When disabled the PIT runs until it reaches the CPIV value. The Linux PIT driver stops the PIT and waits until it stopped. This can take over 100ms. Simply stopping in u-boot isn't sufficient as the PIT will still be running when Linux is waiting until it stopped. So, we stop it in u-boot by setting the compare value to a value slightly greater than the current running counter to make the PIT stopped in short time.
Signed-off-by: Alexander Stein alexander.stein@systec-electronic.com ---
Changes in v3: * Really fix comment
arch/arm/cpu/arm926ejs/at91/cpu.c | 16 ++++++++++++++++ 1 files changed, 16 insertions(+), 0 deletions(-)
diff --git a/arch/arm/cpu/arm926ejs/at91/cpu.c b/arch/arm/cpu/arm926ejs/at91/cpu.c index 141a7d1..110c361 100644 --- a/arch/arm/cpu/arm926ejs/at91/cpu.c +++ b/arch/arm/cpu/arm926ejs/at91/cpu.c @@ -28,6 +28,7 @@
#include <asm/arch/hardware.h> #include <asm/arch/at91_pmc.h> +#include <asm/arch/at91_pit.h> #include <asm/arch/clk.h> #include <asm/arch/io.h>
@@ -47,6 +48,21 @@ int arch_cpu_init(void) return at91_clock_init(CONFIG_SYS_AT91_MAIN_CLOCK); }
+void arch_preboot_os(void) +{ + ulong cpiv; + at91_pit_t *pit = (at91_pit_t *) AT91_PIT_BASE; + + cpiv = AT91_PIT_MR_PIV_MASK(readl(&pit->piir)); + + /* + * Disable PITC + * Add 0x1000 to current counter to stop it faster + * without waiting for wrapping back to 0 + */ + writel(cpiv + 0x1000, &pit->mr); +} + #if defined(CONFIG_DISPLAY_CPUINFO) int print_cpuinfo(void) {