmp1, #AT91_PMC_KEY_MASK
+ orr tmp1, tmp1, #AT91_PMC_KEY
+ str tmp1, [pmc, #AT91_CKGR_MOR]
+
+ wait_moscsels
+
+ /* Switch the master clock source to main clock */
+ ldr tmp1, [pmc, #AT91_PMC_MCKR]
+ bic tmp1, tmp1, #AT91_PMC_CSS
+ orr tmp1, tmp1, #AT91_PMC_CSS_MAIN
+ str tmp1, [pmc, #AT91_PMC_MCKR]
+
+ wait_mckrdy
+
+ mov pc, lr
+ENDPROC(at91_pm_ulp1_mode)
+
.pmc_base:
.word 0
.sramc_base:
@@ -336,6 +431,8 @@ ENDPROC(at91_pm_ulp0_mode)
.word 0
.pm_mode:
.word 0
+.ulp_mode:
+ .word 0
.saved_mckr:
.word 0
.saved_pllar:
diff --git a/include/linux/clk/at91_pmc.h b/include/linux/clk/at91_pmc.h
index 17f413b..4afd891 100644
--- a/include/linux/clk/at91_pmc.h
+++ b/include/linux/clk/at91_pmc.h
@@ -47,8 +47,10 @@
#define AT91_CKGR_MOR 0x20 /* Main Oscillator Register [not on SAM9RL] */
#define AT91_PMC_MOSCEN (1 << 0) /* Main Oscillator Enable */
#define AT91_PMC_OSCBYPASS (1 << 1) /* Oscillator Bypass */
+#define AT91_PMC_WAITMODE (1 << 2) /* Wait Mode Command */
#define AT91_PMC_MOSCRCEN (1 << 3) /* Main On-Chip RC Oscillator Enable [some SAM9] */
#define AT91_PMC_OSCOUNT (0xff << 8) /* Main Oscillator Start-up Time */
+#define AT91_PMC_KEY_MASK (0xff << 16)
#define AT91_PMC_KEY (0x37 << 16) /* MOR Writing Key */
#define AT91_PMC_MOSCSEL (1 << 24) /* Main Oscillator Selection [some SAM9] */
#define AT91_PMC_CFDEN (1 << 25) /* Clock Failure Detector Enable [some SAM9] */
@@ -166,6 +168,8 @@
#define AT91_PMC_WPVS (0x1 << 0) /* Write Protect Violation Status */
#define AT91_PMC_WPVSRC (0xffff << 8) /* Write Protect Violation Source */

+#define AT91_PMC_VERSION 0xfc
+
#define AT91_PMC_PCER1 0x100 /* Peripheral Clock Enable Register 1 [SAMA5 only]*/
#define AT91_PMC_PCDR1 0x104 /* Peripheral Clock Enable Register 1 */
#define AT91_PMC_PCSR1 0x108 /* Peripheral Clock Enable Register 1 */
--
1.7.9.5