cxl: Add tracepoints

This patch adds tracepoints throughout the cxl driver, which can provide
insight into:

- Context lifetimes
- Commands sent to the PSL and AFU and their completion status
- Segment and page table misses and their resolution
- PSL and AFU interrupts
- slbia calls from the powerpc copro_fault code

These tracepoints are mostly intended to aid in debugging (particularly
for new AFU designs), and may be useful standalone or in conjunction
with hardware traces collected by the PSL (read out via the trace
interface in debugfs) and AFUs.

Signed-off-by: Ian Munsie <imunsie@au1.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

1 files changed, 30 insertions, 8 deletions

diff --git a/drivers/misc/cxl/native.c b/drivers/misc/cxl/native.c
index 0f24fa5b0de3..29185fc61276 100644
--- a/drivers/misc/cxl/native.c
+++ b/drivers/misc/cxl/native.c
@@ -18,24 +18,28 @@
 #include <misc/cxl.h>
 
 #include "cxl.h"
+#include "trace.h"
 
 static int afu_control(struct cxl_afu *afu, u64 command,
 		       u64 result, u64 mask, bool enabled)
 {
 	u64 AFU_Cntl = cxl_p2n_read(afu, CXL_AFU_Cntl_An);
 	unsigned long timeout = jiffies + (HZ * CXL_TIMEOUT);
+	int rc = 0;
 
 	spin_lock(&afu->afu_cntl_lock);
 	pr_devel("AFU command starting: %llx\n", command);
 
+	trace_cxl_afu_ctrl(afu, command);
+
 	cxl_p2n_write(afu, CXL_AFU_Cntl_An, AFU_Cntl | command);
 
 	AFU_Cntl = cxl_p2n_read(afu, CXL_AFU_Cntl_An);
 	while ((AFU_Cntl & mask) != result) {
 		if (time_after_eq(jiffies, timeout)) {
 			dev_warn(&afu->dev, "WARNING: AFU control timed out!\n");
-			spin_unlock(&afu->afu_cntl_lock);
-			return -EBUSY;
+			rc = -EBUSY;
+			goto out;
 		}
 		pr_devel_ratelimited("AFU control... (0x%.16llx)\n",
 				     AFU_Cntl | command);
@@ -44,9 +48,11 @@ static int afu_control(struct cxl_afu *afu, u64 command,
 	};
 	pr_devel("AFU command complete: %llx\n", command);
 	afu->enabled = enabled;
+out:
+	trace_cxl_afu_ctrl_done(afu, command, rc);
 	spin_unlock(&afu->afu_cntl_lock);
 
-	return 0;
+	return rc;
 }
 
 static int afu_enable(struct cxl_afu *afu)
@@ -91,6 +97,9 @@ int cxl_psl_purge(struct cxl_afu *afu)
 	u64 dsisr, dar;
 	u64 start, end;
 	unsigned long timeout = jiffies + (HZ * CXL_TIMEOUT);
+	int rc = 0;
+
+	trace_cxl_psl_ctrl(afu, CXL_PSL_SCNTL_An_Pc);
 
 	pr_devel("PSL purge request\n");
 
@@ -107,7 +116,8 @@ int cxl_psl_purge(struct cxl_afu *afu)
 			== CXL_PSL_SCNTL_An_Ps_Pending) {
 		if (time_after_eq(jiffies, timeout)) {
 			dev_warn(&afu->dev, "WARNING: PSL Purge timed out!\n");
-			return -EBUSY;
+			rc = -EBUSY;
+			goto out;
 		}
 		dsisr = cxl_p2n_read(afu, CXL_PSL_DSISR_An);
 		pr_devel_ratelimited("PSL purging... PSL_CNTL: 0x%.16llx  PSL_DSISR: 0x%.16llx\n", PSL_CNTL, dsisr);
@@ -128,7 +138,9 @@ int cxl_psl_purge(struct cxl_afu *afu)
 
 	cxl_p1n_write(afu, CXL_PSL_SCNTL_An,
 		       PSL_CNTL & ~CXL_PSL_SCNTL_An_Pc);
-	return 0;
+out:
+	trace_cxl_psl_ctrl_done(afu, CXL_PSL_SCNTL_An_Pc, rc);
+	return rc;
 }
 
 static int spa_max_procs(int spa_size)
@@ -279,6 +291,9 @@ static int do_process_element_cmd(struct cxl_context *ctx,
 {
 	u64 state;
 	unsigned long timeout = jiffies + (HZ * CXL_TIMEOUT);
+	int rc = 0;
+
+	trace_cxl_llcmd(ctx, cmd);
 
 	WARN_ON(!ctx->afu->enabled);
 
@@ -290,12 +305,14 @@ static int do_process_element_cmd(struct cxl_context *ctx,
 	while (1) {
 		if (time_after_eq(jiffies, timeout)) {
 			dev_warn(&ctx->afu->dev, "WARNING: Process Element Command timed out!\n");
-			return -EBUSY;
+			rc = -EBUSY;
+			goto out;
 		}
 		state = be64_to_cpup(ctx->afu->sw_command_status);
 		if (state == ~0ULL) {
 			pr_err("cxl: Error adding process element to AFU\n");
-			return -1;
+			rc = -1;
+			goto out;
 		}
 		if ((state & (CXL_SPA_SW_CMD_MASK | CXL_SPA_SW_STATE_MASK  | CXL_SPA_SW_LINK_MASK)) ==
 		    (cmd | (cmd >> 16) | ctx->pe))
@@ -310,7 +327,9 @@ static int do_process_element_cmd(struct cxl_context *ctx,
 		schedule();
 
 	}
-	return 0;
+out:
+	trace_cxl_llcmd_done(ctx, cmd, rc);
+	return rc;
 }
 
 static int add_process_element(struct cxl_context *ctx)
@@ -630,6 +649,8 @@ static inline int detach_process_native_afu_directed(struct cxl_context *ctx)
 
 int cxl_detach_process(struct cxl_context *ctx)
 {
+	trace_cxl_detach(ctx);
+
 	if (ctx->afu->current_mode == CXL_MODE_DEDICATED)
 		return detach_process_native_dedicated(ctx);
 
@@ -668,6 +689,7 @@ static void recover_psl_err(struct cxl_afu *afu, u64 errstat)
 
 int cxl_ack_irq(struct cxl_context *ctx, u64 tfc, u64 psl_reset_mask)
 {
+	trace_cxl_psl_irq_ack(ctx, tfc);
 	if (tfc)
 		cxl_p2n_write(ctx->afu, CXL_PSL_TFC_An, tfc);
 	if (psl_reset_mask)