-----Original Message----- From: Joel Stanley joel@jms.id.au Sent: Monday, March 1, 2021 2:44 PM To: Greg Kroah-Hartman gregkh@linuxfoundation.org; John Wang wangzhiqiang.bj@bytedance.com; Yoo, Jae Hyun jae.hyun.yoo@intel.com Cc: Linux Kernel Mailing List linux-kernel@vger.kernel.org; stable@vger.kernel.org; Vernon Mauery vernon.mauery@linux.intel.com; Sasha Levin sashal@kernel.org Subject: Re: [PATCH 4.19 055/247] soc: aspeed: snoop: Add clock control logic
On Mon, 1 Mar 2021 at 16:37, Greg Kroah-Hartman gregkh@linuxfoundation.org wrote:
From: Jae Hyun Yoo jae.hyun.yoo@intel.com
[ Upstream commit 3f94cf15583be554df7aaa651b8ff8e1b68fbe51 ]
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.
Jae, John; with this backported do we need to also provide a corresponding device tree change for the stable tree, otherwise this driver will no longer probe?
Right. The second patch https://lore.kernel.org/linux-arm-kernel/20201208091748.1920-2-wangzhiqiang.... John submitted should be applied to stable tree too to make this module be probed correctly.
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 Reviewed-by: Joel Stanley joel@jms.id.au Link: https://lore.kernel.org/r/20201208091748.1920-1-wangzhiqiang.bj@byteda nce.com Signed-off-by: Joel Stanley joel@jms.id.au Signed-off-by: Sasha Levin sashal@kernel.org
drivers/misc/aspeed-lpc-snoop.c | 30 +++++++++++++++++++++++++++-
--
1 file changed, 27 insertions(+), 3 deletions(-)
diff --git a/drivers/misc/aspeed-lpc-snoop.c b/drivers/misc/aspeed-lpc-snoop.c index c10be21a1663d..b4a776bf44bc5 100644 --- a/drivers/misc/aspeed-lpc-snoop.c +++ b/drivers/misc/aspeed-lpc-snoop.c @@ -15,6 +15,7 @@ */
#include <linux/bitops.h> +#include <linux/clk.h> #include <linux/interrupt.h> #include <linux/fs.h> #include <linux/kfifo.h> @@ -71,6 +72,7 @@ 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]; };@@ -286,22 +288,42 @@ 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;}
@@ -313,6 +335,8 @@ 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;}
-- 2.27.0