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 --- 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] */