ARM: atmel: switch to main crystal osc for SPL boot
If without switch to main crystal oscillator, the sama5d3 SoC will
use internal on chip RC oscillator.
In order to get better accuracy, switch to main crystal oscillator.
Signed-off-by: Bo Shen <voice.shen@atmel.com>
Signed-off-by: Andreas Bießmann <andreas.devel@googlemail.com>
diff --git a/arch/arm/cpu/at91-common/spl.c b/arch/arm/cpu/at91-common/spl.c
index 7f4debb..cbb5a52 100644
--- a/arch/arm/cpu/at91-common/spl.c
+++ b/arch/arm/cpu/at91-common/spl.c
@@ -20,6 +20,43 @@
writel(AT91_WDT_MR_WDDIS, &wdt->mr);
}
+static void switch_to_main_crystal_osc(void)
+{
+ struct at91_pmc *pmc = (struct at91_pmc *)ATMEL_BASE_PMC;
+ u32 tmp;
+
+ tmp = readl(&pmc->mor);
+ tmp &= ~AT91_PMC_MOR_OSCOUNT(0xff);
+ tmp &= ~AT91_PMC_MOR_KEY(0xff);
+ tmp |= AT91_PMC_MOR_MOSCEN;
+ tmp |= AT91_PMC_MOR_OSCOUNT(8);
+ tmp |= AT91_PMC_MOR_KEY(0x37);
+ writel(tmp, &pmc->mor);
+ while (!(readl(&pmc->sr) & AT91_PMC_IXR_MOSCS))
+ ;
+
+ tmp = readl(&pmc->mor);
+ tmp &= ~AT91_PMC_MOR_OSCBYPASS;
+ tmp &= ~AT91_PMC_MOR_KEY(0xff);
+ tmp |= AT91_PMC_MOR_KEY(0x37);
+ writel(tmp, &pmc->mor);
+
+ tmp = readl(&pmc->mor);
+ tmp |= AT91_PMC_MOR_MOSCSEL;
+ tmp &= ~AT91_PMC_MOR_KEY(0xff);
+ tmp |= AT91_PMC_MOR_KEY(0x37);
+ writel(tmp, &pmc->mor);
+
+ while (!(readl(&pmc->sr) & AT91_PMC_IXR_MOSCSELS))
+ ;
+
+ tmp = readl(&pmc->mor);
+ tmp &= ~AT91_PMC_MOR_MOSCRCEN;
+ tmp &= ~AT91_PMC_MOR_KEY(0xff);
+ tmp |= AT91_PMC_MOR_KEY(0x37);
+ writel(tmp, &pmc->mor);
+}
+
void at91_plla_init(u32 pllar)
{
struct at91_pmc *pmc = (struct at91_pmc *)ATMEL_BASE_PMC;
@@ -76,6 +113,8 @@
void s_init(void)
{
+ switch_to_main_crystal_osc();
+
/* disable watchdog */
at91_disable_wdt();
diff --git a/arch/arm/include/asm/arch-at91/at91_pmc.h b/arch/arm/include/asm/arch-at91/at91_pmc.h
index 4535608..04f6239 100644
--- a/arch/arm/include/asm/arch-at91/at91_pmc.h
+++ b/arch/arm/include/asm/arch-at91/at91_pmc.h
@@ -70,7 +70,10 @@
#define AT91_PMC_MOR_MOSCEN 0x01
#define AT91_PMC_MOR_OSCBYPASS 0x02
+#define AT91_PMC_MOR_MOSCRCEN 0x08
#define AT91_PMC_MOR_OSCOUNT(x) ((x & 0xff) << 8)
+#define AT91_PMC_MOR_KEY(x) ((x & 0xff) << 16)
+#define AT91_PMC_MOR_MOSCSEL (1 << 24)
#define AT91_PMC_PLLXR_DIV(x) (x & 0xFF)
#define AT91_PMC_PLLXR_PLLCOUNT(x) ((x & 0x3F) << 8)
@@ -142,6 +145,7 @@
#define AT91_PMC_IXR_PCKRDY1 0x00000200
#define AT91_PMC_IXR_PCKRDY2 0x00000400
#define AT91_PMC_IXR_PCKRDY3 0x00000800
+#define AT91_PMC_IXR_MOSCSELS 0x00010000
#define AT91_PMC_PCK (1 << 0) /* Processor Clock */
#define AT91RM9200_PMC_UDP (1 << 1) /* USB Devcice Port Clock [AT91RM9200 only] */