Messages in this thread | | | From | Tomas Winkler <> | Date | Thu, 16 Jun 2016 23:26:48 +0300 | Subject | Re: [tpmdd-devel] [PATCH 3/3] tpm, tpm_crb: runtime power management |
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On Thu, Jun 16, 2016 at 10:57 PM, Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> wrote: > Hi Thomas, > > I'm on a vacation this week but I'll give you quick answers :) > > On Tue, Jun 14, 2016 at 04:14:58PM +0300, Tomas Winkler wrote: >> On Wed, Jun 8, 2016 at 2:02 AM, Jarkko Sakkinen >> <jarkko.sakkinen@linux.intel.com> wrote: >> > 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 | 62 ++++++++++++++++++++++++++++++++++++++-- >> > 2 files changed, 63 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 ca2cad9..71cc7cd 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 { >> > @@ -68,6 +68,8 @@ struct crb_control_area { >> > >> > enum crb_status { >> > CRB_STS_COMPLETE = BIT(0), >> > + CRB_STS_READY = BIT(1), >> > + CRB_STS_IDLE = BIT(2), >> > }; >> > >> > enum crb_flags { >> > @@ -81,9 +83,52 @@ struct crb_priv { >> > struct crb_control_area __iomem *cca; >> > u8 __iomem *cmd; >> > u8 __iomem *rsp; >> > + wait_queue_head_t idle_queue; >> >> >> I'm failing to find the code that is calling wake_up_interruptible(idle_queue); > > Ugh, my bad. This actually should not be declared at all. Will remove it > from the next version and NULL should be passed to wait_for_tpm_stat() > as the driver does not yet support interrupts (Haswell did not have > them, not sure about later gens). > > >> > }; >> > >> > -static SIMPLE_DEV_PM_OPS(crb_pm, tpm_pm_suspend, tpm_pm_resume); >> > +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); >> > + >> > + if (wait_for_tpm_stat(chip, CRB_STS_IDLE, chip->timeout_c, >> > + &priv->idle_queue, false)) >> > + dev_warn(&chip->dev, "idle timed out\n"); >> >> Unfortunately you cannot do that as there is an HW errata, the status >> register value might not be defined here during power transition >> You should poll for request CRB_CA_REQ_GO_IDLE goes to 0 as descried >> in the spec . only after that you can check for the status register >> (thought it's maybe not needed) > > And I do exactly what you are asking me to do. > >> > + >> > + return 0; >> > +} >> > + >> > +static int __maybe_unused crb_runtime_resume(struct device *dev) >> >> why this is marked unused, why just not compile it out? if the >> CONFIG_PM is not set? > > It is compiled out if it is unused. Why would you want to trash the code > with #ifdef cages if they are not necessary? I can add /* CONFIG_PM */ > before the function if that makes it cleaner.
I'm not sure about that, I believe it just suppresses warnings. You will need something --gc-sessions int the linker, I'm not sure this is used by kernel. > >> > +{ >> > + 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); >> > + >> > + if (wait_for_tpm_stat(chip, CRB_STS_READY, chip->timeout_c, >> > + &priv->idle_queue, false)) >> > + dev_warn(&chip->dev, "wake timed out\n"); >> >> Same here, you should wait for CRB_CA_REQ_CMD_READ to get cleared, >> only after that it is safe to check the status register. > > It does exactly that. I'm not using CRB status register for anything. > >> > + >> > + 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) >> > { >> > @@ -94,6 +139,14 @@ static u8 crb_status(struct tpm_chip *chip) >> > CRB_START_INVOKE) >> > sts |= CRB_STS_COMPLETE; >> > >> > + if ((ioread32(&priv->cca->req) & CRB_CA_REQ_CMD_READY) != >> > + CRB_CA_REQ_CMD_READY) >> > + sts |= CRB_STS_READY; >> >> There is meaning for checking this w/o the actual transition i.e. >> setting the before > > I'm not sure what you are trying to say.
Sorry, my bad, it should be: There is NO meaning for checking CRB_CA_REQ_CMD_READY is 0 if this wasn't asserted before, In interrupt language it's not edge sensitive not level sensitive
Tomas
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