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clocksource: arm_arch_timer: rework PPI selection

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Currently, the arch timer driver uses ARCH_TIMER_PHYS_SECURE_PPI to mean
the driver will use the secure PPI *and* potentially also use the
non-secure PPI. This is somewhat confusing.

For arm64 it never makes sense to use the secure PPI, but we do anyway,
inheriting this behaviour from 32-bit arm. For ACPI, we may not even
have a valid secure PPI, so we need to be able to only request the
non-secure PPI.

To that end, this patch reworks the timer driver so that we can request
the non-secure PPI alone. The PPI selection is split out into a new
function, arch_timer_select_ppi(), and verification of the selected PPI
is shifted out to callers (as DT may select the PPI by other means and
must handle this anyway).

We now consistently use arch_timer_has_nonsecure_ppi() to determine
whether we must manage a non-secure PPI *in addition* to a secure PPI.
When we only have a non-secure PPI, this returns false.

Signed-off-by: Fu Wei <fu.wei@linaro.org>
Tested-by: Xiongfeng Wang <wangxiongfeng2@huawei.com>
[Mark: reword commit message]
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
This commit is contained in:
Fu Wei 2017-01-18 21:25:30 +08:00 committed by Mark Rutland
parent 097cd143dd
commit 4502b6bb72
1 changed files with 46 additions and 31 deletions
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77
drivers/clocksource/arm_arch_timer.c
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@ -992,7 +992,7 @@ static int __init arch_timer_register(void)
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[ARCH_TIMER_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);
@ -1114,39 +1114,41 @@ static int __init arch_timer_common_init(void)
return arch_timer_arch_init();
}
/**
* 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)
{
if (is_kernel_in_hyp_mode())
return ARCH_TIMER_HYP_PPI;
if (!is_hyp_mode_available() && arch_timer_ppi[ARCH_TIMER_VIRT_PPI])
return ARCH_TIMER_VIRT_PPI;
if (IS_ENABLED(CONFIG_ARM64))
return ARCH_TIMER_PHYS_NONSECURE_PPI;
return ARCH_TIMER_PHYS_SECURE_PPI;
}
static int __init arch_timer_init(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[ARCH_TIMER_VIRT_PPI]) {
bool has_ppi;
if (is_kernel_in_hyp_mode()) {
arch_timer_uses_ppi = ARCH_TIMER_HYP_PPI;
has_ppi = !!arch_timer_ppi[ARCH_TIMER_HYP_PPI];
} else {
arch_timer_uses_ppi = ARCH_TIMER_PHYS_SECURE_PPI;
has_ppi = (!!arch_timer_ppi[ARCH_TIMER_PHYS_SECURE_PPI] ||
!!arch_timer_ppi[ARCH_TIMER_PHYS_NONSECURE_PPI]);
}
if (!has_ppi) {
pr_warn("No interrupt available, giving up\n");
return -EINVAL;
}
}
ret = arch_timer_register();
if (ret)
@ -1188,6 +1190,13 @@ 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 = 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,
@ -1333,6 +1342,12 @@ static int __init arch_timer_acpi_init(struct acpi_table_header *table)
/* 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);