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Subject[PATCH 5/5] irqchip: gicv3-its: add support for power down
Date
Configurations of an ITS cannot be changed if the ITS is in an
active status, so it might not be safe to perform a soft reboot
with all the active ITSes un-disabled, etc. kexec.

This patch will make sure all the active ITSes disabled before
enabling them again without resetting ITS hardware.

Signed-off-by: Yun Wu <wuyun.wu@huawei.com>
---
drivers/irqchip/irq-gic-v3-its.c | 59 ++++++++++++++++++++++++++++++++++++++++
1 file changed, 59 insertions(+)

diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
index facf6d6..1d85471 100644
--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -29,6 +29,7 @@
#include <linux/of_platform.h>
#include <linux/percpu.h>
#include <linux/slab.h>
+#include <linux/reboot.h>

#include <linux/irqchip/arm-gic-v3.h>

@@ -1410,6 +1411,63 @@ int its_cpu_init(void)
return 0;
}

+static void its_disable(struct its_node *its)
+{
+ u32 count = 1000000; /* 1s */
+ u32 val;
+
+ /* Disable the generation of all interrupts to this ITS */
+ val = readl_relaxed(its->base + GITS_CTLR);
+ val &= ~GITS_CTLR_ENABLE;
+ writel_relaxed(val, its->base + GITS_CTLR);
+
+ /* Poll GITS_CTLR and wait until ITS becomes quiescent */
+ while (count--) {
+ val = readl_relaxed(its->base + GITS_CTLR);
+ if (val & GITS_CTLR_QUIESCENT)
+ break;
+ cpu_relax();
+ udelay(1);
+ }
+
+ if (!count)
+ pr_err("%s: failed to shutdown!\n",
+ its->msi_chip.of_node->full_name);
+
+ /*
+ * Release all resources of this ITS node to completely put
+ * an end to it. Note that this step may not be necessary
+ * in some cases, but leaving it here does no harm.
+ */
+ irq_domain_remove(its->msi_chip.domain);
+ irq_domain_remove(its->domain);
+ its_free_tables(its);
+ kfree(its->cmd_base);
+ iounmap(its->base);
+
+ spin_lock(&its_lock);
+ list_del(&its->entry);
+ spin_unlock(&its_lock);
+ kfree(its);
+}
+
+static int its_shutdown(struct notifier_block *nfb, unsigned long val, void *v)
+{
+ struct its_node *its, *tmp;
+
+ list_for_each_entry_safe(its, tmp, &its_nodes, entry)
+ its_disable(its);
+
+ kfree(gic_rdists->prop_page);
+ kfree(lpi_bitmap);
+
+ return NOTIFY_OK;
+}
+
+static struct notifier_block its_reboot_notifier = {
+ .notifier_call = its_shutdown,
+};
+
static struct of_device_id its_device_id[] = {
{ .compatible = "arm,gic-v3-its", },
{},
@@ -1435,6 +1493,7 @@ int its_init(struct device_node *node, struct rdists *rdists,

its_alloc_lpi_tables();
its_lpi_init(rdists->id_bits);
+ register_reboot_notifier(&its_reboot_notifier);

return 0;
}
--
1.8.0



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