clocksource/arm_arch_timer: Fix arch_timer_mem_find_best_frame()
[sfrench/cifs-2.6.git] / drivers / clocksource / arm_arch_timer.c
index 5c114da0ed71c325ea69e2d0e09e636e3f3f4f7d..4bed671e490e0b15d79fd432f3d85dacfd094a96 100644 (file)
@@ -33,6 +33,9 @@
 
 #include <clocksource/arm_arch_timer.h>
 
+#undef pr_fmt
+#define pr_fmt(fmt) "arch_timer: " fmt
+
 #define CNTTIDR                0x08
 #define CNTTIDR_VIRT(n)        (BIT(1) << ((n) * 4))
 
@@ -52,8 +55,6 @@
 #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;
@@ -66,23 +67,15 @@ struct arch_timer {
 #define to_arch_timer(e) container_of(e, struct arch_timer, evt)
 
 static u32 arch_timer_rate;
-
-enum ppi_nr {
-       PHYS_SECURE_PPI,
-       PHYS_NONSECURE_PPI,
-       VIRT_PPI,
-       HYP_PPI,
-       MAX_TIMER_PPI
-};
-
-static int arch_timer_ppi[MAX_TIMER_PPI];
+static int arch_timer_ppi[ARCH_TIMER_MAX_TIMER_PPI];
 
 static struct clock_event_device __percpu *arch_timer_evt;
 
-static enum ppi_nr arch_timer_uses_ppi = VIRT_PPI;
+static enum arch_timer_ppi_nr arch_timer_uses_ppi = ARCH_TIMER_VIRT_PPI;
 static bool arch_timer_c3stop;
 static bool arch_timer_mem_use_virtual;
 static bool arch_counter_suspend_stop;
+static bool vdso_default = true;
 
 static bool evtstrm_enable = IS_ENABLED(CONFIG_ARM_ARCH_TIMER_EVTSTREAM);
 
@@ -189,6 +182,12 @@ static struct cyclecounter cyclecounter __ro_after_init = {
        .mask   = CLOCKSOURCE_MASK(56),
 };
 
+struct ate_acpi_oem_info {
+       char oem_id[ACPI_OEM_ID_SIZE + 1];
+       char oem_table_id[ACPI_OEM_TABLE_ID_SIZE + 1];
+       u32 oem_revision;
+};
+
 #ifdef CONFIG_FSL_ERRATUM_A008585
 /*
  * The number of retries is an arbitrary value well beyond the highest number
@@ -263,6 +262,40 @@ static u64 notrace hisi_161010101_read_cntvct_el0(void)
 {
        return __hisi_161010101_read_reg(cntvct_el0);
 }
+
+static struct ate_acpi_oem_info hisi_161010101_oem_info[] = {
+       /*
+        * Note that trailing spaces are required to properly match
+        * the OEM table information.
+        */
+       {
+               .oem_id         = "HISI  ",
+               .oem_table_id   = "HIP05   ",
+               .oem_revision   = 0,
+       },
+       {
+               .oem_id         = "HISI  ",
+               .oem_table_id   = "HIP06   ",
+               .oem_revision   = 0,
+       },
+       {
+               .oem_id         = "HISI  ",
+               .oem_table_id   = "HIP07   ",
+               .oem_revision   = 0,
+       },
+       { /* Sentinel indicating the end of the OEM array */ },
+};
+#endif
+
+#ifdef CONFIG_ARM64_ERRATUM_858921
+static u64 notrace arm64_858921_read_cntvct_el0(void)
+{
+       u64 old, new;
+
+       old = read_sysreg(cntvct_el0);
+       new = read_sysreg(cntvct_el0);
+       return (((old ^ new) >> 32) & 1) ? old : new;
+}
 #endif
 
 #ifdef CONFIG_ARM_ARCH_TIMER_OOL_WORKAROUND
@@ -291,14 +324,14 @@ static void erratum_set_next_event_tval_generic(const int access, unsigned long
        arch_timer_reg_write(access, ARCH_TIMER_REG_CTRL, ctrl, clk);
 }
 
-static int erratum_set_next_event_tval_virt(unsigned long evt,
+static __maybe_unused int erratum_set_next_event_tval_virt(unsigned long evt,
                                            struct clock_event_device *clk)
 {
        erratum_set_next_event_tval_generic(ARCH_TIMER_VIRT_ACCESS, evt, clk);
        return 0;
 }
 
-static int erratum_set_next_event_tval_phys(unsigned long evt,
+static __maybe_unused int erratum_set_next_event_tval_phys(unsigned long evt,
                                            struct clock_event_device *clk)
 {
        erratum_set_next_event_tval_generic(ARCH_TIMER_PHYS_ACCESS, evt, clk);
@@ -329,6 +362,24 @@ static const struct arch_timer_erratum_workaround ool_workarounds[] = {
                .set_next_event_phys = erratum_set_next_event_tval_phys,
                .set_next_event_virt = erratum_set_next_event_tval_virt,
        },
+       {
+               .match_type = ate_match_acpi_oem_info,
+               .id = hisi_161010101_oem_info,
+               .desc = "HiSilicon erratum 161010101",
+               .read_cntp_tval_el0 = hisi_161010101_read_cntp_tval_el0,
+               .read_cntv_tval_el0 = hisi_161010101_read_cntv_tval_el0,
+               .read_cntvct_el0 = hisi_161010101_read_cntvct_el0,
+               .set_next_event_phys = erratum_set_next_event_tval_phys,
+               .set_next_event_virt = erratum_set_next_event_tval_virt,
+       },
+#endif
+#ifdef CONFIG_ARM64_ERRATUM_858921
+       {
+               .match_type = ate_match_local_cap_id,
+               .id = (void *)ARM64_WORKAROUND_858921,
+               .desc = "ARM erratum 858921",
+               .read_cntvct_el0 = arm64_858921_read_cntvct_el0,
+       },
 #endif
 };
 
@@ -351,6 +402,28 @@ bool arch_timer_check_local_cap_erratum(const struct arch_timer_erratum_workarou
        return this_cpu_has_cap((uintptr_t)wa->id);
 }
 
+
+static
+bool arch_timer_check_acpi_oem_erratum(const struct arch_timer_erratum_workaround *wa,
+                                      const void *arg)
+{
+       static const struct ate_acpi_oem_info empty_oem_info = {};
+       const struct ate_acpi_oem_info *info = wa->id;
+       const struct acpi_table_header *table = arg;
+
+       /* Iterate over the ACPI OEM info array, looking for a match */
+       while (memcmp(info, &empty_oem_info, sizeof(*info))) {
+               if (!memcmp(info->oem_id, table->oem_id, ACPI_OEM_ID_SIZE) &&
+                   !memcmp(info->oem_table_id, table->oem_table_id, ACPI_OEM_TABLE_ID_SIZE) &&
+                   info->oem_revision == table->oem_revision)
+                       return true;
+
+               info++;
+       }
+
+       return false;
+}
+
 static const struct arch_timer_erratum_workaround *
 arch_timer_iterate_errata(enum arch_timer_erratum_match_type type,
                          ate_match_fn_t match_fn,
@@ -383,6 +456,17 @@ void arch_timer_enable_workaround(const struct arch_timer_erratum_workaround *wa
        }
 
        static_branch_enable(&arch_timer_read_ool_enabled);
+
+       /*
+        * Don't use the vdso fastpath if errata require using the
+        * out-of-line counter accessor. We may change our mind pretty
+        * late in the game (with a per-CPU erratum, for example), so
+        * change both the default value and the vdso itself.
+        */
+       if (wa->read_cntvct_el0) {
+               clocksource_counter.archdata.vdso_direct = false;
+               vdso_default = false;
+       }
 }
 
 static void arch_timer_check_ool_workaround(enum arch_timer_erratum_match_type type,
@@ -400,6 +484,9 @@ static void arch_timer_check_ool_workaround(enum arch_timer_erratum_match_type t
                match_fn = arch_timer_check_local_cap_erratum;
                local = true;
                break;
+       case ate_match_acpi_oem_info:
+               match_fn = arch_timer_check_acpi_oem_erratum;
+               break;
        default:
                WARN_ON(1);
                return;
@@ -443,11 +530,19 @@ static void arch_timer_check_ool_workaround(enum arch_timer_erratum_match_type t
        __val;                                                          \
 })
 
+static bool arch_timer_this_cpu_has_cntvct_wa(void)
+{
+       const struct arch_timer_erratum_workaround *wa;
+
+       wa = __this_cpu_read(timer_unstable_counter_workaround);
+       return wa && wa->read_cntvct_el0;
+}
 #else
 #define arch_timer_check_ool_workaround(t,a)           do { } while(0)
 #define erratum_set_next_event_tval_virt(...)          ({BUG(); 0;})
 #define erratum_set_next_event_tval_phys(...)          ({BUG(); 0;})
 #define erratum_handler(fn, r, ...)                    ({false;})
+#define arch_timer_this_cpu_has_cntvct_wa()            ({false;})
 #endif /* CONFIG_ARM_ARCH_TIMER_OOL_WORKAROUND */
 
 static __always_inline irqreturn_t timer_handler(const int access,
@@ -580,7 +675,7 @@ static void __arch_timer_setup(unsigned type,
 {
        clk->features = CLOCK_EVT_FEAT_ONESHOT;
 
-       if (type == ARCH_CP15_TIMER) {
+       if (type == ARCH_TIMER_TYPE_CP15) {
                if (arch_timer_c3stop)
                        clk->features |= CLOCK_EVT_FEAT_C3STOP;
                clk->name = "arch_sys_timer";
@@ -588,14 +683,14 @@ static void __arch_timer_setup(unsigned type,
                clk->cpumask = cpumask_of(smp_processor_id());
                clk->irq = arch_timer_ppi[arch_timer_uses_ppi];
                switch (arch_timer_uses_ppi) {
-               case VIRT_PPI:
+               case ARCH_TIMER_VIRT_PPI:
                        clk->set_state_shutdown = arch_timer_shutdown_virt;
                        clk->set_state_oneshot_stopped = arch_timer_shutdown_virt;
                        clk->set_next_event = arch_timer_set_next_event_virt;
                        break;
-               case PHYS_SECURE_PPI:
-               case PHYS_NONSECURE_PPI:
-               case HYP_PPI:
+               case ARCH_TIMER_PHYS_SECURE_PPI:
+               case ARCH_TIMER_PHYS_NONSECURE_PPI:
+               case ARCH_TIMER_HYP_PPI:
                        clk->set_state_shutdown = arch_timer_shutdown_phys;
                        clk->set_state_oneshot_stopped = arch_timer_shutdown_phys;
                        clk->set_next_event = arch_timer_set_next_event_phys;
@@ -660,23 +755,31 @@ static void arch_counter_set_user_access(void)
 {
        u32 cntkctl = arch_timer_get_cntkctl();
 
-       /* Disable user access to the timers and the physical counter */
+       /* Disable user access to the timers and both counters */
        /* Also disable virtual event stream */
        cntkctl &= ~(ARCH_TIMER_USR_PT_ACCESS_EN
                        | ARCH_TIMER_USR_VT_ACCESS_EN
+                       | ARCH_TIMER_USR_VCT_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;
+       /*
+        * Enable user access to the virtual counter if it doesn't
+        * need to be workaround. The vdso may have been already
+        * disabled though.
+        */
+       if (arch_timer_this_cpu_has_cntvct_wa())
+               pr_info("CPU%d: Trapping CNTVCT access\n", smp_processor_id());
+       else
+               cntkctl |= ARCH_TIMER_USR_VCT_ACCESS_EN;
 
        arch_timer_set_cntkctl(cntkctl);
 }
 
 static bool arch_timer_has_nonsecure_ppi(void)
 {
-       return (arch_timer_uses_ppi == PHYS_SECURE_PPI &&
-               arch_timer_ppi[PHYS_NONSECURE_PPI]);
+       return (arch_timer_uses_ppi == ARCH_TIMER_PHYS_SECURE_PPI &&
+               arch_timer_ppi[ARCH_TIMER_PHYS_NONSECURE_PPI]);
 }
 
 static u32 check_ppi_trigger(int irq)
@@ -697,14 +800,15 @@ static int arch_timer_starting_cpu(unsigned int cpu)
        struct clock_event_device *clk = this_cpu_ptr(arch_timer_evt);
        u32 flags;
 
-       __arch_timer_setup(ARCH_CP15_TIMER, clk);
+       __arch_timer_setup(ARCH_TIMER_TYPE_CP15, clk);
 
        flags = check_ppi_trigger(arch_timer_ppi[arch_timer_uses_ppi]);
        enable_percpu_irq(arch_timer_ppi[arch_timer_uses_ppi], flags);
 
        if (arch_timer_has_nonsecure_ppi()) {
-               flags = check_ppi_trigger(arch_timer_ppi[PHYS_NONSECURE_PPI]);
-               enable_percpu_irq(arch_timer_ppi[PHYS_NONSECURE_PPI], flags);
+               flags = check_ppi_trigger(arch_timer_ppi[ARCH_TIMER_PHYS_NONSECURE_PPI]);
+               enable_percpu_irq(arch_timer_ppi[ARCH_TIMER_PHYS_NONSECURE_PPI],
+                                 flags);
        }
 
        arch_counter_set_user_access();
@@ -714,43 +818,39 @@ static int arch_timer_starting_cpu(unsigned int cpu)
        return 0;
 }
 
-static void
-arch_timer_detect_rate(void __iomem *cntbase, struct device_node *np)
+/*
+ * For historical reasons, when probing with DT we use whichever (non-zero)
+ * rate was probed first, and don't verify that others match. If the first node
+ * probed has a clock-frequency property, this overrides the HW register.
+ */
+static void arch_timer_of_configure_rate(u32 rate, struct device_node *np)
 {
        /* Who has more than one independent system counter? */
        if (arch_timer_rate)
                return;
 
-       /*
-        * 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();
-       }
+       if (of_property_read_u32(np, "clock-frequency", &arch_timer_rate))
+               arch_timer_rate = rate;
 
        /* Check the timer frequency. */
        if (arch_timer_rate == 0)
-               pr_warn("Architected timer frequency not available\n");
+               pr_warn("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,
-                    type & ARCH_CP15_TIMER ?
-                    (arch_timer_uses_ppi == VIRT_PPI) ? "virt" : "phys" :
+       pr_info("%s%s%s timer(s) running at %lu.%02luMHz (%s%s%s).\n",
+               type & ARCH_TIMER_TYPE_CP15 ? "cp15" : "",
+               type == (ARCH_TIMER_TYPE_CP15 | ARCH_TIMER_TYPE_MEM) ?
+                       " and " : "",
+               type & ARCH_TIMER_TYPE_MEM ? "mmio" : "",
+               (unsigned long)arch_timer_rate / 1000000,
+               (unsigned long)(arch_timer_rate / 10000) % 100,
+               type & ARCH_TIMER_TYPE_CP15 ?
+                       (arch_timer_uses_ppi == ARCH_TIMER_VIRT_PPI) ? "virt" : "phys" :
                        "",
-                    type == (ARCH_CP15_TIMER | ARCH_MEM_TIMER) ?  "/" : "",
-                    type & ARCH_MEM_TIMER ?
+               type == (ARCH_TIMER_TYPE_CP15 | ARCH_TIMER_TYPE_MEM) ? "/" : "",
+               type & ARCH_TIMER_TYPE_MEM ?
                        arch_timer_mem_use_virtual ? "virt" : "phys" :
                        "");
 }
@@ -785,22 +885,14 @@ 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_uses_ppi == VIRT_PPI)
+       if (type & ARCH_TIMER_TYPE_CP15) {
+               if (IS_ENABLED(CONFIG_ARM64) ||
+                   arch_timer_uses_ppi == ARCH_TIMER_VIRT_PPI)
                        arch_timer_read_counter = arch_counter_get_cntvct;
                else
                        arch_timer_read_counter = arch_counter_get_cntpct;
 
-               clocksource_counter.archdata.vdso_direct = true;
-
-#ifdef CONFIG_ARM_ARCH_TIMER_OOL_WORKAROUND
-               /*
-                * Don't use the vdso fastpath if errata require using
-                * the out-of-line counter accessor.
-                */
-               if (static_branch_unlikely(&arch_timer_read_ool_enabled))
-                       clocksource_counter.archdata.vdso_direct = false;
-#endif
+               clocksource_counter.archdata.vdso_direct = vdso_default;
        } else {
                arch_timer_read_counter = arch_counter_get_cntvct_mem;
        }
@@ -820,12 +912,11 @@ static void __init arch_counter_register(unsigned type)
 
 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());
+       pr_debug("disable IRQ%d cpu #%d\n", clk->irq, smp_processor_id());
 
        disable_percpu_irq(arch_timer_ppi[arch_timer_uses_ppi]);
        if (arch_timer_has_nonsecure_ppi())
-               disable_percpu_irq(arch_timer_ppi[PHYS_NONSECURE_PPI]);
+               disable_percpu_irq(arch_timer_ppi[ARCH_TIMER_PHYS_NONSECURE_PPI]);
 
        clk->set_state_shutdown(clk);
 }
@@ -888,24 +979,24 @@ static int __init arch_timer_register(void)
 
        ppi = arch_timer_ppi[arch_timer_uses_ppi];
        switch (arch_timer_uses_ppi) {
-       case VIRT_PPI:
+       case ARCH_TIMER_VIRT_PPI:
                err = request_percpu_irq(ppi, arch_timer_handler_virt,
                                         "arch_timer", arch_timer_evt);
                break;
-       case PHYS_SECURE_PPI:
-       case PHYS_NONSECURE_PPI:
+       case ARCH_TIMER_PHYS_SECURE_PPI:
+       case ARCH_TIMER_PHYS_NONSECURE_PPI:
                err = request_percpu_irq(ppi, arch_timer_handler_phys,
                                         "arch_timer", arch_timer_evt);
-               if (!err && arch_timer_ppi[PHYS_NONSECURE_PPI]) {
-                       ppi = arch_timer_ppi[PHYS_NONSECURE_PPI];
+               if (!err && arch_timer_has_nonsecure_ppi()) {
+                       ppi = arch_timer_ppi[ARCH_TIMER_PHYS_NONSECURE_PPI];
                        err = request_percpu_irq(ppi, arch_timer_handler_phys,
                                                 "arch_timer", arch_timer_evt);
                        if (err)
-                               free_percpu_irq(arch_timer_ppi[PHYS_SECURE_PPI],
+                               free_percpu_irq(arch_timer_ppi[ARCH_TIMER_PHYS_SECURE_PPI],
                                                arch_timer_evt);
                }
                break;
-       case HYP_PPI:
+       case ARCH_TIMER_HYP_PPI:
                err = request_percpu_irq(ppi, arch_timer_handler_phys,
                                         "arch_timer", arch_timer_evt);
                break;
@@ -914,8 +1005,7 @@ static int __init arch_timer_register(void)
        }
 
        if (err) {
-               pr_err("arch_timer: can't register interrupt %d (%d)\n",
-                      ppi, err);
+               pr_err("can't register interrupt %d (%d)\n", ppi, err);
                goto out_free;
        }
 
@@ -938,7 +1028,7 @@ out_unreg_cpupm:
 out_unreg_notify:
        free_percpu_irq(arch_timer_ppi[arch_timer_uses_ppi], arch_timer_evt);
        if (arch_timer_has_nonsecure_ppi())
-               free_percpu_irq(arch_timer_ppi[PHYS_NONSECURE_PPI],
+               free_percpu_irq(arch_timer_ppi[ARCH_TIMER_PHYS_NONSECURE_PPI],
                                arch_timer_evt);
 
 out_free:
@@ -959,7 +1049,7 @@ static int __init arch_timer_mem_register(void __iomem *base, unsigned int irq)
 
        t->base = base;
        t->evt.irq = irq;
-       __arch_timer_setup(ARCH_MEM_TIMER, &t->evt);
+       __arch_timer_setup(ARCH_TIMER_TYPE_MEM, &t->evt);
 
        if (arch_timer_mem_use_virtual)
                func = arch_timer_handler_virt_mem;
@@ -968,7 +1058,7 @@ static int __init arch_timer_mem_register(void __iomem *base, unsigned int irq)
 
        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");
+               pr_err("Failed to request mem timer irq\n");
                kfree(t);
        }
 
@@ -986,15 +1076,28 @@ static const struct of_device_id arch_timer_mem_of_match[] __initconst = {
        {},
 };
 
-static bool __init
-arch_timer_needs_probing(int type, const struct of_device_id *matches)
+static bool __init arch_timer_needs_of_probing(void)
 {
        struct device_node *dn;
        bool needs_probing = false;
+       unsigned int mask = ARCH_TIMER_TYPE_CP15 | ARCH_TIMER_TYPE_MEM;
+
+       /* We have two timers, and both device-tree nodes are probed. */
+       if ((arch_timers_present & mask) == mask)
+               return false;
 
-       dn = of_find_matching_node(NULL, matches);
-       if (dn && of_device_is_available(dn) && !(arch_timers_present & type))
+       /*
+        * Only one type of timer is probed,
+        * check if we have another type of timer node in device-tree.
+        */
+       if (arch_timers_present & ARCH_TIMER_TYPE_CP15)
+               dn = of_find_matching_node(NULL, arch_timer_mem_of_match);
+       else
+               dn = of_find_matching_node(NULL, arch_timer_of_match);
+
+       if (dn && of_device_is_available(dn))
                needs_probing = true;
+
        of_node_put(dn);
 
        return needs_probing;
@@ -1002,82 +1105,61 @@ arch_timer_needs_probing(int type, const struct of_device_id *matches)
 
 static int __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 0;
-               if (arch_timer_needs_probing(ARCH_CP15_TIMER, arch_timer_of_match))
-                       return 0;
-       }
-
        arch_timer_banner(arch_timers_present);
        arch_counter_register(arch_timers_present);
        return arch_timer_arch_init();
 }
 
-static int __init arch_timer_init(void)
+/**
+ * arch_timer_select_ppi() - Select suitable PPI for the current system.
+ *
+ * If HYP mode is available, we know that the physical timer
+ * has been configured to be accessible from PL1. Use it, so
+ * that a guest can use the virtual timer instead.
+ *
+ * On ARMv8.1 with VH extensions, the kernel runs in HYP. VHE
+ * accesses to CNTP_*_EL1 registers are silently redirected to
+ * their CNTHP_*_EL2 counterparts, and use a different PPI
+ * number.
+ *
+ * If no interrupt provided for virtual timer, we'll have to
+ * stick to the physical timer. It'd better be accessible...
+ * For arm64 we never use the secure interrupt.
+ *
+ * Return: a suitable PPI type for the current system.
+ */
+static enum arch_timer_ppi_nr __init arch_timer_select_ppi(void)
 {
-       int ret;
-       /*
-        * If HYP mode is available, we know that the physical timer
-        * has been configured to be accessible from PL1. Use it, so
-        * that a guest can use the virtual timer instead.
-        *
-        * If no interrupt provided for virtual timer, we'll have to
-        * stick to the physical timer. It'd better be accessible...
-        *
-        * On ARMv8.1 with VH extensions, the kernel runs in HYP. VHE
-        * accesses to CNTP_*_EL1 registers are silently redirected to
-        * their CNTHP_*_EL2 counterparts, and use a different PPI
-        * number.
-        */
-       if (is_hyp_mode_available() || !arch_timer_ppi[VIRT_PPI]) {
-               bool has_ppi;
+       if (is_kernel_in_hyp_mode())
+               return ARCH_TIMER_HYP_PPI;
 
-               if (is_kernel_in_hyp_mode()) {
-                       arch_timer_uses_ppi = HYP_PPI;
-                       has_ppi = !!arch_timer_ppi[HYP_PPI];
-               } else {
-                       arch_timer_uses_ppi = PHYS_SECURE_PPI;
-                       has_ppi = (!!arch_timer_ppi[PHYS_SECURE_PPI] ||
-                                  !!arch_timer_ppi[PHYS_NONSECURE_PPI]);
-               }
+       if (!is_hyp_mode_available() && arch_timer_ppi[ARCH_TIMER_VIRT_PPI])
+               return ARCH_TIMER_VIRT_PPI;
 
-               if (!has_ppi) {
-                       pr_warn("arch_timer: No interrupt available, giving up\n");
-                       return -EINVAL;
-               }
-       }
+       if (IS_ENABLED(CONFIG_ARM64))
+               return ARCH_TIMER_PHYS_NONSECURE_PPI;
 
-       ret = arch_timer_register();
-       if (ret)
-               return ret;
-
-       ret = arch_timer_common_init();
-       if (ret)
-               return ret;
-
-       arch_timer_kvm_info.virtual_irq = arch_timer_ppi[VIRT_PPI];
-       
-       return 0;
+       return ARCH_TIMER_PHYS_SECURE_PPI;
 }
 
 static int __init arch_timer_of_init(struct device_node *np)
 {
-       int i;
+       int i, ret;
+       u32 rate;
 
-       if (arch_timers_present & ARCH_CP15_TIMER) {
-               pr_warn("arch_timer: multiple nodes in dt, skipping\n");
+       if (arch_timers_present & ARCH_TIMER_TYPE_CP15) {
+               pr_warn("multiple nodes in dt, skipping\n");
                return 0;
        }
 
-       arch_timers_present |= ARCH_CP15_TIMER;
-       for (i = PHYS_SECURE_PPI; i < MAX_TIMER_PPI; i++)
+       arch_timers_present |= ARCH_TIMER_TYPE_CP15;
+       for (i = ARCH_TIMER_PHYS_SECURE_PPI; i < ARCH_TIMER_MAX_TIMER_PPI; i++)
                arch_timer_ppi[i] = irq_of_parse_and_map(np, i);
 
-       arch_timer_detect_rate(NULL, np);
+       arch_timer_kvm_info.virtual_irq = arch_timer_ppi[ARCH_TIMER_VIRT_PPI];
+
+       rate = arch_timer_get_cntfrq();
+       arch_timer_of_configure_rate(rate, np);
 
        arch_timer_c3stop = !of_property_read_bool(np, "always-on");
 
@@ -1090,29 +1172,63 @@ static int __init arch_timer_of_init(struct device_node *np)
         */
        if (IS_ENABLED(CONFIG_ARM) &&
            of_property_read_bool(np, "arm,cpu-registers-not-fw-configured"))
-               arch_timer_uses_ppi = PHYS_SECURE_PPI;
+               arch_timer_uses_ppi = ARCH_TIMER_PHYS_SECURE_PPI;
+       else
+               arch_timer_uses_ppi = arch_timer_select_ppi();
+
+       if (!arch_timer_ppi[arch_timer_uses_ppi]) {
+               pr_err("No interrupt available, giving up\n");
+               return -EINVAL;
+       }
 
        /* On some systems, the counter stops ticking when in suspend. */
        arch_counter_suspend_stop = of_property_read_bool(np,
                                                         "arm,no-tick-in-suspend");
 
-       return arch_timer_init();
+       ret = arch_timer_register();
+       if (ret)
+               return ret;
+
+       if (arch_timer_needs_of_probing())
+               return 0;
+
+       return arch_timer_common_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 int __init arch_timer_mem_init(struct device_node *np)
+static u32 __init
+arch_timer_mem_frame_get_cntfrq(struct arch_timer_mem_frame *frame)
 {
-       struct device_node *frame, *best_frame = NULL;
-       void __iomem *cntctlbase, *base;
-       unsigned int irq, ret = -EINVAL;
+       void __iomem *base;
+       u32 rate;
+
+       base = ioremap(frame->cntbase, frame->size);
+       if (!base) {
+               pr_err("Unable to map frame @ %pa\n", &frame->cntbase);
+               return 0;
+       }
+
+       rate = readl_relaxed(frame + CNTFRQ);
+
+       iounmap(frame);
+
+       return rate;
+}
+
+static struct arch_timer_mem_frame * __init
+arch_timer_mem_find_best_frame(struct arch_timer_mem *timer_mem)
+{
+       struct arch_timer_mem_frame *frame, *best_frame = NULL;
+       void __iomem *cntctlbase;
        u32 cnttidr;
+       int i;
 
-       arch_timers_present |= ARCH_MEM_TIMER;
-       cntctlbase = of_iomap(np, 0);
+       cntctlbase = ioremap(timer_mem->cntctlbase, timer_mem->size);
        if (!cntctlbase) {
-               pr_err("arch_timer: Can't find CNTCTLBase\n");
-               return -ENXIO;
+               pr_err("Can't map CNTCTLBase @ %pa\n",
+                       &timer_mem->cntctlbase);
+               return NULL;
        }
 
        cnttidr = readl_relaxed(cntctlbase + CNTTIDR);
@@ -1121,25 +1237,20 @@ static int __init arch_timer_mem_init(struct device_node *np)
         * 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;
-               u32 cntacr;
+       for (i = 0; i < ARCH_TIMER_MEM_MAX_FRAMES; i++) {
+               u32 cntacr = CNTACR_RFRQ | CNTACR_RWPT | CNTACR_RPCT |
+                            CNTACR_RWVT | CNTACR_RVOFF | CNTACR_RVCT;
 
-               if (of_property_read_u32(frame, "frame-number", &n)) {
-                       pr_err("arch_timer: Missing frame-number\n");
-                       of_node_put(frame);
-                       goto out;
-               }
+               frame = &timer_mem->frame[i];
+               if (!frame->valid)
+                       continue;
 
                /* Try enabling everything, and see what sticks */
-               cntacr = CNTACR_RFRQ | CNTACR_RWPT | CNTACR_RPCT |
-                        CNTACR_RWVT | CNTACR_RVOFF | CNTACR_RVCT;
-               writel_relaxed(cntacr, cntctlbase + CNTACR(n));
-               cntacr = readl_relaxed(cntctlbase + CNTACR(n));
+               writel_relaxed(cntacr, cntctlbase + CNTACR(i));
+               cntacr = readl_relaxed(cntctlbase + CNTACR(i));
 
-               if ((cnttidr & CNTTIDR_VIRT(n)) &&
+               if ((cnttidr & CNTTIDR_VIRT(i)) &&
                    !(~cntacr & (CNTACR_RWVT | CNTACR_RVCT))) {
-                       of_node_put(best_frame);
                        best_frame = frame;
                        arch_timer_mem_use_virtual = true;
                        break;
@@ -1148,99 +1259,262 @@ static int __init arch_timer_mem_init(struct device_node *np)
                if (~cntacr & (CNTACR_RWPT | CNTACR_RPCT))
                        continue;
 
-               of_node_put(best_frame);
-               best_frame = of_node_get(frame);
+               best_frame = frame;
        }
 
-       ret= -ENXIO;
-       base = arch_counter_base = of_io_request_and_map(best_frame, 0,
-                                                        "arch_mem_timer");
-       if (IS_ERR(base)) {
-               pr_err("arch_timer: Can't map frame's registers\n");
-               goto out;
-       }
+       iounmap(cntctlbase);
+
+       if (!best_frame)
+               pr_err("Unable to find a suitable frame in timer @ %pa\n",
+                       &timer_mem->cntctlbase);
+
+       return best_frame;
+}
+
+static int __init
+arch_timer_mem_frame_register(struct arch_timer_mem_frame *frame)
+{
+       void __iomem *base;
+       int ret, irq = 0;
 
        if (arch_timer_mem_use_virtual)
-               irq = irq_of_parse_and_map(best_frame, 1);
+               irq = frame->virt_irq;
        else
-               irq = irq_of_parse_and_map(best_frame, 0);
+               irq = frame->phys_irq;
 
-       ret = -EINVAL;
        if (!irq) {
-               pr_err("arch_timer: Frame missing %s irq",
+               pr_err("Frame missing %s irq.\n",
                       arch_timer_mem_use_virtual ? "virt" : "phys");
-               goto out;
+               return -EINVAL;
+       }
+
+       if (!request_mem_region(frame->cntbase, frame->size,
+                               "arch_mem_timer"))
+               return -EBUSY;
+
+       base = ioremap(frame->cntbase, frame->size);
+       if (!base) {
+               pr_err("Can't map frame's registers\n");
+               return -ENXIO;
        }
 
-       arch_timer_detect_rate(base, np);
        ret = arch_timer_mem_register(base, irq);
-       if (ret)
+       if (ret) {
+               iounmap(base);
+               return ret;
+       }
+
+       arch_counter_base = base;
+       arch_timers_present |= ARCH_TIMER_TYPE_MEM;
+
+       return 0;
+}
+
+static int __init arch_timer_mem_of_init(struct device_node *np)
+{
+       struct arch_timer_mem *timer_mem;
+       struct arch_timer_mem_frame *frame;
+       struct device_node *frame_node;
+       struct resource res;
+       int ret = -EINVAL;
+       u32 rate;
+
+       timer_mem = kzalloc(sizeof(*timer_mem), GFP_KERNEL);
+       if (!timer_mem)
+               return -ENOMEM;
+
+       if (of_address_to_resource(np, 0, &res))
                goto out;
+       timer_mem->cntctlbase = res.start;
+       timer_mem->size = resource_size(&res);
 
-       return arch_timer_common_init();
+       for_each_available_child_of_node(np, frame_node) {
+               u32 n;
+               struct arch_timer_mem_frame *frame;
+
+               if (of_property_read_u32(frame_node, "frame-number", &n)) {
+                       pr_err(FW_BUG "Missing frame-number.\n");
+                       of_node_put(frame_node);
+                       goto out;
+               }
+               if (n >= ARCH_TIMER_MEM_MAX_FRAMES) {
+                       pr_err(FW_BUG "Wrong frame-number, only 0-%u are permitted.\n",
+                              ARCH_TIMER_MEM_MAX_FRAMES - 1);
+                       of_node_put(frame_node);
+                       goto out;
+               }
+               frame = &timer_mem->frame[n];
+
+               if (frame->valid) {
+                       pr_err(FW_BUG "Duplicated frame-number.\n");
+                       of_node_put(frame_node);
+                       goto out;
+               }
+
+               if (of_address_to_resource(frame_node, 0, &res)) {
+                       of_node_put(frame_node);
+                       goto out;
+               }
+               frame->cntbase = res.start;
+               frame->size = resource_size(&res);
+
+               frame->virt_irq = irq_of_parse_and_map(frame_node,
+                                                      ARCH_TIMER_VIRT_SPI);
+               frame->phys_irq = irq_of_parse_and_map(frame_node,
+                                                      ARCH_TIMER_PHYS_SPI);
+
+               frame->valid = true;
+       }
+
+       frame = arch_timer_mem_find_best_frame(timer_mem);
+       if (!frame) {
+               ret = -EINVAL;
+               goto out;
+       }
+
+       rate = arch_timer_mem_frame_get_cntfrq(frame);
+       arch_timer_of_configure_rate(rate, np);
+
+       ret = arch_timer_mem_frame_register(frame);
+       if (!ret && !arch_timer_needs_of_probing())
+               ret = arch_timer_common_init();
 out:
-       iounmap(cntctlbase);
-       of_node_put(best_frame);
+       kfree(timer_mem);
        return ret;
 }
 CLOCKSOURCE_OF_DECLARE(armv7_arch_timer_mem, "arm,armv7-timer-mem",
-                      arch_timer_mem_init);
+                      arch_timer_mem_of_init);
 
-#ifdef CONFIG_ACPI
-static int __init map_generic_timer_interrupt(u32 interrupt, u32 flags)
+#ifdef CONFIG_ACPI_GTDT
+static int __init
+arch_timer_mem_verify_cntfrq(struct arch_timer_mem *timer_mem)
 {
-       int trigger, polarity;
+       struct arch_timer_mem_frame *frame;
+       u32 rate;
+       int i;
 
-       if (!interrupt)
-               return 0;
+       for (i = 0; i < ARCH_TIMER_MEM_MAX_FRAMES; i++) {
+               frame = &timer_mem->frame[i];
 
-       trigger = (flags & ACPI_GTDT_INTERRUPT_MODE) ? ACPI_EDGE_SENSITIVE
-                       : ACPI_LEVEL_SENSITIVE;
+               if (!frame->valid)
+                       continue;
+
+               rate = arch_timer_mem_frame_get_cntfrq(frame);
+               if (rate == arch_timer_rate)
+                       continue;
 
-       polarity = (flags & ACPI_GTDT_INTERRUPT_POLARITY) ? ACPI_ACTIVE_LOW
-                       : ACPI_ACTIVE_HIGH;
+               pr_err(FW_BUG "CNTFRQ mismatch: frame @ %pa: (0x%08lx), CPU: (0x%08lx)\n",
+                       &frame->cntbase,
+                       (unsigned long)rate, (unsigned long)arch_timer_rate);
 
-       return acpi_register_gsi(NULL, interrupt, trigger, polarity);
+               return -EINVAL;
+       }
+
+       return 0;
 }
 
-/* Initialize per-processor generic timer */
+static int __init arch_timer_mem_acpi_init(int platform_timer_count)
+{
+       struct arch_timer_mem *timers, *timer;
+       struct arch_timer_mem_frame *frame;
+       int timer_count, i, ret = 0;
+
+       timers = kcalloc(platform_timer_count, sizeof(*timers),
+                           GFP_KERNEL);
+       if (!timers)
+               return -ENOMEM;
+
+       ret = acpi_arch_timer_mem_init(timers, &timer_count);
+       if (ret || !timer_count)
+               goto out;
+
+       for (i = 0; i < timer_count; i++) {
+               ret = arch_timer_mem_verify_cntfrq(&timers[i]);
+               if (ret) {
+                       pr_err("Disabling MMIO timers due to CNTFRQ mismatch\n");
+                       goto out;
+               }
+       }
+
+       /*
+        * While unlikely, it's theoretically possible that none of the frames
+        * in a timer expose the combination of feature we want.
+        */
+       for (i = i; i < timer_count; i++) {
+               timer = &timers[i];
+
+               frame = arch_timer_mem_find_best_frame(timer);
+               if (frame)
+                       break;
+       }
+
+       if (frame)
+               ret = arch_timer_mem_frame_register(frame);
+out:
+       kfree(timers);
+       return ret;
+}
+
+/* Initialize per-processor generic timer and memory-mapped timer(if present) */
 static int __init arch_timer_acpi_init(struct acpi_table_header *table)
 {
-       struct acpi_table_gtdt *gtdt;
+       int ret, platform_timer_count;
 
-       if (arch_timers_present & ARCH_CP15_TIMER) {
-               pr_warn("arch_timer: already initialized, skipping\n");
+       if (arch_timers_present & ARCH_TIMER_TYPE_CP15) {
+               pr_warn("already initialized, skipping\n");
                return -EINVAL;
        }
 
-       gtdt = container_of(table, struct acpi_table_gtdt, header);
+       arch_timers_present |= ARCH_TIMER_TYPE_CP15;
 
-       arch_timers_present |= ARCH_CP15_TIMER;
+       ret = acpi_gtdt_init(table, &platform_timer_count);
+       if (ret) {
+               pr_err("Failed to init GTDT table.\n");
+               return ret;
+       }
 
-       arch_timer_ppi[PHYS_SECURE_PPI] =
-               map_generic_timer_interrupt(gtdt->secure_el1_interrupt,
-               gtdt->secure_el1_flags);
+       arch_timer_ppi[ARCH_TIMER_PHYS_NONSECURE_PPI] =
+               acpi_gtdt_map_ppi(ARCH_TIMER_PHYS_NONSECURE_PPI);
 
-       arch_timer_ppi[PHYS_NONSECURE_PPI] =
-               map_generic_timer_interrupt(gtdt->non_secure_el1_interrupt,
-               gtdt->non_secure_el1_flags);
+       arch_timer_ppi[ARCH_TIMER_VIRT_PPI] =
+               acpi_gtdt_map_ppi(ARCH_TIMER_VIRT_PPI);
 
-       arch_timer_ppi[VIRT_PPI] =
-               map_generic_timer_interrupt(gtdt->virtual_timer_interrupt,
-               gtdt->virtual_timer_flags);
+       arch_timer_ppi[ARCH_TIMER_HYP_PPI] =
+               acpi_gtdt_map_ppi(ARCH_TIMER_HYP_PPI);
 
-       arch_timer_ppi[HYP_PPI] =
-               map_generic_timer_interrupt(gtdt->non_secure_el2_interrupt,
-               gtdt->non_secure_el2_flags);
+       arch_timer_kvm_info.virtual_irq = arch_timer_ppi[ARCH_TIMER_VIRT_PPI];
+
+       /*
+        * When probing via ACPI, we have no mechanism to override the sysreg
+        * CNTFRQ value. This *must* be correct.
+        */
+       arch_timer_rate = arch_timer_get_cntfrq();
+       if (!arch_timer_rate) {
+               pr_err(FW_BUG "frequency not available.\n");
+               return -EINVAL;
+       }
 
-       /* Get the frequency from CNTFRQ */
-       arch_timer_detect_rate(NULL, NULL);
+       arch_timer_uses_ppi = arch_timer_select_ppi();
+       if (!arch_timer_ppi[arch_timer_uses_ppi]) {
+               pr_err("No interrupt available, giving up\n");
+               return -EINVAL;
+       }
 
        /* Always-on capability */
-       arch_timer_c3stop = !(gtdt->non_secure_el1_flags & ACPI_GTDT_ALWAYS_ON);
+       arch_timer_c3stop = acpi_gtdt_c3stop(arch_timer_uses_ppi);
 
-       arch_timer_init();
-       return 0;
+       /* Check for globally applicable workarounds */
+       arch_timer_check_ool_workaround(ate_match_acpi_oem_info, table);
+
+       ret = arch_timer_register();
+       if (ret)
+               return ret;
+
+       if (platform_timer_count &&
+           arch_timer_mem_acpi_init(platform_timer_count))
+               pr_err("Failed to initialize memory-mapped timer.\n");
+
+       return arch_timer_common_init();
 }
 CLOCKSOURCE_ACPI_DECLARE(arch_timer, ACPI_SIG_GTDT, arch_timer_acpi_init);
 #endif