From: Fu Wei <fu....@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....@linaro.org>
[Mark: reword commit message, TODO: rework comments]
Signed-off-by: Mark Rutland <mark.rutl...@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]) {
--
2.9.3
