lightnvm: introduce mlc lower page table mappings

NAND MLC memories have both lower and upper pages. When programming,
both of these must be written, before data can be read. However,
these lower and upper pages might not placed at even and odd flash
pages, but can be skipped. Therefore each flash memory has its lower
pages defined, which can then be used when programming and to know when
padding are necessary.

This patch implements the lower page definition in the specification,
and exposes it through a simple lookup table at dev->lptbl.

Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@fb.com>

diff --git a/drivers/lightnvm/core.c b/drivers/lightnvm/core.c
index 5199c12fead059eeadbe1db69a57564675555a23..1f302cc73e0ba7a9d71a07e240ba27ef90f906aa 100644 (file)
--- a/drivers/lightnvm/core.c
+++ b/drivers/lightnvm/core.c
@@ -362,6 +362,51 @@ int nvm_submit_ppa(struct nvm_dev *dev, struct ppa_addr *ppa, int nr_ppas,
 }
 EXPORT_SYMBOL(nvm_submit_ppa);
 
+static int nvm_init_slc_tbl(struct nvm_dev *dev, struct nvm_id_group *grp)
+{
+       int i;
+
+       dev->lps_per_blk = dev->pgs_per_blk;
+       dev->lptbl = kcalloc(dev->lps_per_blk, sizeof(int), GFP_KERNEL);
+       if (!dev->lptbl)
+               return -ENOMEM;
+
+       /* Just a linear array */
+       for (i = 0; i < dev->lps_per_blk; i++)
+               dev->lptbl[i] = i;
+
+       return 0;
+}
+
+static int nvm_init_mlc_tbl(struct nvm_dev *dev, struct nvm_id_group *grp)
+{
+       int i, p;
+       struct nvm_id_lp_mlc *mlc = &grp->lptbl.mlc;
+
+       if (!mlc->num_pairs)
+               return 0;
+
+       dev->lps_per_blk = mlc->num_pairs;
+       dev->lptbl = kcalloc(dev->lps_per_blk, sizeof(int), GFP_KERNEL);
+       if (!dev->lptbl)
+               return -ENOMEM;
+
+       /* The lower page table encoding consists of a list of bytes, where each
+        * has a lower and an upper half. The first half byte maintains the
+        * increment value and every value after is an offset added to the
+        * previous incrementation value */
+       dev->lptbl[0] = mlc->pairs[0] & 0xF;
+       for (i = 1; i < dev->lps_per_blk; i++) {
+               p = mlc->pairs[i >> 1];
+               if (i & 0x1) /* upper */
+                       dev->lptbl[i] = dev->lptbl[i - 1] + ((p & 0xF0) >> 4);
+               else /* lower */
+                       dev->lptbl[i] = dev->lptbl[i - 1] + (p & 0xF);
+       }
+
+       return 0;
+}
+
 static int nvm_core_init(struct nvm_dev *dev)
 {
        struct nvm_id *id = &dev->identity;
@@ -387,11 +432,23 @@ static int nvm_core_init(struct nvm_dev *dev)
                return -EINVAL;
        }
 
-       if (grp->fmtype != 0 && grp->fmtype != 1) {
+       switch (grp->fmtype) {
+       case NVM_ID_FMTYPE_SLC:
+               if (nvm_init_slc_tbl(dev, grp))
+                       return -ENOMEM;
+               break;
+       case NVM_ID_FMTYPE_MLC:
+               if (nvm_init_mlc_tbl(dev, grp))
+                       return -ENOMEM;
+               break;
+       default:
                pr_err("nvm: flash type not supported\n");
                return -EINVAL;
        }
 
+       if (!dev->lps_per_blk)
+               pr_info("nvm: lower page programming table missing\n");
+
        if (grp->mpos & 0x020202)
                dev->plane_mode = NVM_PLANE_DOUBLE;
        if (grp->mpos & 0x040404)
@@ -420,6 +477,8 @@ static void nvm_free(struct nvm_dev *dev)
 
        if (dev->mt)
                dev->mt->unregister_mgr(dev);
+
+       kfree(dev->lptbl);
 }
 
 static int nvm_init(struct nvm_dev *dev)

diff --git a/drivers/nvme/host/lightnvm.c b/drivers/nvme/host/lightnvm.c
index b112f022dee2e771fa90aaae77091f4d506af70e..215c02512811a9fcfd29ef54811ad9cd0f191354 100644 (file)
--- a/drivers/nvme/host/lightnvm.c
+++ b/drivers/nvme/host/lightnvm.c
@@ -146,6 +146,16 @@ struct nvme_nvm_command {
        };
 };
 
+struct nvme_nvm_lp_mlc {
+       __u16                   num_pairs;
+       __u8                    pairs[886];
+};
+
+struct nvme_nvm_lp_tbl {
+       __u8                    id[8];
+       struct nvme_nvm_lp_mlc  mlc;
+};
+
 struct nvme_nvm_id_group {
        __u8                    mtype;
        __u8                    fmtype;
@@ -169,7 +179,8 @@ struct nvme_nvm_id_group {
        __le32                  mpos;
        __le32                  mccap;
        __le16                  cpar;
-       __u8                    reserved[906];
+       __u8                    reserved[10];
+       struct nvme_nvm_lp_tbl lptbl;
 } __packed;
 
 struct nvme_nvm_addr_format {
@@ -266,6 +277,15 @@ static int init_grps(struct nvm_id *nvm_id, struct nvme_nvm_id *nvme_nvm_id)
                dst->mccap = le32_to_cpu(src->mccap);
 
                dst->cpar = le16_to_cpu(src->cpar);
+
+               if (dst->fmtype == NVM_ID_FMTYPE_MLC) {
+                       memcpy(dst->lptbl.id, src->lptbl.id, 8);
+                       dst->lptbl.mlc.num_pairs =
+                                       le16_to_cpu(src->lptbl.mlc.num_pairs);
+                       /* 4 bits per pair */
+                       memcpy(dst->lptbl.mlc.pairs, src->lptbl.mlc.pairs,
+                                               dst->lptbl.mlc.num_pairs >> 1);
+               }
        }
 
        return 0;

diff --git a/include/linux/lightnvm.h b/include/linux/lightnvm.h
index b90d28344e3d7d5c78bf53cc91b5109d7f526b32..678fd91a1f99cc96041d8e6fdb488031df8abd88 100644 (file)
--- a/include/linux/lightnvm.h
+++ b/include/linux/lightnvm.h
@@ -67,6 +67,20 @@ enum {
        NVM_ID_CAP_CMD_SUSPEND  = 0x2,
        NVM_ID_CAP_SCRAMBLE     = 0x4,
        NVM_ID_CAP_ENCRYPT      = 0x8,
+
+       /* Memory types */
+       NVM_ID_FMTYPE_SLC       = 0,
+       NVM_ID_FMTYPE_MLC       = 1,
+};
+
+struct nvm_id_lp_mlc {
+       u16     num_pairs;
+       u8      pairs[886];
+};
+
+struct nvm_id_lp_tbl {
+       __u8    id[8];
+       struct nvm_id_lp_mlc mlc;
 };
 
 struct nvm_id_group {
@@ -89,6 +103,8 @@ struct nvm_id_group {
        u32     mpos;
        u32     mccap;
        u16     cpar;
+
+       struct nvm_id_lp_tbl lptbl;
 };
 
 struct nvm_addr_format {
@@ -297,6 +313,10 @@ struct nvm_dev {
        int sec_per_blk;
        int sec_per_lun;
 
+       /* lower page table */
+       int lps_per_blk;
+       int *lptbl;
+
        unsigned long total_pages;
        unsigned long total_blocks;
        int nr_luns;