powerpc/nvdimm: Add support for multibyte read/write for metadata

SCM_READ/WRITE_MEATADATA hcall supports multibyte read/write. This patch
updates the metadata read/write to use 1, 2, 4 or 8 byte read/write as
mentioned in PAPR document.

READ/WRITE_METADATA hcall supports the 1, 2, 4, or 8 bytes read/write.
For other values hcall results H_P3.

Hypervisor stores the metadata contents in big-endian format and in-order
to enable read/write in different granularity, we need to switch the contents
to big-endian before calling HCALL.

Based on an patch from Oliver O'Halloran <oohall@gmail.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

diff --git a/arch/powerpc/platforms/pseries/papr_scm.c b/arch/powerpc/platforms/pseries/papr_scm.c
index 0176ce6..80fbab1 100644 (file)
--- a/arch/powerpc/platforms/pseries/papr_scm.c
+++ b/arch/powerpc/platforms/pseries/papr_scm.c
@@ -97,42 +97,102 @@ static int drc_pmem_unbind(struct papr_scm_priv *p)
 }
 
 static int papr_scm_meta_get(struct papr_scm_priv *p,
-                       struct nd_cmd_get_config_data_hdr *hdr)
+                            struct nd_cmd_get_config_data_hdr *hdr)
 {
        unsigned long data[PLPAR_HCALL_BUFSIZE];
+       unsigned long offset, data_offset;
+       int len, read;
        int64_t ret;
 
-       if (hdr->in_offset >= p->metadata_size || hdr->in_length != 1)
+       if ((hdr->in_offset + hdr->in_length) >= p->metadata_size)
                return -EINVAL;
 
-       ret = plpar_hcall(H_SCM_READ_METADATA, data, p->drc_index,
-                       hdr->in_offset, 1);
-
-       if (ret == H_PARAMETER) /* bad DRC index */
-               return -ENODEV;
-       if (ret)
-               return -EINVAL; /* other invalid parameter */
-
-       hdr->out_buf[0] = data[0] & 0xff;
-
+       for (len = hdr->in_length; len; len -= read) {
+
+               data_offset = hdr->in_length - len;
+               offset = hdr->in_offset + data_offset;
+
+               if (len >= 8)
+                       read = 8;
+               else if (len >= 4)
+                       read = 4;
+               else if (len >= 2)
+                       read = 2;
+               else
+                       read = 1;
+
+               ret = plpar_hcall(H_SCM_READ_METADATA, data, p->drc_index,
+                                 offset, read);
+
+               if (ret == H_PARAMETER) /* bad DRC index */
+                       return -ENODEV;
+               if (ret)
+                       return -EINVAL; /* other invalid parameter */
+
+               switch (read) {
+               case 8:
+                       *(uint64_t *)(hdr->out_buf + data_offset) = be64_to_cpu(data[0]);
+                       break;
+               case 4:
+                       *(uint32_t *)(hdr->out_buf + data_offset) = be32_to_cpu(data[0] & 0xffffffff);
+                       break;
+
+               case 2:
+                       *(uint16_t *)(hdr->out_buf + data_offset) = be16_to_cpu(data[0] & 0xffff);
+                       break;
+
+               case 1:
+                       *(uint8_t *)(hdr->out_buf + data_offset) = (data[0] & 0xff);
+                       break;
+               }
+       }
        return 0;
 }
 
 static int papr_scm_meta_set(struct papr_scm_priv *p,
-                       struct nd_cmd_set_config_hdr *hdr)
+                            struct nd_cmd_set_config_hdr *hdr)
 {
+       unsigned long offset, data_offset;
+       int len, wrote;
+       unsigned long data;
+       __be64 data_be;
        int64_t ret;
 
-       if (hdr->in_offset >= p->metadata_size || hdr->in_length != 1)
+       if ((hdr->in_offset + hdr->in_length) >= p->metadata_size)
                return -EINVAL;
 
-       ret = plpar_hcall_norets(H_SCM_WRITE_METADATA,
-                       p->drc_index, hdr->in_offset, hdr->in_buf[0], 1);
-
-       if (ret == H_PARAMETER) /* bad DRC index */
-               return -ENODEV;
-       if (ret)
-               return -EINVAL; /* other invalid parameter */
+       for (len = hdr->in_length; len; len -= wrote) {
+
+               data_offset = hdr->in_length - len;
+               offset = hdr->in_offset + data_offset;
+
+               if (len >= 8) {
+                       data = *(uint64_t *)(hdr->in_buf + data_offset);
+                       data_be = cpu_to_be64(data);
+                       wrote = 8;
+               } else if (len >= 4) {
+                       data = *(uint32_t *)(hdr->in_buf + data_offset);
+                       data &= 0xffffffff;
+                       data_be = cpu_to_be32(data);
+                       wrote = 4;
+               } else if (len >= 2) {
+                       data = *(uint16_t *)(hdr->in_buf + data_offset);
+                       data &= 0xffff;
+                       data_be = cpu_to_be16(data);
+                       wrote = 2;
+               } else {
+                       data_be = *(uint8_t *)(hdr->in_buf + data_offset);
+                       data_be &= 0xff;
+                       wrote = 1;
+               }
+
+               ret = plpar_hcall_norets(H_SCM_WRITE_METADATA, p->drc_index,
+                                        offset, data_be, wrote);
+               if (ret == H_PARAMETER) /* bad DRC index */
+                       return -ENODEV;
+               if (ret)
+                       return -EINVAL; /* other invalid parameter */
+       }
 
        return 0;
 }
@@ -154,7 +214,7 @@ int papr_scm_ndctl(struct nvdimm_bus_descriptor *nd_desc, struct nvdimm *nvdimm,
                get_size_hdr = buf;
 
                get_size_hdr->status = 0;
-               get_size_hdr->max_xfer = 1;
+               get_size_hdr->max_xfer = 8;
                get_size_hdr->config_size = p->metadata_size;
                *cmd_rc = 0;
                break;