soc: qcom: smem: introduce qcom_smem_partition_header()

Create a new function qcom_smem_partition_header() to encapsulate
validating locating a partition header and validating information
found within it.  This will be built up over a few commits to make
it more obvious how the common function is replacing duplicated code
elsewhere.  Initially it just verifies the header has the right
magic number.

Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: Andy Gross <andy.gross@linaro.org>

1 files changed, 31 insertions, 14 deletions

diff --git a/drivers/soc/qcom/smem.c b/drivers/soc/qcom/smem.c
index 91f814900ca1..eb530a6770c1 100644
--- a/drivers/soc/qcom/smem.c
+++ b/drivers/soc/qcom/smem.c
@@ -723,6 +723,29 @@ static u32 qcom_smem_get_item_count(struct qcom_smem *smem)
         return le16_to_cpu(info->num_items);
 }
 
+/*
+ * Validate the partition header for a partition whose partition
+ * table entry is supplied.  Returns a pointer to its header if
+ * valid, or a null pointer otherwise.
+ */
+static struct smem_partition_header *
+qcom_smem_partition_header(struct qcom_smem *smem,
+                struct smem_ptable_entry *entry)
+{
+        struct smem_partition_header *header;
+
+        header = smem->regions[0].virt_base + le32_to_cpu(entry->offset);
+
+        if (memcmp(header->magic, SMEM_PART_MAGIC, sizeof(header->magic))) {
+                dev_err(smem->dev, "bad partition magic %02x %02x %02x %02x\n",
+                        header->magic[0], header->magic[1],
+                        header->magic[2], header->magic[3]);
+                return NULL;
+        }
+
+        return header;
+}
+
 static int qcom_smem_set_global_partition(struct qcom_smem *smem)
 {
         struct smem_partition_header *header;
@@ -761,15 +784,13 @@ static int qcom_smem_set_global_partition(struct qcom_smem *smem)
                 return -EINVAL;
         }
 
-        header = smem->regions[0].virt_base + le32_to_cpu(entry->offset);
+        header = qcom_smem_partition_header(smem, entry);
+        if (!header)
+                return -EINVAL;
+
         host0 = le16_to_cpu(header->host0);
         host1 = le16_to_cpu(header->host1);
 
-        if (memcmp(header->magic, SMEM_PART_MAGIC, sizeof(header->magic))) {
-                dev_err(smem->dev, "Global partition has invalid magic\n");
-                return -EINVAL;
-        }
-
         if (host0 != SMEM_GLOBAL_HOST || host1 != SMEM_GLOBAL_HOST) {
                 dev_err(smem->dev, "Global partition hosts are invalid\n");
                 return -EINVAL;
@@ -837,17 +858,13 @@ static int qcom_smem_enumerate_partitions(struct qcom_smem *smem,
                         return -EINVAL;
                 }
 
-                header = smem->regions[0].virt_base + le32_to_cpu(entry->offset);
+                header = qcom_smem_partition_header(smem, entry);
+                if (!header)
+                        return -EINVAL;
+
                 host0 = le16_to_cpu(header->host0);
                 host1 = le16_to_cpu(header->host1);
 
-                if (memcmp(header->magic, SMEM_PART_MAGIC,
-                            sizeof(header->magic))) {
-                        dev_err(smem->dev,
-                                "Partition %d has invalid magic\n", i);
-                        return -EINVAL;
-                }
-
                 if (host0 != host0 || host1 != host1) {
                         dev_err(smem->dev,
                                 "Partition %d hosts don't match\n", i);