57 lines
1.5 KiB
C
57 lines
1.5 KiB
C
/*
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* Copyright (c) 2014 Travis Geiselbrecht
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*
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* Use of this source code is governed by a MIT-style
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* license that can be found in the LICENSE file or at
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* https://opensource.org/licenses/MIT
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*/
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#include <lk/err.h>
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#include <stdio.h>
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#include <lk/debug.h>
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#include <platform.h>
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#include <platform/lpc.h>
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#include <arch/arm/cm.h>
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void lpc_debug_early_init(void);
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void lpc_debug_init(void);
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void lpc_gpio_early_init(void);
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void lpc_gpio_init(void);
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void lpc_usbc_early_init(void);
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void lpc_usbc_init(void);
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void platform_early_init(void) {
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/* set up clocking for a board with an external oscillator */
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Chip_SetupXtalClocking();
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/* Set USB PLL input to main oscillator */
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Chip_Clock_SetUSBPLLSource(SYSCTL_PLLCLKSRC_MAINOSC);
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/* Setup USB PLL (FCLKIN = 12MHz) * 4 = 48MHz
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MSEL = 3 (this is pre-decremented), PSEL = 1 (for P = 2)
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FCLKOUT = FCLKIN * (MSEL + 1) = 12MHz * 4 = 48MHz
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FCCO = FCLKOUT * 2 * P = 48MHz * 2 * 2 = 192MHz (within FCCO range) */
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Chip_Clock_SetupUSBPLL(3, 1);
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/* Powerup USB PLL */
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Chip_SYSCTL_PowerUp(SYSCTL_POWERDOWN_USBPLL_PD);
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/* Wait for PLL to lock */
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while (!Chip_Clock_IsUSBPLLLocked()) {}
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/* Set default system tick divder to 1 */
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Chip_Clock_SetSysTickClockDiv(1);
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/* start the generic systick driver */
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arm_cm_systick_init(Chip_Clock_GetMainClockRate());
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lpc_debug_early_init();
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}
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void platform_init(void) {
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lpc_debug_init();
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}
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// vim: set ts=4 sw=4 expandtab:
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