Subject: [PATCH v2 1/8] soc: qcom: Make qcom_smem_get() return a pointer

From: [email-masked] (Stephen Boyd)
Date: Wed, 2 Sep 2015 15:46:44 -0700

Passing a void ** almost always requires a cast at the call site.
Instead of littering the code with casts every time this function
is called, have qcom_smem_get() return a void pointer to the
location of the smem item. This frees the caller from having to
cast the pointer.

Cc: Bjorn Andersson <[email-masked]>
Signed-off-by: Stephen Boyd <[email-masked]>
---

Changes since v1:
 * Moved to before the smem big endian patch

 drivers/soc/qcom/smd.c        | 30 +++++++++---------
 drivers/soc/qcom/smem.c       | 72 +++++++++++++++++++------------------------
 include/linux/soc/qcom/smem.h |  2 +-
 3 files changed, 48 insertions(+), 56 deletions(-)

diff --git a/drivers/soc/qcom/smd.c b/drivers/soc/qcom/smd.c
index edd9d9a37238..aa65c07f281e 100644
--- a/drivers/soc/qcom/smd.c
+++ b/drivers/soc/qcom/smd.c
@@ -978,10 +978,11 @@ static struct qcom_smd_channel *qcom_smd_create_channel(struct qcom_smd_edge *ed
 	spin_lock_init(&channel->recv_lock);
 	init_waitqueue_head(&channel->fblockread_event);
 
-	ret = qcom_smem_get(edge->remote_pid, smem_info_item, (void **)&info,
-			    &info_size);
-	if (ret)
+	info = qcom_smem_get(edge->remote_pid, smem_info_item, &info_size);
+	if (IS_ERR(info)) {
+		ret = PTR_ERR(info);
 		goto free_name_and_channel;
+	}
 
 	/*
 	 * Use the size of the item to figure out which channel info struct to
@@ -1000,10 +1001,11 @@ static struct qcom_smd_channel *qcom_smd_create_channel(struct qcom_smd_edge *ed
 		goto free_name_and_channel;
 	}
 
-	ret = qcom_smem_get(edge->remote_pid, smem_fifo_item, &fifo_base,
-			    &fifo_size);
-	if (ret)
+	fifo_base = qcom_smem_get(edge->remote_pid, smem_fifo_item, &fifo_size);
+	if (IS_ERR(fifo_base)) {
+		ret =  PTR_ERR(fifo_base);
 		goto free_name_and_channel;
+	}
 
 	/* The channel consist of a rx and tx fifo of equal size */
 	fifo_size /= 2;
@@ -1040,16 +1042,13 @@ static void qcom_discover_channels(struct qcom_smd_edge *edge)
 	unsigned long flags;
 	unsigned fifo_id;
 	unsigned info_id;
-	int ret;
 	int tbl;
 	int i;
 
 	for (tbl = 0; tbl < SMD_ALLOC_TBL_COUNT; tbl++) {
-		ret = qcom_smem_get(edge->remote_pid,
-				    smem_items[tbl].alloc_tbl_id,
-				    (void **)&alloc_tbl,
-				    NULL);
-		if (ret < 0)
+		alloc_tbl = qcom_smem_get(edge->remote_pid,
+				    smem_items[tbl].alloc_tbl_id, NULL);
+		if (IS_ERR(alloc_tbl))
 			continue;
 
 		for (i = 0; i < SMD_ALLOC_TBL_SIZE; i++) {
@@ -1227,11 +1226,12 @@ static int qcom_smd_probe(struct platform_device *pdev)
 	int num_edges;
 	int ret;
 	int i = 0;
+	void *p;
 
 	/* Wait for smem */
-	ret = qcom_smem_get(QCOM_SMEM_HOST_ANY, smem_items[0].alloc_tbl_id, NULL, NULL);
-	if (ret == -EPROBE_DEFER)
-		return ret;
+	p = qcom_smem_get(QCOM_SMEM_HOST_ANY, smem_items[0].alloc_tbl_id, NULL);
+	if (PTR_ERR(p) == -EPROBE_DEFER)
+		return PTR_ERR(p);
 
 	num_edges = of_get_available_child_count(pdev->dev.of_node);
 	array_size = sizeof(*smd) + num_edges * sizeof(struct qcom_smd_edge);
diff --git a/drivers/soc/qcom/smem.c b/drivers/soc/qcom/smem.c
index f402a606eb7d..e6d0dae63845 100644
--- a/drivers/soc/qcom/smem.c
+++ b/drivers/soc/qcom/smem.c
@@ -378,10 +378,9 @@ int qcom_smem_alloc(unsigned host, unsigned item, size_t size)
 }
 EXPORT_SYMBOL(qcom_smem_alloc);
 
-static int qcom_smem_get_global(struct qcom_smem *smem,
-				unsigned item,
-				void **ptr,
-				size_t *size)
+static void *qcom_smem_get_global(struct qcom_smem *smem,
+				  unsigned item,
+				  size_t *size)
 {
 	struct smem_header *header;
 	struct smem_region *area;
@@ -390,36 +389,32 @@ static int qcom_smem_get_global(struct qcom_smem *smem,
 	unsigned i;
 
 	if (WARN_ON(item >= SMEM_ITEM_COUNT))
-		return -EINVAL;
+		return ERR_PTR(-EINVAL);
 
 	header = smem->regions[0].virt_base;
 	entry = &header->toc[item];
 	if (!entry->allocated)
-		return -ENXIO;
+		return ERR_PTR(-ENXIO);
 
-	if (ptr != NULL) {
-		aux_base = entry->aux_base & AUX_BASE_MASK;
+	aux_base = entry->aux_base & AUX_BASE_MASK;
 
-		for (i = 0; i < smem->num_regions; i++) {
-			area = &smem->regions[i];
+	for (i = 0; i < smem->num_regions; i++) {
+		area = &smem->regions[i];
 
-			if (area->aux_base == aux_base || !aux_base) {
-				*ptr = area->virt_base + entry->offset;
-				break;
-			}
+		if (area->aux_base == aux_base || !aux_base) {
+			if (size != NULL)
+				*size = entry->size;
+			return area->virt_base + entry->offset;
 		}
 	}
-	if (size != NULL)
-		*size = entry->size;
 
-	return 0;
+	return ERR_PTR(-ENOENT);
 }
 
-static int qcom_smem_get_private(struct qcom_smem *smem,
-				 unsigned host,
-				 unsigned item,
-				 void **ptr,
-				 size_t *size)
+static void *qcom_smem_get_private(struct qcom_smem *smem,
+				   unsigned host,
+				   unsigned item,
+				   size_t *size)
 {
 	struct smem_partition_header *phdr;
 	struct smem_private_entry *hdr;
@@ -435,55 +430,54 @@ static int qcom_smem_get_private(struct qcom_smem *smem,
 			dev_err(smem->dev,
 				"Found invalid canary in host %d partition\n",
 				host);
-			return -EINVAL;
+			return ERR_PTR(-EINVAL);
 		}
 
 		if (hdr->item == item) {
-			if (ptr != NULL)
-				*ptr = p + sizeof(*hdr) + hdr->padding_hdr;
-
 			if (size != NULL)
 				*size = hdr->size - hdr->padding_data;
 
-			return 0;
+			return p + sizeof(*hdr) + hdr->padding_hdr;
 		}
 
 		p += sizeof(*hdr) + hdr->padding_hdr + hdr->size;
 	}
 
-	return -ENOENT;
+	return ERR_PTR(-ENOENT);
 }
 
 /**
  * qcom_smem_get() - resolve ptr of size of a smem item
  * @host:	the remote processor, or -1
  * @item:	smem item handle
- * @ptr:	pointer to be filled out with address of the item
  * @size:	pointer to be filled out with size of the item
  *
- * Looks up pointer and size of a smem item.
+ * Looks up smem item and returns pointer to it. Size of smem
+ * item is returned in @size.
  */
-int qcom_smem_get(unsigned host, unsigned item, void **ptr, size_t *size)
+void *qcom_smem_get(unsigned host, unsigned item, size_t *size)
 {
 	unsigned long flags;
 	int ret;
+	void *ptr = ERR_PTR(-EPROBE_DEFER);
 
 	if (!__smem)
-		return -EPROBE_DEFER;
+		return ptr;
 
 	ret = hwspin_lock_timeout_irqsave(__smem->hwlock,
 					  HWSPINLOCK_TIMEOUT,
 					  &flags);
 	if (ret)
-		return ret;
+		return ERR_PTR(ret);
 
 	if (host < SMEM_HOST_COUNT && __smem->partitions[host])
-		ret = qcom_smem_get_private(__smem, host, item, ptr, size);
+		ptr = qcom_smem_get_private(__smem, host, item, size);
 	else
-		ret = qcom_smem_get_global(__smem, item, ptr, size);
+		ptr = qcom_smem_get_global(__smem, item, size);
 
 	hwspin_unlock_irqrestore(__smem->hwlock, &flags);
-	return ret;
+
+	return ptr;
 
 }
 EXPORT_SYMBOL(qcom_smem_get);
@@ -520,11 +514,9 @@ static int qcom_smem_get_sbl_version(struct qcom_smem *smem)
 {
 	unsigned *versions;
 	size_t size;
-	int ret;
 
-	ret = qcom_smem_get_global(smem, SMEM_ITEM_VERSION,
-				   (void **)&versions, &size);
-	if (ret < 0) {
+	versions = qcom_smem_get_global(smem, SMEM_ITEM_VERSION, &size);
+	if (IS_ERR(versions)) {
 		dev_err(smem->dev, "Unable to read the version item\n");
 		return -ENOENT;
 	}
diff --git a/include/linux/soc/qcom/smem.h b/include/linux/soc/qcom/smem.h
index bc9630d3aced..785e196ee2ca 100644
--- a/include/linux/soc/qcom/smem.h
+++ b/include/linux/soc/qcom/smem.h
@@ -4,7 +4,7 @@
 #define QCOM_SMEM_HOST_ANY -1
 
 int qcom_smem_alloc(unsigned host, unsigned item, size_t size);
-int qcom_smem_get(unsigned host, unsigned item, void **ptr, size_t *size);
+void *qcom_smem_get(unsigned host, unsigned item, size_t *size);
 
 int qcom_smem_get_free_space(unsigned host);
 
-- 
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