diff options
Diffstat (limited to 'drivers/clocksource/arm_arch_timer.c')
| -rw-r--r-- | drivers/clocksource/arm_arch_timer.c | 41 |
1 files changed, 23 insertions, 18 deletions
diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c index 94de018c65d0..02c5cb86ca83 100644 --- a/drivers/clocksource/arm_arch_timer.c +++ b/drivers/clocksource/arm_arch_timer.c @@ -818,24 +818,19 @@ 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) @@ -1166,6 +1161,7 @@ static int __init arch_timer_init(void) static int __init arch_timer_of_init(struct device_node *np) { int i; + u32 rate; if (arch_timers_present & ARCH_TIMER_TYPE_CP15) { pr_warn("multiple nodes in dt, skipping\n"); @@ -1176,7 +1172,8 @@ static int __init arch_timer_of_init(struct device_node *np) 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); + rate = arch_timer_get_cntfrq; + arch_timer_of_configure_rate(rate, np); arch_timer_c3stop = !of_property_read_bool(np, "always-on"); @@ -1212,7 +1209,7 @@ static int __init arch_timer_mem_init(struct device_node *np) struct device_node *frame, *best_frame = NULL; void __iomem *cntctlbase, *base; unsigned int irq, ret = -EINVAL; - u32 cnttidr; + u32 cnttidr, rate; arch_timers_present |= ARCH_TIMER_TYPE_MEM; cntctlbase = of_iomap(np, 0); @@ -1278,7 +1275,8 @@ static int __init arch_timer_mem_init(struct device_node *np) goto out; } - arch_timer_detect_rate(base, np); + rate = readl(base + CNTFRQ); + arch_timer_of_configure_rate(rate, np); ret = arch_timer_mem_register(base, irq); if (ret) goto out; @@ -1339,8 +1337,15 @@ static int __init arch_timer_acpi_init(struct acpi_table_header *table) 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); + /* + * 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; + } arch_timer_uses_ppi = arch_timer_select_ppi(); if (!arch_timer_ppi[arch_timer_uses_ppi]) { |