Skip to content

Latest commit

 

History

History
754 lines (628 loc) · 27.5 KB

a10c_99.md

File metadata and controls

754 lines (628 loc) · 27.5 KB
Raw
ARM10C 99주차
일시 : 2015.04.18 (99주차)
모임명 : NAVER개발자커뮤니티지원_IAMROOT.ORG_10차ARM-C
장소 : 토즈 타워점
장소지원 : NAVER 개발자 커뮤니티 지원 프로그램
참여인원 : 3명

============

99주차 진도

  • start_kernel 1 ~/kernel/iamroot/linux-stable/init/main.c
  • time_init 741 ~/kernel/iamroot/linux-stable/init/main.c
  • clocksource_of_init 557 ~/kernel/iamroot/linux-stable/arch/arm/kernel/time.c
    • mct_init_spi 56 ~/kernel/iamroot/linux-stable/drivers/clocksource/clksrc-of.c
      • mct_init_dt 877 ~/kernel/iamroot/linux-stable/drivers/clocksource/exynos_mct.c
        • exynos4_timer_resources 806 ~/kernel/iamroot/linux-stable/drivers/clocksource/exynos_mct.c
          • exynos4_local_timer_setup 714 ~/kernel/iamroot/linux-stable/drivers/clocksource/exynos_mct.c
            • clockevents_config_and_register 525 ~/kernel/iamroot/linux-stable/drivers/clocksource/exynos_mct.c
              • clockevents_register_device 580 ~/kernel/iamroot/linux-stable/kernel/time/clockevents.c
                • tick_check_new_device 485 ~/kernel/iamroot/linux-stable/kernel/time/clockevents.c
                  • tick_setup_device 385 tick_setup_device(td, newdev, cpu, cpumask_of(cpu));
                    • ktime_get 198 tick_next_period = ktime_get();

main.c::start_kernel()->time_init()

  • called: start_kernel()->time_init()
asmlinkage void __init start_kernel(void)
{
...
	early_irq_init();
	// irq_desc 0 ~ 15 까지의 object을 할당 받고 초기화를 수행
	// allocated_irqs에 bit를 1로 세팅하고 radix tree에 각 irq_desc를 노트로 추가

	init_IRQ();
	// gic, combiner이 사용할 메모리 할당과 자료 구조 설정,
	// gic irq (0~15), combiner irq (32~63) interrupt 를 enable 시킴

	tick_init();
	// tick 관련 mask 변수를 0으로 초기화 수행

	init_timers();
	// boot_tvec_bases의 맴버 값을 초기화하고 timers_nb를 cpu_notifier 에 등록,
	// softirq_vec[1] 에 run_timer_softirq 등록하여 초기화 수행

	hrtimers_init();
	// hrtimer_bases의 맴버 값을 초기화하고 hrtimers_nb를 cpu_notifier 에 등록,
	// softirq_vec[8] 에 run_hrtimer_softirq 등록하여 초기화 수행

	softirq_init();
	// tasklet_vec, tasklet_hi_vec 맴버 값을 초기화하고,
	// softirq_vec[6]에 tasklet_action, softirq_vec[0]에 tasklet_hi_action 등록하여 초기화 수행

	timekeeping_init();
	// ntp 관련 전역변수 초기화, timekeeper, shadow_timekeeper의 맴버값 초기화 수행

	time_init();

time.c::time_init()->of_clk_init(NULL)

  • called: start_kernel()->time_init()->of_clk_init()
// ARM10C 20150103
void __init time_init(void)
{
	// machine_desc->init_time: __mach_desc_EXYNOS5_DT.init_time: NULL
	if (machine_desc->init_time) {
		machine_desc->init_time();
	} else {
#ifdef CONFIG_COMMON_CLK // CONFIG_COMMON_CLK=y
		of_clk_init(NULL);
#endif
		clocksource_of_init();
  • called: start_kernel()->time_init()->clocksource_of_init()

clksrc-of.c::time_init()->clocksource_of_init()

  • called: start_kernel()->time_init()->clocksource_of_init()
// ARM10C 20150307
void __init clocksource_of_init(void)
{
	struct device_node *np;
	const struct of_device_id *match;
	clocksource_of_init_fn init_func;

	for_each_matching_node_and_match(np, __clksrc_of_table, &match) {
	// for (np = of_find_matching_node_and_match(NULL, __clksrc_of_table, &match);
	//      np; np = of_find_matching_node_and_match(np, __clksrc_of_table, &match))

		// np: devtree에서 allnext로 순회 하면서 찾은 mct node의 주소, match: __clksrc_of_table_exynos4210

		// np: devtree에서 allnext로 순회 하면서 찾은 mct node의 주소
		// of_device_is_available(devtree에서 allnext로 순회 하면서 찾은 mct node의 주소): 1
		if (!of_device_is_available(np))
			continue;

		// match->data: __clksrc_of_table_exynos4210.data: mct_init_spi
		init_func = match->data;
		// init_func: mct_init_spi

		// init_func: mct_init_spi
		// np: devtree에서 allnext로 순회 하면서 찾은 mct node의 주소
		// mct_init_spi(devtree에서 allnext로 순회 하면서 찾은 mct node의 주소)
		init_func(np);

3* init_func(np) 에서 호출하는 함수.

  • DTB에 보면 exynos4210-mct 로 mct_init_spi()가 정의되었다.
// ARM10C 20150307
// #define CLOCKSOURCE_OF_DECLARE(exynos4210, "samsung,exynos4210-mct", mct_init_spi):
// static const struct of_device_id __clksrc_of_table_exynos4210 __used __section(__clksrc_of_table)
// = { .compatible = "samsung,exynos4210-mct",
//     .data = (mct_init_spi == (clocksource_of_init_fn)NULL) ? mct_init_spi : mct_init_spi }
CLOCKSOURCE_OF_DECLARE(exynos4210, "samsung,exynos4210-mct", mct_init_spi);

// ARM10C 20150307
// #define CLOCKSOURCE_OF_DECLARE(exynos4412, "samsung,exynos4412-mct", mct_init_ppi):
// static const struct of_device_id __clksrc_of_table_exynos4412 __used __section(__clksrc_of_table)
// = { .compatible = "samsung,exynos4412-mct",
//     .data = (mct_init_ppi == (clocksource_of_init_fn)NULL) ? mct_init_ppi : mct_init_ppi }
CLOCKSOURCE_OF_DECLARE(exynos4412, "samsung,exynos4412-mct", mct_init_ppi);
  • call: start_kernel()->time_init()->clocksource_of_init()->init_func(np)
  • init_func(np);
  • mct_init_spi(devtree에서 allnext로 순회 하면서 찾은 mct node의 주소)

exynos_mct.c::mct_init_spi()

  • called: start_kernel()->time_init()->clocksource_of_init()->init_func(np)
  • init_func(np);
  • // mct_init_spi(devtree에서 allnext로 순회 하면서 찾은 mct node의 주소)
  • init_func(np)->mct_init_spi()
// ARM10C 20150307
// np: devtree에서 allnext로 순회 하면서 찾은 mct node의 주소
static void __init mct_init_spi(struct device_node *np)
{
	// np: devtree에서 allnext로 순회 하면서 찾은 mct node의 주소, MCT_INT_SPI: 0
	return mct_init_dt(np, MCT_INT_SPI);
}
  • call: start_kernel()->time_init()->clocksource_of_init()->init_func(np)
  • // np: devtree에서 allnext로 순회 하면서 찾은 mct node의 주소, MCT_INT_SPI: 0
  • init_func(np):mct_init_spi()->mct_init_dt()

exynos_mct.c::mct_init_dt()

  • called: start_kernel()->time_init()->clocksource_of_init()->init_func(np)
  • // np: devtree에서 allnext로 순회 하면서 찾은 mct node의 주소, MCT_INT_SPI: 0
  • init_func(np):mct_init_spi()->mct_init_dt()
// ARM10C 20150307
// np: devtree에서 allnext로 순회 하면서 찾은 mct node의 주소, MCT_INT_SPI: 0
static void __init mct_init_dt(struct device_node *np, unsigned int int_type)
{
	u32 nr_irqs, i;

	// int_type: 0
	mct_int_type = int_type;
	// mct_int_type: 0

	/* This driver uses only one global timer interrupt */
	// np: devtree에서 allnext로 순회 하면서 찾은 mct node의 주소, MCT_G0_IRQ: 0
	// irq_of_parse_and_map(devtree에서 allnext로 순회 하면서 찾은 mct node의 주소, 0): 347
	mct_irqs[MCT_G0_IRQ] = irq_of_parse_and_map(np, MCT_G0_IRQ);
	// mct_irqs[0]: 347

	// irq_of_parse_and_map(mct node, 0)에서 한일:
	// devtree의 mct node의 interrupt의 property의 값을 dtb에  분석하여 oirq 값을 가져옴
	//
	// (&oirq)->np: combiner node의 주소
	// (&oirq)->args_count: 2
	// (&oirq)->args[0]: 23
	// (&oirq)->args[1]: 3
	//
	// oirq 값을 사용하여 combiner domain에서 virq 값을 찾음
	// virq: 347

	/*
	 * Find out the number of local irqs specified. The local
	 * timer irqs are specified after the four global timer
	 * irqs are specified.
	 */
#ifdef CONFIG_OF // CONFIG_OF=y
	// np: devtree에서 allnext로 순회 하면서 찾은 mct node의 주소
	// of_irq_count(devtree에서 allnext로 순회 하면서 찾은 mct node의 주소): 8
	nr_irqs = of_irq_count(np);
	// nr_irqs: 8
	
	// of_irq_count(mct node)에서 한일:
	// devtree에 등록된 mct node에 irq 의 갯수를 구함
#else
	nr_irqs = 0;
#endif

	// nr_irqs: 8, MCT_L0_IRQ: 4
	for (i = MCT_L0_IRQ; i < nr_irqs; i++)
		// i: 4, np: devtree에서 allnext로 순회 하면서 찾은 mct node의 주소
		// irq_of_parse_and_map(devtree에서 allnext로 순회 하면서 찾은 mct node의 주소, 4): 152
		mct_irqs[i] = irq_of_parse_and_map(np, i);
		// mct_irqs[4]: 152
		
		// irq_of_parse_and_map(mct node, 4)에서 한일:
		// devtree의 mct node의 interrupt의 property의 값을 dtb에  분석하여 oirq 값을 가져옴
		//
		// (&oirq)->np: gic node의 주소
		// (&oirq)->args_count: 3
		// (&oirq)->args[0]: 0
		// (&oirq)->args[1]: 120
		// (&oirq)->args[2]: 0
		//
		// oirq 값을 사용하여 gic domain에서 virq 값을 찾음
		// virq: 152

		// i: 5...7 loop 수행

	// 위 loop의 수행 결과
	// mct_irqs[4]: 152
	// mct_irqs[5]: 153
	// mct_irqs[6]: 154
	// mct_irqs[7]: 155

	// np: devtree에서 allnext로 순회 하면서 찾은 mct node의 주소
	// of_iomap(devtree에서 allnext로 순회 하면서 찾은 mct node의 주소, 0): 0xf0006000
	exynos4_timer_resources(np, of_iomap(np, 0));

// cache의 값을 전부 메모리에 반영

  • call: start_kernel()->time_init()->clocksource_of_init()->init_func(np)
  • // np: devtree에서 allnext로 순회 하면서 찾은 mct node의 주소, MCT_INT_SPI: 0
  • ->init_func(np)->mct_init_spi()->mct_init_dt()
  • exynos4_timer_resources()

exynos_mct.c::exynos4_timer_resources()

  • called: start_kernel()->time_init()->clocksource_of_init()->init_func(np)
  • // np: devtree에서 allnext로 순회 하면서 찾은 mct node의 주소, MCT_INT_SPI: 0
  • ->init_func(np)->mct_init_spi()->mct_init_dt()
  • exynos4_timer_resources()
// ARM10C 20150321
// np: devtree에서 allnext로 순회 하면서 찾은 mct node의 주소, 0xf0006000
static void __init exynos4_timer_resources(struct device_node *np, void __iomem *base)
{
	int err;
	struct mct_clock_event_device *mevt = this_cpu_ptr(&percpu_mct_tick);
	// mevt: [pcp0] &percpu_mct_tick

	struct clk *mct_clk, *tick_clk;

	// np: devtree에서 allnext로 순회 하면서 찾은 mct node의 주소
	// of_clk_get_by_name(devtree에서 allnext로 순회 하면서 찾은 mct node의 주소, "fin_pll"): kmem_cache#29-oX (fin_pll)
	tick_clk = np ? of_clk_get_by_name(np, "fin_pll") :
				clk_get(NULL, "fin_pll");
	// tick_clk: kmem_cache#29-oX (fin_pll)

	// of_clk_get_by_name에서 한일:
	// mct node의 property "clock-names" 의 값을 찾아서 "fin_pll" 이 있는 위치를 찾고
	// 몇번째 값인지 index를 구함
	//
	// mct node 에서 "clocks" property의 이용하여 devtree의 값을 파싱하여 clkspec에 값을 가져옴
	// (&clkspec)->np: clock node의 주소
	// (&clkspec)->args_count: 1
	// (&clkspec)->args[0]: 1
	//
	// list of_clk_providers 에 등록된 정보들 중에 clkspec 와 매치되는 정보를 찾음
	// 이전에 만들어 놓은 clk_data의 clk_table 정보를 이용하여 clkspec에 있는 arg 값을 이용하여 clk을 찾음
	// tick_clk: kmem_cache#29-oX (fin_pll)

	// tick_clk: kmem_cache#29-oX (fin_pll), IS_ERR(kmem_cache#29-oX (fin_pll)): 0
	if (IS_ERR(tick_clk))
		panic("%s: unable to determine tick clock rate\n", __func__);

	// tick_clk: kmem_cache#29-oX (fin_pll)
	// clk_get_rate(kmem_cache#29-oX (fin_pll)): 24000000
	clk_rate = clk_get_rate(tick_clk);
	// clk_rate: 24000000

	// np: devtree에서 allnext로 순회 하면서 찾은 mct node의 주소
	// of_clk_get_by_name(devtree에서 allnext로 순회 하면서 찾은 mct node의 주소, "mct"):  kmem_cache#29-oX (mct)
	mct_clk = np ? of_clk_get_by_name(np, "mct") : clk_get(NULL, "mct");
	// mct_clk: kmem_cache#29-oX (mct)

	// of_clk_get_by_name에서 한일:
	// mct node의 property "clock-names" 의 값을 찾아서 "mct" 이 있는 위치를 찾고
	// 몇번째 값인지 index를 구함
	//
	// mct node 에서 "clocks" property의 이용하여 devtree의 값을 파싱하여 clkspec에 값을 가져옴
	// (&clkspec)->np: clock node의 주소
	// (&clkspec)->args_count: 1
	// (&clkspec)->args[0]: 315
	//
	// list of_clk_providers 에 등록된 정보들 중에 clkspec 와 매치되는 정보를 찾음
	// 이전에 만들어 놓은 clk_data의 clk_table 정보를 이용하여 clkspec에 있는 arg 값을 이용하여 clk을 찾음
	// mct_clk: kmem_cache#29-oX (mct)

	// mct_clk: kmem_cache#29-oX (mct), IS_ERR(kmem_cache#29-oX (mct)): 0
	if (IS_ERR(mct_clk))
		panic("%s: unable to retrieve mct clock instance\n", __func__);

	// mct_clk: kmem_cache#29-oX (mct)
	// clk_prepare_enable(kmem_cache#29-oX (mct)): 0
	clk_prepare_enable(mct_clk);

	// clk_prepare_enable에서 한일:
	// mct clock의 상위 clock 들의 ops->prepare 함수들을 수행.
	// mct clock의 상위 clock 들의 ops->enable 함수들을 수행.
	// sck_cpll -- Group1_p -- mout_aclk66 -- dout_aclk66 -- mct
	// sck_ppll -|
	// sck_mpll -|
	//
	// sck_cpll, mout_aclk66, dout_aclk66 의 주석을 만들지 않았기 때문에
	// 분석내용을 skip 하도록함

	// base: 0xf0006000
	reg_base = base;
	// reg_base: 0xf0006000

	// reg_base: 0xf0006000
	if (!reg_base)
		panic("%s: unable to ioremap mct address space\n", __func__);

	// mct_int_type: 0, MCT_INT_PPI: 1
	if (mct_int_type == MCT_INT_PPI) {

		err = request_percpu_irq(mct_irqs[MCT_L0_IRQ],
					 exynos4_mct_tick_isr, "MCT",
					 &percpu_mct_tick);
		WARN(err, "MCT: can't request IRQ %d (%d)\n",
		     mct_irqs[MCT_L0_IRQ], err);
	} else {
		// MCT_L0_IRQ: 4, mct_irqs[4]: 152, cpumask_of(0): &cpu_bit_bitmap[1][0]
		// irq_set_affinity(152, &cpu_bit_bitmap[1][0]): 0
		irq_set_affinity(mct_irqs[MCT_L0_IRQ], cpumask_of(0));

		// irq_set_affinity에서 한일:
		//
		// Interrupt pending register인 GICD_ITARGETSR38 값을 읽고
		// 그 값과 mask 값인 cpu_bit_bitmap[1][0] 을 or 연산한 값을 GICD_ITARGETSR38에
		// 다시 write함
		//
		// GICD_ITARGETSR38 값을 모르기 때문에 0x00000000 로
		// 읽히는 것으로 가정하고 GICD_ITARGETSR38에 0x00000001를 write 함
		// CPU interface 0에 interrupt가 발생을 나타냄
		//
		// (&(kmem_cache#28-oX (irq 152))->irq_data)->affinity->bits[0]: 1
		// (&(kmem_cache#28-oX (irq 152))->irq_data)->state_use_accessors: 0x11000
	}

	// register_cpu_notifier(&exynos4_mct_cpu_nb): 0
	err = register_cpu_notifier(&exynos4_mct_cpu_nb);
	// err: 0

	// register_cpu_notifier 에서 한일:
	// (&cpu_chain)->head: &exynos4_mct_cpu_nb 포인터 대입
	// (&exynos4_mct_cpu_nb)->next은 (&hrtimers_nb)->next로 대입

	// err: 0
	if (err)
		goto out_irq;

	/* Immediately configure the timer on the boot CPU */
	// &mevt->evt: [pcp0] &(&percpu_mct_tick)->evt
	exynos4_local_timer_setup(&mevt->evt);
  • called: start_kernel()->time_init()->clocksource_of_init()->init_func(np)
  • // np: devtree에서 allnext로 순회 하면서 찾은 mct node의 주소, MCT_INT_SPI: 0
  • ->init_func(np)->mct_init_spi()->mct_init_dt()
  • exynos4_timer_resources()
  • exynos4_local_timer_setup(&mevt->evt);

exynos_mct.c::exynos4_local_timer_setup()

  • called: start_kernel()->time_init()->clocksource_of_init()->init_func(np)
  • // np: devtree에서 allnext로 순회 하면서 찾은 mct node의 주소, MCT_INT_SPI: 0
  • ->init_func(np)->mct_init_spi()->mct_init_dt()
  • exynos4_timer_resources()
  • exynos4_local_timer_setup(&mevt->evt);
// ARM10C 20150404
// &mevt->evt: [pcp0] &(&percpu_mct_tick)->evt
static int exynos4_local_timer_setup(struct clock_event_device *evt)
{
	struct mct_clock_event_device *mevt;

	// smp_processor_id(): 0
	unsigned int cpu = smp_processor_id();
	// cpu: 0

	// evt: [pcp0] &(&percpu_mct_tick)->evt
	// container_of([pcp0] &(&percpu_mct_tick)->evt, struct mct_clock_event_device, evt): [pcp0] &percpu_mct_tick
	mevt = container_of(evt, struct mct_clock_event_device, evt);
	// mevt: [pcp0] &percpu_mct_tick

	// mevt->base: [pcp0] (&percpu_mct_tick)->base,
	// cpu: 0, EXYNOS4_MCT_L_BASE(0): 0x300
	mevt->base = EXYNOS4_MCT_L_BASE(cpu);
	// mevt->base: [pcp0] (&percpu_mct_tick)->base: 0x300

	// mevt->name: [pcp0] (&percpu_mct_tick)->name, cpu: 0
	sprintf(mevt->name, "mct_tick%d", cpu);
	// mevt->name: [pcp0] (&percpu_mct_tick)->name: "mct_tick0"

	// evt->name: [pcp0] (&(&percpu_mct_tick)->evt)->name,
	// mevt->name: [pcp0] (&percpu_mct_tick)->name: "mct_tick0"
	evt->name = mevt->name;
	// evt->name: [pcp0] (&(&percpu_mct_tick)->evt)->name: "mct_tick0"

	// evt->cpumask: [pcp0] (&(&percpu_mct_tick)->evt)->cpumask,
	// cpu: 0, cpumask_of(0): &cpu_bit_bitmap[1][0]
	evt->cpumask = cpumask_of(cpu);
	// evt->cpumask: [pcp0] (&(&percpu_mct_tick)->evt)->cpumask: &cpu_bit_bitmap[1][0]

	// evt->set_next_event: [pcp0] (&(&percpu_mct_tick)->evt)->set_next_event
	evt->set_next_event = exynos4_tick_set_next_event;
	// evt->set_next_event: [pcp0] (&(&percpu_mct_tick)->evt)->set_next_event: exynos4_tick_set_next_event

	// evt->set_mode: [pcp0] (&(&percpu_mct_tick)->evt)->set_mode
	evt->set_mode = exynos4_tick_set_mode;
	// evt->set_mode: [pcp0] (&(&percpu_mct_tick)->evt)->set_mode: exynos4_tick_set_mode

	// evt->features: [pcp0] (&(&percpu_mct_tick)->evt)->features,
	// CLOCK_EVT_FEAT_PERIODIC: 0x000001, CLOCK_EVT_FEAT_ONESHOT: 0x000002
	evt->features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT;
	// evt->features: [pcp0] (&(&percpu_mct_tick)->evt)->features: 0x3

	// evt->rating: [pcp0] (&(&percpu_mct_tick)->evt)->rating
	evt->rating = 450;
	// evt->rating: [pcp0] (&(&percpu_mct_tick)->evt)->rating: 450

	// evt: [pcp0] &(&percpu_mct_tick)->evt, clk_rate: 24000000, TICK_BASE_CNT: 1
	clockevents_config_and_register(evt, clk_rate / (TICK_BASE_CNT + 1),
					0xf, 0x7fffffff);

clockevents.c::clockevents_config_and_register()

// ARM10C 20150404
// evt: [pcp0] &(&percpu_mct_tick)->evt, 12000000, 0xf, 0x7fffffff
void clockevents_config_and_register(struct clock_event_device *dev,
				     u32 freq, unsigned long min_delta,
				     unsigned long max_delta)
{
	// dev->min_delta_ticks: [pcp0] (&(&percpu_mct_tick)->evt)->min_delta_ticks, min_delta: 0xf
	dev->min_delta_ticks = min_delta;
	// dev->min_delta_ticks: [pcp0] (&(&percpu_mct_tick)->evt)->min_delta_ticks: 0xf

	// dev->max_delta_ticks: [pcp0] (&(&percpu_mct_tick)->evt)->max_delta_ticks, max_delta: 0x7fffffff
	dev->max_delta_ticks = max_delta;
	// dev->max_delta_ticks: [pcp0] (&(&percpu_mct_tick)->evt)->max_delta_ticks: 0x7fffffff

	// dev: [pcp0] &(&percpu_mct_tick)->evt, freq: 12000000
	// clockevents_config(&(&percpu_mct_tick)->evt, 12000000)
	clockevents_config(dev, freq);

	// clockevents_config에서 한일:
	// [pcp0] (&(&percpu_mct_tick)->evt)->mult: 0x3126E98
	// [pcp0] (&(&percpu_mct_tick)->evt)->shift: 32
	// [pcp0] (&(&percpu_mct_tick)->evt)->min_delta_ns: 0x4E2
	// [pcp0] (&(&percpu_mct_tick)->evt)->max_delta_ns: 0x29AAAAA444

	// dev: [pcp0] &(&percpu_mct_tick)->evt
	clockevents_register_device(dev);
}
EXPORT_SYMBOL_GPL(clockevents_config_and_register);

clockevents.c::clockevents_register_device()

// ARM10C 20150411
// dev: [pcp0] &(&percpu_mct_tick)->evt
void clockevents_register_device(struct clock_event_device *dev)
{
	unsigned long flags;

	// dev->mode: [pcp0] (&(&percpu_mct_tick)->evt)->mode: 0, CLOCK_EVT_MODE_UNUSED: 0
	BUG_ON(dev->mode != CLOCK_EVT_MODE_UNUSED);

	// evt->cpumask: [pcp0] (&(&percpu_mct_tick)->evt)->cpumask: &cpu_bit_bitmap[1][0]
	if (!dev->cpumask) {
		WARN_ON(num_possible_cpus() > 1);
		dev->cpumask = cpumask_of(smp_processor_id());
	}

	raw_spin_lock_irqsave(&clockevents_lock, flags);

	// raw_spin_lock_irqsave에서 한일:
	// clockevents_lock를 사용하여 spin lock을 수행하고 cpsr을 flags에 저장

	// &dev->list: [pcp0] (&(&percpu_mct_tick)->evt)->list
	list_add(&dev->list, &clockevent_devices);

	// list_add에서 한일:
	// list clockevent_devices에 [pcp0] (&(&percpu_mct_tick)->evt)->list를 추가함

	// dev: [pcp0] &(&percpu_mct_tick)->evt
	tick_check_new_device(dev);
	clockevents_notify_released();

	raw_spin_unlock_irqrestore(&clockevents_lock, flags);
}
EXPORT_SYMBOL_GPL(clockevents_register_device);

tick-common.c:tick_check_new_device()

// ARM10C 20150411
// dev: [pcp0] &(&percpu_mct_tick)->evt
void tick_check_new_device(struct clock_event_device *newdev)
{
	struct clock_event_device *curdev;
	struct tick_device *td;
	int cpu;

	// smp_processor_id(): 0
	cpu = smp_processor_id();
	// cpu: 0

	// cpu: 0, newdev->cpumask: [pcp0] (&(&percpu_mct_tick)->evt)->cpumask: &cpu_bit_bitmap[1][0]
	// cpumask_test_cpu(0, &cpu_bit_bitmap[1][0]): 1
	if (!cpumask_test_cpu(cpu, newdev->cpumask))
		goto out_bc;

	// cpu: 0, per_cpu(tick_cpu_device, 0): [pcp0] tick_cpu_device
	td = &per_cpu(tick_cpu_device, cpu);
	// td: [pcp0] &tick_cpu_device

	// td->evtdev: [pcp0] (&tick_cpu_device)->evtdev
	curdev = td->evtdev;
	// curdev: [pcp0] (&tick_cpu_device)->evtdev

	/* cpu local device ? */
	// curdev: [pcp0] (&tick_cpu_device)->evtdev, newdev: [pcp0] &(&percpu_mct_tick)->evt, cpu: 0
	// tick_check_percpu([pcp0] (&tick_cpu_device)->evtdev, [pcp0] &(&percpu_mct_tick)->evt, 0): true
	if (!tick_check_percpu(curdev, newdev, cpu))
		goto out_bc;

	/* Preference decision */
	// curdev: [pcp0] (&tick_cpu_device)->evtdev, newdev: [pcp0] &(&percpu_mct_tick)->evt
	// tick_check_preferred([pcp0] (&tick_cpu_device)->evtdev, [pcp0] &(&percpu_mct_tick)->evt): 1
	if (!tick_check_preferred(curdev, newdev))
		goto out_bc;

	// newdev->owner: [pcp0] (&(&percpu_mct_tick)->evt)->owner,
	// try_module_get([pcp0] (&(&percpu_mct_tick)->evt)->owner): true
	if (!try_module_get(newdev->owner))
		return;

	/*
	 * Replace the eventually existing device by the new
	 * device. If the current device is the broadcast device, do
	 * not give it back to the clockevents layer !
	 */
	// curdev: [pcp0] (&tick_cpu_device)->evtdev: NULL
	// tick_is_broadcast_device([pcp0] (&tick_cpu_device)->evtdev): 0
	if (tick_is_broadcast_device(curdev)) {
		clockevents_shutdown(curdev);
		curdev = NULL;
	}

	// curdev: [pcp0] (&tick_cpu_device)->evtdev: NULL, newdev: [pcp0] &(&percpu_mct_tick)->evt
	// clockevents_exchange_device(NULL, [pcp0] &(&percpu_mct_tick)->evt)
	clockevents_exchange_device(curdev, newdev);

	// clockevents_exchange_device에서 한일:
	// timer control register L0_TCON 값을 읽어 timer start, timer interrupt 설정을
	// 동작하지 않도록 변경함
	// L0_TCON 값이 0 으로 가정하였으므로 timer는 동작하지 않은 상태임
	//
	// [pcp0] (&(&percpu_mct_tick)->evt)->mode: 1
	// [pcp0] (&(&percpu_mct_tick)->evt)->next_event.tv64: 0x7FFFFFFFFFFFFFFF

	// td: [pcp0] &tick_cpu_device, newdev: [pcp0] &(&percpu_mct_tick)->evt, cpu: 0, cpumask_of(0): &cpu_bit_bitmap[1][0]
	tick_setup_device(td, newdev, cpu, cpumask_of(cpu));

tick-common.c::tick_setup_device()

// ARM10C 20150418
// td: [pcp0] &tick_cpu_device, newdev: [pcp0] &(&percpu_mct_tick)->evt, cpu: 0, cpumask_of(0): &cpu_bit_bitmap[1][0]
static void tick_setup_device(struct tick_device *td,
			      struct clock_event_device *newdev, int cpu,
			      const struct cpumask *cpumask)
{
	ktime_t next_event;
	void (*handler)(struct clock_event_device *) = NULL;
	// handler: NULL

	/*
	 * First device setup ?
	 */
	// td->evtdev: [pcp0] (&tick_cpu_device)->evtdev: NULL
	if (!td->evtdev) {
		/*
		 * If no cpu took the do_timer update, assign it to
		 * this cpu:
		 */
		// tick_do_timer_cpu: -2, TICK_DO_TIMER_BOOT: -2
		if (tick_do_timer_cpu == TICK_DO_TIMER_BOOT) {
			// cpu: 0, tick_nohz_full_cpu(0): false
			if (!tick_nohz_full_cpu(cpu))
				// tick_do_timer_cpu: -2, cpu: 0
				tick_do_timer_cpu = cpu;
				// tick_do_timer_cpu: 0
			else
				tick_do_timer_cpu = TICK_DO_TIMER_NONE;

			// ktime_get(): (ktime_t) { .tv64 = 0}
			tick_next_period = ktime_get();
			// tick_next_period.tv64: 0

			// NSEC_PER_SEC: 1000000000L, HZ: 100
			// ktime_set(0, 10000000): (ktime_t) { .tv64 = 10000000}
			tick_period = ktime_set(0, NSEC_PER_SEC / HZ);
			// tick_period.tv64: 10000000
		}

		/*
		 * Startup in periodic mode first.
		 */
		// td->mode: [pcp0] (&tick_cpu_device)->mode, TICKDEV_MODE_PERIODIC: 0
		td->mode = TICKDEV_MODE_PERIODIC;
		// td->mode: [pcp0] (&tick_cpu_device)->mode: 0
	} else {
		handler = td->evtdev->event_handler;
		next_event = td->evtdev->next_event;
		td->evtdev->event_handler = clockevents_handle_noop;
	}

	// td->evtdev: [pcp0] (&tick_cpu_device)->evtdev: NULL, newdev: [pcp0] &(&percpu_mct_tick)->evt
	td->evtdev = newdev;
	// td->evtdev: [pcp0] (&tick_cpu_device)->evtdev: [pcp0] &(&percpu_mct_tick)->evt

	/*
	 * When the device is not per cpu, pin the interrupt to the
	 * current cpu:
	 */
	// newdev->cpumask: [pcp0] (&(&percpu_mct_tick)->evt)->cpumask: &cpu_bit_bitmap[1][0],
	// cpumask: &cpu_bit_bitmap[1][0]
	// cpumask_equal(&cpu_bit_bitmap[1][0], &cpu_bit_bitmap[1][0]): 1
	if (!cpumask_equal(newdev->cpumask, cpumask))
		irq_set_affinity(newdev->irq, cpumask);

	/*
	 * When global broadcasting is active, check if the current
	 * device is registered as a placeholder for broadcast mode.
	 * This allows us to handle this x86 misfeature in a generic
	 * way. This function also returns !=0 when we keep the
	 * current active broadcast state for this CPU.
	 */
	// newdev: [pcp0] &(&percpu_mct_tick)->evt, cpu: 0
	// tick_device_uses_broadcast([pcp0] &(&percpu_mct_tick)->evt, 0): 0
	if (tick_device_uses_broadcast(newdev, cpu))
		return;

	// td->mode: [pcp0] (&tick_cpu_device)->mode: 0, TICKDEV_MODE_PERIODIC: 0
	if (td->mode == TICKDEV_MODE_PERIODIC)
		// newdev: [pcp0] &(&percpu_mct_tick)->evt
		tick_setup_periodic(newdev, 0);
	else
		tick_setup_oneshot(newdev, handler, next_event);
}
  • call: tick_setup_periodic()

tick-common.c:tick_setup_periodic()

  • called: tick_setup_periodic()
// ARM10C 20150418
// newdev: [pcp0] &(&percpu_mct_tick)->evt, 0
void tick_setup_periodic(struct clock_event_device *dev, int broadcast)
{
	// dev: [pcp0] &(&percpu_mct_tick)->evt, broadcast: 0
	tick_set_periodic_handler(dev, broadcast);

	// tick_set_periodic_handler에서 한일:
	// [pcp0] (&(&percpu_mct_tick)->evt)->event_handler: tick_handle_periodic

	/* Broadcast setup ? */
	// dev: [pcp0] &(&percpu_mct_tick)->evt,
	// tick_device_is_functional([pcp0] &(&percpu_mct_tick)->evt): 1
	if (!tick_device_is_functional(dev))
		return;

// 2015/04/18 종료

log

  • 1st log
   cbe0317..46c6178  master     -> origin/master
Updating cbe0317..46c6178
Fast-forward
arch/arm/kernel/vmlinux.lds.S       |  1 +
drivers/clocksource/exynos_mct.c    | 48 +++++++++++++++++++++++++++++++++++++++++++-----
include/linux/clockchips.h          |  4 ++++
include/linux/clocksource.h         |  2 ++
include/linux/compiler.h            |  1 +
include/linux/cpumask.h             |  1 +
include/linux/jiffies.h             |  1 +
include/linux/ktime.h               |  2 ++
include/linux/percpu-defs.h         |  4 ++++
include/linux/seqlock.h             | 25 +++++++++++++++++++++++--
include/linux/tick.h                |  1 +
include/linux/time.h                |  1 +
include/linux/timekeeper_internal.h |  1 +
kernel/time/clockevents.c           | 32 +++++++++++++++++++++++++++++++-
kernel/time/jiffies.c               |  2 ++
kernel/time/tick-common.c           | 23 +++++++++++++++++++++++
kernel/time/tick-internal.h         |  2 ++
kernel/time/timekeeping.c           | 25 +++++++++++++++++++++++++
kernel/timer.c                      |  1 +
19 files changed, 169 insertions(+), 8 deletions(-)
  • 2nd log
   46c6178..8299c20  master     -> origin/master
Updating 46c6178..8299c20
Fast-forward
include/asm-generic/param.h  |  1 +
include/linux/bitmap.h       |  7 ++++++
include/linux/clockchips.h   |  5 ++++
include/linux/cpumask.h      | 11 +++++++++
include/linux/ktime.h        |  6 +++++
include/linux/seqlock.h      | 29 +++++++++++++++--------
include/linux/spinlock.h     |  1 +
include/linux/tick.h         |  4 ++++
include/linux/time.h         |  1 +
kernel/time/tick-broadcast.c | 55 ++++++++++++++++++++++++++++++++++++++++++--
kernel/time/tick-common.c    | 32 ++++++++++++++++++++++++++
kernel/time/tick-internal.h  | 10 ++++++--
kernel/time/tick-oneshot.c   |  1 +
kernel/time/timekeeping.c    | 26 +++++++++++++++++----
14 files changed, 170 insertions(+), 19 deletions(-)