Messages in this thread | | | Subject | Re: [PATCH V2 09/15] coresight: tmc: adding mode of operation for link/sinks | From | Suzuki K Poulose <> | Date | Tue, 19 Apr 2016 14:19:49 +0100 |
| |
On 12/04/16 18:54, Mathieu Poirier wrote: > Moving tmc_drvdata::enable to a local_t mode. That way the > sink interface is aware of it's orgin and the foundation for > mutual exclusion between the sysFS and Perf interface can be > laid out. > > Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org> > --- > drivers/hwtracing/coresight/coresight-tmc-etf.c | 28 ++++++++++++++++++------- > drivers/hwtracing/coresight/coresight-tmc-etr.c | 24 ++++++++++++++++----- > drivers/hwtracing/coresight/coresight-tmc.h | 4 ++-- > 3 files changed, 42 insertions(+), 14 deletions(-) > > diff --git a/drivers/hwtracing/coresight/coresight-tmc-etf.c b/drivers/hwtracing/coresight/coresight-tmc-etf.c > index 7cb287ef7b9e..5908000e1ae0 100644 > --- a/drivers/hwtracing/coresight/coresight-tmc-etf.c > +++ b/drivers/hwtracing/coresight/coresight-tmc-etf.c > @@ -110,6 +110,7 @@ static int tmc_enable_etf_sink(struct coresight_device *csdev, u32 mode) > { > bool allocated = false; > char *buf = NULL; > + u32 val; > unsigned long flags; > struct tmc_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent); > > @@ -146,6 +147,15 @@ fast_path: > return -EBUSY; > } > > + val = local_xchg(&drvdata->mode, mode); > + /* > + * In sysFS mode we can have multiple writers per sink. Since this > + * sink is already enabled no memory is needed and the HW need not be > + * touched. > + */ > + if (val == CS_MODE_SYSFS) > + goto out; > +
We are not dropping the spinlock in this case. Are we ?
> /* > * If drvdata::buf isn't NULL, memory was allocated for a previous > * trace run but wasn't read. If so simply zero-out the memory. > @@ -163,9 +173,9 @@ fast_path: > } > > tmc_etb_enable_hw(drvdata); > - drvdata->enable = true; > spin_unlock_irqrestore(&drvdata->spinlock, flags); > > +out: > /* Free memory outside the spinlock if need be */ > if (!allocated && buf) > kfree(buf);
> diff --git a/drivers/hwtracing/coresight/coresight-tmc-etr.c b/drivers/hwtracing/coresight/coresight-tmc-etr.c > index 6022ff26deba..8e6fe267195a 100644 > --- a/drivers/hwtracing/coresight/coresight-tmc-etr.c > +++ b/drivers/hwtracing/coresight/coresight-tmc-etr.c > @@ -85,6 +85,7 @@ static void tmc_etr_disable_hw(struct tmc_drvdata *drvdata) > static int tmc_enable_etr_sink(struct coresight_device *csdev, u32 mode) > { > bool allocated = false; > + u32 val; > unsigned long flags; > void __iomem *vaddr = NULL; > dma_addr_t paddr; > @@ -125,6 +126,15 @@ fast_path: > return -EBUSY; > } > > + val = local_xchg(&drvdata->mode, mode); > + /* > + * In sysFS mode we can have multiple writers per sink. Since this > + * sink is already enabled no memory is needed and the HW need not be > + * touched. > + */ > + if (val == CS_MODE_SYSFS) > + goto out; > +
Same as above, we should drop the locks in this case.
> @@ -140,9 +150,9 @@ fast_path: > memset(drvdata->vaddr, 0, drvdata->size); > > tmc_etr_enable_hw(drvdata); > - drvdata->enable = true; > spin_unlock_irqrestore(&drvdata->spinlock, flags); > > +out: > /* Free memory outside the spinlock if need be */ > if (!allocated && vaddr) > dma_free_coherent(drvdata->dev, drvdata->size, vaddr, paddr); > @@ -153,6 +163,7 @@ fast_path:
> diff --git a/drivers/hwtracing/coresight/coresight-tmc.h b/drivers/hwtracing/coresight/coresight-tmc.h > index 80096fa75326..821bdf150ac9 100644 > --- a/drivers/hwtracing/coresight/coresight-tmc.h > +++ b/drivers/hwtracing/coresight/coresight-tmc.h > @@ -100,7 +100,7 @@ enum tmc_mem_intf_width { > * @paddr: DMA start location in RAM. > * @vaddr: virtual representation of @paddr. > * @size: @buf size. > - * @enable: this TMC is being used. > + * @mode: how this TMC is being used. > * @config_type: TMC variant, must be of type @tmc_config_type. > * @trigger_cntr: amount of words to store after a trigger. > */ > @@ -116,7 +116,7 @@ struct tmc_drvdata { > dma_addr_t paddr; > void __iomem *vaddr; > u32 size; > - bool enable; > + local_t mode;
Since we always deal with the mode under the spinlock, do we really need this to be local_t ? Or do we plan to get rid of the lock ?
Suzuki
| |