[PATCH v10 5/7] drivers: firmware: psci: initialise idle states using ACPI LPI

Sudeep Holla
2016-07-19T17:52:57Z

This patch adds support for initialisation of PSCI CPUIdle states
from Low Power Idle(_LPI) entries in the ACPI tables when acpi is
enabled.

Cc: Mark Rutland <mark.rutland@arm.com>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Acked-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
---
drivers/firmware/psci.c | 66 +++++++++++++++++++++++++++++++++++++++++++------
1 file changed, 59 insertions(+), 7 deletions(-)

diff --git a/drivers/firmware/psci.c b/drivers/firmware/psci.c
index 03e04582791c..8263429e21b8 100644
--- a/drivers/firmware/psci.c
+++ b/drivers/firmware/psci.c
@@ -13,6 +13,7 @@

#define pr_fmt(fmt) "psci: " fmt

+#include <linux/acpi.h>
#include <linux/arm-smccc.h>
#include <linux/cpuidle.h>
#include <linux/errno.h>
@@ -256,13 +257,6 @@ static int psci_dt_cpu_init_idle(struct device_node *cpu_node, int cpu)
u32 *psci_states;
struct device_node *state_node;

- /*
- * If the PSCI cpu_suspend function hook has not been initialized
- * idle states must not be enabled, so bail out
- */
- if (!psci_ops.cpu_suspend)
- return -EOPNOTSUPP;
-
/* Count idle states */
while ((state_node = of_parse_phandle(cpu_node, "cpu-idle-states",
count))) {
@@ -310,11 +304,69 @@ static int psci_dt_cpu_init_idle(struct device_node *cpu_node, int cpu)
return ret;
}

+#ifdef CONFIG_ACPI
+#include <acpi/processor.h>
+
+static int __maybe_unused psci_acpi_cpu_init_idle(unsigned int cpu)
+{
+ int i, count;
+ u32 *psci_states;
+ struct acpi_lpi_state *lpi;
+ struct acpi_processor *pr = per_cpu(processors, cpu);
+
+ if (unlikely(!pr || !pr->flags.has_lpi))
+ return -EINVAL;
+
+ count = pr->power.count - 1;
+ if (count <= 0)
+ return -ENODEV;
+
+ psci_states = kcalloc(count, sizeof(*psci_states), GFP_KERNEL);
+ if (!psci_states)
+ return -ENOMEM;
+
+ for (i = 0; i < count; i++) {
+ u32 state;
+
+ lpi = &pr->power.lpi_states[i + 1];
+ /*
+ * Only bits[31:0] represent a PSCI power_state while
+ * bits[63:32] must be 0x0 as per ARM ACPI FFH Specification
+ */
+ state = lpi->address;
+ if (!psci_power_state_is_valid(state)) {
+ pr_warn("Invalid PSCI power state %#x\n", state);
+ kfree(psci_states);
+ return -EINVAL;
+ }
+ psci_states[i] = state;
+ }
+ /* Idle states parsed correctly, initialize per-cpu pointer */
+ per_cpu(psci_power_state, cpu) = psci_states;
+ return 0;
+}
+#else
+static int __maybe_unused psci_acpi_cpu_init_idle(unsigned int cpu)
+{
+ return -EINVAL;
+}
+#endif
+
int psci_cpu_init_idle(unsigned int cpu)
{
struct device_node *cpu_node;
int ret;

+ /*
+ * If the PSCI cpu_suspend function hook has not been initialized
+ * idle states must not be enabled, so bail out
+ */
+ if (!psci_ops.cpu_suspend)
+ return -EOPNOTSUPP;
+
+ if (!acpi_disabled)
+ return psci_acpi_cpu_init_idle(cpu);
+
cpu_node = of_get_cpu_node(cpu, NULL);
if (!cpu_node)
return -ENODEV;
--
2.7.4