| Message ID | 1460483692-25061-10-git-send-email-mathieu.poirier@linaro.org |
|---|---|
| State | New |
| Headers | show |
On 19 April 2016 at 07:19, Suzuki K Poulose <Suzuki.Poulose@arm.com> wrote: > 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 ? Definitely - thanks for pointing that out. > >> /* >> * 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 ? You are correct, using a local_t variable isn't strictly needed here. But: 1) It greatly simplifies the code. 2) I'm really hoping one day we can do without the spinlocks, though I don't know when that will happen. Get back to me if you're resolute on switching the local_t to a normal type. Mathieu > > Suzuki >
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; + /* * 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); @@ -176,6 +186,7 @@ fast_path: static void tmc_disable_etf_sink(struct coresight_device *csdev) { + u32 val; unsigned long flags; struct tmc_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent); @@ -185,8 +196,11 @@ static void tmc_disable_etf_sink(struct coresight_device *csdev) return; } - tmc_etb_disable_hw(drvdata); - drvdata->enable = false; + val = local_xchg(&drvdata->mode, CS_MODE_DISABLED); + /* Disable the TMC only if it needs to */ + if (val != CS_MODE_DISABLED) + tmc_etb_disable_hw(drvdata); + spin_unlock_irqrestore(&drvdata->spinlock, flags); dev_info(drvdata->dev, "TMC-ETB/ETF disabled\n"); @@ -205,7 +219,7 @@ static int tmc_enable_etf_link(struct coresight_device *csdev, } tmc_etf_enable_hw(drvdata); - drvdata->enable = true; + local_set(&drvdata->mode, CS_MODE_SYSFS); spin_unlock_irqrestore(&drvdata->spinlock, flags); dev_info(drvdata->dev, "TMC-ETF enabled\n"); @@ -225,7 +239,7 @@ static void tmc_disable_etf_link(struct coresight_device *csdev, } tmc_etf_disable_hw(drvdata); - drvdata->enable = false; + local_set(&drvdata->mode, CS_MODE_DISABLED); spin_unlock_irqrestore(&drvdata->spinlock, flags); dev_info(drvdata->dev, "TMC disabled\n"); @@ -277,7 +291,7 @@ int tmc_read_prepare_etb(struct tmc_drvdata *drvdata) } /* Disable the TMC if need be */ - if (drvdata->enable) + if (local_read(&drvdata->mode) == CS_MODE_SYSFS) tmc_etb_disable_hw(drvdata); drvdata->reading = true; @@ -308,7 +322,7 @@ int tmc_read_unprepare_etb(struct tmc_drvdata *drvdata) } /* Re-enable the TMC if need be */ - if (drvdata->enable) { + if (local_read(&drvdata->mode) == CS_MODE_SYSFS) { /* * The trace run will continue with the same allocated trace * buffer. As such zero-out the buffer so that we don't end 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; + /* * If drvdata::buf == NULL, use the memory allocated above. * Otherwise a buffer still exists from a previous session, so @@ -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: static void tmc_disable_etr_sink(struct coresight_device *csdev) { + u32 val; unsigned long flags; struct tmc_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent); @@ -162,8 +173,11 @@ static void tmc_disable_etr_sink(struct coresight_device *csdev) return; } - tmc_etr_disable_hw(drvdata); - drvdata->enable = false; + val = local_xchg(&drvdata->mode, CS_MODE_DISABLED); + /* Disable the TMC only if it needs to */ + if (val != CS_MODE_DISABLED) + tmc_etr_disable_hw(drvdata); + spin_unlock_irqrestore(&drvdata->spinlock, flags); dev_info(drvdata->dev, "TMC-ETR disabled\n"); @@ -195,7 +209,7 @@ int tmc_read_prepare_etr(struct tmc_drvdata *drvdata) } /* Disable the TMC if need be */ - if (drvdata->enable) + if (local_read(&drvdata->mode) == CS_MODE_SYSFS) tmc_etr_disable_hw(drvdata); drvdata->reading = true; @@ -217,7 +231,7 @@ int tmc_read_unprepare_etr(struct tmc_drvdata *drvdata) spin_lock_irqsave(&drvdata->spinlock, flags); /* RE-enable the TMC if need be */ - if (drvdata->enable) { + if (local_read(&drvdata->mode) == CS_MODE_SYSFS) { /* * The trace run will continue with the same allocated trace * buffer. As such zero-out the buffer so that we don't end 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; enum tmc_config_type config_type; u32 trigger_cntr; };
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(-) -- 2.5.0