[PATCH] wifi: ath11k: fix qmi memory allocation logic for CALDB region

[Alexandru Gagniuc <mr.nuke.me@gmail.com>]

Memory region assignment in ath11k_qmi_assign_target_mem_chunk()
assumes that:
  1. firmware will make a HOST_DDR_REGION_TYPE request, and
  2. this request is processed before CALDB_MEM_REGION_TYPE

In this case CALDB_MEM_REGION_TYPE, can safely be assigned immediately
after the host region.

However, if the HOST_DDR_REGION_TYPE request is not made, or the
reserved-memory node is not present, then res.start and res.end are 0,
and host_ddr_sz remains uninitialized. The physical address should
fall back to ATH11K_QMI_CALDB_ADDRESS. That doesn't happen:

resource_size(&res) returns 1 for an empty resource, and thus the if
clause never takes the fallback path. ab->qmi.target_mem[idx].paddr
is assigned the uninitialized value of host_ddr_sz + 0 (res.start).

Use "if (res.end > res.start)" for the predicate, which correctly
falls back to ATH11K_QMI_CALDB_ADDRESS.

Fixes: 900730dc4705 ("wifi: ath: Use of_reserved_mem_region_to_resource() for "memory-region"")

Cc: stable@vger.kernel.org # v6.18
Signed-off-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>
---
 drivers/net/wireless/ath/ath11k/qmi.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/wireless/ath/ath11k/qmi.c b/drivers/net/wireless/ath/ath11k/qmi.c
index aea56c38bf8f3..6cc26d1c1e2a4 100644
--- a/drivers/net/wireless/ath/ath11k/qmi.c
+++ b/drivers/net/wireless/ath/ath11k/qmi.c
@@ -2054,7 +2054,7 @@ static int ath11k_qmi_assign_target_mem_chunk(struct ath11k_base *ab)
 				return ret;
 			}
 
-			if (res.end - res.start + 1 < ab->qmi.target_mem[i].size) {
+			if (resource_size(&res) < ab->qmi.target_mem[i].size) {
 				ath11k_dbg(ab, ATH11K_DBG_QMI,
 					   "fail to assign memory of sz\n");
 				return -EINVAL;
@@ -2086,7 +2086,7 @@ static int ath11k_qmi_assign_target_mem_chunk(struct ath11k_base *ab)
 			}
 
 			if (ath11k_core_coldboot_cal_support(ab)) {
-				if (resource_size(&res)) {
+				if (res.end > res.start) {
 					ab->qmi.target_mem[idx].paddr =
 							res.start + host_ddr_sz;
 					ab->qmi.target_mem[idx].iaddr =
-- 
2.45.1