zephyr/drivers/clock_control/clock_control_mchp_xec.c

652 lines
17 KiB
C

/*
* Copyright (c) 2021 Microchip Technology Inc.
*
* SPDX-License-Identifier: Apache-2.0
*/
#define DT_DRV_COMPAT microchip_xec_pcr
#include <soc.h>
#include <zephyr/arch/cpu.h>
#include <zephyr/arch/arm/aarch32/cortex_m/cmsis.h>
#include <zephyr/drivers/clock_control.h>
#include <zephyr/drivers/clock_control/mchp_xec_clock_control.h>
#include <zephyr/dt-bindings/clock/mchp_xec_pcr.h>
#include <zephyr/logging/log.h>
LOG_MODULE_REGISTER(clock_control_xec, LOG_LEVEL_ERR);
#define CLK32K_SIL_OSC_DELAY 256
#define CLK32K_PLL_LOCK_WAIT (16 * 1024)
#define CLK32K_PIN_WAIT 4096
#define CLK32K_XTAL_WAIT (16 * 1024)
#define CLK32K_XTAL_MON_WAIT (64 * 1024)
/*
* Counter checks:
* 32KHz period counter minimum for pass/fail: 16-bit
* 32KHz period counter maximum for pass/fail: 16-bit
* 32KHz duty cycle variation max for pass/fail: 16-bit
* 32KHz valid count minimum: 8-bit
*
* 32768 Hz period is 30.518 us
* HW count resolution is 48 MHz.
* One 32KHz clock pulse = 1464.84 48 MHz counts.
*/
#define CNT32K_TMIN 1435
#define CNT32K_TMAX 1495
#define CNT32K_DUTY_MAX 74
#define CNT32K_VAL_MIN 4
#define DEST_PLL 0
#define DEST_PERIPH 1
#define CLK32K_FLAG_CRYSTAL_SE BIT(0)
#define CLK32K_FLAG_PIN_FB_CRYSTAL BIT(1)
#define PCR_PERIPH_RESET_SPIN 8u
#define HIBTIMER_10_MS 328u
#define HIBTIMER_300_MS 9830u
#define PCR_XEC_REG_BASE \
((struct pcr_regs *)(DT_REG_ADDR(DT_NODELABEL(pcr))))
#define HIBTIMER_0_XEC_REG_BASE \
((struct htmr_regs *)(DT_REG_ADDR(DT_NODELABEL(hibtimer0))))
#define GIRQ23_XEC_REG_BASE \
((struct girq_regs *)(DT_REG_ADDR(DT_NODELABEL(girq23))))
enum clk32k_src {
CLK32K_SRC_SIL_OSC = 0,
CLK32K_SRC_CRYSTAL,
CLK32K_SRC_MAX
};
enum clk32k_dest { CLK32K_DEST_PLL = 0, CLK32K_DEST_PERIPH, CLK32K_DEST_MAX };
/* Driver config */
struct xec_pcr_config {
uintptr_t pcr_base; /* pcr base address */
uintptr_t vbr_base; /* vbat registers base address */
};
/* Driver convenience defines */
#define PCR_NODE_LBL DT_NODELABEL(pcr)
#define XEC_CORE_CLK_DIV \
DT_PROP_OR(PCR_NODE_LBL, core_clk_div, CONFIG_SOC_MEC172X_PROC_CLK_DIV)
#define DRV_CONFIG(dev) \
((const struct xec_pcr_config *)(dev)->config)
#define XEC_PCR_REGS_BASE(dev) \
(struct pcr_regs *)(DRV_CONFIG(dev)->pcr_base)
#define XEC_VBATR_REGS_BASE(dev) \
(struct vbatr_regs *)(DRV_CONFIG(dev)->vbr_base)
/*
* In early Zephyr initialization we don't have timer services. Also, the SoC
* may be running on its ring oscillator (+/- 50% accuracy). Configuring the
* SoC's clock subsystem requires wait/delays. We implement a simple delay
* by writing to a read-only hardware register in the PCR block.
*/
static uint32_t spin_delay(struct pcr_regs *pcr, uint32_t cnt)
{
uint32_t n;
for (n = 0U; n < cnt; n++) {
pcr->OSC_ID = n;
}
return n;
}
/*
* Make sure PCR sleep enables are clear except for crypto
* which do not have internal clock gating.
*/
static void pcr_slp_init(struct pcr_regs *pcr)
{
pcr->SYS_SLP_CTRL = 0U;
SCB->SCR &= ~BIT(2);
for (int i = 0; i < MCHP_MAX_PCR_SCR_REGS; i++) {
pcr->SLP_EN[i] = 0U;
}
pcr->SLP_EN[3] = MCHP_PCR3_CRYPTO_MASK;
}
static bool is_sil_osc_enabled(struct vbatr_regs *vbr)
{
if (vbr->CLK32_SRC & MCHP_VBATR_CS_SO_EN) {
return true;
}
return false;
}
static void enable_sil_osc(struct vbatr_regs *vbr)
{
vbr->CLK32_SRC |= MCHP_VBATR_CS_SO_EN;
}
/* caller has enabled internal silicon 32 KHz oscillator */
static void hib_timer_delay(uint16_t hib_timer_count)
{
struct htmr_regs *htmr0 = HIBTIMER_0_XEC_REG_BASE;
struct girq_regs *girq23 = GIRQ23_XEC_REG_BASE;
htmr0->PRLD = 0; /* disable */
htmr0->CTRL = 0; /* 32k time base */
girq23->SRC = BIT(16); /* clear hibernation timer 0 status */
htmr0->PRLD = hib_timer_count;
if (hib_timer_count == 0) {
return;
}
while ((girq23->SRC & BIT(16)) == 0) {
;
}
girq23->SRC = BIT(16);
htmr0->PRLD = 0; /* disable */
}
/*
* Start external 32 KHz crystal.
* Assumes peripheral clocks source is Silicon OSC.
* If current configuration matches desired crystal configuration do nothing.
* NOTE: Crystal requires ~300 ms to stabilize.
*/
static int enable_32k_crystal(const struct device *dev, uint32_t flags)
{
struct vbatr_regs *const vbr = XEC_VBATR_REGS_BASE(dev);
uint32_t vbcs = vbr->CLK32_SRC;
uint32_t cfg = MCHP_VBATR_CS_XTAL_EN;
if (flags & CLK32K_FLAG_CRYSTAL_SE) {
cfg |= MCHP_VBATR_CS_XTAL_SE;
}
if ((vbcs & cfg) == cfg) {
return 0;
}
/* Configure crystal connection before enabling the crystal. */
vbr->CLK32_SRC &= ~(MCHP_VBATR_CS_XTAL_SE | MCHP_VBATR_CS_XTAL_DHC |
MCHP_VBATR_CS_XTAL_CNTR_MSK);
if (flags & CLK32K_FLAG_CRYSTAL_SE) {
vbr->CLK32_SRC |= MCHP_VBATR_CS_XTAL_SE;
}
/* Set crystal gain */
vbr->CLK32_SRC |= MCHP_VBATR_CS_XTAL_CNTR_DG;
/* enable crystal */
vbr->CLK32_SRC |= MCHP_VBATR_CS_XTAL_EN;
/* wait for crystal stabilization */
hib_timer_delay(HIBTIMER_300_MS);
/* turn off crystal high startup current */
vbr->CLK32_SRC |= MCHP_VBATR_CS_XTAL_DHC;
return 0;
}
/*
* Use PCR clock monitor hardware to test crystal output.
* Requires crystal to have stabilized after enable.
* When enabled the clock monitor hardware measures high/low, edges, and
* duty cycle and compares to programmed limits.
*/
static int check_32k_crystal(const struct device *dev)
{
struct pcr_regs *const pcr = XEC_PCR_REGS_BASE(dev);
struct htmr_regs *htmr0 = HIBTIMER_0_XEC_REG_BASE;
struct girq_regs *girq23 = GIRQ23_XEC_REG_BASE;
uint32_t status = 0;
int rc = 0;
htmr0->PRLD = 0;
htmr0->CTRL = 0;
girq23->SRC = BIT(16);
pcr->CNT32K_CTRL = 0U;
pcr->CLK32K_MON_IEN = 0U;
pcr->CLK32K_MON_ISTS = MCHP_PCR_CLK32M_ISTS_MASK;
pcr->CNT32K_PER_MIN = CNT32K_TMIN;
pcr->CNT32K_PER_MAX = CNT32K_TMAX;
pcr->CNT32K_DV_MAX = CNT32K_DUTY_MAX;
pcr->CNT32K_VALID_MIN = CNT32K_VAL_MIN;
pcr->CNT32K_CTRL =
MCHP_PCR_CLK32M_CTRL_PER_EN | MCHP_PCR_CLK32M_CTRL_DC_EN |
MCHP_PCR_CLK32M_CTRL_VAL_EN | MCHP_PCR_CLK32M_CTRL_CLR_CNT;
rc = -ETIMEDOUT;
htmr0->PRLD = HIBTIMER_10_MS;
status = pcr->CLK32K_MON_ISTS;
while ((girq23->SRC & BIT(16)) == 0) {
if (status == (MCHP_PCR_CLK32M_ISTS_PULSE_RDY |
MCHP_PCR_CLK32M_ISTS_PASS_PER |
MCHP_PCR_CLK32M_ISTS_PASS_DC |
MCHP_PCR_CLK32M_ISTS_VALID)) {
rc = 0;
break;
}
if (status & (MCHP_PCR_CLK32M_ISTS_FAIL |
MCHP_PCR_CLK32M_ISTS_STALL)) {
rc = -EBUSY;
break;
}
status = pcr->CLK32K_MON_ISTS;
}
pcr->CNT32K_CTRL = 0u;
htmr0->PRLD = 0;
girq23->SRC = BIT(16);
return rc;
}
/*
* Set the clock source for either PLL or Peripheral-32K clock domain.
* The source must be a stable 32 KHz input: internal silicon oscillator,
* external crystal (parallel or single ended connection), or a 50% duty cycle
* waveform on the 32KHZ_PIN. The driver does not implement 32KHZ_PIN support
* at this time.
*/
static void connect_32k_source(const struct device *dev, enum clk32k_src src,
enum clk32k_dest dest, uint32_t flags)
{
struct pcr_regs *const pcr = XEC_PCR_REGS_BASE(dev);
struct vbatr_regs *const vbr = XEC_VBATR_REGS_BASE(dev);
if (dest == CLK32K_DEST_PLL) {
switch (src) {
case CLK32K_SRC_SIL_OSC:
pcr->CLK32K_SRC_VTR = MCHP_PCR_VTR_32K_SRC_SILOSC;
break;
case CLK32K_SRC_CRYSTAL:
pcr->CLK32K_SRC_VTR = MCHP_PCR_VTR_32K_SRC_XTAL;
break;
default: /* do not touch HW */
break;
}
} else if (dest == CLK32K_DEST_PERIPH) {
uint32_t vbcs = vbr->CLK32_SRC & ~(MCHP_VBATR_CS_PCS_MSK);
switch (src) {
case CLK32K_SRC_SIL_OSC:
vbr->CLK32_SRC = vbcs | MCHP_VBATR_CS_PCS_VTR_VBAT_SO;
break;
case CLK32K_SRC_CRYSTAL:
vbr->CLK32_SRC = vbcs | MCHP_VBATR_CS_PCS_VTR_VBAT_XTAL;
break;
default: /* do not touch HW */
break;
}
}
}
/*
* This routine checks if the PLL is locked to its input source. Minimum lock
* time is 3.3 ms. Lock time can be larger when the source is an external
* crystal. Crystal cold start times may vary greatly based on many factors.
* Crystals do not like being power cycled.
*/
static int pll_wait_lock(struct pcr_regs *const pcr, uint32_t wait_cnt)
{
while (!(pcr->OSC_ID & MCHP_PCR_OSC_ID_PLL_LOCK)) {
if (wait_cnt == 0) {
return -ETIMEDOUT;
}
--wait_cnt;
}
return 0;
}
/*
* MEC172x has two 32 KHz clock domains
* PLL domain: 32 KHz clock input for PLL to produce 96 MHz and 48 MHz clocks
* Peripheral domain: 32 KHz clock for subset of peripherals.
* Each domain 32 KHz clock input can be from one of the following sources:
* Internal Silicon oscillator: +/- 2%
* External Crystal connected as parallel or single ended
* External 32KHZ_PIN 50% duty cycle waveform with fall back to either
* Silicon OSC or crystal when 32KHZ_PIN signal goes away or VTR power rail
* goes off.
* At chip reset the PLL is held in reset and the +/- 50% ring oscillator is
* the main clock.
* If no VBAT reset occurs the VBAT 32 KHz source register maintains its state.
*/
static int soc_clk32_init(const struct device *dev,
enum clk32k_src pll_clk_src,
enum clk32k_src periph_clk_src,
uint32_t flags)
{
struct pcr_regs *const pcr = XEC_PCR_REGS_BASE(dev);
struct vbatr_regs *const vbr = XEC_VBATR_REGS_BASE(dev);
int rc = 0;
/* disable PCR 32K monitor and clear counters */
pcr->CNT32K_CTRL = MCHP_PCR_CLK32M_CTRL_CLR_CNT;
pcr->CLK32K_MON_ISTS = MCHP_PCR_CLK32M_ISTS_MASK;
pcr->CLK32K_MON_IEN = 0;
if (!is_sil_osc_enabled(vbr)) {
enable_sil_osc(vbr);
spin_delay(pcr, CLK32K_SIL_OSC_DELAY);
}
/* Default to 32KHz Silicon OSC for PLL and peripherals */
connect_32k_source(dev, CLK32K_SRC_SIL_OSC, CLK32K_DEST_PLL, 0);
connect_32k_source(dev, CLK32K_SRC_SIL_OSC, CLK32K_DEST_PERIPH, 0);
rc = pll_wait_lock(pcr, CLK32K_PLL_LOCK_WAIT);
if (rc) {
return rc;
}
/* We only allow Silicon OSC or Crystal as a source. */
if ((pll_clk_src == CLK32K_SRC_CRYSTAL) ||
(periph_clk_src == CLK32K_SRC_CRYSTAL)) {
enable_32k_crystal(dev, flags);
rc = check_32k_crystal(dev);
if (rc) {
/* disable crystal */
vbr->CLK32_SRC &= ~(MCHP_VBATR_CS_XTAL_EN);
return rc;
}
if (pll_clk_src == CLK32K_SRC_CRYSTAL) {
connect_32k_source(dev, CLK32K_SRC_CRYSTAL,
CLK32K_DEST_PLL, flags);
}
if (periph_clk_src == CLK32K_SRC_CRYSTAL) {
connect_32k_source(dev, CLK32K_SRC_CRYSTAL,
CLK32K_DEST_PERIPH, flags);
}
rc = pll_wait_lock(pcr, CLK32K_PLL_LOCK_WAIT);
}
return rc;
}
/*
* MEC172x Errata document DS80000913C
* Programming the PCR clock divider that divides the clock input to the ARM
* Cortex-M4 may cause a clock glitch. The recommended work-around is to
* issue four NOP instruction before and after the write to the PCR processor
* clock control register. The final four NOP instructions are followed by
* data and instruction barriers to flush the Cortex-M4's pipeline.
* NOTE: Zephyr provides inline functions for Cortex-Mx NOP but not for
* data and instruction barrier instructions. Caller's should only invoke this
* function with interrupts locked.
*/
static void xec_clock_control_core_clock_divider_set(uint8_t clkdiv)
{
struct pcr_regs *const pcr =
(struct pcr_regs *)(DT_REG_ADDR(DT_NODELABEL(pcr)));
arch_nop();
arch_nop();
arch_nop();
arch_nop();
pcr->PROC_CLK_CTRL = (uint32_t)clkdiv;
arch_nop();
arch_nop();
arch_nop();
arch_nop();
__DSB();
__ISB();
}
/*
* PCR peripheral sleep enable allows the clocks to a specific peripheral to
* be gated off if the peripheral is not requesting a clock.
* slp_idx = zero based index into 32-bit PCR sleep enable registers.
* slp_pos = bit position in the register
* slp_en if non-zero set the bit else clear the bit
*/
int z_mchp_xec_pcr_periph_sleep(uint8_t slp_idx, uint8_t slp_pos,
uint8_t slp_en)
{
struct pcr_regs *regs = PCR_XEC_REG_BASE;
if ((slp_idx >= MCHP_MAX_PCR_SCR_REGS) || (slp_pos >= 32)) {
return -EINVAL;
}
if (slp_en) {
regs->SLP_EN[slp_idx] |= BIT(slp_pos);
} else {
regs->SLP_EN[slp_idx] &= ~BIT(slp_pos);
}
return 0;
}
/* clock control driver API implementation */
static int xec_cc_on(const struct device *dev,
clock_control_subsys_t sub_system,
bool turn_on)
{
struct pcr_regs *const pcr = XEC_PCR_REGS_BASE(dev);
struct mchp_xec_pcr_clk_ctrl *cc =
(struct mchp_xec_pcr_clk_ctrl *)sub_system;
uint16_t pcr_idx = 0;
uint16_t bitpos = 0;
if (!cc) {
return -EINVAL;
}
switch (MCHP_XEC_CLK_SRC_GET(cc->pcr_info)) {
case MCHP_XEC_PCR_CLK_CORE:
case MCHP_XEC_PCR_CLK_BUS:
break;
case MCHP_XEC_PCR_CLK_CPU:
if (cc->pcr_info & MCHP_XEC_CLK_CPU_MASK) {
uint32_t lock = irq_lock();
xec_clock_control_core_clock_divider_set(
cc->pcr_info & MCHP_XEC_CLK_CPU_MASK);
irq_unlock(lock);
} else {
return -EINVAL;
}
break;
case MCHP_XEC_PCR_CLK_PERIPH:
case MCHP_XEC_PCR_CLK_PERIPH_FAST:
pcr_idx = MCHP_XEC_PCR_SCR_GET_IDX(cc->pcr_info);
bitpos = MCHP_XEC_PCR_SCR_GET_BITPOS(cc->pcr_info);
if (pcr_idx >= MCHP_MAX_PCR_SCR_REGS) {
return -EINVAL;
}
if (turn_on) {
pcr->SLP_EN[pcr_idx] &= ~BIT(bitpos);
} else {
pcr->SLP_EN[pcr_idx] |= BIT(bitpos);
}
break;
case MCHP_XEC_PCR_CLK_PERIPH_SLOW:
if (turn_on) {
pcr->SLOW_CLK_CTRL =
cc->pcr_info & MCHP_XEC_CLK_SLOW_MASK;
} else {
pcr->SLOW_CLK_CTRL = 0;
}
break;
default:
return -EINVAL;
}
return 0;
}
/*
* Turn on requested clock source.
* Core, CPU, and Bus clocks are always on except in deep sleep state.
* Peripheral clocks can be gated off if the peripheral's PCR sleep enable
* is set and the peripheral indicates it does not need a clock by clearing
* its PCR CLOCK_REQ read-only status.
* Peripheral slow clock my be turned on by writing a non-zero divider value
* to its PCR control register.
*/
static int xec_clock_control_on(const struct device *dev,
clock_control_subsys_t sub_system)
{
return xec_cc_on(dev, sub_system, true);
}
/*
* Turn off clock source.
* Core, CPU, and Bus clocks are always on except in deep sleep when PLL is
* turned off. Exception is 32 KHz clock.
* Peripheral clocks are gated off when the peripheral's sleep enable is set
* and the peripheral indicates is no longer needs a clock by de-asserting
* its read-only PCR CLOCK_REQ bit.
* Peripheral slow clock can be turned off by writing 0 to its control register.
*/
static inline int xec_clock_control_off(const struct device *dev,
clock_control_subsys_t sub_system)
{
return xec_cc_on(dev, sub_system, false);
}
/*
* MEC172x clock subsystem:
* Two main clock domains: PLL and Peripheral-32K. Each domain's 32 KHz source
* can be selected from one of three inputs:
* internal silicon OSC +/- 2% accuracy
* external crystal connected parallel or single ended
* external 32 KHz 50% duty cycle waveform on 32KHZ_IN pin.
* PLL domain supplies 96 MHz, 48 MHz, and other high speed clocks to all
* peripherals except those in the Peripheral-32K clock domain. The slow clock
* is derived from the 48 MHz produced by the PLL.
* ARM Cortex-M4 core input: 96MHz
* AHB clock input: 48 MHz
* Fast AHB peripherals: 96 MHz internal and 48 MHz AHB interface.
* Slow clock peripherals: PWM, TACH, PROCHOT
* Peripheral-32K domain peripherals:
* WDT, RTC, RTOS timer, hibernation timers, week timer
*
* Peripherals using both PLL and 32K clock domains:
* BBLED, RPMFAN
*/
static int xec_clock_control_get_subsys_rate(const struct device *dev,
clock_control_subsys_t sub_system,
uint32_t *rate)
{
struct pcr_regs *const pcr = XEC_PCR_REGS_BASE(dev);
uint32_t bus = (uint32_t)sub_system;
uint32_t temp = 0;
switch (bus) {
case MCHP_XEC_PCR_CLK_CORE:
case MCHP_XEC_PCR_CLK_PERIPH_FAST:
*rate = MHZ(96);
break;
case MCHP_XEC_PCR_CLK_CPU:
/* if PCR PROC_CLK_CTRL is 0 the chip is not running */
*rate = MHZ(96) / pcr->PROC_CLK_CTRL;
break;
case MCHP_XEC_PCR_CLK_BUS:
case MCHP_XEC_PCR_CLK_PERIPH:
*rate = MHZ(48);
break;
case MCHP_XEC_PCR_CLK_PERIPH_SLOW:
temp = pcr->SLOW_CLK_CTRL;
if (pcr->SLOW_CLK_CTRL) {
*rate = MHZ(48) / temp;
} else {
*rate = 0; /* slow clock off */
}
break;
default:
*rate = 0;
return -EINVAL;
}
return 0;
}
#if defined(CONFIG_PM)
void mchp_xec_clk_ctrl_sys_sleep_enable(bool is_deep)
{
struct pcr_regs *const pcr =
(struct pcr_regs *)(DT_REG_ADDR(DT_NODELABEL(pcr)));
uint32_t sys_sleep_mode = MCHP_PCR_SYS_SLP_CTRL_SLP_ALL;
if (is_deep) {
sys_sleep_mode |= MCHP_PCR_SYS_SLP_CTRL_SLP_HEAVY;
}
SCB->SCR |= BIT(2);
pcr->SYS_SLP_CTRL = sys_sleep_mode;
}
void mchp_xec_clk_ctrl_sys_sleep_disable(void)
{
struct pcr_regs *const pcr =
(struct pcr_regs *)(DT_REG_ADDR(DT_NODELABEL(pcr)));
pcr->SYS_SLP_CTRL = 0;
SCB->SCR &= ~BIT(2);
}
#endif
/* Clock controller driver registration */
static struct clock_control_driver_api xec_clock_control_api = {
.on = xec_clock_control_on,
.off = xec_clock_control_off,
.get_rate = xec_clock_control_get_subsys_rate,
};
static int xec_clock_control_init(const struct device *dev)
{
int rc = 0;
uint32_t clk32_flags = 0;
struct pcr_regs *const pcr = XEC_PCR_REGS_BASE(dev);
enum clk32k_src clk_src_pll =
DT_PROP_OR(PCR_NODE_LBL, pll_32k_src, CLK32K_SRC_SIL_OSC);
enum clk32k_src clk_src_periph =
DT_PROP_OR(PCR_NODE_LBL, periph_32k_src, CLK32K_SRC_SIL_OSC);
pcr_slp_init(pcr);
rc = soc_clk32_init(dev, clk_src_pll, clk_src_periph, clk32_flags);
__ASSERT(rc == 0, "XEC: PLL and 32 KHz clock initialization failed");
xec_clock_control_core_clock_divider_set(XEC_CORE_CLK_DIV);
return rc;
}
const struct xec_pcr_config xec_config = {
.pcr_base = DT_INST_REG_ADDR_BY_IDX(0, 0),
.vbr_base = DT_INST_REG_ADDR_BY_IDX(0, 1),
};
DEVICE_DT_INST_DEFINE(0,
&xec_clock_control_init,
NULL,
NULL, &xec_config,
PRE_KERNEL_1,
CONFIG_CLOCK_CONTROL_INIT_PRIORITY,
&xec_clock_control_api);