[PATCH v6 5/9] tpm, tpm_tis: Only handle supported interrupts

Lino Sanfilippo
2022-06-21T13:35:04Z

According to the TPM Interface Specification (TIS) support for "stsValid"
and "commandReady" interrupts is only optional.
This has to be taken into account when handling the interrupts in functions
like wait_for_tpm_stat(). To determine the supported interrupts use the
capability query.

Also adjust wait_for_tpm_stat() to only wait for interrupt reported status
changes. After that process all the remaining status changes by polling
the status register.

Signed-off-by: Lino Sanfilippo <l.sanfilippo@kunbus.com>
---
drivers/char/tpm/tpm_tis_core.c | 119 +++++++++++++++++++-------------
drivers/char/tpm/tpm_tis_core.h | 1 +
2 files changed, 72 insertions(+), 48 deletions(-)

diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c
index 09d8f04cbc81..cb469591373a 100644
--- a/drivers/char/tpm/tpm_tis_core.c
+++ b/drivers/char/tpm/tpm_tis_core.c
@@ -53,41 +53,63 @@ static int wait_for_tpm_stat(struct tpm_chip *chip, u8 mask,
long rc;
u8 status;
bool canceled = false;
+ u8 sts_mask = 0;
+ int ret = 0;

/* check current status */
status = chip->ops->status(chip);
if ((status & mask) == mask)
return 0;

- stop = jiffies + timeout;
+ /* check what status changes can be handled by irqs */
+ if (priv->int_mask & TPM_INTF_STS_VALID_INT)
+ sts_mask |= TPM_STS_VALID;

- if (chip->flags & TPM_CHIP_FLAG_IRQ) {
+ if (priv->int_mask & TPM_INTF_DATA_AVAIL_INT)
+ sts_mask |= TPM_STS_DATA_AVAIL;
+
+ if (priv->int_mask & TPM_INTF_CMD_READY_INT)
+ sts_mask |= TPM_STS_COMMAND_READY;
+
+ sts_mask &= mask;
+
+ stop = jiffies + timeout;
+ /* process status changes with irq support */
+ if (sts_mask) {
+ ret = -ETIME;
again:
timeout = stop - jiffies;
if ((long)timeout <= 0)
return -ETIME;
rc = wait_event_interruptible_timeout(*queue,
- wait_for_tpm_stat_cond(chip, mask, check_cancel,
+ wait_for_tpm_stat_cond(chip, sts_mask, check_cancel,
&canceled),
timeout);
if (rc > 0) {
if (canceled)
return -ECANCELED;
- return 0;
+ ret = 0;
}
if (rc == -ERESTARTSYS && freezing(current)) {
clear_thread_flag(TIF_SIGPENDING);
goto again;
}
- } else {
- do {
- usleep_range(priv->timeout_min,
- priv->timeout_max);
- status = chip->ops->status(chip);
- if ((status & mask) == mask)
- return 0;
- } while (time_before(jiffies, stop));
}
+
+ if (ret)
+ return ret;
+
+ mask &= ~sts_mask;
+ if (!mask) /* all done */
+ return 0;
+ /* process status changes without irq support */
+ do {
+ status = chip->ops->status(chip);
+ if ((status & mask) == mask)
+ return 0;
+ usleep_range(priv->timeout_min,
+ priv->timeout_max);
+ } while (time_before(jiffies, stop));
return -ETIME;
}

@@ -1007,8 +1029,39 @@ int tpm_tis_core_init(struct device *dev, struct tpm_tis_data *priv, int irq,
if (rc < 0)
goto out_err;

- intmask |= TPM_INTF_CMD_READY_INT | TPM_INTF_LOCALITY_CHANGE_INT |
- TPM_INTF_DATA_AVAIL_INT | TPM_INTF_STS_VALID_INT;
+ /* Figure out the capabilities */
+ rc = tpm_tis_read32(priv, TPM_INTF_CAPS(priv->locality), &intfcaps);
+ if (rc < 0)
+ goto out_err;
+
+ dev_dbg(dev, "TPM interface capabilities (0x%x):\n",
+ intfcaps);
+ if (intfcaps & TPM_INTF_BURST_COUNT_STATIC)
+ dev_dbg(dev, "\tBurst Count Static\n");
+ if (intfcaps & TPM_INTF_CMD_READY_INT) {
+ intmask |= TPM_INTF_CMD_READY_INT;
+ dev_dbg(dev, "\tCommand Ready Int Support\n");
+ }
+ if (intfcaps & TPM_INTF_INT_EDGE_FALLING)
+ dev_dbg(dev, "\tInterrupt Edge Falling\n");
+ if (intfcaps & TPM_INTF_INT_EDGE_RISING)
+ dev_dbg(dev, "\tInterrupt Edge Rising\n");
+ if (intfcaps & TPM_INTF_INT_LEVEL_LOW)
+ dev_dbg(dev, "\tInterrupt Level Low\n");
+ if (intfcaps & TPM_INTF_INT_LEVEL_HIGH)
+ dev_dbg(dev, "\tInterrupt Level High\n");
+ if (intfcaps & TPM_INTF_LOCALITY_CHANGE_INT)
+ intmask |= TPM_INTF_LOCALITY_CHANGE_INT;
+ dev_dbg(dev, "\tLocality Change Int Support\n");
+ if (intfcaps & TPM_INTF_STS_VALID_INT) {
+ intmask |= TPM_INTF_STS_VALID_INT;
+ dev_dbg(dev, "\tSts Valid Int Support\n");
+ }
+ if (intfcaps & TPM_INTF_DATA_AVAIL_INT) {
+ intmask |= TPM_INTF_DATA_AVAIL_INT;
+ dev_dbg(dev, "\tData Avail Int Support\n");
+ }
+
intmask &= ~TPM_GLOBAL_INT_ENABLE;

rc = request_locality(chip, 0);
@@ -1042,32 +1095,6 @@ int tpm_tis_core_init(struct device *dev, struct tpm_tis_data *priv, int irq,
goto out_err;
}

- /* Figure out the capabilities */
- rc = tpm_tis_read32(priv, TPM_INTF_CAPS(priv->locality), &intfcaps);
- if (rc < 0)
- goto out_err;
-
- dev_dbg(dev, "TPM interface capabilities (0x%x):\n",
- intfcaps);
- if (intfcaps & TPM_INTF_BURST_COUNT_STATIC)
- dev_dbg(dev, "\tBurst Count Static\n");
- if (intfcaps & TPM_INTF_CMD_READY_INT)
- dev_dbg(dev, "\tCommand Ready Int Support\n");
- if (intfcaps & TPM_INTF_INT_EDGE_FALLING)
- dev_dbg(dev, "\tInterrupt Edge Falling\n");
- if (intfcaps & TPM_INTF_INT_EDGE_RISING)
- dev_dbg(dev, "\tInterrupt Edge Rising\n");
- if (intfcaps & TPM_INTF_INT_LEVEL_LOW)
- dev_dbg(dev, "\tInterrupt Level Low\n");
- if (intfcaps & TPM_INTF_INT_LEVEL_HIGH)
- dev_dbg(dev, "\tInterrupt Level High\n");
- if (intfcaps & TPM_INTF_LOCALITY_CHANGE_INT)
- dev_dbg(dev, "\tLocality Change Int Support\n");
- if (intfcaps & TPM_INTF_STS_VALID_INT)
- dev_dbg(dev, "\tSts Valid Int Support\n");
- if (intfcaps & TPM_INTF_DATA_AVAIL_INT)
- dev_dbg(dev, "\tData Avail Int Support\n");
-
/* INTERRUPT Setup */
init_waitqueue_head(&priv->read_queue);
init_waitqueue_head(&priv->int_queue);
@@ -1098,7 +1125,9 @@ int tpm_tis_core_init(struct device *dev, struct tpm_tis_data *priv, int irq,
else
tpm_tis_probe_irq(chip, intmask);

- if (!(chip->flags & TPM_CHIP_FLAG_IRQ)) {
+ if (chip->flags & TPM_CHIP_FLAG_IRQ) {
+ priv->int_mask = intmask;
+ } else {
dev_err(&chip->dev, FW_BUG
"TPM interrupt not working, polling instead\n");

@@ -1145,13 +1174,7 @@ static void tpm_tis_reenable_interrupts(struct tpm_chip *chip)
if (rc < 0)
goto out;

- rc = tpm_tis_read32(priv, TPM_INT_ENABLE(priv->locality), &intmask);
- if (rc < 0)
- goto out;
-
- intmask |= TPM_INTF_CMD_READY_INT
- | TPM_INTF_LOCALITY_CHANGE_INT | TPM_INTF_DATA_AVAIL_INT
- | TPM_INTF_STS_VALID_INT | TPM_GLOBAL_INT_ENABLE;
+ intmask = priv->int_mask | TPM_GLOBAL_INT_ENABLE;

tpm_tis_write32(priv, TPM_INT_ENABLE(priv->locality), intmask);

diff --git a/drivers/char/tpm/tpm_tis_core.h b/drivers/char/tpm/tpm_tis_core.h
index bf07379dea42..e005eb99480e 100644
--- a/drivers/char/tpm/tpm_tis_core.h
+++ b/drivers/char/tpm/tpm_tis_core.h
@@ -93,6 +93,7 @@ struct tpm_tis_data {
u16 manufacturer_id;
int locality;
int irq;
+ unsigned int int_mask;
unsigned long flags;
void __iomem *ilb_base_addr;
u16 clkrun_enabled;
--
2.36.1