[PATCH ath-next v2 3/3] wifi: ath12k: allocate HOST_DDR and BDF regions after Q6 RO region

Currently, the Q6 region contains a read-only firmware region along with
the BDF_MEM_REGION_TYPE and HOST_DDR_REGION_TYPE memory areas. The firmware
expects these writable memory regions to be assigned after the Q6 read-only
section.

However, the ath12k driver currently allocates the HOST_DDR_REGION_TYPE
starting from the base of the Q6 region, which includes the read-only
firmware area. As a result, the allocated memory regions overlap with the
read-only section, causing the firmware to assert during QMI memory
allocation. The Q6 memory region layout is as follows:

		Q6 Reserved Memory
	+--------------------------------------+
	|                                      |
	|  Read-only Firmware Region           |
	|  (Q6 RO Region)                      |
	|                                      |
	+--------------------------------------+ <--- bdf_addr_offset
	|  Writable Memory Region              |
	|  (BDF + HOST_DDR allocations)        |
	|                                      |
	+--------------------------------------+

Fix this by allocating the required memory regions only after the end of
the read-only region in the Q6 address space. The bdf_addr_offset parameter
indicates where the writable region starts. Both HOST_DDR and BDF regions
are allocated sequentially after this offset, with each region placed
immediately after the previous one to avoid gaps and overlaps.

Tested-on: IPQ5332 hw1.0 AHB WLAN.WBE.1.6-01275-QCAHKSWPL_SILICONZ-1

Fixes: 6757079c5890 ("wifi: ath12k: add support for fixed QMI firmware memory")
Reviewed-by: Rameshkumar Sundaram <[email protected]>
Reviewed-by: Baochen Qiang <[email protected]>
Signed-off-by: Aaradhana Sahu <[email protected]>
---
 drivers/net/wireless/ath/ath12k/qmi.c | 19 +++++++++++++++----
 1 file changed, 15 insertions(+), 4 deletions(-)

diff --git a/drivers/net/wireless/ath/ath12k/qmi.c b/drivers/net/wireless/ath/ath12k/qmi.c
index 5bf045971c94..6d5063229221 100644
--- a/drivers/net/wireless/ath/ath12k/qmi.c
+++ b/drivers/net/wireless/ath/ath12k/qmi.c
@@ -2746,8 +2746,8 @@ static const char *ath12k_qmi_get_mem_reg_name(int mem_type)
 static int ath12k_qmi_assign_target_mem_chunk(struct ath12k_base *ab)
 {
 	struct device_node *np = ab->dev->of_node;
+	size_t avail_rmem_size, offset = 0;
 	struct target_mem_chunk *chunk;
-	size_t avail_rmem_size;
 	struct resource res;
 	const char *rname;
 	int i, idx, ret;
@@ -2781,9 +2781,20 @@ static int ath12k_qmi_assign_target_mem_chunk(struct ath12k_base *ab)
 			goto out;
 
 		avail_rmem_size = resource_size(&res);
-		if (chunk->type == BDF_MEM_REGION_TYPE) {
-			avail_rmem_size -= ab->hw_params->bdf_addr_offset;
-			res.start += ab->hw_params->bdf_addr_offset;
+		if (chunk->type == BDF_MEM_REGION_TYPE ||
+		    chunk->type == HOST_DDR_REGION_TYPE) {
+			if (ab->hw_params->bdf_addr_offset > avail_rmem_size ||
+			    offset > avail_rmem_size - ab->hw_params->bdf_addr_offset) {
+				ath12k_err(ab, "qmi mem offset overflow: bdf_offset=%u offset=%zu size=%zu\n",
+					   ab->hw_params->bdf_addr_offset, offset,
+					   avail_rmem_size);
+				ret = -EINVAL;
+				goto out;
+			}
+
+			avail_rmem_size -= ab->hw_params->bdf_addr_offset + offset;
+			res.start += ab->hw_params->bdf_addr_offset + offset;
+			offset += chunk->size;
 		}
 
 		if (avail_rmem_size < chunk->size) {
-- 
2.34.1