diff options
| -rw-r--r-- | drivers/net/ipa/ipa_clock.c | 71 | ||||
| -rw-r--r-- | drivers/net/ipa/ipa_clock.h | 18 | ||||
| -rw-r--r-- | drivers/net/ipa/ipa_modem.c | 7 |
3 files changed, 94 insertions, 2 deletions
diff --git a/drivers/net/ipa/ipa_clock.c b/drivers/net/ipa/ipa_clock.c index 8f25107c1f1e..74eb9ecdd19b 100644 --- a/drivers/net/ipa/ipa_clock.c +++ b/drivers/net/ipa/ipa_clock.c @@ -48,11 +48,15 @@ struct ipa_interconnect { * enum ipa_power_flag - IPA power flags * @IPA_POWER_FLAG_RESUMED: Whether resume from suspend has been signaled * @IPA_POWER_FLAG_SYSTEM: Hardware is system (not runtime) suspended + * @IPA_POWER_FLAG_STOPPED: Modem TX is disabled by ipa_start_xmit() + * @IPA_POWER_FLAG_STARTED: Modem TX was enabled by ipa_runtime_resume() * @IPA_POWER_FLAG_COUNT: Number of defined power flags */ enum ipa_power_flag { IPA_POWER_FLAG_RESUMED, IPA_POWER_FLAG_SYSTEM, + IPA_POWER_FLAG_STOPPED, + IPA_POWER_FLAG_STARTED, IPA_POWER_FLAG_COUNT, /* Last; not a flag */ }; @@ -60,6 +64,7 @@ enum ipa_power_flag { * struct ipa_clock - IPA clocking information * @dev: IPA device pointer * @core: IPA core clock + * @spinlock: Protects modem TX queue enable/disable * @flags: Boolean state flags * @interconnect_count: Number of elements in interconnect[] * @interconnect: Interconnect array @@ -67,6 +72,7 @@ enum ipa_power_flag { struct ipa_clock { struct device *dev; struct clk *core; + spinlock_t spinlock; /* used with STOPPED/STARTED power flags */ DECLARE_BITMAP(flags, IPA_POWER_FLAG_COUNT); u32 interconnect_count; struct ipa_interconnect *interconnect; @@ -334,6 +340,70 @@ static void ipa_suspend_handler(struct ipa *ipa, enum ipa_irq_id irq_id) ipa_interrupt_suspend_clear_all(ipa->interrupt); } +/* The next few functions coordinate stopping and starting the modem + * network device transmit queue. + * + * Transmit can be running concurrent with power resume, and there's a + * chance the resume completes before the transmit path stops the queue, + * leaving the queue in a stopped state. The next two functions are used + * to avoid this: ipa_power_modem_queue_stop() is used by ipa_start_xmit() + * to conditionally stop the TX queue; and ipa_power_modem_queue_start() + * is used by ipa_runtime_resume() to conditionally restart it. + * + * Two flags and a spinlock are used. If the queue is stopped, the STOPPED + * power flag is set. And if the queue is started, the STARTED flag is set. + * The queue is only started on resume if the STOPPED flag is set. And the + * queue is only started in ipa_start_xmit() if the STARTED flag is *not* + * set. As a result, the queue remains operational if the two activites + * happen concurrently regardless of the order they complete. The spinlock + * ensures the flag and TX queue operations are done atomically. + * + * The first function stops the modem netdev transmit queue, but only if + * the STARTED flag is *not* set. That flag is cleared if it was set. + * If the queue is stopped, the STOPPED flag is set. This is called only + * from the power ->runtime_resume operation. + */ +void ipa_power_modem_queue_stop(struct ipa *ipa) +{ + struct ipa_clock *clock = ipa->clock; + unsigned long flags; + + spin_lock_irqsave(&clock->spinlock, flags); + + if (!__test_and_clear_bit(IPA_POWER_FLAG_STARTED, clock->flags)) { + netif_stop_queue(ipa->modem_netdev); + __set_bit(IPA_POWER_FLAG_STOPPED, clock->flags); + } + + spin_unlock_irqrestore(&clock->spinlock, flags); +} + +/* This function starts the modem netdev transmit queue, but only if the + * STOPPED flag is set. That flag is cleared if it was set. If the queue + * was restarted, the STARTED flag is set; this allows ipa_start_xmit() + * to skip stopping the queue in the event of a race. + */ +void ipa_power_modem_queue_wake(struct ipa *ipa) +{ + struct ipa_clock *clock = ipa->clock; + unsigned long flags; + + spin_lock_irqsave(&clock->spinlock, flags); + + if (__test_and_clear_bit(IPA_POWER_FLAG_STOPPED, clock->flags)) { + __set_bit(IPA_POWER_FLAG_STARTED, clock->flags); + netif_wake_queue(ipa->modem_netdev); + } + + spin_unlock_irqrestore(&clock->spinlock, flags); +} + +/* This function clears the STARTED flag once the TX queue is operating */ +void ipa_power_modem_queue_active(struct ipa *ipa) +{ + clear_bit(IPA_POWER_FLAG_STARTED, ipa->clock->flags); +} + int ipa_power_setup(struct ipa *ipa) { int ret; @@ -383,6 +453,7 @@ ipa_clock_init(struct device *dev, const struct ipa_clock_data *data) } clock->dev = dev; clock->core = clk; + spin_lock_init(&clock->spinlock); clock->interconnect_count = data->interconnect_count; ret = ipa_interconnect_init(clock, dev, data->interconnect_data); diff --git a/drivers/net/ipa/ipa_clock.h b/drivers/net/ipa/ipa_clock.h index 5c53241336a1..64cd15981b1d 100644 --- a/drivers/net/ipa/ipa_clock.h +++ b/drivers/net/ipa/ipa_clock.h @@ -23,6 +23,24 @@ extern const struct dev_pm_ops ipa_pm_ops; u32 ipa_clock_rate(struct ipa *ipa); /** + * ipa_power_modem_queue_stop() - Possibly stop the modem netdev TX queue + * @ipa: IPA pointer + */ +void ipa_power_modem_queue_stop(struct ipa *ipa); + +/** + * ipa_power_modem_queue_wake() - Possibly wake the modem netdev TX queue + * @ipa: IPA pointer + */ +void ipa_power_modem_queue_wake(struct ipa *ipa); + +/** + * ipa_power_modem_queue_active() - Report modem netdev TX queue active + * @ipa: IPA pointer + */ +void ipa_power_modem_queue_active(struct ipa *ipa); + +/** * ipa_power_setup() - Set up IPA power management * @ipa: IPA pointer * diff --git a/drivers/net/ipa/ipa_modem.c b/drivers/net/ipa/ipa_modem.c index c8724af935b8..16d87910305e 100644 --- a/drivers/net/ipa/ipa_modem.c +++ b/drivers/net/ipa/ipa_modem.c @@ -130,6 +130,7 @@ ipa_start_xmit(struct sk_buff *skb, struct net_device *netdev) if (ret < 1) { /* If a resume won't happen, just drop the packet */ if (ret < 0 && ret != -EINPROGRESS) { + ipa_power_modem_queue_active(ipa); pm_runtime_put_noidle(dev); goto err_drop_skb; } @@ -138,13 +139,15 @@ ipa_start_xmit(struct sk_buff *skb, struct net_device *netdev) * until we're resumed; ipa_modem_resume() arranges for the * TX queue to be started again. */ - netif_stop_queue(netdev); + ipa_power_modem_queue_stop(ipa); (void)pm_runtime_put(dev); return NETDEV_TX_BUSY; } + ipa_power_modem_queue_active(ipa); + ret = ipa_endpoint_skb_tx(endpoint, skb); (void)pm_runtime_put(dev); @@ -241,7 +244,7 @@ static void ipa_modem_wake_queue_work(struct work_struct *work) { struct ipa_priv *priv = container_of(work, struct ipa_priv, work); - netif_wake_queue(priv->ipa->modem_netdev); + ipa_power_modem_queue_wake(priv->ipa); } /** ipa_modem_resume() - resume callback for runtime_pm |