[PATCH v2 4/5] soc: qcom: smem: Support dynamic item limit

[Chris Lew]

In V12 SMEM, SBL writes SMEM parameter information
after the TOC. Use the SBL provided item count
as the max item number.

Signed-off-by: Chris Lew <clew@xxxxxxxxxxxxxx>
---

Changes since v1:
- Change num_items to __le16 from __le32
- Move max smem item warning to generic get/alloc functions
- Use get ptable helper function

 drivers/soc/qcom/smem.c | 51 +++++++++++++++++++++++++++++++++++++++++++------
 1 file changed, 45 insertions(+), 6 deletions(-)

diff --git a/drivers/soc/qcom/smem.c b/drivers/soc/qcom/smem.c
index 88d5ec663304..2f3b1e1a8904 100644
--- a/drivers/soc/qcom/smem.c
+++ b/drivers/soc/qcom/smem.c
@@ -223,6 +223,24 @@ struct smem_private_entry {
 #define SMEM_PRIVATE_CANARY	0xa5a5
 
 /**
+ * struct smem_info - smem region info located after the table of contents
+ * @magic:	magic number, must be SMEM_INFO_MAGIC
+ * @size:	size of the smem region
+ * @base_addr:	base address of the smem region
+ * @reserved:	for now reserved entry
+ * @num_items:	highest accepted item number
+ */
+struct smem_info {
+	u8 magic[4];
+	__le32 size;
+	__le32 base_addr;
+	__le32 reserved;
+	__le16 num_items;
+};
+
+static const u8 SMEM_INFO_MAGIC[] = { 0x53, 0x49, 0x49, 0x49 }; /* SIII */
+
+/**
  * struct smem_region - representation of a chunk of memory used for smem
  * @aux_base:	identifier of aux_mem base
  * @virt_base:	virtual base address of memory with this aux_mem identifier
@@ -243,6 +261,7 @@ struct smem_region {
  * @partitions:	list of pointers to partitions affecting the current
  *		processor/host
  * @cacheline:	list of cacheline sizes for each host
+ * @item_count: max accepted item number
  * @num_regions: number of @regions
  * @regions:	list of the memory regions defining the shared memory
  */
@@ -255,6 +274,7 @@ struct qcom_smem {
 	size_t global_cacheline;
 	struct smem_partition_header *partitions[SMEM_HOST_COUNT];
 	size_t cacheline[SMEM_HOST_COUNT];
+	u32 item_count;
 
 	unsigned num_regions;
 	struct smem_region regions[0];
@@ -386,9 +406,6 @@ static int qcom_smem_alloc_global(struct qcom_smem *smem,
 	struct smem_global_entry *entry;
 	struct smem_header *header;
 
-	if (WARN_ON(item >= SMEM_ITEM_COUNT))
-		return -EINVAL;
-
 	header = smem->regions[0].virt_base;
 	entry = &header->toc[item];
 	if (entry->allocated)
@@ -439,6 +456,9 @@ int qcom_smem_alloc(unsigned host, unsigned item, size_t size)
 		return -EINVAL;
 	}
 
+	if (WARN_ON(item >= __smem->item_count))
+		return -EINVAL;
+
 	ret = hwspin_lock_timeout_irqsave(__smem->hwlock,
 					  HWSPINLOCK_TIMEOUT,
 					  &flags);
@@ -471,9 +491,6 @@ static void *qcom_smem_get_global(struct qcom_smem *smem,
 	u32 aux_base;
 	unsigned i;
 
-	if (WARN_ON(item >= SMEM_ITEM_COUNT))
-		return ERR_PTR(-EINVAL);
-
 	header = smem->regions[0].virt_base;
 	entry = &header->toc[item];
 	if (!entry->allocated)
@@ -569,6 +586,9 @@ void *qcom_smem_get(unsigned host, unsigned item, size_t *size)
 	if (!__smem)
 		return ptr;
 
+	if (WARN_ON(item >= __smem->item_count))
+		return ERR_PTR(-EINVAL);
+
 	ret = hwspin_lock_timeout_irqsave(__smem->hwlock,
 					  HWSPINLOCK_TIMEOUT,
 					  &flags);
@@ -656,6 +676,22 @@ static struct smem_ptable *qcom_smem_get_ptable(struct qcom_smem *smem)
 	return ptable;
 }
 
+static u32 qcom_smem_get_dynamic_item(struct qcom_smem *smem)
+{
+	struct smem_ptable *ptable;
+	struct smem_info *info;
+
+	ptable = qcom_smem_get_ptable(smem);
+	if (IS_ERR_OR_NULL(ptable))
+		return SMEM_ITEM_COUNT;
+
+	info = (struct smem_info *)&ptable->entry[ptable->num_entries];
+	if (memcmp(info->magic, SMEM_INFO_MAGIC, sizeof(info->magic)))
+		return SMEM_ITEM_COUNT;
+
+	return le16_to_cpu(info->num_items);
+}
+
 static int qcom_smem_set_global_partition(struct qcom_smem *smem)
 {
 	struct smem_partition_header *header;
@@ -883,7 +919,10 @@ static int qcom_smem_probe(struct platform_device *pdev)
 		ret = qcom_smem_set_global_partition(smem);
 		if (ret < 0)
 			return ret;
+		smem->item_count = qcom_smem_get_dynamic_item(smem);
+		break;
 	case SMEM_GLOBAL_HEAP_VERSION:
+		smem->item_count = SMEM_ITEM_COUNT;
 		break;
 	default:
 		dev_err(&pdev->dev, "Unsupported SMEM version 0x%x\n", version);
-- 
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