coresight: tmc: adding mode of operation for link/sinks

[firefly-linux-kernel-4.4.55.git] / drivers / hwtracing / coresight / coresight-tmc-etf.c

diff --git a/drivers/hwtracing/coresight/coresight-tmc-etf.c b/drivers/hwtracing/coresight/coresight-tmc-etf.c
index 60edf4d1968f2890af9bf86ca041cfbf83456c95..bc0efc1e5b49dc4eec534f90e7eee12adf1eb968 100644 (file)
--- a/drivers/hwtracing/coresight/coresight-tmc-etf.c
+++ b/drivers/hwtracing/coresight/coresight-tmc-etf.c
@@ -111,6 +111,7 @@ static int tmc_enable_etf_sink(struct coresight_device *csdev, u32 mode)
        int ret = 0;
        bool used = false;
        char *buf = NULL;
+       long val;
        unsigned long flags;
        struct tmc_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
 
@@ -140,6 +141,15 @@ static int tmc_enable_etf_sink(struct coresight_device *csdev, u32 mode)
                goto out;
        }
 
+       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.
@@ -157,7 +167,6 @@ static int tmc_enable_etf_sink(struct coresight_device *csdev, u32 mode)
        }
 
        tmc_etb_enable_hw(drvdata);
-       drvdata->enable = true;
 out:
        spin_unlock_irqrestore(&drvdata->spinlock, flags);
 
@@ -173,6 +182,7 @@ out:
 
 static void tmc_disable_etf_sink(struct coresight_device *csdev)
 {
+       long val;
        unsigned long flags;
        struct tmc_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
 
@@ -182,8 +192,11 @@ 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");
@@ -202,7 +215,7 @@ 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");
@@ -222,7 +235,7 @@ 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");
@@ -279,7 +292,7 @@ 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;
@@ -310,7 +323,7 @@ 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