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-rw-r--r--drivers/hwtracing/coresight/coresight-priv.h7
-rw-r--r--drivers/hwtracing/coresight/coresight.c86
2 files changed, 93 insertions, 0 deletions
diff --git a/drivers/hwtracing/coresight/coresight-priv.h b/drivers/hwtracing/coresight/coresight-priv.h
index c11da5564a67..579f34943bf1 100644
--- a/drivers/hwtracing/coresight/coresight-priv.h
+++ b/drivers/hwtracing/coresight/coresight-priv.h
@@ -25,6 +25,13 @@
#define CORESIGHT_DEVID 0xfc8
#define CORESIGHT_DEVTYPE 0xfcc
+
+/*
+ * Coresight device CLAIM protocol.
+ * See PSCI - ARM DEN 0022D, Section: 6.8.1 Debug and Trace save and restore.
+ */
+#define CORESIGHT_CLAIM_SELF_HOSTED BIT(1)
+
#define TIMEOUT_US 100
#define BMVAL(val, lsb, msb) ((val & GENMASK(msb, lsb)) >> lsb)
diff --git a/drivers/hwtracing/coresight/coresight.c b/drivers/hwtracing/coresight/coresight.c
index f4f50753cf75..2b0df1a0a8df 100644
--- a/drivers/hwtracing/coresight/coresight.c
+++ b/drivers/hwtracing/coresight/coresight.c
@@ -128,6 +128,92 @@ static int coresight_find_link_outport(struct coresight_device *csdev,
return -ENODEV;
}
+static inline u32 coresight_read_claim_tags(void __iomem *base)
+{
+ return readl_relaxed(base + CORESIGHT_CLAIMCLR);
+}
+
+static inline bool coresight_is_claimed_self_hosted(void __iomem *base)
+{
+ return coresight_read_claim_tags(base) == CORESIGHT_CLAIM_SELF_HOSTED;
+}
+
+static inline bool coresight_is_claimed_any(void __iomem *base)
+{
+ return coresight_read_claim_tags(base) != 0;
+}
+
+static inline void coresight_set_claim_tags(void __iomem *base)
+{
+ writel_relaxed(CORESIGHT_CLAIM_SELF_HOSTED, base + CORESIGHT_CLAIMSET);
+ isb();
+}
+
+static inline void coresight_clear_claim_tags(void __iomem *base)
+{
+ writel_relaxed(CORESIGHT_CLAIM_SELF_HOSTED, base + CORESIGHT_CLAIMCLR);
+ isb();
+}
+
+/*
+ * coresight_claim_device_unlocked : Claim the device for self-hosted usage
+ * to prevent an external tool from touching this device. As per PSCI
+ * standards, section "Preserving the execution context" => "Debug and Trace
+ * save and Restore", DBGCLAIM[1] is reserved for Self-hosted debug/trace and
+ * DBGCLAIM[0] is reserved for external tools.
+ *
+ * Called with CS_UNLOCKed for the component.
+ * Returns : 0 on success
+ */
+int coresight_claim_device_unlocked(void __iomem *base)
+{
+ if (coresight_is_claimed_any(base))
+ return -EBUSY;
+
+ coresight_set_claim_tags(base);
+ if (coresight_is_claimed_self_hosted(base))
+ return 0;
+ /* There was a race setting the tags, clean up and fail */
+ coresight_clear_claim_tags(base);
+ return -EBUSY;
+}
+
+int coresight_claim_device(void __iomem *base)
+{
+ int rc;
+
+ CS_UNLOCK(base);
+ rc = coresight_claim_device_unlocked(base);
+ CS_LOCK(base);
+
+ return rc;
+}
+
+/*
+ * coresight_disclaim_device_unlocked : Clear the claim tags for the device.
+ * Called with CS_UNLOCKed for the component.
+ */
+void coresight_disclaim_device_unlocked(void __iomem *base)
+{
+
+ if (coresight_is_claimed_self_hosted(base))
+ coresight_clear_claim_tags(base);
+ else
+ /*
+ * The external agent may have not honoured our claim
+ * and has manipulated it. Or something else has seriously
+ * gone wrong in our driver.
+ */
+ WARN_ON_ONCE(1);
+}
+
+void coresight_disclaim_device(void __iomem *base)
+{
+ CS_UNLOCK(base);
+ coresight_disclaim_device_unlocked(base);
+ CS_LOCK(base);
+}
+
static int coresight_enable_sink(struct coresight_device *csdev,
u32 mode, void *data)
{