| Message ID | 20120821130134.GH10347@arwen.pp.htv.fi (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Hi, On Tue, Aug 21, 2012 at 04:01:36PM +0300, Felipe Balbi wrote: > Hi, > > On Tue, Aug 21, 2012 at 03:15:58PM +0300, Felipe Balbi wrote: > > Hi guys, > > > > here's a series of cleanup patches to the OMAP serial > > driver. A later series could be made re-implementing > > DMA using the DMA Engine API. Note that for RX DMA > > we could be using RX Timeout IRQ as a hint that we better > > use PIO instead ;-) > > > > All patches were tested on my pandaboard, but I'd really > > like to receive Tested-by on other platforms. > > > > After this goes in, I'll probably try to get UART wakeup > > working again and only after that look at DMA. > > > > Changes since v1: > > > > . improved commit log on patch 9/13 (formerly 10/13) > > . removed patch 2/13 > > . added a new patch switching from spin_lock_irqsave() to spin_lock and > > spin_unlock_irqrestore to spin_unlock > > > > Retested with my pandaboard, UART continues to work: > > > > # grep -i uart /proc/interrupts > > 106: 124 0 GIC OMAP UART2 > > # grep -i uart /proc/interrupts > > 106: 189 0 GIC OMAP UART2 > > # grep -i uart /proc/interrupts > > 106: 255 0 GIC OMAP UART2 > > # grep -i uart /proc/interrupts > > 106: 321 0 GIC OMAP UART2 > > # grep -i uart /proc/interrupts > > 106: 387 0 GIC OMAP UART2 > > # grep -i uart /proc/interrupts > > 106: 453 0 GIC OMAP UART2 > > # grep -i uart /proc/interrupts > > 106: 519 0 GIC OMAP UART2 > > > > cheers > > > > ps: if anyone knows a better test for UART, let me know. > > > > for convenience of anyone testing, patches are available on my git tree [1] on > > branch uart > > > > [1] git://git.kernel.org/pub/scm/linux/kernel/git/balbi/usb.git uart > > I have added one extra patch to this series: > > From 6921efdb13dda7af216b331bb35535d4b53f004a Mon Sep 17 00:00:00 2001 > From: Felipe Balbi <balbi@ti.com> > Date: Tue, 21 Aug 2012 15:48:35 +0300 > Subject: [PATCH] serial: omap: drop pm_runtime_irq_safe() usage > > pm_runtime_irq_safe() will essentially do an > unbalanced pm_runtime_get_sync() on our parent > device, which might cause problems when trying > to suspend. > > In order to prevent that we drop pm_runtime_irq_safe > usage in exchange for a little performance hit > when we enter our IRQ handler while still suspended. > > If that happens, what we will do is set the irq_pending > flag, do an asynchronous pm_runtime_get() call and > return IRQ_HANDLED. When our runtime_resume() callback > is executed, we check for that flag, and run our > IRQ handler so that we receive/transmit the pending > characters. > > Signed-off-by: Felipe Balbi <balbi@ti.com> > --- > > One extra patch to OMAP UART driver. This seems to be working > pretty well even after echo mem > /sys/power/state. I can > see that I can even wake my pandaboard up by sending a character > through serial: > > # echo mem > /sys/power/state > [ 1335.679260] PM: Syncing filesystems ... done. > [ 1335.684387] Freezing user space processes ... (elapsed 0.00 seconds) done. > [ 1335.691741] Freezing remaining freezable tasks ... (elapsed 0.02 seconds) done. > [ 1335.720886] Suspending console(s) (use no_console_suspend to debug) > > [ 1335.734405] PM: suspend of devices complete after 5.492 msecs > [ 1335.735534] PM: late suspend of devices complete after 1.128 msecs > [ 1335.737518] PM: noirq suspend of devices complete after 1.952 msecs > [ 1335.737518] Disabling non-boot CPUs ... > [ 1335.738525] CPU1: shutdown > [ 1338.543762] Successfully put all powerdomains to target state > [ 1338.543853] Enabling non-boot CPUs ... > [ 1338.545654] CPU1: Booted secondary processor > [ 1338.546020] CPU1 is up > [ 1338.547027] PM: noirq resume of devices complete after 0.976 msecs > [ 1338.548400] PM: early resume of devices complete after 0.762 msecs > [ 1339.827087] PM: resume of devices complete after 1278.686 msecs > [ 1339.890960] Restarting tasks ... done. > # # grep -i uart /proc/interrupts > 106: 3385 0 GIC OMAP UART2 > # echo mem > /sys/power/state > [ 1358.015624] PM: Syncing filesystems ... done. > [ 1358.020812] Freezing user space processes ... (elapsed 0.00 seconds) done. > [ 1358.028167] Freezing remaining freezable tasks ... (elapsed 0.01 seconds) done. > [ 1358.055084] Suspending console(s) (use no_console_suspend to debug) > > [ 1358.068847] PM: suspend of devices complete after 5.633 msecs > [ 1358.070007] PM: late suspend of devices complete after 1.126 msecs > [ 1358.072051] PM: noirq suspend of devices complete after 2.040 msecs > [ 1358.072051] Disabling non-boot CPUs ... > [ 1358.073211] CPU1: shutdown > [ 1359.104156] Successfully put all powerdomains to target state > [ 1359.104278] Enabling non-boot CPUs ... > [ 1359.106079] CPU1: Booted secondary processor > [ 1359.106475] CPU1 is up > [ 1359.107482] PM: noirq resume of devices complete after 1.004 msecs > [ 1359.108886] PM: early resume of devices complete after 0.761 msecs > [ 1360.414794] PM: resume of devices complete after 1305.836 msecs > [ 1360.478668] Restarting tasks ... done. > # # grep -i uart /proc/interrupts > 106: 3511 0 GIC OMAP UART2 > > arch/arm/plat-omap/include/plat/omap-serial.h | 1 + > drivers/tty/serial/omap-serial.c | 16 +++++++++++++--- > 2 files changed, 14 insertions(+), 3 deletions(-) > > diff --git a/arch/arm/plat-omap/include/plat/omap-serial.h b/arch/arm/plat-omap/include/plat/omap-serial.h > index 743ac80..52328ca 100644 > --- a/arch/arm/plat-omap/include/plat/omap-serial.h > +++ b/arch/arm/plat-omap/include/plat/omap-serial.h > @@ -130,6 +130,7 @@ struct uart_omap_port { > u32 context_loss_cnt; > u32 errata; > u8 wakeups_enabled; > + unsigned int irq_pending:1; > > struct pm_qos_request pm_qos_request; > u32 latency; > diff --git a/drivers/tty/serial/omap-serial.c b/drivers/tty/serial/omap-serial.c > index a79658d..7e237f3 100644 > --- a/drivers/tty/serial/omap-serial.c > +++ b/drivers/tty/serial/omap-serial.c > @@ -353,9 +353,13 @@ static inline irqreturn_t serial_omap_irq(int irq, void *dev_id) > irqreturn_t ret = IRQ_HANDLED; > int max_count = 256; > > - spin_lock(&up->port.lock); > - pm_runtime_get_sync(up->dev); > + if (pm_runtime_suspended(up->dev)) { > + up->irq_pending = true; > + pm_runtime_get(up->dev); > + return IRQ_HANDLED; > + } > > + spin_lock(&up->port.lock); > do { > iir = serial_in(up, UART_IIR); > if (iir & UART_IIR_NO_INT) { > @@ -400,6 +404,7 @@ static inline irqreturn_t serial_omap_irq(int irq, void *dev_id) > pm_runtime_mark_last_busy(up->dev); > pm_runtime_put_autosuspend(up->dev); > up->port_activity = jiffies; > + up->irq_pending = false; > > return ret; > } > @@ -1305,7 +1310,6 @@ static int serial_omap_probe(struct platform_device *pdev) > pm_runtime_set_autosuspend_delay(&pdev->dev, > omap_up_info->autosuspend_timeout); > > - pm_runtime_irq_safe(&pdev->dev); > pm_runtime_enable(&pdev->dev); > pm_runtime_get_sync(&pdev->dev); > > @@ -1416,6 +1420,9 @@ static int serial_omap_runtime_suspend(struct device *dev) > if (!up) > return -EINVAL; > > + if (up->irq_pending) > + return -EBUSY; > + > if (!pdata) > return 0; > > @@ -1452,6 +1459,9 @@ static int serial_omap_runtime_resume(struct device *dev) > > up->latency = up->calc_latency; > schedule_work(&up->qos_work); > + > + if (up->irq_pending) > + serial_omap_irq(up->port.irq, up); > } > > return 0; let's not apply this extra patch. It actually caused a regression which was pretty difficult to trigger. I have now dropped it from my series. Sorry for the noise.
diff --git a/arch/arm/plat-omap/include/plat/omap-serial.h b/arch/arm/plat-omap/include/plat/omap-serial.h index 743ac80..52328ca 100644 --- a/arch/arm/plat-omap/include/plat/omap-serial.h +++ b/arch/arm/plat-omap/include/plat/omap-serial.h @@ -130,6 +130,7 @@ struct uart_omap_port { u32 context_loss_cnt; u32 errata; u8 wakeups_enabled; + unsigned int irq_pending:1; struct pm_qos_request pm_qos_request; u32 latency; diff --git a/drivers/tty/serial/omap-serial.c b/drivers/tty/serial/omap-serial.c index a79658d..7e237f3 100644 --- a/drivers/tty/serial/omap-serial.c +++ b/drivers/tty/serial/omap-serial.c @@ -353,9 +353,13 @@ static inline irqreturn_t serial_omap_irq(int irq, void *dev_id) irqreturn_t ret = IRQ_HANDLED; int max_count = 256; - spin_lock(&up->port.lock); - pm_runtime_get_sync(up->dev); + if (pm_runtime_suspended(up->dev)) { + up->irq_pending = true; + pm_runtime_get(up->dev); + return IRQ_HANDLED; + } + spin_lock(&up->port.lock); do { iir = serial_in(up, UART_IIR); if (iir & UART_IIR_NO_INT) { @@ -400,6 +404,7 @@ static inline irqreturn_t serial_omap_irq(int irq, void *dev_id) pm_runtime_mark_last_busy(up->dev); pm_runtime_put_autosuspend(up->dev); up->port_activity = jiffies; + up->irq_pending = false; return ret; } @@ -1305,7 +1310,6 @@ static int serial_omap_probe(struct platform_device *pdev) pm_runtime_set_autosuspend_delay(&pdev->dev, omap_up_info->autosuspend_timeout); - pm_runtime_irq_safe(&pdev->dev); pm_runtime_enable(&pdev->dev); pm_runtime_get_sync(&pdev->dev); @@ -1416,6 +1420,9 @@ static int serial_omap_runtime_suspend(struct device *dev) if (!up) return -EINVAL; + if (up->irq_pending) + return -EBUSY; + if (!pdata) return 0; @@ -1452,6 +1459,9 @@ static int serial_omap_runtime_resume(struct device *dev) up->latency = up->calc_latency; schedule_work(&up->qos_work); + + if (up->irq_pending) + serial_omap_irq(up->port.irq, up); } return 0;