usb: dwc3: add rockchip specific glue layer
[firefly-linux-kernel-4.4.55.git] / drivers / clocksource / arm_arch_timer.c
index a2b25418978244d1ae129cf74f031020951f35d4..c64d543d64bf69576d9d75ffc54839439c70ea9b 100644 (file)
 #include <linux/device.h>
 #include <linux/smp.h>
 #include <linux/cpu.h>
+#include <linux/cpu_pm.h>
 #include <linux/clockchips.h>
+#include <linux/clocksource.h>
 #include <linux/interrupt.h>
 #include <linux/of_irq.h>
+#include <linux/of_address.h>
 #include <linux/io.h>
+#include <linux/slab.h>
+#include <linux/sched_clock.h>
+#include <linux/acpi.h>
 
 #include <asm/arch_timer.h>
 #include <asm/virt.h>
 
 #include <clocksource/arm_arch_timer.h>
 
+#define CNTTIDR                0x08
+#define CNTTIDR_VIRT(n)        (BIT(1) << ((n) * 4))
+
+#define CNTVCT_LO      0x08
+#define CNTVCT_HI      0x0c
+#define CNTFRQ         0x10
+#define CNTP_TVAL      0x28
+#define CNTP_CTL       0x2c
+#define CNTV_TVAL      0x38
+#define CNTV_CTL       0x3c
+
+#define ARCH_CP15_TIMER        BIT(0)
+#define ARCH_MEM_TIMER BIT(1)
+static unsigned arch_timers_present __initdata;
+
+static void __iomem *arch_counter_base;
+
+struct arch_timer {
+       void __iomem *base;
+       struct clock_event_device evt;
+};
+
+#define to_arch_timer(e) container_of(e, struct arch_timer, evt)
+
 static u32 arch_timer_rate;
 
 enum ppi_nr {
@@ -38,19 +68,84 @@ static int arch_timer_ppi[MAX_TIMER_PPI];
 static struct clock_event_device __percpu *arch_timer_evt;
 
 static bool arch_timer_use_virtual = true;
+static bool arch_timer_c3stop;
+static bool arch_timer_mem_use_virtual;
 
 /*
  * Architected system timer support.
  */
 
-static inline irqreturn_t timer_handler(const int access,
+static __always_inline
+void arch_timer_reg_write(int access, enum arch_timer_reg reg, u32 val,
+                         struct clock_event_device *clk)
+{
+       if (access == ARCH_TIMER_MEM_PHYS_ACCESS) {
+               struct arch_timer *timer = to_arch_timer(clk);
+               switch (reg) {
+               case ARCH_TIMER_REG_CTRL:
+                       writel_relaxed(val, timer->base + CNTP_CTL);
+                       break;
+               case ARCH_TIMER_REG_TVAL:
+                       writel_relaxed(val, timer->base + CNTP_TVAL);
+                       break;
+               }
+       } else if (access == ARCH_TIMER_MEM_VIRT_ACCESS) {
+               struct arch_timer *timer = to_arch_timer(clk);
+               switch (reg) {
+               case ARCH_TIMER_REG_CTRL:
+                       writel_relaxed(val, timer->base + CNTV_CTL);
+                       break;
+               case ARCH_TIMER_REG_TVAL:
+                       writel_relaxed(val, timer->base + CNTV_TVAL);
+                       break;
+               }
+       } else {
+               arch_timer_reg_write_cp15(access, reg, val);
+       }
+}
+
+static __always_inline
+u32 arch_timer_reg_read(int access, enum arch_timer_reg reg,
+                       struct clock_event_device *clk)
+{
+       u32 val;
+
+       if (access == ARCH_TIMER_MEM_PHYS_ACCESS) {
+               struct arch_timer *timer = to_arch_timer(clk);
+               switch (reg) {
+               case ARCH_TIMER_REG_CTRL:
+                       val = readl_relaxed(timer->base + CNTP_CTL);
+                       break;
+               case ARCH_TIMER_REG_TVAL:
+                       val = readl_relaxed(timer->base + CNTP_TVAL);
+                       break;
+               }
+       } else if (access == ARCH_TIMER_MEM_VIRT_ACCESS) {
+               struct arch_timer *timer = to_arch_timer(clk);
+               switch (reg) {
+               case ARCH_TIMER_REG_CTRL:
+                       val = readl_relaxed(timer->base + CNTV_CTL);
+                       break;
+               case ARCH_TIMER_REG_TVAL:
+                       val = readl_relaxed(timer->base + CNTV_TVAL);
+                       break;
+               }
+       } else {
+               val = arch_timer_reg_read_cp15(access, reg);
+       }
+
+       return val;
+}
+
+static __always_inline irqreturn_t timer_handler(const int access,
                                        struct clock_event_device *evt)
 {
        unsigned long ctrl;
-       ctrl = arch_timer_reg_read(access, ARCH_TIMER_REG_CTRL);
+
+       ctrl = arch_timer_reg_read(access, ARCH_TIMER_REG_CTRL, evt);
        if (ctrl & ARCH_TIMER_CTRL_IT_STAT) {
                ctrl |= ARCH_TIMER_CTRL_IT_MASK;
-               arch_timer_reg_write(access, ARCH_TIMER_REG_CTRL, ctrl);
+               arch_timer_reg_write(access, ARCH_TIMER_REG_CTRL, ctrl, evt);
                evt->event_handler(evt);
                return IRQ_HANDLED;
        }
@@ -72,78 +167,180 @@ static irqreturn_t arch_timer_handler_phys(int irq, void *dev_id)
        return timer_handler(ARCH_TIMER_PHYS_ACCESS, evt);
 }
 
-static inline void timer_set_mode(const int access, int mode)
+static irqreturn_t arch_timer_handler_phys_mem(int irq, void *dev_id)
+{
+       struct clock_event_device *evt = dev_id;
+
+       return timer_handler(ARCH_TIMER_MEM_PHYS_ACCESS, evt);
+}
+
+static irqreturn_t arch_timer_handler_virt_mem(int irq, void *dev_id)
+{
+       struct clock_event_device *evt = dev_id;
+
+       return timer_handler(ARCH_TIMER_MEM_VIRT_ACCESS, evt);
+}
+
+static __always_inline int timer_shutdown(const int access,
+                                         struct clock_event_device *clk)
 {
        unsigned long ctrl;
-       switch (mode) {
-       case CLOCK_EVT_MODE_UNUSED:
-       case CLOCK_EVT_MODE_SHUTDOWN:
-               ctrl = arch_timer_reg_read(access, ARCH_TIMER_REG_CTRL);
-               ctrl &= ~ARCH_TIMER_CTRL_ENABLE;
-               arch_timer_reg_write(access, ARCH_TIMER_REG_CTRL, ctrl);
-               break;
-       default:
-               break;
-       }
+
+       ctrl = arch_timer_reg_read(access, ARCH_TIMER_REG_CTRL, clk);
+       ctrl &= ~ARCH_TIMER_CTRL_ENABLE;
+       arch_timer_reg_write(access, ARCH_TIMER_REG_CTRL, ctrl, clk);
+
+       return 0;
+}
+
+static int arch_timer_shutdown_virt(struct clock_event_device *clk)
+{
+       return timer_shutdown(ARCH_TIMER_VIRT_ACCESS, clk);
 }
 
-static void arch_timer_set_mode_virt(enum clock_event_mode mode,
-                                    struct clock_event_device *clk)
+static int arch_timer_shutdown_phys(struct clock_event_device *clk)
 {
-       timer_set_mode(ARCH_TIMER_VIRT_ACCESS, mode);
+       return timer_shutdown(ARCH_TIMER_PHYS_ACCESS, clk);
 }
 
-static void arch_timer_set_mode_phys(enum clock_event_mode mode,
-                                    struct clock_event_device *clk)
+static int arch_timer_shutdown_virt_mem(struct clock_event_device *clk)
 {
-       timer_set_mode(ARCH_TIMER_PHYS_ACCESS, mode);
+       return timer_shutdown(ARCH_TIMER_MEM_VIRT_ACCESS, clk);
 }
 
-static inline void set_next_event(const int access, unsigned long evt)
+static int arch_timer_shutdown_phys_mem(struct clock_event_device *clk)
+{
+       return timer_shutdown(ARCH_TIMER_MEM_PHYS_ACCESS, clk);
+}
+
+static __always_inline void set_next_event(const int access, unsigned long evt,
+                                          struct clock_event_device *clk)
 {
        unsigned long ctrl;
-       ctrl = arch_timer_reg_read(access, ARCH_TIMER_REG_CTRL);
+       ctrl = arch_timer_reg_read(access, ARCH_TIMER_REG_CTRL, clk);
        ctrl |= ARCH_TIMER_CTRL_ENABLE;
        ctrl &= ~ARCH_TIMER_CTRL_IT_MASK;
-       arch_timer_reg_write(access, ARCH_TIMER_REG_TVAL, evt);
-       arch_timer_reg_write(access, ARCH_TIMER_REG_CTRL, ctrl);
+       arch_timer_reg_write(access, ARCH_TIMER_REG_TVAL, evt, clk);
+       arch_timer_reg_write(access, ARCH_TIMER_REG_CTRL, ctrl, clk);
 }
 
 static int arch_timer_set_next_event_virt(unsigned long evt,
-                                         struct clock_event_device *unused)
+                                         struct clock_event_device *clk)
 {
-       set_next_event(ARCH_TIMER_VIRT_ACCESS, evt);
+       set_next_event(ARCH_TIMER_VIRT_ACCESS, evt, clk);
        return 0;
 }
 
 static int arch_timer_set_next_event_phys(unsigned long evt,
-                                         struct clock_event_device *unused)
+                                         struct clock_event_device *clk)
 {
-       set_next_event(ARCH_TIMER_PHYS_ACCESS, evt);
+       set_next_event(ARCH_TIMER_PHYS_ACCESS, evt, clk);
        return 0;
 }
 
-static int __cpuinit arch_timer_setup(struct clock_event_device *clk)
+static int arch_timer_set_next_event_virt_mem(unsigned long evt,
+                                             struct clock_event_device *clk)
 {
-       clk->features = CLOCK_EVT_FEAT_ONESHOT | CLOCK_EVT_FEAT_C3STOP;
-       clk->name = "arch_sys_timer";
-       clk->rating = 450;
-       if (arch_timer_use_virtual) {
-               clk->irq = arch_timer_ppi[VIRT_PPI];
-               clk->set_mode = arch_timer_set_mode_virt;
-               clk->set_next_event = arch_timer_set_next_event_virt;
+       set_next_event(ARCH_TIMER_MEM_VIRT_ACCESS, evt, clk);
+       return 0;
+}
+
+static int arch_timer_set_next_event_phys_mem(unsigned long evt,
+                                             struct clock_event_device *clk)
+{
+       set_next_event(ARCH_TIMER_MEM_PHYS_ACCESS, evt, clk);
+       return 0;
+}
+
+static void __arch_timer_setup(unsigned type,
+                              struct clock_event_device *clk)
+{
+       clk->features = CLOCK_EVT_FEAT_ONESHOT;
+
+       if (type == ARCH_CP15_TIMER) {
+               if (arch_timer_c3stop)
+                       clk->features |= CLOCK_EVT_FEAT_C3STOP;
+               clk->name = "arch_sys_timer";
+               clk->rating = 450;
+               clk->cpumask = cpumask_of(smp_processor_id());
+               if (arch_timer_use_virtual) {
+                       clk->irq = arch_timer_ppi[VIRT_PPI];
+                       clk->set_state_shutdown = arch_timer_shutdown_virt;
+                       clk->set_next_event = arch_timer_set_next_event_virt;
+               } else {
+                       clk->irq = arch_timer_ppi[PHYS_SECURE_PPI];
+                       clk->set_state_shutdown = arch_timer_shutdown_phys;
+                       clk->set_next_event = arch_timer_set_next_event_phys;
+               }
        } else {
-               clk->irq = arch_timer_ppi[PHYS_SECURE_PPI];
-               clk->set_mode = arch_timer_set_mode_phys;
-               clk->set_next_event = arch_timer_set_next_event_phys;
+               clk->features |= CLOCK_EVT_FEAT_DYNIRQ;
+               clk->name = "arch_mem_timer";
+               clk->rating = 400;
+               clk->cpumask = cpu_all_mask;
+               if (arch_timer_mem_use_virtual) {
+                       clk->set_state_shutdown = arch_timer_shutdown_virt_mem;
+                       clk->set_next_event =
+                               arch_timer_set_next_event_virt_mem;
+               } else {
+                       clk->set_state_shutdown = arch_timer_shutdown_phys_mem;
+                       clk->set_next_event =
+                               arch_timer_set_next_event_phys_mem;
+               }
        }
 
-       clk->cpumask = cpumask_of(smp_processor_id());
+       clk->set_state_shutdown(clk);
+
+       clockevents_config_and_register(clk, arch_timer_rate, 0xf, 0x7fffffff);
+}
+
+static void arch_timer_evtstrm_enable(int divider)
+{
+       u32 cntkctl = arch_timer_get_cntkctl();
+
+       cntkctl &= ~ARCH_TIMER_EVT_TRIGGER_MASK;
+       /* Set the divider and enable virtual event stream */
+       cntkctl |= (divider << ARCH_TIMER_EVT_TRIGGER_SHIFT)
+                       | ARCH_TIMER_VIRT_EVT_EN;
+       arch_timer_set_cntkctl(cntkctl);
+       elf_hwcap |= HWCAP_EVTSTRM;
+#ifdef CONFIG_COMPAT
+       compat_elf_hwcap |= COMPAT_HWCAP_EVTSTRM;
+#endif
+}
+
+static void arch_timer_configure_evtstream(void)
+{
+       int evt_stream_div, pos;
+
+       /* Find the closest power of two to the divisor */
+       evt_stream_div = arch_timer_rate / ARCH_TIMER_EVT_STREAM_FREQ;
+       pos = fls(evt_stream_div);
+       if (pos > 1 && !(evt_stream_div & (1 << (pos - 2))))
+               pos--;
+       /* enable event stream */
+       arch_timer_evtstrm_enable(min(pos, 15));
+}
+
+static void arch_counter_set_user_access(void)
+{
+       u32 cntkctl = arch_timer_get_cntkctl();
+
+       /* Disable user access to the timers and the physical counter */
+       /* Also disable virtual event stream */
+       cntkctl &= ~(ARCH_TIMER_USR_PT_ACCESS_EN
+                       | ARCH_TIMER_USR_VT_ACCESS_EN
+                       | ARCH_TIMER_VIRT_EVT_EN
+                       | ARCH_TIMER_USR_PCT_ACCESS_EN);
+
+       /* Enable user access to the virtual counter */
+       cntkctl |= ARCH_TIMER_USR_VCT_ACCESS_EN;
 
-       clk->set_mode(CLOCK_EVT_MODE_SHUTDOWN, NULL);
+       arch_timer_set_cntkctl(cntkctl);
+}
 
-       clockevents_config_and_register(clk, arch_timer_rate,
-                                       0xf, 0x7fffffff);
+static int arch_timer_setup(struct clock_event_device *clk)
+{
+       __arch_timer_setup(ARCH_CP15_TIMER, clk);
 
        if (arch_timer_use_virtual)
                enable_percpu_irq(arch_timer_ppi[VIRT_PPI], 0);
@@ -154,31 +351,51 @@ static int __cpuinit arch_timer_setup(struct clock_event_device *clk)
        }
 
        arch_counter_set_user_access();
+       if (IS_ENABLED(CONFIG_ARM_ARCH_TIMER_EVTSTREAM))
+               arch_timer_configure_evtstream();
 
        return 0;
 }
 
-static int arch_timer_available(void)
+static void
+arch_timer_detect_rate(void __iomem *cntbase, struct device_node *np)
 {
-       u32 freq;
-
-       if (arch_timer_rate == 0) {
-               freq = arch_timer_get_cntfrq();
-
-               /* Check the timer frequency. */
-               if (freq == 0) {
-                       pr_warn("Architected timer frequency not available\n");
-                       return -EINVAL;
-               }
+       /* Who has more than one independent system counter? */
+       if (arch_timer_rate)
+               return;
 
-               arch_timer_rate = freq;
+       /*
+        * Try to determine the frequency from the device tree or CNTFRQ,
+        * if ACPI is enabled, get the frequency from CNTFRQ ONLY.
+        */
+       if (!acpi_disabled ||
+           of_property_read_u32(np, "clock-frequency", &arch_timer_rate)) {
+               if (cntbase)
+                       arch_timer_rate = readl_relaxed(cntbase + CNTFRQ);
+               else
+                       arch_timer_rate = arch_timer_get_cntfrq();
        }
 
-       pr_info_once("Architected local timer running at %lu.%02luMHz (%s).\n",
+       /* Check the timer frequency. */
+       if (arch_timer_rate == 0)
+               pr_warn("Architected timer frequency not available\n");
+}
+
+static void arch_timer_banner(unsigned type)
+{
+       pr_info("Architected %s%s%s timer(s) running at %lu.%02luMHz (%s%s%s).\n",
+                    type & ARCH_CP15_TIMER ? "cp15" : "",
+                    type == (ARCH_CP15_TIMER | ARCH_MEM_TIMER) ?  " and " : "",
+                    type & ARCH_MEM_TIMER ? "mmio" : "",
                     (unsigned long)arch_timer_rate / 1000000,
                     (unsigned long)(arch_timer_rate / 10000) % 100,
-                    arch_timer_use_virtual ? "virt" : "phys");
-       return 0;
+                    type & ARCH_CP15_TIMER ?
+                       arch_timer_use_virtual ? "virt" : "phys" :
+                       "",
+                    type == (ARCH_CP15_TIMER | ARCH_MEM_TIMER) ?  "/" : "",
+                    type & ARCH_MEM_TIMER ?
+                       arch_timer_mem_use_virtual ? "virt" : "phys" :
+                       "");
 }
 
 u32 arch_timer_get_rate(void)
@@ -186,18 +403,26 @@ u32 arch_timer_get_rate(void)
        return arch_timer_rate;
 }
 
-/*
- * Some external users of arch_timer_read_counter (e.g. sched_clock) may try to
- * call it before it has been initialised. Rather than incur a performance
- * penalty checking for initialisation, provide a default implementation that
- * won't lead to time appearing to jump backwards.
- */
-static u64 arch_timer_read_zero(void)
+static u64 arch_counter_get_cntvct_mem(void)
 {
-       return 0;
+       u32 vct_lo, vct_hi, tmp_hi;
+
+       do {
+               vct_hi = readl_relaxed(arch_counter_base + CNTVCT_HI);
+               vct_lo = readl_relaxed(arch_counter_base + CNTVCT_LO);
+               tmp_hi = readl_relaxed(arch_counter_base + CNTVCT_HI);
+       } while (vct_hi != tmp_hi);
+
+       return ((u64) vct_hi << 32) | vct_lo;
 }
 
-u64 (*arch_timer_read_counter)(void) = arch_timer_read_zero;
+/*
+ * Default to cp15 based access because arm64 uses this function for
+ * sched_clock() before DT is probed and the cp15 method is guaranteed
+ * to exist on arm64. arm doesn't use this before DT is probed so even
+ * if we don't have the cp15 accessors we won't have a problem.
+ */
+u64 (*arch_timer_read_counter)(void) = arch_counter_get_cntvct;
 
 static cycle_t arch_counter_read(struct clocksource *cs)
 {
@@ -214,7 +439,7 @@ static struct clocksource clocksource_counter = {
        .rating = 400,
        .read   = arch_counter_read,
        .mask   = CLOCKSOURCE_MASK(56),
-       .flags  = CLOCK_SOURCE_IS_CONTINUOUS,
+       .flags  = CLOCK_SOURCE_IS_CONTINUOUS | CLOCK_SOURCE_SUSPEND_NONSTOP,
 };
 
 static struct cyclecounter cyclecounter = {
@@ -229,7 +454,38 @@ struct timecounter *arch_timer_get_timecounter(void)
        return &timecounter;
 }
 
-static void __cpuinit arch_timer_stop(struct clock_event_device *clk)
+static void __init arch_counter_register(unsigned type)
+{
+       u64 start_count;
+
+       /* Register the CP15 based counter if we have one */
+       if (type & ARCH_CP15_TIMER) {
+               if (IS_ENABLED(CONFIG_ARM64) || arch_timer_use_virtual)
+                       arch_timer_read_counter = arch_counter_get_cntvct;
+               else
+                       arch_timer_read_counter = arch_counter_get_cntpct;
+       } else {
+               arch_timer_read_counter = arch_counter_get_cntvct_mem;
+
+               /* If the clocksource name is "arch_sys_counter" the
+                * VDSO will attempt to read the CP15-based counter.
+                * Ensure this does not happen when CP15-based
+                * counter is not available.
+                */
+               clocksource_counter.name = "arch_mem_counter";
+       }
+
+       start_count = arch_timer_read_counter();
+       clocksource_register_hz(&clocksource_counter, arch_timer_rate);
+       cyclecounter.mult = clocksource_counter.mult;
+       cyclecounter.shift = clocksource_counter.shift;
+       timecounter_init(&timecounter, &cyclecounter, start_count);
+
+       /* 56 bits minimum, so we assume worst case rollover */
+       sched_clock_register(arch_timer_read_counter, 56, arch_timer_rate);
+}
+
+static void arch_timer_stop(struct clock_event_device *clk)
 {
        pr_debug("arch_timer_teardown disable IRQ%d cpu #%d\n",
                 clk->irq, smp_processor_id());
@@ -242,10 +498,10 @@ static void __cpuinit arch_timer_stop(struct clock_event_device *clk)
                        disable_percpu_irq(arch_timer_ppi[PHYS_NONSECURE_PPI]);
        }
 
-       clk->set_mode(CLOCK_EVT_MODE_UNUSED, clk);
+       clk->set_state_shutdown(clk);
 }
 
-static int __cpuinit arch_timer_cpu_notify(struct notifier_block *self,
+static int arch_timer_cpu_notify(struct notifier_block *self,
                                           unsigned long action, void *hcpu)
 {
        /*
@@ -264,31 +520,48 @@ static int __cpuinit arch_timer_cpu_notify(struct notifier_block *self,
        return NOTIFY_OK;
 }
 
-static struct notifier_block arch_timer_cpu_nb __cpuinitdata = {
+static struct notifier_block arch_timer_cpu_nb = {
        .notifier_call = arch_timer_cpu_notify,
 };
 
+#ifdef CONFIG_CPU_PM
+static unsigned int saved_cntkctl;
+static int arch_timer_cpu_pm_notify(struct notifier_block *self,
+                                   unsigned long action, void *hcpu)
+{
+       if (action == CPU_PM_ENTER)
+               saved_cntkctl = arch_timer_get_cntkctl();
+       else if (action == CPU_PM_ENTER_FAILED || action == CPU_PM_EXIT)
+               arch_timer_set_cntkctl(saved_cntkctl);
+       return NOTIFY_OK;
+}
+
+static struct notifier_block arch_timer_cpu_pm_notifier = {
+       .notifier_call = arch_timer_cpu_pm_notify,
+};
+
+static int __init arch_timer_cpu_pm_init(void)
+{
+       return cpu_pm_register_notifier(&arch_timer_cpu_pm_notifier);
+}
+#else
+static int __init arch_timer_cpu_pm_init(void)
+{
+       return 0;
+}
+#endif
+
 static int __init arch_timer_register(void)
 {
        int err;
        int ppi;
 
-       err = arch_timer_available();
-       if (err)
-               goto out;
-
        arch_timer_evt = alloc_percpu(struct clock_event_device);
        if (!arch_timer_evt) {
                err = -ENOMEM;
                goto out;
        }
 
-       clocksource_register_hz(&clocksource_counter, arch_timer_rate);
-       cyclecounter.mult = clocksource_counter.mult;
-       cyclecounter.shift = clocksource_counter.shift;
-       timecounter_init(&timecounter, &cyclecounter,
-                        arch_counter_get_cntpct());
-
        if (arch_timer_use_virtual) {
                ppi = arch_timer_ppi[VIRT_PPI];
                err = request_percpu_irq(ppi, arch_timer_handler_virt,
@@ -317,11 +590,17 @@ static int __init arch_timer_register(void)
        if (err)
                goto out_free_irq;
 
+       err = arch_timer_cpu_pm_init();
+       if (err)
+               goto out_unreg_notify;
+
        /* Immediately configure the timer on the boot CPU */
        arch_timer_setup(this_cpu_ptr(arch_timer_evt));
 
        return 0;
 
+out_unreg_notify:
+       unregister_cpu_notifier(&arch_timer_cpu_nb);
 out_free_irq:
        if (arch_timer_use_virtual)
                free_percpu_irq(arch_timer_ppi[VIRT_PPI], arch_timer_evt);
@@ -339,25 +618,78 @@ out:
        return err;
 }
 
-static void __init arch_timer_init(struct device_node *np)
+static int __init arch_timer_mem_register(void __iomem *base, unsigned int irq)
 {
-       u32 freq;
-       int i;
+       int ret;
+       irq_handler_t func;
+       struct arch_timer *t;
 
-       if (arch_timer_get_rate()) {
-               pr_warn("arch_timer: multiple nodes in dt, skipping\n");
-               return;
+       t = kzalloc(sizeof(*t), GFP_KERNEL);
+       if (!t)
+               return -ENOMEM;
+
+       t->base = base;
+       t->evt.irq = irq;
+       __arch_timer_setup(ARCH_MEM_TIMER, &t->evt);
+
+       if (arch_timer_mem_use_virtual)
+               func = arch_timer_handler_virt_mem;
+       else
+               func = arch_timer_handler_phys_mem;
+
+       ret = request_irq(irq, func, IRQF_TIMER, "arch_mem_timer", &t->evt);
+       if (ret) {
+               pr_err("arch_timer: Failed to request mem timer irq\n");
+               kfree(t);
        }
 
-       /* Try to determine the frequency from the device tree or CNTFRQ */
-       if (!of_property_read_u32(np, "clock-frequency", &freq))
-               arch_timer_rate = freq;
+       return ret;
+}
 
-       for (i = PHYS_SECURE_PPI; i < MAX_TIMER_PPI; i++)
-               arch_timer_ppi[i] = irq_of_parse_and_map(np, i);
+static const struct of_device_id arch_timer_of_match[] __initconst = {
+       { .compatible   = "arm,armv7-timer",    },
+       { .compatible   = "arm,armv8-timer",    },
+       {},
+};
+
+static const struct of_device_id arch_timer_mem_of_match[] __initconst = {
+       { .compatible   = "arm,armv7-timer-mem", },
+       {},
+};
 
-       of_node_put(np);
+static bool __init
+arch_timer_needs_probing(int type, const struct of_device_id *matches)
+{
+       struct device_node *dn;
+       bool needs_probing = false;
+
+       dn = of_find_matching_node(NULL, matches);
+       if (dn && of_device_is_available(dn) && !(arch_timers_present & type))
+               needs_probing = true;
+       of_node_put(dn);
+
+       return needs_probing;
+}
+
+static void __init arch_timer_common_init(void)
+{
+       unsigned mask = ARCH_CP15_TIMER | ARCH_MEM_TIMER;
+
+       /* Wait until both nodes are probed if we have two timers */
+       if ((arch_timers_present & mask) != mask) {
+               if (arch_timer_needs_probing(ARCH_MEM_TIMER, arch_timer_mem_of_match))
+                       return;
+               if (arch_timer_needs_probing(ARCH_CP15_TIMER, arch_timer_of_match))
+                       return;
+       }
+
+       arch_timer_banner(arch_timers_present);
+       arch_counter_register(arch_timers_present);
+       arch_timer_arch_init();
+}
 
+static void __init arch_timer_init(void)
+{
        /*
         * If HYP mode is available, we know that the physical timer
         * has been configured to be accessible from PL1. Use it, so
@@ -376,13 +708,161 @@ static void __init arch_timer_init(struct device_node *np)
                }
        }
 
-       if (arch_timer_use_virtual)
-               arch_timer_read_counter = arch_counter_get_cntvct;
+       arch_timer_register();
+       arch_timer_common_init();
+}
+
+static void __init arch_timer_of_init(struct device_node *np)
+{
+       int i;
+
+       if (arch_timers_present & ARCH_CP15_TIMER) {
+               pr_warn("arch_timer: multiple nodes in dt, skipping\n");
+               return;
+       }
+
+       arch_timers_present |= ARCH_CP15_TIMER;
+       for (i = PHYS_SECURE_PPI; i < MAX_TIMER_PPI; i++)
+               arch_timer_ppi[i] = irq_of_parse_and_map(np, i);
+
+       arch_timer_detect_rate(NULL, np);
+
+       arch_timer_c3stop = !of_property_read_bool(np, "always-on");
+
+       /*
+        * If we cannot rely on firmware initializing the timer registers then
+        * we should use the physical timers instead.
+        */
+       if (IS_ENABLED(CONFIG_ARM) &&
+           of_property_read_bool(np, "arm,cpu-registers-not-fw-configured"))
+                       arch_timer_use_virtual = false;
+
+       arch_timer_init();
+}
+CLOCKSOURCE_OF_DECLARE(armv7_arch_timer, "arm,armv7-timer", arch_timer_of_init);
+CLOCKSOURCE_OF_DECLARE(armv8_arch_timer, "arm,armv8-timer", arch_timer_of_init);
+
+static void __init arch_timer_mem_init(struct device_node *np)
+{
+       struct device_node *frame, *best_frame = NULL;
+       void __iomem *cntctlbase, *base;
+       unsigned int irq;
+       u32 cnttidr;
+
+       arch_timers_present |= ARCH_MEM_TIMER;
+       cntctlbase = of_iomap(np, 0);
+       if (!cntctlbase) {
+               pr_err("arch_timer: Can't find CNTCTLBase\n");
+               return;
+       }
+
+       cnttidr = readl_relaxed(cntctlbase + CNTTIDR);
+       iounmap(cntctlbase);
+
+       /*
+        * Try to find a virtual capable frame. Otherwise fall back to a
+        * physical capable frame.
+        */
+       for_each_available_child_of_node(np, frame) {
+               int n;
+
+               if (of_property_read_u32(frame, "frame-number", &n)) {
+                       pr_err("arch_timer: Missing frame-number\n");
+                       of_node_put(best_frame);
+                       of_node_put(frame);
+                       return;
+               }
+
+               if (cnttidr & CNTTIDR_VIRT(n)) {
+                       of_node_put(best_frame);
+                       best_frame = frame;
+                       arch_timer_mem_use_virtual = true;
+                       break;
+               }
+               of_node_put(best_frame);
+               best_frame = of_node_get(frame);
+       }
+
+       base = arch_counter_base = of_iomap(best_frame, 0);
+       if (!base) {
+               pr_err("arch_timer: Can't map frame's registers\n");
+               of_node_put(best_frame);
+               return;
+       }
+
+       if (arch_timer_mem_use_virtual)
+               irq = irq_of_parse_and_map(best_frame, 1);
        else
-               arch_timer_read_counter = arch_counter_get_cntpct;
+               irq = irq_of_parse_and_map(best_frame, 0);
+       of_node_put(best_frame);
+       if (!irq) {
+               pr_err("arch_timer: Frame missing %s irq",
+                      arch_timer_mem_use_virtual ? "virt" : "phys");
+               return;
+       }
 
-       arch_timer_register();
-       arch_timer_arch_init();
+       arch_timer_detect_rate(base, np);
+       arch_timer_mem_register(base, irq);
+       arch_timer_common_init();
+}
+CLOCKSOURCE_OF_DECLARE(armv7_arch_timer_mem, "arm,armv7-timer-mem",
+                      arch_timer_mem_init);
+
+#ifdef CONFIG_ACPI
+static int __init map_generic_timer_interrupt(u32 interrupt, u32 flags)
+{
+       int trigger, polarity;
+
+       if (!interrupt)
+               return 0;
+
+       trigger = (flags & ACPI_GTDT_INTERRUPT_MODE) ? ACPI_EDGE_SENSITIVE
+                       : ACPI_LEVEL_SENSITIVE;
+
+       polarity = (flags & ACPI_GTDT_INTERRUPT_POLARITY) ? ACPI_ACTIVE_LOW
+                       : ACPI_ACTIVE_HIGH;
+
+       return acpi_register_gsi(NULL, interrupt, trigger, polarity);
+}
+
+/* Initialize per-processor generic timer */
+static int __init arch_timer_acpi_init(struct acpi_table_header *table)
+{
+       struct acpi_table_gtdt *gtdt;
+
+       if (arch_timers_present & ARCH_CP15_TIMER) {
+               pr_warn("arch_timer: already initialized, skipping\n");
+               return -EINVAL;
+       }
+
+       gtdt = container_of(table, struct acpi_table_gtdt, header);
+
+       arch_timers_present |= ARCH_CP15_TIMER;
+
+       arch_timer_ppi[PHYS_SECURE_PPI] =
+               map_generic_timer_interrupt(gtdt->secure_el1_interrupt,
+               gtdt->secure_el1_flags);
+
+       arch_timer_ppi[PHYS_NONSECURE_PPI] =
+               map_generic_timer_interrupt(gtdt->non_secure_el1_interrupt,
+               gtdt->non_secure_el1_flags);
+
+       arch_timer_ppi[VIRT_PPI] =
+               map_generic_timer_interrupt(gtdt->virtual_timer_interrupt,
+               gtdt->virtual_timer_flags);
+
+       arch_timer_ppi[HYP_PPI] =
+               map_generic_timer_interrupt(gtdt->non_secure_el2_interrupt,
+               gtdt->non_secure_el2_flags);
+
+       /* Get the frequency from CNTFRQ */
+       arch_timer_detect_rate(NULL, NULL);
+
+       /* Always-on capability */
+       arch_timer_c3stop = !(gtdt->non_secure_el1_flags & ACPI_GTDT_ALWAYS_ON);
+
+       arch_timer_init();
+       return 0;
 }
-CLOCKSOURCE_OF_DECLARE(armv7_arch_timer, "arm,armv7-timer", arch_timer_init);
-CLOCKSOURCE_OF_DECLARE(armv8_arch_timer, "arm,armv8-timer", arch_timer_init);
+CLOCKSOURCE_ACPI_DECLARE(arch_timer, ACPI_SIG_GTDT, arch_timer_acpi_init);
+#endif