[PATCH 26/31] coresight: etm4x: Run arch feature detection on the CPU

[Mathieu Poirier]

From: Suzuki K Poulose <suzuki.poulose at arm.com>

As we are about to add support for system register based devices,
we don't get an AMBA pid. So, the detection code could check
the system registers running on the CPU to check for the architecture
specific features. Thus we move the arch feature detection to
run on the CPU. We cannot always read the PID from the HW, as the
PID could be overridden by DT for broken devices. So, use the
PID from AMBA layer if available.

Cc: Mathieu Poirier <mathieu.poirier at linaro.org>
Cc: Mike Leach <mike.leach at linaro.org>
Cc: liuqi115 at huawei.com
Signed-off-by: Suzuki K Poulose <suzuki.poulose at arm.com>
Link: https://lore.kernel.org/r/20210110224850.1880240-25-suzuki.poulose@arm.com
Signed-off-by: Mathieu Poirier <mathieu.poirier at linaro.org>
---
 drivers/hwtracing/coresight/coresight-etm4x-core.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c
index c3e458af618a..fc26ecbc2d87 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x-core.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c
@@ -60,6 +60,7 @@ static u64 etm4_get_access_type(struct etmv4_config *config);
 static enum cpuhp_state hp_online;
 
 struct etm4_init_arg {
+	unsigned int		pid;
 	struct etmv4_drvdata	*drvdata;
 	struct csdev_access	*csa;
 };
@@ -884,6 +885,8 @@ static void etm4_init_arch_data(void *info)
 	etm4_os_unlock_csa(drvdata, csa);
 	etm4_cs_unlock(drvdata, csa);
 
+	etm4_check_arch_features(drvdata, init_arg->pid);
+
 	/* find all capabilities of the tracing unit */
 	etmidr0 = etm4x_relaxed_read32(csa, TRCIDR0);
 
@@ -1750,6 +1753,7 @@ static int etm4_probe(struct device *dev, void __iomem *base, u32 etm_pid)
 
 	init_arg.drvdata = drvdata;
 	init_arg.csa = &desc.access;
+	init_arg.pid = etm_pid;
 
 	if (smp_call_function_single(drvdata->cpu,
 				etm4_init_arch_data,  &init_arg, 1))
@@ -1794,8 +1798,6 @@ static int etm4_probe(struct device *dev, void __iomem *base, u32 etm_pid)
 		drvdata->boot_enable = true;
 	}
 
-	etm4_check_arch_features(drvdata, etm_pid);
-
 	return 0;
 }
 
-- 
2.25.1