-----Original Message-----
From: Linux-aspeed
[off-list ref] On
Behalf Of John Wang
Sent: Tuesday, December 8, 2020 5:18 PM
To: xuxiaohan at bytedance.com; yulei.sh at bytedance.com
Cc: Robert Lippert <redacted>; moderated list:ARM/ASPEED
MACHINE SUPPORT [off-list ref]; Greg Kroah-Hartman
[off-list ref]; Vernon Mauery
[off-list ref]; open list [off-list ref];
Jae Hyun Yoo [off-list ref]; Patrick Venture
[off-list ref]; moderated list:ARM/ASPEED MACHINE SUPPORT
[off-list ref]
Subject: [PATCH v2 1/2] misc: Add clock control logic into Aspeed LPC SNOOP
driver

From: Jae Hyun Yoo <redacted>

If LPC SNOOP driver is registered ahead of lpc-ctrl module, LPC SNOOP block
will be enabled without heart beating of LCLK until lpc-ctrl enables the LCLK.
This issue causes improper handling on host interrupts when the host sends
interrupt in that time frame.
Then kernel eventually forcibly disables the interrupt with dumping stack and
printing a 'nobody cared this irq' message out.

To prevent this issue, all LPC sub-nodes should enable LCLK individually so this
patch adds clock control logic into the LPC SNOOP driver.

Fixes: 3772e5da4454 ("drivers/misc: Aspeed LPC snoop output using misc
chardev")

Signed-off-by: Jae Hyun Yoo <redacted>
Signed-off-by: Vernon Mauery <redacted>
Signed-off-by: John Wang <redacted>
---
v2:
  reword: Add fixes line
---
 drivers/soc/aspeed/aspeed-lpc-snoop.c | 30 ++++++++++++++++++++++++---
 1 file changed, 27 insertions(+), 3 deletions(-)

diff --git a/drivers/soc/aspeed/aspeed-lpc-snoop.c

b/drivers/soc/aspeed/aspeed-lpc-snoop.c
index 682ba0eb4eba..20acac6342ef 100644

--- a/drivers/soc/aspeed/aspeed-lpc-snoop.c
+++ b/drivers/soc/aspeed/aspeed-lpc-snoop.c

@@ -11,6 +11,7 @@
  */

 #include <linux/bitops.h>
+#include <linux/clk.h>
 #include <linux/interrupt.h>
 #include <linux/fs.h>
 #include <linux/kfifo.h>

@@ -67,6 +68,7 @@ struct aspeed_lpc_snoop_channel {  struct

aspeed_lpc_snoop {
 	struct regmap		*regmap;
 	int			irq;
+	struct clk		*clk;
 	struct aspeed_lpc_snoop_channel chan[NUM_SNOOP_CHANNELS];  };

@@ -282,22 +284,42 @@ static int aspeed_lpc_snoop_probe(struct

platform_device *pdev)
 		return -ENODEV;
 	}

+	lpc_snoop->clk = devm_clk_get(dev, NULL);
+	if (IS_ERR(lpc_snoop->clk)) {
+		rc = PTR_ERR(lpc_snoop->clk);
+		if (rc != -EPROBE_DEFER)
+			dev_err(dev, "couldn't get clock\n");
+		return rc;
+	}
+	rc = clk_prepare_enable(lpc_snoop->clk);
+	if (rc) {
+		dev_err(dev, "couldn't enable clock\n");
+		return rc;
+	}
+
 	rc = aspeed_lpc_snoop_config_irq(lpc_snoop, pdev);
 	if (rc)
-		return rc;
+		goto err;

 	rc = aspeed_lpc_enable_snoop(lpc_snoop, dev, 0, port);
 	if (rc)
-		return rc;
+		goto err;

 	/* Configuration of 2nd snoop channel port is optional */
 	if (of_property_read_u32_index(dev->of_node, "snoop-ports",
 				       1, &port) == 0) {
 		rc = aspeed_lpc_enable_snoop(lpc_snoop, dev, 1, port);
-		if (rc)
+		if (rc) {
 			aspeed_lpc_disable_snoop(lpc_snoop, 0);
+			goto err;
+		}
 	}

+	return 0;
+
+err:
+	clk_disable_unprepare(lpc_snoop->clk);
+
 	return rc;
 }

@@ -309,6 +331,8 @@ static int aspeed_lpc_snoop_remove(struct

platform_device *pdev)
 	aspeed_lpc_disable_snoop(lpc_snoop, 0);
 	aspeed_lpc_disable_snoop(lpc_snoop, 1);

+	clk_disable_unprepare(lpc_snoop->clk);
+
 	return 0;
 }

--
2.25.1