On Wed, Sep 07, 2016 at 02:32:32PM +0300, Tomas Winkler wrote:
> 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>
I think I would add the dev_dbg line permanently with it that you have
in responses in this thread. There's been some unrelated bugs before
where this information in klog would have been very handy.
Reviewed-by: Jarkko Sakkinen <jarkko.sakki...@linux.intel.com>
/Jarkko
> ---
> drivers/char/tpm/tpm_crb.c | 37 +++++++++++++++++++++++++++----------
> 1 file changed, 27 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/char/tpm/tpm_crb.c b/drivers/char/tpm/tpm_crb.c
> index 98a7fdfe9936..cf9aab698dfe 100644
> --- a/drivers/char/tpm/tpm_crb.c
> +++ b/drivers/char/tpm/tpm_crb.c
> @@ -328,6 +328,7 @@ 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;
> @@ -335,15 +336,14 @@ static int crb_map_io(struct acpi_device *device,
> struct crb_priv *priv,
> int ret;
>
> INIT_LIST_HEAD(&resources);
> - ret = acpi_dev_get_resources(device, &resources, crb_check_resource,
> - &io_res);
> + ret = acpi_dev_get_resources(device, &resources,
> + crb_check_resource, &io_res);
> if (ret < 0)
> return ret;
> acpi_dev_free_resource_list(&resources);
>
> if (resource_type(&io_res) != IORESOURCE_MEM) {
> - dev_err(dev,
> - FW_BUG "TPM2 ACPI table does not define a memory
> resource\n");
> + dev_err(dev, FW_BUG "TPM2 ACPI table does not define a memory
> resource\n");
> return -EINVAL;
> }
>
> @@ -356,12 +356,24 @@ 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);
> +
> 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);
> @@ -369,7 +381,8 @@ 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
> @@ -377,10 +390,14 @@ 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->rsp = priv->cmd;
> +
> +out:
> + __crb_go_idle(dev, priv);
> return 0;
> }
>
> --
> 2.7.4
>
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