Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753683AbdCOLTF (ORCPT ); Wed, 15 Mar 2017 07:19:05 -0400 Received: from mail-wm0-f47.google.com ([74.125.82.47]:38082 "EHLO mail-wm0-f47.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751920AbdCOLRt (ORCPT ); Wed, 15 Mar 2017 07:17:49 -0400 Date: Wed, 15 Mar 2017 11:17:44 +0000 From: Lee Jones To: Julia Cartwright Cc: linux-kernel@vger.kernel.org, Thomas Gleixner Subject: Re: [PATCH 14/19] mfd: t7l66xb: make use of raw_spinlock variants Message-ID: <20170315111744.nb67cjfkjwtrjvcf@dell> References: <72bbb1d0c4a9ae4c4f6d9dfadfdf870a03c522e0.1489015238.git.julia@ni.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <72bbb1d0c4a9ae4c4f6d9dfadfdf870a03c522e0.1489015238.git.julia@ni.com> User-Agent: Mutt/1.6.2-neo (2016-08-21) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3953 Lines: 110 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 > --- > 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