Message-Id: <20180324183935.20784-1-tomas.winkler@intel.com>
Date:   Sat, 24 Mar 2018 21:39:35 +0300
From:   Tomas Winkler <tomas.winkler@...el.com>
To:     Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>,
        Jason Gunthorpe <jgg@...pe.ca>
Cc:     Alexander Usyskin <alexander.usyskin@...el.com>,
        linux-integrity@...r.kernel.org,
        linux-security-module@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        "Winkler, Tomas" <tomas.winkler@...el.com>
Subject: [PATCH V4] tpm: separate cmd_ready/go_idle from runtime_pm

From: "Winkler, Tomas" <tomas.winkler@...el.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@...el.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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