On Sat, Oct 08, 2016 at 02:59:37PM +0300, Tomas Winkler wrote:
> From: "Winkler, Tomas" <tomas.wink...@intel.com>
>
> There is a HW bug in Skylake, Kabylake, and Broxton PCH Intel PTT device,
> where most of the registers in the control area except START, REQUEST,
> CANCEL, and LOC_CTRL lost retention when the device is in the idle state.
> Hence we need to bring the device to ready state before accessing the other
> registers. The fix brings device to ready state before trying to read
> command and response buffer addresses in order to remap the for access.
>
> Signed-off-by: Tomas Winkler <tomas.wink...@intel.com>
> ---
> V2: cmd read need to be called also before crb_init as this will run
> self test.
> V3: resend.
> V4: add Kabylake to the list of effected platforms
>
> drivers/char/tpm/tpm_crb.c | 47
> ++++++++++++++++++++++++++++++++++++++--------
> 1 file changed, 39 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/char/tpm/tpm_crb.c b/drivers/char/tpm/tpm_crb.c
> index 0f3b3f3d12d3..4eb96b85c653 100644
> --- a/drivers/char/tpm/tpm_crb.c
> +++ b/drivers/char/tpm/tpm_crb.c
> @@ -319,6 +319,7 @@ static int crb_map_io(struct acpi_device *device, struct
> crb_priv *priv,
> struct list_head resources;
> struct resource io_res;
> struct device *dev = &device->dev;
> + u32 pa_high, pa_low;
> u64 cmd_pa;
> u32 cmd_size;
> u64 rsp_pa;
> @@ -346,12 +347,27 @@ static int crb_map_io(struct acpi_device *device,
> struct crb_priv *priv,
> if (IS_ERR(priv->cca))
> return PTR_ERR(priv->cca);
>
> - cmd_pa = ((u64) ioread32(&priv->cca->cmd_pa_high) << 32) |
> - (u64) ioread32(&priv->cca->cmd_pa_low);
> + /*
> + * PTT HW bug w/a: wake up the device to access
> + * possibly not retained registers.
> + */
> + ret = crb_cmd_ready(dev, priv);
> + if (ret)
> + return ret;
> +
> + pa_high = ioread32(&priv->cca->cmd_pa_high);
> + pa_low = ioread32(&priv->cca->cmd_pa_low);
> + cmd_pa = ((u64)pa_high << 32) | pa_low;
> cmd_size = ioread32(&priv->cca->cmd_size);
> +
> + dev_dbg(dev, "cmd_hi = %X cmd_low = %X cmd_size %X\n",
> + pa_high, pa_low, cmd_size);
> +
> priv->cmd = crb_map_res(dev, priv, &io_res, cmd_pa, cmd_size);
> - if (IS_ERR(priv->cmd))
> - return PTR_ERR(priv->cmd);
> + if (IS_ERR(priv->cmd)) {
> + ret = PTR_ERR(priv->cmd);
> + goto out;
> + }
>
> memcpy_fromio(&rsp_pa, &priv->cca->rsp_pa, 8);
> rsp_pa = le64_to_cpu(rsp_pa);
> @@ -359,7 +375,8 @@ static int crb_map_io(struct acpi_device *device, struct
> crb_priv *priv,
>
> if (cmd_pa != rsp_pa) {
> priv->rsp = crb_map_res(dev, priv, &io_res, rsp_pa, rsp_size);
> - return PTR_ERR_OR_ZERO(priv->rsp);
> + ret = PTR_ERR_OR_ZERO(priv->rsp);
> + goto out;
> }
>
> /* According to the PTP specification, overlapping command and response
> @@ -367,12 +384,18 @@ static int crb_map_io(struct acpi_device *device,
> struct crb_priv *priv,
> */
> if (cmd_size != rsp_size) {
> dev_err(dev, FW_BUG "overlapping command and response buffer
> sizes are not identical");
> - return -EINVAL;
> + ret = -EINVAL;
> + goto out;
> }
> +
> priv->cmd_size = cmd_size;
>
> priv->rsp = priv->cmd;
> - return 0;
> +
> +out:
> + crb_go_idle(dev, priv);
> +
> + return ret;
> }
>
> static int crb_acpi_add(struct acpi_device *device)
> @@ -416,7 +439,15 @@ static int crb_acpi_add(struct acpi_device *device)
> if (rc)
> return rc;
>
> - return crb_init(device, priv);
> + rc = crb_cmd_ready(dev, priv);
> + if (rc)
> + return rc;
I cannot find any valid reason why crb_map_io calls crb_go_idle in the
except in the case of a failure. This is something I complained earlier.
A minor thing but the extra crb_cmd_ready is basically clutter to the
initialization.
/Jarkko
