From: Suzuki Kuruppassery Poulose <suzuki.poulose@arm.com> To: Mathieu Poirier <mathieu.poirier@linaro.org>, Mike Leach <mike.leach@linaro.org> Cc: coresight@lists.linaro.org, linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org, linux-doc@vger.kernel.org Subject: Re: [PATCH v5 07/14] coresight: cti: Add device tree support for custom CTI. Date: Fri, 29 Nov 2019 14:16:33 +0000 [thread overview] Message-ID: <35357ff3-2b1e-764e-cfbd-65bcc7a4faa6@arm.com> (raw) In-Reply-To: <20191125212258.GB18542@xps15> On 25/11/2019 21:22, Mathieu Poirier wrote: > On Tue, Nov 19, 2019 at 11:19:05PM +0000, Mike Leach wrote: >> Adds support for CTIs whose connections are implementation defined at >> hardware design time, and not constrained by v8 architecture. >> >> These CTIs have no standard connection setup, all the settings have to >> be defined in the device tree files. The patch creates a set of connections >> and trigger signals based on the information provided. >> >> Signed-off-by: Mike Leach <mike.leach@linaro.org> >> --- >> .../coresight/coresight-cti-platform.c | 250 +++++++++++++++++- >> .../hwtracing/coresight/coresight-cti-sysfs.c | 11 + >> 2 files changed, 257 insertions(+), 4 deletions(-) >> +static int cti_plat_create_impdef_connections(struct device *dev, >> + struct cti_drvdata *drvdata) >> +{ >> + int rc = 0; >> + struct fwnode_handle *fwnode = dev_fwnode(dev); >> + struct fwnode_handle *child = NULL; >> + >> + if (IS_ERR_OR_NULL(fwnode)) >> + return -EINVAL; >> + >> + fwnode_for_each_child_node(fwnode, child) { >> + if (cti_plat_node_name_eq(child, CTI_DT_CONNS)) >> + rc = cti_plat_create_connection(dev, drvdata, child); >> + if (rc != 0) >> + break; >> + } >> + fwnode_handle_put(child); > > As far as I can tell we don't need to call fwnode_handle_put()? Actually we do, if we break the scan in between, at least for of_nodes. I had to literally look it down all the way down to confirm this. So for CONFIG_OF it ends up in of_get_next_available_child(), which drops the ref on "prev" and grabs the "next". So in case we break the loop, we must drop the ref on the child. Otherwise, the last result would be NULL, which would have dropped the ref on the "last" valid entry. And this is harmless with a NULL ptr. Suzuki
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From: Suzuki Kuruppassery Poulose <suzuki.poulose@arm.com> To: Mathieu Poirier <mathieu.poirier@linaro.org>, Mike Leach <mike.leach@linaro.org> Cc: devicetree@vger.kernel.org, coresight@lists.linaro.org, linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org Subject: Re: [PATCH v5 07/14] coresight: cti: Add device tree support for custom CTI. Date: Fri, 29 Nov 2019 14:16:33 +0000 [thread overview] Message-ID: <35357ff3-2b1e-764e-cfbd-65bcc7a4faa6@arm.com> (raw) In-Reply-To: <20191125212258.GB18542@xps15> On 25/11/2019 21:22, Mathieu Poirier wrote: > On Tue, Nov 19, 2019 at 11:19:05PM +0000, Mike Leach wrote: >> Adds support for CTIs whose connections are implementation defined at >> hardware design time, and not constrained by v8 architecture. >> >> These CTIs have no standard connection setup, all the settings have to >> be defined in the device tree files. The patch creates a set of connections >> and trigger signals based on the information provided. >> >> Signed-off-by: Mike Leach <mike.leach@linaro.org> >> --- >> .../coresight/coresight-cti-platform.c | 250 +++++++++++++++++- >> .../hwtracing/coresight/coresight-cti-sysfs.c | 11 + >> 2 files changed, 257 insertions(+), 4 deletions(-) >> +static int cti_plat_create_impdef_connections(struct device *dev, >> + struct cti_drvdata *drvdata) >> +{ >> + int rc = 0; >> + struct fwnode_handle *fwnode = dev_fwnode(dev); >> + struct fwnode_handle *child = NULL; >> + >> + if (IS_ERR_OR_NULL(fwnode)) >> + return -EINVAL; >> + >> + fwnode_for_each_child_node(fwnode, child) { >> + if (cti_plat_node_name_eq(child, CTI_DT_CONNS)) >> + rc = cti_plat_create_connection(dev, drvdata, child); >> + if (rc != 0) >> + break; >> + } >> + fwnode_handle_put(child); > > As far as I can tell we don't need to call fwnode_handle_put()? Actually we do, if we break the scan in between, at least for of_nodes. I had to literally look it down all the way down to confirm this. So for CONFIG_OF it ends up in of_get_next_available_child(), which drops the ref on "prev" and grabs the "next". So in case we break the loop, we must drop the ref on the child. Otherwise, the last result would be NULL, which would have dropped the ref on the "last" valid entry. And this is harmless with a NULL ptr. Suzuki _______________________________________________ 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:[~2019-11-29 14:16 UTC|newest] Thread overview: 124+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-11-19 23:18 [PATCH v5 00/14] CoreSight CTI Driver Mike Leach 2019-11-19 23:18 ` Mike Leach 2019-11-19 23:18 ` [PATCH v5 01/14] coresight: cti: Initial " Mike Leach 2019-11-19 23:18 ` Mike Leach 2019-11-21 20:21 ` Mathieu Poirier 2019-11-21 20:21 ` Mathieu Poirier 2019-11-29 12:05 ` Mike Leach 2019-11-29 12:05 ` Mike Leach 2019-12-03 16:53 ` Mathieu Poirier 2019-12-03 16:53 ` Mathieu Poirier 2019-11-25 19:03 ` Suzuki Kuruppassery Poulose 2019-11-25 19:03 ` Suzuki Kuruppassery Poulose 2019-11-29 12:06 ` Mike Leach 2019-11-29 12:06 ` Mike Leach 2019-11-19 23:19 ` [PATCH v5 02/14] coresight: cti: Add sysfs coresight mgmt reg access Mike Leach 2019-11-19 23:19 ` Mike Leach 2019-11-22 17:19 ` Mathieu Poirier 2019-11-22 17:19 ` Mathieu Poirier 2019-11-19 23:19 ` [PATCH v5 03/14] coresight: cti: Add sysfs access to program function regs Mike Leach 2019-11-19 23:19 ` Mike Leach 2019-11-27 18:26 ` Suzuki Kuruppassery Poulose 2019-11-27 18:26 ` Suzuki Kuruppassery Poulose 2019-11-29 12:47 ` Mike Leach 2019-11-29 12:47 ` Mike Leach 2019-11-28 10:54 ` Suzuki Kuruppassery Poulose 2019-11-28 10:54 ` Suzuki Kuruppassery Poulose 2019-11-28 17:20 ` Mathieu Poirier 2019-11-28 17:20 ` Mathieu Poirier 2019-11-28 18:00 ` Suzuki Kuruppassery Poulose 2019-11-28 18:00 ` Suzuki Kuruppassery Poulose 2019-11-29 12:50 ` Mike Leach 2019-11-29 12:50 ` Mike Leach 2019-11-19 23:19 ` [PATCH v5 04/14] coresight: cti: Add sysfs trigger / channel programming API Mike Leach 2019-11-19 23:19 ` Mike Leach 2019-11-22 18:40 ` Mathieu Poirier 2019-11-22 18:40 ` Mathieu Poirier 2019-11-27 18:40 ` Suzuki Kuruppassery Poulose 2019-11-27 18:40 ` Suzuki Kuruppassery Poulose 2019-11-29 13:01 ` Mike Leach 2019-11-29 13:01 ` Mike Leach 2019-11-19 23:19 ` [PATCH v5 05/14] dt-bindings: arm: Adds CoreSight CTI hardware definitions Mike Leach 2019-11-19 23:19 ` Mike Leach 2019-11-20 19:06 ` Mathieu Poirier 2019-11-20 19:06 ` Mathieu Poirier 2019-11-20 22:39 ` Mike Leach 2019-11-20 22:39 ` Mike Leach 2019-11-22 23:33 ` Rob Herring 2019-11-22 23:33 ` Rob Herring 2019-11-29 13:50 ` Mike Leach 2019-11-29 13:50 ` Mike Leach 2019-11-29 14:12 ` Suzuki Kuruppassery Poulose 2019-11-29 14:12 ` Suzuki Kuruppassery Poulose 2019-11-28 18:38 ` Suzuki Kuruppassery Poulose 2019-11-28 18:38 ` Suzuki Kuruppassery Poulose 2019-11-29 13:57 ` Mike Leach 2019-11-29 13:57 ` Mike Leach 2019-11-19 23:19 ` [PATCH v5 06/14] coresight: cti: Add device tree support for v8 arch CTI Mike Leach 2019-11-19 23:19 ` Mike Leach 2019-11-25 19:00 ` Mathieu Poirier 2019-11-25 19:00 ` Mathieu Poirier 2019-11-29 11:33 ` Suzuki Kuruppassery Poulose 2019-11-29 11:33 ` Suzuki Kuruppassery Poulose 2019-12-03 10:59 ` Mike Leach 2019-12-03 10:59 ` Mike Leach 2019-12-03 11:28 ` Suzuki Kuruppassery Poulose 2019-12-03 11:28 ` Suzuki Kuruppassery Poulose 2019-12-03 12:25 ` Mike Leach 2019-12-03 12:25 ` Mike Leach 2019-11-19 23:19 ` [PATCH v5 07/14] coresight: cti: Add device tree support for custom CTI Mike Leach 2019-11-19 23:19 ` Mike Leach 2019-11-25 21:22 ` Mathieu Poirier 2019-11-25 21:22 ` Mathieu Poirier 2019-11-29 14:16 ` Suzuki Kuruppassery Poulose [this message] 2019-11-29 14:16 ` Suzuki Kuruppassery Poulose 2019-11-29 21:11 ` Mathieu Poirier 2019-11-29 21:11 ` Mathieu Poirier 2019-11-29 14:18 ` Suzuki Kuruppassery Poulose 2019-11-29 14:18 ` Suzuki Kuruppassery Poulose 2019-12-03 14:05 ` Mike Leach 2019-12-03 14:05 ` Mike Leach 2019-11-19 23:19 ` [PATCH v5 08/14] coresight: cti: Enable CTI associated with devices Mike Leach 2019-11-19 23:19 ` Mike Leach 2019-11-25 22:45 ` Mathieu Poirier 2019-11-25 22:45 ` Mathieu Poirier 2019-12-05 16:33 ` Mike Leach 2019-12-05 16:33 ` Mike Leach 2019-11-29 18:28 ` Suzuki Kuruppassery Poulose 2019-11-29 18:28 ` Suzuki Kuruppassery Poulose 2019-11-29 21:25 ` Mathieu Poirier 2019-11-29 21:25 ` Mathieu Poirier 2019-12-05 16:33 ` Mike Leach 2019-12-05 16:33 ` Mike Leach 2019-11-19 23:19 ` [PATCH v5 09/14] coresight: cti: Add connection information to sysfs Mike Leach 2019-11-19 23:19 ` Mike Leach 2019-11-27 18:09 ` Mathieu Poirier 2019-11-27 18:09 ` Mathieu Poirier 2019-12-06 16:24 ` Mike Leach 2019-12-06 16:24 ` Mike Leach 2019-12-02 9:47 ` Suzuki Kuruppassery Poulose 2019-12-02 9:47 ` Suzuki Kuruppassery Poulose 2019-12-06 16:24 ` Mike Leach 2019-12-06 16:24 ` Mike Leach 2019-11-19 23:19 ` [PATCH v5 10/14] dt-bindings: qcom: Add CTI options for qcom msm8916 Mike Leach 2019-11-19 23:19 ` Mike Leach 2019-11-27 18:18 ` Mathieu Poirier 2019-11-27 18:18 ` Mathieu Poirier 2019-11-19 23:19 ` [PATCH v5 11/14] dt-bindings: arm: Juno platform - add CTI entries to device tree Mike Leach 2019-11-19 23:19 ` Mike Leach 2019-11-27 18:25 ` Mathieu Poirier 2019-11-27 18:25 ` Mathieu Poirier 2019-11-19 23:19 ` [PATCH v5 12/14] dt-bindings: hisilicon: Add CTI bindings for hi-6220 Mike Leach 2019-11-19 23:19 ` Mike Leach 2019-11-19 23:19 ` [PATCH v5 13/14] docs: coresight: Update documentation for CoreSight to cover CTI Mike Leach 2019-11-19 23:19 ` Mike Leach 2019-11-27 19:00 ` Mathieu Poirier 2019-11-27 19:00 ` Mathieu Poirier 2019-12-02 10:43 ` Suzuki Kuruppassery Poulose 2019-12-02 10:43 ` Suzuki Kuruppassery Poulose 2019-12-06 17:39 ` Mike Leach 2019-12-06 17:39 ` Mike Leach 2019-11-19 23:19 ` [PATCH v5 14/14] docs: sysfs: coresight: Add sysfs ABI documentation for CTI Mike Leach 2019-11-19 23:19 ` Mike Leach 2019-11-27 19:08 ` Mathieu Poirier 2019-11-27 19:08 ` Mathieu Poirier
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