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Commit cfe319dd authored by Naveen Kaje's avatar Naveen Kaje
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msm_serial_hs: wait for clock-off to complete before shutdown 



Make sure clock-off request completes before closing the port to
avoid unclocked hardware access.

CRs-Fixed: 648827
Change-Id: I953a06c104830c5515551d5edc4dd9c9a037203f
Signed-off-by: default avatarNaveen Kaje <nkaje@codeaurora.org>
parent 760e6e62

drivers/tty/serial/msm_serial_hs.c

+45 −18
Original line number Diff line number Diff line
@@ -336,6 +336,7 @@ static int msm_hs_clock_vote(struct msm_hs_port *msm_uport) 
{

	int rc = 0;



	mutex_lock(&msm_uport->clk_mutex);

	if (1 == atomic_inc_return(&msm_uport->clk_count)) {

		msm_hs_bus_voting(msm_uport, BUS_SCALING);

		/* Turn on core clk and iface clk */
@@ -345,6 +346,7 @@ static int msm_hs_clock_vote(struct msm_hs_port *msm_uport) 
				dev_err(msm_uport->uport.dev,

					"%s: Could not turn on pclk [%d]\n",

					__func__, rc);

				mutex_unlock(&msm_uport->clk_mutex);

				return rc;

			}

		}
@@ -355,11 +357,13 @@ static int msm_hs_clock_vote(struct msm_hs_port *msm_uport) 
				"%s: Could not turn on core clk [%d]\n",

				__func__, rc);

			clk_disable_unprepare(msm_uport->pclk);

			mutex_unlock(&msm_uport->clk_mutex);

			return rc;

		}

		msm_uport->clk_state = MSM_HS_CLK_ON;

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

	}

	mutex_unlock(&msm_uport->clk_mutex);





	return rc;
@@ -376,6 +380,7 @@ static void msm_hs_clock_unvote(struct msm_hs_port *msm_uport) 
		return;

	}



	mutex_lock(&msm_uport->clk_mutex);

	rc = atomic_dec_return(&msm_uport->clk_count);

	if (0 == rc) {

		/* Turn off the core clk and iface clk*/
@@ -387,6 +392,7 @@ static void msm_hs_clock_unvote(struct msm_hs_port *msm_uport) 
		msm_uport->clk_state = MSM_HS_CLK_OFF;

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

	}

	mutex_unlock(&msm_uport->clk_mutex);

}



/* Check if the uport line number matches with user id stored in pdata.
@@ -1821,8 +1827,6 @@ static int msm_hs_check_clock_off(struct uart_port *uport) 
	if (msm_uport->clk_state != MSM_HS_CLK_REQUEST_OFF ||

	    !uart_circ_empty(tx_buf) || msm_uport->tx.dma_in_flight ||

	    msm_uport->imr_reg & UARTDM_ISR_TXLEV_BMSK) {

		spin_unlock_irqrestore(&uport->lock, flags);

		mutex_unlock(&msm_uport->clk_mutex);

		if (msm_uport->clk_state == MSM_HS_CLK_REQUEST_OFF) {

			msm_uport->clk_state = MSM_HS_CLK_ON;

			/* Pulling RFR line high */
@@ -1833,6 +1837,8 @@ static int msm_hs_check_clock_off(struct uart_port *uport) 
			msm_hs_write(uport, UART_DM_MR1, data);

			mb();

		}

		spin_unlock_irqrestore(&uport->lock, flags);

		mutex_unlock(&msm_uport->clk_mutex);

		MSM_HS_DBG("%s(): clkstate %d", __func__, msm_uport->clk_state);

		return -1;

	}
@@ -1870,7 +1876,9 @@ static int msm_hs_check_clock_off(struct uart_port *uport) 
	mb();



	/* we really want to clock off */

	mutex_unlock(&msm_uport->clk_mutex);

	msm_hs_clock_unvote(msm_uport);

	mutex_lock(&msm_uport->clk_mutex);



	spin_lock_irqsave(&uport->lock, flags);

	if (use_low_power_wakeup(msm_uport)) {
@@ -2091,7 +2099,9 @@ void msm_hs_request_clock_on(struct uart_port *uport) 
		}

		spin_unlock_irqrestore(&uport->lock, flags);



		mutex_unlock(&msm_uport->clk_mutex);

		ret = msm_hs_clock_vote(msm_uport);

		mutex_lock(&msm_uport->clk_mutex);

		if (ret) {

			MSM_HS_INFO("Clock ON Failure"

			"For UART CLK Stalling HSUART\n");
@@ -2106,8 +2116,10 @@ void msm_hs_request_clock_on(struct uart_port *uport) 
			spin_unlock_irqrestore(&uport->lock, flags);

			MSM_HS_DBG("%s:Calling wait forxcompletion\n",

					__func__);

			mutex_unlock(&msm_uport->clk_mutex);

			ret = wait_event_timeout(msm_uport->bam_disconnect_wait,

				msm_uport->rx.flush == FLUSH_SHUTDOWN, 300);

			mutex_lock(&msm_uport->clk_mutex);

			if (!ret)

				MSM_HS_ERR("BAM Disconnect not happened\n");

			spin_lock_irqsave(&uport->lock, flags);
@@ -3180,8 +3192,25 @@ static void msm_hs_shutdown(struct uart_port *uport) 
	struct msm_hs_tx *tx = &msm_uport->tx;

	struct sps_pipe *sps_pipe_handle = tx->cons.pipe_handle;



	MSM_HS_INFO("%s()\n", __func__);

	msm_hs_clock_vote(msm_uport);

	/*

	 * cancel the hrtimer first so that

	 * clk_state can not change in flight

	 */

	hrtimer_cancel(&msm_uport->clk_off_timer);

	flush_work(&msm_uport->clock_off_w);



	if (use_low_power_wakeup(msm_uport))

		irq_set_irq_wake(msm_uport->wakeup.irq, 0);



	/* wake irq or uart irq is active depending on clk_state */

	if (msm_uport->clk_state == MSM_HS_CLK_OFF) {

		if (use_low_power_wakeup(msm_uport))

			disable_irq(msm_uport->wakeup.irq);

	} else {

		disable_irq(uport->irq);

		wake_unlock(&msm_uport->dma_wake_lock);

	}



	/* make sure tx tasklet finishes */

	tasklet_kill(&msm_uport->tx.tlet);

	ret = wait_event_timeout(msm_uport->tx.wait,
@@ -3189,21 +3218,20 @@ static void msm_hs_shutdown(struct uart_port *uport) 
	if (!ret)

		MSM_HS_WARN("Shutdown called when tx buff not empty");



	/* BAM Disconnect for TX */

	ret = sps_disconnect(sps_pipe_handle);

	if (ret)

		MSM_HS_ERR("%s(): sps_disconnect failed\n",

					__func__);

	/* make sure rx tasklet finishes */

	tasklet_kill(&msm_uport->rx.tlet);

	wait_event(msm_uport->rx.wait, msm_uport->rx.flush == FLUSH_SHUTDOWN);

	cancel_delayed_work_sync(&msm_uport->rx.flip_insert_work);

	flush_workqueue(msm_uport->hsuart_wq);

	WARN_ON(msm_uport->rx.flush < FLUSH_STOP);

	pm_runtime_disable(uport->dev);

	msm_uport->rx.buffer_pending = NONE_PENDING;

	MSM_HS_DBG("%s(): tx, rx events complete", __func__);



	msm_hs_clock_vote(msm_uport);

	mutex_lock(&msm_uport->clk_mutex);

	/* BAM Disconnect for TX */

	ret = sps_disconnect(sps_pipe_handle);

	if (ret)

		MSM_HS_ERR("%s(): sps_disconnect failed\n",

					__func__);

	WARN_ON(msm_uport->rx.flush < FLUSH_STOP);

	/* Disable the transmitter */

	msm_hs_write(uport, UART_DM_CR, UARTDM_CR_TX_DISABLE_BMSK);

	/* Disable the receiver */
@@ -3216,22 +3244,21 @@ static void msm_hs_shutdown(struct uart_port *uport) 
	 * Hence mb() requires here.

	 */

	mb();

	mutex_unlock(&msm_uport->clk_mutex);



	hrtimer_cancel(&msm_uport->clk_off_timer);

	msm_uport->rx.buffer_pending = NONE_PENDING;

	MSM_HS_DBG("%s(): tx, rx events complete", __func__);

	msm_hs_clock_unvote(msm_uport);

	if (msm_uport->clk_state != MSM_HS_CLK_OFF) {

		/* to balance clk_state */

		msm_hs_clock_unvote(msm_uport);

		wake_unlock(&msm_uport->dma_wake_lock);

	}



	pm_runtime_disable(uport->dev);

	msm_uport->clk_state = MSM_HS_CLK_PORT_OFF;

	dma_unmap_single(uport->dev, msm_uport->tx.dma_base,

			 UART_XMIT_SIZE, DMA_TO_DEVICE);



	if (use_low_power_wakeup(msm_uport))

		irq_set_irq_wake(msm_uport->wakeup.irq, 0);



	/* Free the interrupt */

	free_irq(uport->irq, msm_uport);

	if (use_low_power_wakeup(msm_uport))