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>

diff --git a/drivers/soc/qcom/smem.c b/drivers/soc/qcom/smem.c
index 91f8149..eb530a6 100644 (file)
--- 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);