diff options
author | Lino Sanfilippo <l.sanfilippo@kunbus.com> | 2022-11-24 16:55:33 +0300 |
---|---|---|
committer | Jarkko Sakkinen <jarkko@kernel.org> | 2023-04-24 16:15:53 +0300 |
commit | 7a2f55d0be296c4e81fd782f3d6c43ed4ec7e265 (patch) | |
tree | 948aff0c3ce7d61f398b958ab4dbb33ae09a075a /drivers/char | |
parent | 35f621287ead686b66aa17aa605ed5d7c95883dc (diff) | |
download | linux-7a2f55d0be296c4e81fd782f3d6c43ed4ec7e265.tar.xz |
tpm, tpm: Implement usage counter for locality
Implement a usage counter for the (default) locality used by the TPM TIS
driver:
Request the locality from the TPM if it has not been claimed yet, otherwise
only increment the counter. Also release the locality if the counter is 0
otherwise only decrement the counter. Since in case of SPI the register
accesses are locked by means of the SPI bus mutex use a sleepable lock
(i.e. also a mutex) to ensure thread-safety of the counter which may be
accessed by both a userspace thread and the interrupt handler.
By doing this refactor the names of the amended functions to use a more
appropriate prefix.
Signed-off-by: Lino Sanfilippo <l.sanfilippo@kunbus.com>
Tested-by: Michael Niewöhner <linux@mniewoehner.de>
Tested-by: Jarkko Sakkinen <jarkko@kernel.org>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
Diffstat (limited to 'drivers/char')
-rw-r--r-- | drivers/char/tpm/tpm_tis_core.c | 63 | ||||
-rw-r--r-- | drivers/char/tpm/tpm_tis_core.h | 2 |
2 files changed, 47 insertions, 18 deletions
diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c index 717b81435cbd..b05c1ed51dd3 100644 --- a/drivers/char/tpm/tpm_tis_core.c +++ b/drivers/char/tpm/tpm_tis_core.c @@ -165,16 +165,27 @@ static bool check_locality(struct tpm_chip *chip, int l) return false; } -static int release_locality(struct tpm_chip *chip, int l) +static int __tpm_tis_relinquish_locality(struct tpm_tis_data *priv, int l) +{ + tpm_tis_write8(priv, TPM_ACCESS(l), TPM_ACCESS_ACTIVE_LOCALITY); + + return 0; +} + +static int tpm_tis_relinquish_locality(struct tpm_chip *chip, int l) { struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev); - tpm_tis_write8(priv, TPM_ACCESS(l), TPM_ACCESS_ACTIVE_LOCALITY); + mutex_lock(&priv->locality_count_mutex); + priv->locality_count--; + if (priv->locality_count == 0) + __tpm_tis_relinquish_locality(priv, l); + mutex_unlock(&priv->locality_count_mutex); return 0; } -static int request_locality(struct tpm_chip *chip, int l) +static int __tpm_tis_request_locality(struct tpm_chip *chip, int l) { struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev); unsigned long stop, timeout; @@ -215,6 +226,20 @@ again: return -1; } +static int tpm_tis_request_locality(struct tpm_chip *chip, int l) +{ + struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev); + int ret = 0; + + mutex_lock(&priv->locality_count_mutex); + if (priv->locality_count == 0) + ret = __tpm_tis_request_locality(chip, l); + if (!ret) + priv->locality_count++; + mutex_unlock(&priv->locality_count_mutex); + return ret; +} + static u8 tpm_tis_status(struct tpm_chip *chip) { struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev); @@ -682,7 +707,7 @@ static int probe_itpm(struct tpm_chip *chip) if (vendor != TPM_VID_INTEL) return 0; - if (request_locality(chip, 0) != 0) + if (tpm_tis_request_locality(chip, 0) != 0) return -EBUSY; rc = tpm_tis_send_data(chip, cmd_getticks, len); @@ -703,7 +728,7 @@ static int probe_itpm(struct tpm_chip *chip) out: tpm_tis_ready(chip); - release_locality(chip, priv->locality); + tpm_tis_relinquish_locality(chip, priv->locality); return rc; } @@ -792,14 +817,14 @@ static int tpm_tis_probe_irq_single(struct tpm_chip *chip, u32 intmask, } priv->irq = irq; - rc = request_locality(chip, 0); + rc = tpm_tis_request_locality(chip, 0); if (rc < 0) return rc; rc = tpm_tis_read8(priv, TPM_INT_VECTOR(priv->locality), &original_int_vec); if (rc < 0) { - release_locality(chip, priv->locality); + tpm_tis_relinquish_locality(chip, priv->locality); return rc; } @@ -838,7 +863,7 @@ restore_irqs: rc = -1; } - release_locality(chip, priv->locality); + tpm_tis_relinquish_locality(chip, priv->locality); return rc; } @@ -954,8 +979,8 @@ static const struct tpm_class_ops tpm_tis = { .req_complete_mask = TPM_STS_DATA_AVAIL | TPM_STS_VALID, .req_complete_val = TPM_STS_DATA_AVAIL | TPM_STS_VALID, .req_canceled = tpm_tis_req_canceled, - .request_locality = request_locality, - .relinquish_locality = release_locality, + .request_locality = tpm_tis_request_locality, + .relinquish_locality = tpm_tis_relinquish_locality, .clk_enable = tpm_tis_clkrun_enable, }; @@ -989,6 +1014,8 @@ int tpm_tis_core_init(struct device *dev, struct tpm_tis_data *priv, int irq, priv->timeout_min = TPM_TIMEOUT_USECS_MIN; priv->timeout_max = TPM_TIMEOUT_USECS_MAX; priv->phy_ops = phy_ops; + priv->locality_count = 0; + mutex_init(&priv->locality_count_mutex); dev_set_drvdata(&chip->dev, priv); @@ -1067,14 +1094,14 @@ int tpm_tis_core_init(struct device *dev, struct tpm_tis_data *priv, int irq, intmask &= ~TPM_GLOBAL_INT_ENABLE; - rc = request_locality(chip, 0); + rc = tpm_tis_request_locality(chip, 0); if (rc < 0) { rc = -ENODEV; goto out_err; } tpm_tis_write32(priv, TPM_INT_ENABLE(priv->locality), intmask); - release_locality(chip, 0); + tpm_tis_relinquish_locality(chip, 0); rc = tpm_chip_start(chip); if (rc) @@ -1108,13 +1135,13 @@ int tpm_tis_core_init(struct device *dev, struct tpm_tis_data *priv, int irq, * proper timeouts for the driver. */ - rc = request_locality(chip, 0); + rc = tpm_tis_request_locality(chip, 0); if (rc < 0) goto out_err; rc = tpm_get_timeouts(chip); - release_locality(chip, 0); + tpm_tis_relinquish_locality(chip, 0); if (rc) { dev_err(dev, "Could not get TPM timeouts and durations\n"); @@ -1134,11 +1161,11 @@ int tpm_tis_core_init(struct device *dev, struct tpm_tis_data *priv, int irq, dev_err(&chip->dev, FW_BUG "TPM interrupt not working, polling instead\n"); - rc = request_locality(chip, 0); + rc = tpm_tis_request_locality(chip, 0); if (rc < 0) goto out_err; disable_interrupts(chip); - release_locality(chip, 0); + tpm_tis_relinquish_locality(chip, 0); } } @@ -1205,13 +1232,13 @@ int tpm_tis_resume(struct device *dev) * an error code but for unknown reason it isn't handled. */ if (!(chip->flags & TPM_CHIP_FLAG_TPM2)) { - ret = request_locality(chip, 0); + ret = tpm_tis_request_locality(chip, 0); if (ret < 0) return ret; tpm1_do_selftest(chip); - release_locality(chip, 0); + tpm_tis_relinquish_locality(chip, 0); } return 0; diff --git a/drivers/char/tpm/tpm_tis_core.h b/drivers/char/tpm/tpm_tis_core.h index 19ef8c1a4142..e978f457fd4d 100644 --- a/drivers/char/tpm/tpm_tis_core.h +++ b/drivers/char/tpm/tpm_tis_core.h @@ -92,6 +92,8 @@ enum tpm_tis_flags { struct tpm_tis_data { u16 manufacturer_id; + struct mutex locality_count_mutex; + unsigned int locality_count; int locality; int irq; unsigned int int_mask; |