clock_control_bflb_common.h

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/*
 * Copyright (c) 2025 MASSDRIVER EI (massdriver.space)
 *
 * SPDX-License-Identifier: Apache-2.0
 */

 
#ifndef ZEPHYR_INCLUDE_DRIVERS_CLOCK_CONTROL_CLOCK_CONTROL_BFLB_COMMON_H_
#define ZEPHYR_INCLUDE_DRIVERS_CLOCK_CONTROL_CLOCK_CONTROL_BFLB_COMMON_H_


#define BFLB_MAIN_CLOCK_RC32M     0
#define BFLB_MAIN_CLOCK_XTAL      1
#define BFLB_MAIN_CLOCK_PLL_RC32M 2
#define BFLB_MAIN_CLOCK_PLL_XTAL  3

static inline void clock_bflb_settle(void)
{
        __asm__ volatile (".rept 20 ; nop ; .endr");
}

static inline void clock_bflb_set_root_clock(uint32_t clock)
{
        uint32_t tmp;
 
        /* invalid value, fallback to internal 32M */
        if (clock > BFLB_MAIN_CLOCK_PLL_XTAL) {
                clock = BFLB_MAIN_CLOCK_RC32M;
        }
        tmp = sys_read32(HBN_BASE + HBN_GLB_OFFSET);
        tmp = (tmp & HBN_ROOT_CLK_SEL_UMSK) | (clock << HBN_ROOT_CLK_SEL_POS);
        sys_write32(tmp, HBN_BASE + HBN_GLB_OFFSET);
 
        clock_bflb_settle();
}

static inline uint32_t clock_bflb_get_root_clock(void)
{
        uint32_t tmp;
 
        tmp = sys_read32(HBN_BASE + HBN_GLB_OFFSET);
        return ((tmp & HBN_ROOT_CLK_SEL_MSK) >> HBN_ROOT_CLK_SEL_POS);
}
 

 
/* Avoid overflow when calculating multipliers by reducing precision to 100 KHz
 * Every _value and _base should be a multiple of this to stay exact
 */
#define BFLB_MUL_CLK_UNIT       100000U
 
/* (_value * _top) / _base without 64-bit division. _top is evaluated twice. */
#define BFLB_MUL_CLK(_value, _top, _base) \
        ((((uint32_t)(_top) / ((uint32_t)(_base) / BFLB_MUL_CLK_UNIT)) * \
          ((uint32_t)(_value) / BFLB_MUL_CLK_UNIT)) + \
         ((((uint32_t)(_top) % ((uint32_t)(_base) / BFLB_MUL_CLK_UNIT)) * \
           ((uint32_t)(_value) / BFLB_MUL_CLK_UNIT)) / \
          ((uint32_t)(_base) / BFLB_MUL_CLK_UNIT)))
 
/* Runnable from XIP (__udivdi3 call from libgcc) */
#define BFLB_MUL_CLK_XIP(_value, _top, _base) \
        (((uint64_t)(_value) * (uint64_t)(_top)) / (uint64_t)(_base))


 
#endif /* ZEPHYR_INCLUDE_DRIVERS_CLOCK_CONTROL_CLOCK_CONTROL_BFLB_COMMON_H_ */