[PATCH v2] tpm_tis: Disable interrupts if interrupt storm detected

[Jerry Snitselaar]

When enabling the interrupt code for the tpm_tis driver we have
noticed some systems have a bios issue causing an interrupt storm to
occur. The issue isn't limited to a single tpm or system manufacturer
so keeping a denylist of systems with the issue isn't optimal. Instead
try to detect the problem occurring, disable interrupts, and revert to
polling when it happens.

Cc: Jarkko Sakkinen <jar...@kernel.org>
Cc: Jason Gunthorpe <j...@ziepe.ca>
Cc: Peter Huewe <peterhu...@gmx.de>
Cc: James Bottomley <james.bottom...@hansenpartnership.com>
Cc: Matthew Garrett <mj...@google.com>
Cc: Hans de Goede <hdego...@redhat.com>
Signed-off-by: Jerry Snitselaar <jsnit...@redhat.com>
---
v2: drop tpm_tis specific workqueue and use just system_wq

drivers/char/tpm/tpm_tis_core.c | 27 +++++++++++++++++++++++++++
 drivers/char/tpm/tpm_tis_core.h |  2 ++
 2 files changed, 29 insertions(+)

diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c
index 23b60583928b..72cc8a5a152c 100644
--- a/drivers/char/tpm/tpm_tis_core.c
+++ b/drivers/char/tpm/tpm_tis_core.c
@@ -24,6 +24,8 @@
 #include <linux/wait.h>
 #include <linux/acpi.h>
 #include <linux/freezer.h>
+#include <linux/workqueue.h>
+#include <linux/kernel_stat.h>
 #include "tpm.h"
 #include "tpm_tis_core.h"
 
@@ -745,9 +747,23 @@ static irqreturn_t tis_int_handler(int dummy, void *dev_id)
 {
        struct tpm_chip *chip = dev_id;
        struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
+       static bool check_storm = true;
+       static unsigned int check_start;
        u32 interrupt;
        int i, rc;
 
+       if (unlikely(check_storm)) {
+               if (!check_start) {
+                       check_start = jiffies_to_msecs(jiffies);
+               } else if ((kstat_irqs(priv->irq) > 1000) &&
+                          (jiffies_to_msecs(jiffies) - check_start < 500)) {
+                       check_storm = false;
+                       schedule_work(&priv->storm_work);
+               } else if (jiffies_to_msecs(jiffies) - check_start >= 500) {
+                       check_storm = false;
+               }
+       }
+
        rc = tpm_tis_read32(priv, TPM_INT_STATUS(priv->locality), &interrupt);
        if (rc < 0)
                return IRQ_NONE;
@@ -987,6 +1003,14 @@ static const struct tpm_class_ops tpm_tis = {
        .clk_enable = tpm_tis_clkrun_enable,
 };
 
+static void tpm_tis_storm_work(struct work_struct *work)
+{
+       struct tpm_tis_data *priv = container_of(work, struct tpm_tis_data, 
storm_work);
+
+       disable_interrupts(priv->chip);
+       dev_warn(&priv->chip->dev, "Interrupt storm detected, using 
polling.\n");
+}
+
 int tpm_tis_core_init(struct device *dev, struct tpm_tis_data *priv, int irq,
                      const struct tpm_tis_phy_ops *phy_ops,
                      acpi_handle acpi_dev_handle)
@@ -1003,6 +1027,9 @@ int tpm_tis_core_init(struct device *dev, struct 
tpm_tis_data *priv, int irq,
        if (IS_ERR(chip))
                return PTR_ERR(chip);
 
+       priv->chip = chip;
+       INIT_WORK(&priv->storm_work, tpm_tis_storm_work);
+
 #ifdef CONFIG_ACPI
        chip->acpi_dev_handle = acpi_dev_handle;
 #endif
diff --git a/drivers/char/tpm/tpm_tis_core.h b/drivers/char/tpm/tpm_tis_core.h
index edeb5dc61c95..5630f294dc0c 100644
--- a/drivers/char/tpm/tpm_tis_core.h
+++ b/drivers/char/tpm/tpm_tis_core.h
@@ -95,6 +95,8 @@ struct tpm_tis_data {
        u16 clkrun_enabled;
        wait_queue_head_t int_queue;
        wait_queue_head_t read_queue;
+       struct work_struct storm_work;
+       struct tpm_chip *chip;
        const struct tpm_tis_phy_ops *phy_ops;
        unsigned short rng_quality;
 };
-- 
2.27.0