net: ipa: introduce ipa_mem_find()

Introduce a new function that abstracts finding information about a
region in IPA-local memory, given its memory region ID.  For now it
simply uses the region ID as an index into the IPA memory array.
If the region is not defined, ipa_mem_find() returns a null pointer.

Update all code that accesses the ipa->mem[] array directly to use
ipa_mem_find() instead.  The return value must be checked for null
when optional memory regions are sought.

Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 27 insertions, 11 deletions

diff --git a/drivers/net/ipa/ipa_mem.c b/drivers/net/ipa/ipa_mem.c
index 7df5496bdc2e..633895fc67b6 100644
--- a/drivers/net/ipa/ipa_mem.c
+++ b/drivers/net/ipa/ipa_mem.c
@@ -26,12 +26,20 @@
 /* SMEM host id representing the modem. */
 #define QCOM_SMEM_HOST_MODEM	1
 
+const struct ipa_mem *ipa_mem_find(struct ipa *ipa, enum ipa_mem_id mem_id)
+{
+	if (mem_id < IPA_MEM_COUNT)
+		return &ipa->mem[mem_id];
+
+	return NULL;
+}
+
 /* Add an immediate command to a transaction that zeroes a memory region */
 static void
 ipa_mem_zero_region_add(struct gsi_trans *trans, enum ipa_mem_id mem_id)
 {
 	struct ipa *ipa = container_of(trans->gsi, struct ipa, gsi);
-	const struct ipa_mem *mem = &ipa->mem[mem_id];
+	const struct ipa_mem *mem = ipa_mem_find(ipa, mem_id);
 	dma_addr_t addr = ipa->zero_addr;
 
 	if (!mem->size)
@@ -61,6 +69,7 @@ ipa_mem_zero_region_add(struct gsi_trans *trans, enum ipa_mem_id mem_id)
 int ipa_mem_setup(struct ipa *ipa)
 {
 	dma_addr_t addr = ipa->zero_addr;
+	const struct ipa_mem *mem;
 	struct gsi_trans *trans;
 	u32 offset;
 	u16 size;
@@ -75,12 +84,16 @@ int ipa_mem_setup(struct ipa *ipa)
 		return -EBUSY;
 	}
 
-	/* Initialize IPA-local header memory.  The modem and AP header
-	 * regions are contiguous, and initialized together.
+	/* Initialize IPA-local header memory.  The AP header region, if
+	 * present, is contiguous with and follows the modem header region,
+	 * and they are initialized together.
 	 */
-	offset = ipa->mem[IPA_MEM_MODEM_HEADER].offset;
-	size = ipa->mem[IPA_MEM_MODEM_HEADER].size;
-	size += ipa->mem[IPA_MEM_AP_HEADER].size;
+	mem = ipa_mem_find(ipa, IPA_MEM_MODEM_HEADER);
+	offset = mem->offset;
+	size = mem->size;
+	mem = ipa_mem_find(ipa, IPA_MEM_AP_HEADER);
+	if (mem)
+		size += mem->size;
 
 	ipa_cmd_hdr_init_local_add(trans, offset, size, addr);
 
@@ -91,7 +104,8 @@ int ipa_mem_setup(struct ipa *ipa)
 	gsi_trans_commit_wait(trans);
 
 	/* Tell the hardware where the processing context area is located */
-	offset = ipa->mem_offset + ipa->mem[IPA_MEM_MODEM_PROC_CTX].offset;
+	mem = ipa_mem_find(ipa, IPA_MEM_MODEM_PROC_CTX);
+	offset = ipa->mem_offset + mem->offset;
 	val = proc_cntxt_base_addr_encoded(ipa->version, offset);
 	iowrite32(val, ipa->reg_virt + IPA_REG_LOCAL_PKT_PROC_CNTXT_OFFSET);
 
@@ -294,6 +308,7 @@ static bool ipa_mem_size_valid(struct ipa *ipa)
 int ipa_mem_config(struct ipa *ipa)
 {
 	struct device *dev = &ipa->pdev->dev;
+	const struct ipa_mem *mem;
 	dma_addr_t addr;
 	u32 mem_size;
 	void *virt;
@@ -334,11 +349,11 @@ int ipa_mem_config(struct ipa *ipa)
 	 * space prior to the region's base address if indicated.
 	 */
 	for (i = 0; i < ipa->mem_count; i++) {
-		const struct ipa_mem *mem = &ipa->mem[i];
 		u16 canary_count;
 		__le32 *canary;
 
 		/* Skip over undefined regions */
+		mem = &ipa->mem[i];
 		if (!mem->offset && !mem->size)
 			continue;
 
@@ -361,8 +376,9 @@ int ipa_mem_config(struct ipa *ipa)
 	if (!ipa_cmd_data_valid(ipa))
 		goto err_dma_free;
 
-	/* Verify the microcontroller ring alignment (0 is OK too) */
-	if (ipa->mem[IPA_MEM_UC_EVENT_RING].offset % 1024) {
+	/* Verify the microcontroller ring alignment (if defined) */
+	mem = ipa_mem_find(ipa, IPA_MEM_UC_EVENT_RING);
+	if (mem && mem->offset % 1024) {
 		dev_err(dev, "microcontroller ring not 1024-byte aligned\n");
 		goto err_dma_free;
 	}
@@ -527,7 +543,7 @@ static int ipa_smem_init(struct ipa *ipa, u32 item, size_t size)
 	 * (in this case, the modem).  An allocation from SMEM is persistent
 	 * until the AP reboots; there is no way to free an allocated SMEM
 	 * region.  Allocation only reserves the space; to use it you need
-	 * to "get" a pointer it (this implies no reference counting).
+	 * to "get" a pointer it (this does not imply reference counting).
 	 * The item might have already been allocated, in which case we
 	 * use it unless the size isn't what we expect.
 	 */