ARM: at91: pm: disable RC oscillator in ULP0

Disable RC oscillator in ULP0 as datasheet specifies.

Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Ludovic Desroches <ludovic.desroches@microchip.com>

1 files changed, 37 insertions, 2 deletions

diff --git a/arch/arm/mach-at91/pm_suspend.S b/arch/arm/mach-at91/pm_suspend.S
index 8b18cad1dcf5..5c33023f9129 100644
--- a/arch/arm/mach-at91/pm_suspend.S
+++ b/arch/arm/mach-at91/pm_suspend.S
@@ -178,11 +178,46 @@ ENDPROC(at91_backup_mode)
         orr     tmp1, tmp1, #AT91_PMC_KEY
         str     tmp1, [pmc, #AT91_CKGR_MOR]
 
+        /* Save RC oscillator state */
+        ldr     tmp1, [pmc, #AT91_PMC_SR]
+        str     tmp1, .saved_osc_status
+        tst     tmp1, #AT91_PMC_MOSCRCS
+        bne     1f
+
+        /* Turn off RC oscillator */
+        ldr     tmp1, [pmc, #AT91_CKGR_MOR]
+        bic     tmp1, tmp1, #AT91_PMC_MOSCRCEN
+        bic     tmp1, tmp1, #AT91_PMC_KEY_MASK
+        orr     tmp1, tmp1, #AT91_PMC_KEY
+        str     tmp1, [pmc, #AT91_CKGR_MOR]
+
+        /* Wait main RC disabled done */
+2:      ldr     tmp1, [pmc, #AT91_PMC_SR]
+        tst     tmp1, #AT91_PMC_MOSCRCS
+        bne     2b
+
         /* Wait for interrupt */
-        at91_cpu_idle
+1:      at91_cpu_idle
 
-        /* Turn on the crystal oscillator */
+        /* Restore RC oscillator state */
+        ldr     tmp1, .saved_osc_status
+        tst     tmp1, #AT91_PMC_MOSCRCS
+        beq     4f
+
+        /* Turn on RC oscillator */
         ldr     tmp1, [pmc, #AT91_CKGR_MOR]
+        orr     tmp1, tmp1, #AT91_PMC_MOSCRCEN
+        bic     tmp1, tmp1, #AT91_PMC_KEY_MASK
+        orr     tmp1, tmp1, #AT91_PMC_KEY
+        str     tmp1, [pmc, #AT91_CKGR_MOR]
+
+        /* Wait main RC stabilization */
+3:      ldr     tmp1, [pmc, #AT91_PMC_SR]
+        tst     tmp1, #AT91_PMC_MOSCRCS
+        beq     3b
+
+        /* Turn on the crystal oscillator */
+4:      ldr     tmp1, [pmc, #AT91_CKGR_MOR]
         orr     tmp1, tmp1, #AT91_PMC_MOSCEN
         orr     tmp1, tmp1, #AT91_PMC_KEY
         str     tmp1, [pmc, #AT91_CKGR_MOR]