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* [PATCH v2 1/2] misc: Add clock control logic into Aspeed LPC SNOOP driver
@ 2020-12-08  9:17 ` John Wang
  0 siblings, 0 replies; 19+ messages in thread
From: John Wang @ 2020-12-08  9:17 UTC (permalink / raw)
  To: xuxiaohan, yulei.sh
  Cc: Jae Hyun Yoo, Vernon Mauery, Joel Stanley, Andrew Jeffery,
	Patrick Venture, Robert Lippert, Greg Kroah-Hartman,
	Benjamin Fair, moderated list:ARM/ASPEED MACHINE SUPPORT,
	moderated list:ARM/ASPEED MACHINE SUPPORT, open list

From: Jae Hyun Yoo <jae.hyun.yoo@intel.com>

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 <jae.hyun.yoo@intel.com>
Signed-off-by: Vernon Mauery <vernon.mauery@linux.intel.com>
Signed-off-by: John Wang <wangzhiqiang.bj@bytedance.com>
---
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


^ permalink raw reply related	[flat|nested] 19+ messages in thread
end of thread, other threads:[~2021-02-10 10:32 UTC | newest]

Thread overview: 19+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-12-08  9:17 [PATCH v2 1/2] misc: Add clock control logic into Aspeed LPC SNOOP driver John Wang
2020-12-08  9:17 ` John Wang
2020-12-08  9:17 ` [PATCH v2 2/2] ARM: dts: aspeed: Add LCLK to lpc-snoop John Wang
2020-12-08  9:17   ` John Wang
2020-12-09  2:17 ` [PATCH v2 1/2] misc: Add clock control logic into Aspeed LPC SNOOP driver Joel Stanley
2020-12-09  2:17   ` Joel Stanley
2020-12-09  2:17   ` Joel Stanley
2020-12-09  6:41   ` Arnd Bergmann
2020-12-09  6:41     ` Arnd Bergmann
2021-01-06  9:54 ` Ryan Chen
2021-01-06  9:54   ` Ryan Chen
2021-01-15 17:04   ` Arnd Bergmann
2021-01-15 17:04     ` Arnd Bergmann
2021-01-16  1:03     ` Ryan Chen
2021-01-16  1:03       ` Ryan Chen
2021-02-09 23:27       ` Arnd Bergmann
2021-02-09 23:27         ` Arnd Bergmann
2021-02-10 10:18         ` Joel Stanley
2021-02-10 10:18           ` Joel Stanley

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