Re: [tpmdd-devel] [PATCH 2/3] tpm_crb: encapsulate crb_wait_for_reg_32
On Tue, Oct 11, 2016 at 10:21:03AM +, Winkler, Tomas wrote:
> > Encapsulated crb_wait_for_reg32() so that state changes in other CRB
> > registers
> > than TPM_CRB_CTRL_REQ_x can be waited.
> >
> > Signed-off-by: Jarkko Sakkinen
> > ---
> > drivers/char/tpm/tpm_crb.c | 40 +++-
> > 1 file changed, 23 insertions(+), 17 deletions(-)
> >
> > diff --git a/drivers/char/tpm/tpm_crb.c b/drivers/char/tpm/tpm_crb.c index
> > c34318b..45f53c2 100644
> > --- a/drivers/char/tpm/tpm_crb.c
> > +++ b/drivers/char/tpm/tpm_crb.c
> > @@ -121,6 +121,25 @@ static int __maybe_unused crb_go_idle(struct device
> > *dev, struct crb_priv *priv)
> > return 0;
> > }
> >
> > +static bool crb_wait_for_reg_32(u32 __iomem *reg, u32 mask, u32 value,
> > + unsigned long timeout)
> This is a boiler plate register polling function I would call it _poll_
> rather the _wait_
>
> > +{
> > + ktime_t start;
> > + ktime_t stop;
> > +
> > + start = ktime_get();
> > + stop = ktime_add(start, ms_to_ktime(timeout));
> > +
> > + do {
> > + if ((ioread32(reg) & mask) == value)
> I prefer the register value is synced to variable, this inlining is
> harder to add adhoc debug prints. Also you removed the debug print
> out that I know when this settled which is important for catching
> bugs.
I can add it but can you just briefly explain why the warning
is not enough?
> > + return true;
> > +
> > + usleep_range(50, 100);
> How do you know this is correct sleep time, I've tuned that for power
> gating I'm not sure you this fits also for locality.
Does it matter as long as it is less than for the timeout?
/Jarkko
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Re: [tpmdd-devel] [PATCH 2/3] tpm_crb: encapsulate crb_wait_for_reg_32
> Encapsulated crb_wait_for_reg32() so that state changes in other CRB registers
> than TPM_CRB_CTRL_REQ_x can be waited.
>
> Signed-off-by: Jarkko Sakkinen
> ---
> drivers/char/tpm/tpm_crb.c | 40 +++-
> 1 file changed, 23 insertions(+), 17 deletions(-)
>
> diff --git a/drivers/char/tpm/tpm_crb.c b/drivers/char/tpm/tpm_crb.c index
> c34318b..45f53c2 100644
> --- a/drivers/char/tpm/tpm_crb.c
> +++ b/drivers/char/tpm/tpm_crb.c
> @@ -121,6 +121,25 @@ static int __maybe_unused crb_go_idle(struct device
> *dev, struct crb_priv *priv)
> return 0;
> }
>
> +static bool crb_wait_for_reg_32(u32 __iomem *reg, u32 mask, u32 value,
> + unsigned long timeout)
This is a boiler plate register polling function I would call it _poll_ rather
the _wait_
> +{
> + ktime_t start;
> + ktime_t stop;
> +
> + start = ktime_get();
> + stop = ktime_add(start, ms_to_ktime(timeout));
> +
> + do {
> + if ((ioread32(reg) & mask) == value)
I prefer the register value is synced to variable, this inlining is harder to
add adhoc debug prints.
Also you removed the debug print out that I know when this settled which is
important for catching bugs.
> + return true;
> +
> + usleep_range(50, 100);
How do you know this is correct sleep time, I've tuned that for power gating
I'm not sure you this fits also for locality.
> + } while (ktime_before(ktime_get(), stop));
> +
> + return false;
> +}
> +
> /**
> * crb_cmd_ready - request tpm crb device to enter ready state
> *
> @@ -138,27 +157,14 @@ static int __maybe_unused crb_go_idle(struct device
> *dev, struct crb_priv *priv) static int __maybe_unused crb_cmd_ready(struct
> device *dev,
> struct crb_priv *priv)
> {
> - ktime_t stop, start;
> - u32 req;
> -
> if (priv->flags & CRB_FL_ACPI_START)
> return 0;
>
> iowrite32(CRB_CTRL_REQ_CMD_READY, &priv->regs_t->ctrl_req);
> -
> - start = ktime_get();
> - stop = ktime_add(start, ms_to_ktime(TPM2_TIMEOUT_C));
> - do {
> - req = ioread32(&priv->regs_t->ctrl_req);
> - if (!(req & CRB_CTRL_REQ_CMD_READY)) {
> - dev_dbg(dev, "cmdReady in %lld usecs\n",
> - ktime_to_us(ktime_sub(ktime_get(), start)));
> - return 0;
> - }
> - usleep_range(50, 100);
> - } while (ktime_before(ktime_get(), stop));
> -
> - if (ioread32(&priv->regs_t->ctrl_req) & CRB_CTRL_REQ_CMD_READY) {
> + if (!crb_wait_for_reg_32(&priv->regs_t->ctrl_req,
> + CRB_CTRL_REQ_CMD_READY /* mask */,
> + 0, /* value */
> + TPM2_TIMEOUT_C)) {
> dev_warn(dev, "cmdReady timed out\n");
> return -ETIME;
> }
> --
> 2.7.4
>
>
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[tpmdd-devel] [PATCH 2/3] tpm_crb: encapsulate crb_wait_for_reg_32
Encapsulated crb_wait_for_reg32() so that state changes in other CRB
registers than TPM_CRB_CTRL_REQ_x can be waited.
Signed-off-by: Jarkko Sakkinen
---
drivers/char/tpm/tpm_crb.c | 40 +++-
1 file changed, 23 insertions(+), 17 deletions(-)
diff --git a/drivers/char/tpm/tpm_crb.c b/drivers/char/tpm/tpm_crb.c
index c34318b..45f53c2 100644
--- a/drivers/char/tpm/tpm_crb.c
+++ b/drivers/char/tpm/tpm_crb.c
@@ -121,6 +121,25 @@ static int __maybe_unused crb_go_idle(struct device *dev,
struct crb_priv *priv)
return 0;
}
+static bool crb_wait_for_reg_32(u32 __iomem *reg, u32 mask, u32 value,
+ unsigned long timeout)
+{
+ ktime_t start;
+ ktime_t stop;
+
+ start = ktime_get();
+ stop = ktime_add(start, ms_to_ktime(timeout));
+
+ do {
+ if ((ioread32(reg) & mask) == value)
+ return true;
+
+ usleep_range(50, 100);
+ } while (ktime_before(ktime_get(), stop));
+
+ return false;
+}
+
/**
* crb_cmd_ready - request tpm crb device to enter ready state
*
@@ -138,27 +157,14 @@ static int __maybe_unused crb_go_idle(struct device *dev,
struct crb_priv *priv)
static int __maybe_unused crb_cmd_ready(struct device *dev,
struct crb_priv *priv)
{
- ktime_t stop, start;
- u32 req;
-
if (priv->flags & CRB_FL_ACPI_START)
return 0;
iowrite32(CRB_CTRL_REQ_CMD_READY, &priv->regs_t->ctrl_req);
-
- start = ktime_get();
- stop = ktime_add(start, ms_to_ktime(TPM2_TIMEOUT_C));
- do {
- req = ioread32(&priv->regs_t->ctrl_req);
- if (!(req & CRB_CTRL_REQ_CMD_READY)) {
- dev_dbg(dev, "cmdReady in %lld usecs\n",
- ktime_to_us(ktime_sub(ktime_get(), start)));
- return 0;
- }
- usleep_range(50, 100);
- } while (ktime_before(ktime_get(), stop));
-
- if (ioread32(&priv->regs_t->ctrl_req) & CRB_CTRL_REQ_CMD_READY) {
+ if (!crb_wait_for_reg_32(&priv->regs_t->ctrl_req,
+CRB_CTRL_REQ_CMD_READY /* mask */,
+0, /* value */
+TPM2_TIMEOUT_C)) {
dev_warn(dev, "cmdReady timed out\n");
return -ETIME;
}
--
2.7.4
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