[PATCH v7 18/28] coresight: etm4x: Detect access early on the target CPU

[Suzuki K Poulose]

In preparation to detect the support for system instruction
support, move the detection of the device access to the target
CPU.

Cc: Mike Leach <mike.le...@linaro.org>
Reviewed-by: Mathieu Poirier <mathieu.poir...@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poul...@arm.com>
---
Changes since v3
 - Name constructs etm4_xx instead of etm_** (Mathieu)
---
 .../coresight/coresight-etm4x-core.c          | 45 ++++++++++++++++---
 1 file changed, 40 insertions(+), 5 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c 
b/drivers/hwtracing/coresight/coresight-etm4x-core.c
index 862b424aef26..7adc9bd03eb5 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x-core.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c
@@ -59,6 +59,11 @@ static u64 etm4_get_access_type(struct etmv4_config *config);
 
 static enum cpuhp_state hp_online;
 
+struct etm4_init_arg {
+       struct etmv4_drvdata    *drvdata;
+       struct csdev_access     *csa;
+};
+
 /*
  * Check if TRCSSPCICRn(i) is implemented for a given instance.
  *
@@ -776,6 +781,22 @@ static const struct coresight_ops etm4_cs_ops = {
        .source_ops     = &etm4_source_ops,
 };
 
+static bool etm4_init_iomem_access(struct etmv4_drvdata *drvdata,
+                                  struct csdev_access *csa)
+{
+       *csa = CSDEV_ACCESS_IOMEM(drvdata->base);
+       return true;
+}
+
+static bool etm4_init_csdev_access(struct etmv4_drvdata *drvdata,
+                                  struct csdev_access *csa)
+{
+       if (drvdata->base)
+               return etm4_init_iomem_access(drvdata, csa);
+
+       return false;
+}
+
 static void etm4_init_arch_data(void *info)
 {
        u32 etmidr0;
@@ -784,11 +805,22 @@ static void etm4_init_arch_data(void *info)
        u32 etmidr3;
        u32 etmidr4;
        u32 etmidr5;
-       struct etmv4_drvdata *drvdata = info;
-       struct csdev_access tmp_csa = CSDEV_ACCESS_IOMEM(drvdata->base);
-       struct csdev_access *csa = &tmp_csa;
+       struct etm4_init_arg *init_arg = info;
+       struct etmv4_drvdata *drvdata;
+       struct csdev_access *csa;
        int i;
 
+       drvdata = init_arg->drvdata;
+       csa = init_arg->csa;
+
+       /*
+        * If we are unable to detect the access mechanism,
+        * or unable to detect the trace unit type, fail
+        * early.
+        */
+       if (!etm4_init_csdev_access(drvdata, csa))
+               return;
+
        /* Make sure all registers are accessible */
        etm4_os_unlock_csa(drvdata, csa);
        etm4_cs_unlock(drvdata, csa);
@@ -1634,6 +1666,7 @@ static int etm4_probe(struct amba_device *adev, const 
struct amba_id *id)
        struct etmv4_drvdata *drvdata;
        struct resource *res = &adev->res;
        struct coresight_desc desc = { 0 };
+       struct etm4_init_arg init_arg = { 0 };
 
        drvdata = devm_kzalloc(dev, sizeof(*drvdata), GFP_KERNEL);
        if (!drvdata)
@@ -1661,7 +1694,6 @@ static int etm4_probe(struct amba_device *adev, const 
struct amba_id *id)
                return PTR_ERR(base);
 
        drvdata->base = base;
-       desc.access = CSDEV_ACCESS_IOMEM(base);
 
        spin_lock_init(&drvdata->spinlock);
 
@@ -1673,8 +1705,11 @@ static int etm4_probe(struct amba_device *adev, const 
struct amba_id *id)
        if (!desc.name)
                return -ENOMEM;
 
+       init_arg.drvdata = drvdata;
+       init_arg.csa = &desc.access;
+
        if (smp_call_function_single(drvdata->cpu,
-                               etm4_init_arch_data,  drvdata, 1))
+                               etm4_init_arch_data,  &init_arg, 1))
                dev_err(dev, "ETM arch init failed\n");
 
        if (etm4_arch_supported(drvdata->arch) == false)
-- 
2.24.1