powernv/opal: Notifier for OPAL events
This patch implements a notifier to receive a notification on OPAL event mask changes. The notifier is only called as a result of an OPAL interrupt, which will happen upon reception of FSP messages or PCI errors. Any event mask change detected as a result of opal_poll_events() will not result in a notifier call. [benh: changelog] Signed-off-by: Gavin Shan <shangw@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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@ -644,6 +644,11 @@ extern void hvc_opal_init_early(void);
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extern int early_init_dt_scan_opal(unsigned long node, const char *uname,
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int depth, void *data);
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extern int opal_notifier_register(struct notifier_block *nb);
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extern void opal_notifier_enable(void);
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extern void opal_notifier_disable(void);
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extern void opal_notifier_update_evt(uint64_t evt_mask, uint64_t evt_val);
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extern int opal_get_chars(uint32_t vtermno, char *buf, int count);
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extern int opal_put_chars(uint32_t vtermno, const char *buf, int total_len);
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@ -15,6 +15,7 @@
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#include <linux/of.h>
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#include <linux/of_platform.h>
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#include <linux/interrupt.h>
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#include <linux/notifier.h>
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#include <linux/slab.h>
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#include <asm/opal.h>
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#include <asm/firmware.h>
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@ -31,6 +32,10 @@ static DEFINE_SPINLOCK(opal_write_lock);
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extern u64 opal_mc_secondary_handler[];
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static unsigned int *opal_irqs;
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static unsigned int opal_irq_count;
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static ATOMIC_NOTIFIER_HEAD(opal_notifier_head);
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static DEFINE_SPINLOCK(opal_notifier_lock);
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static uint64_t last_notified_mask = 0x0ul;
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static atomic_t opal_notifier_hold = ATOMIC_INIT(0);
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int __init early_init_dt_scan_opal(unsigned long node,
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const char *uname, int depth, void *data)
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@ -95,6 +100,68 @@ static int __init opal_register_exception_handlers(void)
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early_initcall(opal_register_exception_handlers);
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int opal_notifier_register(struct notifier_block *nb)
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{
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if (!nb) {
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pr_warning("%s: Invalid argument (%p)\n",
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__func__, nb);
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return -EINVAL;
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}
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atomic_notifier_chain_register(&opal_notifier_head, nb);
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return 0;
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}
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static void opal_do_notifier(uint64_t events)
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{
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unsigned long flags;
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uint64_t changed_mask;
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if (atomic_read(&opal_notifier_hold))
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return;
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spin_lock_irqsave(&opal_notifier_lock, flags);
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changed_mask = last_notified_mask ^ events;
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last_notified_mask = events;
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spin_unlock_irqrestore(&opal_notifier_lock, flags);
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/*
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* We feed with the event bits and changed bits for
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* enough information to the callback.
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*/
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atomic_notifier_call_chain(&opal_notifier_head,
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events, (void *)changed_mask);
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}
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void opal_notifier_update_evt(uint64_t evt_mask,
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uint64_t evt_val)
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{
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unsigned long flags;
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spin_lock_irqsave(&opal_notifier_lock, flags);
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last_notified_mask &= ~evt_mask;
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last_notified_mask |= evt_val;
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spin_unlock_irqrestore(&opal_notifier_lock, flags);
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}
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void opal_notifier_enable(void)
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{
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int64_t rc;
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uint64_t evt = 0;
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atomic_set(&opal_notifier_hold, 0);
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/* Process pending events */
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rc = opal_poll_events(&evt);
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if (rc == OPAL_SUCCESS && evt)
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opal_do_notifier(evt);
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}
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void opal_notifier_disable(void)
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{
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atomic_set(&opal_notifier_hold, 1);
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}
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int opal_get_chars(uint32_t vtermno, char *buf, int count)
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{
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s64 len, rc;
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@ -297,7 +364,7 @@ static irqreturn_t opal_interrupt(int irq, void *data)
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opal_handle_interrupt(virq_to_hw(irq), &events);
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/* XXX TODO: Do something with the events */
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opal_do_notifier(events);
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return IRQ_HANDLED;
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}
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