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[68.147.8.254]) by smtp.gmail.com with ESMTPSA id zd17sm2684818igc.8.2016.04.26.15.10.59 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Tue, 26 Apr 2016 15:11:00 -0700 (PDT) From: Mathieu Poirier To: linux-arm-kernel@lists.infradead.org, Suzuki.Poulose@arm.com Cc: linux-kernel@vger.kernel.org Subject: [PATCH V4 13/18] coresight: tmc: make sysFS and Perf mode mutually exclusive Date: Tue, 26 Apr 2016 16:10:29 -0600 Message-Id: <1461708634-6327-14-git-send-email-mathieu.poirier@linaro.org> X-Mailer: git-send-email 2.5.0 In-Reply-To: <1461708634-6327-1-git-send-email-mathieu.poirier@linaro.org> References: <1461708634-6327-1-git-send-email-mathieu.poirier@linaro.org> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The sysFS and Perf access methods can't be allowed to interfere with one another. As such introducing guards to access functions that prevents moving forward if a TMC is already being used. Signed-off-by: Mathieu Poirier --- drivers/hwtracing/coresight/coresight-tmc-etf.c | 60 +++++++++++++++++++++++- drivers/hwtracing/coresight/coresight-tmc-etr.c | 62 +++++++++++++++++++++++-- 2 files changed, 117 insertions(+), 5 deletions(-) -- 2.5.0 diff --git a/drivers/hwtracing/coresight/coresight-tmc-etf.c b/drivers/hwtracing/coresight/coresight-tmc-etf.c index b5e5e6ac67eb..b11c52be54a9 100644 --- a/drivers/hwtracing/coresight/coresight-tmc-etf.c +++ b/drivers/hwtracing/coresight/coresight-tmc-etf.c @@ -111,7 +111,7 @@ static void tmc_etf_disable_hw(struct tmc_drvdata *drvdata) CS_LOCK(drvdata->base); } -static int tmc_enable_etf_sink(struct coresight_device *csdev, u32 mode) +static int tmc_enable_etf_sink_sysfs(struct coresight_device *csdev, u32 mode) { int ret = 0; bool used = false; @@ -185,6 +185,54 @@ out: return ret; } +static int tmc_enable_etf_sink_perf(struct coresight_device *csdev, u32 mode) +{ + int ret = 0; + long val; + unsigned long flags; + struct tmc_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent); + + /* This shouldn't be happening */ + if (WARN_ON(mode != CS_MODE_PERF)) + return -EINVAL; + + spin_lock_irqsave(&drvdata->spinlock, flags); + if (drvdata->reading) { + ret = -EINVAL; + goto out; + } + + val = local_xchg(&drvdata->mode, mode); + /* + * In Perf mode there can be only one writer per sink. There + * is also no need to continue if the ETB/ETR is already operated + * from sysFS. + */ + if (val != CS_MODE_DISABLED) { + ret = -EINVAL; + goto out; + } + + tmc_etb_enable_hw(drvdata); +out: + spin_unlock_irqrestore(&drvdata->spinlock, flags); + + return ret; +} + +static int tmc_enable_etf_sink(struct coresight_device *csdev, u32 mode) +{ + switch (mode) { + case CS_MODE_SYSFS: + return tmc_enable_etf_sink_sysfs(csdev, mode); + case CS_MODE_PERF: + return tmc_enable_etf_sink_perf(csdev, mode); + } + + /* We shouldn't be here */ + return -EINVAL; +} + static void tmc_disable_etf_sink(struct coresight_device *csdev) { long val; @@ -267,6 +315,7 @@ const struct coresight_ops tmc_etf_cs_ops = { int tmc_read_prepare_etb(struct tmc_drvdata *drvdata) { + long val; enum tmc_mode mode; int ret = 0; unsigned long flags; @@ -290,6 +339,13 @@ int tmc_read_prepare_etb(struct tmc_drvdata *drvdata) goto out; } + val = local_read(&drvdata->mode); + /* Don't interfere if operated from Perf */ + if (val == CS_MODE_PERF) { + ret = -EINVAL; + goto out; + } + /* If drvdata::buf is NULL the trace data has been read already */ if (drvdata->buf == NULL) { ret = -EINVAL; @@ -297,7 +353,7 @@ int tmc_read_prepare_etb(struct tmc_drvdata *drvdata) } /* Disable the TMC if need be */ - if (local_read(&drvdata->mode) == CS_MODE_SYSFS) + if (val == CS_MODE_SYSFS) tmc_etb_disable_hw(drvdata); drvdata->reading = true; diff --git a/drivers/hwtracing/coresight/coresight-tmc-etr.c b/drivers/hwtracing/coresight/coresight-tmc-etr.c index 7208584d0da7..847d1b5f2c13 100644 --- a/drivers/hwtracing/coresight/coresight-tmc-etr.c +++ b/drivers/hwtracing/coresight/coresight-tmc-etr.c @@ -87,7 +87,7 @@ static void tmc_etr_disable_hw(struct tmc_drvdata *drvdata) CS_LOCK(drvdata->base); } -static int tmc_enable_etr_sink(struct coresight_device *csdev, u32 mode) +static int tmc_enable_etr_sink_sysfs(struct coresight_device *csdev, u32 mode) { int ret = 0; bool used = false; @@ -165,6 +165,54 @@ out: return ret; } +static int tmc_enable_etr_sink_perf(struct coresight_device *csdev, u32 mode) +{ + int ret = 0; + long val; + unsigned long flags; + struct tmc_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent); + + /* This shouldn't be happening */ + if (WARN_ON(mode != CS_MODE_PERF)) + return -EINVAL; + + spin_lock_irqsave(&drvdata->spinlock, flags); + if (drvdata->reading) { + ret = -EINVAL; + goto out; + } + + val = local_xchg(&drvdata->mode, mode); + /* + * In Perf mode there can be only one writer per sink. There + * is also no need to continue if the ETR is already operated + * from sysFS. + */ + if (val != CS_MODE_DISABLED) { + ret = -EINVAL; + goto out; + } + + tmc_etr_enable_hw(drvdata); +out: + spin_unlock_irqrestore(&drvdata->spinlock, flags); + + return ret; +} + +static int tmc_enable_etr_sink(struct coresight_device *csdev, u32 mode) +{ + switch (mode) { + case CS_MODE_SYSFS: + return tmc_enable_etr_sink_sysfs(csdev, mode); + case CS_MODE_PERF: + return tmc_enable_etr_sink_perf(csdev, mode); + } + + /* We shouldn't be here */ + return -EINVAL; +} + static void tmc_disable_etr_sink(struct coresight_device *csdev) { long val; @@ -199,6 +247,7 @@ const struct coresight_ops tmc_etr_cs_ops = { int tmc_read_prepare_etr(struct tmc_drvdata *drvdata) { int ret = 0; + long val; unsigned long flags; /* config types are set a boot time and never change */ @@ -211,6 +260,13 @@ int tmc_read_prepare_etr(struct tmc_drvdata *drvdata) goto out; } + val = local_read(&drvdata->mode); + /* Don't interfere if operated from Perf */ + if (val == CS_MODE_PERF) { + ret = -EINVAL; + goto out; + } + /* If drvdata::buf is NULL the trace data has been read already */ if (drvdata->buf == NULL) { ret = -EINVAL; @@ -218,14 +274,14 @@ int tmc_read_prepare_etr(struct tmc_drvdata *drvdata) } /* Disable the TMC if need be */ - if (local_read(&drvdata->mode) == CS_MODE_SYSFS) + if (val == CS_MODE_SYSFS) tmc_etr_disable_hw(drvdata); drvdata->reading = true; out: spin_unlock_irqrestore(&drvdata->spinlock, flags); - return 0; + return ret; } int tmc_read_unprepare_etr(struct tmc_drvdata *drvdata)