On Mon, 1 Mar 2021 at 16:37, Greg Kroah-Hartman
<gregkh@xxxxxxxxxxxxxxxxxxx> wrote:
>
> From: Jae Hyun Yoo <jae.hyun.yoo@xxxxxxxxx>
>
> [ 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?
>
> Fixes: 3772e5da4454 ("drivers/misc: Aspeed LPC snoop output using misc chardev")
> Signed-off-by: Jae Hyun Yoo <jae.hyun.yoo@xxxxxxxxx>
> Signed-off-by: Vernon Mauery <vernon.mauery@xxxxxxxxxxxxxxx>
> Signed-off-by: John Wang <wangzhiqiang.bj@xxxxxxxxxxxxx>
> Reviewed-by: Joel Stanley <joel@xxxxxxxxx>
> Link: https://lore.kernel.org/r/20201208091748.1920-1-wangzhiqiang.bj@xxxxxxxxxxxxx
> Signed-off-by: Joel Stanley <joel@xxxxxxxxx>
> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
> ---
> 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
>
>
>
