From: Fu Wei fu.wei@linaro.org
Currently Currently arch_timer_detect_rate() tried to handle both the sysreg timer and MMIO timer, with DT-specific fallback code. This gets in the way of implementing deterministic and correct rate probing when using ACPI.
This patch moves this logic out into the (DT-specific) probe functions, allowing different logic to be used in the ACPI case, and making it easier to see which CNTFRQ register is being read in each case.
Signed-off-by: Fu Wei fu.wei@linaro.org [Mark: reword commit message, TODO: rework comments] Signed-off-by: Mark Rutland mark.rutland@arm.com --- drivers/clocksource/arm_arch_timer.c | 58 +++++++++++++++++++----------------- 1 file changed, 30 insertions(+), 28 deletions(-)
diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c index 843f923..1b6a7e6 100644 --- a/drivers/clocksource/arm_arch_timer.c +++ b/drivers/clocksource/arm_arch_timer.c @@ -560,30 +560,6 @@ static u32 arch_timer_mem_get_cntfrq(void __iomem *cntbase) return readl_relaxed(cntbase + CNTFRQ); }
-static void -arch_timer_detect_rate(void __iomem *cntbase, 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 = arch_timer_mem_get_cntfrq(cntbase); - else - arch_timer_rate = arch_timer_get_cntfrq(); - } - - /* Check the timer frequency. */ - if (arch_timer_rate == 0) - pr_warn("frequency not available\n"); -} - static void arch_timer_banner(unsigned type) { pr_info("%s%s%s timer(s) running at %lu.%02luMHz (%s%s%s).\n", @@ -958,7 +934,17 @@ 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); + /* + * Determine the frequency of system counter: + * Try to get the frequency from the device tree. + * If fail, try the sysreg CNTFRQ. Then verify the frequency. + */ + if (of_property_read_u32(np, "clock-frequency", &arch_timer_rate)) + arch_timer_rate = arch_timer_get_cntfrq(); + if (!arch_timer_rate) { + pr_err(FW_BUG "frequency not available.\n"); + return -EINVAL; + }
arch_timer_c3stop = !of_property_read_bool(np, "always-on");
@@ -1069,7 +1055,19 @@ static int __init arch_timer_mem_init(struct device_node *np) goto out; }
- arch_timer_detect_rate(base, np); + /* + * Try to determine the frequency from the device tree, + * if fail, get the frequency from the CNTFRQ reg of MMIO timer. + */ + if (!arch_timer_rate && + of_property_read_u32(np, "clock-frequency", &arch_timer_rate)) + arch_timer_rate = arch_timer_mem_get_cntfrq(base); + if (!arch_timer_rate) { + pr_err(FW_BUG "MMIO frequency not available.\n"); + ret = -EINVAL; + goto out; + } + ret = arch_timer_mem_register(base, irq); if (ret) goto out; @@ -1130,8 +1128,12 @@ 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); + /* Get the frequency from the sysreg CNTFRQ */ + 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]) {