nfit: fix multi-interface dimm handling, acpi6.1 compatibility

ACPI 6.1 clarified that multi-interface dimms require multiple control
region entries (DCRs) per dimm.  Previously we were assuming that a
control region is only present when block-data-windows are present.
This implementation was done with an eye to be compatibility with the
looser ACPI 6.0 interpretation of this table.

1/ When coalescing the memory device (MEMDEV) tables for a single dimm,
coalesce on device_handle rather than control region index.

2/ Whenever we disocver a control region with non-zero block windows
re-scan for block-data-window (BDW) entries.

We may need to revisit this if a DIMM ever implements a format interface
outside of blk or pmem, but that is not on the foreseeable horizon.

Cc: <stable@vger.kernel.org>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

diff --git a/drivers/acpi/nfit.c b/drivers/acpi/nfit.c
index ad6d8c6b777e7c83885cc3f854396808153653f3..424b362e8fdc447ca2e3fdae45457e3bb7f1dde0 100644 (file)
--- a/drivers/acpi/nfit.c
+++ b/drivers/acpi/nfit.c
@@ -469,37 +469,16 @@ static void nfit_mem_find_spa_bdw(struct acpi_nfit_desc *acpi_desc,
        nfit_mem->bdw = NULL;
 }
 
-static int nfit_mem_add(struct acpi_nfit_desc *acpi_desc,
+static void nfit_mem_init_bdw(struct acpi_nfit_desc *acpi_desc,
                struct nfit_mem *nfit_mem, struct acpi_nfit_system_address *spa)
 {
        u16 dcr = __to_nfit_memdev(nfit_mem)->region_index;
        struct nfit_memdev *nfit_memdev;
        struct nfit_flush *nfit_flush;
-       struct nfit_dcr *nfit_dcr;
        struct nfit_bdw *nfit_bdw;
        struct nfit_idt *nfit_idt;
        u16 idt_idx, range_index;
 
-       list_for_each_entry(nfit_dcr, &acpi_desc->dcrs, list) {
-               if (nfit_dcr->dcr->region_index != dcr)
-                       continue;
-               nfit_mem->dcr = nfit_dcr->dcr;
-               break;
-       }
-
-       if (!nfit_mem->dcr) {
-               dev_dbg(acpi_desc->dev, "SPA %d missing:%s%s\n",
-                               spa->range_index, __to_nfit_memdev(nfit_mem)
-                               ? "" : " MEMDEV", nfit_mem->dcr ? "" : " DCR");
-               return -ENODEV;
-       }
-
-       /*
-        * We've found enough to create an nvdimm, optionally
-        * find an associated BDW
-        */
-       list_add(&nfit_mem->list, &acpi_desc->dimms);
-
        list_for_each_entry(nfit_bdw, &acpi_desc->bdws, list) {
                if (nfit_bdw->bdw->region_index != dcr)
                        continue;
@@ -508,12 +487,12 @@ static int nfit_mem_add(struct acpi_nfit_desc *acpi_desc,
        }
 
        if (!nfit_mem->bdw)
-               return 0;
+               return;
 
        nfit_mem_find_spa_bdw(acpi_desc, nfit_mem);
 
        if (!nfit_mem->spa_bdw)
-               return 0;
+               return;
 
        range_index = nfit_mem->spa_bdw->range_index;
        list_for_each_entry(nfit_memdev, &acpi_desc->memdevs, list) {
@@ -538,8 +517,6 @@ static int nfit_mem_add(struct acpi_nfit_desc *acpi_desc,
                }
                break;
        }
-
-       return 0;
 }
 
 static int nfit_mem_dcr_init(struct acpi_nfit_desc *acpi_desc,
@@ -548,7 +525,6 @@ static int nfit_mem_dcr_init(struct acpi_nfit_desc *acpi_desc,
        struct nfit_mem *nfit_mem, *found;
        struct nfit_memdev *nfit_memdev;
        int type = nfit_spa_type(spa);
-       u16 dcr;
 
        switch (type) {
        case NFIT_SPA_DCR:
@@ -559,14 +535,18 @@ static int nfit_mem_dcr_init(struct acpi_nfit_desc *acpi_desc,
        }
 
        list_for_each_entry(nfit_memdev, &acpi_desc->memdevs, list) {
-               int rc;
+               struct nfit_dcr *nfit_dcr;
+               u32 device_handle;
+               u16 dcr;
 
                if (nfit_memdev->memdev->range_index != spa->range_index)
                        continue;
                found = NULL;
                dcr = nfit_memdev->memdev->region_index;
+               device_handle = nfit_memdev->memdev->device_handle;
                list_for_each_entry(nfit_mem, &acpi_desc->dimms, list)
-                       if (__to_nfit_memdev(nfit_mem)->region_index == dcr) {
+                       if (__to_nfit_memdev(nfit_mem)->device_handle
+                                       == device_handle) {
                                found = nfit_mem;
                                break;
                        }
@@ -579,6 +559,31 @@ static int nfit_mem_dcr_init(struct acpi_nfit_desc *acpi_desc,
                        if (!nfit_mem)
                                return -ENOMEM;
                        INIT_LIST_HEAD(&nfit_mem->list);
+                       list_add(&nfit_mem->list, &acpi_desc->dimms);
+               }
+
+               list_for_each_entry(nfit_dcr, &acpi_desc->dcrs, list) {
+                       if (nfit_dcr->dcr->region_index != dcr)
+                               continue;
+                       /*
+                        * Record the control region for the dimm.  For
+                        * the ACPI 6.1 case, where there are separate
+                        * control regions for the pmem vs blk
+                        * interfaces, be sure to record the extended
+                        * blk details.
+                        */
+                       if (!nfit_mem->dcr)
+                               nfit_mem->dcr = nfit_dcr->dcr;
+                       else if (nfit_mem->dcr->windows == 0
+                                       && nfit_dcr->dcr->windows)
+                               nfit_mem->dcr = nfit_dcr->dcr;
+                       break;
+               }
+
+               if (dcr && !nfit_mem->dcr) {
+                       dev_err(acpi_desc->dev, "SPA %d missing DCR %d\n",
+                                       spa->range_index, dcr);
+                       return -ENODEV;
                }
 
                if (type == NFIT_SPA_DCR) {
@@ -595,6 +600,7 @@ static int nfit_mem_dcr_init(struct acpi_nfit_desc *acpi_desc,
                                nfit_mem->idt_dcr = nfit_idt->idt;
                                break;
                        }
+                       nfit_mem_init_bdw(acpi_desc, nfit_mem, spa);
                } else {
                        /*
                         * A single dimm may belong to multiple SPA-PM
@@ -603,13 +609,6 @@ static int nfit_mem_dcr_init(struct acpi_nfit_desc *acpi_desc,
                         */
                        nfit_mem->memdev_pmem = nfit_memdev->memdev;
                }
-
-               if (found)
-                       continue;
-
-               rc = nfit_mem_add(acpi_desc, nfit_mem, spa);
-               if (rc)
-                       return rc;
        }
 
        return 0;