Hi Heiko,
-----Original Message----- From: U-Boot [mailto:u-boot-bounces@lists.denx.de] On Behalf Of Heiko Schocher Sent: 2016年8月17日 15:13 To: U-Boot Mailing List u-boot@lists.denx.de Cc: Bo Shen voice.shen@atmel.com Subject: [U-Boot] [PATCH 6/6] [RFC] at91: SPL clock fix for AT91SAM9G15 based boards.
on a at91sam9g15 basd board I need another MOR register init as common for at91 based boards. Changes: MM
- set AT91_PMC_MOR_KEY to 0x37, without this writting has no effect to tthis register.
- AT91_PMC_MOR_OSCOUNT to 0
- set AT91_PMC_MOR_MOSCEN and AT91_PMC_MOR_MOSCSEL
Signed-off-by: Heiko Schocher hs@denx.de
I post this as a RFC patch, because this settings may break other boards ... so if this is not a valid common setting, I propose to make this setting board configurable through a weak function ...
arch/arm/mach-at91/spl_at91.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-)
diff --git a/arch/arm/mach-at91/spl_at91.c b/arch/arm/mach-at91/spl_at91.c index cc3341a..4d8ed26 100644 --- a/arch/arm/mach-at91/spl_at91.c +++ b/arch/arm/mach-at91/spl_at91.c @@ -31,13 +31,20 @@ static void enable_ext_reset(void) void lowlevel_clock_init(void) { struct at91_pmc *pmc = (struct at91_pmc *)ATMEL_BASE_PMC;
u32 tmp;
if (!(readl(&pmc->sr) & AT91_PMC_MOSCS)) {
/* Enable Main Oscillator */writel(AT91_PMC_MOSCS | (0x40 << 8), &pmc->mor);
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_MOSCSEL;tmp |= AT91_PMC_MOR_OSCOUNT(0);tmp |= AT91_PMC_MOR_KEY(0x37);writel(tmp, &pmc->mor);
I think, it needs two steps to configure the CKGR_MOR register. 1./ set AT91_PMC_MOR_MOSCEN, then wait to check the MOSCXTS bit of the PMC Status Register. 2./ set AT91_PMC_MOR_MOSCSEL, then wait for check the MOSCSLES bit of the PMC Status Register.
AT91_PMC_MOR_OSCOUNT should not be set 0.
/* Wait until Main Oscillator is stable */
while (!(readl(&pmc->sr) & AT91_PMC_MOSCS))
while (!(readl(&pmc->sr) & AT91_PMC_IXR_MOSCS)) ;-- 2.5.5
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Best Regards, Wenyou Yang