6.1-stable review patch. If anyone has any objections, please let me know.
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From: Tony Lindgren tony@atomide.com
[ Upstream commit 398cecc24846e867b9f90a0bd22730e3df6b05be ]
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 Stable-dep-of: 560706eff7c8 ("serial: 8250_omap: Fix errors with no_console_suspend") Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/tty/serial/8250/8250_omap.c | 70 ++++++++++++++++------------- 1 file changed, 38 insertions(+), 32 deletions(-)
diff --git a/drivers/tty/serial/8250/8250_omap.c b/drivers/tty/serial/8250/8250_omap.c index adc85e250822c..0aed614110090 100644 --- a/drivers/tty/serial/8250/8250_omap.c +++ b/drivers/tty/serial/8250/8250_omap.c @@ -32,6 +32,7 @@ #include "8250.h"
#define DEFAULT_CLK_SPEED 48000000 +#define OMAP_UART_REGSHIFT 2
#define UART_ERRATA_i202_MDR1_ACCESS (1 << 0) #define OMAP_UART_WER_HAS_TX_WAKEUP (1 << 1) @@ -109,6 +110,7 @@ #define UART_OMAP_RX_LVL 0x19
struct omap8250_priv { + void __iomem *membase; int line; u8 habit; u8 mdr1; @@ -152,9 +154,14 @@ static void omap_8250_rx_dma_flush(struct uart_8250_port *p); static inline void omap_8250_rx_dma_flush(struct uart_8250_port *p) { } #endif
-static u32 uart_read(struct uart_8250_port *up, u32 reg) +static u32 uart_read(struct omap8250_priv *priv, u32 reg) { - return readl(up->port.membase + (reg << up->port.regshift)); + return readl(priv->membase + (reg << OMAP_UART_REGSHIFT)); +} + +static void uart_write(struct omap8250_priv *priv, u32 reg, u32 val) +{ + writel(val, priv->membase + (reg << OMAP_UART_REGSHIFT)); }
/* @@ -538,7 +545,7 @@ static void omap_serial_fill_features_erratas(struct uart_8250_port *up, u32 mvr, scheme; u16 revision, major, minor;
- mvr = uart_read(up, UART_OMAP_MVER); + mvr = uart_read(priv, UART_OMAP_MVER);
/* Check revision register scheme */ scheme = mvr >> OMAP_UART_MVR_SCHEME_SHIFT; @@ -1319,7 +1326,7 @@ static int omap8250_probe(struct platform_device *pdev) UPF_HARD_FLOW; up.port.private_data = priv;
- up.port.regshift = 2; + up.port.regshift = OMAP_UART_REGSHIFT; up.port.fifosize = 64; up.tx_loadsz = 64; up.capabilities = UART_CAP_FIFO; @@ -1381,6 +1388,8 @@ static int omap8250_probe(struct platform_device *pdev) DEFAULT_CLK_SPEED); }
+ priv->membase = membase; + priv->line = -ENODEV; priv->latency = PM_QOS_CPU_LATENCY_DEFAULT_VALUE; priv->calc_latency = PM_QOS_CPU_LATENCY_DEFAULT_VALUE; cpu_latency_qos_add_request(&priv->pm_qos_request, priv->latency); @@ -1388,6 +1397,8 @@ static int omap8250_probe(struct platform_device *pdev)
spin_lock_init(&priv->rx_dma_lock);
+ platform_set_drvdata(pdev, priv); + device_init_wakeup(&pdev->dev, true); pm_runtime_enable(&pdev->dev); pm_runtime_use_autosuspend(&pdev->dev); @@ -1449,7 +1460,6 @@ static int omap8250_probe(struct platform_device *pdev) goto err; } priv->line = ret; - platform_set_drvdata(pdev, priv); pm_runtime_mark_last_busy(&pdev->dev); pm_runtime_put_autosuspend(&pdev->dev); return 0; @@ -1471,11 +1481,12 @@ static int omap8250_remove(struct platform_device *pdev) if (err) return err;
+ serial8250_unregister_port(priv->line); + priv->line = -ENODEV; pm_runtime_dont_use_autosuspend(&pdev->dev); pm_runtime_put_sync(&pdev->dev); flush_work(&priv->qos_work); pm_runtime_disable(&pdev->dev); - serial8250_unregister_port(priv->line); cpu_latency_qos_remove_request(&priv->pm_qos_request); device_init_wakeup(&pdev->dev, false); return 0; @@ -1561,7 +1572,6 @@ static int omap8250_lost_context(struct uart_8250_port *up) static int omap8250_soft_reset(struct device *dev) { struct omap8250_priv *priv = dev_get_drvdata(dev); - struct uart_8250_port *up = serial8250_get_port(priv->line); int timeout = 100; int sysc; int syss; @@ -1575,20 +1585,20 @@ static int omap8250_soft_reset(struct device *dev) * needing omap8250_soft_reset() quirk. Do it in two writes as * recommended in the comment for omap8250_update_scr(). */ - serial_out(up, UART_OMAP_SCR, OMAP_UART_SCR_DMAMODE_1); - serial_out(up, UART_OMAP_SCR, + uart_write(priv, UART_OMAP_SCR, OMAP_UART_SCR_DMAMODE_1); + uart_write(priv, UART_OMAP_SCR, OMAP_UART_SCR_DMAMODE_1 | OMAP_UART_SCR_DMAMODE_CTL);
- sysc = serial_in(up, UART_OMAP_SYSC); + sysc = uart_read(priv, UART_OMAP_SYSC);
/* softreset the UART */ sysc |= OMAP_UART_SYSC_SOFTRESET; - serial_out(up, UART_OMAP_SYSC, sysc); + uart_write(priv, UART_OMAP_SYSC, sysc);
/* By experiments, 1us enough for reset complete on AM335x */ do { udelay(1); - syss = serial_in(up, UART_OMAP_SYSS); + syss = uart_read(priv, UART_OMAP_SYSS); } while (--timeout && !(syss & OMAP_UART_SYSS_RESETDONE));
if (!timeout) { @@ -1602,13 +1612,10 @@ static int omap8250_soft_reset(struct device *dev) static int omap8250_runtime_suspend(struct device *dev) { struct omap8250_priv *priv = dev_get_drvdata(dev); - struct uart_8250_port *up; - - /* In case runtime-pm tries this before we are setup */ - if (!priv) - return 0; + struct uart_8250_port *up = NULL;
- up = serial8250_get_port(priv->line); + if (priv->line >= 0) + up = serial8250_get_port(priv->line); /* * When using 'no_console_suspend', the console UART must not be * suspended. Since driver suspend is managed by runtime suspend, @@ -1616,7 +1623,7 @@ static int omap8250_runtime_suspend(struct device *dev) * active during suspend. */ if (priv->is_suspending && !console_suspend_enabled) { - if (uart_console(&up->port)) + if (up && uart_console(&up->port)) return -EBUSY; }
@@ -1627,13 +1634,15 @@ static int omap8250_runtime_suspend(struct device *dev) if (ret) return ret;
- /* Restore to UART mode after reset (for wakeup) */ - omap8250_update_mdr1(up, priv); - /* Restore wakeup enable register */ - serial_out(up, UART_OMAP_WER, priv->wer); + if (up) { + /* Restore to UART mode after reset (for wakeup) */ + omap8250_update_mdr1(up, priv); + /* Restore wakeup enable register */ + serial_out(up, UART_OMAP_WER, priv->wer); + } }
- if (up->dma && up->dma->rxchan) + if (up && up->dma && up->dma->rxchan) omap_8250_rx_dma_flush(up);
priv->latency = PM_QOS_CPU_LATENCY_DEFAULT_VALUE; @@ -1645,18 +1654,15 @@ static int omap8250_runtime_suspend(struct device *dev) static int omap8250_runtime_resume(struct device *dev) { struct omap8250_priv *priv = dev_get_drvdata(dev); - struct uart_8250_port *up; - - /* In case runtime-pm tries this before we are setup */ - if (!priv) - return 0; + struct uart_8250_port *up = NULL;
- up = serial8250_get_port(priv->line); + if (priv->line >= 0) + up = serial8250_get_port(priv->line);
- if (omap8250_lost_context(up)) + if (up && omap8250_lost_context(up)) omap8250_restore_regs(up);
- if (up->dma && up->dma->rxchan && !(priv->habit & UART_HAS_EFR2)) + if (up && up->dma && up->dma->rxchan && !(priv->habit & UART_HAS_EFR2)) omap_8250_rx_dma(up);
priv->latency = priv->calc_latency;