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Subject[PATCH V4] tpm: separate cmd_ready/go_idle from runtime_pm
Date
From: "Winkler, Tomas" <tomas.winkler@intel.com>

We cannot use go_idle cmd_ready commands via runtime_pm handles
as with the introduction of localities this is no longer an optional
feature, while runtime pm can be not enabled.
Though cmd_ready/go_idle provides power saving feature, it's also part of
TPM2 protocol and should be called explicitly.
This patch exposes cmd_read/go_idle via tpm class ops and removes
runtime pm support as it is not used by any driver.

tpm_crb no longer needs own power saving functions and can drop using
tpm_pm_suspend/resume.

Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
---
V2-3:resent
V4: 1. Use tpm_pm_suspend/resume in tpm_crb
2. Drop cmd_ready/go_idle around tpm_chip_register, as there is no
usage counter like in runtime_pm.

drivers/char/tpm/tpm-interface.c | 15 ++++--
drivers/char/tpm/tpm_crb.c | 100 ++++++++++-----------------------------
include/linux/tpm.h | 2 +
3 files changed, 38 insertions(+), 79 deletions(-)

diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
index c43a9e28995e..1dc4961c42c6 100644
--- a/drivers/char/tpm/tpm-interface.c
+++ b/drivers/char/tpm/tpm-interface.c
@@ -29,7 +29,6 @@
#include <linux/mutex.h>
#include <linux/spinlock.h>
#include <linux/freezer.h>
-#include <linux/pm_runtime.h>
#include <linux/tpm_eventlog.h>

#include "tpm.h"
@@ -455,8 +454,11 @@ static ssize_t tpm_try_transmit(struct tpm_chip *chip,
goto out_no_locality;
}

- if (chip->dev.parent)
- pm_runtime_get_sync(chip->dev.parent);
+ if (chip->ops->cmd_ready) {
+ rc = chip->ops->cmd_ready(chip);
+ if (rc)
+ goto out;
+ }

rc = tpm2_prepare_space(chip, space, ordinal, buf);
if (rc)
@@ -518,8 +520,11 @@ static ssize_t tpm_try_transmit(struct tpm_chip *chip,
rc = tpm2_commit_space(chip, space, ordinal, buf, &len);

out:
- if (chip->dev.parent)
- pm_runtime_put_sync(chip->dev.parent);
+ if (chip->ops->go_idle) {
+ rc = chip->ops->go_idle(chip);
+ if (rc)
+ goto out;
+ }

if (need_locality)
tpm_relinquish_locality(chip);
diff --git a/drivers/char/tpm/tpm_crb.c b/drivers/char/tpm/tpm_crb.c
index 7f78482cd157..1b11c9b8908f 100644
--- a/drivers/char/tpm/tpm_crb.c
+++ b/drivers/char/tpm/tpm_crb.c
@@ -132,7 +132,7 @@ static bool crb_wait_for_reg_32(u32 __iomem *reg, u32 mask, u32 value,
}

/**
- * crb_go_idle - request tpm crb device to go the idle state
+ * __crb_go_idle - request tpm crb device to go the idle state
*
* @dev: crb device
* @priv: crb private data
@@ -147,7 +147,7 @@ static bool crb_wait_for_reg_32(u32 __iomem *reg, u32 mask, u32 value,
*
* Return: 0 always
*/
-static int crb_go_idle(struct device *dev, struct crb_priv *priv)
+static int __crb_go_idle(struct device *dev, struct crb_priv *priv)
{
if ((priv->sm == ACPI_TPM2_START_METHOD) ||
(priv->sm == ACPI_TPM2_COMMAND_BUFFER_WITH_START_METHOD) ||
@@ -166,8 +166,16 @@ static int crb_go_idle(struct device *dev, struct crb_priv *priv)
return 0;
}

+static int crb_go_idle(struct tpm_chip *chip)
+{
+ struct device *dev = &chip->dev;
+ struct crb_priv *priv = dev_get_drvdata(dev);
+
+ return __crb_go_idle(dev, priv);
+}
+
/**
- * crb_cmd_ready - request tpm crb device to enter ready state
+ * __crb_cmd_ready - request tpm crb device to enter ready state
*
* @dev: crb device
* @priv: crb private data
@@ -181,7 +189,7 @@ static int crb_go_idle(struct device *dev, struct crb_priv *priv)
*
* Return: 0 on success -ETIME on timeout;
*/
-static int crb_cmd_ready(struct device *dev, struct crb_priv *priv)
+static int __crb_cmd_ready(struct device *dev, struct crb_priv *priv)
{
if ((priv->sm == ACPI_TPM2_START_METHOD) ||
(priv->sm == ACPI_TPM2_COMMAND_BUFFER_WITH_START_METHOD) ||
@@ -200,6 +208,14 @@ static int crb_cmd_ready(struct device *dev, struct crb_priv *priv)
return 0;
}

+static int crb_cmd_ready(struct tpm_chip *chip)
+{
+ struct device *dev = &chip->dev;
+ struct crb_priv *priv = dev_get_drvdata(dev);
+
+ return __crb_cmd_ready(dev, priv);
+}
+
static int __crb_request_locality(struct device *dev,
struct crb_priv *priv, int loc)
{
@@ -401,6 +417,8 @@ static const struct tpm_class_ops tpm_crb = {
.send = crb_send,
.cancel = crb_cancel,
.req_canceled = crb_req_canceled,
+ .go_idle = crb_go_idle,
+ .cmd_ready = crb_cmd_ready,
.request_locality = crb_request_locality,
.relinquish_locality = crb_relinquish_locality,
.req_complete_mask = CRB_DRV_STS_COMPLETE,
@@ -518,7 +536,7 @@ static int crb_map_io(struct acpi_device *device, struct crb_priv *priv,
* PTT HW bug w/a: wake up the device to access
* possibly not retained registers.
*/
- ret = crb_cmd_ready(dev, priv);
+ ret = __crb_cmd_ready(dev, priv);
if (ret)
return ret;

@@ -563,7 +581,7 @@ static int crb_map_io(struct acpi_device *device, struct crb_priv *priv,
if (!ret)
priv->cmd_size = cmd_size;

- crb_go_idle(dev, priv);
+ __crb_go_idle(dev, priv);

__crb_relinquish_locality(dev, priv, 0);

@@ -624,32 +642,7 @@ static int crb_acpi_add(struct acpi_device *device)
chip->acpi_dev_handle = device->handle;
chip->flags = TPM_CHIP_FLAG_TPM2;

- rc = __crb_request_locality(dev, priv, 0);
- if (rc)
- return rc;
-
- rc = crb_cmd_ready(dev, priv);
- if (rc)
- goto out;
-
- pm_runtime_get_noresume(dev);
- pm_runtime_set_active(dev);
- pm_runtime_enable(dev);
-
- rc = tpm_chip_register(chip);
- if (rc) {
- crb_go_idle(dev, priv);
- pm_runtime_put_noidle(dev);
- pm_runtime_disable(dev);
- goto out;
- }
-
- pm_runtime_put_sync(dev);
-
-out:
- __crb_relinquish_locality(dev, priv, 0);
-
- return rc;
+ return tpm_chip_register(chip);
}

static int crb_acpi_remove(struct acpi_device *device)
@@ -659,52 +652,11 @@ static int crb_acpi_remove(struct acpi_device *device)

tpm_chip_unregister(chip);

- pm_runtime_disable(dev);
-
return 0;
}

-static int __maybe_unused crb_pm_runtime_suspend(struct device *dev)
-{
- struct tpm_chip *chip = dev_get_drvdata(dev);
- struct crb_priv *priv = dev_get_drvdata(&chip->dev);
-
- return crb_go_idle(dev, priv);
-}
-
-static int __maybe_unused crb_pm_runtime_resume(struct device *dev)
-{
- struct tpm_chip *chip = dev_get_drvdata(dev);
- struct crb_priv *priv = dev_get_drvdata(&chip->dev);
-
- return crb_cmd_ready(dev, priv);
-}
-
-static int __maybe_unused crb_pm_suspend(struct device *dev)
-{
- int ret;
-
- ret = tpm_pm_suspend(dev);
- if (ret)
- return ret;
-
- return crb_pm_runtime_suspend(dev);
-}
-
-static int __maybe_unused crb_pm_resume(struct device *dev)
-{
- int ret;
-
- ret = crb_pm_runtime_resume(dev);
- if (ret)
- return ret;
-
- return tpm_pm_resume(dev);
-}
-
static const struct dev_pm_ops crb_pm = {
- SET_SYSTEM_SLEEP_PM_OPS(crb_pm_suspend, crb_pm_resume)
- SET_RUNTIME_PM_OPS(crb_pm_runtime_suspend, crb_pm_runtime_resume, NULL)
+ SET_SYSTEM_SLEEP_PM_OPS(tpm_pm_suspend, tpm_pm_resume)
};

static const struct acpi_device_id crb_device_ids[] = {
diff --git a/include/linux/tpm.h b/include/linux/tpm.h
index 06639fb6ab85..8eb5e5ebe136 100644
--- a/include/linux/tpm.h
+++ b/include/linux/tpm.h
@@ -43,6 +43,8 @@ struct tpm_class_ops {
u8 (*status) (struct tpm_chip *chip);
bool (*update_timeouts)(struct tpm_chip *chip,
unsigned long *timeout_cap);
+ int (*go_idle)(struct tpm_chip *chip);
+ int (*cmd_ready)(struct tpm_chip *chip);
int (*request_locality)(struct tpm_chip *chip, int loc);
int (*relinquish_locality)(struct tpm_chip *chip, int loc);
void (*clk_enable)(struct tpm_chip *chip, bool value);
--
2.14.3
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