[PATCH 1/2] lib: sbi: hart: Detect existence of cycle and instret CSRs for Zicntr

[Yao Zi]

Zicntr extension specifies three RO CSRs, time, cycle and instret. It
isn't precise to report Zicntr is fully supported with only time CSR
detected.

Since CSR emulating code only cares about the availablity of time CSR,
add additional definitions to represent the existance of cycle and
instret CSRs.

Signed-off-by: Yao Zi <ziyao at disroot.org>
---
 include/sbi/sbi_hart.h |  8 ++++++--
 lib/sbi/sbi_hart.c     | 30 ++++++++++++++++++++++--------
 lib/sbi/sbi_timer.c    |  2 +-
 3 files changed, 29 insertions(+), 11 deletions(-)

diff --git a/include/sbi/sbi_hart.h b/include/sbi/sbi_hart.h
index 4c36c77..0a740cf 100644
--- a/include/sbi/sbi_hart.h
+++ b/include/sbi/sbi_hart.h
@@ -37,8 +37,12 @@ enum sbi_hart_extensions {
 	SBI_HART_EXT_SSCOFPMF,
 	/** HART has Sstc extension */
 	SBI_HART_EXT_SSTC,
-	/** HART has Zicntr extension (i.e. HW cycle, time & instret CSRs) */
-	SBI_HART_EXT_ZICNTR,
+	/** HART has HW time CSR, as specified in Zicntr extension */
+	SBI_HART_EXT_ZICNTR_TIME,
+	/** HART has HW cycle CSR, as specified in Zicntr extension */
+	SBI_HART_EXT_ZICNTR_CYCLE,
+	/** HART has HW instret CSR, as specified in Zicntr extension */
+	SBI_HART_EXT_ZICNTR_INSTRET,
 	/** HART has Zihpm extension */
 	SBI_HART_EXT_ZIHPM,
 	/** HART has Zkr extension */
diff --git a/lib/sbi/sbi_hart.c b/lib/sbi/sbi_hart.c
index 8e2979b..e1d630d 100644
--- a/lib/sbi/sbi_hart.c
+++ b/lib/sbi/sbi_hart.c
@@ -669,7 +669,9 @@ const struct sbi_hart_ext_data sbi_hart_ext[] = {
 	__SBI_HART_EXT_DATA(smstateen, SBI_HART_EXT_SMSTATEEN),
 	__SBI_HART_EXT_DATA(sscofpmf, SBI_HART_EXT_SSCOFPMF),
 	__SBI_HART_EXT_DATA(sstc, SBI_HART_EXT_SSTC),
-	__SBI_HART_EXT_DATA(zicntr, SBI_HART_EXT_ZICNTR),
+	__SBI_HART_EXT_DATA(zicntr_time, SBI_HART_EXT_ZICNTR_TIME),
+	__SBI_HART_EXT_DATA(zicntr_cycle, SBI_HART_EXT_ZICNTR_CYCLE),
+	__SBI_HART_EXT_DATA(zicntr_instret, SBI_HART_EXT_ZICNTR_INSTRET),
 	__SBI_HART_EXT_DATA(zihpm, SBI_HART_EXT_ZIHPM),
 	__SBI_HART_EXT_DATA(zkr, SBI_HART_EXT_ZKR),
 	__SBI_HART_EXT_DATA(smcntrpmf, SBI_HART_EXT_SMCNTRPMF),
@@ -782,7 +784,7 @@ static int hart_detect_features(struct sbi_scratch *scratch)
 	struct sbi_hart_features *hfeatures =
 		sbi_scratch_offset_ptr(scratch, hart_features_offset);
 	unsigned long val, oldval;
-	bool has_zicntr = false;
+	bool has_time = false, has_cycle = false, has_instret = false;
 	int rc;
 
 	/* If hart features already detected then do nothing */
@@ -919,7 +921,13 @@ __pmp_skip:
 			CSR_SCOUNTOVF, SBI_HART_EXT_SSCOFPMF);
 	/* Detect if hart supports time CSR */
 	__check_ext_csr(SBI_HART_PRIV_VER_UNKNOWN,
-			CSR_TIME, SBI_HART_EXT_ZICNTR);
+			CSR_TIME, SBI_HART_EXT_ZICNTR_TIME);
+	/* Detect if hart supports cycle CSR */
+	__check_ext_csr(SBI_HART_PRIV_VER_UNKNOWN,
+			CSR_CYCLE, SBI_HART_EXT_ZICNTR_CYCLE);
+	/* Detect if hart supports instret CSR */
+	__check_ext_csr(SBI_HART_PRIV_VER_UNKNOWN,
+			CSR_INSTRET, SBI_HART_EXT_ZICNTR_INSTRET);
 	/* Detect if hart has AIA local interrupt CSRs */
 	__check_ext_csr(SBI_HART_PRIV_VER_UNKNOWN,
 			CSR_MTOPI, SBI_HART_EXT_SMAIA);
@@ -938,8 +946,10 @@ __pmp_skip:
 
 #undef __check_ext_csr
 
-	/* Save trap based detection of Zicntr */
-	has_zicntr = sbi_hart_has_extension(scratch, SBI_HART_EXT_ZICNTR);
+	/* Save trap based detection of Zicntr CSRs */
+	has_time = sbi_hart_has_extension(scratch, SBI_HART_EXT_ZICNTR_TIME);
+	has_cycle = sbi_hart_has_extension(scratch, SBI_HART_EXT_ZICNTR_CYCLE);
+	has_instret = sbi_hart_has_extension(scratch, SBI_HART_EXT_ZICNTR_INSTRET);
 
 	/* Let platform populate extensions */
 	rc = sbi_platform_extensions_init(sbi_platform_thishart_ptr(),
@@ -947,9 +957,13 @@ __pmp_skip:
 	if (rc)
 		return rc;
 
-	/* Zicntr should only be detected using traps */
-	__sbi_hart_update_extension(hfeatures, SBI_HART_EXT_ZICNTR,
-				    has_zicntr);
+	/* Zicntr CSRs should only be detected using traps */
+	__sbi_hart_update_extension(hfeatures, SBI_HART_EXT_ZICNTR_TIME,
+				    has_time);
+	__sbi_hart_update_extension(hfeatures, SBI_HART_EXT_ZICNTR_CYCLE,
+				    has_cycle);
+	__sbi_hart_update_extension(hfeatures, SBI_HART_EXT_ZICNTR_INSTRET,
+				    has_instret);
 
 	/* Extensions implied by other extensions and features */
 	if (hfeatures->mhpm_mask)
diff --git a/lib/sbi/sbi_timer.c b/lib/sbi/sbi_timer.c
index 86e0db5..b4db4ca 100644
--- a/lib/sbi/sbi_timer.c
+++ b/lib/sbi/sbi_timer.c
@@ -190,7 +190,7 @@ int sbi_timer_init(struct sbi_scratch *scratch, bool cold_boot)
 		if (!time_delta_off)
 			return SBI_ENOMEM;
 
-		if (sbi_hart_has_extension(scratch, SBI_HART_EXT_ZICNTR))
+		if (sbi_hart_has_extension(scratch, SBI_HART_EXT_ZICNTR_TIME))
 			get_time_val = get_ticks;
 
 		ret = sbi_platform_timer_init(plat);
-- 
2.48.1