+void at91_system_clk_enable(int sys_clk);
+void at91_system_clk_disable(int sys_clk);
+int at91_upll_clk_enable(void);
+int at91_upll_clk_disable(void);
+void at91_usb_clk_init(u32 value);
+int at91_pllb_clk_enable(u32 pllbr);
+int at91_pllb_clk_disable(void);
+void at91_pllicpr_init(u32 icpr);