ARM: tegra: don't exceed AVP limits when configuring PLLP

Based on the Tegra TRM, the system clock (which is the AVP clock) can
run up to 275MHz. On power on, the default sytem clock source is set to
PLLP_OUT0. In function clock_early_init(), PLLP_OUT0 will be set to
408MHz which is beyond system clock's upper limit.

The fix is to set the system clock to CLK_M before initializing PLLP,
and then switch back to PLLP_OUT4, which has an appropriate divider
configured, after PLLP has been configured

Implement this logic in new function tegra30_set_up_pllp(),
which sets up PLLP and all PLLP_OUT* dividers, and handles the AVP
clock switching. Remove the duplicate PLLP setup from pllx_set_rate()
and adjust_pllp_out_freqs().

Signed-off-by: Jimmy Zhang <jimmzhang@nvidia.com>
[swarren, significantly refactored the change]
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Reviewed-by: Thierry Reding <treding@nvidia.com>
Tested-by: Thierry Reding <treding@nvidia.com>
Acked-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Tom Warren <twarren@nvidia.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/arch/arm/include/asm/arch-tegra/clock.h b/arch/arm/include/asm/arch-tegra/clock.h
index 2f85696a58..9d8114c4ec 100644
--- a/arch/arm/include/asm/arch-tegra/clock.h
+++ b/arch/arm/include/asm/arch-tegra/clock.h
@@ -320,4 +320,6 @@ int clock_set_rate(enum clock_id clkid, u32 n, u32 m, u32 p, u32 cpcon);
 /* SoC-specific TSC init */
 void arch_timer_init(void);
 
+void tegra30_set_up_pllp(void);
+
 #endif  /* _TEGRA_CLOCK_H_ */