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>

1 files changed, 35 insertions, 36 deletions

diff --git a/drivers/acpi/nfit.c b/drivers/acpi/nfit.c
index ad6d8c6b777e..424b362e8fdc 100644
--- 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;