serial: 8250: omap: Fix imprecise external abort for omap_8250_pm()
We must idle the uart only after serial8250_unregister_port(). Otherwise unbinding the uart via sysfs while doing cat on the port produces an imprecise external abort: mem_serial_in from omap_8250_pm+0x44/0xf4 omap_8250_pm from uart_hangup+0xe0/0x194 uart_hangup from __tty_hangup.part.0+0x37c/0x3a8 __tty_hangup.part.0 from uart_remove_one_port+0x9c/0x22c uart_remove_one_port from serial8250_unregister_port+0x60/0xe8 serial8250_unregister_port from omap8250_remove+0x6c/0xd0 omap8250_remove from platform_remove+0x28/0x54 Turns out the driver needs to have runtime PM functional before the driver probe calls serial8250_register_8250_port(). And it needs runtime PM after driver remove calls serial8250_unregister_port(). On probe, we need to read registers before registering the port in omap_serial_fill_features_erratas(). We do that with custom uart_read() already. On remove, after serial8250_unregister_port(), we need to write to the uart registers to idle the device. Let's add a custom uart_write() for that. Currently the uart register access depends on port->membase to be initialized, which won't work after serial8250_unregister_port(). Let's use priv->membase instead, and use it for runtime PM related functions to remove the dependency to port->membase for early and late register access. Note that during use, we need to check for a valid port in the runtime PM related functions. This is needed for the optional wakeup configuration. We now need to set the drvdata a bit earlier so it's available for the runtime PM functions. With the port checks in runtime PM functions, the old checks for priv in omap8250_runtime_suspend() and omap8250_runtime_resume() functions are no longer needed and are removed. Signed-off-by: Tony Lindgren <tony@atomide.com> Link: https://lore.kernel.org/r/20230508082014.23083-3-tony@atomide.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Tony Lindgren
Greg Kroah-Hartman
Родитель
b9ab22c2bc
Коммит
398cecc248
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@ -32,6 +32,7 @@
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#include "8250.h"
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#define DEFAULT_CLK_SPEED 48000000
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#define OMAP_UART_REGSHIFT 2
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#define UART_ERRATA_i202_MDR1_ACCESS (1 << 0)
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#define OMAP_UART_WER_HAS_TX_WAKEUP (1 << 1)
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@ -115,6 +116,7 @@
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#define UART_OMAP_RX_LVL 0x19
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struct omap8250_priv {
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void __iomem *membase;
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int line;
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u8 habit;
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u8 mdr1;
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@ -159,9 +161,14 @@ static void omap_8250_rx_dma_flush(struct uart_8250_port *p);
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static inline void omap_8250_rx_dma_flush(struct uart_8250_port *p) { }
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#endif
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static u32 uart_read(struct uart_8250_port *up, u32 reg)
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static u32 uart_read(struct omap8250_priv *priv, u32 reg)
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{
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return readl(up->port.membase + (reg << up->port.regshift));
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return readl(priv->membase + (reg << OMAP_UART_REGSHIFT));
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}
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static void uart_write(struct omap8250_priv *priv, u32 reg, u32 val)
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{
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writel(val, priv->membase + (reg << OMAP_UART_REGSHIFT));
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}
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/*
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@ -548,7 +555,7 @@ static void omap_serial_fill_features_erratas(struct uart_8250_port *up,
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u32 mvr, scheme;
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u16 revision, major, minor;
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mvr = uart_read(up, UART_OMAP_MVER);
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mvr = uart_read(priv, UART_OMAP_MVER);
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/* Check revision register scheme */
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scheme = mvr >> OMAP_UART_MVR_SCHEME_SHIFT;
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@ -1394,7 +1401,7 @@ static int omap8250_probe(struct platform_device *pdev)
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UPF_HARD_FLOW;
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up.port.private_data = priv;
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up.port.regshift = 2;
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up.port.regshift = OMAP_UART_REGSHIFT;
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up.port.fifosize = 64;
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up.tx_loadsz = 64;
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up.capabilities = UART_CAP_FIFO;
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@ -1457,6 +1464,8 @@ static int omap8250_probe(struct platform_device *pdev)
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DEFAULT_CLK_SPEED);
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}
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priv->membase = membase;
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priv->line = -ENODEV;
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priv->latency = PM_QOS_CPU_LATENCY_DEFAULT_VALUE;
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priv->calc_latency = PM_QOS_CPU_LATENCY_DEFAULT_VALUE;
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cpu_latency_qos_add_request(&priv->pm_qos_request, priv->latency);
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@ -1464,6 +1473,8 @@ static int omap8250_probe(struct platform_device *pdev)
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spin_lock_init(&priv->rx_dma_lock);
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platform_set_drvdata(pdev, priv);
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device_init_wakeup(&pdev->dev, true);
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pm_runtime_enable(&pdev->dev);
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pm_runtime_use_autosuspend(&pdev->dev);
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@ -1525,7 +1536,6 @@ static int omap8250_probe(struct platform_device *pdev)
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goto err;
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}
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priv->line = ret;
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platform_set_drvdata(pdev, priv);
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pm_runtime_mark_last_busy(&pdev->dev);
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pm_runtime_put_autosuspend(&pdev->dev);
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return 0;
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@ -1547,11 +1557,12 @@ static int omap8250_remove(struct platform_device *pdev)
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if (err)
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return err;
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serial8250_unregister_port(priv->line);
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priv->line = -ENODEV;
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pm_runtime_dont_use_autosuspend(&pdev->dev);
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pm_runtime_put_sync(&pdev->dev);
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flush_work(&priv->qos_work);
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pm_runtime_disable(&pdev->dev);
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serial8250_unregister_port(priv->line);
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cpu_latency_qos_remove_request(&priv->pm_qos_request);
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device_init_wakeup(&pdev->dev, false);
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return 0;
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@ -1627,7 +1638,6 @@ static int omap8250_lost_context(struct uart_8250_port *up)
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static int omap8250_soft_reset(struct device *dev)
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{
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struct omap8250_priv *priv = dev_get_drvdata(dev);
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struct uart_8250_port *up = serial8250_get_port(priv->line);
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int timeout = 100;
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int sysc;
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int syss;
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@ -1641,20 +1651,20 @@ static int omap8250_soft_reset(struct device *dev)
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* needing omap8250_soft_reset() quirk. Do it in two writes as
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* recommended in the comment for omap8250_update_scr().
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*/
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serial_out(up, UART_OMAP_SCR, OMAP_UART_SCR_DMAMODE_1);
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serial_out(up, UART_OMAP_SCR,
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uart_write(priv, UART_OMAP_SCR, OMAP_UART_SCR_DMAMODE_1);
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uart_write(priv, UART_OMAP_SCR,
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OMAP_UART_SCR_DMAMODE_1 | OMAP_UART_SCR_DMAMODE_CTL);
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sysc = serial_in(up, UART_OMAP_SYSC);
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sysc = uart_read(priv, UART_OMAP_SYSC);
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/* softreset the UART */
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sysc |= OMAP_UART_SYSC_SOFTRESET;
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serial_out(up, UART_OMAP_SYSC, sysc);
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uart_write(priv, UART_OMAP_SYSC, sysc);
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/* By experiments, 1us enough for reset complete on AM335x */
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do {
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udelay(1);
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syss = serial_in(up, UART_OMAP_SYSS);
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syss = uart_read(priv, UART_OMAP_SYSS);
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} while (--timeout && !(syss & OMAP_UART_SYSS_RESETDONE));
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if (!timeout) {
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@ -1668,13 +1678,10 @@ static int omap8250_soft_reset(struct device *dev)
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static int omap8250_runtime_suspend(struct device *dev)
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{
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struct omap8250_priv *priv = dev_get_drvdata(dev);
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struct uart_8250_port *up;
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struct uart_8250_port *up = NULL;
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/* In case runtime-pm tries this before we are setup */
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if (!priv)
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return 0;
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up = serial8250_get_port(priv->line);
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if (priv->line >= 0)
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up = serial8250_get_port(priv->line);
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/*
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* When using 'no_console_suspend', the console UART must not be
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* suspended. Since driver suspend is managed by runtime suspend,
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@ -1682,7 +1689,7 @@ static int omap8250_runtime_suspend(struct device *dev)
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* active during suspend.
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*/
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if (priv->is_suspending && !console_suspend_enabled) {
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if (uart_console(&up->port))
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if (up && uart_console(&up->port))
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return -EBUSY;
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}
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@ -1693,13 +1700,15 @@ static int omap8250_runtime_suspend(struct device *dev)
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if (ret)
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return ret;
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/* Restore to UART mode after reset (for wakeup) */
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omap8250_update_mdr1(up, priv);
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/* Restore wakeup enable register */
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serial_out(up, UART_OMAP_WER, priv->wer);
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if (up) {
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/* Restore to UART mode after reset (for wakeup) */
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omap8250_update_mdr1(up, priv);
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/* Restore wakeup enable register */
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serial_out(up, UART_OMAP_WER, priv->wer);
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}
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}
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if (up->dma && up->dma->rxchan)
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if (up && up->dma && up->dma->rxchan)
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omap_8250_rx_dma_flush(up);
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priv->latency = PM_QOS_CPU_LATENCY_DEFAULT_VALUE;
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@ -1711,18 +1720,15 @@ static int omap8250_runtime_suspend(struct device *dev)
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static int omap8250_runtime_resume(struct device *dev)
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{
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struct omap8250_priv *priv = dev_get_drvdata(dev);
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struct uart_8250_port *up;
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struct uart_8250_port *up = NULL;
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/* In case runtime-pm tries this before we are setup */
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if (!priv)
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return 0;
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if (priv->line >= 0)
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up = serial8250_get_port(priv->line);
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up = serial8250_get_port(priv->line);
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if (omap8250_lost_context(up))
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if (up && omap8250_lost_context(up))
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omap8250_restore_regs(up);
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if (up->dma && up->dma->rxchan && !(priv->habit & UART_HAS_EFR2))
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if (up && up->dma && up->dma->rxchan && !(priv->habit & UART_HAS_EFR2))
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omap_8250_rx_dma(up);
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priv->latency = priv->calc_latency;
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