On Mon, Mar 6, 2017 at 4:25 PM, Linda Knippers <[email protected]> wrote:
> Provide the ability to request a default DSM family. If it is not
> supported, then fall back to the normal discovery order.
>
> This is helpful for testing platforms that support multiple DSM families.
> It will also allow administrators to request the DSM family that their
> management tools support, which may not be the first one found using
> the current discovery order.
>
> Signed-off-by: Linda Knippers <[email protected]>
> ---
> drivers/acpi/nfit/core.c | 26 ++++++++++++++++++++++----
> 1 file changed, 22 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/acpi/nfit/core.c b/drivers/acpi/nfit/core.c
> index 97d42ff..78c46a7 100644
> --- a/drivers/acpi/nfit/core.c
> +++ b/drivers/acpi/nfit/core.c
> @@ -55,6 +55,11 @@
> module_param(override_dsm_mask, ulong, S_IRUGO);
> MODULE_PARM_DESC(override_dsm_mask, "Bitmask of allowed NVDIMM DSM
> functions");
>
> +static int default_dsm_family = -1;
> +module_param(default_dsm_family, int, S_IRUGO);
> +MODULE_PARM_DESC(default_dsm_family,
> + "Try this DSM type first when identifying NVDIMM family");
> +
> LIST_HEAD(acpi_descs);
> DEFINE_MUTEX(acpi_desc_lock);
>
> @@ -1371,7 +1376,7 @@ static int acpi_nfit_add_dimm(struct acpi_nfit_desc
> *acpi_desc,
> struct device *dev = acpi_desc->dev;
> unsigned long dsm_mask;
> const u8 *uuid;
> - int i;
> + int i = -1;
>
> /* nfit test assumes 1:1 relationship between commands and dsms */
> nfit_mem->dsm_mask = acpi_desc->dimm_cmd_force_en;
> @@ -1399,10 +1404,23 @@ static int acpi_nfit_add_dimm(struct acpi_nfit_desc
> *acpi_desc,
> * Until standardization materializes we need to consider 4
> * different command sets. Note, that checking for function0 (bit0)
> * tells us if any commands are reachable through this uuid.
> + * First check for a requested default.
> */
> - for (i = NVDIMM_FAMILY_INTEL; i <= NVDIMM_FAMILY_MSFT; i++)
> - if (acpi_check_dsm(adev_dimm->handle, to_nfit_uuid(i), 1, 1))
> - break;
> + if (default_dsm_family >= NVDIMM_FAMILY_INTEL &&
> + default_dsm_family <= NVDIMM_FAMILY_MSFT) {
> + if (acpi_check_dsm(adev_dimm->handle,
> + to_nfit_uuid(default_dsm_family), 1, 1))
> + i = default_dsm_family;
> + else
> + dev_dbg(dev, "default_dsm_family %d not supported\n",
> + default_dsm_family);
> + }
> + if (i == -1) {
> + for (i = NVDIMM_FAMILY_INTEL; i <= NVDIMM_FAMILY_MSFT; i++)
> + if (acpi_check_dsm(adev_dimm->handle, to_nfit_uuid(i),
> + 1, 1))
> + break;
> + }
I think we can make this simpler and more deterministic with a "force"
option? Something like:
@@ -1397,8 +1397,12 @@ static int acpi_nfit_add_dimm(struct
acpi_nfit_desc *acpi_desc,
* tells us if any commands are reachable through this uuid.
*/
for (i = NVDIMM_FAMILY_INTEL; i <= NVDIMM_FAMILY_MSFT; i++)
- if (acpi_check_dsm(adev_dimm->handle, to_nfit_uuid(i), 1, 1))
- break;
+ if (acpi_check_dsm(adev_dimm->handle, to_nfit_uuid(i), 1, 1)) {
+ if (force_dsm_family < 0)
+ break;
+ else if (i == force_dsm_family)
+ break;
+ }
/* limit the supported commands to those that are publicly documented */
nfit_mem->family = i;
...because the user specifying the override should know ahead of time
if that family is available, and we should fail the detection
otherwise.
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