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ARM: atmel: switch to main crystal osc for SPL boot

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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>
This commit is contained in:
Bo Shen 2014-03-19 14:48:44 +08:00 committed by Andreas Bießmann
parent 49692c5f51
commit 12bbc0ba81
2 changed files with 43 additions and 0 deletions
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39
arch/arm/cpu/at91-common/spl.c
View file

@ -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();

4
arch/arm/include/asm/arch-at91/at91_pmc.h
View file

@ -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] */