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/*
* Copyright (c) 2020 Gerson Fernando Budke <nandojve@gmail.com>
* SPDX-License-Identifier: Apache-2.0
*/
/**
* @file
* @brief Atmel SAM4L MCU series initialization code
*
* This module provides routines to initialize and support board-level hardware
* for the Atmel SAM4L series processor.
*/
#include <device.h>
#include <init.h>
#include <soc.h>
#include <arch/cpu.h>
/** Watchdog control register first write keys */
#define WDT_FIRST_KEY 0x55ul
/** Watchdog control register second write keys */
#define WDT_SECOND_KEY 0xAAul
/**
* @brief Calculate \f$ \left\lceil \frac{a}{b} \right\rceil \f$ using
* integer arithmetic.
*
* @param a An integer
* @param b Another integer
*
* @return (\a a / \a b) rounded up to the nearest integer.
*/
#define div_ceil(a, b) (((a) + (b) - 1) / (b))
/**
* @brief Sets the WatchDog Timer Control register to the \a ctrl value thanks
* to the WatchDog Timer key.
*
* @param ctrl Value to set the WatchDog Timer Control register to.
*/
static ALWAYS_INLINE void wdt_set_ctrl(uint32_t ctrl)
{
volatile uint32_t dly;
/** Calculate delay for internal synchronization
* see 45.1.3 WDT errata
*/
dly = div_ceil(48000000 * 2, 115000);
dly >>= 3; /* ~8 cycles for one while loop */
while (dly--) {
;
}
WDT->CTRL = ctrl | WDT_CTRL_KEY(WDT_FIRST_KEY);
WDT->CTRL = ctrl | WDT_CTRL_KEY(WDT_SECOND_KEY);
}
#define XTAL_FREQ 12000000
#define NR_PLLS 1
#define PLL_MAX_STARTUP_CYCLES (SCIF_PLL_PLLCOUNT_Msk >> SCIF_PLL_PLLCOUNT_Pos)
/**
* Fcpu = 48MHz
* Fpll = (Fclk * PLL_mul) / PLL_div
*/
#define PLL0_MUL (192000000 / XTAL_FREQ)
#define PLL0_DIV 4
static inline bool pll_is_locked(uint32_t pll_id)
{
return !!(SCIF->PCLKSR & (1U << (6 + pll_id)));
}
static inline bool osc_is_ready(uint8_t id)
{
switch (id) {
case OSC_ID_OSC0:
return !!(SCIF->PCLKSR & SCIF_PCLKSR_OSC0RDY);
case OSC_ID_OSC32:
return !!(BSCIF->PCLKSR & BSCIF_PCLKSR_OSC32RDY);
case OSC_ID_RC32K:
return !!(BSCIF->RC32KCR & (BSCIF_RC32KCR_EN));
case OSC_ID_RC80M:
return !!(SCIF->RC80MCR & (SCIF_RC80MCR_EN));
case OSC_ID_RCFAST:
return !!(SCIF->RCFASTCFG & (SCIF_RCFASTCFG_EN));
case OSC_ID_RC1M:
return !!(BSCIF->RC1MCR & (BSCIF_RC1MCR_CLKOE));
case OSC_ID_RCSYS:
/* RCSYS is always ready */
return true;
default:
/* unhandled_case(id); */
return false;
}
}
/**
* The PLL options #PLL_OPT_VCO_RANGE_HIGH and #PLL_OPT_OUTPUT_DIV will
* be set automatically based on the calculated target frequency.
*/
static inline uint32_t pll_config_init(uint32_t divide, uint32_t mul)
{
#define SCIF0_PLL_VCO_RANGE1_MAX_FREQ 240000000
#define SCIF_PLL0_VCO_RANGE1_MIN_FREQ 160000000
#define SCIF_PLL0_VCO_RANGE0_MAX_FREQ 180000000
#define SCIF_PLL0_VCO_RANGE0_MIN_FREQ 80000000
/* VCO frequency range is 160-240 MHz (80-180 MHz if unset) */
#define PLL_OPT_VCO_RANGE_HIGH 0
/* Divide output frequency by two */
#define PLL_OPT_OUTPUT_DIV 1
/* The threshold above which to set the #PLL_OPT_VCO_RANGE_HIGH option */
#define PLL_VCO_LOW_THRESHOLD ((SCIF_PLL0_VCO_RANGE1_MIN_FREQ \
+ SCIF_PLL0_VCO_RANGE0_MAX_FREQ) / 2)
#define PLL_MIN_HZ 40000000
#define PLL_MAX_HZ 240000000
#define MUL_MIN 2
#define MUL_MAX 16
#define DIV_MIN 0
#define DIV_MAX 15
uint32_t pll_value;
uint32_t vco_hz;
/* Calculate internal VCO frequency */
vco_hz = XTAL_FREQ * mul;
vco_hz /= divide;
pll_value = 0;
/* Bring the internal VCO frequency up to the minimum value */
if ((vco_hz < PLL_MIN_HZ * 2) && (mul <= 8)) {
mul *= 2;
vco_hz *= 2;
pll_value |= (1U << (SCIF_PLL_PLLOPT_Pos +
PLL_OPT_OUTPUT_DIV));
}
/* Set VCO frequency range according to calculated value */
if (vco_hz >= PLL_VCO_LOW_THRESHOLD) {
pll_value |= 1U << (SCIF_PLL_PLLOPT_Pos +
PLL_OPT_VCO_RANGE_HIGH);
}
pll_value |= ((mul - 1) << SCIF_PLL_PLLMUL_Pos) |
(divide << SCIF_PLL_PLLDIV_Pos) |
(PLL_MAX_STARTUP_CYCLES << SCIF_PLL_PLLCOUNT_Pos);
return pll_value;
}
static inline void flashcalw_set_wait_state(uint32_t wait_state)
{
HFLASHC->FCR = (HFLASHC->FCR & ~FLASHCALW_FCR_FWS) |
(wait_state ?
FLASHCALW_FCR_FWS_1 :
FLASHCALW_FCR_FWS_0);
}
static inline bool flashcalw_is_ready(void)
{
return ((HFLASHC->FSR & FLASHCALW_FSR_FRDY) != 0);
}
static inline void flashcalw_issue_command(uint32_t command, int page_number)
{
uint32_t time;
flashcalw_is_ready();
time = HFLASHC->FCMD;
/* Clear the command bitfield. */
time &= ~FLASHCALW_FCMD_CMD_Msk;
if (page_number >= 0) {
time = (FLASHCALW_FCMD_KEY_KEY |
FLASHCALW_FCMD_PAGEN(page_number) | command);
} else {
time |= (FLASHCALW_FCMD_KEY_KEY | command);
}
HFLASHC->FCMD = time;
flashcalw_is_ready();
}
/**
* @brief Setup various clock on SoC at boot time.
*
* Setup the SoC clocks according to section 28.12 in datasheet.
*
* Setup Slow, Main, PLLA, Processor and Master clocks during the device boot.
* It is assumed that the relevant registers are at their reset value.
*/
static ALWAYS_INLINE void clock_init(void)
{
/* Disable PicoCache and Enable HRAMC1 as extended RAM */
soc_pmc_peripheral_enable(
PM_CLOCK_MASK(PM_CLK_GRP_HSB, SYSCLK_HRAMC1_DATA));
soc_pmc_peripheral_enable(
PM_CLOCK_MASK(PM_CLK_GRP_PBB, SYSCLK_HRAMC1_REGS));
HCACHE->CTRL = HCACHE_CTRL_CEN_NO;
while (HCACHE->SR & HCACHE_SR_CSTS_EN) {
;
}
/* Enable PLL */
if (!pll_is_locked(0)) {
/* This assumes external 12MHz Crystal */
SCIF->UNLOCK = SCIF_UNLOCK_KEY(0xAAu) |
SCIF_UNLOCK_ADDR((uint32_t)&SCIF->OSCCTRL0 -
(uint32_t)SCIF);
SCIF->OSCCTRL0 = SCIF_OSCCTRL0_STARTUP(2) |
SCIF_OSCCTRL0_GAIN(3) |
SCIF_OSCCTRL0_MODE |
SCIF_OSCCTRL0_OSCEN;
while (!osc_is_ready(OSC_ID_OSC0)) {
;
}
uint32_t pll_config = pll_config_init(PLL0_DIV,
PLL0_MUL);
SCIF->UNLOCK = SCIF_UNLOCK_KEY(0xAAu) |
SCIF_UNLOCK_ADDR((uint32_t)&SCIF->PLL[0] -
(uint32_t)SCIF);
SCIF->PLL[0] = pll_config | SCIF_PLL_PLLEN;
while (!pll_is_locked(0)) {
;
}
}
/** Set a flash wait state depending on the new cpu frequency.
*/
flashcalw_set_wait_state(1);
flashcalw_issue_command(FLASHCALW_FCMD_CMD_HSEN, -1);
/** Set Clock CPU/BUS dividers
*/
PM->UNLOCK = PM_UNLOCK_KEY(0xAAu) |
PM_UNLOCK_ADDR((uint32_t)&PM->CPUSEL - (uint32_t)PM);
PM->CPUSEL = PM_CPUSEL_CPUSEL(0);
PM->UNLOCK = PM_UNLOCK_KEY(0xAAu) |
PM_UNLOCK_ADDR((uint32_t)&PM->PBASEL - (uint32_t)PM);
PM->PBASEL = PM_PBASEL_PBSEL(0);
PM->UNLOCK = PM_UNLOCK_KEY(0xAAu) |
PM_UNLOCK_ADDR((uint32_t)&PM->PBBSEL - (uint32_t)PM);
PM->PBBSEL = PM_PBBSEL_PBSEL(0);
PM->UNLOCK = PM_UNLOCK_KEY(0xAAu) |
PM_UNLOCK_ADDR((uint32_t)&PM->PBCSEL - (uint32_t)PM);
PM->PBCSEL = PM_PBCSEL_PBSEL(0);
PM->UNLOCK = PM_UNLOCK_KEY(0xAAu) |
PM_UNLOCK_ADDR((uint32_t)&PM->PBDSEL - (uint32_t)PM);
PM->PBDSEL = PM_PBDSEL_PBSEL(0);
/** Set PLL0 as source clock
*/
PM->UNLOCK = PM_UNLOCK_KEY(0xAAu) |
PM_UNLOCK_ADDR((uint32_t)&PM->MCCTRL - (uint32_t)PM);
PM->MCCTRL = OSC_SRC_PLL0;
}
/**
* @brief Perform basic hardware initialization at boot.
*
* This needs to be run from the very beginning.
* So the init priority has to be 0 (zero).
*
* @return 0
*/
static int atmel_sam4l_init(const struct device *arg)
{
uint32_t key;
ARG_UNUSED(arg);
key = irq_lock();
#if defined(CONFIG_WDT_DISABLE_AT_BOOT)
wdt_set_ctrl(WDT->CTRL & ~WDT_CTRL_EN);
while (WDT->CTRL & WDT_CTRL_EN) {
;
}
#endif
/* Setup system clocks. */
clock_init();
/*
* Install default handler that simply resets the CPU
* if configured in the kernel, NOP otherwise.
*/
NMI_INIT();
irq_unlock(key);
return 0;
}
SYS_INIT(atmel_sam4l_init, PRE_KERNEL_1, 0);