ptm: tegra210: start/stop PTM by SMP cross call

When PTM is configured, if register value are written to each
CPU's PTM aperture in memory map, it will not work if that CPU
is powered down.

Instead, registers are updated in SMP cross call, which will
wake up CPU by sending IPI if it's power gated. This guarantees
the PTM registers for each CPU are configured properly.

Once the initial configuration is done, subsequent power gating
cycles won't affect it since PTM context save and restore are
done at C7 entry and exit point.

Change-Id: I2fee0553ba8e26360d59af15a3b99b6b11771574
Signed-off-by: Bo Yan <byan@nvidia.com>
Reviewed-on: http://git-master/r/679226
Reviewed-by: Automatic_Commit_Validation_User
GVS: Gerrit_Virtual_Submit
Reviewed-by: Mitch Luban <mluban@nvidia.com>

diff --git a/drivers/platform/tegra/tegra_ptm_t210.c b/drivers/platform/tegra/tegra_ptm_t210.c
index 96420796f5e2fd2f86ace9bce57a9d458dae86c4..67000bcbb317bdb479271cffdc76d9dfb11c3f8b 100644 (file)
--- a/drivers/platform/tegra/tegra_ptm_t210.c
+++ b/drivers/platform/tegra/tegra_ptm_t210.c
@@ -297,10 +297,14 @@ static void ptm_restore(struct tracectx *t)
 }
 
 /* Initialise the PTM registers */
-static void ptm_init(struct tracectx *t, int id)
+static void ptm_init(void *p_info)
 {
+       u32 id, level_val, addr_mask;
        int trccfg, i;
-       u32 level_val, addr_mask;
+       struct tracectx *t;
+
+       t = (struct tracectx *)p_info;
+       id = raw_smp_processor_id();
 
        /* Power up the CPU PTM */
        ptm_writel(t, id, 8, TRCPDCR);
@@ -458,6 +462,8 @@ static void ptm_init(struct tracectx *t, int id)
                        /* insert global timestamp if enabled */
                        ptm_writel(t, id, 0x3, TRCTSCTLR);
        }
+       ptm_writel(t, id, 1, TRCPRGCTLR);
+
        dev_dbg(t->dev, "PTM%d initialized.\n", id);
 }
 
@@ -606,14 +612,8 @@ static void etr_init(struct tracectx *t)
 /* This function enables PTM traces */
 static int trace_t210_start(struct tracectx *t)
 {
-       int id;
-
        clk_enable(csite_clk);
 
-       /* Programming PTM */
-       for_each_online_cpu(id)
-               ptm_init(t, id);
-
        if (t->ape) {
                /* Programming APE */
                ape_init(t);
@@ -642,9 +642,7 @@ static int trace_t210_start(struct tracectx *t)
                tpiu_init(t);
 
                /* Enabling the ETM */
-               for_each_online_cpu(id) {
-                       ptm_writel(t, id, 1, TRCPRGCTLR);
-               }
+               on_each_cpu(ptm_init, t, false);
                dsb(sy);
                isb();
        }
@@ -652,15 +650,20 @@ static int trace_t210_start(struct tracectx *t)
        return 0;
 }
 
+void ptm_disable(void *p_info)
+{
+       struct tracectx *t = (struct tracectx *)p_info;
+       u32 id = raw_smp_processor_id();
+
+       ptm_writel(t, id, 0, TRCPRGCTLR);
+}
+
 /* Disable the traces */
 static int trace_t210_stop(struct tracectx *t)
 {
-       int id;
-
        if (!t->ape)
                /* Disabling the ETM */
-               for_each_online_cpu(id)
-                       ptm_writel(t, id, 0, TRCPRGCTLR);
+               on_each_cpu(ptm_disable, &tracer, true);
        else
                /* Disable APE traces */
                ape_writel(t, 0x500, CORESIGHT_APE_CPU0_ETM_ETMCR_0);
@@ -799,11 +802,11 @@ static ssize_t trc_fill_buf(struct tracectx *t)
                overflow &= 0x01;
 
                /* Disabling the ETM */
-               for_each_online_cpu(count)
-                       ptm_writel(t, count, 0, TRCPRGCTLR);
-
-               ape_writel(t, 0x500, CORESIGHT_APE_CPU0_ETM_ETMCR_0);
-
+               if (t->enable) {
+                       on_each_cpu(ptm_disable, t, true);
+                       ape_writel(t, 0x500, CORESIGHT_APE_CPU0_ETM_ETMCR_0);
+                       t->enable = 0;
+               }
                t->buf_size = t->etr_buf - t->etr_address;
                t->etr_buf = t->etr_address;
                if (overflow) {
@@ -822,10 +825,11 @@ static ssize_t trc_fill_buf(struct tracectx *t)
                overflow &= 0x1;
 
                /* Disabling the ETM */
-               for_each_online_cpu(count)
-                       ptm_writel(t, count, 0, TRCPRGCTLR);
-
-               ape_writel(t, 0x500, CORESIGHT_APE_CPU0_ETM_ETMCR_0);
+               if (t->enable) {
+                       on_each_cpu(ptm_disable, t, true);
+                       ape_writel(t, 0x500, CORESIGHT_APE_CPU0_ETM_ETMCR_0);
+                       t->enable = 0;
+               }
 
                /* by default, start reading from 0 */
                t->buf_size = rwp;
@@ -909,12 +913,10 @@ static struct notifier_block ptm_cpu_pm_notifier_block = {
 static int ptm_cpu_hotplug_notifier(struct notifier_block *self,
        unsigned long action, void *hcpu)
 {
-       long cpu = (long)hcpu;
        switch (action) {
        case CPU_STARTING:
                if (tracer.enable) {
-                       ptm_init(&tracer, cpu);
-                       ptm_writel(&tracer, cpu, 1, TRCPRGCTLR);
+                       ptm_init(&tracer);
                }
                break;
        default:
@@ -1004,7 +1006,7 @@ static ssize_t trace_enable_store(struct kobject *kobj,
        const char *buf, size_t n)
 {
        unsigned int value;
-       int ret;
+       int ret = -EAGAIN;
 
        if (sscanf(buf, "%u", &value) != 1)
                return -EINVAL;
@@ -1015,16 +1017,19 @@ static ssize_t trace_enable_store(struct kobject *kobj,
        mutex_lock(&tracer.mutex);
 
        if (value) {
-               ret = trace_t210_start(&tracer);
+               if (!tracer.enable)
+                       ret = trace_t210_start(&tracer);
                tracer.enable = 1;
        } else {
-               ret = trace_t210_stop(&tracer);
-               tracer.enable = 0;
+               if (tracer.enable) {
+                       tracer.enable = 0;
+                       ret = trace_t210_stop(&tracer);
+               }
        }
 
        mutex_unlock(&tracer.mutex);
 
-       return ret ? : n;
+       return ret ? ret : n;
 }
 
 static ssize_t trace_range_address_store(struct kobject *kobj,