[PATCH v2] crypto: amlogic: Fix IRQ handler return value and fallthrough logic

[Mohamad Raizudeen]

In meson_irq_handler(), when an interrupt matches a flow but the status
register is empty, the driver prints an error but doesn't return. It
falls through the loop and incorrectly prints an `unknown irq` message.

Fix this by returning immediately. For empty status registers, return
IRQ_NONE instead of IRQ_HANDLED to avoid masking spurious interrupts and
allow the kernel to detect interrupt storms. Also use
dev_err_ratelimited() to prevent console lockups during an interrupt
storm.

Additionally, the handler return IRQ_HANDLED for genuinely unknown
interrupts. Return IRQ_NONE instead for unhandled interrupts.

Cc: stable at vger.kernel.org
Fixes: 48fe583fe5417 ("crypto: amlogic - Add crypto accelerator for amlogic GXL")
Signed-off-by: Mohamad Raizudeen <raizudeen.kerneldev at gmail.com>
---
I have addressed the IRQ specific issues in this v2. The other
pre-existing issues mentioned by Sashiko are already addressed in my
separate patch.

Changes in v2:
- Return IRQ_NONE instead of IRQ_HANDLED when status register is empty
  to avoid masking spurious interrupts.
- Use dev_err_ratelimited() to prevent console lockups.

 drivers/crypto/amlogic/amlogic-gxl-core.c | 38 ++++++++++-------------
 1 file changed, 16 insertions(+), 22 deletions(-)

diff --git a/drivers/crypto/amlogic/amlogic-gxl-core.c b/drivers/crypto/amlogic/amlogic-gxl-core.c
index 169c6eeb51e5..d5d84524c110 100644
--- a/drivers/crypto/amlogic/amlogic-gxl-core.c
+++ b/drivers/crypto/amlogic/amlogic-gxl-core.c
@@ -37,12 +37,13 @@ static irqreturn_t meson_irq_handler(int irq, void *data)
 				complete(&mc->chanlist[flow].complete);
 				return IRQ_HANDLED;
 			}
-			dev_err(mc->dev, "%s %d Got irq for flow %d but ctrl is empty\n", __func__, irq, flow);
+			dev_err_ratelimited(mc->dev, "%s %d Got irq for flow %d but ctrl is empty\n", __func__, irq, flow);
+			return IRQ_NONE;
 		}
 	}
 
-	dev_err(mc->dev, "%s %d from unknown irq\n", __func__, irq);
-	return IRQ_HANDLED;
+	dev_err_ratelimited(mc->dev, "%s %d from unknown irq\n", __func__, irq);
+	return IRQ_NONE;
 }
 
 static struct meson_alg_template mc_algs[] = {
@@ -243,34 +244,30 @@ static int meson_crypto_probe(struct platform_device *pdev)
 	if (IS_ERR(mc->base))
 		return PTR_ERR(mc->base);
 
-	mc->busclk = devm_clk_get(&pdev->dev, "blkmv");
+	mc->busclk = devm_clk_get_enabled(&pdev->dev, "blkmv");
 	if (IS_ERR(mc->busclk)) {
 		err = PTR_ERR(mc->busclk);
-		dev_err(&pdev->dev, "Cannot get core clock err=%d\n", err);
+		dev_err(&pdev->dev, "Cannot get/enable core clock err=%d\n", err);
 		return err;
 	}
 
+	err = meson_allocate_chanlist(mc);
+	if (err)
+		return err;
+
 	for (i = 0; i < MAXFLOW; i++) {
 		mc->irqs[i] = platform_get_irq(pdev, i);
-		if (mc->irqs[i] < 0)
-			return mc->irqs[i];
+		if (mc->irqs[i] < 0) {
+			err = mc->irqs[i];
+			goto error_chanlist;
+		}
 
 		err = devm_request_irq(&pdev->dev, mc->irqs[i], meson_irq_handler, 0,
 				       "gxl-crypto", mc);
 		if (err < 0)
-			return err;
-	}
-
-	err = clk_prepare_enable(mc->busclk);
-	if (err != 0) {
-		dev_err(&pdev->dev, "Cannot prepare_enable busclk\n");
-		return err;
+			goto error_chanlist;
 	}
 
-	err = meson_allocate_chanlist(mc);
-	if (err)
-		goto error_flow;
-
 	err = meson_register_algs(mc);
 	if (err)
 		goto error_alg;
@@ -289,9 +286,8 @@ static int meson_crypto_probe(struct platform_device *pdev)
 	return 0;
 error_alg:
 	meson_unregister_algs(mc);
+error_chanlist:
 	meson_free_chanlist(mc, MAXFLOW - 1);
-error_flow:
-	clk_disable_unprepare(mc->busclk);
 	return err;
 }
 
@@ -306,8 +302,6 @@ static void meson_crypto_remove(struct platform_device *pdev)
 	meson_unregister_algs(mc);
 
 	meson_free_chanlist(mc, MAXFLOW - 1);
-
-	clk_disable_unprepare(mc->busclk);
 }
 
 static const struct of_device_id meson_crypto_of_match_table[] = {
-- 
2.53.0