On Mon, 1 Nov 2021 at 23:18, <jae.hyun.yoo@xxxxxxxxx> wrote:
>
> From: Jae Hyun Yoo <jae.hyun.yoo@xxxxxxxxxxxxxxx>
>
> If LPC KCS driver is registered ahead of lpc-ctrl module, LPC
> KCS 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 interrupts 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 drivers should enable LCLK
> individually so this patch adds clock control logic into the LPC
> KCS driver.
>
> Fixes: be2ed207e374 ("ipmi: add an Aspeed KCS IPMI BMC driver")
> Signed-off-by: Jae Hyun Yoo <jae.hyun.yoo@xxxxxxxxxxxxxxx>
Reviewed-by: Joel Stanley <joel@xxxxxxxxx>
> ---
> drivers/char/ipmi/kcs_bmc_aspeed.c | 31 ++++++++++++++++++++++++++----
> 1 file changed, 27 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/char/ipmi/kcs_bmc_aspeed.c b/drivers/char/ipmi/kcs_bmc_aspeed.c
> index 92a37b33494c..00706472cc4d 100644
> --- a/drivers/char/ipmi/kcs_bmc_aspeed.c
> +++ b/drivers/char/ipmi/kcs_bmc_aspeed.c
> @@ -6,6 +6,7 @@
> #define pr_fmt(fmt) "aspeed-kcs-bmc: " fmt
>
> #include <linux/atomic.h>
> +#include <linux/clk.h>
> #include <linux/errno.h>
> #include <linux/interrupt.h>
> #include <linux/io.h>
> @@ -126,6 +127,8 @@ struct aspeed_kcs_bmc {
> bool remove;
> struct timer_list timer;
> } obe;
> +
> + struct clk *clk;
> };
>
> struct aspeed_kcs_of_ops {
> @@ -620,24 +623,37 @@ static int aspeed_kcs_probe(struct platform_device *pdev)
> return -ENODEV;
> }
>
> + priv->clk = devm_clk_get(&pdev->dev, NULL);
> + if (IS_ERR(priv->clk)) {
> + rc = PTR_ERR(priv->clk);
> + if (rc != -EPROBE_DEFER)
> + dev_err(&pdev->dev, "Couldn't get clock\n");
> + return rc;
> + }
> + rc = clk_prepare_enable(priv->clk);
> + if (rc) {
> + dev_err(&pdev->dev, "Couldn't enable clock\n");
> + return rc;
> + }
> +
> spin_lock_init(&priv->obe.lock);
> priv->obe.remove = false;
> timer_setup(&priv->obe.timer, aspeed_kcs_check_obe, 0);
>
> rc = aspeed_kcs_set_address(kcs_bmc, addrs, nr_addrs);
> if (rc)
> - return rc;
> + goto err;
>
> /* Host to BMC IRQ */
> rc = aspeed_kcs_config_downstream_irq(kcs_bmc, pdev);
> if (rc)
> - return rc;
> + goto err;
>
> /* BMC to Host IRQ */
> if (have_upstream_irq) {
> rc = aspeed_kcs_config_upstream_irq(priv, upstream_irq[0], upstream_irq[1]);
> if (rc < 0)
> - return rc;
> + goto err;
> } else {
> priv->upstream_irq.mode = aspeed_kcs_irq_none;
> }
> @@ -650,13 +666,19 @@ static int aspeed_kcs_probe(struct platform_device *pdev)
> rc = kcs_bmc_add_device(&priv->kcs_bmc);
> if (rc) {
> dev_warn(&pdev->dev, "Failed to register channel %d: %d\n", kcs_bmc->channel, rc);
> - return rc;
> + goto err;
> }
>
> dev_info(&pdev->dev, "Initialised channel %d at 0x%x\n",
> kcs_bmc->channel, addrs[0]);
>
> return 0;
> +
> +err:
> + aspeed_kcs_enable_channel(kcs_bmc, false);
> + clk_disable_unprepare(priv->clk);
> +
> + return rc;
> }
>
> static int aspeed_kcs_remove(struct platform_device *pdev)
> @@ -664,6 +686,7 @@ static int aspeed_kcs_remove(struct platform_device *pdev)
> struct aspeed_kcs_bmc *priv = platform_get_drvdata(pdev);
> struct kcs_bmc_device *kcs_bmc = &priv->kcs_bmc;
>
> + clk_disable_unprepare(priv->clk);
> kcs_bmc_remove_device(kcs_bmc);
>
> aspeed_kcs_enable_channel(kcs_bmc, false);
> --
> 2.25.1
>
