Merge "msm: bam_dmux: Fix race condition during SSR" (ef5c35bd) · Commits · e / devices / android_kernel_sony_msm8994

arch/arm/mach-msm/bam_dmux.c

+23 −2

Original line number	Diff line number	Diff line
		@@ -29,6 +29,7 @@
		#include <linux/kfifo.h>
		#include <linux/of.h>
		#include <linux/ipc_logging.h>
		#include <linux/srcu.h>
		#include <mach/sps.h>
		#include <mach/bam_dmux.h>
		#include <mach/msm_smsm.h>
		@@ -222,6 +223,8 @@ static struct delayed_work queue_rx_work;
		static struct workqueue_struct *bam_mux_rx_workqueue;
		static struct workqueue_struct *bam_mux_tx_workqueue;

		static struct srcu_struct bam_dmux_srcu;

		/* A2 power collaspe */
		#define UL_TIMEOUT_DELAY 1000 /* in ms */
		#define ENABLE_DISCONNECT_ACK 0x1
		@@ -739,6 +742,7 @@ int msm_bam_dmux_write(uint32_t id, struct sk_buff *skb)
		struct sk_buff *new_skb = NULL;
		dma_addr_t dma_address;
		struct tx_pkt_info *pkt;
		int rcu_id;

		if (id >= BAM_DMUX_NUM_CHANNELS)
		return -EINVAL;
		@@ -747,11 +751,19 @@ int msm_bam_dmux_write(uint32_t id, struct sk_buff *skb)
		if (!bam_mux_initialized)
		return -ENODEV;

		rcu_id = srcu_read_lock(&bam_dmux_srcu);
		if (in_global_reset) {
		BAM_DMUX_LOG("%s: In SSR... ch_id[%d]\n", __func__, id);
		srcu_read_unlock(&bam_dmux_srcu, rcu_id);
		return -EFAULT;
		}

		DBG("%s: writing to ch %d len %d\n", __func__, id, skb->len);
		spin_lock_irqsave(&bam_ch[id].lock, flags);
		if (!bam_ch_is_open(id)) {
		spin_unlock_irqrestore(&bam_ch[id].lock, flags);
		pr_err("%s: port not open: %d\n", __func__, bam_ch[id].status);
		srcu_read_unlock(&bam_dmux_srcu, rcu_id);
		return -ENODEV;
		}

		@@ -759,6 +771,7 @@ int msm_bam_dmux_write(uint32_t id, struct sk_buff *skb)
		(bam_ch[id].num_tx_pkts >= HIGH_WATERMARK)) {
		spin_unlock_irqrestore(&bam_ch[id].lock, flags);
		pr_err("%s: watermark exceeded: %d\n", __func__, id);
		srcu_read_unlock(&bam_dmux_srcu, rcu_id);
		return -EAGAIN;
		}
		spin_unlock_irqrestore(&bam_ch[id].lock, flags);
		@@ -767,8 +780,10 @@ int msm_bam_dmux_write(uint32_t id, struct sk_buff *skb)
		if (!bam_is_connected) {
		read_unlock(&ul_wakeup_lock);
		ul_wakeup();
		if (unlikely(in_global_reset == 1))
		if (unlikely(in_global_reset == 1)) {
		srcu_read_unlock(&bam_dmux_srcu, rcu_id);
		return -EFAULT;
		}
		read_lock(&ul_wakeup_lock);
		notify_all(BAM_DMUX_UL_CONNECTED, (unsigned long)(NULL));
		}
		@@ -846,6 +861,7 @@ int msm_bam_dmux_write(uint32_t id, struct sk_buff *skb)
		}
		ul_packet_written = 1;
		read_unlock(&ul_wakeup_lock);
		srcu_read_unlock(&bam_dmux_srcu, rcu_id);
		return rc;

		write_fail3:
		@@ -856,6 +872,7 @@ write_fail2:
		dev_kfree_skb_any(new_skb);
		write_fail:
		read_unlock(&ul_wakeup_lock);
		srcu_read_unlock(&bam_dmux_srcu, rcu_id);
		return -ENOMEM;
		}

		@@ -1956,9 +1973,12 @@ static int restart_notifier_cb(struct notifier_block *this,
		* because a watchdog crash from a bus stall would likely occur.
		*/
		if (code == SUBSYS_BEFORE_SHUTDOWN) {
		BAM_DMUX_LOG("%s: begin\n", __func__);
		in_global_reset = 1;
		in_ssr = 1;
		BAM_DMUX_LOG("%s: begin\n", __func__);
		/* wait till all bam_dmux writes completes */
		synchronize_srcu(&bam_dmux_srcu);
		BAM_DMUX_LOG("%s: ssr signaling complete\n", __func__);
		flush_workqueue(bam_mux_rx_workqueue);
		}
		if (code != SUBSYS_AFTER_SHUTDOWN)
		@@ -2478,6 +2498,7 @@ static int bam_dmux_probe(struct platform_device *pdev)
		INIT_DELAYED_WORK(&ul_timeout_work, ul_timeout);
		INIT_DELAYED_WORK(&queue_rx_work, queue_rx_work_func);
		wake_lock_init(&bam_wakelock, WAKE_LOCK_SUSPEND, "bam_dmux_wakelock");
		init_srcu_struct(&bam_dmux_srcu);

		rc = bam_ops->smsm_state_cb_register_ptr(SMSM_MODEM_STATE,
		SMSM_A2_POWER_CONTROL,