Re: [Linux-nvdimm] [PATCH 04/21] nd: create an 'nd_bus' from an 'nfit_desc'

From: Toshi Kani
Date: Tue Apr 21 2015 - 15:54:14 EST


On Fri, 2015-04-17 at 21:35 -0400, Dan Williams wrote:
:
> +
> +static int nd_mem_init(struct nd_bus *nd_bus)
> +{
> + struct nd_spa *nd_spa;
> +
> + /*
> + * For each SPA-DCR address range find its corresponding
> + * MEMDEV(s). From each MEMDEV find the corresponding DCR.
> + * Then, try to find a SPA-BDW and a corresponding BDW that
> + * references the DCR. Throw it all into an nd_mem object.
> + * Note, that BDWs are optional.
> + */
> + list_for_each_entry(nd_spa, &nd_bus->spas, list) {
> + u16 spa_index = readw(&nd_spa->nfit_spa->spa_index);
> + int type = nfit_spa_type(nd_spa->nfit_spa);
> + struct nd_mem *nd_mem, *found;
> + struct nd_memdev *nd_memdev;
> + u16 dcr_index;
> +
> + if (type != NFIT_SPA_DCR)
> + continue;

This function requires NFIT_SPA_DCR, SPA Range Structure with NVDIMM
Control Region GUID, for initializing an nd_mem object. However,
battery-backed DIMMs do not have such control region SPA. IIUC, the
NFIT spec does not require NFIT_SPA_DCR.

Can you change this function to work with NFIT_SPA_PM as well?

Thanks,
-Toshi


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