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Subject[PATCH v2 3/3] tpm, tpm_crb: runtime power management
Date
The register TPM_CRB_CTRL_REQ_0 contains bits goIdle and cmdReady for
invoking the chip to suspend and resume. This commit implements runtime
PM for tpm_crb by using these bits.

The legacy ACPI start (SMI + DMA) based devices do not support these
bits. Thus this functionality only is enabled only for CRB start (MMIO)
based devices.

Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
---
drivers/char/tpm/tpm-interface.c | 3 +++
drivers/char/tpm/tpm_crb.c | 50 ++++++++++++++++++++++++++++++++++++++--
2 files changed, 51 insertions(+), 2 deletions(-)

diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
index 5e3c1b6..3b85648 100644
--- a/drivers/char/tpm/tpm-interface.c
+++ b/drivers/char/tpm/tpm-interface.c
@@ -29,6 +29,7 @@
#include <linux/mutex.h>
#include <linux/spinlock.h>
#include <linux/freezer.h>
+#include <linux/pm_runtime.h>

#include "tpm.h"
#include "tpm_eventlog.h"
@@ -350,6 +351,7 @@ ssize_t tpm_transmit(struct tpm_chip *chip, const char *buf,
return -E2BIG;
}

+ pm_runtime_get_sync(chip->dev.parent);
mutex_lock(&chip->tpm_mutex);

rc = chip->ops->send(chip, (u8 *) buf, count);
@@ -394,6 +396,7 @@ out_recv:
"tpm_transmit: tpm_recv: error %zd\n", rc);
out:
mutex_unlock(&chip->tpm_mutex);
+ pm_runtime_put_sync(chip->dev.parent);
return rc;
}

diff --git a/drivers/char/tpm/tpm_crb.c b/drivers/char/tpm/tpm_crb.c
index 0c8ed7f..ef545eb 100644
--- a/drivers/char/tpm/tpm_crb.c
+++ b/drivers/char/tpm/tpm_crb.c
@@ -20,6 +20,7 @@
#include <linux/rculist.h>
#include <linux/module.h>
#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
#include "tpm.h"

#define ACPI_SIG_TPM2 "TPM2"
@@ -41,7 +42,6 @@ enum crb_ca_request {

enum crb_ca_status {
CRB_CA_STS_ERROR = BIT(0),
- CRB_CA_STS_TPM_IDLE = BIT(1),
};

enum crb_start {
@@ -83,7 +83,50 @@ struct crb_priv {
u8 __iomem *rsp;
};

-static SIMPLE_DEV_PM_OPS(crb_pm, tpm_pm_suspend, tpm_pm_resume);
+/* CONFIG_PM */
+static int __maybe_unused crb_runtime_suspend(struct device *dev)
+{
+ struct tpm_chip *chip = dev_get_drvdata(dev);
+ struct crb_priv *priv = dev_get_drvdata(&chip->dev);
+ u32 req;
+
+ if (priv->flags & CRB_FL_ACPI_START)
+ return 0;
+
+ req = ioread32(&priv->cca->req);
+ iowrite32(cpu_to_le32(req | CRB_CA_REQ_GO_IDLE), &priv->cca->req);
+ msleep(chip->timeout_c);
+
+ if (ioread32(&priv->cca->req) & CRB_CA_REQ_GO_IDLE)
+ return -ETIME;
+
+ return 0;
+}
+
+/* CONFIG_PM */
+static int __maybe_unused crb_runtime_resume(struct device *dev)
+{
+ struct tpm_chip *chip = dev_get_drvdata(dev);
+ struct crb_priv *priv = dev_get_drvdata(&chip->dev);
+ u32 req;
+
+ if (priv->flags & CRB_FL_ACPI_START)
+ return 0;
+
+ req = ioread32(&priv->cca->req);
+ iowrite32(cpu_to_le32(req | CRB_CA_REQ_CMD_READY), &priv->cca->req);
+ msleep(chip->timeout_c);
+
+ if (ioread32(&priv->cca->req) & CRB_CA_REQ_CMD_READY)
+ return -ETIME;
+
+ return 0;
+}
+
+static const struct dev_pm_ops crb_pm = {
+ SET_RUNTIME_PM_OPS(crb_runtime_suspend, crb_runtime_resume, NULL)
+ SET_SYSTEM_SLEEP_PM_OPS(tpm_pm_suspend, tpm_pm_resume)
+};

static u8 crb_status(struct tpm_chip *chip)
{
@@ -206,6 +249,8 @@ static int crb_init(struct acpi_device *device, struct crb_priv *priv)
if (IS_ERR(chip))
return PTR_ERR(chip);

+ pm_runtime_set_active(&device->dev);
+ pm_runtime_enable(&device->dev);
dev_set_drvdata(&chip->dev, priv);
chip->acpi_dev_handle = device->handle;
chip->flags = TPM_CHIP_FLAG_TPM2;
@@ -366,6 +411,7 @@ static int crb_acpi_remove(struct acpi_device *device)

tpm_chip_unregister(chip);

+ pm_runtime_disable(dev);
return 0;
}

--
2.7.4
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