[U-Boot] [PATCH 1/2] ARM: atmel: switch to main crystal osc for SPL boot

[Bo Shen]

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 at atmel.com>
---
 arch/arm/cpu/at91-common/spl.c            | 39 +++++++++++++++++++++++++++++++
 arch/arm/include/asm/arch-at91/at91_pmc.h |  4 ++++
 2 files changed, 43 insertions(+)

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 @@ static void at91_disable_wdt(void)
 	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 @@ u32 spl_boot_mode(void)
 
 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 @@ typedef struct at91_pmc {
 
 #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 @@ typedef struct at91_pmc {
 #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] */
-- 
1.8.5.2