Merge branch 'timers/clockevents-next' of git://git.linaro.org/people/dlezcano/clockevents into timers/core

* Support for memory mapped arch_timers
* Trivial fixes to the moxart timer code
* Documentation updates

Trivial conflicts in drivers/clocksource/arm_arch_timer.c. Fixed up
the newly added __cpuinit annotations as well.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

7 files changed, 460 insertions, 100 deletions

diff --git a/Documentation/devicetree/bindings/arm/arch_timer.txt b/Documentation/devicetree/bindings/arm/arch_timer.txt
index 20746e5abe6f..06fc7602593a 100644
--- a/Documentation/devicetree/bindings/arm/arch_timer.txt
+++ b/Documentation/devicetree/bindings/arm/arch_timer.txt
@@ -1,10 +1,14 @@
 * ARM architected timer
 
-ARM cores may have a per-core architected timer, which provides per-cpu timers.
+ARM cores may have a per-core architected timer, which provides per-cpu timers,
+or a memory mapped architected timer, which provides up to 8 frames with a
+physical and optional virtual timer per frame.
 
-The timer is attached to a GIC to deliver its per-processor interrupts.
+The per-core architected timer is attached to a GIC to deliver its
+per-processor interrupts via PPIs. The memory mapped timer is attached to a GIC
+to deliver its interrupts via SPIs.
 
-** Timer node properties:
+** CP15 Timer node properties:
 
 - compatible : Should at least contain one of
         "arm,armv7-timer"
@@ -26,3 +30,52 @@ Example:
                              <1 10 0xf08>;
                 clock-frequency = <100000000>;
         };
+
+** Memory mapped timer node properties:
+
+- compatible : Should at least contain "arm,armv7-timer-mem".
+
+- clock-frequency : The frequency of the main counter, in Hz. Optional.
+
+- reg : The control frame base address.
+
+Note that #address-cells, #size-cells, and ranges shall be present to ensure
+the CPU can address a frame's registers.
+
+A timer node has up to 8 frame sub-nodes, each with the following properties:
+
+- frame-number: 0 to 7.
+
+- interrupts : Interrupt list for physical and virtual timers in that order.
+  The virtual timer interrupt is optional.
+
+- reg : The first and second view base addresses in that order. The second view
+  base address is optional.
+
+- status : "disabled" indicates the frame is not available for use. Optional.
+
+Example:
+
+        timer@f0000000 {
+                compatible = "arm,armv7-timer-mem";
+                #address-cells = <1>;
+                #size-cells = <1>;
+                ranges;
+                reg = <0xf0000000 0x1000>;
+                clock-frequency = <50000000>;
+
+                frame@f0001000 {
+                        frame-number = <0>
+                        interrupts = <0 13 0x8>,
+                                     <0 14 0x8>;
+                        reg = <0xf0001000 0x1000>,
+                              <0xf0002000 0x1000>;
+                };
+
+                frame@f0003000 {
+                        frame-number = <1>
+                        interrupts = <0 15 0x8>;
+                        reg = <0xf0003000 0x1000>;
+                        status = "disabled";
+                };
+        };
diff --git a/Documentation/devicetree/bindings/timer/moxa,moxart-timer.txt b/Documentation/devicetree/bindings/timer/moxa,moxart-timer.txt
index 77c4cfa198ee..da2d510cae47 100644
--- a/Documentation/devicetree/bindings/timer/moxa,moxart-timer.txt
+++ b/Documentation/devicetree/bindings/timer/moxa,moxart-timer.txt
@@ -2,10 +2,10 @@ MOXA ART timer
 
 Required properties:
 
-- compatible : Should be "moxa,moxart-timer"
+- compatible : Must be "moxa,moxart-timer"
 - reg : Should contain registers location and length
 - interrupts : Should contain the timer interrupt number
-- clocks : Should contain phandle for APB clock "clkapb"
+- clocks : Should contain phandle for the clock that drives the counter
 
 Example:
 
@@ -13,5 +13,5 @@ Example:
                 compatible = "moxa,moxart-timer";
                 reg = <0x98400000 0x42>;
                 interrupts = <19 1>;
-                clocks = <&clkapb>;
+                clocks = <&coreclk>;
         };
diff --git a/arch/arm/include/asm/arch_timer.h b/arch/arm/include/asm/arch_timer.h
index e406d575c94f..5665134bfa3e 100644
--- a/arch/arm/include/asm/arch_timer.h
+++ b/arch/arm/include/asm/arch_timer.h
@@ -17,7 +17,8 @@ int arch_timer_arch_init(void);
  * nicely work out which register we want, and chuck away the rest of
  * the code. At least it does so with a recent GCC (4.6.3).
  */
-static inline void arch_timer_reg_write(const int access, const int reg, u32 val)
+static __always_inline
+void arch_timer_reg_write_cp15(int access, enum arch_timer_reg reg, u32 val)
 {
         if (access == ARCH_TIMER_PHYS_ACCESS) {
                 switch (reg) {
@@ -28,9 +29,7 @@ static inline void arch_timer_reg_write(const int access, const int reg, u32 val
                         asm volatile("mcr p15, 0, %0, c14, c2, 0" : : "r" (val));
                         break;
                 }
-        }
-
-        if (access == ARCH_TIMER_VIRT_ACCESS) {
+        } else if (access == ARCH_TIMER_VIRT_ACCESS) {
                 switch (reg) {
                 case ARCH_TIMER_REG_CTRL:
                         asm volatile("mcr p15, 0, %0, c14, c3, 1" : : "r" (val));
@@ -44,7 +43,8 @@ static inline void arch_timer_reg_write(const int access, const int reg, u32 val
         isb();
 }
 
-static inline u32 arch_timer_reg_read(const int access, const int reg)
+static __always_inline
+u32 arch_timer_reg_read_cp15(int access, enum arch_timer_reg reg)
 {
         u32 val = 0;
 
@@ -57,9 +57,7 @@ static inline u32 arch_timer_reg_read(const int access, const int reg)
                         asm volatile("mrc p15, 0, %0, c14, c2, 0" : "=r" (val));
                         break;
                 }
-        }
-
-        if (access == ARCH_TIMER_VIRT_ACCESS) {
+        } else if (access == ARCH_TIMER_VIRT_ACCESS) {
                 switch (reg) {
                 case ARCH_TIMER_REG_CTRL:
                         asm volatile("mrc p15, 0, %0, c14, c3, 1" : "=r" (val));
diff --git a/arch/arm64/include/asm/arch_timer.h b/arch/arm64/include/asm/arch_timer.h
index 98abd476992d..c9f1d2816c2b 100644
--- a/arch/arm64/include/asm/arch_timer.h
+++ b/arch/arm64/include/asm/arch_timer.h
@@ -26,7 +26,13 @@
 
 #include <clocksource/arm_arch_timer.h>
 
-static inline void arch_timer_reg_write(int access, int reg, u32 val)
+/*
+ * These register accessors are marked inline so the compiler can
+ * nicely work out which register we want, and chuck away the rest of
+ * the code.
+ */
+static __always_inline
+void arch_timer_reg_write_cp15(int access, enum arch_timer_reg reg, u32 val)
 {
         if (access == ARCH_TIMER_PHYS_ACCESS) {
                 switch (reg) {
@@ -36,8 +42,6 @@ static inline void arch_timer_reg_write(int access, int reg, u32 val)
                 case ARCH_TIMER_REG_TVAL:
                         asm volatile("msr cntp_tval_el0, %0" : : "r" (val));
                         break;
-                default:
-                        BUILD_BUG();
                 }
         } else if (access == ARCH_TIMER_VIRT_ACCESS) {
                 switch (reg) {
@@ -47,17 +51,14 @@ static inline void arch_timer_reg_write(int access, int reg, u32 val)
                 case ARCH_TIMER_REG_TVAL:
                         asm volatile("msr cntv_tval_el0, %0" : : "r" (val));
                         break;
-                default:
-                        BUILD_BUG();
                 }
-        } else {
-                BUILD_BUG();
         }
 
         isb();
 }
 
-static inline u32 arch_timer_reg_read(int access, int reg)
+static __always_inline
+u32 arch_timer_reg_read_cp15(int access, enum arch_timer_reg reg)
 {
         u32 val;
 
@@ -69,8 +70,6 @@ static inline u32 arch_timer_reg_read(int access, int reg)
                 case ARCH_TIMER_REG_TVAL:
                         asm volatile("mrs %0, cntp_tval_el0" : "=r" (val));
                         break;
-                default:
-                        BUILD_BUG();
                 }
         } else if (access == ARCH_TIMER_VIRT_ACCESS) {
                 switch (reg) {
@@ -80,11 +79,7 @@ static inline u32 arch_timer_reg_read(int access, int reg)
                 case ARCH_TIMER_REG_TVAL:
                         asm volatile("mrs %0, cntv_tval_el0" : "=r" (val));
                         break;
-                default:
-                        BUILD_BUG();
                 }
-        } else {
-                BUILD_BUG();
         }
 
         return val;
diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c
index ffadd836e0b5..fbd9ccd5e114 100644
--- a/drivers/clocksource/arm_arch_timer.c
+++ b/drivers/clocksource/arm_arch_timer.c
@@ -16,13 +16,39 @@
 #include <linux/clockchips.h>
 #include <linux/interrupt.h>
 #include <linux/of_irq.h>
+#include <linux/of_address.h>
 #include <linux/io.h>
+#include <linux/slab.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 +64,83 @@ 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_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;
         }
@@ -72,15 +162,30 @@ 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 void timer_set_mode(const int access, int mode,
+                                  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_reg_read(access, ARCH_TIMER_REG_CTRL, clk);
                 ctrl &= ~ARCH_TIMER_CTRL_ENABLE;
-                arch_timer_reg_write(access, ARCH_TIMER_REG_CTRL, ctrl);
+                arch_timer_reg_write(access, ARCH_TIMER_REG_CTRL, ctrl, clk);
                 break;
         default:
                 break;
@@ -90,60 +195,108 @@ static inline void timer_set_mode(const int access, int mode)
 static void arch_timer_set_mode_virt(enum clock_event_mode mode,
                                      struct clock_event_device *clk)
 {
-        timer_set_mode(ARCH_TIMER_VIRT_ACCESS, mode);
+        timer_set_mode(ARCH_TIMER_VIRT_ACCESS, mode, clk);
 }
 
 static void arch_timer_set_mode_phys(enum clock_event_mode mode,
                                      struct clock_event_device *clk)
 {
-        timer_set_mode(ARCH_TIMER_PHYS_ACCESS, mode);
+        timer_set_mode(ARCH_TIMER_PHYS_ACCESS, mode, clk);
+}
+
+static void arch_timer_set_mode_virt_mem(enum clock_event_mode mode,
+                                         struct clock_event_device *clk)
+{
+        timer_set_mode(ARCH_TIMER_MEM_VIRT_ACCESS, mode, clk);
 }
 
-static inline void set_next_event(const int access, unsigned long evt)
+static void arch_timer_set_mode_phys_mem(enum clock_event_mode mode,
+                                         struct clock_event_device *clk)
+{
+        timer_set_mode(ARCH_TIMER_MEM_PHYS_ACCESS, mode, 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 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) {
+                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_mode = arch_timer_set_mode_virt;
+                        clk->set_next_event = arch_timer_set_next_event_virt;
+                } 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;
+                }
         } 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->name = "arch_mem_timer";
+                clk->rating = 400;
+                clk->cpumask = cpu_all_mask;
+                if (arch_timer_mem_use_virtual) {
+                        clk->set_mode = arch_timer_set_mode_virt_mem;
+                        clk->set_next_event =
+                                arch_timer_set_next_event_virt_mem;
+                } else {
+                        clk->set_mode = arch_timer_set_mode_phys_mem;
+                        clk->set_next_event =
+                                arch_timer_set_next_event_phys_mem;
+                }
         }
 
-        clk->cpumask = cpumask_of(smp_processor_id());
+        clk->set_mode(CLOCK_EVT_MODE_SHUTDOWN, clk);
 
-        clk->set_mode(CLOCK_EVT_MODE_SHUTDOWN, NULL);
+        clockevents_config_and_register(clk, arch_timer_rate, 0xf, 0x7fffffff);
+}
 
-        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);
@@ -158,27 +311,41 @@ static int arch_timer_setup(struct clock_event_device *clk)
         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 (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)
@@ -186,19 +353,35 @@ u32 arch_timer_get_rate(void)
         return arch_timer_rate;
 }
 
-u64 arch_timer_read_counter(void)
+static u64 arch_counter_get_cntvct_mem(void)
 {
-        return arch_counter_get_cntvct();
+        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;
 }
 
+/*
+ * 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)
 {
-        return arch_counter_get_cntvct();
+        return arch_timer_read_counter();
 }
 
 static cycle_t arch_counter_read_cc(const struct cyclecounter *cc)
 {
-        return arch_counter_get_cntvct();
+        return arch_timer_read_counter();
 }
 
 static struct clocksource clocksource_counter = {
@@ -221,6 +404,23 @@ struct timecounter *arch_timer_get_timecounter(void)
         return &timecounter;
 }
 
+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)
+                arch_timer_read_counter = arch_counter_get_cntvct;
+        else
+                arch_timer_read_counter = arch_counter_get_cntvct_mem;
+
+        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);
+}
+
 static void arch_timer_stop(struct clock_event_device *clk)
 {
         pr_debug("arch_timer_teardown disable IRQ%d cpu #%d\n",
@@ -265,22 +465,12 @@ 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_cntvct());
-
         if (arch_timer_use_virtual) {
                 ppi = arch_timer_ppi[VIRT_PPI];
                 err = request_percpu_irq(ppi, arch_timer_handler_virt,
@@ -331,24 +521,77 @@ out:
         return err;
 }
 
+static int __init arch_timer_mem_register(void __iomem *base, unsigned int irq)
+{
+        int ret;
+        irq_handler_t func;
+        struct arch_timer *t;
+
+        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);
+        }
+
+        return ret;
+}
+
+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", },
+        {},
+};
+
+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 (of_find_matching_node(NULL, arch_timer_mem_of_match) &&
+                                !(arch_timers_present & ARCH_MEM_TIMER))
+                        return;
+                if (of_find_matching_node(NULL, arch_timer_of_match) &&
+                                !(arch_timers_present & ARCH_CP15_TIMER))
+                        return;
+        }
+
+        arch_timer_banner(arch_timers_present);
+        arch_counter_register(arch_timers_present);
+        arch_timer_arch_init();
+}
+
 static void __init arch_timer_init(struct device_node *np)
 {
-        u32 freq;
         int i;
 
-        if (arch_timer_get_rate()) {
+        if (arch_timers_present & ARCH_CP15_TIMER) {
                 pr_warn("arch_timer: multiple nodes in dt, skipping\n");
                 return;
         }
 
-        /* Try to determine the frequency from the device tree or CNTFRQ */
-        if (!of_property_read_u32(np, "clock-frequency", &freq))
-                arch_timer_rate = freq;
-
+        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);
-
-        of_node_put(np);
+        arch_timer_detect_rate(NULL, np);
 
         /*
          * If HYP mode is available, we know that the physical timer
@@ -369,7 +612,73 @@ static void __init arch_timer_init(struct device_node *np)
         }
 
         arch_timer_register();
-        arch_timer_arch_init();
+        arch_timer_common_init();
 }
 CLOCKSOURCE_OF_DECLARE(armv7_arch_timer, "arm,armv7-timer", arch_timer_init);
 CLOCKSOURCE_OF_DECLARE(armv8_arch_timer, "arm,armv8-timer", arch_timer_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
+                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_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);
diff --git a/drivers/clocksource/moxart_timer.c b/drivers/clocksource/moxart_timer.c
index 08a5943b3e42..5eb2c35932b1 100644
--- a/drivers/clocksource/moxart_timer.c
+++ b/drivers/clocksource/moxart_timer.c
@@ -20,6 +20,7 @@
 #include <linux/of_irq.h>
 #include <linux/io.h>
 #include <linux/clocksource.h>
+#include <linux/bitops.h>
 
 #define TIMER1_BASE             0x00
 #define TIMER2_BASE             0x10
diff --git a/include/clocksource/arm_arch_timer.h b/include/clocksource/arm_arch_timer.h
index c463ce990c48..93b7f96f9c59 100644
--- a/include/clocksource/arm_arch_timer.h
+++ b/include/clocksource/arm_arch_timer.h
@@ -23,16 +23,20 @@
 #define ARCH_TIMER_CTRL_IT_MASK         (1 << 1)
 #define ARCH_TIMER_CTRL_IT_STAT         (1 << 2)
 
-#define ARCH_TIMER_REG_CTRL             0
-#define ARCH_TIMER_REG_TVAL             1
+enum arch_timer_reg {
+        ARCH_TIMER_REG_CTRL,
+        ARCH_TIMER_REG_TVAL,
+};
 
 #define ARCH_TIMER_PHYS_ACCESS          0
 #define ARCH_TIMER_VIRT_ACCESS          1
+#define ARCH_TIMER_MEM_PHYS_ACCESS      2
+#define ARCH_TIMER_MEM_VIRT_ACCESS      3
 
 #ifdef CONFIG_ARM_ARCH_TIMER
 
 extern u32 arch_timer_get_rate(void);
-extern u64 arch_timer_read_counter(void);
+extern u64 (*arch_timer_read_counter)(void);
 extern struct timecounter *arch_timer_get_timecounter(void);
 
 #else