crypto: ccree - fix PM race condition

The PM code was racy, possibly causing the driver to submit
requests to a powered down device. Fix the race and while
at it simplify the PM code.

Signed-off-by: Gilad Ben-Yossef <gilad@benyossef.com>
Fixes: 1358c13a48c4 ("crypto: ccree - fix resume race condition on init")
Cc: stable@kernel.org # v4.20
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 6 insertions, 22 deletions

diff --git a/drivers/crypto/ccree/cc_pm.c b/drivers/crypto/ccree/cc_pm.c
index 79c612144310..ee9e9cba2fbb 100644
--- a/drivers/crypto/ccree/cc_pm.c
+++ b/drivers/crypto/ccree/cc_pm.c
@@ -22,14 +22,8 @@ const struct dev_pm_ops ccree_pm = {
 int cc_pm_suspend(struct device *dev)
 {
 	struct cc_drvdata *drvdata = dev_get_drvdata(dev);
-	int rc;
 
 	dev_dbg(dev, "set HOST_POWER_DOWN_EN\n");
-	rc = cc_suspend_req_queue(drvdata);
-	if (rc) {
-		dev_err(dev, "cc_suspend_req_queue (%x)\n", rc);
-		return rc;
-	}
 	fini_cc_regs(drvdata);
 	cc_iowrite(drvdata, CC_REG(HOST_POWER_DOWN_EN), POWER_DOWN_ENABLE);
 	cc_clk_off(drvdata);
@@ -63,13 +57,6 @@ int cc_pm_resume(struct device *dev)
 	/* check if tee fips error occurred during power down */
 	cc_tee_handle_fips_error(drvdata);
 
-	rc = cc_resume_req_queue(drvdata);
-	if (rc) {
-		dev_err(dev, "cc_resume_req_queue (%x)\n", rc);
-		return rc;
-	}
-
-	/* must be after the queue resuming as it uses the HW queue*/
 	cc_init_hash_sram(drvdata);
 
 	return 0;
@@ -80,10 +67,8 @@ int cc_pm_get(struct device *dev)
 	int rc = 0;
 	struct cc_drvdata *drvdata = dev_get_drvdata(dev);
 
-	if (cc_req_queue_suspended(drvdata))
+	if (drvdata->pm_on)
 		rc = pm_runtime_get_sync(dev);
-	else
-		pm_runtime_get_noresume(dev);
 
 	return (rc == 1 ? 0 : rc);
 }
@@ -93,14 +78,11 @@ int cc_pm_put_suspend(struct device *dev)
 	int rc = 0;
 	struct cc_drvdata *drvdata = dev_get_drvdata(dev);
 
-	if (!cc_req_queue_suspended(drvdata)) {
+	if (drvdata->pm_on) {
 		pm_runtime_mark_last_busy(dev);
 		rc = pm_runtime_put_autosuspend(dev);
-	} else {
-		/* Something wrong happens*/
-		dev_err(dev, "request to suspend already suspended queue");
-		rc = -EBUSY;
 	}
+
 	return rc;
 }
 
@@ -117,7 +99,7 @@ int cc_pm_init(struct cc_drvdata *drvdata)
 	/* must be before the enabling to avoid redundant suspending */
 	pm_runtime_set_autosuspend_delay(dev, CC_SUSPEND_TIMEOUT);
 	pm_runtime_use_autosuspend(dev);
-	/* activate the PM module */
+	/* set us as active - note we won't do PM ops until cc_pm_go()! */
 	return pm_runtime_set_active(dev);
 }
 
@@ -125,9 +107,11 @@ int cc_pm_init(struct cc_drvdata *drvdata)
 void cc_pm_go(struct cc_drvdata *drvdata)
 {
 	pm_runtime_enable(drvdata_to_dev(drvdata));
+	drvdata->pm_on = true;
 }
 
 void cc_pm_fini(struct cc_drvdata *drvdata)
 {
 	pm_runtime_disable(drvdata_to_dev(drvdata));
+	drvdata->pm_on = false;
 }