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Subject[RFC PATCH v5] tpm_tis: verify interrupt during init
On Sat, 30 Aug 2014, Jason Gunthorpe wrote:

> On Fri, Aug 29, 2014 at 11:59:32PM +0000, Scot Doyle wrote:
>
>> I tried calling tpm_get_timeouts only during the interrupt test, but again
>> was timed out after 30 seconds. The interrupt wait in tis_send calls
>> tpm_calc_ordinal_duration, which uses a default timeout of two minutes
>> when chip->vendor.duration[duration_idx] hasn't been set. Thus the second
>> call to tpm_get_timeouts in tpm_tis_init.
>
> So the strategy is to read the timeouts and hope that the chip reports
> something small and reasonable, then do a second read?
>
> Seems reasonable, but with this new arrangement we could also use an
> alternate polling logic for 'testing_int' that did the normal polling
> loop unconditionally and then checked if the interrupt was
> delivered. This would give a minimal dealy.

I like the idea. And then tpm_do_selftest could be used for the interrupt
verification instead of a second tpm_get_timeouts?

The output is now
[ 1.526798] tpm_tis 00:08: 1.2 TPM (device-id 0xB, rev-id 16)
[ 5.914732] tpm_tis 00:08: [Firmware Bug]: TPM interrupt not working, polling instead

Enjoy the weekend!

---
diff --git a/drivers/char/tpm/tpm_tis.c b/drivers/char/tpm/tpm_tis.c
index 2c46734..7a5f5b2 100644
--- a/drivers/char/tpm/tpm_tis.c
+++ b/drivers/char/tpm/tpm_tis.c
@@ -75,6 +75,11 @@ enum tis_defaults {
#define TPM_DID_VID(l) (0x0F00 | ((l) << 12))
#define TPM_RID(l) (0x0F04 | ((l) << 12))

+struct priv_data {
+ int test_irq;
+ int int_count;
+};
+
static LIST_HEAD(tis_chips);
static DEFINE_MUTEX(tis_lock);

@@ -338,6 +343,21 @@ out_err:
return rc;
}

+static void disable_interrupts(struct tpm_chip *chip)
+{
+ u32 intmask;
+ intmask =
+ ioread32(chip->vendor.iobase +
+ TPM_INT_ENABLE(chip->vendor.locality));
+ intmask |= TPM_INTF_CMD_READY_INT | TPM_INTF_LOCALITY_CHANGE_INT |
+ TPM_INTF_DATA_AVAIL_INT | TPM_INTF_STS_VALID_INT;
+ iowrite32(intmask,
+ chip->vendor.iobase +
+ TPM_INT_ENABLE(chip->vendor.locality));
+ free_irq(chip->vendor.irq, chip);
+ chip->vendor.irq = 0;
+}
+
/*
* If interrupts are used (signaled by an irq set in the vendor structure)
* tpm.c can skip polling for the data to be available as the interrupt is
@@ -347,6 +367,7 @@ static int tpm_tis_send(struct tpm_chip *chip, u8 *buf, size_t len)
{
int rc;
u32 ordinal;
+ struct priv_data *priv = chip->vendor.priv;

rc = tpm_tis_send_data(chip, buf, len);
if (rc < 0)
@@ -358,13 +379,27 @@ static int tpm_tis_send(struct tpm_chip *chip, u8 *buf, size_t len)

if (chip->vendor.irq) {
ordinal = be32_to_cpu(*((__be32 *) (buf + 6)));
- if (wait_for_tpm_stat
- (chip, TPM_STS_DATA_AVAIL | TPM_STS_VALID,
- tpm_calc_ordinal_duration(chip, ordinal),
- &chip->vendor.read_queue, false) < 0) {
+ if (priv->test_irq)
+ chip->vendor.irq = 0;
+ rc = wait_for_tpm_stat
+ (chip, TPM_STS_DATA_AVAIL | TPM_STS_VALID,
+ tpm_calc_ordinal_duration(chip, ordinal),
+ &chip->vendor.read_queue, false);
+ if (priv->test_irq)
+ chip->vendor.irq = priv->test_irq;
+ if (rc < 0) {
rc = -ETIME;
goto out_err;
}
+ if (priv->test_irq) {
+ priv->test_irq = 0;
+ msleep(1);
+ if (!priv->int_count) {
+ disable_interrupts(chip);
+ dev_err(chip->dev,
+ FW_BUG "TPM interrupt not working, polling instead\n");
+ }
+ }
}
return len;
out_err:
@@ -505,6 +540,7 @@ static irqreturn_t tis_int_handler(int dummy, void *dev_id)
if (interrupt == 0)
return IRQ_NONE;

+ ((struct priv_data*)chip->vendor.priv)->int_count++;
if (interrupt & TPM_INTF_DATA_AVAIL_INT)
wake_up_interruptible(&chip->vendor.read_queue);
if (interrupt & TPM_INTF_LOCALITY_CHANGE_INT)
@@ -534,10 +570,14 @@ static int tpm_tis_init(struct device *dev, resource_size_t start,
u32 vendor, intfcaps, intmask;
int rc, i, irq_s, irq_e, probe;
struct tpm_chip *chip;
+ struct priv_data *priv;

if (!(chip = tpm_register_hardware(dev, &tpm_tis)))
return -ENODEV;

+ priv = devm_kzalloc(dev, sizeof(struct priv_data), GFP_KERNEL);
+ chip->vendor.priv = priv;
+
chip->vendor.iobase = ioremap(start, len);
if (!chip->vendor.iobase) {
rc = -EIO;
@@ -612,12 +652,6 @@ static int tpm_tis_init(struct device *dev, resource_size_t start,
goto out_err;
}

- if (tpm_do_selftest(chip)) {
- dev_err(dev, "TPM self test failed\n");
- rc = -ENODEV;
- goto out_err;
- }
-
/* INTERRUPT Setup */
init_waitqueue_head(&chip->vendor.read_queue);
init_waitqueue_head(&chip->vendor.int_queue);
@@ -719,6 +753,14 @@ static int tpm_tis_init(struct device *dev, resource_size_t start,
}
}

+ /* Test interrupt and prepare for later save state */
+ priv->test_irq = chip->vendor.irq;
+ if (tpm_do_selftest(chip)) {
+ dev_err(dev, "TPM self test failed\n");
+ rc = -ENODEV;
+ goto out_err;
+ }
+
INIT_LIST_HEAD(&chip->vendor.list);
mutex_lock(&tis_lock);
list_add(&chip->vendor.list, &tis_chips);


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