On Fri, Jan 17, 2014 at 12:25:11PM +0000, Hanjun Guo wrote:
ACPI GTDT (Generic Timer Description Table) contains information for arch timer initialization, this patch use this table to probe arm timer.
GTDT table is used for ARM/ARM64 only, please refer to chapter 5.2.24 of ACPI 5.0 spec for detailed inforamtion
Signed-off-by: Amit Daniel Kachhap amit.daniel@samsung.com Signed-off-by: Hanjun Guo hanjun.guo@linaro.org
drivers/clocksource/arm_arch_timer.c | 100 +++++++++++++++++++++++++++++----- 1 file changed, 85 insertions(+), 15 deletions(-)
[...]
+static void __init register_arch_interrupt(u32 interrupt, u32 flags,
int *arch_timer_ppi)+{
- int trigger, polarity;
- if (!interrupt || !arch_timer_ppi)
return;- trigger = (flags & ACPI_GTDT_INTERRUPT_MODE) ? ACPI_EDGE_SENSITIVE
: ACPI_LEVEL_SENSITIVE;- polarity = (flags & ACPI_GTDT_INTERRUPT_POLARITY) ? ACPI_ACTIVE_LOW
: ACPI_ACTIVE_HIGH;- *arch_timer_ppi = acpi_register_gsi(NULL, interrupt, trigger,
polarity);+}
Why does this take a pointer to the irq rather than returning the irq (as with irq_of_parse_and_map)?
This looks awfully generic. Are the timer interrupts encoded specially or is this useful for parsing other interrupts?
+static int __init acpi_parse_gtdt(struct acpi_table_header *table) +{
- struct acpi_table_gtdt *gtdt;
- gtdt = (struct acpi_table_gtdt *)table;
- if (!gtdt)
return -EINVAL;- arch_timer_rate = arch_timer_get_cntfrq();
- if (!arch_timer_rate) {
pr_warn("arch_timer: Could not get frequency from CNTFREG\n");
s/CNTFREG/CNTFREQ/
This is probably worth a pr_err at least, the system is unlikely to get very far if the timers don't work.
Thanks, Mark.