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Commit f6121889 authored by Girish Mahadevan's avatar Girish Mahadevan
Browse files

serial: msm_serial_hs: Move clk count voting out of runtime callbacks 



Don't modify the ref count variable clk count inside the runtime callbacks.
Doing so could result in a case where the driver might end up calling a put
twice on the runtime object. The resulting imbalance will leave the runtime
state for the device in a bad state.

Change-Id: I34989768811b23762c4afe3e33e229ffa3f1db17
Signed-off-by: default avatarGirish Mahadevan <girishm@codeaurora.org>
parent 0c3a23a4

drivers/tty/serial/msm_serial_hs.c

+9 −9
Original line number Diff line number Diff line
@@ -214,7 +214,7 @@ struct msm_hs_port { 
	struct clk *pclk;

	struct msm_hs_tx tx;

	struct msm_hs_rx rx;

	atomic_t clk_count;

	atomic_t resource_count;

	struct msm_hs_wakeup wakeup;



	struct dentry *loopback_dir;
@@ -353,7 +353,6 @@ static int msm_hs_clk_bus_vote(struct msm_hs_port *msm_uport) 
			__func__, rc);

		goto core_unprepare;

	}

	atomic_inc(&msm_uport->clk_count);

	MSM_HS_DBG("%s: Clock ON successful\n", __func__);

	return rc;

core_unprepare:
@@ -374,7 +373,6 @@ static void msm_hs_clk_bus_unvote(struct msm_hs_port *msm_uport) 
	if (msm_uport->pclk)

		clk_disable_unprepare(msm_uport->pclk);

	msm_hs_bus_voting(msm_uport, BUS_RESET);

	atomic_dec(&msm_uport->clk_count);

	MSM_HS_DBG("%s: Clock OFF successful\n", __func__);

}
@@ -382,7 +380,7 @@ static void msm_hs_clk_bus_unvote(struct msm_hs_port *msm_uport) 
static void msm_hs_resource_unvote(struct msm_hs_port *msm_uport)

{

	struct uart_port *uport = &(msm_uport->uport);

	int rc = atomic_read(&msm_uport->clk_count);

	int rc = atomic_read(&msm_uport->resource_count);



	MSM_HS_DBG("%s(): power usage count %d", __func__, rc);

	if (rc <= 0) {
@@ -390,6 +388,7 @@ static void msm_hs_resource_unvote(struct msm_hs_port *msm_uport) 
		WARN_ON(1);

		return;

	}

	atomic_dec(&msm_uport->resource_count);

	pm_runtime_mark_last_busy(uport->dev);

	pm_runtime_put_autosuspend(uport->dev);

}
@@ -405,6 +404,7 @@ static void msm_hs_resource_vote(struct msm_hs_port *msm_uport) 
			__func__, uport->dev, ret);

		msm_hs_pm_resume(uport->dev);

	}

	atomic_inc(&msm_uport->resource_count);

}



/* Check if the uport line number matches with user id stored in pdata.
@@ -593,8 +593,8 @@ static void dump_uart_hs_registers(struct msm_hs_port *msm_uport) 
	struct uart_port *uport = &(msm_uport->uport);



	if (msm_uport->pm_state != MSM_HS_PM_ACTIVE) {

		MSM_HS_INFO("%s:Failed clocks are off, clk_count %d",

			__func__, atomic_read(&msm_uport->clk_count));

		MSM_HS_INFO("%s:Failed clocks are off, resource_count %d",

			__func__, atomic_read(&msm_uport->resource_count));

		return;

	}
@@ -3206,7 +3206,7 @@ static int msm_hs_pm_sys_suspend_noirq(struct device *dev) 
	 * If there is an active clk request or an impending userspace request

	 * fail the suspend callback.

	 */

	clk_cnt = atomic_read(&msm_uport->clk_count);

	clk_cnt = atomic_read(&msm_uport->resource_count);

	client_count = atomic_read(&msm_uport->client_count);

	if (msm_uport->pm_state == MSM_HS_PM_ACTIVE) {

		MSM_HS_WARN("%s:Fail Suspend.clk_cnt:%d,clnt_count:%d\n",
@@ -3652,9 +3652,9 @@ static void msm_hs_shutdown(struct uart_port *uport) 
			 UART_XMIT_SIZE, DMA_TO_DEVICE);



	msm_hs_resource_unvote(msm_uport);

	rc = atomic_read(&msm_uport->clk_count);

	rc = atomic_read(&msm_uport->resource_count);

	if (rc) {

		atomic_set(&msm_uport->clk_count, 1);

		atomic_set(&msm_uport->resource_count, 1);

		MSM_HS_WARN("%s(): removing extra vote\n", __func__);

		msm_hs_resource_unvote(msm_uport);

	}