lkml.org 
[lkml]   [2017]   [Mar]   [15]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [PATCH 14/19] mfd: t7l66xb: make use of raw_spinlock variants
    On Thu, 09 Mar 2017, Julia Cartwright wrote:

    > The t7l66xb mfd driver currently implements an irq_chip for handling
    > interrupts; due to how irq_chip handling is done, it's necessary for the
    > irq_chip methods to be invoked from hardirq context, even on a a
    > real-time kernel. Because the spinlock_t type becomes a "sleeping"
    > spinlock w/ RT kernels, it is not suitable to be used with irq_chips.
    >
    > A quick audit of the operations under the lock reveal that they do only
    > minimal, bounded work, and are therefore safe to do under a raw spinlock.
    >
    > Signed-off-by: Julia Cartwright <julia@ni.com>
    > ---
    > drivers/mfd/t7l66xb.c | 20 ++++++++++----------
    > 1 file changed, 10 insertions(+), 10 deletions(-)

    Can the 3 MFD patches in this set be applied on their own, or is there
    a dependency somewhere else in the set?

    NB: It's normally a good idea to send the set to everyone, or at the
    very least, the 00/00th patch.

    > diff --git a/drivers/mfd/t7l66xb.c b/drivers/mfd/t7l66xb.c
    > index 94bd89cb1f06..22c811396edc 100644
    > --- a/drivers/mfd/t7l66xb.c
    > +++ b/drivers/mfd/t7l66xb.c
    > @@ -69,7 +69,7 @@ static const struct resource t7l66xb_mmc_resources[] = {
    > struct t7l66xb {
    > void __iomem *scr;
    > /* Lock to protect registers requiring read/modify/write ops. */
    > - spinlock_t lock;
    > + raw_spinlock_t lock;
    >
    > struct resource rscr;
    > struct clk *clk48m;
    > @@ -89,13 +89,13 @@ static int t7l66xb_mmc_enable(struct platform_device *mmc)
    >
    > clk_prepare_enable(t7l66xb->clk32k);
    >
    > - spin_lock_irqsave(&t7l66xb->lock, flags);
    > + raw_spin_lock_irqsave(&t7l66xb->lock, flags);
    >
    > dev_ctl = tmio_ioread8(t7l66xb->scr + SCR_DEV_CTL);
    > dev_ctl |= SCR_DEV_CTL_MMC;
    > tmio_iowrite8(dev_ctl, t7l66xb->scr + SCR_DEV_CTL);
    >
    > - spin_unlock_irqrestore(&t7l66xb->lock, flags);
    > + raw_spin_unlock_irqrestore(&t7l66xb->lock, flags);
    >
    > tmio_core_mmc_enable(t7l66xb->scr + 0x200, 0,
    > t7l66xb_mmc_resources[0].start & 0xfffe);
    > @@ -110,13 +110,13 @@ static int t7l66xb_mmc_disable(struct platform_device *mmc)
    > unsigned long flags;
    > u8 dev_ctl;
    >
    > - spin_lock_irqsave(&t7l66xb->lock, flags);
    > + raw_spin_lock_irqsave(&t7l66xb->lock, flags);
    >
    > dev_ctl = tmio_ioread8(t7l66xb->scr + SCR_DEV_CTL);
    > dev_ctl &= ~SCR_DEV_CTL_MMC;
    > tmio_iowrite8(dev_ctl, t7l66xb->scr + SCR_DEV_CTL);
    >
    > - spin_unlock_irqrestore(&t7l66xb->lock, flags);
    > + raw_spin_unlock_irqrestore(&t7l66xb->lock, flags);
    >
    > clk_disable_unprepare(t7l66xb->clk32k);
    >
    > @@ -206,11 +206,11 @@ static void t7l66xb_irq_mask(struct irq_data *data)
    > unsigned long flags;
    > u8 imr;
    >
    > - spin_lock_irqsave(&t7l66xb->lock, flags);
    > + raw_spin_lock_irqsave(&t7l66xb->lock, flags);
    > imr = tmio_ioread8(t7l66xb->scr + SCR_IMR);
    > imr |= 1 << (data->irq - t7l66xb->irq_base);
    > tmio_iowrite8(imr, t7l66xb->scr + SCR_IMR);
    > - spin_unlock_irqrestore(&t7l66xb->lock, flags);
    > + raw_spin_unlock_irqrestore(&t7l66xb->lock, flags);
    > }
    >
    > static void t7l66xb_irq_unmask(struct irq_data *data)
    > @@ -219,11 +219,11 @@ static void t7l66xb_irq_unmask(struct irq_data *data)
    > unsigned long flags;
    > u8 imr;
    >
    > - spin_lock_irqsave(&t7l66xb->lock, flags);
    > + raw_spin_lock_irqsave(&t7l66xb->lock, flags);
    > imr = tmio_ioread8(t7l66xb->scr + SCR_IMR);
    > imr &= ~(1 << (data->irq - t7l66xb->irq_base));
    > tmio_iowrite8(imr, t7l66xb->scr + SCR_IMR);
    > - spin_unlock_irqrestore(&t7l66xb->lock, flags);
    > + raw_spin_unlock_irqrestore(&t7l66xb->lock, flags);
    > }
    >
    > static struct irq_chip t7l66xb_chip = {
    > @@ -321,7 +321,7 @@ static int t7l66xb_probe(struct platform_device *dev)
    > if (!t7l66xb)
    > return -ENOMEM;
    >
    > - spin_lock_init(&t7l66xb->lock);
    > + raw_spin_lock_init(&t7l66xb->lock);
    >
    > platform_set_drvdata(dev, t7l66xb);
    >

    --
    Lee Jones
    Linaro STMicroelectronics Landing Team Lead
    Linaro.org │ Open source software for ARM SoCs
    Follow Linaro: Facebook | Twitter | Blog

    \
     
     \ /
      Last update: 2017-03-15 12:22    [W:3.199 / U:0.408 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site