From: Suzuki K Poulose <suzuki.poulose@arm.com> To: mathieu.poirier@linaro.org Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, mike.leach@linaro.org, coresight@lists.linaro.org Subject: Re: [RFC PATCH 03/14] coresight: tpiu: Use coresight device access abstraction Date: Fri, 31 Jul 2020 12:36:55 +0100 [thread overview] Message-ID: <02f28b5f-d3d6-755f-066d-88b90aa35eef@arm.com> (raw) In-Reply-To: <20200729210105.GC3073178@xps15> On 07/29/2020 10:01 PM, Mathieu Poirier wrote: > On Wed, Jul 22, 2020 at 06:20:29PM +0100, Suzuki K Poulose wrote: >> TPIU driver access the device before the coresight device >> is registered. In other words, before the drvdata->csdev >> is valid. Thus, we need to make sure that the csdev_access >> is valid for both the invocations. Switch to using the >> csdev_access directly instead of relying on availability >> of drvdata->csdev. > > I'm not sure all of the above is needed and based on the wording I could easily > see this patch being selected for stable backport, which would be a mistak. > > The gist of this patch is that we are moving to the access abstraction and the > changelog should reflect that. True, I will make it something like : "Prepare the TPIU driver to make use of the CoreSight device access abstraction layer. The driver touches the device even before the coresight device is registered. Thus we could be accessing the devices without a csdev. As we are about to use the abstraction layer for accessing the device, pass in the access directly to avoid having to deal with the un-initialised csdev. >> >> static int tpiu_disable(struct coresight_device *csdev) >> { >> - struct tpiu_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent); >> - >> if (atomic_dec_return(csdev->refcnt)) >> return -EBUSY; >> >> - tpiu_disable_hw(drvdata); >> + tpiu_disable_hw(&csdev->access); >> >> dev_dbg(&csdev->dev, "TPIU disabled\n"); >> return 0; >> @@ -152,7 +148,7 @@ static int tpiu_probe(struct amba_device *adev, const struct amba_id *id) >> desc.access.base = base; > > Any reason for introducing the above in patch 02? I would have done that as > part of this patch... Also part of this patch I would remove drvdata::base > since it is no longer needed. The patch 02 is not touching how the individual drivers access the device, yet. It only sets the way by introducing the layer. As per the proposed change, this is a preparation of the TPIU driver, so that we can convert the generic helper functions ( coresight_timeout()) more easily and keep the patch 05 easier for review (just like the Patch 4, which prepares the ETM driver). Cheers Suzuki > > I'm out of time for today - I will continue tomorrow. > > Regards, > Mathieu > >> >> /* Disable tpiu to support older devices */ >> - tpiu_disable_hw(drvdata); >> + tpiu_disable_hw(&desc.access); >> >> pdata = coresight_get_platform_data(dev); >> if (IS_ERR(pdata)) >> -- >> 2.24.1 >>
WARNING: multiple messages have this Message-ID (diff)
From: Suzuki K Poulose <suzuki.poulose@arm.com> To: mathieu.poirier@linaro.org Cc: coresight@lists.linaro.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, mike.leach@linaro.org Subject: Re: [RFC PATCH 03/14] coresight: tpiu: Use coresight device access abstraction Date: Fri, 31 Jul 2020 12:36:55 +0100 [thread overview] Message-ID: <02f28b5f-d3d6-755f-066d-88b90aa35eef@arm.com> (raw) In-Reply-To: <20200729210105.GC3073178@xps15> On 07/29/2020 10:01 PM, Mathieu Poirier wrote: > On Wed, Jul 22, 2020 at 06:20:29PM +0100, Suzuki K Poulose wrote: >> TPIU driver access the device before the coresight device >> is registered. In other words, before the drvdata->csdev >> is valid. Thus, we need to make sure that the csdev_access >> is valid for both the invocations. Switch to using the >> csdev_access directly instead of relying on availability >> of drvdata->csdev. > > I'm not sure all of the above is needed and based on the wording I could easily > see this patch being selected for stable backport, which would be a mistak. > > The gist of this patch is that we are moving to the access abstraction and the > changelog should reflect that. True, I will make it something like : "Prepare the TPIU driver to make use of the CoreSight device access abstraction layer. The driver touches the device even before the coresight device is registered. Thus we could be accessing the devices without a csdev. As we are about to use the abstraction layer for accessing the device, pass in the access directly to avoid having to deal with the un-initialised csdev. >> >> static int tpiu_disable(struct coresight_device *csdev) >> { >> - struct tpiu_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent); >> - >> if (atomic_dec_return(csdev->refcnt)) >> return -EBUSY; >> >> - tpiu_disable_hw(drvdata); >> + tpiu_disable_hw(&csdev->access); >> >> dev_dbg(&csdev->dev, "TPIU disabled\n"); >> return 0; >> @@ -152,7 +148,7 @@ static int tpiu_probe(struct amba_device *adev, const struct amba_id *id) >> desc.access.base = base; > > Any reason for introducing the above in patch 02? I would have done that as > part of this patch... Also part of this patch I would remove drvdata::base > since it is no longer needed. The patch 02 is not touching how the individual drivers access the device, yet. It only sets the way by introducing the layer. As per the proposed change, this is a preparation of the TPIU driver, so that we can convert the generic helper functions ( coresight_timeout()) more easily and keep the patch 05 easier for review (just like the Patch 4, which prepares the ETM driver). Cheers Suzuki > > I'm out of time for today - I will continue tomorrow. > > Regards, > Mathieu > >> >> /* Disable tpiu to support older devices */ >> - tpiu_disable_hw(drvdata); >> + tpiu_disable_hw(&desc.access); >> >> pdata = coresight_get_platform_data(dev); >> if (IS_ERR(pdata)) >> -- >> 2.24.1 >> _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2020-07-31 11:32 UTC|newest] Thread overview: 75+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-07-22 17:20 [RFC PATCH 00/14] coresight: Support for ETMv4.4 system instructions Suzuki K Poulose 2020-07-22 17:20 ` Suzuki K Poulose 2020-07-22 17:20 ` [RFC PATCH 01/14] coresight: etm4x: Skip save/restore before device registration Suzuki K Poulose 2020-07-22 17:20 ` Suzuki K Poulose 2020-07-29 18:01 ` Mathieu Poirier 2020-07-29 18:01 ` Mathieu Poirier 2020-07-30 14:45 ` Suzuki K Poulose 2020-07-30 14:45 ` Suzuki K Poulose 2020-07-22 17:20 ` [RFC PATCH 02/14] coresight: Introduce device access abstraction Suzuki K Poulose 2020-07-22 17:20 ` Suzuki K Poulose 2020-07-24 4:40 ` kernel test robot 2020-07-29 19:56 ` Mathieu Poirier 2020-07-29 19:56 ` Mathieu Poirier 2020-07-30 14:58 ` Suzuki K Poulose 2020-07-30 14:58 ` Suzuki K Poulose 2020-07-29 20:56 ` kernel test robot 2020-07-22 17:20 ` [RFC PATCH 03/14] coresight: tpiu: Use coresight " Suzuki K Poulose 2020-07-22 17:20 ` Suzuki K Poulose 2020-07-29 21:01 ` Mathieu Poirier 2020-07-29 21:01 ` Mathieu Poirier 2020-07-31 11:36 ` Suzuki K Poulose [this message] 2020-07-31 11:36 ` Suzuki K Poulose 2020-07-22 17:20 ` [RFC PATCH 04/14] coresight: etm4x: Free up argument of etm4_init_arch_data Suzuki K Poulose 2020-07-22 17:20 ` Suzuki K Poulose 2020-07-30 17:31 ` Mathieu Poirier 2020-07-30 17:31 ` Mathieu Poirier 2020-07-31 9:39 ` Suzuki K Poulose 2020-07-31 9:39 ` Suzuki K Poulose 2020-07-22 17:20 ` [RFC PATCH 05/14] coresight: Convert coresight_timeout to use access abstraction Suzuki K Poulose 2020-07-22 17:20 ` Suzuki K Poulose 2020-07-30 18:00 ` Mathieu Poirier 2020-07-30 18:00 ` Mathieu Poirier 2020-07-22 17:20 ` [RFC PATCH 06/14] coresight: Convert claim and lock operations to use access wrappers Suzuki K Poulose 2020-07-22 17:20 ` Suzuki K Poulose 2020-07-27 6:04 ` kernel test robot 2020-07-27 17:56 ` kernel test robot 2020-07-28 9:47 ` Suzuki K Poulose 2020-07-30 19:54 ` Mathieu Poirier 2020-07-30 19:54 ` Mathieu Poirier 2020-07-31 9:46 ` Suzuki K Poulose 2020-07-31 9:46 ` Suzuki K Poulose 2020-07-22 17:20 ` [RFC PATCH 07/14] coresight: etm4x: Always read the registers on the host CPU Suzuki K Poulose 2020-07-22 17:20 ` Suzuki K Poulose 2020-07-30 19:56 ` Mathieu Poirier 2020-07-30 19:56 ` Mathieu Poirier 2020-07-22 17:20 ` [RFC PATCH 08/14] coresight: etm4x: Convert all register accesses Suzuki K Poulose 2020-07-22 17:20 ` Suzuki K Poulose 2020-07-30 20:20 ` Mathieu Poirier 2020-07-30 20:20 ` Mathieu Poirier 2020-07-31 9:49 ` Suzuki K Poulose 2020-07-31 9:49 ` Suzuki K Poulose 2020-07-22 17:20 ` [RFC PATCH 09/14] coresight: etm4x: Add sysreg access helpers Suzuki K Poulose 2020-07-22 17:20 ` Suzuki K Poulose 2020-07-30 21:41 ` Mathieu Poirier 2020-07-30 21:41 ` Mathieu Poirier 2020-07-31 9:51 ` Suzuki K Poulose 2020-07-31 9:51 ` Suzuki K Poulose 2020-07-22 17:20 ` [RFC PATCH 10/14] coresight: etm4x: Define DEVARCH register fields Suzuki K Poulose 2020-07-22 17:20 ` Suzuki K Poulose 2020-07-22 17:20 ` [RFC PATCH 11/14] coresight: etm4x: Detect system register access support Suzuki K Poulose 2020-07-22 17:20 ` Suzuki K Poulose 2020-07-22 17:20 ` [RFC PATCH 12/14] coresight: etm4x: Refactor probing routine Suzuki K Poulose 2020-07-22 17:20 ` Suzuki K Poulose 2020-07-22 17:20 ` [RFC PATCH 13/14] coresight: etm4x: Add support for sysreg only devices Suzuki K Poulose 2020-07-22 17:20 ` Suzuki K Poulose 2020-07-22 17:20 ` [RFC PATCH 14/14] dts: bindings: coresight: ETMv4.4 system register access only units Suzuki K Poulose 2020-07-22 17:20 ` Suzuki K Poulose 2020-07-23 17:27 ` Rob Herring 2020-07-23 17:27 ` Rob Herring 2020-07-29 17:20 ` Mathieu Poirier 2020-07-29 17:20 ` Mathieu Poirier 2020-07-30 16:38 ` Suzuki K Poulose 2020-07-30 16:38 ` Suzuki K Poulose 2020-08-10 20:14 ` Mathieu Poirier 2020-08-10 20:14 ` Mathieu Poirier
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