struct csdev_access *csa)
{
u32 devarch = readl_relaxed(drvdata->base + TRCDEVARCH);
- u32 idr1 = readl_relaxed(drvdata->base + TRCIDR1);
/*
* All ETMs must implement TRCDEVARCH to indicate that
- * the component is an ETMv4. To support any broken
- * implementations we fall back to TRCIDR1 check, which
- * is not really reliable.
+ * the component is an ETMv4. Even though TRCIDR1 also
+ * contains the information, it is part of the "Trace"
+ * register and must be accessed with the OSLK cleared,
+ * with MMIO. But we cannot touch the OSLK until we are
+ * sure this is an ETM. So rely only on the TRCDEVARCH.
*/
- if ((devarch & ETM_DEVARCH_ID_MASK) == ETM_DEVARCH_ETMv4x_ARCH) {
- drvdata->arch = etm_devarch_to_arch(devarch);
- } else {
- pr_warn("CPU%d: ETM4x incompatible TRCDEVARCH: %x, falling back to TRCIDR1\n",
- smp_processor_id(), devarch);
-
- if (ETM_TRCIDR1_ARCH_MAJOR(idr1) != ETM_TRCIDR1_ARCH_ETMv4)
- return false;
- drvdata->arch = etm_trcidr_to_arch(idr1);
+ if ((devarch & ETM_DEVARCH_ID_MASK) != ETM_DEVARCH_ETMv4x_ARCH) {
+ pr_warn_once("TRCDEVARCH doesn't match ETMv4 architecture\n");
+ return false;
}
+ drvdata->arch = etm_devarch_to_arch(devarch);
*csa = CSDEV_ACCESS_IOMEM(drvdata->base);
return true;
}
* TRCDEVARCH - CoreSight architected register
* - Bits[15:12] - Major version
* - Bits[19:16] - Minor version
- * TRCIDR1 - ETM architected register
- * - Bits[11:8] - Major version
- * - Bits[7:4] - Minor version
- * We must rely on TRCDEVARCH for the version information,
- * however we don't want to break the support for potential
- * old implementations which might not implement it. Thus
- * we fall back to TRCIDR1 if TRCDEVARCH is not implemented
- * for memory mapped components.
+ *
+ * We must rely only on TRCDEVARCH for the version information. Even though,
+ * TRCIDR1 also provides the architecture version, it is a "Trace" register
+ * and as such must be accessed only with Trace power domain ON. This may
+ * not be available at probe time.
+ *
* Now to make certain decisions easier based on the version
* we use an internal representation of the version in the
* driver, as follows :
ETM_DEVARCH_REVISION(devarch));
}
-static inline u8 etm_trcidr_to_arch(u32 trcidr1)
-{
- return ETM_ARCH_VERSION(ETM_TRCIDR1_ARCH_MAJOR(trcidr1),
- ETM_TRCIDR1_ARCH_MINOR(trcidr1));
-}
-
enum etm_impdef_type {
ETM4_IMPDEF_HISI_CORE_COMMIT,
ETM4_IMPDEF_FEATURE_MAX,