[net PATCH] wifi: ath11k: fix wrong usage of resource_size() causing firmware panic

[Christian Marangi <ansuelsmth@gmail.com>]

On converting to the of_reserved_mem_region_to_resource() helper with
commit 900730dc4705 ("wifi: ath: Use
of_reserved_mem_region_to_resource() for "memory-region"") a logic error
was introduced in the ath11k_core_coldboot_cal_support() if condition.

The original code checked for hremote_node presence and skipped
ath11k_core_coldboot_cal_support() in the other switch case but now
everything is driven entirely on the values of the resource struct.

resource_size() (in this case) is wrongly assumed to return a size of
zero if the passed resource struct is init to zero. This is not the case
as a resource struct should be always init with correct values (or at
best set the end value to -1 to signal it's not configured)
(the return value of resource_size() for a resource struct with start
and end set to zero is 1)

On top of this, using resource_size() to check if a resource struct is
initialized or not is generally wrong and other measure should be used
instead.

To better handle this, use the DEFINE_RES macro to initialize the
resource struct and set the IORESOURCE_UNSET flag by default.

Replace the resource_size() check with checking for the resource struct
flags and check if it's IORESOURCE_UNSET.

This change effectively restore the original logic and restore correct
loading of the ath11k firmware (restoring correct functionality of
Wi-Fi)

Cc: stable@vger.kernel.org
Fixes: 900730dc4705 ("wifi: ath: Use of_reserved_mem_region_to_resource() for "memory-region"")
Link: https://lore.kernel.org/all/20251207215359.28895-1-ansuelsmth@gmail.com/T/#m990492684913c5a158ff0e5fc90697d8ad95351b
Cc: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Christian Marangi <ansuelsmth@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 ff6a97e328b8..afa663c00620 100644
--- a/drivers/net/wireless/ath/ath11k/qmi.c
+++ b/drivers/net/wireless/ath/ath11k/qmi.c
@@ -2039,8 +2039,8 @@ static int ath11k_qmi_alloc_target_mem_chunk(struct ath11k_base *ab)
 
 static int ath11k_qmi_assign_target_mem_chunk(struct ath11k_base *ab)
 {
+	struct resource res = DEFINE_RES(0, 0, IORESOURCE_UNSET);
 	struct device *dev = ab->dev;
-	struct resource res = {};
 	u32 host_ddr_sz;
 	int i, idx, ret;
 
@@ -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.flags != IORESOURCE_UNSET) {
 					ab->qmi.target_mem[idx].paddr =
 							res.start + host_ddr_sz;
 					ab->qmi.target_mem[idx].iaddr =
-- 
2.51.0