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Commit 4502b6bb authored by Fu Wei's avatar Fu Wei Committed by Mark Rutland
Browse files

clocksource: arm_arch_timer: rework PPI selection 



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: default avatarFu Wei <fu.wei@linaro.org>
Tested-by: default avatarXiongfeng Wang <wangxiongfeng2@huawei.com>
[Mark: reword commit message]
Signed-off-by: default avatarMark Rutland <mark.rutland@arm.com>
parent 097cd143

drivers/clocksource/arm_arch_timer.c

+46 −31
Original line number Diff line number Diff line
@@ -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);
@@ -1114,40 +1114,42 @@ static int __init arch_timer_common_init(void) 
	return arch_timer_arch_init();

}



static int __init arch_timer_init(void)

{

	int ret;

	/*

/**

 * 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.

 *

	 * 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 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.

 */

	if (is_hyp_mode_available() || !arch_timer_ppi[ARCH_TIMER_VIRT_PPI]) {

		bool has_ppi;

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_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 (!is_hyp_mode_available() && arch_timer_ppi[ARCH_TIMER_VIRT_PPI])

		return ARCH_TIMER_VIRT_PPI;



		if (!has_ppi) {

			pr_warn("No interrupt available, giving up\n");

			return -EINVAL;

		}

	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;



	ret = arch_timer_register();

	if (ret)

		return 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);